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Unless you're using frickin' laser beams, you can't completely block interfering signals. The concept you describe is a gross oversimplification of a CRPA antenna.

Interesting theory. Link: Pseudolite Quote: Pseudolite is a contraction of the term "pseudo-satellite", used to refer to something that is not a satellite which performs a function commonly in the domain of satellites.

Why pseudolites are used: Pseudolites preserve position information during GPS-denied conditions (June 2, 2016)

More info about the development of radio frequency position information:

Opening Up Indoors: Japan's Indoor Messaging System, IMES (May 1, 2011)

There are, of course, problems:

Danger, Will Robinson! Beware the IMES of Japan (Oct. 8, 2014)

Interesting theory. Link: Pseudolite Quote: Pseudolite is a contraction of the term "pseudo-satellite", used to refer to something that is not a satellite which performs a function commonly in the domain of satellites.

Why pseudolites are used: Pseudolites preserve position information during GPS-denied conditions (June 2, 2016)

More info about the development of radio frequency position information:

Opening Up Indoors: Japan's Indoor Messaging System, IMES (May 1, 2011)

There are, of course, problems:

Danger, Will Robinson! Beware the IMES of Japan (Oct. 8, 2014)

This might go well ... until the next solar storm comes that emits enough radio noise for cars to lose GPS satellite lock:

http://gpsworld.com/defensenew...

I wouldn't be surprised if auto insurance companies start putting in exceptions for that one, just like the 'act of god' clauses in home owners insurance.

It looks like the actual problem was a bad data upload; Specifically, some satellites were transmitting incorrect parameters for UTC offset correction. https://www.febo.com/pipermail... is the posting from a gentlemen at Meinberg that has the details. http://www.usno.navy.mil/USNO/... has more information about the time offset parameters (A0 and A1) and how they interact with GPS and UTC time.

According to another message (https://www.febo.com/pipermail/time-nuts/2016-January/095686.html), PRNs 2, 6, 7, 9, and 23 got hit. It is interesting to note that the satellite that was taken out of service this morning (PRN 32) is not in this list. It looks like the decommissioning of PRN32 was quite possibly scheduled (see http://gpsworld.com/last-block...), and even if not, a failure of that specific satellite could not have caused multiple satellites to start broadcasting incorrect offset data.

I'm really looking forward to the postmortem on this.

That was a planned re-retirement of a really old SV (launched in 1990!) in anticipation of next week's launch of GPS IIF-12.

The link in the article, to here, gives a much better description of the SP algorithm. In fact, it's a much more informative article, but it doesn't have a picture of a guy with a cell phone strapped to his face.

See http://gpsworld.com/origins-gps-part-1/

To promote their system, Russia decided to make new smartphones without GLONASS support illegal in their country -- so major manufacturers added that capability to all their phones (since there is almost no additional cost to each unit, once the capability is designed into the chipset). Not sure about CDMA chipset, since there is no major CDMA networking in Russia.

Would be nice if we got Galileo GNSS and Beidou support too, but I'm not expecting it to happen unless they pull a similar stunt with their markets (well, China might).

Why do you call it a stunt? I think requiring some kind of global navigation capability is fairly common and quite reasonable (think emergency services). Why not require, at a minimum, the global navigation system your country controls for phones sold in your country?

Newer phones have location chipsets that support both GPS and GLONASS. Do they figure out automatically that the GLONASS information is bad and switch to using GPS exclusively?

To promote their system, Russia decided to make new smartphones without GLONASS support illegal in their country -- so major manufacturers added that capability to all their phones (since there is almost no additional cost to each unit, once the capability is designed into the chipset). Not sure about CDMA chipset, since there is no major CDMA networking in Russia.

Would be nice if we got Galileo GNSS and Beidou support too, but I'm not expecting it to happen unless they pull a similar stunt with their markets (well, China might).

Old news. If you want a less sensationalistic, more technical discussion of how this is done, see this article http://www.gpsworld.com/drone-hack/.

In brief:
1) Yes, it's possible but there are a lot of issues that make it less than practical
2) It's a non-issue for military positioning systems, which use encrypted, time-stamped signals.
3) Experts are already aware of the problem and are working on solutions.

What issues make it less than practical? I read the article and I didn't see any major problems with doing it, nor did the authors.

As for "experts are already aware of the problem and are working on solutions", it reminds me of the last scene in the 1st Indiana Jones movie, where the Ark of the Covenant is being put into a seemingly endless warehouse. "Don't worry Dr. Jones, we have top people working on it". "Who?" asks Jones. "Top people".

Yes, it is possible to fix, but does that mean it isn't worth paying attention to? It hasn't been fixed yet. I also didn't find the article Slashdot linked to to be terribly sensationalistic.

Possibly, but possibly not. For one thing, the attack being shown here is far, far from news. And there are actually tons of ways to build a GPS receiver with the native ability to detect spoofing, and those features are standard for high-risk equipment (like classified stealth drones). But on the other hand, all of the details are classified in some way or another, so it's really hard to know for sure...but I doubt that it was all that simple as the attack shown here.

One simple way of detecting spoofing is by frequency strength. The most basic attack is to impersonate the satellites, and to be strong enough in output that the receiver is sure to pick up your "sats" instead of the real ones. But that typically means you're putting out a WAY stronger signal than you'd normally get from a GPS, and that ends up being a dead giveaway.

For military uses, the open and unencrypted C/A code GPS signal isn't even used; they use the more secure (and originally supposedly more accurate...but not really more accurate) P code signal (which now has a W code overlaid onto it as well). So there are inherent features involved in military GPS that act as anti-spoofing as well.

GLONASS is interesting because harware support for GLONASS positioning has been in some smartphones since 2011, and it will become very mainstream this year. I would also expect to see personal navigation tools supporting GLONASS as well as GPS this year. More satellites means a better fix, and it isn't very expensive to do.

So, in the future your vehicle tracking might use a combination of GLONASS, Galileo and GPS using a much broader frequency range than just GPS alone.

http://www.gpsworld.com/gnss-system/expert-advice-mss-misinformation-and-ten-truths-12353

The FCC turned up its nose at assertions by some that the entire process was conducted in near-stealth mode as well as on an admitted fast-track, filed during a period coinciding with Thanksgiving and winter holidays so that it would pass with little notice. "We conclude that the pleading cycle for LightSquared's request - in which the Comment Public Notice was issued on November 19, 2010, with comments due on December 2, 2010, and reply comments due on December 9, 2010 - is sufficient for the decisions we make herein."

You're describing the way the system should act, ignoring the way it does act. In 2007, a Navy jamming exercise that jammed GPS disrupted cell phone service (and several other services) in San Diego. http://www.gpsworld.com/defense/gps-insights-april-2007-8428

Came across a couple of articles recently here and here specifically talking about GPS interference and "dead-zones".

Curious part, is that this technology is APPROVED by the FCC. The frequencies used by LightSquared (1525 MHz—1559 MHz) is just below the GPS frequencies (1559—1610 MHz). While it SHOULDN'T interfere, the power levels used by LightSquared is much higher than the signals from satellites.

The FCC will appreciate that I'm sure.

Crank it up to 1500 watts, like LightSquared is doing, and the FCC will give you a license and a favorable press release.

Thanks to cronyism at the FCC, we're about to start jamming GPS everywhere, on a perfectly legal basis.

This is what happens when you hire politicians to do engineering work.

Check out the FCC's fast track of LighSpeed's high powered ground based transmitters in the satellite band right next to GPS. Not even any buffer space for 40,000 transmitters authorized to run an effective radiated power of 45,000 watts. It can cause interference (loss of signal) to ground based GPS (automotive) in cities to over 3 miles and aviation GPS (complete loss of signal) at over 5 miles. Isn't that a comforting thought with most aircraft now using GPS for instrument navigation. Watch for line wrap on link. http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029 Even the comment period was far shorter than normal with the FCC giving the OK against the wishes of the Department of Defense, Department of Transportation, and Homeland Security. it was also against the FCC's own policy. Lots of conspiracy theories about this one. :-)) According to the article LightSpeed *apparently* expects the GPS community to fix the problem and not them. They are also the ones who will turn in any report to the FCC on a study of interference to GPS. Basically if they get their way anything presently using GPS would likely need to be either upgraded or replaced which includes all modern cell phones along with both automotive and aircraft GPS receivers.

That company would be LightSquared, there's several govt agencies that are hopping mad and there's all kinds of management types in Washington DC engaged in meetings on how to mitigate this situation. How this was approved by FCC, apparently someone didn't do their homework.

Data Shows Disastrous GPS Jamming from FCC-Approved Broadcaster
http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029?utm_source=GPS&utm_medium=email&utm_campaign=Navigate_01_31_2011&utm_content=data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029

I sometimes wonder if this country is losing it, as in the big rage to go all 700MHz digital trunking for public safety 2-ways. For rural areas, well lots of luck with that.

Even the hamsters have groups getting into the same kinds of mischief such as repeater coordination organizations getting into the spectrum management role and claiming they have FCC and ARRL approval (which they do not). And one such group stated all amateur repeaters and users of them have to go narrowband (hey A******, do your homework and you'll see it applies only to Part 90 users!!!!!!!!!)

Alrighty folks, that's my Gripe Of The Month.

500 MHz of which spectrum? 4GS may already be colliding with GPS. http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029

From a GPS World article:

The consumer GPS device began to be jammed at a power level representing a distance of 3.6 miles (5.8 kilometers) from the simulated LightSquared transmitter. The consumer device lost a fix at 0.66 miles (1.1 kilometers) from the transmitter.

The Federal Aviation Administration (FAA)-certified aviation receiver began to be jammed at a distance of 13.8 miles (22.1 kilometers) and experienced total loss of fix at 5.6 miles (9.0 kilometers) from the transmitter.

The bottom line is that if this goes through, GPS receivers will get more expensive due to the additional filtering, and existing receivers will operate in a degraded mode.

On January 26, the FCC waived its own rules and granted permission for the potential interferer to broadcast in the L Band 1 (1525 MHz—1559 MHz) from powerful land-based transmitters. This band lies adjacent to the GPS band (1559—1610 MHz) where GPS and other satellite-based radio navigation systems operate.

This system does in fact affect GPS receivers from the big names in GPS navigation. Initial tests by Garmin and Trimble show at least 0.6 to 5 miles away from a transmitter tower a GPS receiver will loose the ability to lock onto a signal reliably. With jamming and degiration present at 3.5 to 14 miles. It is not just a Garmin/Timble problem, this will affect ALL companies GPS receivers.

With at least 36,000 transmitters planned for the US this will affect you if you use GPS for navigation. That is on average one transmitter for every 82 square miles at launch, with more to come. In urban environments there will obviously be more transmitters placed along major roadways and in congested city environmental where GPS is already hard to receive.

Even WAAS grade aviation GPS receivers which are required to be more sensitive are susceptible, this poses risks for pilots using the system to fly and passengers traveling aboard aircraft navigating with GPS. These GPS receivers are certified to FAA approved levels and are designed to tolerate high levels of interference. Additionally it will affect the service and reliability of the FAAs next-gen ADS-B system that is scheduled to replace radar by 2020 since air traffic control will be dependent on the aircraft telling it where it is using GPS. (look at Wikipedia on ADS-B for more details)

Please URGE the FCC and congress to push back against LightSquared, protect our valuable GPS resources.

Here is GPS Worlds Article:
http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029

Letter to the FCC from Garmin and Trimble:
http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030

This system does in fact affect GPS receivers from the big names in GPS navigation. Initial tests by Garmin and Trimble show at least 0.6 to 5 miles away from a transmitter tower a GPS receiver will loose the ability to lock onto a signal reliably. With jamming and degiration present at 3.5 to 14 miles. It is not just a Garmin/Timble problem, this will affect ALL companies GPS receivers.

With at least 36,000 transmitters planned for the US this will affect you if you use GPS for navigation. That is on average one transmitter for every 82 square miles at launch, with more to come. In urban environments there will obviously be more transmitters placed along major roadways and in congested city environmental where GPS is already hard to receive.

Even WAAS grade aviation GPS receivers which are required to be more sensitive are susceptible, this poses risks for pilots using the system to fly and passengers traveling aboard aircraft navigating with GPS. These GPS receivers are certified to FAA approved levels and are designed to tolerate high levels of interference. Additionally it will affect the service and reliability of the FAAs next-gen ADS-B system that is scheduled to replace radar by 2020 since air traffic control will be dependent on the aircraft telling it where it is using GPS. (look at Wikipedia on ADS-B for more details)

Please URGE the FCC and congress to push back against LightSquared, protect our valuable GPS resources.

Here is GPS Worlds Article:
http://www.gpsworld.com/gnss-system/news/data-shows-disastrous-gps-jamming-fcc-approved-broadcaster-11029

Letter to the FCC from Garmin and Trimble:
http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030

WASS is used to provide corrections to upper atmospheric disturbances in the GPS signal. It works like this: you have a lot of beacons on ground, mostly close to the shore but pretty much everywhere in the country. These stations know *exactly* where they are, but they anyway measure their position via GPS. By looking at the difference between what GPS says and what they know, they calculate the effect of these atmospheric disturbances. These are uploaded to a central system and get in turn broadcasted via WASS. WASS signals get used mostly by air and maritime vehicles in the North America. Europe has something similar called EGNOS, that depending on the country it could be used with limited advantage on terrestrial measurements. In Germany for instance, the angle to EGNOS is about 20 degrees which makes it almost impossible to capture free-line-of-sight by anyone that is not airborne or in open waters. Now back to the issue. One WASS satellite is failing. There are two WASS satellites and we are fortunate that the one about to fail is not the most important one. This link has some nice images showing the coverage. Sorry for copy-pasting, it's my first post and don't know how to add tags yet. http://www.gpsworld.com/gnss-system/augmentation-assistance/news/failure-imminent-waas-geo-satellite-9841 The problem is that airspace people don't like single point of failure so having one satellite only is a yellow lamp. How this will affect air traffic is still to be seen. GPS accuracy is about 16m with a good view, and when traveling 200 mph during approach, this is not crucial if you ask me. Maritime is something different. You don't wanna sail in Sweden and hit an underground island because you are 10m too far left. For final approach to runway and landing WASS has never been an enabling technology, so business as usual. The US will either replace the satellite or bring the functionality to another one. Until then, people must know that WASS could be out for a few seconds every once in a while. Nothing new really. None of us here will probably feel anything particular happening in the sky.

You've put me in a difficult situation explaining this to you since it appears you read the title but not the summaries or the articles, yet somehow knew that this is a commercial communications satellite. Here's a linky with details on how it *does* have something to do with GPS: http://www.gpsworld.com/gps/news/waas-broadcasting-satellite-having-problems-9810

Since I can't be sure you will read TFL, here's the first paragraph that you probably won't read either:
Intelsat S.A. announced they lost control of their Galaxy 15 (G-15) satellite. G-15 (PRN 135 to GPS users) is one of the two Wide Area Augmentation System (WAAS) broadcasting satellites (GEOs) that broadcast GPS corrections for aviation and ground users all over North America. Despite the Intelsat announcement, the WAAS payload on G-15 is still broadcasting corrections.

Are there any other sources we can provide that you also won't read?

the FCC has not done anything to fight interference for years. Hell most Pirate FM stations don't get taken down until they become big and obvious. They dont raid homes over Wifi violations.

They probably wont do anything unless they receive a complaint, but they certainly do investigate interference. Check out this article from GPS World. Several malfunctioning amplified TV antennas were jamming GPS signals in a California harbor. The FCC investigated and rectified the problem. No mention of whether they entered anyone's property against their will (the interference was accidental so I'm sure the individuals cooperated), but I can understand why they have this power.

> There have already been dual GPS/GLONASS systems for many years, so a triple GPS/GLONAS/Galileo system should be no problem.

Actually, such systems already exist. For example, see Topcon GR-3. There are also GPS/GLONASS/Galileo single-chip receivers.

My Verizon Treo 650 came with the default of transmitting its location data all the time. Fortunately, there was a (somewhat buried) option to turn it to "911 only". Of course, if you read the above link, you'll see that the cell company can get a pretty good handle on my location if they wanted just by triangulation anyway.

Receivers that use both GPS and GLONASS satellite signals have been available for years. Maxim just announced a new receiver chip which receives both and only costs $2.95 in quantity, so that capability is likely to become more available.

GLONASS was in bad shape after the USSR tanked, but new GLONASS satellites are being launched again, and the constellation is currently about half populated. As of today, 11 GLONASS satellites are functioning, 5 are down, and one new one is being brought into position. 24 operational satellites are a full set.

The earlier GLONASS sats only had a two year design life, but the latest models have a 7 year design life, and they're going for a 10-year model. They launch a new batch every December, so they're starting to catch up.

Although it's a lot of fear-mongering so far, if the moratorium is lifted, it would not be against federal rules to let a state or a municipality start taxing the intra-state email (although I fail to see how it would be possible to collect/enforce fairly).

States and municipalities are pretty darn'd good at dreaming up taxes right now and I wouldn't put it beyond some of them to tax corporation an assessment based on how many employees there are or tax broadband providers based on how many customers they had (although in the latter case, I'm sure they'd let them pass the surcharge to the subscriber). If you look at your telephone bill or cable bill, you'll see what I mean. I doubt there would ever be a per-email tax (for instance, how could you really tell web-mail from e-mail an define it properly w/o a loophole), but you could certainly get socked with a per megabyte of bandwidth consumption tax.

For instance, oregon, faced with the possiblity that better fuel economy would make increasing per-gallon tax on gasoline unfairly regressive to folks that must drive older cars that get worse gas, is looking into a GPS-based road tax...

Most of this urge to tax telecom is coming because of fear. Traditionally, local governments were able to shake down the telephone and cable companies for money by offering monopolies in exchange for access to the public right-of-way (e.g., to dig phone trenches and stretch coaxial cable), and a host of free or discount use of services (e.g., anyone remember public access cable, that's what we used before YouTube). With the telecom revolution bringing in many new players that don't have to bow before the local commissioners, local governments realize that the "monopolies" they were granting aren't really that valuable anymore and going forward it'll be hard to continue to shake-down these big companies and that the price of revenue enforcment will go up (can't just rely on the monopoly cable or telephone company to write them a check every month for the tax collection). As the cost of revenue enforcement goes up, so does the tax rate to compensate. Since they can't go that regressive on the taxes, they need to find new revenue streams (it's easier politically to tax the "rich" than the "middle-class" and the "poor"). That's were we are right now.

Here's some more info on the subject...

Gordon Brown

My personal belief is that it is the electronics and data mining companies who want to create new markets for their data analysis tools, which would allow data to be resold to all sorts of markets (insurance companies, retailers, security agencies).

You might be right. According to this article, and another article, increasing fuel efficiency is leading to declining tax revenues from existing fuel taxation, that by 2014 would not be sufficient to maintain the road network in Oregon.

Gordon Brown

My personal belief is that it is the electronics and data mining companies who want to create new markets for their data analysis tools, which would allow data to be resold to all sorts of markets (insurance companies, retailers, security agencies).

You might be right. According to this article, and another article, increasing fuel efficiency is leading to declining tax revenues from existing fuel taxation, that by 2014 would not be sufficient to maintain the road network in Oregon.

That's pretty interesting.

Actually, systems like the Japanese one are really the sort of alternatives I was proposing to the wheel-reinvention of simply making "another GPS."

From an an article on Japan's system, "although the QZSS is seen primarily as an augmentation to GPS, without requirements or plans for it to work in standalone mode, QZSS can provide limited accuracy positioning on its own." That seems like a good approach, which the Europeans might want to consider. Rather than simply pretending GPS doesn't exist, it augments it when available, providing an enhanced level of service and enabling new applications. (*cough* self-driving cars... *cough*) However it could also fall back and provide actual positioning in the absence of GPS if really necessary. (Although the Japanese don't seem particularly concerned in that regard, it shows that such a system would be capable of it.)

If that's the kind of system that China is building, then more power to them; I think the Europeans would be smart to follow the same path. Although actually, what would be best, is if the various national governments making their incompatible national GPS-augmentation systems, agreed on a univeral standard (or at least standard frequency band, so the receivers could be physically the same). Probably wishful thinking there, but a system like that would probably lengthen the life of the current-generation GPS system while providing the kind of accuracy that won't be available worldwide without a huge investment in new satellites (GPSIII).

I was messing around on a friend's boat last May and turned on the LORAN receiver. Lo and behold it displayed a set of valid coordinates.

LORAN lives! (Well for a few more months anyway.)

http://www.gpsworld.com/gpsworld/article/articleDe tail.jsp?id=314650

And I think it is used more widely in the non-US, non-EU parts of the world.

The Euro-peons are thinking about using the Galileo system as part of an electronic road tolling scheme... So, bearing in mind the surveillance potential of such a scheme, I'd think the best way to "crack" one of the Galileo satellites would be an ASAT missile...

Ohh, those silly Europeans... that kind of thing would never happen in the US!

Hint: spending billions requires a real payback somewhere down the road:

Galileo is seen as an instrument of EU independence that will also help sell French weapons. As things stand, France cannot sell GPS-supported arms outside of NATO, explained another source. This leaves out a substantial number of potential customers, and France needs to reach out to other markets -- in fact, it has made securing new arms markets a part of its national policy. http://www.gpsworld.com/gpsworld/article/articleDe tail.jsp?id=63243

Yeah, that'll come in handy for Chinese missiles.

http://www.gpsworld.com/gpsworld/article/articleDe tail.jsp?id=21977

I really wonder what the implications of this are if the US squared off with China over Taiwan for example. I don't really have a problem with the EU wanting to have an "ndependent defense identity" or whatever, the problem is if it ends up giving a leg up to China or North Korea, or even Iran in a future conflict with the US. Since EU countries would either be on the same side as the US, or neutral this would be seriously self defeating. Actually, I do have a problem with the EU buereacracy's implicit assumption that the US is a strategic competitor, since it could develop into a very dangerous rivalry in the long run, and no one in the EU has ever voted on this policy.

Galileo has a bunch of advantages over GPS, like being designed to work to a higher degree of acuracy and to work inside buildings and in built-up areas. Take a look at this article http://www.gpsworld.com/gpsworld/article/articleDe tail.jsp?id=61295 for more information.

wired

GPSWorld

US Mission to the EU

Why do you need newer and fancier GPS satellites when you can just use satellite television signals.

The way I understand it, the system uses GPS and "cell ID" technologies to determine the position. In theory this would give much better location information, if done correctly. But I have no idea how well this is working in practice.

Here's a story about this "Assisted GPS. Apparently one of the main advantages isn't actually accuracy, but reducing the "time-to-first-fix", which would be on the order of 20-60 seconds from startup to the time the first GPS reading is available assuming an unobstructed view of the sky.

After reading this article it becomes much more clear to me why the GPS receiver in my phone can't be used as a standalone. I thought it was that it was intentionally crippled so that the phone company could control when it is used. But it's apparently more an issue of power consumption than anything else, as well as I suppose the cost savings of not having all the calculation circuitry built in. It'd still be nice if I could somehow access the raw data, though.

So put your phone out in the open for a few minutes before installing. Unless...

centimeter accuracy using indoor differential gps

http://www.gpsworld.com/gpsworld/article/articleDe tail.jsp?id=3086

Hmm. My Internet connection is acting up, making searching a pain. The best I've come up with is this quote from Global View June 2004:

``A key point of contention was whether the Galileo open signal would interfere with the new GPS military signal and the ability of U.S. military forces to jam civil GNSS signals -- including Galileo -- in a theater of operations.''

I know story dedicated to the US jamming Galileo is out there, but I can't find it at the moment.

That, or just jam the GPS device.
Wouldn't help you open Rights Management stylee protected data, but it would stop your laptop from screaming "I'm being stolen!".

Do you have any sources for this? The way I understood it the timing on the shared channels was done in such a way that interference between gps and galileo was negligable.

Here's [PDF file] a good article about the technology.