Testing of new wireless network could cause GPS outages

It won't be independent of any provider . . . Lightspeed will simply become another provider . . .

Given the capital they have raised, you can be sure that they'll be fighting tooth and nail to get the right to deploy - interference or no interference.

From what's been discussed, the likelihood of compromised GPS operation is quite high - but you'd think that those tests would have been run outside of an urban center.

Hopefully the government will act responsibly and will promote the tests and provide guidance to the public using newspaper, television and radio announcements.

Who among us would actually know that our GPS receivers were behaving badly only after midnight and so on, because of interference? In fact, how many of us are out there at that hour at all (OK, maybe in Vegas)?

I find it odd they're running the tests after midnight, when all types of GPSr traffic will be lowest.

That tells me they are anticipating interference, and are trying to mitigate the fallout. They better get it right the first time, or people may die.

I agree with this comment,why don't they do it during the day in real world settings.I believe they (lightsqured)already have permission to set up their system,I believe they are having to test it because all of the protest from people or groups like POI Factory.

I think it makes sense to do the test at a time that critical use of gps such as air traffic control and emergency responders is at a low. That way if there is a disruption to gps signals, there would be less chance of life threatening situations occurring due to the test.

And I would bet that there will be monitoring of the effect on “real world” gps units at actual air traffic control and emergency responder sites, plus monitoring of other less critical gps receivers.

It would be irresponsible to do such initial testing at a time of heavy critical usage of gps units.

I made my comment about day time because I thought they might get a more accurate picture of what is happening if it does indeed mess up the GPS signal,I agree I don't want any one hurt but what happens if they test it at night and everything is ok and then they put the system in and it messes up the things you spoke of.

If it works at night while monitoring a lot of gps receiver types and locations, it is less likely that there will be a problem during heavy critical usage.

If it does cause a problem with critical receivers at other times of day, I would bet that FCC will immediately shut down the offending transmitters.

Thanks for the heads up, I knew LightSquared was starting testing soon but didn't know where. Now I know Las Vegas news is the place to look to read about potential interference. Time to buckle in for reading about the latest FCC failure.

After they finish in Las Vegas, next should be a daytime test in DC and NYC. Let the FCC explain to the Pols why their limo drivers are lost.

I couldn't find any report of any problem so far. Modern electronics does marvel at channel separation. I would be interested to see any report of issue during these tests.

I doubt they would be publicly announced. You know... for the good of the public and all that.

very funny!!

my only question is..
why it affects GPS ONLY when it fails?
if it causes interference (haven't heard of that) to GPSr device, it will regardless success or fail.

sounds to me like a April 1st news.

I'm about to go to LV, and I don't want anyone to mess with my GPS

You probably won't find any publicly released documents until after the June 15th report to the FCC. However, initial reports from "boots on the ground" reported a couple of issues. One is only one of the two proposed bands had been tested and there is localized interference detected. The testing with the other band, and with both bands hadn't been carried out as to the report I had received, When both bands are operating at the same time is when the majority of the interference is expected.

The other issue reported was the amount of power being used during the test. It was reported LS was using only 1/4 of their stated power level (400 W vice 1,600) and proposed to "interpret the results of problems with using full power."

The tests done at Holloman AFB were observed by the NM State Police and a local fire department. The NM State Police reported it wasn't so much the interference to the GPS receiver that was the issue (other than it being unusable) it was the other systems which depend on the timing signals from GPS that were affected long after signal returned. Often, the only way full functionality returned was by shutting down all the systems in the patrol car and then bringing each one online through a phased startup.

It doesn't sound like the test bodes well for FS. Regardless of what the FCC says, I doubt this will go far when it interferes with the police's equipment.

it is odd that they running the test at night

They are running at night for 2 reasons, 1 is valid.

The tests are being run from midnight to around 4AM. It's light traffic at the airport. The 2nd reason is bogus, they say it's because public safety demands are lighter. The hours between 2 and 4 are some of the busiest hours for public safety. The drunks are out, the criminals are out and the world is skipping along with its handbasket in most metro areas.

You forgot the 3rd reason: They believed this would impact the least amount of (other) equipment out there as most would be active and in use only during the normal daytime work hours. This way they can turn around and say afterwards "See? Nothing was impacted or disrupted during our test".

Nice to see though that even at 1/4 the transmission power, its already affecting equipment.

Senator Chuck Grassley (R- Iowa) issued a press release yesterday announcing that he is seeking transparency and disclosure from the FCC on its handling of the LightSquared matter.

• "This project is controversial for two reasons. One, there are questions about whether it will block GPS technology, which is important to agriculture and other industries. Two, the principal behind this project is said to be under investigation by another agency for his financial dealings," Grassley said. "The FCC's unusual fast-tracking of this project before its effects have been fully tested raises questions about whether the agency did its due diligence. I'm looking for answers to these questions so taxpayers can be assured that the government is treating public property the way it ought to be treated. So far, the FCC hasn't provided any of the information I've requested. It should, in the interest of transparency in doing the public's business."

Bloomberg, The Hill and Communications Daily reported on the Grassley letter. Communications Daily included comment by LightSquared:

• "We respect Sen. Grassley's interest in ensuring this is done properly, and we believe that Congress and the FCC, working together, can help bring more innovation and competition to the wireless market in a way that works for consumers and competitors alike."

TR Daily and Communications Daily both reported that representatives from LightSquared and Trimble discussed GPS interference from LightSquared’s planned network at a National Public Safety Telecom Council meeting yesterday. In urging members of the public safety community to become involved in the matter, Jim Kirkland of Trimble warned of the “extremely accelerated” FCC process, the scope of likely interference, and pointed out that the equipment being used in testing transmits "about a fourth of the power" that LightSquared would be authorized to transmit. LightSquared’s Jeff Carlisle focused on the efforts of the FCC-mandated working group that is studying GPS interference issues and denied some of Kirkland’s points, saying that “there is no imminent possibility” the company will deploy equipment more powerful that what is being tested.

Both stories mentioned the efforts of the Coalition to Save our GPS. The TR Daily story noted the Grassley release as a related development.

Citing Gen. William Shelton, Inside Missile Defense reported that the Air Force remains concerned over potential GPS interference caused by LightSquared.

This article kind of explains it all.

http://tinyurl.com/3fk5nu6

@Evert Sadly, that is a bet you would probably lose. The FCC is determined to get LS going whatever the cost or damage. In days past, the FCC would shut down any transmitter that cause interference to a service. These days, unless you are running a low-power pirate FM broadcast station, you are probably safe.

@abin It only affects GPS because GPS is the service adjacent to LightSquared's frequencies. If LightSquared were operating, for example, in the 700MHz band we would be talking about cell phone interference.

FCC usually deals with Radio Frequency Interference by determining which equipment is at fault – the “offending” transmitter or the offended receiver.

If the RFI is caused by strong harmonics outside the transmitter’s allocated frequency, then the FCC will require that the transmitters be fixed. If the RFI is happening because the receiver is not properly filtering out adjacent bands, then the onus is on the manufacturer of the receivers to change their design.

But of course either “fix” can take time to implement. Whether or not a out-of-spec transmitter must be shut down until the fix is made depends on the situation.

In the case under discussion, I still would bet that the FCC would shut down any transmitters near critical receivers even if the RFI problem were due to poor design of the receiver.

And even if we all have come to think our gps receivers are “critical”, the FCC probably would not. If the receivers need to be re-designed then we will have to suffer the interruption and buy new ones when they become available.

What Aardvark is saying is true, up to a point. It isn't as much the FCC that is pushing broadband, it's the White House. The National Broadband Plan was drawn up at the request of the White House. They are the ones that determined 500 MHz of spectrum was needed to satisfy the immediate demand for commercial carriers. Broadband to the rural areas is the smoke screen they are using to push their plan to pay for a lot of the programs that have been put in place. Do like Bill Clinton did, free up some spectrum and sell it to the highest bidder with the money going to the treasury to pay for the new programs and entitlements.

The reason LightSquared slipped through - forget about having only 10 calendar days to comment on their petition - was it being done through the International Bureau which normally only deals with cable landings on US soil, international radio broadcasts and, oh yes, those satellites up in the sky. When XM and Sirius got started, they requested and received a waiver to put land based transmitters operating in the frequencies used for satellite downlink. This was to extend their satellite service and provide service in areas that would normally not have good service because of blockages or reflections like urban canyons.

This is the spectrum being used. It's not only Sirius/XM, but other downlink spectrum that was sitting in a broad swath and could be used for broadband data when the right technology came along. That technology is LTE. LS has split thie spectrum into at least two parts, each having a minimum of 5 MHz, but most often more. One piece is outbound, the other inbound. The system LS is building will use both the inbound and outbound sections at high power (1,600 W) to insure the maximum data rates between sites. Their partners would connect to the transmitters at each tower (as needed) using LS to carry their programming material which can include Internet access. The amount of spectrum LS has control over is a big piece of the 500 MHz the White House wants.

The International Bureau really does have engineers on staff, but they were overruled in order to meet the White House's demand for the spectrum. The 5 Commissioners (well, 4 right now) have 3 of one party, and two of the other. Right now it's a 3-1 split.

The issue over interference is now being monitored by several different committees in Congress, and they are demanding the FCC rescind the waiver. The problem with Congress is again the House/Senate split. The FCC is a legislative body, meaning it was created by Congress and is supposed to answer to Congress not the Executive Branch or White House. It will take a law passed by both houses of Congress to stop the waiver unless the FCC acts on its own to rescind it.

As to the interference, the testing is being done with special antennas being provided to the receivers under test. These antennas have additional filters to limit the out-of-band signals from LS. These antennas don't filter everything, and they can only be installed on fixed sites right now. The GPS receivers in cell phones and your navigation units also require either new chips with the filters installed or external filters. You can't put external filters in existing cell phones or GPS units.

A cell phone that can't receive a GPS signal puts the caller at risk during an emergency. They can't be located easily. It takes time to triangulate from cell towers, and that's after they determine which towers are used. I believe the average time is over 5 minutes when they know the towers and up to half an hour when they don't. (Can somebody verify this?) This makes the interference a life-safety issue.

As to what the FCC does about interference, receivers are not protected from interference, transmitters are, so Evert is right on this. The problem with the received signal is that it is a very stable (highly accurate) timing signal which is used by many other systems such as ATMs, cell towers, 2-way radio sites and a whole host of other things requiring highly accurate timing. When LS is broadcasting from their site using both bands, the signals mix and cause harmonics - this is the "interference". The third-order harmonic is the one which causes the most problem. As the harmonic is only present when LS is broadcasting, the GPS people state it is a transmitter problem and not a receiver problem. LS argues the other way, our signals, including the harmonics are within the allowances granted by the FCC.

Everyone confused now?

The LightSquared service uses a frequency that's extremely close to that used by GPS. In addition to possible frequency interference, the LS system is fairly high powered compared to the very low power used for navigation units.

You can bet plenty of GPS users within 300 miles of Boulder (where the test transmitter is installed) will be checking accuracy and reporting issues to the "Las Vegas Sun."

Cheers

So, if it causes GPS receiving blackout, it fails, otherwise, it is successful. hope it is that simple.