LightSquared Spars with U.S. Gov't Over New GPS Testing

CommanderFrank

CommanderFrank

Cat Can't Scratch It
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In a leaked document of the latest round of testing of the proposed LightSquared 4G LTE service, the government concluded LightSquared signals are disruptive to 75% of the GPS devices used in the testing. The full report will be presented to the Commerce Department on December 14th.

"LightSquared signals caused harmful interference to majority of GPS receivers tested," reads the draft. "No additional testing is required to confirm harmful interference exists."
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This whole thing is a joke. Lightsquared knew exactly what they were getting into when they bid for this. It doesn't take an RF engineer (which I am sure they had on staff anyway) to figure out this was going to cause significant problems in the GPS band.

Filters are expensive and imperfect in both analog and digital form.
 
Not included in your summary is that the leaked results were testing done at FIFTEEN times the power Lightsquared has said they will transmit at.

In other words - it's like coming to the conclusion that your computer's power supply is destroyed if electricity flows to it because you sent 1,800 volts at your 120 volt power supply. That doesn't mean your PSU can't handle electricity, that just means you sent 15 times the voltage you should have to it!
 
chris719 said:
This whole thing is a joke. Lightsquared knew exactly what they were getting into when they bid for this. It doesn't take an RF engineer (which I am sure they had on staff anyway) to figure out this was going to cause significant problems in the GPS band.

Filters are expensive and imperfect in both analog and digital form.
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If by 'filters are expensive' you mean the filters that can handle Lightsquared operating in their own band cost $6 and GPS makers wanted to save a buck (literally A BUCK) and not use that quality of filter (why would they when they can whine about it and try to prevent Lightsquared from using the frequency it owns right?)
 
Ualdayan said:
Not included in your summary is that the leaked results were testing done at FIFTEEN times the power Lightsquared has said they will transmit at.

In other words - it's like coming to the conclusion that your computer's power supply is destroyed if electricity flows to it because you sent 1,800 volts at your 120 volt power supply. That doesn't mean your PSU can't handle electricity, that just means you sent 15 times the voltage you should have to it!
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Lobbyists have a way of getting certain tests favored in their advantage. IE: All the telecom industries who don't want another competitor.

I'd be interested in seeing the exact same tests done at only 2, 3, or 4 x the "proposed" power. 15 times is quite an awful lot. I understand going over a little bit, but damn.
 
Ualdayan said:
If by 'filters are expensive' you mean the filters that can handle Lightsquared operating in their own band cost $6 and GPS makers wanted to save a buck (literally A BUCK) and not use that quality of filter (why would they when they can whine about it and try to prevent Lightsquared from using the frequency it owns right?)
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Wouldn't be the first time a company didn't do something to save a few bucks on manufacturing... hell I remember the cluster fuck of cars that only had one side mirror in the 80s because they figured most people only needed one... *yeah until you try to parallel park*

That said, can't Lightsquare tighten their transmission spectrum up a bit? Or are they literally operating on a frequency 1 hertz wide or something?
 
sfsuphysics said:
That said, can't Lightsquare tighten their transmission spectrum up a bit? Or are they literally operating on a frequency 1 hertz wide or something?
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They're operating in spectrum that is reserved for satellite broadcasting. At the moment, their signal would be considered illegal.
 
SLee said:
They're operating in spectrum that is reserved for satellite broadcasting. At the moment, their signal would be considered illegal.
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So the government willingly sold them a spectrum that they could not use?
 
Ualdayan said:
If by 'filters are expensive' you mean the filters that can handle Lightsquared operating in their own band cost $6 and GPS makers wanted to save a buck (literally A BUCK) and not use that quality of filter (why would they when they can whine about it and try to prevent Lightsquared from using the frequency it owns right?)
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There's no evidence that filters only cost a buck, certainly the initial ones are much more expensive and yet to be tested.

Of course, GPS manufacturers did not include such filters because

a) Even at reduced power levels of 1.5KW, LightSquared's signal is still upwards of a billion times stronger than the GPS signal at the surface of the Earth
b) Such a signal in the satellite spectrum is illegal under current laws
c) The FCC had explicitly forbidden such networks from ever been created in the past
 
sfsuphysics said:
So the government willingly sold them a spectrum that they could not use?
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The original business of LightSquared is for satellite data and communication. Ironically, one of their markets is to broadcast GPS augmentation signals using their satellites. However, the satellite business is a tough business so they managed to convince the FCC to allow them to build a powerful terrestrial LTE network in a very unusual process (announcement made just before Thanksgiving 2010, 1 week comment period).

However, protest from the Department of Defense and other Federal agencies forced the FCC to require testing before the network could be enabled. LightSquared failed the first round of tests badly, so they've come up with a new (but temporary) configuration that was supposed to cause less interference. This is first set of tests for this configuration. If you want more information, this site is a good place to start:

http://www.pnt.gov/interference/lightsquared/
 
Considering how GPS driven we are as a society(not to mention all of the military applications), I have been very concerned with this since the very first day we heard of it. If something is proven to cause harmful interference to potentially so many devices out there, it doesn't make sense why they are going ahead with this.
 
What I want to know is how come the towers were even able to transmit at 15 times their proposed signal strength? It's not like components could be run at those levels if they weren't designed for it. Since they obviously were, why?
 
chris719 said:
This whole thing is a joke. Lightsquared knew exactly what they were getting into when they bid for this. It doesn't take an RF engineer (which I am sure they had on staff anyway) to figure out this was going to cause significant problems in the GPS band.

Filters are expensive and imperfect in both analog and digital form.
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Well then you shouldn't be able to sell something that you know is unusable. Its simply fraud on the government's part for doing so.
 
bacon said:
Well then you shouldn't be able to sell something that you know is unusable. Its simply fraud on the government's part for doing so.
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LightSquared has a license for satellite broadcast and an ancillary terrestrial component allowing a backup network of terrestrial stations for use in areas of poor satellite coverage but is explicitly forbidden from building a purely terrestrial network. There is nothing stopping LightSquared from using its current spectrum in the way that it was licensed for.

It's not fraud if the government sells you land zoned for residential but stops you from building a factory on it.
 
Ualdayan said:
If by 'filters are expensive' you mean the filters that can handle Lightsquared operating in their own band cost $6 and GPS makers wanted to save a buck (literally A BUCK) and not use that quality of filter (why would they when they can whine about it and try to prevent Lightsquared from using the frequency it owns right?)
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Sorry, if you had any clue how RF works you would know that there is no such perfect solution for every product.

Lightsquared's signal is so strong compared to GPS that intermodulation products from their band just being nearby will degrade GPS reception, filter or not, in most devices.

Their own data considered a 6 dB loss in carrier-to-noise ratio acceptable, which is not really. That -6 dB reduces the signal to 1/4th of it's original power.

When these GPS devices were built, the manufacturers were under the belief this spectrum would be used for much lower power transmission. All consumer electronics are made as cheaply as possible and everyone knows this.

This is some kind of money grab... has to be. Why didn't anyone else with more money buy this spectrum for this purpose? Because they aren't fucking stupid.
 
chris719 said:
Sorry, if you had any clue how RF works you would know that there is no such perfect solution for every product.

Lightsquared's signal is so strong compared to GPS that intermodulation products from their band just being nearby will degrade GPS reception, filter or not, in most devices.

Their own data considered a 6 dB loss in carrier-to-noise ratio acceptable, which is not really. That -6 dB reduces the signal to 1/4th of it's original power.

When these GPS devices were built, the manufacturers were under the belief this spectrum would be used for much lower power transmission. All consumer electronics are made as cheaply as possible and everyone knows this.

This is some kind of money grab... has to be. Why didn't anyone else with more money buy this spectrum for this purpose? Because they aren't fucking stupid.
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Wait...so you acknowledge GPS makers cut corners that the original GPS specification says they shouldn't, you excuse that with 'all electronics are made as cheaply as possible' then lay the blame at Lightsquared for trying to use spectrum they bought in a way the FCC told them they could?

You can say 'Well you don't know anything about RF', but you know who does? GPS makers. GPS makers who didn't cut corners to save a buck a filter. Javad GNSS for example. People love to throw around terms like 'it's a billion to one, you know how hard that is to filter!' to try to make others think it's some impossible task. If I told somebody 'That CPU can do trillions of mathematical operations per second' that would sound pretty impressive too, doesn't mean it's impossible or even rare nowadays. GPS component manufacturers like Partron and PCTEL have already come out and said 'We charge $6 for a filter that can handle Lightsquared's frequency/power.'
 
Ualdayan said:
Wait...so you acknowledge GPS makers cut corners that the original GPS specification says they shouldn't, you excuse that with 'all electronics are made as cheaply as possible' then lay the blame at Lightsquared for trying to use spectrum they bought in a way the FCC told them they could?

You can say 'Well you don't know anything about RF', but you know who does? GPS makers. GPS makers who didn't cut corners to save a buck a filter. Javad GNSS for example. People love to throw around terms like 'it's a billion to one, you know how hard that is to filter!' to try to make others think it's some impossible task. If I told somebody 'That CPU can do trillions of mathematical operations per second' that would sound pretty impressive too, doesn't mean it's impossible or even rare nowadays. GPS component manufacturers like Partron and PCTEL have already come out and said 'We charge $6 for a filter that can handle Lightsquared's frequency/power.'
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Are you dense? These GPS recievers were developed BEFORE LightScam.. er I mean LightSquared came up with their stupid plans. How the hell are they supposed to predict there would be very high power transmission on a neighboring spectrum designated not for terrestrial use.

If LS was going to destroy FM radio reception, who's problem would it be?
 
Ualdayan said:
Wait...so you acknowledge GPS makers cut corners that the original GPS specification says they shouldn't, you excuse that with 'all electronics are made as cheaply as possible' then lay the blame at Lightsquared for trying to use spectrum they bought in a way the FCC told them they could?
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There is no GPS specification that says there will be 1500W terrestrial transmissions anywhere from 4 to 24 MHz away from the lower edge of the GPS L1 band, nor any FCC authorization allowing it.

The single key problem is that LightSquared is using their spectrum in a way that the FCC has in the past never allowed.
 
People are mostly thinking of their car or phone GPS units. The accuracy of those types of units is measured in meters. It's really the high precision (1 or 2 centimeter) units, that cost thousands of dollars to buy, that will be rendered nearly useless by Lightsquared.

Everyone knows the military uses for GPS, but they should also think about construction companies that have GPS built right into their dirt moving machines. Think about land surveyors locating property corners or other improvements. Think about city infrastructure locations (most larger cities have GIS databases that they use for emergency services like ambulances and police, planning and maintenance of utilities, etc)... The list is long.

While the high precision GPS users are a minority of the population in terms of total numbers of units, the cost of losing that high accuracy ability would be high.
 
VRMan said:
Not me, I stream music through my cell phone into my car radio. AM/FM should be retired like a 50 year old whore.
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AM should maybe be retired for 911 services... FM is still AWESOME for many people, cmon now man, not everyone is 1st world. FM is dying slowly, which is a shame (no more alt rock station in my popular city, what a shame)


And 50 yr old whores are still useful, and can provide cheaper services, no?
 
Old_Way said:
People are mostly thinking of their car or phone GPS units. The accuracy of those types of units is measured in meters. It's really the high precision (1 or 2 centimeter) units, that cost thousands of dollars to buy, that will be rendered nearly useless by Lightsquared.

Everyone knows the military uses for GPS, but they should also think about construction companies that have GPS built right into their dirt moving machines. Think about land surveyors locating property corners or other improvements. Think about city infrastructure locations (most larger cities have GIS databases that they use for emergency services like ambulances and police, planning and maintenance of utilities, etc)... The list is long.

While the high precision GPS users are a minority of the population in terms of total numbers of units, the cost of losing that high accuracy ability would be high.
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Agriculture is another big user of GPS now; tractors can be driven by them to create incredibly precise plots.
 
Let's not forget that Lightsquared is backed by Harbinger Capital. These guys are being investigated by the SEC and could be charged with violating securities laws. When you see one cockroach, you know there are many more hidden...
 
There has to be another story behind this.....why would anyone spend this kind of money only to get to this point? I bet they pissed off some either very rich or very powerful people. I also wonder why they would use soooo much power for testing this stuff? You'd expect some interference in that case wouldn't ya? Someone said earlier its a money grab....i would also suggest power grab as well.

Also, if elements in the government could make an excuse that this is a "national security" issue would you put it past anyone in washington to stoop to some seedy means to get what they want?

There has to be something else behind this....not just in how this story is worded but, it just dosent add up....would be nice to get the real story behind much of what is fed to us on the TV/media.

For example, I get 8 korean channels from South korea. More than just a couple times we would hear a story here in the USA, and then the same story pops up in korea but, its description of the story or problem is totally different from what we hear. Often after comparing the two you can usually tell which one is closer to what actually happend. As they say, you cant believe everything you read in the paper.
 
Magnus said:
What I want to know is how come the towers were even able to transmit at 15 times their proposed signal strength? It's not like components could be run at those levels if they weren't designed for it. Since they obviously were, why?
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LightSquared has been changing certain parameters of its network ever since the devastating test results released in June. Based on my understanding, the government is testing at 1500W, the initial stated operational power level of LS transmitters. However, LS had changed the power levels in September such that initially, the minimum power levels of some transmitters will be at 100W. However, they will be increasing it over time, until it finally reaches the original 1500W levels.
 
Ualdayan said:
..then lay the blame at Lightsquared for trying to use spectrum they bought in a way the FCC told them they could?'
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Lightsquare was given a licence for testing purposes to demonste proof of concept. The FCC didn't want to issue any sort of licence but only did so after political pressure.

Chirs719s comments are spot on.

If LS would have talked to any RF engineer or spectrum manager they would have known that the unencrypted course acquisition mode for GPS is very, very sensitive to electromagnetic interference (EMI). They would have also learned that not only does the FCC protect this band but the NTSB considers this band to be non-negotiable for EMI. The band is also protected by the ITU around the world.
 
puttersonsale said:
There has to be another story behind this.....why would anyone spend this kind of money only to get to this point?
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Mainly it's because of the possibility of even more money combined with staggering engineering incompetence.

LightSquared has spent around $2 billion so far. However, if they were successful in getting FCC authorization to build a terrestrial network, then the value of their spectrum jumps to around $12 billion (based on recent spectrum auctions).

However, apparently either they didn't have a single technical expert in their company or were so blinded by greed they forgot to consider GPS.
 
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