LightSquared: It’s Worse than You Think

May 18, 2011  - By

Tired of hearing about LightSquared? Think it’s a bunch of panicking journalists hungry for something to write about? Listen, it usually takes a lot to get the hairs standing up on the back of my neck. On the LightSquared issue, they are at full attention.


The GPS receivers that would likely be affected the most aren’t military, automobile, aviation, mobile phones, etc. The GPS receivers that would be affected the most are the ones you use, the high-precision GPS receiver!

This means any receiver designed to produce accuracies at meter-level or better (submeter, decimeter, centimeter receivers). This means surveying, engineering, construction, bridge/dam/structure/seismic monitoring, GIS, precision agriculture, mining, utilities/telecom, transportation, environmental, disaster management, and all sorts of machine control across a vast number of industries.

Do the Math

LightSquared is planning to construct 40,000 ground-based transmitters broadcasting 1,500W each across the U.S. These are targeted at metropolitan areas with high-density population. The will pop-up like mobile phone towers. What do you think a map looks like with 40,000 LightSquared transmitters overlaid on the current infrastructure of CORS (1,500+ GPS receivers in the U.S.) and RTK networks (100+ consisting of several thousands of receivers in the U.S.)?

Do you use OPUS? Do you use CORS? Do you use an RTK network? Do you use WAAS corrections? Do you use OmniSTAR? Do you use StarFire? Do you operate your own high-precision base station (real-time or post-processing)? I do not know one high-precision user who does not use one of the aforementioned technologies in their GPS operations. All of the above technologies are in jeopardy.

I’m going to keep this simple. You, the high-precision GPS user, are likely going to be considered collateral damage.

The military is going to be accommodated in the name of national security. The aviation industry is going to be accommodated in the name of safety-of-life. The auto navigation industry is going to be accommodated because they are high-profile. The high-precision user is going to be thrown under the bus because we are the most difficult to accommodate (technically) and don’t have a high profile nor are perceived as significant enough to accommodate.

In other words, the high-precision user will be told to “deal with it.”

What Does “Deal with It” Mean?

It’s not clear at this point, but without any hardware modification, your receiver performance will likely be degraded (weakened or lost signal) in metropolitan areas, and to a lesser extent in rural areas. That totally depends on where LightSquared decides to place its towers. Very soon, with the final Working Group report due to the FCC (June 15), we will see how serious the interference will be.

GPS receiver manufacturers would likely offer some sort of hardware upgrade, if possible. You can bet that they won’t support upgrading older hardware and it’s possible some newer hardware won’t be retrofittable, so the upgrade turns into a “trade-in” with a hefty price tag. But beware that a hardware upgrade doesn’t mean it will solve the problem, but rather minimize it.

In order to have a chance of not being forgotten or dismissed as collateral damage, you need to jump loudly and with resolution to raise awareness with your congressperson and the FCC about the importance of GPS to your operations. If you’re an international user, write the FCC.

You can view the list of submissions made to the FCC by clicking here. Deere & Co. as well as Fugro and many others provided very clear and concise comments.

The Coalition to Save Our GPS has posted guidance on its website as to how to submit your comments. They are:

Voice your concerns directly to Congressional Representatives

To voice your concerns about GPS interference, you can send letters, emails, faxes, call or visit your Congressional representatives’ office in person to explain how you use GPS as a local business and what the impacts of interference would be to the local economy.

Contact Your Local Senator

Ask your Senator to support and co-sign the attached letter from Senators Roberts (R-KS) and Nelson (D-NE): explain how you use GPS in your state and what impact interference or any compromise of the GPS service would have on you and the local economy.

United States Senate Letter from Pat Roberts (R-KS) and Ben Nelson (D-NE)

Find Your Local Senator

Write Your Representative

Find Your U.S. House of Representatives

Please include: “Coalition to Save Our GPS and FCC File No. SAT-MOD-20101118-00239” in your correspondence.

Send your comments directly to the Federal Communications Commission (FCC)

Email the FCC:

For your ready reference, below are the actions the Coalition is seeking from the FCC:

  1. The FCC must make clear, and the NTIA must ensure, that LightSquared’s license modification is contingent on the outcome of the mandated study unequivocally demonstrating that there is no interference to GPS. The study must be comprehensive, objective, and based on correct assumptions about existing GPS uses rather than theoretical possibilities. Given the substantial pre-existing investment in GPS systems and infrastructure, and the critical nature of GPS applications, the results of studies must conclusively demonstrate that there is no risk of interference. If there is conflicting evidence, doubts must be resolved against the LightSquared terrestrial system. The views of LightSquared, as an interested party, are entitled to no special weight in this process.
  2. The FCC should make clear that LightSquared and its investors are proceeding at their own risk in advance of the FCC’s assessment of the working group’s analysis. While this is the FCC’s established policy, the Commission’s International Bureau failed to make this explicit in its order.
  3. Resolution of interference has to be the obligation of LightSquared, not the extensive GPS user community of millions of citizens. LightSquared must bear the costs of preventing interference emanating from their devices, and if there is no way to prevent interference, it should not be permitted to operate. GPS users or providers should not have to bear any of the consequences of LightSquared’s actions.
  4. This is a matter of critical national interest. There must be a reasonable opportunity for public comment of at least 45 days on the report produced by the working group and further FCC actions on the LightSquared modification order should take place with the approval of a majority of the commissioners, not at the bureau level.


Lastly, following is the list of high-precision GPS receivers that the Working Group (consisting of US GPS Industry Council representatives and LightSquared representatives) have chosen to test:

Hemisphere R320 (with A52 antenna)
Hemisphere A320 (with Integral antenna)
Deere iTC (with Integral antenna)
Deere SF‐3000 (with Integral antenna)
Deere SF‐3050 (with Aero antenn
Trimble MS990
Trimble MS992
Trimble AgGPS 252
Trimble AgGPS 262
Trimble AgGPS 442
Trimble AgGPS EZguide 500
Trimble CFX 750
Trimble FMX
Trimble GeoExplorer 3000 series GeoXH
Trimble GeoExplorer 3000 series GeoXT
Trimble GeoExplorer 6000 series GeoXH
Trimble GeoExplorer 6000 series GeoXT
Trimble Juno SB
Trimble NetR9 (with Zephyr 1 antenna)
Trimble NetR9 (with Zephyr 2 antenna)
Trimble R8 GNSS (with Integral antenna)
Trimble 5800 (with Integral antenna)
Trimble NetR5 (with Zephyr 1 antenna)
Trimble NetR5 (with Zephyr 2 antenna)
Leica SR530 (with AT502 antenna)
Leica GX1200 Classic (with AX1202 antenna)
Leica GX1230GG (with AX1202GG antenna)
Leica GR10 (with AR10 antenna)
Leica Uno (with GS05 antenna)
Leica GS15 (with Intergral antenna)
Topcon HiPer Ga
Topcon HiPer II
Topcon GR‐3 (with Integral (5/8) antenna)
Topcon GR‐5 (with Integral (5/8) antenna)
Topcon MC‐R3 (with MC‐A3/cabled (5/8) antenna)
Topcon NET‐G3A (with CR‐G3/cabled (5/8) antenna)
Topcon TruPath/AGI‐3 (with Integral (special mount) antenna)
NovAtel PROPAK‐G2‐Plus (with GPS‐702/GPS‐701 antenna)
NovAtel FLEXG2‐STAR (with GPS‐701GGL/GPS‐701 antenna)
NovAtel FLEXPAK‐G2‐V1 (with GPS‐701GGL/GPS‐702 antenna)
NovAtel FLEXPAK‐G2‐V2 (with GPS‐702GGL/GPS‐702 antenna)
NovAtel PROPAK‐V3 (with GPS‐702GGL/GPS‐702 antenna)
NovAtel DL‐V3
NovAtel FLEXPAK6 (with GPS‐702GGL/GPS‐702 antenna)
Septentri PolaRx3e (with PolaNt GG antenna)
Septentrio AsteRx3 (with PolaNt G antenna)


Thanks, and see you next time.

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This article is tagged with , and posted in Opinions, Survey

About the Author:

Eric Gakstatter has been involved in the GPS/GNSS industry for more than 20 years. For 10 years, he held several product management positions in the GPS/GNSS industry, managing the development of several medium- and high-precision GNSS products along with associated data-collection and post-processing software. Since 2000, he's been a power user of GPS/GNSS technology as well as consulted with capital management companies; federal, state and local government agencies; and private companies on the application and/or development of GPS technology. Since 2006, he's been a contributor to GPS World magazine, serving as editor of the monthly Survey Scene newsletter until 2015, and as editor of Geospatial Solutions monthly newsletter for GPS World's sister site Geospatial Solutions, which focuses on GIS and geospatial technologies.

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