GPS in danger

Today’s POB eNews features a guest editorial from POB contributing editor Joseph Paiva on the conditional waiver granted to LightSquared by the FCC for its new broadband network. (Here’s a link to the story on POB’s website.) There is a lot of speculation that GPS signals may be in real danger. Has anyone else been following this story? Are you concerned about it?

POB and our sister publication, Site Prep, have been speaking with a number of individuals behind the scenes and will be sure to stay on top of it. Here's a link to a related story on Site Prep's website.

In my opinion if LightSquared signals interfere with GPS operations it should be considered an attack on the US Armed Forces and the military should respond accordingly. In otherwords, LightSquared is building a lot of practice targets.

Paul in PA

Me thinks this is a way for the "powers" that be to end the free L1 and L2 by creating frequency conflict.  Then they will (under subscription) pride new frequencies for us to use.

I certainly could have missed something, but to date I have not seen anything which indicated there was any evidence or any testing which indicated that these signals WILL or WOULD interfere with normal L1 GPS surveying operations. 

So is this all just a big over reaction?

Show me the citations.  My L1 receivers seem to be able to differentiate between 10-15 channels of existing signals, so why won't they be able to differentiate another a few Mhz off the channel? huh!!

Seems like POB could be dealing with some real issues instead of false issues. But I am willing to be educated, but it isn't happening here so far.

Give me the technical citations!!  i am willing to admit I am not an expert, but for darned sure a lot of commentary i have seen on this topic has not illutstrated any expertise that I can see. 

- jlw  

Jerry, here's some items for your perusal: 

http://freegeographytools.com/2011/how-the-fcc-plans-to-destroy-gps-a-simple-explanation
 

This is hardly a new issue.  It's been discussed in different forms for at least a decade.  Sally Frodge fought against the usurping of the GPS bands by the communications industry when she was at the federal DOT.  I attended one of her talks on the issue at an ION conference a very long time ago.  The GPS waveband has been a coveted thing, a target, for too long and there must be some encouragement coming from somewhere or it would have been handled by the Powers (DoD) long ago.

At one time, a few years ago, a statement was made that, "Voice has precedence over data". This still may have some bearing on the outcome of what is being proposed.

Total Stations and IMUs just went up a notch in my book.

In the other corner, however, couldn't our equipment use their signals too?  If the receiver can distinguish between original vs bouncing signals, I'd imagine that the offending broadcasters might actually improve precision in the cities where they are deployed. 

The receivers can't always tell the difference between original and bounced sig's, but the concern as I understand it and the concern many years back when I first heard about other interests encroaching on GPS's band is that GPS will be jammed/trampled.  It happens now and has for years at military installations--sometimes on purpose with their jammers and sometimes unintended with their communications frequencies.  It isn't just surveying that may be affected by this incursion into the GPS waves.  Most aircraft have switched to GPS as an important navigation tool.  I don't know what's up with this FCC decision, but it is not inconceivable that if they are mistaken it could have some negative consequences.

The sky is not falling!  GPS is quite possibly the most important invention in the last 50 years, and the trends regarding GPS have certainly been making it more accessible to Surveyors and the public alike.  GPS is not in danger.  Surveyors might be in danger though!

A new coalition has been formed to more-effectively share concerns with the FCC. Here's the basic information:

Coalition to Save Our GPS Formed

The sky may not be falling, but a lot of people are really concerned about the effects this new network will have on GPS. A white paper issued by the coalition states:

The usual FCC process is to conduct extensive testing followed by approvals. For LightSquared, the process was approve first, then test. The unusual waiver recently granted to LightSquared allows it to use its satellite spectrum for high-powered ground-based broadband transmissions if the company can demonstrate that harmful interference could be avoided.  

- Issues of interference should have been addressed before the waiver was granted.
- The waiver was granted just two months after it was requested. Even with such a short window, the U.S. GPS Industry Council (USGIC), the National Telecommunications and Information Administration (NTIA) – along with some federal departments, concerned state and local governments, public safety authorities, and GPS commercial users – all voiced strong objection to LightSquared’s plan to reposition the spectrum.
- The FCC’s conditional waiver puts LightSquared in the conflicting position of assessing whether or not its own system will interfere with GPS transmissions.

The full white paper and additional details will be posted soon. The coalition is also working on a new website, which will provide additional information as it becomes available.