GPS World

Category: Opinions

  • Survey Perspectives: About Alaska

    I wish I could share with you what I’m seeing right now. I’m on a scenic train in Alaska, traveling from Anchorage to Fairbanks. From someone who usually travels by air, scurrying through airport security at the last minute, this is the way to travel…truly relaxing. There’s lots of space to walk around and a dining car to boot. The views are fantastic. The special cars of the Alaska Railroad are built with large picture windows for soaking in the scenery. On a good day, you can see Mount McKinley (Denali, at right) along the route. We won’t see it today. It’s cloudy and snowing. But we have seen moose (and even had to stop for one that didn’t want to get off the tracks). The train will stop for residents who flag it down and need a ride to the next town. The conductor will even stop the train for picture-taking if the view warrants, which it did when we saw a wolf trying to chase down three sheep on a rock slope along a river.

    One thing we shouldn’t expect is to be in a hurry. We left at 8:30 a.m. and we’ll arrive 11.5 hours later. We’ll probably arrive later than that, according to the conductor, “due to circumstances along the way.” He says, “If you’re in a hurry, you’re traveling the wrong way.”

    There will be many stops along the way. At the moment, we are stopped for a few minutes in Wasilla…of Sarah Palin fame. It’s a small town. The train has stopped in the middle of Wasilla, holding up all traffic, while 26 Boy scouts come on board only to get dumped off 45 minutes later in the middle of nowhere to camp for the weekend in the harsh Alaskan weather. Today, the temperature is rather balmy at 20° F. A month ago, it was -40° F in Fairbanks for a couple of weeks. As one resident exclaimed, “Once it’s below 0° F, it’s all about the same…really cold.”

    Rudy Musial lives along the tracks about 30 minutes or so north of Wasilla. To you baseball fans, his family name may sound familiar. According to Conductor Steve, Rudy is a cousin of Stan Musial, the famous professional baseball player of the earlier part of last century. From what Conductor Steve says, who’s spent some time fishing with Rudy, Rudy was a formidable baseball player himself. Now retired at 78, Rudy was a surveyor for the Bureau of Land Management.

    When the train passed by Rudy’s house a few minutes ago, at 60 mph, Steve tossed a newspaper to Rudy. It’s something he does for Rudy and many others who live along the tracks. They don’t subscribe to the newspaper, and Conductor Steve isn’t obligated; he does it out of kindness and in the name of fellowship. It’s a central theme I’ve noticed on this trip to Alaska and the several times I’ve been here before. Alaskans are generally very kind, warm people.

    I tell people Oregon is for people who love Mother Nature and the outdoors. Alaska is Oregon on a grand scale, and you develop a new respect Mother Nature. She is beautiful, yet deadly. One wrong turn here and you might not make it back home.

    The reason I came to Alaska was for the annual Alaska Surveying and Mapping Conference. I normally don’t take the time to attend state conferences because there are so many, but Alaska is unique. From a mapping standpoint, the state’s been somewhat “left in the cold.” There’s not much state-level data available like there is in the lower 48 states. The density of GPS CORS is sparse and only improved recently with the inclusion of the four new WAAS Reference Stations (WRS) in Barrow, Bethel, Kotzebue, and Fairbanks.

    There is good orthophotography in the metro areas, but metro areas are few (Anchorage, Fairbanks, and southeast Alaska). Much of Alaska is a vast amount of wilderness. Height modernization is only a distant dream. I heard that only 1% to 2% of the USGS quad sheets have been field checked, and some elevation busts are on the order of hundreds of feet. That’s sort of scary when you consider that the Alaskan terrain database for aviation is based on the USGS elevation data. You may not know it, but flying in Alaska is some of the most treacherous flying in North America. The weather is largely harsh and unpredictable and there are a lot of small commercial and private planes buzzing around because the road infrastructure is scarce.

    GPS, along with WAAS corrections, have become a must-have tool for Alaskan aviators. GPS accuracy and coverage far exceeds any previous aviation navigation technology. It’s so accurate, in fact, that it’s flushing out the USGS quad sheet errors. Actually, that’s been happening for years. I recall, “GPS putting me on the wrong side of the river” in the ‘90s. But as our lives become more dependent on digital map data, the consequences have become more severe. In Alaska, it’s a life-or-death proposition because aviation terrain databases used by pilots are based on those legacy USGS quad sheets. Flying low in inclement weather using accurate GPS positioning + inaccurate digital terrain maps = an intersection with the ground at some point.

    Accurate positioning within less accurate maps is a theme that’s central to the surveying/mapping community. GPS accuracy has improved and will continue to improve. In the next decade, a nominal constellation of GPS satellites will exist that are broadcasting the new L5 signal. Everyone will enjoy accuracy at the decimeter level, not just those with expensive “survey-grade” equipment. Pinpoint GPS accuracy will expose glaring errors in our existing map databases. Reconciling those maps is a scary proposition and to most I’ve spoken to, a task that is unfathomable at this point.

    Geodesists and geodesy tools that can help tackle this problem, I suspect, will be in great demand.

    Also in the March newsletter:Follow up on the GPS/GNSS Buyer’s Guide Webinar

  • Voxels: Not Your Daddy’s GIS

    Can statistics and GIS build a more accurate geospatial picture?

    By Art Kalinski, GISP

    I’m a little late with this month’s column, but it was for a good reason: I had the responsibility (and honor) of swearing in my daughter at her Navy Officer Candidate School graduation in Newport, Rhode Island. It was a bizarre feeling seeing her stand on the same drill deck where I stood 37 years ago.

    Seeing all those fine young men and women at the ceremony reminded me what a privilege it was to serve. I may not have thought so at the time, but now, years later, I know it was. Since you won’t hear it enough, to all of you who are or were on active duty: Thank you for serving your country.

    Of course, there are other ways to serve as well, such as creating technologies that can support our first responders and military personnel. A few months ago, I learned about one that was new to me: voxels. With computers growing in power and speed, and richer, more complex datasets being developed, it will surely become more commonplace.

    The term “voxel” grew from the words “volumetric” and “pixel”; it describes resolution in volumetric 3D space, not camera or flat-screen resolution. Think of it as the difference between a checkerboard and the construction toy Legos. Voxels are spatial data structures that not only describe 3D space, but can also display statistically fuzzy data.

    3D Models: Simulation vs. Reality

    For those of you not familiar with voxels, let’s start with GRID or Spatial Analyst, which is a grid cell-based GIS. (If you need a refresher, see my column in the June 2008 edition of GeoIntelligence Insider.) Spatial Analyst is similar to a checkerboard: a 2D space consisting of square cells with values defined in the cells by the checkers. You can even show 3D-like effects by raising or extruding each cell based on elevation data, and then draping an ortho image over the resultant surface.

    People call this 3D, but it really isn’t; no matter which way you look at the model, the draped image is still a 2D photo. The other limitation is that, for the most part, all the elevation starts from a theoretical ground plane. There is no easy way to show holes in the space such as overhanging cliffs, caves, bridge underpasses, etc. (Yes, I know there are ways to get around this limitation, but not elegantly.)

    There have been efforts to create 3D models of buildings using ortho imagery by extruding the buildings from their footprints, but since the side views of the buildings are limited, the quality is poor and limited to one side, if any. This is where geo-referenced oblique imagery has benefited 3D model creation. Since the geo-referenced oblique images show each side of a building in very high resolution and contain the data needed to automatically generate the 3D wireframes, the resultant models are very easy to create and are not only photo-realistic, but photo-accurate.

    Although the application is still in its infancy, 3D models are also where voxels show the greatest potential. Since each volumetric cell is a 3D object in 3D space, complex 3D objects are easy to define. Just like the Legos example, you can build almost any 3D object with voxels. But Legos are solid little cubes, whose presence and location are not ambiguous; they can be there, or not there, period. They are never “maybe there” or fuzzy in their location.

    Voxels have another key benefit: they can be statistically defined. By that I mean that each voxel can display the probability that it exists. If you have data that clearly defines a particular area, that region will have a very solid and unambiguous appearance. But if the data is missing, weak, or sparse, the area will appear porous instead. This is where the human observer’s mind can — and does — fill in the voids. The observer automatically understands that there is incomplete data in those places.

    Building Body Models

    Voxels have been around for a while in the video gaming industry, for the very reason that caves and overhangs can be displayed. Their most serious use, however, has been in building the images created from MRI (magnetic resonance imaging). There they have been a boon to physicians, who can manipulate the 3D images, viewing them from any direction. Additionally, each voxel can have varying degrees of transparency, aiding the physician in comprehending the objects he or she is reviewing.

    This is an ideal environment for voxels, since the MRI scan creates very complete datasets to populate the voxel space. Each MRI scan, like the one shown at left, is a 2D “slice” of the 3D object. Assembling all the slices creates an almost perfect 3D model.

    Image courtesy of Lockheed Martin.
    Image courtesy of Lockheed Martin.

    Voxels and Imagery

    There are many more ways of building 3D models that are not as easy as assembling finite, regular slices of a 3D object, and this is where things get complicated and messy. Kirk Smedley and Mark Pritt of Lockheed Martin are leading a team of researchers exploring ways to apply voxel technology to transform the traditional “TCPED” imagery chain. (For more information on this subject, you can contact Smedley at [email protected].) TCPED (short for tasking, collection, processing, exploitation, and dissemination) is shorthand for the well-established life cycle of imagery, from capture all the way to desktop application.

    Lockheed’s work is based on the groundbreaking research of Dr. Joseph Mundy at Brown University, who continues to work very closely with Lockheed. The Lockheed/Brown team is performing some very sophisticated investigations into 3D voxel model creation using multiple imagery and data sources. None are as clean as the regular slices of an MRI, but instead are statistical products that generate probability distributions. Think principal component analysis, factor analysis, and Eigen value decomposition.

    Yes, it hurts my brain to even think about those long-forgotten statistical methods, but for the brave few who are comfortable in those environments, the voxel is ideal — it can display very complex and imperfect data sets. Not only complex in size, shape, and location, but complex as temporal values and abstract probability distributions.

    This ability to display incomplete or imperfect data accurately in a 3D model is important to Lockheed’s clients. There are many video games or training simulators that provide photo-realistic environments; much of the imagery they use is simulated by cloning or modifying textures or images from real life. However, this technique is unacceptable for use by mission planners or first responders in combat or tactical situations. With lives at stake, they need to know exactly what they will face. The 3D model has to show true reality, and display unknown areas as “unknown” or “no data.” For example, in the 3D models that are created by Pictometry and PLW, if there is no satisfactory imagery available for part of a building, that part is shown as a plain, black surface. One can’t add in a fake window or door that has no counterpart in the real world. It’s much better to show the unknown as such.

    Voxels are especially well suited to show fuzziness or incomplete data not just as black, no-data representations, but as probability displays that can show fuzzy data as incomplete or semi-transparent voxels.

    The varying transparency of voxels can indicate the relative completeness of data.
    The varying transparency of voxels can indicate the relative completeness of data. Image courtesy of Lockheed Martin.

    Voxels are also ideally suited to create temporal models (which some prefer to call 4D models). Here again, the ability of voxels to display data as probability distributions is even more important for temporal data, which may be fuzzy in some locations and vary in fuzziness over time. Researchers are now looking at the possibility of populating voxel space with multiple images (ground stills, oblique aerial images, video, LIDAR, interior stills, CAD, GIS) in a kind of 3D statistical summary version of Microsoft PhotoSynth.

    We may eventually see a seamless environment, inside and out, with accurately represented data that was statistically assembled. This is not your father’s “points, lines, and polygons” GIS. Are you imagining the potential for the GIS community? I see this as yet another example of the CAD, GIS, imagery, and BIM worlds coming together for the benefit of first responders and the military.

  • Survey Perspectives: What’s Your Occupation Time?

    A reader wrote me about occupation times for RTK work, and it’s spurred a conversation I think will be interesting to you and perhaps a little controversial. It seems that most GPS/GNSS users have developed their own opinion based on their own experience.

    The discussion has several points, but the one I’d like to address in this column is the occupation time for RTK points. I’m not referring to the topo type of point where you’re collecting somewhere between 1 to 5 seconds (and averaging) of data, but rather the RTK shot where you want the highest confidence and accuracy in the RTK position.

    I realize that most, if not all, manufacturers advise (or design into their software) that 180 seconds of data is sufficient for an RTK shot where the purpose of that point is to establish secondary control.

    The reader offered that he “couldn’t imagine that we are getting a good solution with anything less than 120 epochs.”

    I scratched my head on this one, and even checked with a few GNSS engineer friends of mine about the upside of occupying a point with RTK for 180 seconds (assuming a 1 Hz rate) rather than 30 seconds, or even 15 seconds for that matter.

    First of all, there are several assumptions in this conversation:

    • You have clear view of the sky.
    • It is clear of multipath-enabling obstructions.
    • Six or more GPS satellites are being tracked with a low PDOP.

    The first thought in support of 180-second occupation time would be multipath detection/mitigation. Of course, some multipath isn’t going to be detected, but if it is, it’s going to happen in the first few minutes. However, if you’re really concerned about accuracy, you wouldn’t be using GPS to set control in a GPS-unfriendly or marginal environment in the first place!

    In lieu of a 180-second occupation time, I see greater upside in occupying 15-30 seconds twice during the day at time where the GPS constellation is significantly different, but still with six or more GPS satellites with a low PDOP. This would do more for my confidence in the accuracy of the position than one session of 180 seconds.

    Also, there’s discussion of a 180-second session taking five minutes to collect because it rejects measurements that exceed the tolerances set in the receiver. I don’t like this idea. It tells me measurement isn’t stable enough to begin with (unless you have the receiver set to some extraordinarily low tolerance). I’d rather set up over the point, let the RMS values stabilize (should be just a few seconds), and then record a 15-30 second shot.

    Of course, we are only talking about another 2.5 minutes of occupation time, and I’m guessing that most wouldn’t mind spending that on a point designated for secondary control. However, I do see that as the economy continues to put pressure on companies to keep the costs down, that pressure will be put on the field crews to look for time savings. I think occupation times will be one area and not just on establishing control points, but when collecting topo, too.

    I’ll continue on this subject in the next newsletter after discussing more with my colleagues and hopefully hearing comments from you. Also, it’s worthwhile reading a draft document published by the National Geodetic Survey outlining that agency’s guidelines for single baseline RTK users. It discusses, among many other guidelines, the issue of RTK point occupation mentioned above. You can view or download it here.

    Leica/NovAtel Follow-up on RTK Occupation Times

    Following up on my last newsletter, a few folks wrote me about my comment in the Sokkia/Topcon discussion where I noted that Novatel was now owned by Leica and how it would impact the Sokkia/Novatel joint venture named Point, Inc. Several readers pointed out that Leica doesn’t own Novatel, but rather both companies are owned by Hexagon AB of Sweden.

    I understand the technical aspect of one company “owning” another and I certainly misstated that. I was writing more from a strategic view.

    One reader commented that “Both Leica and NovAtel are part of the same group, but they do business at arm’s length, as you would call it. NovAtel supplies Leica with core technology in a standard supplier-buyer relationship.”

    I think it is a little cozier than that. I don’t believe that Hexagon would have touched NovAtel if they didn’t own Leica already, and I think that Leica folks had a lot to do with encouraging the acquisition and were probably intimately involved throughout the due diligence process.

    But I think a good point is made that NovAtel is still committed/focused on being an OEM supplier of precision GNSS receivers. While being owned by the same parent company as Leica hasn’t helped their image as an OEM (original equipment manufacturer) of GNSS receivers for precision (survey and other markets), they are still very active in that business and seem committed.

    A couple of other notes and I’m done with this subject for the time being:

    • If you recall, Spectra Precision is owned by Trimble. It’s not surprising that the Spectra Precision Epoch 25 RTK system was designed using a Trimble GPS receiver. However, the new Spectra Precision Epoch 35 RTK system announced in January uses a NovAtel GNSS receiver. Quite uncharacteristic of Trimble and maybe even unprecedented in their high-precision business (in the past, they’ve used some other GPS receivers in their low-precision GPS products).
    • In other significant NovAtel news, NovAtel announced last week that CEO Jon Ladd is leaving NovaAtel and taking a “strategic advisory role” with Hexagon. Personally, I have a lot of respect for Ladd. After NovAtel suffered through years of finance and administrative type CEOs that floundered, he’s a true GNSS guy and was the right person for the job. He’d been CEO at NovAtel for seven years. Prior to that, he was a key technical executive at Ashtech. Ladd is being replaced by Michael Ritter, who most recently was an executive in Trimble’s Engineering and Construction group.

     

  • A Clear Presentation Danger

    Will Pecha Kucha Rescue Us?

    By Art Kalinski, GISP

    Over the past year I’ve attended over a dozen GIS related conferences and sat through over a hundred presentations, most of them PowerPoint.  Just like the Dilbert cartoon below I’ve reached my limit of poor PowerPoint presentations and I feel compelled to get on my soap box.

    It’s been years since PowerPoint made its entrance but over the past year I still found myself suffering through absolutely horrible presentations. Several years ago there was a Dilbert cartoon in which Dilbert was explaining his side number 397. An audience member, who was actually paying attention, could take it no more and with a scream passed out.  Wally, who had been sleeping, examined him and declared “PowerPoint Poisoning!”  This may be funny but it strikes too close to reality.

    image001

    Over the past year, I’ve attended more than a dozen GIS-related conferences and watched at least a hundred presentations, most of which were conducted in Microsoft PowerPoint. It’s been years since this now-ubiquitous software made its entrance, yet I still find myself suffering through absolutely horrible presentations. PowerPoint has made slide creation so easy that neurotic presenters with no skills, no taste, and no judgment are free to make us squirm in our seats. I’ve finally reached my limit, and I feel compelled to get on my soapbox.

    First, a little history from an old guy who did presentations in the early eighties the hard way: with a grease pencil on overhead projector glass. In the late eighties I was lucky enough to be at a command where the graphics department could create professional-looking transparencies or 35-millimeter slides. The slides looked good, but because of the cost and hassle involved, presenters thought through their points carefully and used the slides sparingly.

    In the early nineties, Harvard Graphics and PowerPoint hit the streets along with LCD projectors, and what should have been a wonderful tool quickly became a curse to many. Edward Tufte, the well-known author and Yale professor of information design, railed against PowerPoint. He used the famous 1869 graphic by Charles Joseph Minard of Napoleon’s march to Moscow as a superb example of the right way to communicate data graphically. This graph is still considered the single best example of elegant simplicity in using a map to display spatial and temporal data.

    Charles Joseph Minard created this "figurative map" of Napoleon's march to Moscow. The image shows the route of the army's march, the temperature, and personnel attrition over time. The brown band represents the men who enter into Russia, and the black band represents those who leave it.
    Charles Joseph Minard created this “figurative map” of Napoleon’s march to Moscow. The image shows the route of the army’s march, the temperature, and personnel attrition over time. The brown band represents the men who enter into Russia, and the black band represents those who leave it.

    That’s how it was done in olden times: slow, deliberate, and thoroughly thought out. PowerPoint has facilitated the exact opposite behavior, with legions of presenters using the high-tech tool as a toy. I remember sitting thorough a presentation given by a senior executive of a major power company in Georgia. It was about a year after Microsoft added sound effects and the bullet fly-in feature to PowerPoint, and this presenter had each bullet fly in with a unique animation and sound effect. After a few minutes, no one was paying attention to the content; the audience chuckled and murmured, trying to predict which effect would come next. The only thing that presenter was missing was a big red nose and floppy shoes.

    Worth a Thousand Words

    In the GIS community, we are especially lucky, because most of our content is a graphic representation of spatial data. I think that’s what attracted me to GIS — its graphic visual nature. In GIS classes I’ve taught, I frequently pointed to a universal human characteristic: our learning, memory, and perception are very much graphically oriented. As an example, I cited the work of scientists who determined that the average person has almost 200,000 discrete human faces in their mental database. That’s pretty amazing, considering the relatively minor differences between faces; we have such discerning powers of observation that even Hollywood impersonators can’t fool most viewers. Of the thousands of Elvis impersonators, many come close to the real thing, but I have yet to see one that’s spot-on.

    So I encourage people to take advantage of that human trait and use graphs, maps, imagery, and photos — not text — as visuals in their communication. Most PowerPoint trainers recommend using very little text, and limiting a presentation to no more than 35 slides and no more that 25 words on any given slide. They also caution to never, ever read the slides aloud. The slides are supposed to enhance the presenter’s presentation, not replace the presenter. My feeling about any presenter that reads his slides aloud is: Save yourself the trip! Stay home and just e-mail me your PowerPoint.

    Good Tools, Bad Results

    One problem with computers is that anyone can produce content that is technically perfect, such as documents, maps, or slides. But technically nice lines and fonts don’t guarantee a good-looking or effective end result. I learned that when I was the GIS Manager for the Atlanta Regional Commission (ARC). In the mid-nineties we started publishing our GIS data on CD so our ARC users could create their own maps. The results were some of the worst maps I’ve ever seen. We quickly learned that when wielded by someone with no cartographic or artistic skills, even sophisticated GIS tools could result in horrid presentations.

    The same held true for Internet projects. In the early years of the Web, the new technology was difficult to master quickly, so we hired a computer firm specializing in Web site creation. I remember asking the company owner about the challenge of finding good HTML programmers. He surprised me with his answer: it was relatively easy to find programmers, but he couldn’t teach them how to be artists and create content that looked good. He said it was easier to start by hiring good artists, and then teach them the programming skills needed to create Web sites.

    And that’s the problem with PowerPoint: Learning the software doesn’t guarantee good presentations. In addition to knowledge of the software, good presentations require artistic talent, a command of the material, and exceptionally good judgment as to how to communicate with your audience.

    I think that many people who overdo PowerPoint do it out of insecurity; they want to show everyone how complicated their job is, and how much stuff they handle. While I was at ARC, I tried countless times to convince our planners that more is less. Frequently they would conduct slide shows containing 80 to 90 slides, with many slides containing more than 100 words each. When these “planning shows” were scheduled, you could see the look of dread on the faces of our board members. The old “I just got a silent-ring cell phone call and I have to leave the room” trick was used frequently.

    Trimming the Fat

    Thankfully, some of these problems have been partially addressed. Good-looking, interactive GIS maps can now be created using ESRI’s MapPublisher, TerraGo’s GeoPDF, or some of the Adobe PDF map formats. All permit the preservation of color schemes, fonts, line widths, symbology, and other cartographic elements in the interactive environments.

    Many companies and conference organizers try to improve the artistic aspect of PowerPoint presentations by requiring presenters to use a standard conference template. But that only standardizes the look, without affecting the content or the way it’s delivered. Now, there’s finally hope that tediously long presentations may get reined in as well.

    There is a relatively new trend you’ve probably heard of called Pecha Kucha (Japanese for “chitchat”). Many pronounce it the way it looks, although the proper pronunciation is “peh chach ka.” This patented presentation method was started by architects Mark Dytham and Astrid Klein. While working in Japan, they would hold shows for young designers. Since they wanted to give many designers the opportunity to show their work, they developed a fast-paced format that limited each presenter to 20 slides and only 20 seconds per slide. The end result was a short presentation: just six minutes and forty seconds.

    Think about the ramifications of this. Just like a “thirty-second elevator pitch,” presenters had to really think through their presentations and distill their material down to only the key points. Currently, most conferences give presenters twenty minutes, plus another five to ten minutes for questions. With a seven-minute limit per session, there can be more time for questions, or for more presentations. The trend is spreading like wildfire: Autodesk is hosting Pecha Kucha nights during conferences, and Bentley and some universities are doing the same. ESRI has tested the format at some local conferences, and the 2009 Annual URISA Conference will have a Pecha Kucha night that I’m looking forward to participating in. My current PowerPoints have fewer than thirty-five slides, and fewer than forty words total, but I’m working to whittle that number down to twenty.

    If you want to learn more, check Google or YouTube, which have many examples to choose from. I promised myself that every time I’m subjected to a poor PowerPoint presentation, I’m going to give the presenter a copy of this article. Maybe you could do the same, and we can collectively raise the bar and see fewer bad presentations in the coming year.

    Well, it’s time to get off the soapbox. So, if you aren’t neurotic, and you’re confident with your knowledge and position, try giving your audience more by giving them less — adopt Pecha Kucha and help cure PowerPoint Poisoning.

     

  • Survey Perspectives: The Beginning of the Battle

    I try to stay current on all the business happenings, product introductions, etc. throughout the year and occasionally report on them.

    Back in my November 2008 column, I discussed the huge price disparity between various real-time kinematic (RTK) systems on the market. One of the products I featured was the Spectra Precision Epoch 25. I featured it because it was being offered at a very low price (comparatively speaking) at approximately U.S. $19,000, including UHF radios for a base/rover configuration. Granted, the Epoch 25 doesn’t offer GLONASS support or support for GPS L2C or L5, but for the price, you couldn’t really argue.

    Spectra Precision is owned by Trimble. Trimble uses the Spectra brand to address the low-price market so they can hold the prices on the Trimble branded systems like the R8 GNSS. One of the ways to create a differentiation between products is to not offer as many features on the low-end product (eg. Epoch 25 vs. R8 GNSS).

    Just last week, Spectra introduced the Epoch 35 GNSS system. It adds a few features like GLONASS, Bluetooth, internal radio, and all-around better packaging. What makes this interesting is the addition of GLONASS to their low-end RTK system. It significantly narrows the feature gap between Trimble’s high-end and Spectra/Trimble low-end RTK systems. Something’s going to give at some point if they keep adding features to the low-end RTK systems. The Epoch 35 GNSS system price is “only” U.S. $32,900, compared to a Trimble R8 GNSS for US$56,000.

    I think what it’s showing us is the trend of high-precision RTK system pricing. The trend is heading downward, and it’s not just due to the economy. The reduction of pricing for RTK systems is going to happen no matter what the economy does (granted the economy may accelerate the trend).

    High-precision RTK systems are going to follow the path of notebook computers with respect to price and features. With notebook computers, each year they are faster, brighter, and packed with new features. Last year’s model is still offered, but at a lower selling price. As RTK system manufacturers attempt to hold the pricing on high-end systems, I think you’ll see more and more features packed into those premium systems, while the low-end systems also become more powerful.

    Sokkia/Topcon

    We haven’t seen the fallout of the Sokkia/Topcon merger yet.

    At this point, Sokkia products are still using Novatel (now owned by Leica) GNSS technology via their joint venture called Point Inc. In 2009, I think you’ll see that starting to change. First of all, you’ll see Sokkia products starting to ship with Topcon GNSS technology. Actually, maybe you won’t see it. Maybe they’ll make the transition transparent … imagine what the local Topcon dealer would do if, all of the sudden, the local Sokkia dealer was selling “Topcon Inside” products with a Sokkia label? I’m sure the Topcon/Sokkia marketing bobble-heads have put some thought into that transition already.

    Also, I’ve written this before and I still believe it. Topcon/Sokkia will be the new Trimble/Spectra Precision. Topcon will address the premium, high-end market while Sokkia will address the entry-level, low-end market. It makes a lot of sense since they are already positioned in the market that way. I could see Sokkia being the entry-level RTK brand that addresses basic RTK functionality while Topcon would provide leading-edge GNSS technology plus other sensor integration such as laser, gyro, inertial navigation, etc.

    On the subject of Sokkia, their GNSSS products appear to offer a very good value. GLONASS is standard in the GSR2700 ISX and it supports modernized GPS signals (L2C and L5), so it’s not affected by the impending (albeit twelve years from now) Civil P/Y phase-out. When compared side-by-side with the Spectra Epoch 35 GNSS, the Sokkia system looks pretty favorable. I haven’t used either one so don’t take that as a stamp of approval. I was just comparing the system specifications.

    The challenge for Sokkia is not one of technical specifications, but one of product distribution and reputation. They just never got any momentum going in the GNSS business. It will be interesting to see how the Topcon/Sokkia merger addresses that.

    So this year will be the beginning of the battle between Trimble/Spectra and Topcon/Sokkia. You have to give Topcon some credit. They’ve really pulled it together this decade and put together a formidable GNSS product line-up. This isn’t to say that Trimble hasn’t been on its game. They’ve been scooping companies right and left to fortify their position.

    Where Does That Leave The Rest?

    Trimble, Topcon and Leica own 75 percent of the world’s high precision GNSS business. Leica doesn’t currently have a dual-brand strategy like Trimble/Spectra and Topcon/Sokkia. One could say that Novatel is their other brand, but Novatel is strictly an OEM manufacturer that doesn’t have a retail presence in the survey/construction market.

    The other 25 percent of the market share is held by Magellan, Javad, Septentrio, Hemisphere, Navcom, and Novariant. They all have commercially viable GNSS technology, but struggle to develop a solid distribution channel to push their products into the survey/construction market. Whereas 10 years ago there were some companies available to partner with that had a strong market presence in the survey/construction market, in 2009 there are virtually none. All of the significant players are paired up and spoken for. It will take some very creative thinking to establish alternative methods of distributing their products into this increasingly competitive high-precision GNSS market.

  • Survey & Construction Newsletter, Late December 2008

    2009 – The Year of the Other GNSS

    Being December, it’s time for my look into next year. It’s become somewhat of a tradition for me and this year is no different. What does 2009 have in store for the GNSS user?

    GPS will push forward in 2009 with the launch of the two remaining IIR-M satellites and launch of the first IIF satellite which will, incidentally, introduce a new civil frequency, L5, to the world. Those are very important milestones, but is it enough to grab the headline as the 2009 GNSS of the Year?

    Nope.

    It’s been a couple of years since I published a column titled “GLONASS — the Comeback Kid”.

    Indeed, at that point the GLONASS program was building steam, albeit slowly. The problem was that although the Russian government was launching six satellites a year, there were still many legacy GLONASS satellites that were being decommissioned. The launch rate was barely keeping up with the rate of attrition. For this reason the GLONASS constellation has fluctuated between 10 and 14 operational satellites for many years. That is changing. In 2009, GLONASS will reach heights we’ve not experienced before.

    With almost all of the legacy GLONASS satellites decommissioned and the Russians still launching new GLONASS satellites at a rate of six per year, it won’t be long before the GLONASS constellation starts to look really, really good. Currently, there are 17 operational GLONASS satellites and three more are scheduled to launch later this month on their annual Christmas Day present to the GNSS world. Assuming the Russians bring them online within 60 days or so after launch, you’ll have 20 GLONASS satellites at your disposal in the first quarter of 2009. There are still some adjustments forthcoming to the constellation due to legacy satellites, according to Sergey Revnivykh of the Russian Space Agency (RSA), so “18 satellites in January/February is nominal.” In other words, we’ll have 20 with a possibility of it dropping to 18.

    Even with 17, the benefits are shining bright for RTK users. Nothing illustrates this better than a couple of plots using mission planning software (provided by Trimble Navigation free of charge via website). These plots are based on my location in Portland, OR USA using an elevation mask of 10 degrees.

    Figure 1: Satellite visibility chart based on using GPS satellites only (plot date is Dec. 15, 2008).

     

    Figure 2: Satellite visibility chart based on using GPS and GLONASS satellites (plot date is Dec. 15, 2008).

    The evolution of GLONASS isn’t a complete surprise. GLONASS was declared operational in 1993, the same year as GPS. However, Russia’s political and economic struggles relegated GLONASS to the back burner and the program began a long, steady decline to a skeleton of what it once was. At its lowest point, in 2002, there were only eight operational satellites.

    As Russia’s economic and political climate stabilized (some say that oil has contributed largely to the revitalization of GLONASS), Russia brought the GLONASS program back to the front burner in 2001 when it announced an ambitious plan to revitalize the program by 2010. The plan was to fly 30 GLONASS satellites by 2010.

    As with many long-term plans, especially a multi-year, publicly financed plan to spend billions, the devil is in the details . . . and execution is the devil. Well, nearly eight years later, the Russians seem to have executed their plan quite well. It wasn’t an easy road with quick results, either. As I mentioned above, the attrition rate of GLONASS satellites was high most of this decade, so they had to be very aggressive in developing and launching new satellites just to keep their head above water.

    This is not to say there haven’t been any problems along the way. I’ve heard several complaints from users of excessive RTK initialization times that were eventually traced back to troubled GLONASS satellite data. For example, a few months ago Topcon issued a Service Bulletin regarding “GLONASS Satellite 9.” The bulletin states that it is “not (currently) broadcasting a P2 signal. This may have an effect on RTK performance. It may cause the receiver to stay in float for a longer period of time.”

    Looking Beyond 2009

    I reported in 2007 that Russia was on the path to bringing GLONASS closer to GPS with respect to compatibility. Currently, GPS uses the CDMA (Code Division Multiple Access) signal-processing scheme while GLONASS uses the FDMA (Frequency Division Multiple Access) signal-processing scheme. They aren’t compatible at all . . . sort of like CDMA (Sprint) vs. GSM (AT&T) networks for mobile phones. They just don’t work together, so manufacturers essentially have to build two receivers (one for GPS and one for GLONASS) in one box. While it’s impressive that manufacturers have been able to squeeze such amazing functionality into small boxes, it’s a complicated design.

    Russia has announced its commitment to support CDMA on the next generation of GLONASS satellites (GLONASS-K). While this will go a long way in making GPS/GLONASS receivers easier/cheaper to design/build, Russia and the U.S. are in discussions to even take it a step further towards interoperability with GPS L5 and the future L1C signal. However, keep in mind the space business works at a different pace than most businesses. It will be well into the next decade before we see any GLONASS satellites broadcasting CDMA signals.

    GLONASS funding is also looking pretty solid at this point. Last September, it was announced that Russian Prime Minister Vladimir Putin signed a budget directive allocating 67 billion rubles (US $2.6 billion) to further develop GLONASS with the majority being steered towards adding satellites. Compare that with the GLONASS budget in 2007 being 9.9 billion rubles ($418.25 million) and 4.7 billion rubles ($200 million) in 2006.

    Congratulations

    Because of GLONASS’s exceptional value to the survey/construction user community in 2009, GLONASS has indeed earned my vote as GPS World magazine’s award of 2009 GNSS of the Year. Remember, the purpose of this particular column is to look forward into the future instead of a year in review. I believe that in 2009 GLONASS will add even greater value to the survey/construction user than we have ever seen.

  • GIS Gives Simulators More Realism

    IITSEC 2008.
    IITSEC 2008.
    What is a GIS guy doing at a training simulation conference? Having a lot of fun — and learning that GIS makes everything better.

    By Art Kalinski, GISP

    Last week I attended the Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC) in Orlando, Florida. It was an international gathering of more than 16,000 attendees, both military and civilian, that featured some 550 exhibits focusing primarily on military-related training and simulation. I know that Geospatial Solutions is a GIS-focused publication and that most of you are GIS professionals, but this conference clearly demonstrated the merging of many disciplines in formerly unrelated communities, including GIS.

    When we hear the word “simulators,” we generally think of flight simulators — and there were many of those on display — but the exhibits also included ground combat, medical, logistic, and cultural immersion simulators. This conference demonstrated the most realistic and up-to-date training and simulation tools available in the world today, and GIS played a fundamental role as the underpinning of many applications. Autodesk, ESRI, and 3D model builders Precision Lightworks all had booths at the four-day event.

    One interesting terminology quirk that I noticed is the difference in usage of the term “database.” We GIS folk generally use the word to describe our vector data and attributes, with imagery as separate layer. But in the training environment, the term is used to describe all the datasets that feed the simulators, including maps, imagery, GIS data, DEMs, CAD drawings, photos, objects, characters, TINS, wireframes, draping textures, skins, etc. The overlap with the video gaming community is significant, but GIS is growing in importance as many applications strive for real-world connectivity.

    Experiencing the Exhibit Hall

    Some of the exhibits showed a significant investment, not just in the technology but in the displays themselves. It was apparent that training and simulation is a big business, with lots of dollars at stake. One exhibitor summed it up this way: “With aircraft and ships costing tens and hundreds of millions each, simulators are a low-cost way of building competence without risking expensive equipment.” The same holds true for soldiers in the field. Actual combat is not the place to conduct training, and everyone is striving to create training that is so realistic that it is indiscernible from actual combat.

    Many exhibitors showcased new display technology, such as very high-resolution projectors from Sony. Most simulators used large flat screens, tripled in some cases to provide panoramic views. One flight simulator used nine separate screens, but even more impressive were large concave screens similar to IMAX. that provided realistic and seamless images, even in 3D.

    Big screen display technology.
    Big screen display technology.

    Some trainers used head-mounted displays (HMDs) for combat action scenarios, but an unusual addition was a 10-foot spherical cage for humans that resembled a giant hamster ball. The subject enters the cage wearing a wireless HMD, and can move in any direction responding to the HMD display and program. The cage was so well designed that it moved with just light finger pressure. Users indicated that getting used to walking or even running in the cage became natural quite rapidly.

    Users indicated that walking in the cage — or even running — became natural quite rapidly.
    Users indicated that walking in the cage — or even running — became natural quite rapidly.

    Some of the exhibits showed significant expense, not just the technology but the displays themselves.  The Augusta Westland helo trainer was one example.

    The Augusta Westland helo trainer.
    The Augusta Westland helo trainer.

    It was apparent that training and simulation is a big business with lots of dollars at stake. One exhibitor summed it up stating, “With aircraft and ships costing tens and hundreds of millions each, simulators are a low cost way of building competence without risking expensive equipment.” The same holds true for soldiers in the field.  Actual combat is not the place to conduct training and everyone is striving to create training that is so realistic that it is indiscernible from actual combat

    I expected to see more simulators that imitated the movement of flight, but as one of the exhibitors told me, the motion and G forces of jet fighters are so great that simulators can’t even come close — so they replicate other aspects of the experience instead. Two motion simulators that were effective included a helicopter flight and gunner simulator, and a Hummer simulator that recreated the motion of a vehicle struck by an improvised explosive device (IED). The shock and rollover over of the vehicle trained soldiers how exit a turned over vehicle while under fire, the goal being to simulate and practice what could happen so there were no surprise situations.

    Vehicle rollover trainer.
    Vehicle rollover trainer.

    Lockheed Martin featured a shipboard engine-room simulator that enabled the training of engineering personnel by simulating various casualties and damage control actions, without risk to people or equipment. The operation was very similar to a video game, with realistic characters responding to the commands of the trainee. As a former Navy Surface Warfare Officer I had to try my hand at the Kongsberg ship bridge simulator. I can attest that not only did the simulator look good, the physics, behavior and reaction of the ship was dead on accurate.

    As a former U.S. Navy surface warfare officer, I had to try my hand at the Kongsberg ship bridge simulator. I can attest that not only did the simulator look good, but the physics, behavior, and reaction of the ship were dead-on.
    As a former U.S. Navy surface warfare officer, I had to try my hand at the Kongsberg ship bridge simulator. I can attest that not only did the simulator look good, but the physics, behavior, and reaction of the ship were dead-on.

    There were numerous small arms trainers and ranges on display that were capable of training individuals, multiple trainees, and even groups acting as teams within a combat environment. I also saw countless examples of wearable gear that permitted simulation of small arms combat using of laser weapons to simulate hits. Numerous urban building mock-up trainers incorporated video displays, realistic sounds, and even explosions and smoke.

    Weapons team training.
    Weapons team training.

    Medical simulation included traumatic injuries and triage scenarios played via video screens. Sickeningly realistic moulage kits imitated all types of injuries, complete with exposed bones and spurting blood. There were many exhibits of peripheral equipment and supplies such a carrying cases, communication gear and even very high quality surface coated mirrors for projectors and displays. One little gem that I hands-on tested at the ESRI booth was a 3D mouse by 3D Connexion.  The “Space Navigator” was the smoothest, most intuitive, most precise, quality feeling mouse I’ve ever used.  I’m getting one.

    3D mouse.
    3D mouse.

    An area I found fascinating — because I didn’t expect to see it — featured exhibitors that focused on human simulation and cultural immersion. DI-Guy and MetaVR were displaying human simulations of crowds that looked realistic and could be programmed to behave in various ways, with each character acting as both an individual and part of the group. The photo shows a Mideast group walking toward an infantry squad while hiding two terrorists in their midst.  Some of the video characters are a little blocky, but new techniques derived from the video gaming industry include draping “skins” on mesh frames instead of boxes or tins. The end result is smoother-looking characters and objects, such as flowing robes.

    Computer generated crowd.
    Computer generated crowd.

    One exhibitor that displayed human motion capture tools used by Hollywood to create animations. They had a young dancer wearing a capture suit whose motion was transferred to a character on a video display. She won the unofficial endurance record since she danced continuously during the four-day exhibit hall operation.

    Human movement capture.
    Human movement capture.

    Another exhibitor, the Tatitlek Corporation, takes cultural immersion to the extreme with live, culturally correct role players that recreate Middle Eastern environments. The live players create the look, sounds, and feel of being in the region, so that it’s not a shock for our troops when they arrive in-theater. Tatitlek displayed one example of their cultural simulations: a sheik’s tent complete with rugs, seating, accessories, and even staged arguments and police intervention.

    Live cultural immersion.
    Live cultural immersion.

    Enhancing Reality with GIS and Imagery

    So how does GIS fit into this community? As I learned from people that have been in this business for years, training simulation first evolved from physical mock-ups to computer-based, CAD-like “cartoon” environments that were only loosely tied to reality. It was considered a challenge to get an image up on the screen that represented reality and make it move around in response to the trainee, but that’s no longer good enough. Now imagery and GIS-referenced data is enhancing the entire environment.

    Lockheed Martin was a big presence at the conference, and created a buzz with flight simulation systems that incorporated photo-realistic and photo-accurate oblique imagery and 3D models into geo-referenced applications that simulate weather conditions and even provide night-time views. This kind of accurate simulation achieves realism not previously seen, and now has captured the attention of mission planners, who have significantly different needs from trainers. The mission planners, as their title implies, plan real missions just before actual execution. For their work they need up-to-date information that is accurate, geo-referenced, and measurable. They cannot tolerate made-up data or imagery — it may be perfectly fine for training, but could be disastrous if relied upon for real execution. The bar has been raised.

    Attending I/ITSEC, I could see the growing convergence of GIS, CAD, BIM models (see my August column for the BIM – GIS convergence), computer display technology, and the training/simulation applications. It’s amazing to watch how everything is coming together. An especially interesting system displayed by the Navy was a flight simulator that collected brain wave data and recorded images of the pilot’s eyeball movements.

    Human factors flight simulator.
    Human factors flight simulator.

    As I viewed this rig I couldn’t help but recall a photo I saw at Moody Air Force Base of an early flight trainer crafted from plywood and broom handles. Imagine how alien this new Navy system would look to the designer of that plywood trainer. I wonder where we will be in 20 more years.

     

  • Survey & Construction Newsletter, Early December 2008

    The GNSS Election ’08: a Victory for the Surveyor

    At the annual ION GNSS conference in Savannah, Georgia, in September, GPS World magazine hosted its third annual Leadership Dinner. Many of the world’s leading GNSS experts attend this dinner. Those experts include research scientists, professors from renowned universities, and heads of companies, as well as influential government representatives and GNSS consultants.

    Earlier this year, Alan Cameron, GPS World editor in chief, was mulling ideas for the theme of this year’s GPS World Leadership Dinner. He said he’d like to dovetail off of this year’s U.S. presidential election. I threw some ideas at him, as did other editors and associates.

    Richard Langley, University of New Brunswick GNSS guru and GPS World Innovation column editor, had this great idea of a two-party system for the 2008 GNSS Election. Thus, the Satellites Party (Blue) and the Signals Party (Red) were born.
    In the election planning stages, an idea for a third party, the Power Party (Green), was floated by Len Jacobson but not enough support was garnered to add it to the general ticket, so to speak. The Power Party was in favor of boosting power on all satellites while keeping the number of satellites and existing signals as they are today.

    As much as the election was designed for entertainment value, the arguments from both parties are real world, and from people waist-deep in GNSS receiver and infrastructure development.

    The Satellites Party position statement: We pledge to implement a total GNSS constellation of 60 satellites, all broadcasting signals that exist on-air today.

    The Signals Party position statement: We pledge to implement full operating capability of L2C, L5, L1C, Galileo’s range of signals, and GLONASS CDMA, broadcast solely from the satellites on orbit today.

    Leading the Satellites Party were Greg Turetzky, SiRF director of marketing, new product technology, and IP; Yatin Acharya, Texas Instruments GPS hardware and software systems product manager; and Per-Ludvig Nomark, NordNav founder and currently a Cambridge Silicon Radio fellow of GPS software. Leading the Signals Party were Javad Ashjaee, Javad GNSS president and CEO, and David Wither, Sarantel Ltd. CEO.

    As you may recall, I was scheduled to moderate the election along with fellow contributing editor Don Jewell. Hurricane Ike had other plans for me. My flight to Savannah was canceled because it was routed via Houston. Alas, ION GNSS 2008 was not meant for me.

    Perhaps it was a blessing in disguise. During the election planning process, I had conferred with Alan privately: “Do I, as a moderator, need to remain objective during the debate?” I queried, knowing full well what the answer would be.

    “Yes, my friend, you do,” said Alan.

    Perhaps that was the beginning of the end for me, at least in my mind.

    Past newsletter columns and other GPS World articles presented way too much incriminating evidence that my objectivity was not just tainted, but downright biased. It reminded me of a writing competition in a journalism class where my paper was promptly returned to me with the words “not objective” scratched in red ink across the entire page by the first evaluator who read it. I was not born lacking neither an opinion nor the desire to express it. I would make a horrible news reporter.

    Back to the Debate

    Javad Ashjaee made some powerful and convincing arguments for the Signal Party. He says the signal quality (read: accuracy) is the foundation from which everything is built.

    “We are the party of building infrastructure. They are party of building toys. They are worried about finding their friends in the middle of downtown New York. We are the party of building roads, generating accurate maps, growing your food by automating agriculture, and synchronizing your power stations. We are even working on automatically landing aircraft to use the air space more efficiently,” said Ashjaee.

    “The latest figure from Col. David Madden, the GPS lead commander, it says costs between $60 million to $70 million to build a GPS satellite, and $200 million is the cost of launching the vehicle, and then add the cost to monitor it and keep it in orbit and a dozen monitoring stations,” Ashjaee continued. “In its lifespan it will cost over $300 million dollars. These guys have no sense for money. They are spoiled brats, especially that Turetzky there (laughs), who want to spend $300 million dollars to play on their cellphones or do those fox games at night in the middle of canyons, of urban canyons, like in New York. I mean, they want to do that with their 99-cent chipsets and they want us to spend $300 million dollars.”

    Hmmm … interesting. Save money by plugging more signals into the same satellites. Makes sense. Leverage off of what you have rather than creating something new. Sort of like adding more memory to the computer you own instead of buying a new computer.

    For the Satellite Party, Greg Turetzky made equally enlightening and convincing arguments. Essentially, quality doesn’t matter if you are unable to benefit from it.

    “We already have an L1 signal. We already have an L2 signal. We already have GLONASS signals. How many signals do we really need? I’m not arguing for one; I’ve got three. I don’t need a whole lot more. What I need, then, is to put satellites in the proper orbits, so that they can access all the different people all over the world who have and need more signals on the same satellites. This way we can actually leverage all the investment that we’ve made in the receivers that we already have.

    “All the people here in the audience, who — I know you don’t own survey receivers, so I won’t go there — but how many of you own a Garmin or a TomTom? Right, or a PND?” Turetsky continued. “How many of you would like if next year it just worked better? You didn’t have to do anything? You don’t have to buy anything new, you don’t have to change any software, just all of a sudden there are more satellites in better orbits all over the world, anywhere you go. It just works better. This is what my party is about — improving the life of every single one of you without costing you an additional penny for everything you’ve already purchased.”

    Fellow Satellite Party member Per-Ludvig Normark chimed in: “I just want to sort of look at, if you don’t see a signal, you don’t see a signal. What is the point of actually throwing in more signals, if you don’t see the first one? I mean it doesn’t really help you. I would argue that you need more satellites to see more signals. That is really what we need. That is what we should focus on.”

    Good points, huh? Especially from Mr. Normark. That theme seems to cross all applications of satellite navigation, whether low-cost vehicle navigation or high-precision construction staking.

    Election Results

    The electorate was offered the opportunity to ask questions of each party.

    Alison Brown of NavSys asked: “Would either party bring forward a collaboration between our American and European brethren in bringing more capability to the end user?”

    Greg Turetzky responded for the Satellite Party responded: “Absolutely. What we’re after is launching more of the satellites that we’ve already designed and built rather than designing and building new things that we’re not quite sure how they’re going to work, whether or not they’re going to be successful or delivered on time, and spending a lot of money to deliver new systems that we’re not really sure what the benefit will be.”

    Representing the Signal Party, Javad Ashjaee rebutted: “Greg, for how many years do you suggest that we freeze and build the same Model T?”

    For a group of rocket scientists, these people are pretty funny. There were 123 delegates in attendance who were registered (attendance confirmed by their dinner order) to cast their ballot. No mail-in ballots were accepted.

    Satellite Party: 62
    Signal Party: 46

    Of course, the election results are being disputed. See the Letters to the Editor section in the December 2008 issue of GPS World. In a move to unify the two parties and soften party boundaries, President-Elect Greg Turetzky has created a new cabinet post, Minister of Accuracy, and offered it to Dr. Ashjaee.

    Epilogue

    The light-hearted debate mixed with real-world issues made this event a one-of-a-kind in the GNSS industry. Although I wasn’t in attendance, I listened to the audio recording and read the transcripts.

    In reality, nations around the world are pushing forth with both the Satellite Party and Signal Party initiatives. There are both more satellites and more signals on the horizon. The hunger for positioning, whether it’s for car navigation, indoor pedestrian navigation, or geodetic surveying, is continuing to grow and push the capabilities of the existing satellite navigation systems. It’s not dissimilar to computing horsepower. It seems that just as we have enough processing power to efficiently run the software we operate, new software packages are introduced that demote our six-month-old computer into the under-powered category.

  • Letters to the Editor: Election Results Disputed

    Editor’s Note: Full transcripts of the pre-election debate are available here: Part 1 and Part 2.

    I hereby notify you that I contest your counting of the ballots of the Signal Party versus the Toy Party. Here are some facts:

    According to your own admission, there were 123 people at the dinner, and you counted 108 votes. The 15 votes that you did not count were obviously cast for me, which makes my count 46 + 15 =  61. My son-in-law voted absentee which you did not count. He officially registered and was part of the meeting. That makes my votes 62, equal to the Toy Party. If you add my own vote, I am a clear winner.

    (I will not bring up the fact that you unfairly did not allow my two grandsons to vote. You cannot use the excuse that they could not write. My daughter could have filled the ballots for them. )

    Even if you don’t count my vote, Tom Hunter was the only legitimate vice president at the meeting. According to the rules, the  VP casts the final vote when votes are equal. He votes for me! You can ask him directly if you don’t believe me.

    Your process was not fair:

    • My investigation reveals that many voters had “hanging chads,” some from Florida;
    • many people voted twice for Greg
    • some dead people voted (I can name them if you want!)
    • You even counted votes of Canadians!
    • The main moderator (Richard) was bribed by Greg! I have photo of Greg buying Coke for Richard and giving him a free Garmin for his car. I copy to Richard and Greg to admit their guilt! Otherwise I will publish the photo of Richard drinking Coke.
    • I may also find your photo drinking Coke.

    This is a serious national security concern. I will bring it up at next year’s meeting and am ready to take it all the way to the Supreme Court if you don’t count the votes fairly!

    There are lots of questions to be answered to the court: Who had custody of the ballots before, during, and after the count? Who were the people who participated in counting the ballots, and what were their qualifications?

    The fact is that the Signal Party won. I demand a re-count!

    — Javad Ashjaee

    Once again, I can only express my deepest disappointment that my colleague would feel the need to drag such a clear outcome through the mud and unnecessary contortion of the legal arena. We all know that does not serve either of our constituencies, but simply enriches the lawyers. I would have expected Mr. Ashjaee to be one of the people who most clearly understood that the will of the people is not subject to the random decision-

    making of the judicial branch. However, as a concilitory gesture to move our great industry forward, I would offer Mr. Ashjaee a seat in the new cabinet as Minister of Accuracy in the Satellite Party government.  

    — President-elect Greg Turetzky

    Editor’s Note: The parties have entered out-of-court discussion to which the magazine is not privy, nor will it entertain any further disputation. Election results stand as announced. However, in the interest of full public disclosure, we wish to allay Minister Ashjaee’s concerns about the identities and qualifications of the ballot guardians and counters.

  • Survey & Construction Newsletter, Late November 2008

    Oh, What to Buy in These Challenging Times

    I receive many requests for advice and/or recommendations from folks who are looking to buy GPS/GNSS equipment for survey and construction. Of course, if they haven’t told me, the first question I ask is, for what type of project are they are planning to use the equipment?

    Some are typical projects like topographical surveys and construction staking, while others are not-so-typical. But no matter what type of project it is, the common denominator is the need for high precision data. It may be real-time or post-processed, networked or base-to-rover, single frequency or dual frequency, single constellation or multi-constellation, machine control or man-pack – it could be any of the above, as well as other configurations. But … no matter what … it has to deliver high precision results.

    Although it may not seem like it, there is a myriad of GPS/GNSS equipment that will provide high precision, or centimeter (cm)-level positioning. To people who are knee-deep in the industry like you and I, it’s a daunting enough task to wade through all the different GPS/GNSS products to find the one that fits the best. To a first-time purchaser, it can be absolutely confusing and mind-numbing to sift through the brochures, Web sites and flyers.

    To further complicate the purchasing process, prices can vary widely. I’ll give you an example. Within the past few months, I’ve been forwarded copies of quotes provided to prospective purchasers of GPS/GNSS equipment and asked to comment on them. You might be amazed at the variation in price.

    Two quotes in particular caught my attention. One was for a Spectra Precision Epoch 25 RTK system. Spectra Precision is owned by Trimble Navigation. The Spectra Precision Epoch product line is distributed by Tripod Data Systems (TDS), which is also owned by Trimble. The other quote was for a Trimble-branded R8 GNSS system. The R8 GNSS is Trimble’s top-of-the-line GPS survey system with all the bells and whistles you can get these days on a GPS survey system. I’ve used the R8 GNSS and it’s a sweet ride.

    Essentially, the Epoch 25 and R8 GNSS can accomplish the same tasks. Both are dual-frequency RTK systems. The Epoch 25 is dual frequency, GPS-only (no GLONASS), and doesn’t support GPS modernization (L2C and L5). The R8 GNSS supports GPS modernization (L2C and L5) and it supports GLONASS. The R8 GNSS is a much sexier package. It is a single, lightweight unit with the radio/GSM modem fully integrated inside a single unit. The Epoch 25 is essentially two pieces instead of one; the receiver itself and the antenna with a cabled connection between the two. There are other subtle differences, but like I said, for the most part they can both accomplish the same tasks and deliver the same precision, although the GLONASS option on the R8 GNSS has some definite benefits in terms of working in areas where the sky is obscured.

    What do you think the price difference is between the two systems?

    The R8 GNSS system quote was U.S. $56,900. The Epoch 25 system quote was U.S. $19,000. That’s a big difference.

     

    This isn’t meant to pick on Trimble, because the entire industry is the same. In fact, there is a saying I’ve heard for years: “If you don’t like today’s price, check again next Tuesday.” That’s especially true in these economic times when there are fewer potential purchasers of GPS/GNSS equipment so manufacturers and dealers must add more incentive to attract buyers.

    When considering purchasing GPS/GNSS equipment, price isn’t the only thing. Local support is an important consideration for most buyers. Local support means technical support as well as sales support (spare parts, etc.). For some buyers who aren’t as technically savvy, it’s obviously even more important. Another variable is that some dealers are more technically competent than others. It doesn’t do you any good if you know more about the system than the local tech representative of the company that sold it to you.

    Which GPS/GNSS Equipment Is Right for Me?

    Answering this one question will help point you in the right direction:

    Do I need the results in real-time, or can I wait until I process the data back in the office (or with a laptop in the field)?

    The answer to this question will make a big difference in the type of systems you should consider. Also, the answer might not be so easy. If you are making a first-time purchase for your surveying firm, you may not know what type of projects your business will be working on a year from now. If you really think you’ll be doing a lot of construction staking and sizeable topo surveys, then it’s pretty clear that RTK is the way to go. If you aren’t sure, then a lower cost pair of single frequency receivers may be the way to go. The return on investment (ROI) for those is pretty quick because they are reasonably inexpensive compared to a full-blown RTK system.

    Systems for post-processing (a pair of single-frequency receivers) can be purchased for well under U.S. $10,000 and deliver centimeter-level horizontal/vertical measurements. Establishing site control is a good example of how those can be used. However, staking of any kind requires real-time kinematic (RTK) positioning. Also, while post-processing can be used for topographic surveys, RTK is a much more efficient tool when the projects are larger.

    Essentially, RTK trades money for time (e.g., you pay more for the equipment but it takes less time to complete the task), while post-processing trades time for money (e.g., you pay less for the equipment but spend more time to complete the task). I know I’ll get a few letters about that because there are some exceptions, but they are generally true statements.
    As you see in the example above in comparing the R8 GNSS and the Epoch 25 system, “full-blown RTK systems” can carry significantly different price tags. These days, there are generally three different levels of RTK survey systems:

    1. L1-only RTK. A relatively new technology, this is an entry-level RTK survey system for under U.S. $15,000. It’s suited well for environments that are ideal GPS conditions, such as wide-open construction sites with a clear view of the sky. The distance between base and rover is generally limited to 10 km, or about (six miles).
    1. Legacy L1/L2 RTK systems. These are the traditional RTK GPS systems like the one I own and like the Epoch 25 system mentioned above. They use L2 in addition to L1, so a longer distance between base and rover is achievable. They are the traditional dual-frequency receivers. They don’t accommodate the new GPS signals being broadcast and planned (L2C and L5), nor can they utilize neither the Russian GLONASS system nor the planned Galileo system. Prices for these systems typically range from U.S. $19,000 to $35,000.
    1. Advanced GNSS RTK systems. These are the state-of-the-art RTK survey systems that utilize all signals being broadcast by GPS and GLONASS, as well as taking into account future GPS (L5), GLONASS and Galileo signals (as much as possible). These bleeding-edge systems will allow you to push the envelope as far as possible with satellite positioning. Due to the additional signals they are able to utilize, you will be able to use these systems at times when the other two can’t perform due to lack of satellite signals. Prices for these systems typically range from U.S. $35,000 to U.S. $60,000.

    It’s tough to cover a topic such as this in a single column, so I’m sure I’ll visit it again. Maybe some of you will email and perhaps I can write about some specific case studies and publish some sort of purchase decision analysis for GPS/GNSS equipment. I’ve also got a few case studies I could include in such a discussion. Given the economic climate, I think this issue will be discussed often throughout 2009, at least.

  • Right Oblique . . . March!

    A complex base-mapping project spawns new techniques — and brings the power of oblique imagery to the military.

    By Art Kalinski, GISP

    When I started basic training and learned the marching command “right oblique march,” little did I know that the term “oblique” would become a capstone of my GIS career. As most readers know, I was a career naval officer who set up the Navy’s first GIS in the mid-eighties. After military retirement and graduate work at the University of North Carolina, I served as the Atlanta Regional Commission (ARC) GIS Manager until I retired early to join Pictometry last year.

    I did so because, much to my surprise, oblique imagery was not being used by the military. In Atlanta, we saw such a dramatic improvement in the effectiveness of first responders using oblique imagery that I felt compelled to help bring this technology to our troops in the field. The first major oblique imagery project that I managed was imaging all Marine Corps Bases in the continental United States.

    The United States Marine Corps contracted Pictometry International and the engineering firm PBS&J to image every USMC base in the continental U.S. with high-resolution ortho and oblique imagery. The imagery was captured from late 2007 through early 2008 and delivered to Marine Corps headquarters for installation in the East and West Coast GeoFidelis GIS systems. Capturing the imagery was uneventful, except for scheduling flights around base exercises and a solving a technical issue that was keeping us from shooting the high-altitude Marine Corps Mountain Warfare Training Center in Bridgeport, California.

    We assisted with the installation of the imagery and software at the East and West GeoFidelis computer centers in a CITRIX environment. After the installation, eighteen user-training classes were held at ten Marine Corps bases.

    Students in the USMC user-training classes learned about oblique imagery, the viewing software, and ESRI ArcGIS integration.
    Students in the USMC user-training classes learned about oblique imagery, the viewing software, and ESRI ArcGIS integration.

    The contract also called for a Public Works Implementation Plan and a Fire Protection Implementation Plan. Several other projects — including a 3D interactive model for security use, an oblique mosaic of a base to replace a large wall photograph lost in a major fire, and a proof of concept demonstrating the integration of oblique imagery with TerraGo GeoPDFs — were also completed.

    Quality Control

    I personally reviewed all the imagery for completeness of coverage, and individual images were spot-checked for image quality. The initial Quantico imagery had too much snow cover to be useful; it was reshot later in the season when the snow had melted. Snow obscures ground details, and the white reflections create excessive contrast that diminishes the visibility of adjoining features.

    All imagery from five directions — north, south, east, west, and ortho — had complete coverage, with the exception of the west view imagery of Miramar. Heavy winds had caused the aircraft to drift off course, resulting in a gap in the oblique imagery from the west view. The other views fully cover the two-square-mile area, and although this falls within quality standards, it will be reshot later this year. This is an error rate of only .02 percent.

    Technical Difficulties

    Oblique imagery had never been collected at the high altitudes needed to photograph the Mountain Warfare Training Center, located about 30 miles east of Yosemite Park. The problem was that the hard drives used to record the imagery couldn’t operate above 10,000 feet. Hard-disk magnetic recorders require a minimal air density in order to separate the record heads from the magnetic media with a microscopic air layer. Low air pressures at 14,000 feet cause the record heads to “crash,” or come in contact with the magnetic surface of the record media. Significant engineering time and experimentation ultimately solved the problem.

    The initial solution was to use pressurized rotating media with high-altitude specifications. This solution functions at up to approximately 16,000 feet above mean sea level, but is not fully reliable. The drives also have slower transfer rates, so more drives were needed in the aircraft for efficient capture. There are other limitations of the rotating technology that are not desirable for a long-term solution, but the capture was accomplished. Engineers are currently testing a more promising technology for high-altitude capture using high-speed, solid-state drive technology. Early examples of this technology proved to be too slow for efficient capture, but new versions of the equipment are showing more promise.

    There were concerns that a CITRIX deployment of the imagery and viewing software could have speed problems. Additionally, the Marine Corps is moving to ArcServer technology, so engineering time was devoted to alternative solutions. Engineers developed thin-client viewing software that could be used if needed.

    Something New: An Oblique Mosaic

    During the course of the contract, a feasibility question was raised: Was it possible to merge individual oblique images to create a base-wide oblique image? This idea was prompted by the loss, during a building fire, of a large traditional aerial photograph. Engineers developed a technique to tile and seamlessly merge multiple oblique photographs to form what looks like a single high-altitude — yet high-resolution — oblique image. This was especially challenging since oblique images don’t edge-match easily; each image has a different perspective, with each pixel being a different size and not rectangular in shape. Those challenges were overcome, and a single base-wide oblique image was created to replace the destroyed aerial photograph. Since the large mosaic was created from many low-altitude, high-resolution obliques, the final large oblique image had very fine resolution throughout.

    3D Models

    One of the deliverables requested under this contract was an interactive 3D model of a high-visibility location in the Washington D.C. area. The location presents security and logistics challenges, so an interactive 3D model will be very useful. The “wire frame” model was created from multiple oblique images by Precision Light Works (PLW) with a semi-automated process similar to stereo pair analysis.

    Once the wire frame is created, the same imagery is automatically draped on the 3D model to create not only a photo-realistic model, but a photo-accurate model — meaning that features are accurately located on the models. The 3D model created by PLW can be used in various software viewers, including Google Earth. Some 3D viewers can also do measurements within the 3D model.

    Public Works Report

    PBS&J worked with Pictometry engineers to develop an implementation plan using oblique imagery for public works applications. One public works application surfaced because there was a need to conduct a survey of runway approaches to determine whether trees had grown into the glide paths or if unauthorized construction had occurred within the glide paths.

    The traditional method to accomplish this task was with survey crews sighting and measuring objects on site — a time-consuming task. The ability to measure heights of vertical features made oblique imagery a natural choice for this application. PBS&J tested the concept and demonstrated the feasibility of doing surveys with the imagery, but more work will be needed to test the accuracy of this method and ultimately receive certification.

    Fire Protection and Emergency Response Report

    Another use of oblique imagery, which received significant publicity, is its use as a planning tool for firefighters en route to a fire. The imagery permits the firefighters to get the lay of the land, measure distances to fire hydrants, and view accessibility.
    Many counties using the oblique imagery have statistically measured a reduction in fire attack time of 60 to 90 seconds.

    This is a significant improvement, and the Marine Corps wanted to provide this advantage to their firefighters. The contract called for a firefighting implementation plan, and we had veteran Battalion Fire Chief Wayne Harper on our team to develop one. Paper reports have always left me cold, so I asked Harper, Why not deliver a functioning laptop, similar to those used by other firefighters, as a deliverable with the plan? We did exactly that, and delivered a fully functional Toughbook laptop configured with oblique imagery, GIS data, and software that could be used in fire trucks for tactical planning. This hands-on working example went further than just a paper report, and should facilitate the installation of similar capabilities on all USMC fire trucks.

    Taking the Lead

    Usually the Marine Corps is at the “tip of the spear” in world conflicts and combat situations, but rarely are they in the lead when it comes to technology. With this oblique imagery project, the USMC has certainly moved to the forefront with oblique imagery technology.

    Although not part of the Marine Corps contract, the development work done to complete the contract underpinned potential war fighter applications. The research and testing clearly points the way to make this technology available to deployed combat units in-theater in an operational mode that could provide near-real-time imagery to ground troops. To this end, Pictometry recently signed an alliance partnership with a leading defense contractor to work on a number of related military projects.

    Photos: Art Kalinski

     

  • Survey & Construction Newsletter, Early November 2008

    Questions from the Webinar:
    Is Dual-Frequency GPS — As We Know It — Becoming Obsolete?

    First of all, I’d like to thank everyone who attended my webinar a couple of weeks ago. I received many, many questions during the presentation and answered a few of these during the event, but there was no way I could handle them. But most were very good questions that deserve answers, so I’ve devoted this column to answering those I couldn’t address at the time.

    Oh yeah, kudos to you who attended; it was the most well-attended webinar to date for GPS World! I really enjoyed it and look forward to the next one in February or so of 2009. The focus on this last webinar was about the Department of Defense decision to discontinue supporting P(Y) on GPS L1 and L2 for civilian users after December 31, 2020.

    You can view the archived presentation here.

    Col. Mark Crews (ret.), former GPS Chief Engineer, is now retired but was kind enough to comment on some of the following questions that were submitted during the webinar, along with Don Jewell, GPS World’s Military and Government editor, and Richard Langley, the magazine’s Innovation editor.

    I should note that it has come to my attention that it is possible the U.S. government might be able to create a “work-around” before 2021 so that the Civil P(Y) sunset date becomes a non-issue. In other words, your legacy dual frequency GPS receivers may end up operating past December 31, 2020 without any problems. Be assured that I will stay on top of this issue and keep you (the readers) up-to-date on any changes regarding Civil P(Y) sunset.

    Question #1: Do you think that there will be a program to convert units to new technology like the television change to digital?

    Gakstatter: With respect to a government subsidy of sorts? I don’t believe there will be.

    Question #2: How do these codes affect the data gathered? And how is the new code going to differ?

    Gakstatter: I assume you’re referring to post-processing. L2C and L5 are completely new codes so more data is being collected. It really won’t affect that way you collect data in terms of the user interface. Length of data collection sessions will probably be shorter.

    A couple of years ago, I wrote an article about the benefit of the new codes. Some of the information in the article is dated now, but it is still fundamentally relevant. You can view the article here.

    Question #3: Explain how civilian receivers such as the Ashtech Z-12 tracks the P(Y) code.

    Gakstatter: I can’t speak specifically as to how Ashtech’s Z-Tracking technology works, but fundamentally I believe it reconstructs the full L2 carrier wavelength in addition to cross-correlating the P-code with L1 and L2.

    Question #4: How will this affect L1-only receivers using base corrections and getting RTK accuracy?

    Gakstatter: It won’t affect L1-only receivers.

    Question #5: Will the new codes be better under heavy canopy or forested areas?

    Gakstatter: L2C and L5 should improve operation in and around trees, but that’s not necessarily a good thing. Don’t be fooled into thinking you can operate reliably at the centimeter level under heavy tree canopy. That will never happen with only GPS. As I stated in the webinar, the real solution for that environment is the integration of other technologies such as pseudolites, inertial navigation, gyros, lasers, etc. I think those technologies will eventually be small and cheap enough to integrate into a GPS/GNSS receiver to allow seamless operation in GPS-impossible environments at the centimeter level.

    Also, more help than L2C and L5 would be the addition of more satellites via GLONASS and Galileo. In this case, I believe that quantity trumps quality. Yes, L2C and L5 are better, but it doesn’t matter how good they are if the receiver can’t track them because of obstructions.

    Question #6: Are these upgradeable or will we have to buy complete new equipment sets?

    Gakstatter: It depends on the product you have and the level of manufacturer support. If you recently purchased a GPS L1/L2 receiver, I would suspect the manufacturer will probably offer an upgrade to at least L2C without having to completely replace your receiver.

    If your L1/L2 is several years old and the manufacturer has discontinued support of that product, then the best you can hope for is some sort of trade-in credit towards the purchase of a new system.

    Question #7: Would a receiver that could track L1, L2, L2C, and L5 obtain a worse fix on just L2C and L5 alone?

    Gakstatter: I have no idea. In theory, it should perform better than the L1/L2 receivers of today because of better code structure, increased signal strength and better ability to mitigate ionospheric error. The frequency separation of L2 and L5 is not as great as that between L1 and L2 (or L5), so the dual-frequency iono correction potentially might not be quite as good. However, there won’t be enough satellites broadcasting L2C/L5 for at least another decade, so we won’t know until then!

    Question #8: Are receiver providers creating units that can be upgraded, or will we be looking at a complete setup replacement (as soon as we are using the stated three codes)?

    Gakstatter: Most major manufacturers of survey receivers have models that can track and use L2C, since that’s a signal that’s being broadcast today. Some say certain models are L5-ready. Likely, those will need to be tweaked with firmware when the actual L5 signal broadcasts.

    Question #9: Is there a simple-to-understand one page document that may explain all of this to a procurement agent so they know what to consider when purchasing GPS equipment? Does the same exist to pass onto engineers?

    Gakstatter: Hmmm … not that I know of, so I’ll try to create one. Email me in a month or so at [email protected].

    Question #10: Will this change have any effect on our equipment before 2010?

    Gakstatter: No. The semi-codeless sunset date is set for December 31, 2020. The only changes happening before 2010 are that a couple of more Block IIR-M satellites will be launched. The IIR-M broadcasts L2C in addition to L1 C/A. Also, in 2009 the first Block IIF satellite will be launched. The Block IIF will broadcast L2C and L5 in addition to L1 C/A.

    Question #11: Will there be new criteria for CORS?

    Gakstatter: The National Geodetic Service (NGS) is updating their GNSS strategy and moving toward supporting all broadcast signals (GPS and others). You may want to take a look at their five year and ten year plans.

    Question #12: Is there likely to be a gradual degradation in the L2 signal availability in the years approaching the sunset date as the older satellites are lost from the system and replaced by the newer birds?

    Gakstatter: I defer to the GPS World’s military and government editor Don Jewell and retired GPS Chief Engineer Col. Mark Crews (ret.). Both say there will be no degradation of the L2 signal, gradual or otherwise.

    Question #13: I had read an article that basically stated more frequencies would yield higher accuracies, especially vertical, over more satellites. Is this an accurate statement?

    Gakstatter: I don’t believe just adding more signals to the same number of satellites will significantly improve accuracy. I believe that more satellites (thus improved satellite geometry) is the best way to improve accuracy, especially vertical. With a full constellation of GPS, GLONASS and Galileo, the number of satellites in view and the PDOP numbers would be incredibly good for high precision users.

    Comment from Dr. Richard Langley, Editor of GPS World’s Innovation column:

    Recall that delta-subscript v = VDOP x delta-subscript p where delta-subscript p is the measurement accuracy (pseudorange or carrier phase), if we can reduce delta-subscript p, then we can also reduce delta-subscript v. So yes, reducing VDOP with more satellites will help more but improvements in signal structure and receiver technology will also help. L5 signals, for example, should have lower multipath contamination and also less noise at low elevation angles.

    Question #14: Why does L5 require a new antenna?

    Gakstatter: It is broadcast on a significantly different frequency (1176.4 5Mhz) than L1 (1575.42 Mhz) and L2 (1227.60 Mhz).

    Question #15: What effect will this have on static processed data?

    Gakstatter: None with respect to the user interface. Behind the scenes, more data is collected and the algorithms of the post-processing software will change significantly. You may see a slight improvement in accuracy. .

    Question #16: So how do you make yourself ready?

    Gakstatter: I’ll be writing more about this in the future. Like I said in my webinar, twelve years from now is a long time. There is no rush to take action.

    Question #17: With reference to my last question (Question #13), presumably no more L2 birds are being launched in the future; what is their expected lifespan?

    Gakstatter: All planned GPS satellites include L2. It’s important to note that L2 isn’t being rendered obsolete. The government is simply reserving the right to change P(Y) on L2 which was originally designed for the military.

    L2C code is the future of L2 for civilian users.

    Question #18: Do you expect the government/public/DOT VRS CORS systems to be upgraded and established with L2C and/or L5 by the sunset date for the L1/L2 signal?

    Gakstatter: I’d refer you to the NGS 10 year plan with respect to CORS. Otherwise, it is up to each individual public or private network (RTK or otherwise) to ensure their network is prepared to handle the sunset date of December 31, 2020.

    Question #19: Let’s say I have my semi-codeless system L1/L2 and everything is fine on January. 1, 2021, but on January 2, 2021 I have an issue. What’s my alternative at that point?

    Gakstatter: You might be able to use L1-only for post-processing, but you may even have an issue with that.

    Question #20: If not planning to already, let listeners know what to spec now in new purchases to ensure equipment will work past 2020.

    Gakstatter: I will work on that.

    Question #21: Do antennas (ex. Trimble Zephyr) become obsolete, or just the receiver board itself? Or do both components become obsolete?

    Gakstatter: It depends on which Zephyr model you are referring to. The newest Zephyr 2 supports:

    • GPS: L1, L2, L5
    • GLONASS: L1, L2, L3
    • Galileo: E1, E2, E5, E6

    This antenna will not be affected. In fact, all GPS dual-frequency antennas of today will be fine in tracking L1 and L2C. Only if you desire to utilize L5 might you need a new antenna.

    Question #22: What happens to the old satellites? Do they just burn up as their orbit degrades and they approach earth?

    Gakstatter: I deferred to the GPS World’s military and government editor Don Jewell and retired GPS Chief Engineer Col. Mark Crews (ret.):

    There are definitely some people who believe that we should de-orbit all our satellites, but unless the satellite is just a few hundred miles above us in a Low Earth Orbit (LEO), it is simply not possible. The GPS satellites orbit in the Medium Earth Orbit (MEO) regime which is 20,200 kilometers (~12,000 miles), on average, above the surface of the Earth. When a satellite becomes too old or fails for some reason, it is boosted into a slightly higher orbit plane which puts it out of the way of any operational GPS satellites.

    In recent years, through solid engineering and strategic thinking, some of the GPS satellites that were still functional, but would have normally been boosted up to a higher orbit, have been left in the operational MEO orbit plane and put to sleep or in standby mode for future use. Just recently some of these older GPS satellites have been reactivated. If we were to allow the satellites orbit to naturally decay from MEO, we will have been in our graves for thousands of years by the time they reach the Earth’s atmosphere, where they would burn-up on reentry.

    Further comment from Dr. Richard Langley:

    There is also the potential for collisions of dead satellites from different constellations (GPS, GLONASS, Galileo, etc.) as a result of the satellites drifting out of their assigned orbit bands over the next 100 years or so. The GLONASS folks are studying this and it was mentioned during Sergey Revnivykh’s presentation at the ION GNSS 2008 CGSIC meeting.

    Question #23: Are there receivers on the market now anticipating the change?

    Gakstatter: Yes, there are many survey receivers on the market right now that can utilize L2C and are prepared for L5. They are typically the premium-priced receivers offered by the manufacturers.

    Question #24: Can you give a brand/model example of a GIS sub-foot receiver that might be affected?

    Gakstatter: Trimble GeoXH, ProXH.

    Question #25: Will L1 receivers using real time reference networks (e.g. Trimble GNSS VRS) be affected?

    Gakstatter: I don’t believe there will be any affect.

    Question #26: How will the CORS network be affected?

    Gakstatter: Please refer to the NGS 10 year plan. I believe the NGS is preparing well for the transition. However, NGS doesn’t have control over most of the CORS stations. That’s a different story.

    Question #27: Can you talk in general about accuracy comparison of the new L2C and L5 capabilities with current legacy RTK accuracy? Will we still need base stations?

    Gakstatter: I touched on this in the webinar a bit. I don’t believe you’ll see a substantial increase in accuracy. I think you’ll see a substantial increase in reliability and robustness of the positions.

    The way to achieve greater accuracy (vertical in particular) is more observations (eg. GLONASS and Galileo).

    Question #28: Would GPS World plan on researching GPS manufacturers and their products that DO NOT support L2C at this time? We sell NovAtel OEMV and they have L2C, but what about the OEM4 we sold two years ago? An article on this would be nice as I can’t find it on their spec sheet.

    Gakstatter: I think this is a good idea and the subject has been raised before. I’m not sure when it will happen, but I believe I will do something along these lines.

    Question #29: Do you have any recommendations for a small startup land survey company? Wait for the new technology to come out or purchase what’s out there now?

    Gakstatter: Well, I think it’s more of a business issue than a technology issue. I’ll make a bunch of assumptions when answering. Personally, I’d try to keep your capital investment as low as possible at this point.

    If you only need post-processing, then a pair of L1-only static receivers is a relatively small investment (well under $10,000). Or, one GPS dual frequency receiver will do, and use an online positioning service like OPUS.

    If you need RTK (real-time, centimeter-level positioning for staking/topo), then the price tag goes up. Do you have access to an RTK network? If so, then you only need an RTK rover and a data plan from a wireless provider like Sprint, AT&T, T-Mobile, etc.

    If you need RTK and no RTK Network access, then you’ll need a RTK reference station also. Again, the price tag goes up. Another piece of equipment to consider (maybe in lieu of GPS) would be a robotic total station.

    It all depends on what kind of projects your company will be involved in the majority of the time.

    Question #30: Comment: GPS tech changes significantly every 1.5 to 2 years, while the useful lifetime of a receiver is on the order of 6 to 8 years. Proper planning will make this a non-issue.

    Gakstatter: In general, I agree there’s plenty of time to plan for the transition. However, the fact is that some GPS equipment purchased in the early 1990’s is still working today and some legacy equipment purchased today will still be operating twelve years from now. This is especially true for survey receivers because the price tag is so high.

    Question #31: Will my L1/L2 receivers still be able to collect L1 data for static computations?

    Gakstatter: I believe they will, but caveat emptor.

    Question #32: If I upgrade to L2C and not L5, what will my limitations be?

    Gakstatter: You will be no worse off than you are today.

    Question #33: Can we expect an increase in vertical positioning accuracy with the new L2C and L5 frequencies?

    Gakstatter: I don’t believe so. For better vertical accuracy, the best bang for your buck will be more satellites (eg. GLONASS, Galileo). However, as stated in the answer to Question #13, there will be some gain in accuracy due to improvements in the code structure of both L2C and L5.

    Question #34: Are the new satellites capable of maintaining our legacy signals, or is it totally out of the question?

    Gakstatter: It’s not that the government wants to eliminate any signals, but rather they reserve the right to alter the military P(Y) signal on L2. After December 31, 2020, it may behave just like it does today or it may not, so yes, they do have the capability to have the satellites behave as they do today.

    Question #35: Comment: I’m like your friend who expected his last purchase to carry him through to retirement. The way my retirement account is growing (negatively) I may still be carrying a range rod when this change occurs.

    Gakstatter: I empathize. Maybe I’ll join you.

    Question #36: will we still need two receivers to use RTK techniques?

    Gakstatter: I also talked about this question during the webinar a bit. Yes, there will still be a need, but I think it will be more ubiquitous than it is today, primarily because of the proliferation of RTK networks and wireless communications technology. Because of this, I think you’ll see the need to operate your own RTK reference station diminishes significantly.

    Question #37: How will this affect my processing software, such as Ashtech Office?

    Gakstatter: Well, you’ll be okay until December 31, 2020. If there is an upgrade path that supports L2C, that might be a good move if your receiver supports L2C.

    Question #38: How much will it cost, upgrading to L5?

    Gakstatter: Please check with your local dealer or the manufacturer of your equipment.

    Question #39: Does adding L1C into the mix have a great advantage?

    Gakstatter: With respect to interoperability with Galileo, yes. With respect to the L1C code itself, it will be superior to its predecessor, L1 C/A, much like L2C/L5 and offer enhanced code and carrier tracking.

    Question #40: With L2C only (no L5), is the cross correlation with the L1 C/A or will there be a new code on L1 as well?

    Gakstatter: There is no new code on L1 at present. The two civilian codes are L1 C/A (the original) and L2C. On Block III GPS satellites, L1C is planned. Basically, a new and improved L1 C/A.

    Question #41: How much is the difference between maintaining the legacy signals and not maintaining the signals?

    Gakstatter: Again, I deferred to the GPS World’s military and government editor Don Jewell and retired GPS Chief Engineer Col. Mark Crews (ret.):

    I assume you are talking about the difference in costs here, but this is really not a question pertinent to this issue, as we are currently not planning on doing away with any current signals. Both the L1 and the L2 signal structure, coded and codeless, will still be broadcast for the foreseeable future. The issue is that, after December 31, 2020, the flex-power capability may cause temporary problems in codeless and semi-codeless civilian receivers for periods of time while the satellites are in flex-power mode.

    However, your question is pertinent in the general sense, as there are new GPS signals and frequencies coming on-board and there are those who believe that some of the old signal structures should be abandoned for the newer more capable signals. So far there have been no decisions made to abandon any of the current signals, only to make them stronger and more robust, with more anti-jam and anti-interference capabilities, which is one of the functions of flex-power that serves the war fighter.

    There is also the possibility that flexible power mode will be modified by 2021 in such a way that it will not cause a L2 phase shift and affect civilian receivers that are using semi-codeless techniques.

    Question #42: Is there a minimum baseline requirement for differential processing (RTK or otherwise) with dual frequency receivers? Will the change from L1/L2 to L1/L5 alter this?

    Gakstatter: The minimum baseline won’t change. There really isn’t one for dual frequency GPS ,although very short baselines sometimes fare better with L1-only rather than L1/L2.

    With regard to legacy L1/L2 vs. L1/L2C/L5, I believe you’ll have more robust solutions with the latter, and longer baseline processing will be enhanced.

    Question #43: If we need dual frequency receivers for survey quality, wouldn’t three frequencies enhance ambiguity resolution and/or accuracy and precision?

    Gakstatter: I believe ambiguity resolution will be enhanced (e.g. quicker and more reliable) due to better ionospheric correction with three frequencies. With regards to accuracy, I don’t see a significant improvement. As I mentioned before, the best way to enhance accuracy/precision (especially vertical) is signals from more satellites (e.g. GLONASS, Galileo, or GPS).

    Question #44: After the sunset date will dual frequency not work at all, or just give bad data? How will we know if the signal has changed?

    Gakstatter: Your receiver won’t be able to correctly resolve the integer ambiguity because of the phase shift. You won’t know until it happens. It’s not a permanent state either. Legacy receivers may work just fine for periods of time, but then may not for periods of time.

    Referring back to the answer to Question #41, it is also possible that the US Government will find a way to resolve this situation where we will not see a phase shift at all.

    Question #45: Will this enhance my L1 handheld accuracy at all?

    Gakstatter: No. L1 C/A will remain the same.

    Question #46: Comment: I know several surveyors who need to hear this conference. It was great. Please publish on the ‘net for access or email to us for distribution. Thank you.

    Gakstatter: Thanks for listening and taking the time to comment. Pls feel free to forward this email or the links embedded in this email to those whom you think are interested. You can take in the webinar via the archived version here.

    If I didn’t fully answer your questions or if it spawned more, please don’t hesitate to email me more questions and comments.