The Federal Communications Commission's initial approval of a troubled satellite venture came under fresh criticism Thursday as a key Republican lawmaker questioned whether the agency's actions could lead to billions of dollars in costs for taxpayers.
A U.S. Senator is asking hard questions about the costs of retrofitting GPS receivers to allow LightSquared to establish cellular channel adjacent to those used for the Global Positoining System. Although LightSquared is offering to pay for retrofitting the GPS receivers used by government agencies such as the FAA, there is no mention of how the company plans to compensate end users such as I for having to buy another GPS receiver.
AFAICT, LightSquared is hoping to create a house of cards that will stand just long enough to get past the current election cycle, and then commence ruining the most accurate source of location and time information available to consumers. I hope they fail.
I disagree. The frequencies in question have been allocated to LightSquared for a long time. Why should they suffer because consumer GPS manufacturers decided to save a few bucks on proper signal filtering?
As I understand it, Lightsquared was originally assigned those frequencies for use in a different, satellite-based service, and has now lobbied the FCC to change the assignments for use with a terrestrial application.
"Proper signal filtering" depends on having proper signals to filter, and the square-law rule comes into play: a transmitter one mile away has FOUR times more signal strength than one two miles away, all other things being equal. That means that GPS satellites, in orbit hundreds of miles above the earth and running on solar cells with severe power demands and low transmitted output, can't compete with a terrestrial service, no matter how "proper" the signal filtering of GPS receivers is.
In any case, even if the original assignments to Lightsquared had been for the service and power level that the firm is now attempting to have approved, I would argue that the GPS band deserves better protection than some idiot at the FCC was willing to provide for: consumer-grade receivers, in moving vehicles, trying to receive simultaneous radio signals from a constellation of GPS satellites need all the help they can get.
This whole thing stinks of inside influence, double-dealing, and political sleight-of-hand. I smell a rat, and I think that this is a back-room deal in the making.
Bill Horne wrote: :On Mon, Oct 10, 2011 at 08:02:00PM +0000, Thor Lancelot Simon wrote: :> In article , :> Bill Horne wrote: :> >
:> >AFAICT, LightSquared is hoping to create a house of cards that will stand :> >just long enough to get past the current election cycle, and then commence :> >ruining the most accurate source of location and time information available :> >to consumers. I hope they fail. :> :> I disagree. The frequencies in question have been allocated to LightSquared for :> a long time. Why should they suffer because consumer GPS manufacturers :> decided to save a few bucks on proper signal filtering?
:As I understand it, Lightsquared was originally assigned those :frequencies for use in a different, satellite-based service, and has :now lobbied the FCC to change the assignments for use with a :terrestrial application.
:"Proper signal filtering" depends on having proper signals to filter, :and the square-law rule comes into play: a transmitter one mile away :has FOUR times more signal strength than one two miles away, all other :things being equal. That means that GPS satellites, in orbit hundreds :of miles above the earth and running on solar cells with severe power :demands and low transmitted output, can't compete with a terrestrial :service, no matter how "proper" the signal filtering of GPS receivers :is.
:In any case, even if the original assignments to Lightsquared had been :for the service and power level that the firm is now attempting to :have approved, I would argue that the GPS band deserves better :protection than some idiot at the FCC was willing to provide for: :consumer-grade receivers, in moving vehicles, trying to receive :simultaneous radio signals from a constellation of GPS satellites :need all the help they can get.
:This whole thing stinks of inside influence, double-dealing, and :political sleight-of-hand. I smell a rat, and I think that this is a :back-room deal in the making.
Yeah, on the part of makers of consumer grade junk who have, for a decade, been making stuff that would not operate properly when an event they knew was coming (lightsquared turning on terrestrial service, which was approved in 2000 or 2001) came. Now, of course, they're whinning "We made and sold junk we knew was junk, because we knew we could count on our friends at the FCC and in congress to bail us out and protect the entrenched rent seeking of the existing wireless industry." Except, of course, they're not honest enough to say that, and instead spread fear among people who don't have a strong enough techincal background to know they're full of it, and are protecting economic interests at the expense of the public's.
And you would be 100% correct as we can read here:
" Allegations that we first made in February about White House " political favors for a company called LightSquared are starting " to get the attention they deserve. " " LightSquared is owned by the Harbinger Capital hedge fund, headed " by billionaire investor Phil Falcone. He visited the White House " and made large donations to the Democratic Senatorial Campaign " Committee. Soon after, the Federal Communications " Commission (FCC) granted LightSquared a highly unusual waiver " that allows the company to build out a national 4G wireless " network on the cheap. " " The deal has been criticized not only for its 'pay to play' " appearance but also because the LightSquared network would " interfere with the part of the wireless spectrum that is used by " Global Positioning Systems (GPS). " " On its iwatch news website, the Center for Public Integrity " published a blockbuster special report on Wednesday confirming " that LightSquared "pressed its case... at times citing its " fundraising for Democratic causes and President Obama..." The " report by Fred Schulte and John Aloysius Farrell is based on 300 " emails obtained by the authors under the Freedom of Information " Act. The emails contradict repeated denials by LightSquared and " the White House that the campaign contributions were related to " the FCC action. " " Meanwhile, the White House is facing accusations that it tried to " pressure an Air Force general to change his testimony on the GPS " interference issue. According to the Washington Post: " " GOP staffers of the House strategic forces subcommittee accused " the White House of trying to influence the testimony of an Air " Force general who was speaking about the project's potential to " interfere with the Global Positioning System, the satellite " network relied on by the military and private industry. The " staffers said Gen. William Shelton revealed in an earlier closed " meeting that the White House pressured him to include language in " his testimony Thursday supporting LightSquared's venture. " " The accusation that Shelton was pressured came at the same time " the White House was attempting to explain its role in the " awarding of $500-million loan guarantee to now-bankrupt Solyndra, " in which billionaire Obama bundler George Kaiser was a major " investor. " " Media coverage and commentary has been extensive, typified by " this observation by Chris Stirewalt writing on FoxNews.com: " " First there was Fast and Furious, then there was Solyndra and " now there is LightSquared -- three high-level scandals that " involve allegations of cover-ups inside the Obama administration. " " For a president who is already dragging an unpopular agenda " and low marks on his handling of the economy along the campaign " trail, this scandal troika is seriously bad news. " " On February 2, NLPC first made the allegation that Falcone's " campaign contributions helped grease the skids for the FCC action " in a letter to House Committee on Oversight and Government " Reform.
Additional info:
Obama Invested in Company That Got Sweet Deal From FCC
Will FCC's Political Favor for LightSquared Result in GPS Interference
Letter alleging Falcone's campaign contributions
***** Moderator's Note *****
BTW, there's more than one telecom angle to this debacle: Verizon, (and I assume other LECs) makes extensive use of GPS to provide Stratum II+ timing information for synchronization of DS3 and other DS-* rate signals between offices. If the synchronization goes away, so does the digital data.
GPS-driven clocks have, of course, "holdover" capability to compensate for brief outages, but they are NOT, in and of themselves, Stratum II timing sources, so any prolonged outage will cause them to lose synchronization and cause failures in digital data and digitized voice transmission.
If Lightsquared's use of "satellite" spectrum for terrestrial transmitters causes the GPS network receivers to become unreliable, then Verizon (and, possibly, other LECs) will have to replace the GPS-based timing sources with Stratum I atomic clocks, resulting in millions of dollars spent for engineering effort, hardware expense, transition planning, training, and implementation.
You know that Lightsquared is not actually using the GPS frequencies, or even their duly allocated frequency band closest to them, right? (Lightsquared voluntarily agreed to not use this band in their initial deployment, IIUC).
What the consumer GPS manufacturers are whining about are harmonics they certainly could have arranged to filter -- but chose not to, because it saved some bucks, likely both on the analog and DSP ends of the implementation.
All nice and good, and probably kind of true, but... I'd betcha that you could make some pretty similar allegations about a hefty number of Big Businesses, and Big Labor, and Big Banks, and lots of not-so-big ones... during this Adminstration, the previous one, and the dozen or three before them.
This may be bloody obvious - but since most state of the art military hardware uses GPS for so many things these days (Cruise missiles, drones etc.) - wouldn't you really not want transmitters capable of jamming GPS receivers indirectly, or if they were slightly modified, possibly directly jamming GPS receivers, on the market?
Wouldn't this give the "Terrorists" an opportunity to negate the massive technological deficiency some of them currently have?
It just seems slightly TOTALLY insane to consider allowing these things to be rolled out given their potential for that sort of use.
-- Regards, David.
David Clayton Melbourne, Victoria, Australia. Knowledge is a measure of how many answers you have, intelligence is a measure of how many questions you have.
***** Moderator's Note *****
Cruise missiles, by their nature, aren't in a particular area long enough to have their GPS or other guidance systems affected by a cell tower or cellular 4G mobile handset. Either they've vanished over the horizon before the taliban can key their jammer, or the possibility becomes moot in short order. ;-)
I don't know what other military devices or aircraft use GPS, but I think it's reasonable to assume that their designers took account of the possibility of jamming. It's a military use, after all.
OK, please bear with me: I'm going to have to delve into my radio background, both as a ham operator and a commercial radio technician, to explain the issues here.
This isn't a problem with harmonics: harmonic radiation from transmitters can't be filtered by a receiver, since it occurs at multiples of the assigned transmitter frequency and represents a separate, distinct radio frequency signal. Harmonics are either filtered out at the transmitter (by using a low-pass filter) or the problem is obviated by careful choice of oscillator frequency, transmitter design, mixing frequency selection, and other factors which have nothing to do with the receivers that the transmitter's harmonic radiation might cause interference to.
The issue in the Lightsquared case is a combination of something called *intermodulation* and another problem known as *overloading*. I don't claim to be an RF engineer, but I hope I can explain the basic issue well enough to make my concerns more clear.
I'll quote from a document shown at
formatting link
... in which the United States GPS Industry Council quotes a report issued by Garmin Corp. which states -
This application proposes to fundamentally change the usage of the L band 1 spectrum (1525 - 1559 MHz) from MSS (very low power, space to earth signals) to fixed, high power, terrestrial broadband service. The L band 1 is adjacent to the GPS band (1559 - 1610 MHz) where the GPS and other satellite based radionavigation systems operate.
Here's the basic problem with overloading: a receiver has to have enough "dynamic range" to filter out strong signals adjacent to the desired signal they are made to use, but must also be sensitive enough to properly receive the desired signal under adverse conditions - and it's hard to get more adverse than receiving a satellite signal in a moving vehicle. The energy being sent from Lightsquared's transmitters will overload GPS receivers in the immediate vicinity, since it's nearly impossible to design a receiver which is both sensitive (on the GPS band) and which has enough dynamic range to reject signals on adjacents frequencies which are, by reason of the fact that they are coming from transmittes hundreds of miles closer to the receiver than the GPS satellites, nearly impossible to suppress.
There is also a problem called "intermodulation": radio frequency signals can combine to provide _new_ signals that are equal to either the sum of, or the difference between, the two original signals. That means that Lightsquared's transmitters, sending signals in the 1525 to
1559 MHz range, can combine with signals from nearby taxicab, police, fire, amateur, fixed, and Citizens Band transmitters to produce new signals which are _in_ the GPS band, and will thus cause interference to GPS receivers as if a low-power transmitter had been deliberately tuned to the GPS band in order to jam GPS reception. It is impossible to filter this interference out at the receiver, because it would occur *IN* the GPS band.
It does us no good to say these frequencies were "duly allocated" to Lightsquared: it's just too big a problem to be solved by refering to a rulebook. Let's leave aside the fact that FCC rules _might_ have allowed terrestrial use of satellite frequencies in special circumstances: there is no satellite in orbit, and Lightsquared doesn't want to pay for one. The company is trying to drive a bus through a regulatory wormhole which is intended to allow companies that *have* paid for satellites to augment their coverage in certain limited circumstances, and too many businesses and people can get hurt to allow it to continue.
Re: Code of Federal Regulations, Title 47, Part 15 (47 CFR 15) Doesn't nearly every electronics device sold inside the United States which might radiate unintentional emissions [have to] be reviewed to comply with Part 15 before it can be advertised or sold in the US market?
If the above is true, won't LightSquared be brought to task to prove all of it terrestrial transmitting equipment [can] pass Part 15 before it can be sold/installed?
John
***** Moderator's Note *****
IANALB, as you point out, Part 15 covers /UNINTENTIONAL/ radiators, e.g., my laptop, since it has an internal clock oscillator that might cause interference to nearby receivers, must meet part 15 requirements. If Lightsquared is allowed to repurpose the L Band 1 spectrum for terrestrial use, then they would be operating under an FCC license, and thus not subject to Part 15.
There is no way to predict or prevent intermodulation interference to GPS receivers if Lightsquared's plan goes forward. That interference would be caused by the /combination/ of Lightsquared's terrestrial signals with those of other transmitters in other services, such as the Citizens Radio Service (CB), Amateur radio, or the various Public Safety and commercial licensees still operating in the 30 - 50 MHz band. All of the signals that might combine to cause "birdies" in the GPS band would be from licensed services, so the only way to prevent the interference is to stop Lightsquared.
The military uses a slightly higher power GPS channel (called P/Y/M code) off the GPS satellites and also uses jam resistant antennae, so this less a problem for the military.
It's a bigger problem for commercial safety services, like commercial aircraft, if the country was blanketed with Lightsquared transmitters, but less so from single ground based terrorists as the jamming source would need to be above the aircraft for most effectiveness.
Years ago I was on a team that developed timing solutions for CDMA base stations for one of the major infrastructure manufacturers. CDMA uses GPS time as a key part of the way it works. This means every base station must have access to GPS time. When I was developing the timing solutions, the accuracy was supposed to be +/- 3uS across a operating area (i.e. a city). The only way to meet this requirement was by putting a GPS timing receiver in each cell site.
Of course, we designed redundant systems, so we designed the system to support two GPS receivers. However, the other member of my team was an avid boater and radio geek. As such, he was very familiar with Loran-C. He knew that it was as accurate as GPS since both are traceable back to the USNO's master atomic clock in Fort Collins, CO. So, we designed the system to support a Loran-C receiver as a backup to GPS. If the system lost GPS, it would switch to Loran-C as a timing reference. Since it didn't drift relative to GPS, the site could stay up indefinitely on Loran-C.
Of course, the system had to start up with GPS in order to get GPS time, but once a GPS lock was established, it could switch to Loran-C and stay there.
It was a really elegant solution, as the Loran-C and GPS are at very different frequencies. So, the likelihood of weather system or an interferer taking out both was very low.
Unfortunately, our Government decided that Loran-C wasn't worth the $15 million or so it cost to run each year and shut it down a few years ago. Sure, GPS with WAAS can provide ships and other former Loran-C users with similar navigation data, but it sure was nice to have redundant systems that have very different interference profiles.
So, with the loss of Loran-C, the system I worked on now uses a local high accuracy clock for holdover if GPS fails. They are pretty good and can provide days of holdover time with low cost atomic sources, but nothing was ever as good as Loran-C.
-Gary
***** Moderator's Note *****
One of my friends, a ham radio operator who was also a Coast Guardsman, was once stationed at a place called French Frigate Shoals.
French Frigate Shoals is a coral reef in the middle of the Pacific ocean. When he was there, it had two major features: a high-power radar, and a Loran transmitter. He told me that he and his mates used to go shark fishing for entertainment.
For the benefit of those not familiar with Loran, it was a medium-wave technology which operated in the 160 meter band, just above the frequencies used by AM broadcasting in the U.S. to this day, i.e.,,
1.8 to 2 MHz. Propagation delays, atmospheric phenomena, and lightning all affected the performance of Loran, and those factors, in addition to the extraordinary power levels required for the transmitters, were some of the reasons for it being retired in favor of Inmarsat and GPS.
Although Loran was still in use during the time I was working on these sorts of issues at Verizon, it was, IIRC, not accurate enough for the timing we required. I don't remember specifics, but (again, IIRC) I think there was too much ambiguity caused by multi-path propagation for us to adopt Loran. Ah, well: sic transit technology.
You can still see Loran receivers on E-pay now and then. They usually include a broadcast reception setting, so they're still usable as conversation pieces that can receive baseball games.
I'm fairly certain that most of our military uses GPS, from grunts on the ground to ships to probably anything in the air (other than shells, at least for now :-). After all, GPS was developed to server our military's needs.
What most people don't know (it's not a secret), is that there is a second GPS band used only by the military. Using two bands allows the receivers to compensate for variations in the ionosphere allowing for a more accurate measurement of propagation delay from the the satellites. The end result is military receivers are much more accurate than civilian receivers (just how much is, of course, a secret). The second channel is encrypted.
Because of the second channel as well as minimal concerns about the cost to build a good product, I'm quite certain that it is much harder to jam a military GPS receiver than a $100 civilian receiver.
-Gary
P.S. For even more, look up "selective availability." GPS used to intentionally put jitter on the civilian channel in order to reduce accuracy. It was turned off after WAAS rendered it pointless.
***** Moderator's Note *****
Per Wikipedia -
formatting link
The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability.
AFAIK, Selective Availability is still a choice available to the military if circumstances warrant: if it's turned on, civilian GPS receivers are only accurate to within about 1/2 mile, which isn't enough to guide a bomb to it's target.
Just like the TCP/IP protocol takes care of the possibility of misuse, DOS attacks etc., after all, that was created for the military to be able to work even in the event of a nuclear attack, wasn't it?
........... I still don't believe that it's a good idea to require the manufacture of transmitters using frequencies near the ones the GPS devices use and have them available for commercial use. I still remember how easy it was to "hack" CB radios to use channels way off the official ones, and that was back in the 1970's!
The basics of any radio system - including GPS - is the requirement of a minimum S/N ratio to work reliably, having powerful transmitters in the vicinity of devices that have to receive tiny signals from a number of transmitters a long LONG way away to function (no matter how "directional" any antenna system may be) compromises that basic requirement. How long until the bad guys obtain and hack one of these things to directly jam military GPS devices? It will probably be a lot easier to obtain a commercial device than build one yourself.
Actually, with the right receiver, these issues could be mitigated. We used a specially designed Loran-C timing receiver that detected and handled multi-path signals and other noise like lightning (a "little" DSP goes a long way). We tested several sites by manually switching to Loran-C for timing and then monitoring the difference between Loran-C and GPS. Over the course of many days and weeks the difference stayed well within the specs needed to operate the base station.
Loran-C was an elegant solution for our system as it provided not only redundancy in timing [but also] redundancy by using very different radio signals.
I agree that technology moves on, however I think that Loran-C was shut down before its time. It offered a very valuable complement to GPS. Running at a very different frequency and being a terrestrial based service, it was subject to a very different set of issues that GPS. It was very unlikely that both services could be knocked out at the same time due to weather, jamming, or interference. My understanding is that Loran-C cost about $15 million a year to operate. Yes, our government needs to carefully manage our money, however Loran-C looked to me to be well worth the relatively small cost to the country.
I'll stop crying in my beer now.
-Gary
***** Moderator's Note *****
First, a clarification: the Loran-A system was retired in 1980, and that's the medium-wave version I mentioned in another note. Gary is writing about Loran-C, and long-wave version that operates at roughly
100 KHz. It's still in use in some parts of the world, but was retired in the U.S. and Canada in 2010.
As to cost: I'm not so sure of the $15 Million figure.
According to Wikipedia:
On 26 February 2009, the U.S. Office of Management and Budget released the first blueprint for the Financial Year 2010 budget. This document identified the LORAN-C system as "outdated", and supported its termination at an estimated savings of $36 million in 2010 and $190 million over five years.
No, it wasn't. That bit of revisionist history has been around for years, but it's wrong.
TCP/IP was designed to make a reliable network out of unreliable links, i.e., to leverage the voice-band data circuits of the
1970's. To accomplish that goal, the design team employed the concept of "store and forward", where each hop in a chain of links could retain packets and retransmit them again and again until the next hop confirmed that it had received a valid copy.
That is why there is NO minimum transit time specification in the IP protocol, and _that_ is why VoIP and other near-real-time applications have so many problems with latency: VoIP is only possible _now_ because data links are so reliable now compared to the 1970's. Military networks are all about transit time and hardening assets wherever possible, and TCP/IP doesn't fit in that mold.
The "store and forward" concept was applied to email messages, as well: every MTA (Mail Transfer Application) is capable of holding an email until the destination is available, sometimes for days. Although anti-spam measures have limited the capability, it's still available for use.
If you want proof that TCP/IP wasn't intended to be a military network, ask yourself why DOS attacks, spam, etc. are possible /at/ /all/. The answer is that the designers of the Arpanet were academics, _NOT_ military men! Their world view did not include the possibility that someone would break the rules for commercial gain, let alone for sabotage, and no competent military design team would leave such things out of a plan.
For the benefit of those not familiar with Loran, it was a medium-wave technology which operated in the 160 meter band, just above the frequencies used by AM broadcasting in the U.S. to this day, i.e.,, 1.8 to 2 MHz. Propagation delays, atmospheric phenomena, and lightning all affected the performance of Loran, and those factors, in addition to the extraordinary power levels required for the transmitters, were some of the reasons for it being retired in favor of Inmarsat and GPS.
I think the "current" version of Loran transmits at about 100 kHz. See the Wikipedia article or
I didn't remember the exact figure; that's why I said "about" $15 million. In government speak, I was very close. :-)
Even at $36 million a year, I think Loran-C was a bargain. I'd be amazed if GPS doesn't cost us taxpayers way more. And don't get me started comparing Loran-C to other things our government spends our money on...
If it isn't clear, I don't think Loran-C was outdated. I believe it was a great complement to GPS that provided a redundant timing and location service. But the OMB didn't ask me.
I believe the _operating_ cost of GPS is essentially -zero-. That basically all the cost is in the construction -- including the per-bird programming -- and delivery into orbit. There is a _tiny_ cost associated with maintaining the ground-based equipment needed to enable/disable SA, but, as far as I know, that's the only 'operating' expense.
***** Moderator's Note *****
The operating cost of any satellite-based system has to include the salaries and training of the controllers on the ground, and their equipment and its maintenance, and those costs are (excuse the pun) astronomical: the list is long enough to circle the earth.
There are teams of well-paid, professional specialists who spend their working lives keeping track of the space junk which might cross the paths of the satellites they are responsible for, and others who are always agonizing about what might happen if one of the solar panels goes dark, and groups of orbital planners who have nightmares about a
1% change in the Keplerian elements of the birds they're assigned to guide. Of course, that doesn't include the _actual_ operating staff for each satellite, i.e., the men and women who schedule the various tests that verify proper operating margins and antenna aiming and rate-of-spin and wobble. They monitor fuel budgets, respond to mission change orders, reposition both aerial and ground-based assets as needed, and keep track of all they do so that the Government Accounting Office knows they're doing their job.
The bills don't stop when the countdown reaches "zero". *THAT* is just the starting point.
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