LightSquared Disrupts 75% of GPS Connections In Government Test 197
Freddybear writes with this quote from BusinessWeek:
"Philip Falcone's proposed LightSquared Inc. wireless service caused interference to 75 percent of global-positioning system receivers examined in a U.S. government test, according to a draft summary of results. ... The tests worked off an 'extraordinarily conservative' threshold and didn't show the devices' performance was affected, [LightSquared exec Martin Harriman said]. 'If we're affecting the performance of the device — my goodness, we'd like to be sure that doesn't happen,' Harriman said. The laboratory testing was performed for the National Space-Based Positioning, Navigation, and Timing Systems Engineering Forum, an executive branch body that helps advise policy makers on issues around GPS. It found that 69 of 92, or 75 percent, of receivers tested 'experienced harmful interference' at the equivalent of 100 meters (109 yards) from a LightSquared base station."
This is being whitewashed from the white house (Score:5, Interesting)
This story is bad enough until you find out the white house was pressuring people to hide issues [hotair.com] related to LightSquared.
And Philip Falcone is a huge donor for the Democratic Party.
I'm not saying Republicans are angles or anything like that. I am saying this a very bad case of corporate ties directly to the whitehouse that is threatening to disrupt a major technology just to make some money...
Re:This is being whitewashed from the white house (Score:5, Interesting)
If it interfered with GPS, they'd get caught awfully fast and LOSE a lot of money. Interfering with GPS doesn't just mean that someone's turn by turn directions get messed up. A lot of things now depend on GPS, mostly for the time information.
Re:This is being whitewashed from the white house (Score:5, Interesting)
You forgot to mention that Phillip Falcone is under investigation by the SEC [washingtonpost.com].
Re:Farm GPS, airplanes, and who owns the bandwidth (Score:5, Interesting)
I'm not an expert, but read some back issues of GPS World. Lightsquared is doing dastardly deeds - this frequency was never intended for terrestrial broadcasting. They pulled a fast one and got this for a steal. The FCC screwed up big time - either incompetence or someone was asked to do a favor or paid off. There's a lot of FUD - Lightsquared has been planting stories claiming that the GPS devices won't work do to shoddy engineering. The facts are that they should be building terrestrial base stations that broadcast near GPS frequencies and not have to at least go through a thorough review and pay what this spectrum is really worth.
You don't see consumer electronics or their suppliers companies publicly complaining because it's not in their best interest to show a weakness at this time. e.g. if company A says that this will impact them, then company B can use that statement when they pay a visit or market to A's customers.
Fortunately this only impacts the good old USA. The rest of the world can continue to reap the benefits of GPS while they ramp up their systems. (Glonass has been on the rise. Galileo is finally making progress. Compass is on its way and hopefully they will eventually publish their ICD.)
Re:This is being whitewashed from the white house (Score:4, Interesting)
On the upside, the Military has just found an new way to jam the GPS of enemies on the battlefield.
On a more serious note, WTF, that has to be some serious bleed over. Almost all of the frequencies used by GPS are reserved government frequencies. Light Squared will use 1525-1559 MHz according to what I have found. The nearest GPS freq is 1575.42 MHz but is the L1 freq explaining why so many receivers get jammed completely. Light Squared has a serious engineering problem, because they either produce nasty sub-carriers outside there assigned frequencies, or they just ignore their assigned frequency and use more bandwidth that they have be allocated.
This link is to the a great Freq. Allocation Chart for the US. While it says 2003, it still applies to this case.
http://www.ntia.doc.gov/files/ntia/publications/2003-allochrt.pdf
Re:This is being whitewashed from the white house (Score:3, Interesting)
No interference (Score:4, Interesting)
They might be allocated the bandwidth, but this means they are responsible for interference. Of course they probably respect the FCC requirements, but they still need to consider interference, aqnd this one is an obvious case. Transmitting 42 dBm or so a few MHz away from a band such as GPS, and that on the scale of a nation IS a bad case of interference.
I expect the project to fail anyway because the handset manufacturers have no way to implement that band in a suitable phone with GPS.
This means expensive hardware in each compatible phone. Did you look at the RF HW of a typical phone ? it's a spagetti of PAs and filters. This band would mean passing from 2 RF paths to 3, 50% price increase. Furthermore, putting another antenna is hopeless, and the phone will jam it's own GPS, if available. Nobody in the industry wants such a monster, except Lightsquared.
For civilian GPS receiver, who are more sensitive due to a design nore vulnerable to interference (first LNA before the first filter), they will be affected. GPS performance will be unacceptable in some places close to antennas, and probably compatible handsets operating in the vincinity will affect them also.
Re:Not a surprise (Score:5, Interesting)
Here's the problem: You can block "Lightspeed" from deploying devices known to cause harmful interference to GPS signals. Big deal. What you can't do is make it "illegal" to jam GPS. Well, you can make it illegal, but it's a matter of enforcement. Expecting it to work 100%, especially in a battle field, is stupid. Your enemy will build GPS jammers by the dozen and hide them all over the place once they realize this is how you guide your missiles.
All I'm saying, is that this is a symptom of a larger problem: depending on easily jammed GPS.
I realize the military will just triangulate and find the jammers. But a jammer just has to hide their equipment in nearby hospitals and grocery stores, and use intelligent timing and antenna arrangements.... they can make triangulation a very difficult and time-consuming operation. And once the devices are found and destroyed, it's another $15 to deploy another one somewhere else.
I think it's a good idea to try and prevent what you can, such as by not certifying equipment that causes harmful interference. But let's not think this is the real problem with GPS...
Re:This is being whitewashed from the white house (Score:5, Interesting)
I'm an electrical engineer
Good
other was a guy who is claiming he has retrofit kits (RF notch filters) that will eliminate the interference. It should be noted that, when asked how his kits would be fitted to the millions of GPS receivers already in the field, the latter person had absolutely no answer.
Run the numbers on the Q factor required and the maximum possible passband attenuation to keep the noise figure of the front end usable... If you know what "snake oil" is WRT crypto it sounds like this guy's offering sounds suspiciously like "frequency grease" WRT RF.
Note that if the problem is front end overload, his snakeoil/freqgrease might be a simple 10 dB attenuator, probably being sold at an immense markup. If would be easier to duct tape aluminum foil to the existing antenna until the incoming signals are knocked down enough that the FE is not overloading but optimistically there is still enough RF signal left to decode.
This is assuming its not at the RF technology level of those stickers you put on cell phones to magically do things that sound good.
Re:You don't understand how this works do you. (Score:5, Interesting)
Now, now, the party of purple is equally corrupt in both its left and right branches. They only differ on what kind of corruption they specialize in.
But don't worry, come 2012, you'll get to pick which candidate from the party of purple you prefer, then spend the next 4 years crying yourself to sleep at night, because you know that no matter who is elected, it will be more of the same. And it will be same for your children, and your grand-children, and your great grand-children, who will work for less money that you earn on a Friday afternoon right now, and have less throughout their lives.
Remember to eat your bread and visit the circus on your way home. It's good bread, if a little stale, and the circus has giraffes. Repeat after me: "I live in the greatest country in the world! I worship authority! If I am struck, I will not strike back! The wiretaps are there for my freedoms, which everyone else on the planet is jealous of, and wants to take from me! USA! USA! USA! USA!"
you mean Dr. Javad Ashjaee (Score:2, Interesting)
You are probably referring to Javad Ashjaee. The guy is a GPS authority, with a long track in contributions to the community. He founded a few companies, the latest one Javad, which creates high quality precision receivers. He is someone who until two months ago, I would have never doubted. But then he started contradicting himself with his message. First, he started to complain how lightsquare does affect his receivers. Then he proposed ending the P-code as a way to mitigate for this (http://www.gpsworld.com/gnss-system/news/to-solve-lightsquared-issue-javad-ashjaee-calls-end-p-code-encryption-11887). The P-code is the encrypted signal that only military has access to. And now, he claims that there are no problems. While I kind of follow his reasoning, he needs to be more coherent in his message.
I mean, he first claims that something is wrong and proposes one crazy solution (ending P-code), and then another solution. So it is kind of like saying "they are messing up the signal, but this is great because now I can sell filters and maybe get some money from Lightsquare for supporting them".
The guys is still a smart dude and I wish him all best with his business. But my employer bought a receiver from his company for 15k and don't feel like spending a single cent more for fixing something that someone else broke. Lightsqaure is a good thing however. For precision receivers, this allows better availability of correction data for RTK measurements in cm-precise positioning.
So here is my opinion here: what Javad is saying *does* make sense in general. Please ignore his bad way of expressing this in the media, his apparent contradictions, his strong wordings that sound often arrogant, and let's try to understand his points, which are not that crazy after all.
Re:This is being whitewashed from the white house (Score:5, Interesting)
It's a sad commentary when good things come from parts of the system working at cross purposes, but it works.
I don't know; I see it as similar to a RAID array: every drive I purchase will fail, but by arranging my activities correctly, I will never lose data. Similarly, corruption may be present in all areas of government, but by arranging it just right it has made it more than 200 years. Current trends seem to indicate it won't make it to 300.
Re:Maybe the problem is with the GPS devices. (Score:4, Interesting)
1575.42MHz is first of all just the carrier frequency. All useful signals have a non-zero band width. Second, GPS receivers are required by design to not filter out adjacent spectrum because the actual received frequency will differ due to Doppler shift.
GPS signals are extraordinarily weak. The cell towers are over 1000 times as powerful as the actual satellites, and the satellites are so much further away, that the LightSpped signal at a GPS device is often a billion times stronger than the GPS signal. Considering how close the frequencies are that means that an incredibly strong filter is needed, and it must be designed to have near zero attenuation of actual GPS signals, since they are so weak already.
GPS receivers have historically been designed assuming that the nearby signals like those in LightSpeed's frequencies would not be substantially stronger than a GPS signal, since that frequency range was reserved for satellite communications. Even if they had been designed with LightSpeed in mind, it is virtually impossible to design a filter that would work and not harm the performance of GPS without substantially increasing the size of the receiver.
I'm honestly shocked that up to 25% of the receivers did not experience any interference. These were probably large receivers that already had excellent filtering, but which would be completely unsuitable for use in say a cell phone.