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Last week, the fifth annual Symposium on Position, Navigation and Time was held at Stanford University. The “father of GPS”, Professor Brad Parkinson, warned of threats to GPS systems, including the threat from LightSquared.
As I feared, LightSquared has become a political basketball, with our Boy King trying to score 3 points. Mr. Obama’s DNC (Democratic National Committee) received a total of $90,000 from LightSquared’s owner, his wife, and its CEO. Subsequently, Obama’s FCC Chairman (and Harvard school chum) expedited approval of LightSquared’s controversial plan without conducting GPS interference tests or allowing sufficient time for public comment.
Mr. Obama, desperate for a success of some sort, apparently thinks that this is a quick way to both roll out wireless broadband and return financial favors. Mr. Obama invested $50,000 in SkyTerra (which later became LightSquared) in 2005, and in return a major SkyTerra investor contributed $50,000 to Obama’s 2008 campaign. Michelle Malkin details this in LightSquared: Obama’s Dangerous Broadband Boondoggle. Last week, A LightSquared vice-president threatened to sue the FCC if the FCC denied LightSquared’s plan to deploy its cell-tower LTE data network.
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It sounds like LightSquared is also becoming desperate. In my September article LightSquared’s problems highlight RF spectrum limits, I mentioned that the US military has opposed LightSquared’s plans, because LightSquared’s wireless signals will interfere with GPS (Global Positioning System) receivers. This includes E911 and aircraft navigation systems. As a quick patch, LightSquared has hurriedly proposed directional antennas for its transmitters, and stated that they’ll (at least initially) limit the bandwidth of their signal. It sounds like desperation to me.
GPS uses 1575.42 MHz, 1227.60 MHz, and 1381.05 MHz signals with CDMA modulation. I think that the first 2 frequencies’ signals are about 11 MHz wide. According to L-band authority Richard Abrahams, by the time the satellites’ 300 Watt signals travel over 11,000 miles and arrive at our GPS receivers they’re very weak — perhaps -125 dBm to -150 dBm. Because of size constraints, most mobile GPS receivers include antennas with minimum gain. The GPS signal that’s endangered by LightSquared’s plan is the 1575.42 MHz signal.
Apparently LightSquared has rights (inherited from SkyTerra) to use 1525 to 1559 MHz. (These frequencies were reserved for satellite use only, but LightSquared is trying to slip through an FCC loophole. As long as it maintains a functional satellite service, it may retain its FCC license to use 1525 tp 1559 MHz. It owns one geostationary satellite, SkyTerra 1.) Because their proposed LTE signal will be transmitted from cell towers at levels of up to 15 Kilowatts (that’s +72 dBm!) by amplifiers of less than perfect linearity, spurious signals from LightSquared’s signal will spread into the 1570 MHz region. These spurious signals, to GPS receivers, will be noise.
White House leaned on Pentagon to fudge testimony
Michelle Malkin, in a November 12 editorial titled Obama’s team of attorneys working overtime to block several scandals wrote
LightSquared’s advocates claim that the fault lies with GPS receivers with insufficient selectivity. They claim that a high-pass filter ahead of each receiver will work wonders. This is a pipe dream. Mr. Abrahams points out that the LightSquared transmitters will, because of the nature of LTE modulation and the difficulty of providing truly linear amplifiers at that frequency, transmit spurious signals outside their allocated frequency.
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The article Will FCC’s Political Favor for LightSquared Result in GPS Interference? sums up the many twists and turns in this story. It mixes complicated technical issues with politics. The timing of LightSquared’s largest investor Mr. Falcone’s contribution to the DNC (Democratic National Committee) one week after visiting the White House, followed by the FCC’s waiver is troubling.
Here’s the quid pro quo:
- Sept 22. 2009 · Philip Falcone and LightSquared CEO visit White House.
- Sept 29, 2009 · Mr. Falcone contributes $30,400 (the maximum allowed from an individual) to the DNC. Mrs. Falcone also contributes $30,400 to the DNC. (Later, in 2010, LightSquared’s CEO also contributes $30,400 to the DNC.)
- Sept 30, 2009 · Harbinger (Falcone’s hedge fund) and SkyTerra merger agreement is signed.
How Did LightSquared Get This Far Despite Bad Test Results?
For decades the FCC has been a political playground for lawyers and lobbyists with no technical knowledge. The current FCC, like the current administration, is the sad result of this slide into incompetence and corruption.
As a retired Western Electric physicist told me, “When MBAs and lawyers pretend that they’re scientists and engineers, we’re doomed.” Community organizers are even worse.
Further reading:
- How The FCC Plans To Destroy GPS – A Simple Explanation
- Will FCC’s Political Favor for LightSquared Result in GPS Interference?
- Politically-connected LightSquared Pushes Wireless Internet Plan despite GPS Interference Concerns
- Succinct summary: LightSquared Threatens To Sue, But Whom Would It Sue?
- Oh No! Not LightSquared Again! Still posing risks for critical U.S. infrastructure and national defense
Update · Nov 27 2011 · Inside GNSS article dated Nov 23: FCC Supplies FOIA Data Dump for LightSquared/GPS Interference Issue (Good Luck Finding What You Need Via the New Web Portal)
