Posted on 07/01/2011 11:40:09 AM PDT by ShadowAce
Wireless broadband firm LightSquared has admitted that its original plan would have knocked out most GPS sat-nav kit, but argues that its new plan will only leave 200,000 users lost.
Reporting on the results of several months of testing, involving 130 different GPS receivers, LightSquared admits that operating in the neighbouring band to GPS satellites will knock out a significant proportion of location-finding kit. But the company reckons its revised plan, announced last week, avoids interfering in all but the most-sensitive GPS kit: which LightSquared pegs at 200,000 devices around the USA.
Those are important devices, installed in aircraft to help facilitate instrument landings and in mining operations to guide the drill bit, but LightSquared argues that the only reason they're having problems is the lazy GPS industry which can't be bothered to play fair.
The results of the initial tests haven't been shared (we have asked for a copy, and the PDF summary contains details of the revised testing), but LightSquared claims all the tests show definitively that it isn't leaking transmissions into the frequencies in which GPS is supposed to operate (which start at 1559MHz). Instead the GPS receivers "have been deliberately or, sometimes, inadvertently, designed ... with the assumption that there would be no adjacent-band terrestrial transmissions".
GPS receivers straining to pick up the weak satellite signal are listening on too broad a band, according to LightSquared, which is why they have problems with when LightSquared transmits on its upper band despite there already being a significant buffer (the now-not-to-be-used band lies at 1545.2-1555.2 MHz).
So LightSquared said it will move to 1526-1536MHz for its launch, and claims that the independent testing in this band shows that smartphone and consumer GPS will all work and that only the 200,000 of so high-precision devices will have problems.
The GPS industry is, of course, having none of it. The Coalition to Save Our GPS sees no reason why they should be forced to change their designs, and contends that LightSquared's estimate of 5 cents per device for better filtering is entirely untested and no better than a guess. They also point out that LightSquared's new plan only delays the use of the upper band, and is based on (what they consider) a flawed assumption that the GPS industry will clean up its accuracy of reception.
Rather more hyperbolically, the Coalition also claims that that planes will fall from the sky and that allowing LightSquared to deploy will cost the US economy $96bn annually.
LightSquared responds that its network will contribute $120bn to that same economy, which would seem to make it a done deal if either figure had any semblance of justification behind it. LightSquared also points out that it has spent billions avoiding the GPS frequencies, while the GPS industry is built on the back of $18bn in government-funded satellite infrastructure.
There are also lots of arguments about who knew what, and when. LightSquared reckons the GPS crowd knew what was coming but chose to ignore it, while the GPS side say LightSquared was fully aware of the problem for years and just kept quiet about it in the hope no one would notice.
But historical questions are moot now, the important question is what happens next. The FCC has all the documents and the subject is now open to public debate before a decision is made. Save Our GPS is adamant that the FCC will have to decide between the two radio technologies, while LightSquared claims it can deal with the 200,000 problem devices and that the rest won't even notice.
Looks like it's going to be a long month for the FCC. ®
Part of the acronym "FCC" is "Federal".
If we're looking for a Federal agency to do The Right Thing, we're deluding ourselves.
You're listening on a frequency you're not supposed to. Your problem, you fix it.
Sounds to me like LightSpeed needs to make the adjustments. GPS was there first, and is used by critical systems. Which is not to say, if as LS claims, the GPS industry has been less discriminatory in it’s bandwidth tuning, that the GPS players don’t have work to do. But LS is the new player, and if there’s even a 1 in 10,000 chance that it might interfere with Nav/ILS systems (and I’m not talking Tom Tom), then, no go LS.
Just thinking .. the amazingly critical calculations for GPS navigation in aircraft; really only matters at airports. You need to drop that aircraft on a very specific spot and speed. Flying cross country, an error of a couple yards just doesn’t matter. It only matters where the rubber meets the runway.
Everywhere else - standard positional GPS should be ‘good enough’.
I've been thinking the exact same thing for a year.
Oh, well then. Nothing to see here, move along.
Wait until the lowest cost bidder in China wins the award to manufacture it all.
Probably some congress critters or important donors are invested init...just a guess....
LS also seems to be bleeding over quite a bit. Their problem, they should fix it.
So you buy some property next to an existing one. You want to build a fence on the property line, but your neighbor complains that you can't do that because he had planted his garden five feet into your property. You have someone demanding that you curtail your use of your property because he didn't properly contain his activities to his own property.
Lightsquared shouldn’t have gotten those frequencies in the first place. But since they got them, they need to be sure their use of them doesn’t interfere with existing devices. That definitely includes the “only” 200,000 aviation devices that are the most expensive and critical units.
I'd need some evidence to counter this statement from the report:
"The reason for this is not because LightSquared would be improperly transmitting in the GPS band. Rather it is because legacy GPS receivers do not adequately reject transmissions from base stations operating in the adjacent frequency band because the GPS receivers have been deliberately or, sometimes, inadvertently, designed or manufactured with the assumption that there would be no adjacent-band terrestrial transmissions.."
That’s LS’s position, but I’d need to see some evidence that my Garmin is indeed accepting interference from a different band.
I’ve heard that the owner of LS is a big Obama contributor.
Read the report and produce evidence to the contrary. It’s perfectly possible that LS is overstepping its band, but I haven’t seen anything to that effect yet.
I’ll take a look at it from both sides and see who’s right and who’s wrong. If you come up with anything please do let me know.
Thanks.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.