Watchdog Reveals LightSquared’s Fall from Favor in Washington

 - January 5, 2012, 12:40 AM

One of the supreme ironies of the ongoing LightSquared saga is that the company’s efforts to promote its nationwide email initiative are not helped when emails about its own activities, written by U.S. government bureaucrats, become public under Freedom of Information legislation.

Recently, the Citizens for Responsibility and Ethics in Washington obtained more than 13,000 documents relating to LightSquared from the White House Office of Science and Technology Policy (OSTP), a critical Washington, D.C., “gatekeeper.” Going through the whole information dump could take weeks, but so far telecoms industry technology expert consultant Tim Farrar has pinpointed items that show clearly how official attitudes toward LightSquared have changed over time. In July 2010, the OSTP’s chief of staff felt LightSquared’s activity was “exciting,” and in September 2010 he kept “hearing great things” about the company.

Clouds Gather for LightSquared

But by early 2011, LightSquared’s counsel was asking “if there’s anything NTIA [the National Telecommunications and Information Administration] can do with the press on background to calm the waters” because “Press reports…are leading to big problems with investors–present and potential–customers, Sprint, et al.” By June 2011, following the report of severe GPS interference during government tests, plus increasing Congressional demands for top-level government documents, showed that “things were heating up.”

In August, the previously compliant FCC put out a self-protecting assertion that it would not allow LightSquared to operate until the interference question was resolved, which translated into “headwinds” for LightSquared. Also in August, after LightSquared had suggested discussing with the NTIA how to move things forward, the NTIA Administrator responded in an email headed “LightSquared is in Wonderland.” And by September, things started to become decidedly frosty, with a senior government official telling a representative from Harbinger Partners, LightSquared’s owners, “I must ask that you stop communicating with me regarding the LightSquared matter.”

Normally, that response would chill the average executive, but not Harbinger’s president Philip Falcone. With remarkable prescience, and later the envy of the financial community, he saw an opportunity in the meltdown of the sub-prime mortgage market to become a multibillionaire. His current investment in LightSquared is reported to be close to $3 billion, of which around $ 2billion was used to buy the assets–including two FCC-allocated frequencies in the radio spectrum’s L-Band–of a failing satellite Internet provider. And here again, Falcone’s approach sidestepped conventional wisdom.

Market research showed that government agencies could permit those weak satellite signals to be augmented by strategically located ground transmitters, to fill in the areas of poor reception. In fact, the FCC had already approved the technique for LightSquared’s predecessor, but it was never put into practice. So what could make more sense than following the FCC’s approval? Unfortunately, the agency wasn’t ready for Falcone. While the FCC saw the value of the augmentation concept in poor reception areas, it never thought to impose an upper limit on just how many ground stations would be needed, and how powerful they should be. After all, from reasonable–but blinkered–engineering considerations, it shouldn’t require that many, and they wouldn’t need to be powerful. Wrong again.

By the time that LightSquared gained FCC approval–reportedly fast tracked due to some adroit political maneuvering, it was getting ready to launch the nationwide network of 40,000 powerful ground stations, along with a plan to sell commercial advertising to all comers on a wholesale basis, neatly sidestepping another minor FCC impediment that the actual owner of the system isn’t allowed to advertise directly on line. The other unexplained oddity that the FCC approval was signed off by the chief of the agency’s International Office, even though LightSquared has no immediate plans to operate outside the U.S. Reportedly, the views of some FCC engineering and spectrum people who would normally be involved in such things was not requested.

The only problem that LightSquared has had to face is FCC’s stipulation that its ground station transmissions must not interfere with GPS, and it is now starting to look like the plan’s Achilles Heel. Somehow, the company’s original analysis of potential show stoppers utterly failed to recognise the likelihood of serious interference with GPS and the size, breadth and importance of the user community. Unquestionably, the seemingly disastrous results of tests performed in March by the DOD, FAA and other expert authorities, using a wide range of GPS receivers, came as a nasty shock to LightSquared and to some of its investors, and also had repercussions in political circles.

The March tests were conducted on the upper of LightSquared’s two frequencies that was closest to the GPS frequency. Tests in November of cellphones and general receivers against the lower frequency showed minimal impact on cellphones but interference with general-user receivers. LightSquared’s response has been to offer free filtering modifications to a relatively small number of specialized government survey receivers, but no other government units. LightSquared has no plans to help civilian users. It is, LightSquared states, the GPS manufacturers’ responsibility.

Yet despite these apparent setbacks, LightSquared still has a strong reserve of chutzpah, along with an obvious fondness for horse trading. Since its upper frequency is unlikely to be approved for use in the foreseeable future, it has proposed to the FCC that it would be willing to relinquish its claim to it, providing that in exchange it be granted government fast tracking of its use of the lower frequency. Conveniently, this ignores the fact that even that frequency has created interference and is a particular problem for the precision survey and similar industries that have major GPS equipment investments. As well, LightSquared has made the intriguing suggestion that instead of having tests performed by government bodies the only true evaluation of things such as claims of interference can be made by experts in the user community. Good luck with that, on pointing out the errors of their ways to the FAA.

What happens next is a good question, and perhaps more pressing upon LightSquared, which may be taking a much larger toll of Falcone’s fortune than he originally anticipated.

Comments

Reading Lightsquared press releases incenses me. I appreciate an author that goes beyond just paraphrasing what Lightsquared says, and reports what is really going on. Thank you.

LightSquared, or any competitor using near frequency strong terrestrial transmission, will produce an off-band signal that will be received by the GPS receiver because of the bandwidth of the GPS receiver "patch" antenna. This is called "quality factor" or "Q" and is a measure of center frequency divided by 3db bandwidth. Unfortunately, GPS uses a high frequency, and Q diminishes with frequency (why radios and TVs all use a lower frequency IF stage, to get better transmitter station selectivity, and do not count on the antenna or RF stage for much help there).

GPS receivers can use a DSP computer to, and we will use the analogy of a noise canceling headset, make an interference signal "anti-noise" to add into the desired signal with noise, to remove the noise from the desired signal. Unfortunately, the signal must also be heard in the signal plus noise coming from the antenna to the DSP computer input.

Design assumption: the filter between the patch antenna and the first LNA RF amplifier inside the GPS antenna must reduce the interference signal amplitude down to equal to or lesser than the desired GPS signal before the DSP computer can be effective at eliminating the noise.

If you have zero loss at the GPS bandpass, how much LightSquared signal attenuation do you need over the entire noise spectrum bandpass? Let's do a "back of the envelope" engineering guesstimate:

You need to reduce the power spectral density of the noise to or below the power spectral density of the signal. Power spectral density is measured in watts per square foot.

Watts (the undesired is stronger, goes proportionally):

db = 10 log Pi/Pr
How much does LightSquared transmit - don't know, keeps changing.
How much is the effective radiated power of a GPS satellite - there is a spec for that.

db = 10 log 15,750/300
db = 17.2

Square Feet (the undesired is closer, goes inverse square proportionally):

db = 10 log Rr**2/Ri**2
How far away is LightSquared - assume 1000 feet
How far away is a GPS satellite - assume 11,000 miles x 5,280 feet per mile
Surface of a sphere is 4 x Pi x radius squared
The 4 and the Pi factor out

db = 10 log (11,000 x 5,280)**2 / 1,000,000
db = 95.3

Attenuation required = 17.2 + 95.3 = 112.5db

If you have zero loss at the GPS bandpass, how much LightSquared signal attenuation do you need over the entire noise spectrum bandpass? Let's do this another way, using "the other side of the envelope" engineering numbers, but where do we get those:

Power level and orbital lifetime limit
http://gpsinformation.net/main/gpspower.htm

Which limits have been exceeded on the majority of satellites
http://www.glonass-center.ru/en/GPS/

Which is why it is not working well
http://www.raimprediction.net/ac90-100/summaries.php?id=npa_nobaro

But we knew well in advance that GPS was cratering
http://www.gpsworld.com/gnss-system/block-iif-follow-or-failure-7265

GPS is supposed to be at around -130dBm on the ground, might want to expect less.

LightSquared's lower, re-re-revised (they're going to turn it way up later, they admit) power level is -30dBm "near" their tower. Don't expect a definition of "near", and keep in mind that LightSquare keeps changing numbers.

Attenuation required = -30dbm - (-130dbm) = 100db

But what does this mean:

db is a log scale so 10db is a factor of 10, 20db is 100, 30db is 1000, 40db is 10,000, 50db is 100,000...

100db is, everybody get, 10**10 = LightSquared 10,000,000,000 times stronger than GPS, might want to expect stronger

112.5db is, everybody get, 10**11.25 = LightSquared 177,827,941,000 times stronger than GPS, by geometery ratio watts/foot**2

Really really really really big! Somehow, LightSquared accusing the PNT committee of being off by 32 times doesn't seem like much (only 15db)!

You can adjust the number down as LightSquared offers new lower power limits, and up as they increase the power as they claim they will. And you can adjust the number up as you decide on lower effective range limits (how far from the LightSquared tower your GPS should not work). You get the idea how this is done.

Hint, the antenna design will buy you something, which is not accounted for here, but not that much.

Hint, the DSP ability might be better than assumed, and this is the dimension where discovery and invention might make things considerably eventually maybe conceivably a little better far into the future.

Hint, the configuration might be changed to allow multiple lesser attenuation filters in series, perhaps separated by amplifiers, but no amplifier can be allowed to saturate from the off-band interference signal, and "sneak paths" for the strong interference signal around filter segments, such as in the power circuitry for the amplifiers, or the printed circuit board dielectric, will easily destroy this topology option.

Anyway you approach the problem of separating a small signal, like a flashlight on the moon, from a large signal, like a nuclear bomb detonation from 1000 feet away, you are going to have a big engineering challenge ahead of you. With LightSquared and every one else who wants to repurpose spectrum from satellite transmission to terrestrial transmission. Good luck, because we need a PNT system, and Loran has been terminated. It will probably be some other country's navigation satellite system which their military controls (Glonass (Russia), Compass (China), Galileo (European)).

eLoran was better than GPS for accuracy and for availability, only cost $12M/yr to operate, could not be jammed, worked where GPS did not anywhere within the confines of the 50 states and coastal waters. That was an M, not a B. Should be turned back on again (tell the Department of Homeland Security, they are demonstrably not paying attention).
http://www.loran.org/ILAArchive/ArchiveIndex.htm

Especially valuable is the link to your July 31, 2011 article with the timeline of the White House visit, the purchase of Sky Terra and and the political contributions.

Harbinger got burned a few years back this when it bought 20% of NY Times A stock (non controlling) for an average of about $13/ shareand sold it for between $6 and 8. No one in his right mind would buy that much stock unless he had information that NYT would be sold or the Sulzberger family would sell its controlling shares. Whatever his source, it wasn't very good.

Don't let this story get cold.