4G Broadband interferes with GPS? Garmin says yes.

[Captain X]

Some big names in the GPS industry – such as Garmin and Trimble got together with U.S. GPS Industry Council got together and published a study to warn FCC that the proposed 4G network by LightSquared would jam everyday GPS devices such as Garmin 265W and even FAA certified GNS 430W (general aviation receiver) from literally miles and miles away.

The heart of the problem is that LightSquared intends to use L Band 1 (1525 MHz—1559 MHz), which is right next to where the GPS frequencies of 1559—1610 MHz. If the proposal by LightSquared goes through they’d be covering the nation with with 40,000 transmitters which would turn vast areas of U.S. into a big dead zone for GPS receivers.

Lightsquared plans to wholesale LTE network while competing with ClearWire. With their proposed 40,000 cellular base stations they plan on covering 92% of the U.S. by 2015.

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more info here http://www.gpsworld.com/gnss-system/new ... ster-11029

[2.5milefinal]

Thats really not good.

[Liquid Charlie]

Well they will need to make their gps receivers 4g compliant and then charge for the navigation service using the cell network to pinpoint your position. Simple economics -- it's all about getting up the ass anyway --

[skat0r]

stupid smartphones

[Captain X]

Old topic brought back.

Has anyone had similar experiences?

In the YXD area approaching runway 12 we will get integ error (lose all navigation) on our garmin 400. It usually lasts for 5-30 seconds.

It usually occurs near the CFB Namao. I wonder if they have some sort of radio antenna thats jamming up our gps signal, or just happens to be a 4g cell tower nearby.

[Liquid Charlie]

First -- is it just your unit or are others affected as well - the hspa+ and even LTE when it appears will operate on the same frequencies - 850 and 1900 mhz mainly with fringe operators such as Wind on 1700 and 2100 mhz -- without going back I believe some of the concern was the expanded frequencies that might be offered in the future to mobile carriers --

I would suspect your issues are either to do with your unit, geographical -- is this a aircraft mounted unit or a dash mount with internal antenna -- are there any NOTAMS covering this --

[Bushav8er]

WHY do we need 40,000 GROUND based transmitters? The scenery on the ground would be a lot nicer if cell companies, like everyone else, switched to satellite based communications. More expense phone bills? I think not (at least no reason to be), my satellite tv bill is less than my cell phone already.

This too comes down to supply & demand though...everyone wants more, more, more and faster, faster...they are just filling that want (none of this hi-tech crap is a need).

[SAR_YQQ]

my satellite tv bill is less than my cell phone already.

Apples and oranges - google satellite internet and that would give you a better idea of what two way sat-com costs. Sat TV is only one way.

[Rockie]

Lightsquared is working on a technical solution to eliminate interference with GPS signals, but if they cannot find an airtight solution the FCC will obviously not allow them to proceed with their plans. The US will do what it takes to protect the integrity of the GPS system.

[The Hammer]

Sat phones suck ass most of the time but are excellent tools in remote areas for less frequent communication, not like a cell phone (when they work, we see geographic areas that communication is always tough and solar activity is a problem too.)

In the late 90's ?? the "Iridium" satt. network was supposed to revolutionize the portable phone network and kill cell phones because it worked worldwide. They launched lots of sattelites (and $) and it never came to what they had predicted. Some how they they either overlooked the fact that it doesn't work in a building or expected people to go outside to use it ie "Can you hear me now???". Their prime target was international travellers ie CEO's, Were they going to leave the boardroom, get in the elevator, walk out on the street, and make /take a call.

Until all those issues plus the "delay factor" (which makes discussion nearly impossible, we use "over" a lot) are removed satt. is not an obsession.

IMHO

[Captain X]

It's a approved installation, certified for IFR flight. We only have one gps in the machine. The reason for asking is to see if anyone else has had any similar problems in the YXD area or anywhere else for that matter.

[120@8']

Had the same thing happen 2 nights ago going into YXD on the LPV - RNAV 12 as well. 530W & 430W both momentarily lost all signal. 530W came back just downgraded to LNAV and the 430W went to Enroute. Talked to another pilot who flew in earlier that night and said they lost INTEG momentarily with their 430.

[Captain X]

I wonder if any agencies (navcanada or TC) that investigates these issues.

[loopy]

I've noticed a couple of glitches going into CYXD as well. I guess next time I'll dig out that TC GPS reporting form and use it.

[ogopogo]

Lightsquared was given a licence by the FCC to install their 40,000 towers (which repeat their satellite signal -- it's called Ancillary Terrestrial Component) on the condition that they cause no harm to the GPS community.

Turns out there is big time harm.

But the problem is not the Lightsquared transmitters -- they are clean; the problem is with the original designs of the GPS receivers.... they are not frequency selective enough. They were designed back in the day, and no one anticipated there could one day be nearby transmitters which 'desensitize' GPS receivers.

The argument bewteen the two parties is ongoing, but Lightsquared's contention is that they haven't done anything wrong. In fact they have proposed to drastically reduce their transmit power, and have also stated they will use their lower band (initially) which is a little further away from the GPS L1 freq.

Still a huge mess, though.

[cgzro]

WHY do we need 40,000 GROUND based transmitters?

The more transmitters you use, the lower the power, lower the delay and highter the throughput is.

For example, one big transmitter (like a sattelite) talking to 10 million smart phones is going to need some kick ass bandwidth to give everybody decent service and you are gonna need a big battery. However if you divide it up into 1000's of transmitters talking to 1000's of smart phones you get waaaaay more throughput each, there is less power required and less interference etc. We are heading towards pico cells, so the power will be even lower. Infact your cell phone/smart phone adjusts its power on the fly as necessary to use just enough oomph to get to a tower. The 4G stuff will soon be able to 'aim' its transmission toward you, rather than just broadcast it so that will improve things yet again.

I wonder if any agencies (navcanada or TC) that investigates these issues.

I believe the gov't checks all the ILS and I presume GPS approaches periodically. I think they have some pimped up jet bristling with antennas that measures the accuracy etc.

Well they will need to make their gps receivers 4g compliant and then charge for the navigation service using the cell network to pinpoint your position.

Actually the iPhones already do that. They know the lat/long of most cell towers and then can triangulate. its pretty impressive and it would make sense for GPS to include as many sources as possible including cell towers of course its not as accurate but I can't hurt to have redundant sources.

[oleo]

Alright, time to dust off the charts lol

[cgzro]

Alright, time to dust off the charts lol

I imagine that if it is GPS that is at fault, the FCC will simply buy back the spectrum on both sides of the GPS band to provide some protection (guard bands).

Lightsquared probably bought that spectrum at auction for god knows how many billions of dollars and expected to be able to use all of it.

The FCC could I suppose recoup some of the lost revenu by taxing GPS units or something.

I just can't see (in the US/Canada/Europe) GPS being allowed to get clobbered but what other countries do with their spectrum is their buisness of course.

It does make sense in the future however for GPS receivers to also triangulate on Cell towers as an additional check.

By the way, just for fun .. the cell base stations, many of them, rely on GPS signals for their time syncrhonization so it may be the case that if they interfere with the GPS signal they won't be able to recover the time syncrhonization signals that they need to operate.

The cell base stations need extremely precise time syncrhonization for hand-off, to stay on frequency etc. and the cheapest way to get it is free from the GPS satellites .. otherwise they need expensive high precision timing sources like Atomic Clocks etc.

[corytrevor]

"My GPS is screwed"

"there's an app for that"

[yousuckmonday]

In the States AOPA have been pursuing this matter for a while.

Some websites would lead you to believe that LightSquared made sizeable donations to the Democratic party during Obama's campaign and that LightSquared is pretty much a done deal, GPS manufacturers are just going to have to nut up. But that is the internet conspiracy theorists at work... light on details, quick and loose with facts, great stories.