The Mobile Frontier in Field Data Collection

The mobile phone business is going nuts. Makers are introducing powerful phones in groves. The sleek and stylish Motorola Razor is almost an antique now. Apple introduced their new iPhone G3 last week and Sprint is introducing the Instinct later this month, complete with streaming TV service. Blackberry is rumored to be coming out with a touch screen phone for Verizon. Nokia, well, they’re in the process of buying Navteq. Navteq map databases power the leading personal navigation devices (PNDs) like Garmin, Magellan and Navigon among others. ‘Nuff said.

2008/2009 is going to be the year(s) of the smartphone, with manufacturers packing more and more into mobile phones. I saw this at the CTIA Wireless 2008 conference in Las Vegas a couple of months ago. I was blown away by the absolutely huge exhibition booths setup by Nokia, Motorola, BlackBerry/Research in Motion, Samsung, LG, etc. Their booths were like small metropolitan areas within the exhibition center.

Okay, this is cool stuff, but how does this affect my business/organization?

Mobile phones are becoming powerful enough to rival some of the most powerful field data collection devices ever made. Certainly orders of magnitude more powerful than those hand-held bricks we used a decade or so ago.

Granted, most of the emphasis we see on the new mobile phones is geared towards the average consumer: texting, streaming video, e-mail, social networking, and web browsing. That’s where the huge volumes are, and that’s what gets the attention of the handset manufacturers and wireless service providers. Our industry is catching the attention of some software developers who are writing software for smartphones that can be very productive for field personnel. I think it is very early in this game and there is a lot of software yet to be released that will help us become more efficient in the field, though.

One software company who has recognized the potential in this area is a little-known company called Telenav out of Sunnyvale, Calif. Last I heard, they had about 400 people and were rated the no. 1 fastest growing company in Silicon Valley by Deloitte for the period 2002 to 2006 in the technology, media, telecommunications, and life sciences category.

 

You might have used its navigation product. Its flagship GPS navigation software provides the basis for navigation software that Sprint and others sell to their mobile phone customers. It provides many of the same functionality that today’s PNDs provide, such as voice-guided turn-by-turn navigation and points of interest (POI) lookup. The major difference between PNDs and mobile phone applications like Telenav is the up-front cost. PNDs cost from $100 to $1,000, whereas GPS navigation applications for your phone are sold on a subscription basis in the $10 month range. The subscription price in the industry has not settled yet. I think it will end up in the $2 to $3 per month range and/or come bundled with other services like social networking.

To give you an idea of the market reach, Telenav claims their software runs on more than 200 different mobile phones on 12 different wireless carriers in 22 different countries. Competitor Networks in Motion (NIM) claims to have the largest mobile phone subscriber base in North America. They claimed that on the day before Mother’s Day, May 10, it recorded nearly five million server transactions.

Onto Mobile Phone Applications Other Than GPS Navigation

What interests me about Telenav is that unlike most other mobile phone software companies, it is paying a lot of attention to mobile resource management (MRM). In fact, it claims to be the market leader in MRM for mobile phone users. Its flagship product for this market is Telenav Track. Tracking assets and people using GPS is commonplace these days, and there are many, many companies currently offering solutions. Last year, Trimble spent $500 million to acquire @Road, a company specializing in MRM, for example. What differentiates Telenav Track is that all the software runs on mobile phones.

More specifically, I’m really intrigued by the electronic forms aspect of MRM. Essentially, it’s taking a paper form, such as an inspection form, and programming it into an application on a mobile phone. Sound familiar? This is the same concept behind automating field data collection for surveying and construction. Just like 40 years old being the new 30, mobile phones are the new data collectors. Ok, you won’t see them replacing the data collector as you know it today, but I’m seeing a lot more crossover. More traditional field data collectors are now GSM/Wi-Fi capable and more mobile phones are becoming powerful field data collectors.

A case in point: in 2007, the City of New York dedicated 15 inspectors to travel through the city and search for maintenance problems such as potholes, graffiti and excess litter. Traditionally, the city had relied on citizens to report these problem areas, but detailed information and location was often incomplete. The city outfitted the inspectors with BlackBerry mobile phones with custom data collection software installed. The electronic form allows the inspector to record the necessary details while the GPS records the location of the problem area. Unlike traditional data collectors where the data is batched and downloaded later in the day, the data collected on a mobile phone is sent to the server in the office immediately.

The benefits are obvious. The electronic forms control the quality of the data collected by guiding the user through the inspection. The real-time aspect of data collection speeds up the entire process.

Higher quality data + real-time data = better decisions made faster.

Is Dual-Frequency GPS — As We Know It — Becoming Obsolete?

On Friday, May 16, 2008, the Office of Space Commercialization issued a Notice for Public Comment. In it, the U.S. Department of Defense (DoD) proposes to discontinue supporting P(Y) codeless/semi-codeless on both GPS L1 and L2 frequencies on modernized satellites (Block IIR-M, Block IIF and Block IIIA/B/C) beginning December 31, 2020. After 2020, legacy dual frequency receivers may still work, but the DoD would no longer assure that P(Y) power levels and the navigation message would remain the same. Therefore, the civil GPS community has no assurance that legacy dual frequency receivers will operate as before.

Essentially, this means that every dual frequency receiver designed in the 1980’s, 1990’s and many in the early 2000’s would become virtually obsolete. In the interest of disclosure, that includes my own legacy real-time kinematic (RTK) system.

I caution you … it is very easy to rush to judgment regarding this proposal. When I first read it, my first response was “Whoa, dude, no way!” However, it’s important to take a deep breath and work your way through the logic. Your conclusion may be the same as your initial response, but at least you’ve thought it through. That being said, you must also realize that this is the first action, in the history of GPS, which will render a massive amount of GPS equipment obsolete.

What is Codeless/Semi-codeless Processing?

On L1, there is C/A code and P(Y) code. C/A is for civilian use, P(Y) for military use. On L2, originally there was no civilian code, only P(Y) for military use.

Back in the 1980’s, engineers in the commercial sector were trying to figure out a way to utilize L2 because it would significantly increase the receiver’s performance. Some really smart ones figured out how to track the encrypted P(Y) code on L1 and L2. Then they figured out how to cross correlate the measurements on L1 and L2 and voilà, the modern dual frequency receiver was born. This technique is used in virtually all dual frequency equipment sold today in the commercial (non-military) market.

All post-processing and RTK algorithms are based on using codeless/semi-codeless techniques of one sort or another.

Codeless/semi-codeless processing would not have been needed if L2C had been around on the original GPS satellites. In fact, even today there are only six satellites broadcasting L2C. Every satellite launched since 2005 (six of them to date) and each launched in the future will broadcast L2C, so eventually every satellite will.

What’s Being Proposed?

After December 31, 2020, the DoD proposes to discontinue supporting P(Y) on L1 and L2 for the commercial market on all modernized satellites (Block IIR-M, Block IIF, Block IIIA/B/C). Block IIA/IIR satellites will continue to operate as they do today. However, unlike today where Block IIA/IIR account for 25 of 31 operational satellites, the youngest Block IIR satellite will be 16 years old in 2020, if any still exist at all.

The DoD’s proposal assumes that most organizations will have upgraded their GPS equipment by 2020 and will be utilizing L2C (and other modernized signals), so that L1/L2 P(Y) codeless/semi-codeless processing won’t be needed any longer.

In their synopsis, the DoD states that GPS manufacturers have indicated that the user community needs approximately ten years to replace legacy GPS equipment with equipment capable of utilizing modernized GPS signals. You can read the DoD’s full proposal here. It contains a lot of pertinent background information.

Who’s Affected?

Unfortunately for those of us in the survey/engineering/construction/deformation monitoring/high-precision GIS industries, we would be the ones affected the most.

In real terms, this means that any dual frequency receiver not designed to use L2C will essentially become a paperweight after December 31, 2020. The receiver may still work after that date, but there is no assurance it will continue operating properly. The list of receivers affected is quite long and includes models from all major manufacturers, such as Trimble, Leica, Topcon, Magellan (Ashtech/Thales), and NovAtel among others. Check with the manufacturer of your equipment to determine if it is capable of utilizing L2C. If it’s not, then it’s considered a legacy receiver and would become obsolete.

Also, one should be careful and not assume that all receivers sold today are capable of utilizing L2C. Ask your dealer or the manufacturer of the equipment before your purchase.

No L1-only receivers, such as hand-held GPS units, car navigation systems, various tracking devices, GPS-enabled mobile phones, L1-only GPS mapping systems, and timing receivers are affected by this proposal. L1-only RTK receivers are not affected either. None of these use codeless/semi-codeless techniques. The exception is some of the newer GPS receivers designed for GIS data collection at the decimeter (or sub-foot) level. Although not actively marketed as such, these are dual frequency receivers and might be affected if this proposal is carried out.

It doesn’t take long for one to think about the thousands and perhaps tens of thousands of reference stations worldwide that will need to be replaced. Just the United States CORS (Continually Operating Reference Stations) network alone comprises more than 1,000 receivers. Granted, some are modernized receivers that may only need a minor update, but many others are legacy receivers that will need to be replaced or risk obsolescence. Those 1,000+ CORS receivers service thousands of users monthly. In April 2008 alone, the National Geodetic Survey reported that more than one million FTP requests were made for CORS data.

The DoD says that December 31, 2020 isn’t a “hard” date. In other words, GPS equipment using codeless/semi-codeless techniques may work just fine after December 31, 2020. What they are saying is that after December 31, 2020, they won’t guarantee they will not do something that will impact P(Y) code and subsequently prevent your receiver from performing like you’d expect.

Timing Is Everything

I think I understand the DoD’s logic. They are developing these modernized signals (L2C, L5, L1C) that should be commonplace by the time 2020 rolls around. Continued support of semi-codeless would interfere with some new features they want to play with on the military side of GPS. Why support the legacy stuff when the new stuff is better anyway?

The first issue I thought of is what the status of the GPS constellation will be in 2020. Today, GPS users have 31 satellites to work with. As high-precision users, we need every one of those. Just last week, I was stuck in the middle of a GPS fieldwork day waiting for a sixth satellite to come into view so I could continue my RTK work.

The DoD is still only committed to a 24-satellite constellation, but they’ve been spoiling us with 30 or more for quite awhile now. It would be hard to go back.

So, of course, I started doing the math to guesstimate how many satellites will be operational in 2020, based on information provided in the DoD’s proposal and other sources. The DoD’s proposal states that they expect 24 satellites to be broadcasting L2C by 2016 and 24 satellites will be broadcasting L5 by 2018. We know that eight Block IIR-M satellites were built and twelve Block IIF satellites will be built. We also know that, as announced last month, eight Block IIIA, eight Block IIIB and eight Block IIIC satellites will be built. From this information, one can deduce that in 2016 the constellation will look something like this:

• 8 ea. Block IIR-M satellites broadcasting L1 C/A, L2C
• 12 ea. Block IIF satellites broadcasting L1 C/A, L2C, L5
• 4 ea. Block IIIA satellites broadcasting L1 C/A, L2C, L5, L1C

The above lists and the ones following the paragraph below are the civil signals. Of course we can assume that each satellite is still broadcasting military P(Y) code and M-code on L1/L2.

Based on the exceptional life span of legacy Block IIA/IIR GPS satellites, there would still be approximately six to eleven of them still broadcasting L1 C/A code. By 2018 we can deduce that the remaining four Block IIIA satellites and four new Block IIIB satellites will have been launched, giving a total of 24 satellites broadcasting L5. The constellation would look something like this:

• 8 ea. Block IIR-M satellites broadcasting L1 C/A, L2C
• 12 ea. Block IIF satellites broadcasting L1 C/A, L2C, L5
• 8 ea. Block IIIA satellites broadcasting L1 C/A, L2C, L5, L1C
• 4 ea. Block IIIB satellites broadcasting L1 C/A, L2C, L5, L1C

There should also be a handful of remaining Block IIR satellites available for service that are still broadcasting L1 C/A code.

If I’ve done the math right and the DoD keeps this schedule, that’s not bad; not bad at all. In 2016, there would be somewhere between 30 and 35 operational satellites. In 2018, there would be somewhere around 37 operational satellites. In terms of sheer numbers, that’s equal to or better than where we are today.

After working through this, I think it’s obvious that we will be better off than we are today with respect to the satellite constellation. As I’ve written before, triple frequency receivers (L1, L2, and L5) will be far superior to today’s dual frequency receivers that utilize codeless/semi-codeless techniques. If you add Galileo on top of that, it’s a no-brainer. I look forward to the day that I’m in the field and have 20 or more GPS/Galileo satellites in view when just last week I was struggling to find six.

Lastly, in case you missed it ,the DoD stated that if the new satellite schedule were delayed, they would reassess the codeless/semi-codeless sunset date.

It’s All About the $$$

Alas, at the end of the day, this is where it’s going to hurt the user community the most.

I think nearly everyone’s heard of the Spring 2009 sunset date for analog television in the US. On that date, full-power television stations will stop broadcasting on analog channels, rendering analog television sets obsolete. Congress was so concerned about consumer backlash that they are subsidizing analog-digital conversion boxes to the tune of $890 million, based on a price of $50 to $70 each. To put it in perspective, that doesn’t even cover the cost of 3-meter L1/L2 antenna cable.

We are going to get hit in the wallet … hard.

An argument in support of all this states that triple frequency GPS equipment will be much cheaper at that time. I agree it will be cheaper, but we are still talking about tens of thousands of dollars. The survey/engineering/deformation monitoring/high-precision GIS market is relatively limited in size, is highly technical, and requires complex software, training, and technical support. It’s not like spending $150 at WalMart for a Garmin receiver that you can figure out without reading a manual.

Another argument in support of the DoD’s proposal is that 12 years gives us plenty of time to enjoy a solid return on investment (ROI) on our current equipment. While I follow that logic, I’ve seen a lot of GPS equipment in the field that is 15 years to 20 years old. The stuff just keeps working.

I’ve been amazed that my RTK system, based on 12-year-old technology, still cranks up like it did the first time I used it. Maybe it’s more of an emotional feeling than anything else, but as much as I work through the logic, it’s hard to swallow that my $40,000 system has a date with the trash bin.

I know codeless/semi-codeless dual frequency GPS is the core technology for thousands of small to medium sized businesses around the world. Outside of vehicles, GPS equipment may have been the largest capital investment for them. For those who made that purchase in the last couple of years, the codeless/semi-codeless obsolescence is not something they want to hear about even if it is 12 years away.

The U.S. Department of Commerce has done a quick survey and prediction, to get a rough idea of the dollar-value of equipment that will need to be upgraded sometime toward the 2020 time frame. Its figure for the economic impact is $1.3 billion to $1.7 billion dollars per year if semi-codeless were taken away today. That’s the estimated value of at least 200,000 semi-codeless receivers out in the field today, a figure that it
acknowledges to be conservative, by the way.

According to the DoC analyst, if semi-codeless were taken away in five years, in the year 2012, using some growth rates and extrapolating, the estimate would grow to between 373,000 and half a million users worldwide, and the economic loss on a worldwide basis would be between $3.6 billion and $4.8 billion; within the U.S. alone, that portion would be between $1.1 billion and 1.9 billion.

These figures formed the rationale for a proposed decision to push the discontinue date out to 2020, to give manufacturers and the user base adequate time to re-equip for using L2C and L5. Incidentally, a full-length interview on this topic with a senior DoC analyst and advisor to the National Coordination Office for Space-Based Positioning, Navigation, and Timing will appear in the July print edition of GPS World magazine.

I don’t have an answer on the money issue. For the manufacturers and dealers, it’s going to a salesman’s dream, not unlike Y2K and GPS Week Rollover were. For the user community, it’s going to taste sour no matter how it goes down.

You Have Your Chance: the DoD Is Listening

It’s important to note that the DoD is seeking comments from everyone around the globe. The potato farmer in Argentina, the land surveyor in Australia, the geodetic surveyor in the United States, and the engineer in Denmark are all encouraged to comment. GPS is a tool that knows no boundaries.

Col. Mark Crews, the U.S. Air Force GPS Chief Engineer, says the GPS Wing is keenly interested in public comment on the proposal. The Air Force estimates there are approximately 250,000 worldwide users of dual frequency receivers that use P(Y) codeless/semi-codeless.

“We are trying to do everything absolutely the right way in pre-notifying everybody in the world. If anybody has any concerns, please notify us,” said Crews. “We are taking every precaution to transition semi-codeless users to civil coded signals in a stable, measured, and transparent manner by 2020. That’s why we’re taking action now to pre-notify semi-codeless users worldwide and ask for their input by means of the Federal Register’s request for comments.”

Crews further says that the Air Force recognizes that that dual frequency GPS receivers are a “huge business.” It recognizes that these receivers “play an extremely positive role in survey, agriculture, and all high-accuracy augmentation systems. We are bending over backwards until we have at least two other civil signals, being L2C and L5, on 24 satellites in time for people to transition,” he said.

The US Department of Commerce (DoC), on behalf of the DoD, is seeking public comments on the codeless/semi-codeless sunset proposal. Time is short though. You have until June 16, 2008 to submit your comments. I think that’s a mistake; it’s not enough time. They should allow at least 90 days so the word has a chance to spread.

All comments submitted are a matter of public record and can be viewed by anyone at http://www.space.commerce.gov/gps/semicodeless/. As of June 1, 2008, there have been no comments posted and we are half way through the 30-day comment period already.

That concerns me.

Clarifications/Corrections to The Last Column Regarding L5

In my last column I included a listing of satellite models and signals they broadcast. An astute reader was quick to point out two omissions, and I discovered an error as well. First, I neglected to list P(Y) on L1, which is especially important to note, given the subject of this newsletter.

Second, I listed Block I/II/IIA as one group. There are no Block I/II operational satellites any longer. There is only Block IIA/IIR. For complete clarification and for no other reason than I’ve intended to do this for awhile now, I’ve provided a comprehensive table of operational GPS satellites below.

Lastly, I stated last time that there are 26 Block IIA/IIR satellites broadcasting. There are actually 25. Below is a complete list of operational satellites.

PRN	MODEL	OPERATIONAL	PLANE/ SLOT	CIVIL SIGNALS	MILITARY SIGNALS
9	Block IIA	July 20, 1993	A1	L1 C/A	L1 P(Y), L2 P(Y)
31	Block IIR-M	Oct. 13, 2006	A2	L1 C/A, L2C	L1 P(Y), L1M, L2 P(Y), L2M
8	Block IIA	Dec. 18, 1997	A3	L1 C/A	L1 P(Y), L2 P(Y)
7	Block IIR-M	Mar. 15, 2008	A4	L1 C/A, L2C	L1 P(Y), L1M, L2 P(Y), L2M < /td>
25	Block IIA	Mar. 24, 1992	A5	L1 C/A	L1 P(Y), L2 P(Y)
27	Block IIA	Sept. 30, 1992	A6	L1 C/A	L1 P(Y), L2 P(Y)
16	Block IIR	Feb. 18, 2003	B1	L1 C/A	L1 P(Y), L2 P(Y)
30	Block IIA	Oct. 1, 1996	B2	L1 C/A	L1 P(Y), L2 P(Y)
28	Block IIR	Aug. 17, 2000	B3	L1 C/A	L1 P(Y), L2 P(Y)
12	Block IIR-M	Dec. 13, 2006	B4	L1 C/A, L2C	L1 P(Y), L1M, L2 P(Y), L2M
5	Block IIA	Sept. 28, 1993	B5	L1 C/A	L1 P(Y), L2 P(Y)
None	None	None	B6	None	None
6	Block IIA	Mar. 28, 1994	C1	L1 C/A	L1 P(Y), L2 P(Y)
3	Block IIA	April 9, 1996	C2	L1 C/A	L1 P(Y), L2 P(Y)
19	Block IIR	April 5, 2004	C3	L1 C/A	L1 P(Y), L2 P(Y)
17	Block IIR-M	Nov. 13, 2005	C4	L1 C/A, L2C	L1 P(Y), L1M, L2 P(Y), L2M
None	None	None	C5	None	None
29	Block IIR-M	Jan. 2, 2008	C6	L1 C/A, L2C	L1 P(Y), L1M, L2 P(Y), L2M
2	Block IIR	Nov. 22, 2004	D1	L1 C/A	L1 P(Y), L2 P(Y)
11	Block IIR	Jan. 3, 2000	D2	L1 C/A	L1 P(Y), L2 P(Y)
21	Block IIR	April 12, 2003	D3	L1 C/A	L1 P(Y), L2 P(Y)
4	Block IIA	Nov. 22, 1993	D4	L1 C/A	L1 P(Y), L2 P(Y)
24	Block IIA	Aug. 30, 1991	D5	L1 C/A	L1 P(Y), L2 P(Y)
None	None	None	D6	None	None
20	Block IIR	June 1, 2000	E1	L1 C/A	L1 P(Y), L2 P(Y)
22	Block IIR	Jan. 12, 2004	E2	L1 C/A	L1 P(Y), L2 P(Y)
10	Block IIA	Aug. 15, 1996	E3	L1 C/A	L1 P(Y), L2 P(Y)
18	Block IIR	Feb. 15, 2001	E4	L1 C/A	L1 P(Y), L2 P(Y)
32	Block IIA	Dec. 12, 1990	E5	L1 C/A	L1 P(Y), L2 P(Y)
None	None	None	E6	None	None
14	Block IIR	Dec. 10, 2000	F1	L1 C/A	L1 P(Y), L2 P(Y)
15	Block IIR-M	Oct. 31, 2007	F2	L1 C/A, L2C	L1 P(Y), L1M, L2 P(Y), L2M
13	Block IIR	Jan. 31, 1998	F3	L1 C/A	L1 P(Y), L2 P(Y)
23	Block IIR	July 9, 2004	F4	L1 C/A	L1 P(Y), L2 P(Y)
26	Block IIA	July 23, 1992	F5	L1 C/A	L1 P(Y), L2 P(Y)
None	None	None	F6	None	None

So, You’ve Been Hearing About L5

It seems in the world of high-precision GPS, there is always something new to consider. A new satellite launched … a new signal being broadcast … a new whiz-bang product introduced.

In fact, engineers are designing GNSS receivers to be “compatible” with signals that aren’t even being broadcast yet. Even more interesting is that salespeople are selling GNSS receivers that are “capable” of receiving these signals that aren’t being broadcast yet, and satellite navigation systems that don’t even exist yet, such as Galileo.

The third civil GPS signal, L5, has been in the news lately, so hearing about it has probably got your antenna up. First of all, let me clarify that a useful L5 signal is still years away – several years.

The L5 news you’ve been hearing about lately is a test of the L5 frequency from a modified Block IIR-M satellite built by Lockheed-Martin last year. For ~$6 million, Lockheed modified one of the Block IIR-M satellites to broadcast some test data on the L5 frequency (1176Mhz). The modified Block IIR-M satellite is scheduled to launch next month.

However, the L5 test data being broadcast won’t be usable by your GNSS receiver that is capable of receiving GPS L5. In fact, I’m almost certain that even if you purchased an L5-capable GNSS receiver today, a serious software update (if not hardware) will be required even when usable data is eventually broadcast on L5.

For a quick review, let’s summarize which satellite models are/will broadcast the various signals:

• Block I/II/IIA (26 are broadcasting) – L1 C/A, L2 P/Y
• Block IIR-M (six are broadcasting, two remain to be launched) – L1 C/A, L2 P/Y, L2C
• Block IIF (12 are planned, first launch planned in 2009) – L1 C/A, L2 P/Y, L2C, L5
• Block IIIA (eight or possibly 10, first launch planned for 2014) – L1 C/A, L2 P/Y, L2C, L5, L1C

The first Block IIF is scheduled for launch in 2009. At an aggressive launch rate of three per year, all twelve wouldn’t be in orbit until the end of 2012. Even then, we’ll only have twelve satellites broadcasting on L5. Users will derive some benefit from those twelve, but nothing like you would with a full constellation.

Since there are only twelve Block IIF satellites planned, having more than twelve satellites broadcasting L5 means we’ll have to wait for the Block III satellites to be launched. This could go well into the next decade as the U.S. Air Force awarded the contract to Block IIIA satellites to Lockheed just last week, with a first launch optimistically scheduled for 2014.

Besides launching satellites, there are many other L5 technical issues that need to be addressed, such as the control segment infrastructure (software and hardware). There are also significant non-technical issues, money being a big one. Launching satellites is an expensive endeavor; up to $100 million per launch is the number commonly referred to. This is one major reason why GPS satellite launch schedules are a moving target. As much as I’d like to see more satellites in orbit, I understand why the bean counters might want to push out GPS satellite launches for a year when there are 31 operational satellites today, the most ever in history. For that reason, I wouldn’t care to place a bet on where we’ll be with L5 four years from now anymore than I’d bet on where Garmin stock will be four years from now.

What’s so cool about L5 anyway?

Setting launch schedules, infrastructure development, and funding aside, L5 offers some really significant benefits to the high-precision user. First and most significant is that the days of worrying about ionospheric activity will be over. At 1176 Mhz, the L5 frequency separation from L1 (1575Mhz) is significant enough that the ability of your receiver to directly mitigate the ionospheric refraction will render the iono beast essentially harmless.

If you’re relatively new to GPS (in the last six years or so), you will experience the iono beast in the coming years before L5 is ready to help. The current solar cycle has just started and will continue for eleven years. It will peak around 2011 to 2012. The next solar cycle’s affect on GPS is worthy of a newsletter column by itself, and I will have one in the coming months.

Another benefit of L5 is that its broadcast strength is about four times stronger than L2C. A stronger signal combined with a superior code structure means that you’ll get more robust performance in tough GPS conditions. That’s great news for high-precision users working in marginal GPS conditions.

Breaking News on GPS modernization

On Friday of last week, the Office of Space Commercialization published a notice in the U.S Federal Register requesting public comments from within the United States and beyond on the U.S. government’s plan to phase out codeless and semi-codeless access to GPS by December 31, 2020.

This is an historic step. It will be the first time in history that GPS equipment will be rendered obsolete. Specifically, the units affected are high-precision, dual frequency GPS receivers that weren’t designed to use L2C or L5. For example, I have a set of dual-frequency RTK receivers that are about 12 years old – designed well before L2C and L5 specifications were finalized. They work great now, but would be affected by this change.

Granted, we’re talking about 2020, twelve years from now. But there are a great number of you (and me, to a certain extent) that subscribe to the “if it ain’t broke, don’t fix it” philosophy, and even if we did upgrade, we’d hang on to the old equipment as a back-up.

It’s important to recognize that the equipment will not stop working on December 31, 2020. The idea is that the DoD will no longer guarantee the availability of the Y-code on Block IIR-M, Block IIF and Block IIIA satellites that would used by codeless and semi-codeless receivers. Legacy Block II satellites would continue to broadcast Y-code until those satellites are decommissioned. But by 2020, not many legacy Block II satellites will still be operational. Legacy Block II satellites comprise 25 of the current 31 operational satellites today.

After I digest the Office of Space Commercialization’s notice a bit more and talk to a few people, I’ll publish my thoughts in this newsletter in the coming weeks.

What’s up with Galileo

Given some recent events, it’s about time to check in with you regarding Galileo, Europe’s attempt at creating a satellite navigation system similar to GPS. There’s also been some activity on the GLONASS front that is worth writing about too.

In my Directions 2007 article in the December 2006 issue of GPS World magazine, I wrote that Galileo has huge potential benefits for the survey/construction user. But I also wrote that the key new items to watch for would be significant delays. And the delays did come. The problem has been that Galileo is becoming known as the most talked about satellite navigation system that has never been … vaporware, if you will. The program has been belabored with delays and hiccups of both the political and financial sort for many years. One would surmise that after so many miscues that people would stop talking about it. The reason people don’t stop talking about it is that the benefits of Galileo to the satellite navigation user are so significant.

One of the major challenges that Galileo faces is funding. Galileo is to be the first global, civilian satellite navigation system. While GPS and Russia’s GLONASS are both funded by their respective defense departments, Galileo was going to be funded by a partnership between civilian government and commercial entities referred to as the Private Public Partnership (PPP). Exactly how much was private funding and how much was public (government) funding was the question that was a moving target for years.

Until May 2007, the PPP ball was in the hands of a consortium of private companies with the likes of Thales, Alcatel and Inmarsat among other members. Their job was to formulate a plan on how to operate Galileo; essentially, they were trying to figure out how to make it a viable commercial venture. They couldn’t come up with a plan, so in May 2007 Europe abandoned the PPP approach and conceded that the only way Galileo was going to get off the ground was via public funds, to the tune of €3.4 billion. In late 2007, the Galileo program was near death when the European Union (EU), comprising 27 countries, voted in November 2007 to keep Galileo alive, although funding was still an issue.

Just last month, the European Union transport ministers approved the Galileo Implementation Regulation, which allocates that €3.4 billion taken from the EU agriculture and administration budgets. With the money flowing and all 27 countries of the EU in favor, the path to launching Galileo seems as clear as it’s ever been. The next step is releasing contracts for the ground infrastructure and satellites. The European Parliament subsequently cleared the last bureaucratic hurdle later in the month. It approved legislative regulations that lay down security requirements for Galileo and the European Geostationary Satellite Navigation Service (EGNOS), both of which will be managed by the European Commission and the European Global Navigation Satellite System Supervisory Authority.

With the funding seemingly taken care of, however, the implementation schedule is less clear. The EU says the system will be ready by 2013. Folks, that’s only five years from now, not very long at all in the space systems business. They need to build the ground infrastructure, launch 30 satellites and write the software that needs to control and monitor all of the systems.

As far-fetched as the schedule may seem, Europe is dangling the Galileo carrot and I’m still chasing after it.

There is even a carrot dangling in orbit; the second Galileo satellite, GIOVE-B, lifted off late last month. Only 29 more to go — 28, if you count GIOVE-A, but it’s getting a bit long in the tooth.

I have a lot of patience because I’ve bet all along that Galileo was going to materialize. The reason is because of one key application that no other country is going to rely on a U.S. military system for: aviation navigation. It’s abundantly clear that the future of aviation navigation will be based on satellite navigation. How comfortable would the U.S. Federal Aviation Administration be with basing their entire navigation system on a foreign, military-run navigation system? They wouldn’t be and they wouldn’t do it. I think that’s about as comfortable as the EU would be with banking its aviation navigation future on GPS. GPS was a great proof-of-concept tool for them, but I don’t see how it’s a long-term solution for them. Galileo is.

We, as precision users of GNSS, would benefit greatly from Galileo. Frankly, if I had to choose between GPS modernization (L2C/L5/GPS III) and Galileo, I’d take Galileo. Even with 31 healthy GPS satellites broadcasting today, I still find myself losing productivity in the field because of the lack of satellite signals, and I hear similar complaints from others. If you’re trying to do elevation work, it’s even worse. Having ~30 GPS satellites and ~30 Galileo satellites available would mean your average number of satellites in view would be 20 plus. Your PDOP values would be ridiculously low throughout the day. Your redundancy and reliability would be ridiculously high. You wouldn’t have to choose a particular time of day to do your elevation work. Machine control wouldn’t be only usable in wide-open sky environments. These are days to dream about.

One could argue that Russia’s GLONASS system is closer to achieving this than Galileo. With GLONASS having 14 operational satellites, it’s a valid argument. But GPS and GLONASS were designed when the US and Russia were Cold War enemies. You can bet that United States and Russian scientists weren’t cooperating at that time. On the other hand, once the U.S. government decided to support Galileo (they didn’t initially), United States and European scientists worked closely together to ensure that GPS/Galileo receivers would work efficiently.

GLONASS/GPS receivers aren’t efficient by any stretch of the imagination. GPS is based on CDMA technology whereas GLONASS is based on FDMA technology. It’s kind of like designing a video cassette recorder (VCR) that accepts both VHS and Beta tapes in the same slot. You can design it, but there are consequences. One example in GPS/GLONASS receivers is that the receiver must use one GLONASS satellite to sync the two systems together. In real terms, if your GPS/GLONASS receiver is tracking three GLONASS satellites, only two are used. Power consumption is another issue.

These are some of the reasons you’ll never see a GLONASS/GPS receiver in the consumer market from Garmin, TomTom, Magellan, etc.

In response to pressure to be more compatible with GPS and Galileo, Russia announced earlier this year that they are near final approval in adding CDMA architecture to their GLONASS-K generation of satellites that are scheduled for launch in 2010. It’s a smart move on Russia’s part, as any system using anything other than CMDA in the next decade is going to be largely ignored by the manufacturers.

MSAS: SBAS in the Land of the Rising Sun

Quietly, the Japanese Civil Aviation Bureau (JCAB) has been developing that country’s MTSAT Satellite-Based Augmentation System (MSAS) over the years. MSAS is Japan’s satellite-based augmentation system (SBAS) that is designed to enhance GPS for aviation navigation. It’s similar and compatible with the United States’ Wide Area Augmentation System WAAS, as well as Europe’s European Geostationary Navigation Overlay System (EGNOS). It became operational in September 2007.

So, why am I writing about an aviation navigation system in Japan when this is a survey and construction column? Well, for the same reasons I’ve written about WAAS and EGNOS in the past. The use of SBAS by high-precision, non-aviation users is growing by leaps and bounds. I’m not talking about consumer GPS users. Autonomous GPS is so accurate these days that the average consumer doesn’t feel the benefit of SBAS vs. autonomous GPS. I’m talking about the professional users in mapping and surveying who require GPS equipment that will consistently deliver positioning at the meter-level and also at the centimeter-level. MSAS can help achieve both.

MSAS Coverage Area
MSAS was designed to be compatible with the United States WAAS program. Some of the same contractors, like Raytheon, for example, that helped develop WAAS were also involved in the development of MSAS. A GPS receiver designed to use WAAS, or EGNOS for that matter, can also be used to receive MSAS corrections.

Like WAAS and EGNOS, MSAS is a regional SBAS. It serves the region around Japan in support of aviation navigation. Also like WAAS and EGNOS, MSAS is a powerful tool for non-aviation users who require a highly accurate source of GPS corrections in applications like mapping and surveying.

If you are interested in using MSAS, the first question to answer is whether MSAS “covers” the area you are working in. Following is an MSAS coverage map:

It should be noted that this is the minimum coverage area. Some manufacturers have developed schemes to extrapolate the ionospheric grid when working outside of the published coverage area as well. Using this scheme, the grid map can be expanded by approximately 10 degrees in latitude and longitude.

For example, Thailand is slightly outside of the published MSAS coverage map. A typical GPS receiver designed for SBAS won’t be able to use MSAS corrections in Thailand. However, a GPS receiver designed to operate on the fringes of SBAS coverage areas may well be able to operate in areas like Thailand where there is no central SBAS for that country. Granted, this wouldn’t be useful for aviation users, but for ground users looking for meter-level accuracy, it may work just fine.

Essentially, the official, published coverage area is determined when a GPS receiver is in a position where it can see GPS satellites that are in view of at least two MSAS ground reference stations. This is the same for all SBAS. Following is a map of the MSAS ground infrastructure as presented by a representative from the Japan Aerospace Exploration Agency at the Institute of Navigation conference last September in Forth Worth, Texas. The full presentation can be viewed here.

Another factor in determining ability to use MSAS corrections is the visibility of the geostationary broadcasting satellites (GEOs). Like all SBAS, MSAS corrections are broadcast via geostationary satellites. To use MSAS, a GPS receiver must be able to receive corrections from one of those satellites. There are two satellites broadcasting MSAS corrections located at 140.0 degrees east longitude (PRN 129) and 145.0 degrees east longitude (PRN 137). Following is a map of the “footprint” that is covered by the two MSAS broadcasting satellites. Please not that just because a receiver located within the broadcasting satellite footprint does not mean it will be able to use MSAS corrections; it must also be within or on the fringe of the MSAS grid map discussed above.

Finally, not only does a receiver need to be within the MSAS broadcasting footprint of one of the two broadcasting satellites (GEOs), the signal from the GEOs is line-of-sight. This means that buildings, terrain, trees/vegetation, etc. can block the signal. Some manufacturers have developed various schemes to overcome this, but others have not, so just because a particular receiver is not able to use MSAS corrections, doesn’t mean that MSAS is unusable in that area.

MSAS Accuracy
While the JCAB doesn’t make available test bed results like the FAA does for WAAS, I’ve seen results of data collected using high-performance GPS receivers and MSAS as the correction source. The results are on the same level as WAAS, being well under a meter horizontally. Of course, there are a million caveats when discussing GPS accuracy, so I’ll leave it at that for now, but it does demonstrate the potential accuracy that non-aviation users could realize when using MSAS as a source of GPS corrections.

MSAS for Survey-grade GPS Receivers?
Up until this point in the article, the discussion has been for those interested in sub-meter or meter-level positioning for mapping.

Development efforts by some companies in the last couple of years have resulted in survey-grade GPS receivers with centimeter-level accuracy, benefiting from SBAS signals. One example is the Magellan PM3 RTK. It was introduced last year as one of the first L1-only real-time kinematic (RTK) systems. A key innovation in the PM3 RTK technology is its ability to use SBAS GEOs as a source of ranging measurements. Essentially, the two MSAS GEOs are treated as another constellation of satellites to augment GPS satellite measurements.

According to Magellan, the addition of SBAS makes a significant difference in resolving ambiguities for centimeter-level positioning. Following is a chart from a Magellan white paper.

SBAS for Non-aviation Users Continues to Strengthen
The utility of SBAS in the mapping/surveying/construction industries continues to grow. One indicator of a successful technology is that it spurs the development of other technologies around it. MSAS and SBAS in general have certainly done that.

Japan’s MSAS is the latest SBAS to become operational. Look for future reports on other SBAS, as India develops and introduces its system called GPS and Geo Augmented Navigation (GAGAN), which is referenced on the first graphic above.

RTK Crops Up in Precision Agriculture

Take a look at the major manufacturers of multi-frequency GNSS equipment and the markets they serve. Obviously, surveying is an important market; construction is a major one too. Maybe you’ve noticed that agriculture is also making its way up the food chain, so to speak. Trimble, Topcon, Leica/Novatel, Deere/Navcomm, and Hemisphere GPS are all pursuing the precision agricultural market with RTK-like precision.

The terms “precision agriculture” and “precision farming” have been around for a long time. There are conferences dedicated solely to sharing information on this topic, such as the 9th International Conference on Precision Agriculture. The classic precision ag market has been relatively unchanged for the past decade or so. Yes, in the past few years WAAS (Wide Area Augmentation System) has made a substantial impact with respect to a reliable and convenient source of corrections for one-meter accuracy using GPS, but all in all, one-meter accuracy is what most precision ag users have adapted to.

Stepping back, GPS/GNSS is only one component of the precision agriculture puzzle. Remote sensing (aerial photography/LIDAR), various sensors, and GIS (geographic information systems) software all play a key role in enabling people to record, analyze, and apply data used to make decisions that optimize the output of a particular agricultural area.

There are a few keys areas where GPS/GNSS is used in agriculture, though. These aren’t all-inclusive, but cover significant tasks where GPS has been very beneficial.

1. Field mapping: there have always been field maps of some sort, whether they were hand-sketched or derived from an aerial photo, but GPS has improved the precision substantially. Not only can one map the perimeter of the field, but also infrastructure such as roads, drain tile, outlets, wells, buildings, etc. The farmer doesn’t necessarily do this, but fertilizer distributors have become GPS-savvy and offer this service.
2. Yield mapping: as crops are harvested, a GPS receiver connected to a yield monitor sensor records a coordinate along with the yield data. This data is combined and analyzed to create a map of how well different areas of the field are producing.
3. Guidance: when spreading fertilizer or planting, equipment operators have traditionally used markers such as foam or other visual aids to mark where they’ve been to try and avoid overlap. The assistance of GPS and onboard guidance systems, such as a light bar, can further reduce overlap.

As I mentioned before, for many years precision ag users have settled for one-meter precision. Companies like Hemisphere GPS (formerly CSI Wireless) did very well designing single-frequency GPS receivers for the precision ag market. Hemisphere is also a leading designer of radio beacon (Coast Guard) receivers. Radio beacons, in addition to WAAS, are a free source of corrections for one-meter accuracy. Trimble was also an early supplier of precision ag GPS receivers and related equipment, typically offering single-frequency products like the AG-132.

While the real-time kinematic (RTK) technique has been around since the early 90s, it didn’t gain wide acceptance in the precision ag industry. The accuracy was great, down to approximately 2 cm at the time, but the equipment was clunky. The user had to set up a reference station near the field he was working on. The communication link was complicated, and some types needed Federal Communications Commission (FCC) licensing. Consequently, there were several potential points of failure. Lastly, the cost for a complete RTK system (base, rover, and radios) was high, upwards of $50,000. It just wasn’t cost-effective.

What is an RTK Network?

It’s an ambiguous term, because it means different things depending on the industry, but essentially the hardware setup is the same no matter which industry we are discussing. An RTK network is a series of dual-frequency reference stations spaced optimally within a region so as to provide RTK corrections to subscribers within that region. Following is an illustration of an RTK network for agriculture in the Ohio area.

All the reference stations are surveyed (more on that below) with respect to one another.

The network subscriber is assigned a primary reference station to use. RTK networks for agriculture are single-baseline solutions; the subscriber can only use one reference station at a time. There is no “network solution” per se, or redundancy like there is in RTK networks used in the surveying and construction industries. Therefore, when a single reference station “goes down,” the subscribers in that area are down also. There is software available from RTK network vendors that allows the administrator to monitor all reference stations via the Internet, but some networks don’t have that feature implemented. In that case the administrator hears about problems when subscribers have problems.

Another major difference between RTK networks for agriculture and RTK networks for surveying and construction is the communication method. The latter primarily use data plans on mobile phones to receive corrections. Either the mobile phone is linked via Bluetooth to the receiver or a cellular modem is built inside the receiver.

RTK networks for agriculture, on the other hand, primarily use spread spectrum radios (900 Mhz band) to transmit corrections to the receiver. The benefit of a spread spectrum radio is that they are free to use and don’t require a license from the FCC to operate. They are limited in their broadcast range, however, which is typically two to three miles. To solve this problem, radio repeaters are used to extend the distance. Depending on the topography, as many as four repeaters may need to be permanently mounted to effectively cover the broadcast range needed, based on the spacing of the reference stations. Even then, there may still be some areas that are not fully covered. In that case, temporary mobile repeaters may be used to provide coverage to that area.

The Wild, Wild West of RTK Networks

Bill Henning, real-time specialist with the National Geodetic Survey (NGS), said it best: the recent explosion of RTK networks is like the Wild, Wild West. They are proliferating so quickly that it’s hard to keep track of them. One of his tasks is to help develop guidelines for RTK network operators, and I think NGS is making inroads into the survey/construction industry with their initiative. People are looking for that sort of guidance with respect to RTK network setup, as well as monitoring for the networks once they become operational.

RTK networks for agriculture seem less structured than in other disciplines, though, and administrators rely more heavily on vendor recommendations. For example, some are based on the ITRF reference frame, while others are based on some version of NAD83. Some networks hire land surveyors to establish their reference station locations, while others do it themselves using NGS’s OPUS program or other methods. Very few, I think, realize the resources available from the NGS, such as the Cooperative CORS program.

Separate Industries, Separate RTK Networks

Even this early in the RTK network game, the duplicity of networks between agriculture and survey/construction is interesting. For example, an RTK network for agriculture can cover the same area as an RTK network for survey/construction. In the state of Georgia, there are several RTK networks for agriculture and several for survey/construction, some of which overlap. In fact, one would think that these folks (ag and survey/construction) would consolidate their efforts. The RTK network equipment is virtually the same. But alas, the manufacturers don’t want this. Why not? To answer that question, just employ the old adage: follow the money.

The fact is that a farmer isn’t going to pay the same RTK network subscription rate that a surveyor or construction company will. The numbers are vastly different. The typical subscription rate for access to an agricultural RTK Network is $1,300 to $1,500 per unit per year. Subscription rates for access to a survey/construction RTK network are as high as $4,500 per unit per year.

Some industry folks say that aggressive subscription pricing is the reason RTK networks in the agriculture market have expanded rapidly in the past few years. A farm is very hesitant to pay $4,500 annually when they can select a service like OmniSTAR and pay $1,500 annually.

Again, there are differences between the networks used in agriculture and those in survey/construction; most, if not all, are software-related. RTK networks for survey/construction offer a true networked solution, where several reference stations are used to compute a correction, whereas RTK networks for ag are single-baseline solutions, like users would normally set up as a base rover for their own use.

Others at the Party

Of course, OmniSTAR (HP/XP),Deere (Starfire), and Novariant (AutoFarm) offer a GPS-based solution in the precision ag industry. They are not pure-play RTK solutions like RTK networks are, although they do have RTK capability. True RTK networks are capable of constantly delivering ~2 cm accuracy day-in and day-out. These folks going after the precision ag market offer decimeter-level services primarily (1 decimeter being the equivalent of 10 cm), and then RTK solutions when needed.

It will be interesting to see how pure-play RTK players respond as RTK networks for agriculture continue to expand … which they most certainly will.

From A to B with PND

I covered this subject a while back, but I think it’s time to revisit it. Personal navigation devices (PNDs) are still selling like crazy. If you don’t have one, someone you know does. Tens of millions of these things are being sold per year.

If you don’t have one yet, you’ve got some options, because you can take it as a tax deduction. Perhaps a bit of “consult your accountant” verbiage should go here, but any time you need to drive from Point A to Point B for your job, I think you can take it as a deduction. Even if you do pay full price, it’s still a bargain.

First of all, you must be aware of the explosion in the number of consumer navigation units recently — you know, the Garmins, TomToms, Magellans, Mios, and Navigons of the world. If you go to Best Buy, Fry’s, Circuit City — even Radio Shack — you’ll see a bazillion of them on the shelf.

Disregarding the personal benefits of having one, I think they are one of the biggest bangs for your buck today, in terms of job efficiency. With labor being so expensive, I don’t see how a company can afford not to have one of these in each rig that’s headed to a job site. How many times have you (or one of your crew) gotten lost trying to find a job site, the local Home Depot, an ATM, or whatever? You aren’t just wasting your own time by being lost; it has a ripple effect.

I agree that PNDs aren’t for everyone. The solo surveyor working in his or her hometown and immediate surrounding towns probably knows the area better than Rand McNally. I’m thinking more along the lines of a contractor (be it a survey company or whatever) that has multiple people going in and out of a project. Maybe some employees are commuting directly from their homes, some are coming from the office, etc.

I think it’s hard to measure the stress, time spent, and other impacts of figuring out directions when working in an area that is not well known to the driver. Ever since I started carrying a little GPS navigator with me, I’ve virtually stopped using MapQuest or worrying about dealing with directions of any sort. Maybe you’re not like me, where you want to have all directions planned out in advance so you can stick to a tight schedule. To accomplish that, part of my preparation once included printing out all the directions and maps from MapQuest. I don’t bother with any of that now.

Even if you don’t use the directions feature, you’ve got a complete, nationwide electronic map at your fingertips. You can zoom out, zoom in, and pan around the screen. Following are some sample screens:

 

Which One Is Best?

Well, it depends. I hate that answer when I hear it, but it’s true. But this shouldn’t lead to “analysis paralysis,” where you can’t decide what to do so you don’t do anything. For me, there are four general features that are important to consider, no matter which additional bells and whistles you desire:

1. Display size. There is nothing worse than having to squint and try to focus on a micro-map when you are supposed to be driving. I like a large (relatively speaking), bright display. There are a couple of very common display sizes: 3.5-inch and 4.3-inch. Of course, the larger the display is, the larger the overall unit size is (and usually, the more expensive). I think the tradeoff is worth it for the larger screen size.
2. Ruggedness and reliability. It’s no better than a rock on your dashboard if it doesn’t work. I hate the flip-up antennas. Not many of the newer units have those any longer, but some of the older ones do. They are begging to get snapped off, unless you leave them permanently mounted on your dash. Also, some of the windshield mounts are pretty hokey, so be aware. In general, the various cable connections should appear solid.
3. Battery life. I guess this one depends on how you are going to use it. Personally, I like to take it from my dash and throw it in my laptop bag when I’m traveling by air. I dislike battery chargers in general (a necessary evil in this business), so I prefer a unit that will operate for at least five hours on one charge so I don’t have to cart the charger around with me.
4. Spoken street names. This is called “text-to-speech.” You can live without it, but it’s a nice feature. Instead of telling you “turn right in 500 feet,” it says “turn right in 500 feet on Main Street.” The lower-priced models typically don’t have this option.

There are many, many other bells and whistles you might like, such as real-time traffic data, Bluetooth for hands-free phone use, MP3 players, an FM interface to your vehicle sound system, etc., but those are more a matter of personal preference.

As coordinate-centric people, a lot of surveyors and mappers like to use State Plane. Very few navigation units support this sort of feature, although some support loading USGS topo maps in the background. I’m of the mindset that you really don’t want to try to do too many things with a PND, though. Call it a navigator and let it go at that. If you want a more coordinate-centric unit, then you’ll have to buy something other than a PND, like a Garmin GPSMAP 60CSx, DeLorme PN-20, or Magellan Triton.

I’ve put together a partial list of units with different features. The links are generally to the manufacturers’ websites, so don’t use the prices listed there as a reference.

3.5″ Display Units

TomTom ONE 3rd Edition (2-hr battery life, no text-to-speech, street-priced under $200).

Garmin Nuvi 200 (up to 5-hr battery life, no text-to-speech, street-priced under $200).

Garmin Nuvi 260 (up to 5-hr battery life, text-to-speech, street-priced under $300).

Magellan RoadMate 1200 (2-hr battery life, no text-to-speech, street-priced under $200).

Magellan CrossoverGPS (8-hr battery life, text-to-speech, IPX-4 waterproof rating, can load USGS topos, street-priced under $300).

Mio C220 (4-hr battery life, no text-to-speech, street-priced under $200).

Mio C310x (4.5-hr battery life, text-to-speech, street-priced under $250).

4.3″ Display Units

TomTom ONE XL (2-hr battery life, no text-to-speech, street-priced around $200).

TomTom GO 920 (up to 5-hr battery life, text-to-speech, street-priced under $500).

Garmin Nuvi 200W (up to 5-hr battery life, no text-to-speech, street-priced under $200).

Garmin Nuvi 880 (up to 4-hr battery life, text-to-speech, street-priced under $1,000).

Magellan Maestro 4200 (up to 4-hr battery life, text-to-speech, street-priced under $400).

Magellan Maestro 4250 (up to 4-hr battery life, text-to-speech, street-priced under $500).

Mio C320 (4-hr battery life, no text-to-speech, street-priced under $200).

Mio C720t (up to 3-hr battery life, text-to-speech, street-priced under $400).

There are many other navigator units on the shelves at the store. I’ve just listed ones from the top four market leaders.

You’ll notice I didn’t mention anything about the software interface. There are many opinions floating around about Brand X interface being better than Brand Y. After using a lot of different PNDs, I think the argument is about the same as Brand X total station/GPS vs. Brand Y total station/GPS. Most have very similar functionality, and their own idiosyncrasies, so it’s just a matter of getting used to it. One thing is for sure: the user interfaces are all different.

Don’t be stymied by analysis paralysis. A PND is the sort of tool (or toy) that once you get used to it, you can’t imagine working without it. Remember when folks fought against the electronic data collector, back when it was first introduced?

Catching Up

There has been a lot of activity on both the civilian and military sides of GPS/GNSS these past few weeks. Instead of a central theme to this newsletter, I’m going to comment on three points of interest: a DoD directive regarding position, navigation, and timing; PRN32; and some new product developments.

New Department of Defense Directive

On February 19, 2008, the Deputy Secretary of the U.S. Department of Defense (DoD) issued Directive #4650.05, which addresses, among other things, the “policy, procedures and responsibilities” for GPS. Although there will be many who will dissect and analyze the Directive for weeks to come, it’s clear that civilian influence on GPS continues to rise. You can read our Military and Government Editor Don Jewell’s initial comments here.

Of interest to the survey/construction/mapping community is the fact that the Department of Transportation is specifically mentioned as a key external agency (external to the DoD) to have a say in GPS activities. The Department of Homeland Security and NATO were the other two key external agencies named.

There is nothing earth-shattering about the directive, but it certainly sends a strong message that the federal government wants the civilian community — domestic and perhaps more so, international — to feel more comfortable about GPS, even though it’s still a U.S. military program.

PRN32

After a few months of waffling and discussion and announcements, PRN32 was finally set healthy. It’s been ready to go, but there has been concern about the effect that it would have on GPS receiver firmware. It was suspected that some GPS receivers wouldn’t be able to handle it, or would be adversely affected by it, because they may interpret PRN32 as PRN00.

This isn’t the first time that DoD has used PRN32. PRN32 was used temporarily in the early 90s until it was discovered that some GPS receivers interpreted it as PRN 00. It hasn’t been used again until now, some 15 years later.

Chances are that your receiver should be able to handle PRN32, given the event back in the early 90s and the DoD memo released more than a year ago. The satellite in question was set healthy on February 26, 2008. If your receiver is tracking but still not using PRN32, it may be worth a call to the dealer or manufacturer of your equipment to see if there is a firmware update available.

Depending on your location, PRN32 may help you. I was in the field in the western United States a couple of weeks ago, for example (before PRN32 was set healthy). I was only using five GPS satellites with an RTK receiver while down in a hole, and my receiver was tracking PRN32. It was in a perfect part of the sky that would’ve probably allowed me to get the tough shot I wanted, had it been set to healthy at that time, but no dice. I’m going back to the same site in a few weeks, and I’ll be watching for it. The RTK receiver I was using is more than 10 years old, so it will be interesting to see how it handles a healthy PRN32.

Product Announcements

Normally, I leave the new product announcements out of the editorial area, but three recent ones deserve particular attention. I mentioned two of them, from Javad GNSS and Magellan, in my December column of who to look out for in 2008. Both companies have come through in short order.

Javad GNSS. Early last month, Dr. Javad Ashjaee — former Trimble engineer and founder of Ashtech, Javad Positioning Systems (which was sold to Topcon in 2000), and Javad Navigation Systems — introduced the world to products developed by his new venture: Javad GNSS. In true Javad style, he’s pushing the envelope on both the technical side and the business side of the equation.

Of course, it’s expected that Javad’s new product line would account for every signal available, and probably every one that is planned. No disappointment there. His Triumph technology sports 216 channels to track everything from GPS L1/L2/L5 to Europe’s E1/E5 Galileo to GLONASS L1/L2, as well as all SBAS signals. That’s no big news, though, as all the other major manufacturers offer similar products.

What’s new and unique about Javad’s offering is the “RTK Umbrella.” The concept makes sense. The idea behind the RTK Umbrella is to increase the reliability of RTK positioning. A cluster of four antennas (on the rover) is used to compute sixteen baselines for every RTK measurement. Here is what the umbrella looks like.

After looking at it, you’re probably thinking the same thing I am: How am I going to cart that thing around all day? The short answer is, you won’t. But I can see an application where one could use the RTK Umbrella for setting control and performing other geodetic functions that require a higher degree of reliability and integrity. Then, you could toss it into the back of the truck and just use the single antenna for the production work.

It’s an interesting concept. I’ve got to give the guy credit for being creative.

Magellan. Magellan has been noticeably quiet in the high-end, survey-grade survey business for quite a while. The roots of their high-end business came from Ashtech, which they acquired many years ago. Yes, they have the Z-Max.Net that they announced a couple of years ago, but in a world where multi-constellation GPS and GLONASS receivers are the norm, it’s a me-too product at best. To give credit where credit is due, Magellan has continued to dominate the lower-end L1 survey-grade receiver market with its ProMark series of receivers and more recently, its ProMark 3 RTK product.

Now, as the company has been threatening to do (albeit under its breath), it has placed both feet squarely back in the high-end survey receiver business with the ProMark 500, a multi-constellation receiver that places Magellan in the same class as the best Trimble, Topcon, and Leica receivers. Granted, there is not a lot of information available on the ProMark 500, other than the video on its website. The real test will be when Magellan starts to ship the product, and dealers and users begin to run it in production mode.

My guess is that the technology will be pretty good. I think one of the biggest challenges will be to rebuild their surveying distributor network. With Topcon and Leica buying up distributors like candy in the past twelve months, the pickin’s are getting pretty slim.

Trimble. Remember when the Trimble ProXRS was the cream of the sub-meter mapping crop of receivers? It was a L1 C/A code workhorse of the past decade around the world. Then, it faded away when the ProXT/ProXH receivers were introduced. But neither of those really replaced the ProXRS.

Now, Trimble has upped the ante by introducing the ProXRT. The ProXRT offers users a range of accuracy depending on their needs, from sub-meter down to decimeter (10cm) accuracy. Perhaps the most significant feature is that the ProXRT is capable of using the Russian GLONASS satellites as well as GPS. The product announcement implies that GLONASS signals are used when GPS satellite availability is impaired. I have two comments about GLONASS on mapping-grade receivers.

1. Unless you are using your own GPS/GLONASS reference station, the GLONASS signals used on a mapping-grade handheld will be uncorrected (autonomous). Virtually no CORS receivers have GLONASS capability; neither NDGPS nor WAAS/EGNOS use GLONASS. So, there are no free public correction sources for GLONASS like those we are used to with GPS. However, many RTK networks are broadcasting both GPS and GLONASS corrections.

 

1. Autonomous GLONASS measurements offer much worse accuracy than autonomous GPS measurements, by a factor of five. This is because of the inferior clock and ephemeris data.

However, if used in the right circumstances, tracking a GLONASS satellite(s) can be the difference between getting a measurement or no measurement at all — even if the accuracy of the position takes a hit.

Another feature that the ProXRT brings back, which was curiously missing from the ProXT and ProXH, is OmniSTAR capability. The ProXRT is capable of using OmniSTAR’s VBS, XP, or HP service. This, of course, means that the ProXRT is a GPS L1/L2 receiver.

I’ll be attending the annual ACSM Conference on Thursday of this week. I’ll keep my eyes open for any other new developments. I’ll probably blog or otherwise comment on the conference somewhere on the GPS World website, as that is becoming our modus operandi when attending conferences. I like that format, and it brings you a bit closer to what’s happening if you are unable to attend the conference yourself.

With nearly 60 GPS engineers and scientists, the Jet Propulsion Lab (JPL) is one of the biggest GPS R&D centers in the world today. It operates as a division of the California Institute of Technology (Caltech), which manages the lab for the National Aeronautics and Space Administration (NASA).

Among other things, JPL operates the Global Differential GPS (GDGPS) system, which sells technical services and data and licenses software. The GDGPS system within JPL employs a vast, worldwide network of more than 100 L1/L2 GPS reference stations owned by itself and its partners.

Each reference station streams GPS measurements back to the GDGPS Operations Centers once per second. Data is then processed and analyzed in real time. Talk about redundancy — each GPS satellite is always observed by at least ten reference stations, and twenty-five is typical. Read more

It’s easy to get lost in JPL’s wide array of GPS product and service offerings, so I’ll try to stick with the part that’s closest to survey and construction.

Among other activities, JPL has people dedicated to monitoring and modeling the atmosphere — especially the ionosphere, which strongly impacts GPS measurements. They provide real-time, global maps of the Total Electron Content (TEC) used for L1 differential corrections around the world (think SBAS like WAAS and MSAS) and also for predicting ionospheric storms.

Dr. Michael Whitehead of Satloc, Inc. (now a division of Hemisphere GPS, Inc.), lead the first Wide-Area Differential GPS (WADGPS) commercial ventures to license JPL’s clock/orbit correctors and iono modeling services. This was back in the mid-90s, and Satloc’s target market was agriculture. Remember, this was before Selective Availability (SA) was turned off, so without a source of corrections, horizontal GPS accuracy without augmentation would routinely blow out to 100 meters. With its system, Satloc was able to deliver sub-meter L1 corrections to users via communications satellite.

“They (JPL) provided core technology. It worked great. The accuracy was there,” said Whitehead.

Whitehead said Satloc operated its own GPS reference network and internal software for generating corrections, but it also used JPL’s service to provide system redundancy. The Satloc system was set up to use corrections from either system (Satloc or JPL), and could automatically switch between the two systems.

The Satloc network was eventually sold to Fugro/OmniSTAR, another WADGPS service provider that integrated JPL data into its product offering. Hemisphere GPS/Satloc products now rely on WAAS (Wide Area Augmentation System) for their source of corrections. WAAS is built on core JPL technology, a predecessor of the GDGPS software. According to Whitehead, WAAS is very similar to the system that Satloc originally developed.

Fugro/OmniSTAR

Fugro/OmniSTAR operates its own GPS reference station network (over 100 worldwide, with 21 of those in North America) and has offered a WADGPS service in certain regions of the world dating back to the late 80s on a subscription basis. Until the late 90s, OmniSTAR/Fugro was a “one-trick pony,” offering a sub-meter “VBS” service for L1 GPS receivers. This is based on its worldwide network of GPS reference stations. Since then, the company has expanded its services in response to demand for greater accuracy and system redundancy.

Now, Fugro/OmniSTAR offers two additional levels of service: HP and XP. Both require the user to have a dual-frequency receiver (L1/L2). The upside is that the HP service provides +/-10cm horizontal accuracy using carrier phase (a sort of float solution). The HP service is based on Fugro/OmniSTAR’s proprietary GPS reference network and software. HP service is available in various regions throughout the world such as North America, parts of South America, Europe, the Middle East, Central Asia, and Australasia. The HP service is reference-station-dependent, meaning that the performance degrades as the user moves farther away from the nearest reference station (with a 300-mile limit).

Fugro/OmniSTAR’s other precise service, XP, is based on data licensed from JPL. The XP service offers horizontal accuracy of +/-15cm. The HP and XP services are similar in accuracy, but the JPL-based XP service offers global service rather than a regional service like HP. The difference is that while the HP service is baseline-dependent, the JPL-based XP service is not. That enhances Fugro/OmniSTAR’s coverage in remote locations where reference station coverage is sparse.

NavCom Technology

A leading-edge GPS design company licensing data from JPL is NavCom Technology, Inc., from Torrance, CA. Although the company name isn’t well known in the Survey/Construction industry, many of the engineers at NavCom are the same ones that designed the original Leica survey receivers while they were at Magnavox. There is some pretty high-end GPS design talent there — enough that John Deere Company bought NavCom, which now operates as a wholly owned subsidiary of Deere.

NavCom created and operates a GSBAS (Global Satellite-Based Augmentation System) called StarFire. While NavCom operates its own network of 20 worldwide GPS reference stations, it also has license agreements with JPL for reference station data and certain software. NavCom then refines and optimizes the data for NavCom receivers and distribution via the StarFire network. The result is that StarFire can deliver horizontal accuracies in the sub-10cm range after initialization.

NavCom has also created an interesting innovation it calls RTKExtend. Users of traditional RTK systems know that when the data link is interrupted, RTK operations are halted until the data link can be re-established. However, NavCom has combined traditional RTK with its StarFire network to assist RTK users. Users begin work using the traditional base/rover RTK configuration. If the data link is interrupted, the NavCom receiver automatically transitions to use the StarFire network, so the user can continue to operate at the centimeter level for up to 15 minutes.

Satloc, Fugro/OmniSTAR, and NavCom are just a few examples of commercial organizations that have successfully utilized JPL’s leading-edge GPS technology. There are also applications outside of the high-precision industry, such as mobile phone service providers licensing JPL to provide A-GPS data for E-911 anywhere in the world. With its unique global reach, JPL’s technology enables precision GPS applications even in regions of the world that lack infrastructure. It’s truly impressive to realize that decimeter-level positioning is available in most places in the world today; it’s just a matter of how to deliver the corrections. With the proliferation of wireless communications, even this problem will eventually be solved.

DOT Throws NDGPS a Life Preserver

It appears the US Department of Transportation has bought the Nationwide Differential GPS system (NDGPS) another year. The FY09 Presidential Budget Request was released earlier this week, and it contains a line item in the Research and Innovative Technology Administration (RITA) budget for NDGPS in the amount of $4.6M for operations and maintenance of the current system until October 2009. There is no budget item for the planned build-out of NDGPS. The budget request is subject to approval by Congress, but most likely this will go through.

The funding request is neither a thumbs-up nor a thumbs-down for NDGPS. The FY09 $4.6M budget request for NDGPS merely means that the DOT hasn’t figured out what to do with NDGPS yet, and the pain of having to fund a decommissioning program outweighs the $4.6M to keep it running for another year.

I think it’s the right decision. That may be intriguing to some of you who have followed my criticisms, but they have principally been directed at the stewards of NDGPS, not the program itself. RITA, regardless of how incompetent it has been at trying to understand this, needs more time to have a chance of comprehending how NDGPS is used.

Last year, RITA was funded $400,000 for a “needs assessment” of NDGPS. In other words, the administration is supposed to study and understand who is using NDGPS. Their primary attempt at this was opening a formal docket for accepting public comment last fall. You can read the Federal Register Notice here.

With an initial deadline for public response of October 1, 2007, the responses were very weak; about 30 comments were collected. The deadline was ignored by DOT, and more comments have been trickling in, with the last one posted January 28, 2008. As of February 4, 2008, there were 124 comments. However, because the explanation in the docket was written so poorly, some of the comments are not about NDGPS and obvious confusion exists between NDGPS, CORS, and OPUS. I read through every comment submitted.

After culling out the statements from by people who didn’t understand NDGPS or made meaningless comments, nearly one-third of the responses in favor of NDGPS were from National Park Service employees. Several submissions represented federal and state government users, from agencies such as the USDA, state DNRs, state DOTs, state geodetic surveys, and county and local governments. It’s hard to assign a number of users to those sorts of submissions, though. For example, in the USDA comment, it claims to have 7,000 GPS receivers in use nationwide, but you and I know that only a very small percentage use the NDGPS stations being considered for decommissioning. The USDA commenter also wrote that the loss of CORS “would have a severe impact on high-accuracy positioning.” Well, that’s not the case, so discounts the credibility of the agency’s support.

It’s sad that a pioneering GPS program such as NDGPS is being treated as it is today. Whether you support NDGPS or not, it has earned a fair shot — and it’s not getting it. That’s why I agree with the decision to fund it for another year while RITA pulls itself together. It will be very interesting to read the results of RITA’s $400,000 “needs assessment” report that was due to be completed January 30, 2008. If it’s anything like the joke of a report entitled “NDGPS Study” that was presented last fall at the CGSIC meeting in Ft. Worth, just go ahead and shoot me now.

Since the RITA docket failed to communicate to the public just what effect the loss of 26 NDGPS site would have for both NDGPS users and CORS/OPUS users, I’ll attempt to spell it out here, as clearly and concisely as possible.

What’s at Stake?

If the 26 NDGPS sites cease to operate, you will not be able to receive DGPS corrections from these sites.

Map of current DGPS and NDGPS sites:

Map of DGPS system minus the 26 NDGPS sites:

Following is a list of the 26 NDGPS sites on the chopping block:

• Hackleburg, AL (HAC)
• Flagstaff, AZ (FST)
• Bakersfield, CA (BKR)
• Chico, CA (CHO)
• Essex (Fenner), CA (CAE)
• Pueblo, CO (PUB)
• Macon, GA (MCN)
• Hagerstown, MD (HAG)
• Pine River, MN (PNR)
• Billings, MT (BIL)
• Polson, MT (PLS)
• Greensboro, NC (NCG)
• Medora, ND (MDR)
• Whitney, NE (WHN)
• Albuquerque, NM (ABQ)
• Austin, NV (AST)
• Hudson Falls, NY (HDF)
• Klamath Falls, OR (ORK)
• Seneca, OR (ORS)
• Hawk Run, PA (HRN)
• Clark, SD (CLK)
• Dandridge, TN (TND)
• Hartsville, TN (HTV)
• Summerfield, TX (SUM)
• Myton, UT (MYT)
• Spokane, WA (SPN)

What Alternatives Exist?

If you depend on one of the above sites for DGPS corrections (not CORS or OPUS but beacon corrections), what are your alternatives if the site is shut down?

1. The easiest choice is to switch to WAAS as a correction source. Most receivers are WAAS-enabled and, like NDGPS, it’s free. However, you’ll need to reconcile the horizontal datum difference between the two. NDGPS uses NAD 83(CORS96) and WAAS uses WGS-84(G1150). I’ve done this many times; it’s not difficult, but it needs to be done or you will introduce 1+ meter error.

Caveat emptor. Some GPS receivers handle WAAS better than others. Check for firmware updates from the manufacturer of your equipment. Also, some receivers don’t handle WAAS well when you are working under tree canopy or around buildings.

2. If you don’t require real-time corrections when you’re in the field, then you can choose to post-process your data. Post-processing software is fairly automated these days, but inconvenient nonetheless.

3. If you absolutely need submeter positioning in real time and your receiver isn’t capable of providing that via WAAS, there are several options.

OmniSTAR is a commercial provider of submeter and decimeter corrections. It may or may not work where you work, however, because it’s got a line-of-sight limitation. If you’ve got a GPS receiver with an OmniSTAR receiver already built in (e.g., Trimble ProXRS), then it would be relatively painless for you to try it. I seem to recall that OmniSTAR has a trial program of sorts.

RTK networks are popping up all over the country. Some are able to provide submeter corrections to mapping receivers via a mobile phone. Mobile phone data plans are relatively inexpensive, and you may even be able to rent one from a local GPS dealer when you need it. Most RTK networks charge a subscription or membership fee, but it doesn’t hurt to ask how they could accommodate you.

Believe it or not, it’s not that hard to take control by setting up your own portable base station and broadcast corrections. Yes, you need two GPS receivers (one to generate the corrections), and you need a way to get data from one receiver to the other (UHF radios, spread-spectrum radios, NTRIP, etc.), but it’s doable. It’s a little painful to put the system together, but once you’ve done it, you’re set for life. You don’t rely on anyone else.

Effects on CORS/OPUS Users

In shutting down the 26 NDGPS sites, one piece of collateral damage would be the loss of CORS and OPUS for post-processing using those sites. Is it an issue? For CORS and OPUS users, it’s not; for OPUS-RS users, it might be. I’ll explain.

First, let’s get definitions out of the way. When I write CORS, I’m referring to accessing RINEX data for L1 C/A post-processing. That’s you folks who use a Trimble Pathfinder, ProXR, etc., and post-processing the data to obtain meter-level accuracy. When I write OPUS and OPUS-RS, I’m referring to the National Geodetic Survey’s Online Positioning User Service, whereby you submit L1/L2 data and have their OPUS post-processing software reduce your data to centimeter-level accuracy and return corrected coordinates to you.

For CORS users, the loss of your favorite NDGPS site won’t affect you, except that you’ll have to use either the next-closest CORS site or a regional reference station from the US Forest Service or state/local government. There are a ton of them around, so that shouldn’t be a problem.

For OPUS users, the loss of the NDGPS sites won’t affect you. OPUS provides good results when using sites that are 500, 600, and even 700 kilometers away. If you go to http://www.ngs.noaa.gov/OPUS and click on Recent Solutions, you’ll see solutions from as far away as South America. I interviewed Dr. Dru Smith from the National Geodetic Survey in September 2006, and even back then, he said the days of needing to “use your favorite CORS” station are over. The OPUS software, he said, is designed such that an increased baseline distance is not an issue to be concerned with given the high density of CORS stations.

For OPUS-RS users in certain areas, the loss of the NDGPS sites may affect you. The difference between OPUS and OPUS-RS, to the user, is that OPUS occupations require a minimum of two hours, whereas OPUS-RS only requires a minimum of 15 minutes of occupation time. But a limitation of OPUS-RS is that the user position must be within 250 kilometers of three CORS; those three CORS stations must surround the user position (think good geometry). In certain regions, that will create a problem for users.

NGS has already conducted preliminary studies, determining that CORS coverage for OPUS-RS users in some regions of the country is deficient even with the NDGPS sites still active. Northern Maine, northern Minnesota, North and South Dakota, Iowa, Nebraska, Montana, Wyoming, Idaho, and northeastern Washington have been identified as deficient regions for OPUS-RS users, according to Dr. Richard Snay of NGS. Decommissioning the NDGPS sites in those areas would magnify the problem. On a positive note, Snay did say that NGS will soon be adding several CORS from the Minnesota Department of Transportation, so that will help OPUS-RS users in the region.

What’s the solution for the OPUS-RS users who would be affected if the DOT decommissions the 26 NDGPS sites? The easiest, and only, solution I’d recommend is to revert back to using the original OPUS program. This means planning for two-hour occupation times instead of 15 minutes. Secondly, I’d start lobbying your state DOT, county, and whoever else might be interested in setting up a cooperative CORS site in your area.

In summary, the impact of shutting down the 26 NDGPS sites has a minimal impact on CORS/OPUS/OPUS-RS users.

Back to the Budget

The FY09 NDGPS funding request is still only good enough to stop the bleeding for another year; it doesn’t solve the problem. When its study is completed, I seriously doubt RITA is going to find enough transportation applications to justify continuing to fund NDGPS under the DOT umbrella. Realistically, it’s going to be up to federal and state government users in the affected regions to pony up the funding. You can bet that no private entities are going to contribute significant funds, if any at all. They’ll find another solution before going down that road

Listed below are some of the major government supporters (or associations who represent government agencies) that submitted public comments in support of NDGPS. I think it will be up to them, and others, to come up with at least the Operations/Maintenance budget of approximately $5 million annually to sustain (not build out) the NDGPS as it is today.

• USDA (including US Forest Service)
• National Park Service
• Farm Service Agency
• Bureau of Land Management
• Maryland DNR
• Iowa DOT
• South Dakota Association of Local Government
• California DOT (CALTRANS)
• State of South Dakota
• Association of American Railroads
• North Dakota DOT
• North Carolina Geodetic Survey
• North Dakota Water Commission
• Washington DOT
• Idaho DOT
• National Association of State Departments of Agriculture
• Virginia DOT

3D Machine Control

One of the hotter topics in the construction industry these days is GPS/GNSS. If any of you attend the World of Concrete exhibition in Las Vegas, you’ll see many examples of how GNSS is being implemented in construction environments. The exhibition is expected to attract more than 1,700 exhibitors and 90,000 attendees this month. I’m sorry I’ll miss it this year, but if you do attend, you’ll find the usual GNSS (and related) suspects exhibiting: Topcon, various Trimble divisions, Leica, Sokkia, Seco Mfg, CST/Berger, Berntsen, etc.

Although the U.S. real estate construction market is clearly slowing (or shall I say dying?), the commercial construction market seems to be holding its own for the time being. The demand for construction automation equipment is still there, but I hear more about construction (and surveying) outfits wanting to rent GNSS equipment as opposed to buying it. This makes sense, as confidence in the economy is clearly waning.

Regardless of construction industry trends, there’s no lack of equipment automation opportunities (GNSS-wise) in the construction industry. Of course, precise positioning (topo surveys, construction staking, grade checking, establishing control, etc.) is one area of opportunity, but there’s also not-so-precise positioning, like navigating to job sites (a la “In 500 feet, turn left on Main Street”) and asset tracking (“Yes, Mr. Job Superintendent, we delivered that 2,500 feet of 2-inch PVC this morning at 9:10am; would you like to know exactly which staging area we delivered it to?”).

But perhaps no GNSS automation is causing such a stir as 3D machine control. Actually, it’s not 3D machine control itself, but the matter of who is technically and legally is able to provide the site data that’s used by the 3D machine control equipment.

I think the issue can be summed up in three statements:

1. Construction firms need 3D site data in order to use their 3D machine control equipment.

2. Engineering firms, those responsible for generating the plans, are hesitant to give up/generate the 3D site data because they’re concerned about exposure (errors and omissions).

3. Surveying firms, specifically those specializing in construction staking, aren’t too hot about the 3D machine control concept because it significantly reduces the need for construction staking.

I don’t think anyone knows how this is going to shake out yet, but I believe one thing is certain. The value proposition of 3D machine control for construction firms, when used on the right type of projects, is just too great for it to be ignored. As the old saying goes, just follow the money. As long as you believe that, then the responsibility of the 3D data preparation really doesn’t matter, because it’s going to happen. Granted, there might be a catfight before it’s all through, but it will be resolved.

I’ve sat through a couple of friendly discussions on this subject, must recently at the Trimble Dimensions conference, where folks — construction firms, engineers, and surveyors — had a chance to voice their opinions. I’ve also had the opportunity to work with a number of each of them. One recurring theme that stands out in my mind is the efficiency and resolve of construction companies. Well, maybe not efficiency at times, but certainly the resolve. They understand, as much as anyone, that time is money.

That’s a major reason they are so gung-ho on 3D machine control. The idea of not having to wait around for someone to pound or re-stake grade stakes or construction limits or whatever is like RTK: it’s addictive. In fact, contrary to what some may say, construction superintendents and operators are quite resourceful.

“Joe Engineering Co. said they weren’t going to provide the 3D site data?” Well in that case, Mr. Job Superintendent might just turn around and digitize the 100-foot-scale paper plans they’ve got. Two days later, they load up the 3D site data, and they are off and running.

I know, I know. That raises all kinds of issues. Copyright infringement, liability, etc. By the time you’re done listing the issues and debating them, the construction company has finished the project and moved on to the next job. Is that right — or even legal? Maybe, or maybe not, but that’s reality, at least for now.

The Solution?

To quote Chris Matthews from his book I just read, entitled Life’s A Campaign, “The people who show up get the chances.” I think it’s a mistake for engineers/surveyors to stonewall construction firms and attempt to withhold 3D site data. I think they’ve got to stay in the game and keep the data flowing.

Is it business as usual and just pass the DWG, Ma’am? No, of course not. There’s even an opportunity for generating revenue. Contractors are going to pay for 3D site data that has been certified for 3D machine control, if their other choices are using a dated, non-certified DWG file that’s passed through ten different e-mail threads, or trying to digitize paper site plans.

The game is changing. Are you going to show up?

GPS

On the GPS front, I’m going to paraphrase, plagiarize, and otherwise copy from my fellow newsletter editor Don Jewell, who writes the Military & Government PNT newsletter. He spent decades on the inside looking out (think Lt. Col. Jewell) and offers interesting perspectives.

First off, after a relatively quiet period since launching the first new modernized satellite, the Block IIR-M (offering the new L2C signal), in September 2005, there has been a flurry of activity and announced activity in the past 13 months.

First — Sept. 25, 2005. PRN 25/SVN 53 . Slot C4.
Second — Sept. 26, 2006. PRN 31/SVN 52. Slot A2.
Third — Nov. 19, 2006. PRN 12/SVN 58. Slot B4.
Fourth — Oct. 17, 2007. PRN 15/SVN 55. Slot F2.
Fifth — Dec. 20, 2007. PRN /SVN 37. Slot C1.

Remember, a total of eight IIR-M satellites were built; the GPS Wing says the remaining three will be launched in 2008. One of the remaining Block IIR-M satellites has been modified by Lockheed Martin, with the capability of broadcasting an L5 non-operational test signal. The L5 operational signal is planned for the next-generation GPS satellite, the Block II-F. The first II-F was due to launch in 2008, but this doesn’t seem likely…and it seems less urgent since the IIR-M modified to broadcast an L5 test signal will secure the signal spectrum. Securing a signal frequency, especially with the competing satellite systems from other countries is not a simple task — but we’ll save that discussion for another time.

So, from all public sources of information available, the current IIR-M launch schedule looks something like this:

Sixth — Mar. 13, 2008.
Seventh — June 2008.
Eighth — October 2008.

This is the flurry of activity I was referring to. Essentially, five launches within a twelve-month period.

And this is where I bring in some of Don’s valuable info:
“In the current constellation there are indeed 32 satellites, and normally that would be nearly the perfect constellation configuration, but a few of the older satellites and payloads are ‘single string’ in space parlance or on their last legs and require substantial care and feeding, including power management, by the very talented personnel/crews at the 50SW (Space Wing), 2SOPS (Space Operations Squadron) at Schriever AFB in Colorado, and the intrepid engineers at the GPS Wing at Los Angeles Air Force Base in California.

“Each GPS satellite is designed with an ‘A’ and a ‘B’ side that approaches 100% redundancy for critical systems. Several of the satellites were switched to the ‘B’ side years ago and have significantly outlived their design life, which differs with each series of satellites launched.

“Therefore, don’t be surprised that as we launch more and more GPS satellites (IIRM+s), the number of active satellites in the constellation stays the same. Since we have 32 satellites on orbit, remember that is almost the optimum number, we are in a replenishment mode, and attempting to maintain the constellation at the optimum number while still adding new capabilities, or modernization; a good thing for war fighters when we are involved in several hot conflicts/wars around the globe.

“Now, what about the nine possible failures of the IIA series GPS satellites? The satellites in question are all at or beyond their design life and have critical failures; they are being kept alive by heroic means that require exceptional amounts of time and money. If the worst should happen and all nine IIA birds fail, then we would be down to 23 satellites which is far from the optimum number — but remember we will be launching the rest of the IIRM satellites at the same time and that should put the number of on-orbit GPS satellites at about 29. Colonel Dave Madden says the goal is to stay as near the optimum number as possible but to certainly never go below 27 satellites if possible.”

So, I think the conclusion to be drawn here is that those of you who are experiencing “PDOP spikes” during the day that prevent you from being productive when using RTK will continue to experience those, even with the new GPS satellite launches. I mention RTK because that is the technology that relies most heavily on having a consistent number of observables (6+). Static post-processing users are affected, but to a lesser extent.

The bottom line, and I’ve made this point many times in the past, is that if you want more satellites observable, the solution in GLONASS. That subject transitions nicely into my next discussion.

GLONASS

Why is it that we always seem to hear about GLONASS satellite launches, but the number of operational GLONASS satellites never seems to increase significantly (and even decreases)? The answer is that legacy GLONASS satellites had a poor operating life span — well under four years. The good news is that the new GLONASS-M satellites they’ve been launching have a “guaranteed” operating life of seven years.

Since I touched on this subject last fall, six more GLONASS-M satellites have been launched: three on October 26, 2007, and another three on December 25, 2007 (Russia’s Christmas gift to GNSS users). Two of the October 26 satellites are operational, so there are four left in orbit and pending operational status. There are twelve operational GLONASS satellites as of December 29, 2007. This could increase to sixteen in the next couple of months as the four satellites already in orbit are made operational. That would be, by far, the most operational GLONASS satellites we’ve seen in recent years.

This is great news for GPS/GLONASS users. Actually, GPS/GLONASS users gain more marginal benefit from GLONASS satellites than from GPS satellites because GLONASS satellites are on different orbital planes than GPS, and therefore, offer a better opportunity to increase the quality of the satellite geometry (e.g., decrease your PDOP).

As in 2007, six GLONASS satellites are scheduled to launch in 2008. This is good, but we’ll probably see some legacy GLONASS satellites fail also. There are two that are past their fourth birthday, and three that just turned three years old last month. In the best-case scenario, we could see 22 operational GLONASS satellites a year from now. In the worst-case scenario, I can’t imagine having less than 14 or so available to us. Not bad considering we had as few as nine available during certain times in 2007.

Although it’s been a rough ride at times, I continue to be a passenger on the GLONASS bandwagon. You can keep up with the GLONASS constellation status by visiting

this Russian Space Agency website.

Topcon/Sokkia Merger

 

Switching gears a bit, we move on to December 10, 2007, when the Japanese Fair Trade Commission (JFTC) approved the Topcon/Sokkia merger. JFTC approval was needed because both companies are headquartered in Japan. The only constraint is that “non motor-driven total stations” sold in the Japanese market must be sold through a third party “in order to clear antitrust concerns posed by the JFTC,” according to the Topcon press release. You can view the entire press release here.

I think this is a boon for both Topcon and Sokkia. It gives Topcon another distribution channel to push its GNSS technology. It gives Sokkia access to a broader range of GNSS technology than they have with Point, Inc., their joint venture with NovAtel. Also, Leica recently bought NovAtel. Since Leica is a direct Sokkia competitor, it put Sokkia in a difficult position if the Topcon merger didn’t go through.

I don’t think this particular merger is a bad thing for the user community. My guess is that you’ll see some dual branding, like you did when Trimble acquired Spectra Precision. Even though it’s all Trimble technology, it markets the EPOCH GPS system under the Spectra name for the budget-minded user while still maintaining higher selling prices for its technology under the Trimble brand name. I could be wrong, but I bet Topcon/Sokkia does something like this.