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  • The System: Vistas from the Summit

    “This is an event where one gets one’s goals for the next year.” Paul Verhoef, program director for satellite navigation programs of the European Commission, may have exaggerated for effect, and for the benefit of his audience and hosts at the Munich Satellite Navigation Summit in March. But not by much.

    The conference, now in its eighth year, has assumed increasing importance on the international circuit of GNSS policymakers and communicators. Although with a decidedly European bent, it draws representatives from most if not all systems to mingle and present. A 16-member delegation from China’s Compass system furnished one of the liveliest topics of conversation — and speculation.

    “When we started in 2003, there were many technical conferences on the one side, and we saw a niche for the institutional and political side of satellite navigation,” said Berned Eissfeller of the Institute of Geodesy and Navigation, German Federal Armed Forces University, conference director and host. You can watch video clips of Eissfeller and other speakers.

    GNSS came in for a check-up, a sort of self-examination this time. The 2009 conference was titled “The GNSS Race,” but this year it was “GNSS — Quo Vadis?” The Latin phrase means “Where are you going?” Following program updates, sessions focused on safety-of-life, compatibility, legal/intellectual property, and privacy issues.

    Galileo. Paul Verhoef continued his remarks that open this story. “I have been given [my goal]: Galileo must succeed.

    “You know the world today is not what it was a year ago. It means obviously the financial crisis has had an impact on our economies, on public finance, and therefore I would not be surprised it may leave its mark on satellite navigation. The reason is simple: the systems that are either operating or being deployed are being publicly financed. Galileo is the only system that is financed from a purely civilian budget. All the systems need more than ever to demonstrate their public utility.

    “I put it to you that this is an opportunity. As we’ve already heard, there is much to be gained in this market. After the PC, mobile communications, and Internet, satellite navigation is the next breakthrough technology. There are enormous revenues foreseen and already present in this market. There are many jobs possible for those who want to get it, and we think from the European side we have an enormous chance of capitalizing on this among other things by investing in this technology. Therefore, Galileo- and EGNOS-based innovation is certainly politically of interest.

    “Obviously, it is not a path of roses. There will no doubt be many more critical questions during these days. However, from our side, we have set our goals. I think they are modest, but they are firm. We want to be the second system of choice. At least in the first instance, we will see where we will go after that. Obviously, this is going to cost a bit of time. I shall invite you, if you get impatient, if the public gets impatient, to look at the history of the other systems. Developing and deploying these other systems is costing time.

    “We think that Galileo will meet its deadlines. I think one of the important messages this year, and you have seen it, we are putting things in place. There are contracts in place, there are satellites on order, there are launches on order, there are installations being built — Oberpfaffenhoffen, Fucino, there are others around the world — EGNOS is operational, we’re going to declare the safety-of-life of EGNOS later this year. So we are really moving forward at good speed at the moment.

    “We need to win the hearts of the users, the application providers, and the service providers. At the downstream market is the real challenge for these systems. We need to help do that. We are addressing this among other things by providing a more and more reliable schedule for availability of Galileo and EGNOS services.”

    Galileo ICD Soon. “We are about to publish in the next couple of weeks the so-called signal-in-space Open Service interface control document, which I know a number of you have waited for a long time.

    “We need also to move forward at a political level. In this case, no GNSS system can be credible if it is not backed by a long-term political commitment particularly by its owner. So after the decision of the Parliament and the Council to deploy the system, these two institutions are now clearly called upon to provide us such political long-term commitment that is credible in the eyes of the users.”

    GPS. Anthony Russo, director of the U.S. National Space-Based PNT Coordination Office, said “Keeping cards close to the chest in a competitive situation can well become a liability, creating a future need for a re-work or undoing if you paint yourself into a technological corner.” This appeared to refer to China and its Compass system; information has been singularly difficult to obtain on almost every aspect of this budding constellation.

    Regarding the April 2009 U.S. General Accountability Office report that forecast gaps in constellation availability, Russo stated, “The GAO will revise its report somewhat. They were using a model that was a little too cautious, one used by the [GPS] Wing. But satellites on orbit have been performing past estimated life. Further, we can turn off secondary payloads to conserve energy onboard satellites [and thus extend life] if needed.”

    The next morning, Lt. Col. Liz Roper, Air Force Space Command, gave a status and modernization briefing; the most eagerly awaited development is the launch of the first Block II-F satellite, scheduled for some time in May. She alluded to “a few setbacks” from the August 2009 launch of SVN49 with its well-documented signal problems, but emphasized the episode’s “positive aspects: the relationships we’ve been able to build in seeking solutions to that situation.”

    GLONASS. Grigoriy Stupak, deputy general director and general designer on GLONASS systems, briefed the audience in fluent Russian. For a recent launch update, see story below.

     

    Compass. Two of the Chinese delegates spoke in the opening session. Jiao Wenhai from China Satellite Navigation Office did elaborate the basic principles of the Beidou (Compass) system:

    • openness (“China will widely and thoroughly communicate with other countries on satellite navigation issues.”)
    • independence
    • compatibility (“China will pursue solutions to realize compatibility and interoperability with other satellite navigation systems.”)
    • gradualness.

    He promised an English-language version of the governmental website www.beidou.gov.cn or www.compass.gov.cn “soon.” Wenhai recapped:

    • the frequencies Compass will use: 1561.098, 1207.14, and 1268.52 Mhz in Phase II until 2012; and 1575.42, 1191.795, and 1268.52 in Phase III by 2020.
    • the general development plan: five geosynchronous, five inclined geosynchronous, and four mid-Earth orbit satellites providing a Chinese regional service using mainly Compass Phase II signals; then development of a global service broadcasting mainly Compass Phase III signals from five GEO, three IGSO, and 27 MEO satellites.

    The Chinese speakers displayed a certain disingenuousness in giving verbally and in their slides the location of the January launch, Beidou G1 geostationary satellite, as 160 degrees East, somewhere over the open Pacific. When GPS World pointed out that NORAD satellite tracking shows G1 has been repositioned to a slot at 144.5 degrees East longitude, they huddled for several minutes before stating that yes, it had moved to that position and was undergoing in-orbit testing. That spot was previously occupied by Beidou 1D, apparently decommisioned about a year ago due to power problems. 1D currently orbits in graveyard above geostationary altitude.

    A personage civilly associated with the U.S. Air Force confirmed the actual G1 location to the magazine, and could only speculate that it was more advantageous to Chinese ground control for monitoring and testing. As to why spokespersons misstated the location, that remains inscrutable.

    GLONASS Back in Black

    Three GLONASS-M satellites launched on March 1 are expected to enter service on March 22 and March 30, according to deputy general director Grigoriy Stupak’s statement in Munich. This would bring the constellation, according to his calculations, to 23 operational satellites, though two of those are held in reserve.

    With 21 satellites broadcasting signals, the system claim 98.5 percent global availability. Block 42 (three more satellites) has an August 2010 launch date, and Block 43 one for November 2010. By December, Stupak predicted 24 active satellites on orbit, for 99.5 percent global availability.

    The GLONASS-M satellites have a stated seven-year lifetime. CDMA signals will begin with next-generation GLONASS-K satellites, while FDMA signals continue in parallel. The Russians plan to “reach 5-meter accuracy by 2017, almost equal to accuracy of other GNSS,” and are “paying more attention to differential corrections for integrity monitoring.”

    ICG Questions

    The International Committee on GNSS (ICG) Working Group on Compatibility and Interoperability invites GPS industry members to fill out a questionnaire, provided online in two formats: as a downloadable MS Word document or a PDF.

    The Industry and User Community Questionnaire is designed to obtain worldwide input from industry, academic institutions, and other representatives of the GNSS user community with technical expertise regarding GNSS signals and other system characteristics that aid or hinder the combined use of the signals in applications, equipment, or services. For instance, respondents are asked to grade certain signal characteristics as to their importance in overall interoperability considerations for a particular type of application.

    Respondents are asked to e-mail completed questionnaires to the ICG by May 28.

    To download instructions and the form, go to env-gpsworld-integration.kinsta.cloud/icg.

  • Research and Other Hard Things

    Once again, I reach into the mail bag to pull out this gem, from someone both high up and deep down in administrative matters relating to GPS and other technologies. Herewith:

     

    Two quotes — with Some Accompanying Thoughts

    “If we knew what we were doing, it wouldn’t be called research, would it?”
    —Albert Einstein
    Too often these days we seem driven to produce, forgetting the purpose and value of research and development.  R&D allows us to assess alternatives, identify and mitigate risks, and develop practicable plans to achieve results.  It promotes an iterative process that moves us steadily towards our goals.  It understands both of the 80/20 rules: First, that achieving 80% of the solution usually takes only  20% of allocated resources, and second, that for  any normal program, things will go wrong 20% of the time, so plan accordingly.

    The fact is that we simply do not do enough real research and development.  We have forgotten that the development of products or systems or solutions does not proceed on a single path point-to-point.  It is a continuum that has many ideas going in, a reasonable number that survive intermediate vetting processes, and a manageable field of candidate solutions coming out, from which to pick “the best” alternative.

    We are not comfortable planning for sufficient small failures to ensure that we will not end up with one big one.  We limit the potential value of our successes by not supporting  wild and crazy ideas — even though such ideas may hold the key to real and sustained improvements.  We are too risk adverse.  We are too “results – NOW!” oriented.  We are afraid of failures – even small ones.  We are scared to dream.

    “We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win…”
    —John F. Kennedy

    Sadly, we have lost what made us great in the past: our willingness to take risks, fight for ideals, vigorously debate technical and operational alternatives, and move forward as one — either towards a celebration of a successful conclusion or, if nothing else, a celebration of a significant learning experience from which we can dust ourselves off and do better next time.   We have abandoned our can-do attitude for lists of excuses of why we cannot.  We over-think and over analyze and over-control everything — at every level.  Most seriously of all, we have given up seeing ourselves as one team with one goal.  Everyone’s looking out for themselves — with more time spent looking back in fear than forging new pathways forward.

    The question is not “Where have all the leaders gone?” but rather “As leaders, what can each of us do to re-build and re-energize our risk taking leadership structure, our can-do team culture, our engineering inquisitiveness, our research and development mentality?

    As with all things, the solution starts with the true recognition of the problem.

    Therapy, anyone?

    Sleep was what I wanted, you know what I got.  Wide awake, staying up late, wishing I was not.

  • Expert Advice: Jamming: A Clear and Present Danger

    SallyBasker_120By Sallie Basker

    A packed audience attended the National Physical Laboratory in the United Kingdom for a February 23 meeting titled, “GPS Jamming and Interference: A Clear and Present Danger,” organized by the Digital Systems Knowledge Transfer Network.

    In his keynote address, David Last described a dark, silent and dangerous world without GPS. He regaled attendees with tales from his experience as a GPS forensic expert, assisting the police who beat a path to his door bearing interesting boxes that turned out to be all sorts of jammers: of GNSS, of mobile phones, and of other radio systems. Last pointed to the near future when he believes that spoofers will undoubtedly make an appearance. The defences are limited: detection, prosecution, and the use of alternative sources of positioning, navigation, and timing information, perhaps eLoran.

    His final insight was this: “Navigation is no longer about how to measure where you are accurately. That’s easy. Now it’s how to do so reliably, safely, robustly.”

    Jim Doherty, from the U.S. Institute of Defense Analyses, discussed the use of existing resources for time and frequency backup. Drawing on his experience, Doherty delivered three overarching thoughts:

    • use all available means;
    • re-use existing systems where possible; and
    • produce integrated time and navigation.

    He advised the audience to be conservative with their designs and not to go too close to the boundary conditions. He also noted that there is an important trade-off between independence and cost when considering complementary systems. Finally, he identified a potential need for eLoran to support synchronisation in aviation’s multi-lateration systems.

    Moving on, Alan Grant of the UK General Lighthouse Authorities (GLA) described recent GPS jamming trials. He demonstrated that GPS jamming has wildly different effects, ranging from total denial to hazardously misleading information (HMI). HMI was particularly problematic: it caused the ship’s GPS receivers to report a realistic course and speed well away from the truth that was provided by the GLA’s eLoran system. He noted that the impact depends on the ship’s bridge design.

    Professor and consultant Martyn Thomas spoke on an ongoing Royal Academy of Engineering study on GPS vulnerability, which brings together experts from across the UK and will report in early June.

    This was followed by three presentations on coverage prediction by Robert Watson of Bath University, on interference detection using the U.S. National Geospatial Intelligence Agency’s GPS Jammer Location (JLOC) system by Alison Brown of NavSys Corporation, and on the GNSS Availability, Accuracy, Reliability anD Integrity Assessment for Timing and Navigation (GAARDIAN) interference detection system by Charles Curry of Chronos Technology.

    The conference audience learned that any system can be jammed, that JLOC detects thousands of jammers on a daily basis — nearly all of them unintentional — and that the GAARDIAN system has integrated GPS, eLoran, and clocks for interference detection and mitigation.

    Tom Willems from Septentrio and Peter McIlroy from Raytheon gave a good overview of what can be done with receivers and antennas. Willems focused on pulse blanking and adaptive notch filtering. He saw a clear trend towards hybridization, and confirmed that manufacturers recognise that GNSS is not a golden bullet — they can mitigate some interference but not all.

    Peter McIlroy told listeners to “defeat interference and jamming before you detect it.” This included hybridization with inertial systems, putting some form of barrier between the antenna and the jammer, and the use of controlled pattern-reception antennas. He suggested that controlled pattern-reception antennas might become available for civil use.

    Finally, Paul Groves from the University College London gave a very useful overview on positioning without GNSS. He addressed radio and non-radio systems and presented a fascinating chart that related the various radio systems in terms of range and lifecycle (Figure 1). The message was very timely given the need for complementary systems expressed by all speakers.


    FIGURE 1. Range and lifecycles of current radio systems (courtesy Paul Groves).

     

    I then chaired a lively panel discussion with David Last, Martyn Thomas, Charles Curry, Jim Doherty, and Tom Willems. I led off by focusing the discussion on resilient PNT, referring to the UK Center for the Protection of National Infrastructure’s definition for resilience: the equipment and architecture used are inherently reliable, secured against obvious external threats, and capable of withstanding some degree of damage.

    The panel agreed on the need for hybrid solutions with multiple technologies. It expressed concerns that cheap GPS receivers are components in many systems, and it is too easy to overlook them. Martyn Thomas brought insight from the computing world and noted that we need to avoid single points of failure and to demonstrate independence.

    Do our governments understand and should they do more? The panel thought that different governments are at different points on a journey, and that very few policymakers understand how a loss of GPS impacts critical national infrastructure. It was suggested that the European Union lags behind, due to the focus on Galileo.

    This led to an interesting discussion about economics and funding. Martyn Thomas said that GPS vulnerabilities have grown, and that GPS competitors have disappeared for economic reasons, leaving us dependent on GPS. He pointed out that there are limited mechanisms for sharing funding and questioned whether there are many (any) organisations that are prepared to take the risk.

    If you have limited funding, should it be used for detection or mitigation? The panel agreed that both were needed, but the prevailing view was that mitigation is more important, and that this needs to be supported by human factors activity.

    In Summary. GNSS interference is a real and present danger. It is probably more widespread than generally assumed, and it is here to stay. We can harden our GNSS systems with improved receiver and antenna design, but this will mitigate only some interference, not all. The problem is cost. Cheap — and vulnerable — GNSS receivers will inevitably find their way, unseen, to the heart of our critical infrastructure. We need resilient positioning, navigation, and timing based on independent and complementary systems and sensors. Demonstrating independence is vital but not necessarily straightforward, and true independence costs money. The greatest challenge is helping policymakers understand the risks of relying on vulnerable systems and the need for resilience.

    Finally, I return to Jim Doherty’s overarching thoughts: use all available means; re-use existing systems where possible; and produce integrated time and navigation.

    eLoran, anyone?

    SALLY BASKER is director of research and radionavigation for the General Lighthouse Authorities of the United Kingdom and Ireland.

  • GIS at its Finest: Storm Surge Analysis

    Earlier this week, First American Spatial Solutions (FASS) released a report detailing the risk of 13 coastal cities in the United States to storm surge. It’s a fantastic example of how GIS analysis can be used in a very practical way and on a very broad scale. Did you know that there is a difference (in the insurance company’s eyes) whether an insured residential structure is destroyed by hurricane-force winds or by a storm surge (flooding) caused by the hurricane? The first is covered, while the second might not be.

    I had the opportunity to speak with author Dr. Howard Botts about his report this morning; a link to the 10-minute conversation comes at the end of this article. Dr. Botts is executive vice president and director of database development at First American.

    First of all, from a GIS perspective, FASS has a database of approximately 124 million U.S. parcels. That equates to about 87 percent of the parcels in the United States. FASS estimates there are somewhere around 144.3 million total parcels. Dr. Botts said the biggest challenge for FASS, from a GIS perspective, is automating the management of this massive dataset.

    “There is no national mandate for cadastral or parcel data. So you have about 4,000 different collection units, primarily cities and counties, each of which has their own projection, data standards, different attributes,” said Dr. Botts. “So the first couple of challenges are normalizing the data in terms of projection and coverage and then georectifying it. Some stuff is survey-quality, some stuff is so bad we just put it on the shelf because we can’t use it. Then we also normalize the attributes.”

    “We are using ArcInfo to do the processing and rectification along with some various air photos and other kinds of information and then we manage the entire dataset in Oracle Spatial,” he said. “Literally on a daily basis, we are getting cities and counties feeding us new parcels that have been created. We are constantly refreshing that data and so we do all of that data management within Oracle.”

    The source of the land-elevation and bathymetric data, the heart of the data needed to run analyses such as this, was developed using techniques proprietary to FASS. Dr. Botts wouldn’t go into further detail about the source of the data, but he did say that developing and maintaining that data is more complex than people would think. For example, the bathymetric properties of the sea floor and coast line can change substantially after a storm event, to the point that FASS’s models need to be updated, which they do on an annual basis at the end of April.

     

    Storm Surge Graphic Courtesy of First American Spatial Solutions

    On to the FASS report

    “Retired insurance agent Norman Broussard and his wife Genevieve lived at 154 Brady Drive in Biloxi, Mississippi. Their home, which they built in the 1960s, was just a short stroll from the picturesque Mississippi Sound. When Hurricane Katrina hit, they sought refuge with their daughter. But when they returned, there was nothing left but the concrete slab — the slab the home used to sit upon. The Broussards filed a claim with State Farm. They argued that their home and its contents were destroyed by the hurricane-force winds. State Farm, Mississippi’s largest insurer, denied the claim. The company asserted that the house had been destroyed by the storm surge, or flood, for which coverage was excluded. The Broussards sued. Theirs was the first of the so-called “slab suits” to go to trial. The court’s decision, rendered on January 17, 2007, was a warning to all carriers handling coastal property. In a directed verdict, Judge L.T. Senter found in favor of the Broussards, reasoning that the insurer could not prove what portion of the loss was due to flooding and what portion to wind. The judge then sent the question of punitive damages to the jury, which promptly awarded the plaintiffs $2.5M (later reduced to $1M).”

    After reading the above, you can understand that this is a serious issue involving billions of dollars in residential real estate value — more precisely $234 billion in 13 high-risk U.S. cities, according to FASS. Furthermore, the $234 billion value only includes “current structure value” and does not consider replacement costs, contents, vehicle loss, loss of life or business interruption.

    The 13 cities were determined, using GIS, to be the highest-risk cities to storm surge. The only properties included in the report were those that would be “wet” in a storm-surge event. FASS storm-surge polygons assume the worst-case scenario for each category of hurricane based on the following factors, according to FASS:

    1. Maximum wind speed for each category at time of landfall.

    2. Right-front quadrant of the storm at landfall.

    3. Peak high tide at time of landfall.

    As mentioned previously, FASS has a database of ~124 millions parcels. FASS then identified every property contained within each category of the storm-surge polygon and matched the structure valuation for each residential structure identified.

    The FASS report states that storm surge can damage in several ways:

    1. Water depth. The higher the water level, the greater the damage.

    2. Storm surge velocity. A cubic yard of sea water weighs nearly a ton (1,728 lbs)! Wind-driven water moving at 10-15 mph can cause a tremendous amount of damage.

    3. Transportation of debris. Storm surge can move large objects such as trees, vehicles, boats, and other large objects, and sweep them up against other structures.

    4. Standing period. After the storm surge event, standing water can turn into a toxic lake of debris. Generally, the longer it stands, the more damage is caused.

    Several factors were considered when determining which geographic areas to study:

    1. Hurricane probability.

    2. Vulnerability. Storm surge is most pervasive in coastal areas where there is shallow offshore bathymetry, low-lying coastlines or river estuaries.

    3. Residential density. Most of the nation’s population density is located along the coast.

    Based on the above criteria, FASS selected the following 13 geographic areas:

    *Brownsville, TX
    *Corpus Christi, TX
    *Myrtle Beach, SC
    *Wilmington, NC
    *Long Island, NY
    *Jacksonville, FL
    *New Orleans, LA
    *Charleston, SC
    *Houston-Galveston, TX
    *Tampa, FL
    *Virginia Beach, VA
    *Miami-Dade, FL

     

    The report provides substantial detail on each geographic area such as storm history, number of properties affected, and value of properties affected. For each geographic area, three different maps    illustrate the affected area. Following is an example that shows some of the summary data. Further details of the Gulf-Shores area and the rest of the geographic areas are provided in the full report.

    Gulf-Shores, AL

    Category 5 Exposure: $1,154,467,296.00
    Hurricane Probability: High
    Storm-surge Vulnerability: High
    Residential Density: Medium

    Overhead View of Categories 1-5 Storm Surge Impacting Gulf-Shores and Mobile, AL

     

    The full 18-page FASS report can be downloaded from the FASS website by clicking here. Note that the report is free of charge, but you’ll have to re
    gister before downloading.

    Listen to my 10-minute conversation with Dr. Botts by clicking here. It’s about a 2.5mb audio file.

     

    See you next week.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric

  • Wide Awake Bridging the Gap

    I gave this talk at the Munich Satellite Navigation Summit, in a concluding session titled “Bridging the Gap: A Journalistic View on Progress and Problems of GNSS.”

    __________
    Before telling you what I came here to say today, I should really attempt to answer the question posed by our moderator:Is the world ready for new GNSS applications and services?

    If by that we mean system modernization and newly envisioned applications, the  cutting edge, I say: No. What the world has a crying need for are older GNSS applications and services, ones that we in this room may take for granted, perhaps even view as somewhat passé.  But the vast majority of the world knows nothing of them, and has yet to experience their benefits.

    Giving a journalist’s perspective could be difficult because journalists aren’t supposed to have perspective. Our task is to report the news, just the facts.

    In satellite navigation, governed by physics and radio frequency, one might expect facts to prevail.

    Not always.

    Of course in the technical articles at the core of the magazine, facts rule.

    But in the news that I write, The System, in effect GNSS Quo Vadis — in the news, facts may be in short supply.

    This news is filled with projections, timelines, trends, expectations, a triumph or two, some disappointments, budgets, negotiations, market readiness. Facts come in a distant second.

    Because I cover new developments in constellations on orbit, in ground control and monitoring, in plans and policies and rivalries. All these are created by people.

    By you, in fact. You and your colleagues.  The global navigation community — living and working within the global community.

    These maps, courtesy of Todd Walter and his colleagues at Stanford, show aircraft landing capability and its development over time. You saw them twice yesterday, maybe three times, if you read the magazine in your bag.

    But I use them here to illustrate availability and benefits of high-precision PNT of all kinds.

    Global positioning is available globally, everywhere. Pull out a receiver in the middle of the Sahara, you’ll get a position. What good does that do you, you and your nomad band, if you live in the Sahara?  Not much good, if you don’t have a map, or a frame of reference of some kind.

    If you are a small industry, a local government, a market economy, any manifestation of a society, you need a reference network to get an advantage from your position, no matter how precise.

    And in this white expanse, by and large, no such networks exist. The people living in these white areas are beyond the pale, outside the realm of the marvelous benefits of global positioning.

    Patricia Doherty writes in this magazine, “The leading problems that continue to cripple much of Africa include hunger, extreme poverty, erosion of natural resources, and natural disasters. GNSS can help address these problems.  GNSS applications can increase food security, manage natural resources, provide efficient emergency location services, improve surveying and mapping, and provide greater precision and safety in land, water, and air navigation.”

    This holds true not just for Africa, but across the Southern Hemisphere and swathes of the northern: often known as the Second and Third Worlds – coincidentally, all the white space on this map.

    Why should we, the GNSS community living happily in our First World, the color on the map, care about this? I put it to you that it is in our own best self-interest to do so.

    We’re very busy using GNSS to solve our problems of dense air traffic, and road congestion, hazardous material transport, extracting more from agriculture, finding our way in urban canyons, finding our friends, finding coffee, rescuing people.

    Yes, we have problems.  They may be a higher quality of problem than the rest of the world experiences.

    The rest of the world has poverty, hunger, disease, disaster.  When I hear “Bridging the Gap,” the title of our session – this is the gap that jumps immediately to mind.

    From these problems global conflict arises: terrorism and persistent war in troubling regions.  Violent ideologies are born and nurtured in impoverished circumstances. Our prosperous societies will not know lasting peace until all the world shares some kind of equity in terms of quality of life. There will always be differences. But as long as abject poverty and hunger and unaided disaster exist, as long as a wide, deep gap persists, there will never be peace, lasting peace, or tranquility.

    GNSS can help solve these problems.  But it’s moving awfully slow. These charts don’t have dates, but they imply that by 2018 or 2025 or perhaps later, an aircraft can land with precision in central Africa. The charts don’t offer anything for the people living there at that time.

    How can we ensure that the spread of this marvelous capability applies not only to pilots and passengers, but to all people?

    One way, one suggestion, is to inform our governments and legislators, to insist that every foreign aid program, every school-building project, every hospital or roadbuilding project, shipment of foodstuffs and medical aid, must be accompanied by the hardware for a reference frame, for a regional or portable RTK network, and by the training to install it and maintain it.

    We know that GNSS leverages other technologies. It is a multiplier.

    These regions lack infrastructure. GNSS can provide the infra inside that infrastructure.  A road network, regional development plan, transportation plan to foster local markets and economic development, exploration and extraction of natural resources — these things go better with GNSS.

    For more background on what I’ve discussed, see env-gpsworld-integration.kinsta.cloud/Africa, env-gpsworld-integration.kinsta.cloud/afref, and env-gpsworld-integration.kinsta.cloud/chile.

    Put the power of GNSS where it can do the most good – for everyone.  Let’s remember — and honor — Ivan Getting, the visionary who launched the very first GNSS. His vision: “lighthouses in the sky, for the benefit of all mankind.”

    I’m a journalist. That’s my perspective.
    Thank you.

     

    Sleep was what I wanted, you know what I got.  Wide awake, staying up late, wishing I was not.

  • GPS Gaps Closing Up; West Coast Launches Aired

    Anthony Russo, director of the U.S. National Space-Based PNT Coordination Office, told the Munich Satellite Navigation Summit last month that, regarding the May 7, 2009, U.S. General Accountability Office report that forecast gaps in constellation availability, “The GAO will revise its report somewhat. They were using a model that was a little too cautious, one used by the [GPS] Wing. But satellites on orbit have been performing past estimated life. Further, we can turn off secondary payloads to conserve energy onboard satellites [and thus extend life] if needed.”

    GPS satellites have proven themselves very hardy in space, outlasting their predicted lifetimes. Relying on those longer lives, the Air Force has saved money by replenishing upon need. But the GAO report apparently used more conservative lifetimes for the mathematical models of constellation availability. When those models were projected against the real-world timelines for IIF and Block III, some gaps appeared. Now the GAO and the Wing will re-undertake this exercise, factoring instead the longer lifetimes that the satellites have proved capable of.

    In a hearing before the U.S. Senate Subcommittee on Strategic Forces, Committee on Armed Services on March 10, the following exchange occurred.

    Senator BEN NELSON.  “Ms. Chaplain, last year, the GAO issued a report that resulted in some significant and very negative press coverage about the health and reliability of the GPS system. Could you update us on the GAO’s assessment, now, of the GPS system?”

    Ms. CHAPLAIN (Director, Acquisition and Sourcing Management,
    from the Government Accountability Office (GAO)).
    “Yes. We’re currently conducting a review—a follow- on review. And the two programs we looked at, on the satellite side last year, were the IIF program and the IIIA program. And the IIF program has made some progress, and it’s getting ready for a launch fairly soon.

    “The IIIA program is on—it’s meeting its schedule currently. We still have concerns about the compressed nature of the schedule, and all the very difficult activities ahead for GPS IIIA, but it is not encountering any severe problems at this point.

    “When we look at the health of the Constellation, our findings are pretty similar to last year’s. One thing we weren’t discussing in last year’s report, that should probably brought out more when we talk about it this year, is some of the options the Air Force has available to it to manage GPS if they do have—experience some dips in the Constellation availability. There are options that they have to get through those periods.

    “Our concern is, you just—you don’t want to find yourself in a state where you’re looking at those kind of options; you want to make sure you do everything you can to keep the program healthy, resourced, and on track.”

    A recent story in Spaceflight Now attributes to Gary Payton, the undersecretary of the Air Force for space, a statement that the Air Force currently has under review an option  is to move some high-inclination flights, including future GPS satellite launches from Cape Canaveral to Vandenberg Air Force Base in California.

    “We would like to be able to get to the point where we can project six months or a year down the road that we’re going to have a surge of launches all ganged too close together, that we may pull a GPS launch over to Vandenberg,” the story quotes Payton as saying. “The same rocket and orbitology allows you to launch out of Vandenberg.”

  • On the Edge: Lost Graves, Trail of Tears

    By Steven M. Di Naso, Vincent P. Gutowski, Harvey Henson, and Ryan Leonard

    During the winter of 1838–39, the great Native American Cherokee Nation trekked across southern Illinois, in a forced removal by the U.S. government from their ancestral homeland in Tennessee. Harried, unequipped, and unsupported by their captors, thousands died on the Trail of Tears. Burial records were not kept, and burial locations remain lost to this day. Local history suggests that some Illinois settlers allowed the Cherokee to bury their dead on small plots of land adjacent to their own family cemeteries. One such plot, the Campground Presbyterian Church cemetery near Anna, Illinois, may contain unmarked Cherokee graves.

    Researchers from Southern Illinois University and Eastern Illinois University used GPS to navigate and precisely map probes of a ground-penetrating radar (GPR) instrument in the cemetery. We monumented the geophysical survey grids using real-time kinematic (RTK) DGPS. Site topography was also mapped using GPS, as were the individual cemetery headstones. Adding geographic information systems (GIS) software to our mix to map cemetery headstone distribution and record headstone attributes (dates of death, names), we could determine chronological gaps within the cemetery that coincide with the probable emigration of the Cherokee.

     

    GPR and electromagnetic conductivity produced contour plots of high-resolution magnetic gradient data. Small dipolar anomalies detected are typically related to disruptions within near-surface soil horizons and may correspond to locations of shallow graves: the lost final resting places of many Cherokee.

    By close examination of the geophysical survey data and the anomalies produced from them, we were able to present plausible if not possible locations of several gravesites. However, at this time, and for obvious reasons, the actual location must remain secure and cannot be published.

    The figure below shows a mosaic of amplitude depth slices at .30–.70 meter intervals from processed interpolated 250-MHz GPR profile data. White rectangles denote known graves. Most marked graves were imaged, although some were represented as more subtle anomalies on this display. Some possible unmarked graves were interpreted at UTM coordinates xxxx, yyyy.

     

    The cemetery is within working distance of CORS station ILCB at Southern Illinois University. Two RTK GPS units communicating with the station via CDMA cellular radio used real-time differential corrections along a variable baseline length of approximately 28.5 kilometers, enabling mapping of the site at centimeter-accuracy resolution.

    Survey data were edited, mapped, and analyzed with a GIS. Family genealogy polygons were generated using last names, to produce family distribution plots throughout the cemetery.

     

    Manufacturers

    The study, supported by a National Park Service grant with Southern Illinois University at Carbondale, used two Leica 1250 RTK GPS units, a Leica TC802 robotic total station, and Esri ArcGIS ArcInfo. Equipment was provided by Kara Company of Countryside, Illinois.

  • Augmented Reality and Podcast Interview with Accela

    I recently viewed a TED presentation on augmented reality that was quite impressive. Honestly, I hadn’t heard much about augmented reality by name, I really have been thinking about it for some time. An example is when I’ve been in the field mapping existing features such as irrigation piping or drainage that is eventually filled in and covered by material (e.g., soil, concrete). I’ve often thought how cool it would be if I could wear some sort of high-tech goggles, while GPS mapping, that would allow me to “see” the underground infrastructure as I looked around a city park. In other words, have the existing as-built map in a head-up display in the goggles that is spatially correct.

    I think you’ll see what I mean if you watch the following TED video on Augmented Reality. I guarantee if you watch it, you’ll be glad you spent the eight minutes or so.

    After you view the TED talk, can you imagine how this could be applied to mobile mapping?

    Also, within the last few days, GM made an announcement about its experimentations with head-up displays in automobiles. Essentially, these display (and augment) information on the windshield of the vehicle. I suggest viewing the short two-minute video on Youtube below.

    These are both fascinating looks at how 3D geospatial data is going to be utilized in our everyday lives.

     

    Podcast Interview with Accela

    I spent a few minutes with Brian Weinke, product manager at Accela, about that company’slatest Accela Automation 7.0 and Accela Mobile Office release. Version 7.0 is a “web-based, enterprise application that boosts the ability of governments to automate critical tasks such as permitting; licensing; code enforcement; community planning and development; asset management; and emergency response.”

    You can listen to the ~10 minute podcast here.

    Thanks, and see you next week.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric

  • Letters to the Editor: The Other Shoe

    The Other Shoe

    I read Don Jewell’s column in the March Defense PNT newsletter (see env-gpsworld-integration.kinsta.cloud/othershoe), on the troubling concern about GPS dependency, with considerable interest. I thought he made some excellent points, and, in my capacity as a member of GPS World’s Editorial Advisory Board, I would like to present some further thoughts for consideration.

    I thought Don was pretty fair with General Schwartz’ comments, including the thinly veiled reference to underlying Air Force (AF) motives toward a smaller GPS constellation. However, in addition to focusing on the comments of one senior individual, you might also give some thought to the actions and motives of many in both the civil and military communities who have not only failed to embrace but have also resisted the advancement of a National Positioning, Navigation and Timing (PNT) Architecture and the holistic management framework necessary to implement it.

    After 2-plus years of work by 30-plus government agencies (military and civil), an enterprise-level view of the PNT Architecture was presented to the public at the ION conference in Savannah in 2008. Since that time, discussions regarding its implementation have proceeded very slowly within the government. The Architecture contains all the elements you identify as contributing to the “Perfect Handheld GPS,” though, at the enterprise level, many have not technologically matured to the necessary system-of-systems level that would permit acquisition decisions under government rules. As you know, that will take focused technical analysis and trade studies, as well as further development in some cases to bring promising technologies along. Commercial industry does it faster, but its solutions are in most cases unique and proprietary, and not necessarily applicable for use by government agencies, particularly the military.

    You also advocate for more tightly integrated GPS capability, “resulting in impregnable GPS for all users.” That thought pervades the enterprise PNT Architecture, beginning with its foundational recommendation (that GPS remain the cornerstone) and extending through many of the 18 other recommendations which follow. In the Architecture, however, we put a slightly different twist on the objective of GPS integration.

    We recognize that, while GPS service can be improved by increases in signal power, possible additional signal frequencies, and a larger constellation, GPS itself can never become “impregnable.” Rather, by integrating GPS with augmentations and complements of several different types, our objective is to create continuously available PNT of high precision and fidelity from a variety of sources without regard to which particular source(s) is/are contributing to the solution at any particular point. I like to refer to that as “cloud PNT” with a bow to the recent advancements in “cloud computing.”

    Finally, with regard to eLoran, the PNT Architecture envisioned a place in 2025 for an evolved eLoran-type capability, recognizing the possible value of frequency diversity, higher power, signal penetration, carrying 2D position and precise time, all in a relatively low-cost government-provided LF/MF service. Of course, it would have had to compete with other technology alternatives, but that potential course now seems foreclosed. You make the point that the basis for eLoran is, of course, the Loran-C system whose operation was recently terminated by the Obama Administration.

    The most troubling aspect of that termination was the statement in the Federal Register announcement that the DHS would continue an assessment to determine if a single, domestic system is needed as a GPS backup for critical infrastructure applications at the same time it determined that the continued operation of the viable backup represented by Loran was not necessary.

    Go figure.

    — Jules McNeff
Editorial Advisory Board (since 1990), GPS World

    The Spy

    A prescient reader wrote a comment on the webpage of a recent story about the demise of Loran. See env-gpsworld-integration.kinsta.cloud/rtcm and scroll all the way down. It begins:

     Tso had just installed the last of a series of innocuous-looking boxes in a field some miles to the west of New York City. . . . It, and the other 299 units like it, had a single purpose. It was so simple, and it had been handed like a gift to him by the U.S. government itself. . . . .

    The Other Spy

    I loved your blog, “The Spy Who Loved Me” (see env-gpsworld-integration.kinsta.cloud/wideawake).Please make sure to keep us updated if there is any follow-up from him!

    — Brett Buyan, Santa Barbara, California

     

  • LSAW Conference RTK Network Discussion Roundtable

    A couple of weeks ago, I participated in a roundtable discussion at the Land Surveyors Association of Washington (LSAW) annual conference on the subject of RTK Networks (RTN). Gavin Schrock, administrator of the Washington State Reference Network (WSRN), did a good job of selecting a number of industry folks who’ve got personal experience with RTN to be on the panel.

    I always enjoy listening to heavy RTK users about their thoughts, their procedures and how they arrived at them. We danced around a number of subjects with one being the “RTN’s biggest flaw.” My first thought was the communications link. That always seems to me to be the biggest problem with RTK in general. When it’s not working, the first thing I check is the communications link.

    “Wrong,” said the panel members.

    According to them, the biggest weakness of RTK/RTN is the vertical accuracy. They want vertical accuracy to be equal to horizontal. Duh, why didn’t I think of that? My only excuse is that I’m so used to expecting vertical to be 2x-2.5x worst than horizontal that I already have my expectation set and don’t see it improving until we have a lot more satellites in orbit that will bring very low VDOP values. But I guess if I really think about it, vertical accuracy is the Achilles heel (well, maybe behind the line-of-sight limitation).

    It was great to hear thoughts from real-life RTK users. Two panel members in particular espoused the value of RTK/RTN in their operations.

    Douglas Casement, PLS, a solo land surveyor using a Leica receiver on the Leica Spider Network, talked about the efficiency of RTK/RTN and doing projects in a half-day that would have taken a couple of days using conventional surveying equipment with a two-man crew.

    Mike McEvilly, PLS, works for a surveying/engineering firm in Washington State. He uses the WSRN for RTK corrections. He talked about using RTK on most of their projects in one way or another with the limitation being the vertical accuracy on some projects. I asked him if he had any problems with “brownouts” (lack of satellites), he said he didn’t, but then I found out he is using GPS+GLONASS receivers.

    Larry Signani, PLS, is responsible for the geodetic framework behind three RTNs in Washington State. He talked about how he constrains the networks and ties them into the National Spatial Reference System (NSRS). This is the behind-the-scenes grunt work that really makes an RTN perform. It really makes me wonder how other RTNs handle this.

    Gavin spoke a bit about procedures and the testing they’ve done, with RTN rovers, on NGS Calibrated Baselines (CBL) during the life of the WSRN. They’ve got a myriad of data that they’ve collected and used to develop their RTK operating procedures. It’s fascinating to look at the data they’ve collected…that’s another article altogether, but I will share with you a slide that summarizes their RTK field practice.

     

    There’s always been a lot of discussion about RTK procedures and occupation times. Last year, I wrote an article called “What’s Your Occupation Time?” that garnered quite a few e-mail responses. I want to address that subject again in the next couple of months.

    In the meantime, for those who haven’t read it, an extensive report was published by the UK Survey Association regarding RTK performance and procedures. I highly suggest downloading and reading the report. You can download it by clicking here. I would also suggest downloading and reading the National Geodetic Survey’s User Guidelines for Single Base Real Time GNSS Positioning. Although it doesn’t agree with the UK Survey Association on the time splits (the NGS suggests four-hour time splits) for setting project control, it is the most complete “RTK User’s Guide” I’ve run across. I think it’s a must-read for any RTK beginner as well as a refresher for veteran users.

    I could write a lot more about this, and will over the coming months. I’d love to hear about your RTK field procedures and how you arrived at them. E-mail me at [email protected] and let me know your procedures for setting control and topo surveying.

    Thanks, and see you next time.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric
    Edit: Link updated to User Guidelines for Single Base Real Time GNSS Positioning. Previous link was to a draft version of the document.

  • The Consumerization of GIS: Golf Carts on a Roll

    I had an interesting experience last month that opened my eyes and had me thinking about how consumer electronics has transformed GIS over the last several years. Google Earth was cool when it first came out, but nothing earth-shattering. We’ve been doing the same thing (albeit on a smaller scale) for many years. Although you can debate how much technology it brought to the table, it would be hard to argue that it didn’t bring a new level of digital mapping to the consumer.

    The advancement in GIS technology sort of sneaks up on you in a Moore’s Law sort of way. Every year, the performance of desktop computer and workstation technology improves and sometimes is actually less expensive than the year before. I’ve recently written about this phenomenon when discussing the Apple iPad and the potential impact it (and similar technology) might have on the GIS industry.

    My experience last month has to do with the golf industry. I’ve been involved in the golf industry for about 10 years. There are several uses for GIS and GPS in golf course construction management and operations so I keep my finger on the pulse of that industry.

    You’ve probably seen (and maybe have used) some of the GPS/GIS-based products in golf. Probably the most visible are the handheld GPS receivers targeted for golf and the GPS golf carts that provide a moving map as the golfer drives around the golf course.

     

     

    A quick look at what’s needed with a GPS golf cart system:

    • A detailed map of the golf course is required, typically by GPS mapping all of the features (tees, fairways, bunkers, cart paths, etc.). From the GPS data, a graphical 3D (or 2D) map of the golf course is created.
    • On the golf cart is a touch-screen computer with GPS built in, as well as some sort of communication link (either spread spectrum, Wi-Fi, or GPRS) to facilitate communications from each cart back to the clubhouse. GPS is used to position the location of the golf cart on the map as well as its distance to the green and other features such as ponds and sand bunkers.
    • In the office, a computer with management software is used to view the status/location of each cart and manage the flow of carts on the golf course.
    • A host of other features such as food/beverage ordering, 911, text messaging, etc. are available.

    I was moderately involved with GPS golf cart systems five or six years ago as I had several active golf course projects ongoing.

     

    Part of my deliverable was to provide the GIS vector data that would serve as the base map for the GPS golf cart system. In working with the golf cart systems, there were two weak areas that I could see: hardware reliability and cost.

     

    Hardware reliability: Yesteryear

    The computer hardware used several years ago in GPS golf cart systems to display the map and provide the user interface were essentially early-generation tablet computers. Reliability was an issue largely because these systems were highly customized (e.g., not mass-produced). During that time, notebook computers and LCD displays were still relatively high-end items.

    GPS golf cart systems are subjected to a lot of vibration and shock, and therefore it wasn’t uncommon for three or four carts (out of ~80) to be out of order at any one time.

     

    Hardware reliability: Today

    The sales of notebook computers over the past five years has exploded. More and more, notebook computers are being used in place of desktop computers. This huge boost in production has resulted in widespread mass-production of all types of components used in notebook computers. Consumers are a hard bunch to please, and that is why the major market leaders like Dell, HP, ASUS, Toshiba, etc. have to make their products super reliable. The GPS golf cart systems have benefited tremendously from this growth. Not only are off-the-shelf systems more available and reliable today, but also less expensive than before due to economies of scale.

     

    Yesteryear‘s return on investment

    Years ago, the cost to outfit a fleet of golf carts at the typical golf club was between US$225,000 and $275,000. That is a healthy chunk of change, considering that the entire annual maintenance budget of a typical golf course is only $350,000-$450,000. Mind you, the GPS golf cart generates revenue from rental fees, increased speed of play, etc., but the return on investment (ROI) for a typical golf club was hard to justify since the golf club was left to figure out its financing.

    After factoring in that the useful life of a golf cart is only about five years, you can see that convincing a golf club to invest such a large sum of money would be a difficult task…and it was. Worldwide, only several hundred (maybe a thousand at most) invested in GPS golf cart systems.

     

    Today’s ROI

    In years past, there were only a handful of startup companies designing, manufacturing, and selling GPS golf cart systems. Several of them raised venture capital money (one investor was popular Pro Golfer Greg Norman) and most of them burned through the cash without ever turning a profit.

    As with most emerging markets, industry consolidation is bound to happen. With each GPS golf cart company struggling to survive on its own, the GPS golf cart business was no different. The top three industry leaders (ParView, ProLink, GPS Industries) eventually merged to form GPS Industries LLC.

    GPS Industries then teamed up with Club Car, a leading golf cart manufacturer, and established the Visage GPS Golf Cart System. Last month, they introduced Visage, and I had a chance to go through the system (albeit on a tradeshow floor) with a Club Car product manager.

    With Visage, the cost to the club is a nominal $40/month per cart. For an 80-cart fleet, that’s under $40,000 per year. Visage asks the golf club for a
    five-year commitment, but the golf club has the choice of opting out of the agreement after a year and each year after that with no penalty.

     

     

     

     

    A Perfect Storm

    It was interesting for me when I looked at the Visage after not having much hands-on with GPS golf cart systems in the past several years. It was orders of magnitude better than the previous systems I had encountered. The hardware was cleaner and the software was better from a graphics/functionality perspective.

    The product manager talked about the hardware being customized very little. You’ve seen the improvement in notebook computer screens over the past few years, so you can imagine the display quality of the Visage system. Of course, the computer onboard the golf cart is orders of magnitude more powerful than in previous years.

    I thought to myself, this is the perfect storm of the maturation of computer technology, GPS technology, GIS technology, GPRS/Wi-Fi technology, and 3D graphics technology coming together at the right time to create a fine experience for the golfer with an affordable price tag.

    Each of these technologies has matured considerably over the past few years:

    • Computer technology largely follows Moore’s Law.
    • GPS technology (the systems use a u-blox GPS receiver) using SBAS for GPS corrections instead of setting up/maintaining a GPS reference station and communications infrastructure for broadcasting GPS corrections.
    • GIS technology using publicly available data (e.g., orthophotos and vector data) and leveraging off of the development of 3D GIS tools.
    • GPRS technology (mobile phone networks) has experience tremendous growth in the past few years with very affordable data plans. I neglected to mention that the $40/month per cart cost includes the GPRS data plan. Previous generations of GPS golf cart systems used spread-spectrum or early Wi-Fi technology and required repeaters throughout the golf course to propagate the communications signal.

     

     

    Visage’s GPS golf cart system is only one example of how GIS applications are leveraging of off the rapid developments occuring in consumer electronics. As I’ve written in recent columns, the Apple iPad might be a significant consumer electronic milestone that the GIS industry will leverage off of this year.

    Thanks, and see you next week.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric

  • GPS for GIS Data Collection – 101: Webinar Follow-up

    Thank you for making “GPS for GIS Data Collection – 101” one of the most well-attended webinars we’ve done. It’s the first that was co-hosted by GPS World magazine and Geospatial Solutions online. If you don’t subscribe to my Geospatial Solutions Weekly newsletter, you might want to consider it as I venture into GIS and broader issues that I don’t have the space to cover in this newsletter. Also, the webinar had a record number of sponsors. Thanks to Hemisphere GPS, Laser Technology, and First American. Those folks make it possible for us to bring these webinars to you free of charge.

    As customary, the newsletter after the webinar is dedicated to addressing some of the questions and posting the results from the polls I took during the webinar.

    Poll Results

    I conducted three polls during the webinar. I received some feedback that we aren’t giving folks enough time to respond to the polls. We’ll pay more attention to that in future webinars and allow more time. Following are the results:

    Poll #1: Do you currently use GPS for collecting GIS data?

    Yes:     68.5%
    No:     31.5%

    Total votes: 165

    Poll #2: What accuracy do you require in a GPS mapping system?

    cm-level:     28.4%
    One foot:     10.8%
    Sub-meter:    33.1%
    1-3 meters:    22.3%
    3-5 meters:    4.1%
    5+ meters:     1.4%

    Total votes: 148

    Poll #3: Select the three most important items to you in a GPS mapping system.

    Collect attribute data:    88.1%
    Cost:                71.4%
    Ergonomics:            7.9%
    Photo-geotagging:        19.8%
    Accuracy:            87.3%
    Laser offset points:        22.2%

    Total votes: 126

    Question #1: How many satellites are transmitting and how many are just for replacement purposes?

    Gakstatter: There are 30 operational GPS satellites. Currently, they are configured in a 24-satellite configuration so six of them are orbiting as “back-ups.” There are also three satellites, I believe, that are in inactive reserve that could be brought back into service if required.

    However, as covered in my last three newsletters, the DoD is transitioning the GPS constellation to a 27-satellite configuration to improve satellite visibility to users. The process of transitioning started in January will take up to two years to complete. Please see the following articles for details on the 24+3 configuration:

    The New GPS 24+3 Constellation: What Does it Mean to the Surveying and GIS User?

    GPS 24+3 Configuration: A Closer Look

    The Best and Final Look at the GPS 24+3 Configuration

     

    Question #2: I do have a question, but it will take too long right now. How do I contact you later?

    Gakstatter: Please feel free to e-mail me with questions any time…[email protected]. I learn a lot from your questions.

     

    Question #3: What about use of iPhones or Blackberries with GPS embedded in the device?

    Gakstatter: As smartphones become more powerful and prevalent, I think the use of them for GIS data collection will increase. I have two comments on this:

     

    • To this point, the ability to run GIS data collection software is hit or miss. Some smartphones just don’t have the resources (memory, processing speed) to handle running the more powerful data-collection software on the market. Of course, with technology advancing that may not be as much of an issue in the future, and it’s possible that GIS software manufacturers will write streamlined software specifically for smartphones.
    • The accuracy of GPS receivers built into smartphones will always be pretty rough. I’d put it in the 5+ meter category and I don’t think it will get much better, so adjust your expectation accordingly. However, using Bluetooth you might be able to “tether” the smartphone to a higher performance external GPS receiver.

     

    Question #4: Is there a place for consumer-grade receivers in GIS data collection?

    Gakstatter: Yes, I wrote an article on this last year. You can read it here…

    Consumer-Grade GPS Receivers for GIS Data Collection

    Please don’t hesitate to e-mail me more questions about this that may not be answered in the referenced article. I’ve been thinking about a follow-up article on this subject.
    Question #5: What accuracy would you expect to record from a GPS handheld unit?

    Gakstatter: There are high-performance handheld GPS receivers that can deliver centimeter-level positions and there are consumer-type handheld GPS receivers that delivery 5+ meter accuracy. This is typically a direct relationship between accuracy and cost (you’re not going to get sub-meter accuracy from a $200 receiver).

    The best way to approach this is to decide what accuracy you require (cm-level, one foot, sub-meter, 1-3 meters, 3-5 meters, 5+ meters) and look at the budget you have available. You might want to take a look at the webinar I conducted last year titled “A Buyer’s Guide to GPS/GIS Mapping Equipment” and a newsletter article I wrote around the same time titled GPS Receivers for GIS Data Collection.

     

     

    Question #6: We have a Topcon GMS-2 unit using an exteral antenna on a range pole similiar to one of the pictures you had in the presentation. How does the height of the range pole with the external antenna affect the X-Y position? Or does it? Thanks.

    Gakstatter: The value of the range pole is that it gives the GPS antenna a clear view of the sky (above your head and other local obstructions). It can only improve your X-Y position. I don’t know how many times I’ve seen users hold a handheld GPS receiver up against their chest, effectively eliminating the use (and degrading accuracy) of GPS satellites behind them.

     

    Question #7: For area determination which is preferred: static or dynamic?

    Gakstatter: Personally, I would use dynamic unless you’re talking about a very small parcel of land (less than an acre). I’ve seen a number of reports on this and I believe all of them used dynamic data collec
    tion with pretty reasonable results. In other words, I don’t think static buys you much in terms of acreage precision. However, I’ve been in circumstances where I used a combination of both such as when I know there’s a reasonably straight line between two vertices, but it would be very difficult to walk a direct line between them. In that case, I might use static for that leg of the traverse.

     

    Question #8: I thought that PDOP was Positional Dilution of Precision.

    Gakstatter: Several of you busted me on this. I mis-typed the presentation slide. I wrote Precision Dilution of Precision, which doesn’t make any sense. It should have been Position Dilution of Precision (PDOP). The horizontal component of PDOP is HDOP (Horizontal Dilution of Precision). The vertical component of PDOP is VDOP (Vertical Dilution of Precision).

    Click here for a Wikipedia link that provides a little more information on GPS DOPs.

     

    Question #9: Explain limitations of what type of project you cannot do if not a licensed surveyor.

    Gakstatter: Because local laws vary widely, it really depends on where you are working. Even within a country like the U.S., each state has its own statutes that define the roles of the land surveyor.

    In some areas, activities as simple as GIS data collection must be supervised by a licensed surveyor. In other areas, high-liability activities such as construction staking can be done by virtually anyone.

     

     

    Question #10: Could the steel plate in my head cause multipath or obstruct signals when I use the integrated antenna?

    Gakstatter: I can safely say (tongue in cheek) that in 20 years of GPS product development, conducting workshops/seminars, attending conferences, and performing GPS fieldwork, I’ve never heard this question. I’m speechless.  :-)

     

    Question #11: A presumption that we should avoid is that by default “GIS data collection” implies low accuracy. This is simply not true. Position accuracy is independent of GIS. GIS can handle any level of accuracy the user desires. There is no such thing as a “GIS-grade” or “GIS-accuracy” survey. What relationship does GIS have with accuracy?

    Gakstatter: I think Guest Commentator Craig Greenwald and I covered this well in the webinar, but it’s good to reinforce the point. I cringe when I hear someone say GIS stands for Get It Surveyed because it implies that the quality of a GIS is dependent on accuracy. It’s not. In some cases, +/- 500 feet. accuracy is perfectly fine for analysis in a GIS. The accuracy required by a GIS totally depends on the type of analysis you are conducting. Many surveyors typically think of GIS in terms of a land record (parcel) mapping system, but GIS is used for so much more than that. You don’t need cm-level accuracy to find the optimal location for the next McDonald’s restaurant within a city.

     

    Question #12: Do you plan on conducting a webinar that will discuss strictly GPS, i.e., RTK vs. static, data reduction, post processing, etc.

    Gakstatter: Yes, if you’re not subscribed to the Survey Scene newsletter, please sign up for that here as well as the Geospatial Solutions Weekly newsletter on the same sign-up page. The price is right…free. You can also look at the webinar archives where I have covered some of these subjects before. I’m also scheduled to conduct at least three more webinars this year (next one in May/June – topic not yet determined).

     

    There were many other questions and I’ll continue including answers to them in the mid-March Survey Scene newsletter. Also, I suggest you sign up for my Geospatial Solutions Weekly newsletter (GSS Weekly) as mentioned above as I tackle GPS/GIS-related issues there, too. Next week, in the GSS Weekly, I’ll continue my discussion on the roles of the surveyor and GIS professional.

     

    Thanks, and see you next time.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric