Car has a built-in GPS signal jammer?

[+ivss_xx]

Has anyone ever heard of cars that deliberately interfere with GPS signals?

 

So, my friend has a Toyota Wish (2003 or 2005 make). Whenever we go geocaching with it, my Garmin Oregon 300 is rendered quite useless while the car is running. What happens is, the GPS accuracy shown in the device stays the same, it still shows 5m/6m/7m, the usual but the GPS arrow just drifts away somewhere. In reality, the accuracy is now about +/-100 up until 300 meters. It just goes somewhere in a random direction.

When I get out of the car, if I want to get the location right, I have to restart my unit. If I do not restart it, it sorts itself out eventually but that takes some time, maybe 5 minutes or so. I can go back to the car, sit in it and everything is fine but as soon as we start driving, the GPS arrow drifts away again.

 

So, the car has a built-in navigation, my guess is that maybe manufacturers have installed some sort of jammer that would interfere with GPS signals of the receivers in the car, and only their device has the decoder that gets the signal right after the jamming. That way you would be bound to use GPS from them and fix it by them, them making money out of it. But that sounds like really douchebag thing to do to your clients...

 

Anyone ever experienced something like this?

[+kunarion]

I haven't had any issues. Does the car have Bluetooth or wifi? Something that produces interference might cause problems, not necesarily a factory-installed GPS Jammer.

 

Here's a thread with a similar theme:

http://forums.Groundspeak.com/GC/index.php?showtopic=73121

Edited May 2, 2016 by kunarion

[+on4bam]

my guess is that maybe manufacturers have installed some sort of jammer that would interfere with GPS signals of the receivers in the car, and only their device has the decoder that gets the signal right after the jamming. That way you would be bound to use GPS from them and fix it by them, them making money out of it. But that sounds like really douchebag thing to do to your clients...

 

Nice conspiracytheory.

Does the car have coated windows by any chance? Some manufacturers use a special coating on glass to filter UV and/or sunlight. This coating contains metal and can make reception of radio signals difficult. The higher the frequency the more signals are weakened. Try to roll down the window and see if that fixes things.

For it's own GPS the car probably has an external antenna tucked away in a place that's not shielded.

[+ivss_xx]

Nice conspiracytheory.

 

Yes, I' m proud of myself that I could come up with my own conspiracy here

 

Well, the windows on backseat doors are coated, not the windscreen and front side windows, I think.

But when the car is not running, it is just fine, with the windows up.

But why does the GPS unit not know that the accuracy is 300 instead of 3m? Shouldn't the accuracy then change accordingly? E.g. if I'm walking between high buildings, the arrow drifts away but then the accuracy meter shows 28m or whatever it thinks it's wrong.

[+cerberus1]

Back when the Dead Sea was just sick, my blue legend wouldn't work at all if too close to the blackberry on my belt.

- The conspiracy theorist in me thinks that "they" were up to something (yes, even) that long ago...

[+digimuzik]

Pretty sure GPS jammers (along with cell phone jammers) are quite illegal (think of the risks to emergency responders). Maybe there are just too many electronics being activated when the car is on.

 

That sucks, though. At least it's not your car. If it was yours, I'd say a new car was definitely in order. Nothing wrong with replacing your wheels for the game.

[+larryc43230]

I've used three different Garmin handheld GPS units over the years, and they've all reacted the same way inside a car.

 

Let's say I've set the GPS to point to a particular geocache (and I'm using direct navigation, not turn-by-turn). The "GPS Accuracy" displayed on the unit isn't affected by the car (if it reads 20 feet inside, it will read about the same outside). However, if the compass screen is displayed I can never trust the direction the compass arrow is pointing. The arrow might be pointing far to the left inside the car, and suddenly swivel 180 degrees when I get out of the car. I'm guessing that all the metal in the vehicle can interfere with the compass reading.

 

--Larry

[+Jake81499]

No problems here, only thing I've seen is when getting out of the car or off the bike the gps locks up if it's in map mode and sometimes the dashboard mode. And that happens with every gps I've owned.

Edited May 3, 2016 by Jake81499

[+Red90]

Usually is is because of heated windshields.

[+kunarion]

The arrow might be pointing far to the left inside the car, and suddenly swivel 180 degrees when I get out of the car. I'm guessing that all the metal in the vehicle can interfere with the compass reading.

 

I've seen that effect in my car (Not lately. New car. ). It didn't matter if the car was running or not. Calibration issue, I guess. Yeah, metal in the car. But many GPSrs automatically switch to GPS compass once the car is moving. There's a setting for that.

 

It seemed to me that the OP's problem is something other than just a compass calibration thing.

Edited May 3, 2016 by kunarion

[+GrateBear]

I've used 3 different Garmins (handhelds), and when in the car, while moving they do just fine. As soon as I stop, though, the screen shifts around and no longer "points" in the direction I'm heading. Don't know why, but I can live with it.

[+ivss_xx]

Oh, I'm not talking about the arrow pointing in the wrong direction. I'm not using the compass at all, it is turned off in my unit. I mean that the arrow is not at the location where the unit is, it is shifted for up to 300m to somewhere else, but GPS still shows that the accuracy is 6m or whatever small number.

You arrive at GZ, step out of the car, restart the GPS and then realize that GZ is actually 300m away

[+Red90]

Oh, I see Oregon 300. They had a weird problem of wondering off in poor reception conditions and requiring a reboot. It never did get completely solved with firmware upgrades. IIRC, it only happens when WAAS is on. Make sure you have the newest firmware and GPS firmware as it did improve with software revisions.

[+BlackRose67]

Keep in mind that you are travelling in a big metal can with lots of electrical wiring.

 

My Oregon 600 (and previously GPSMAP 62s and eTrex 20) all give less than accurate results when used inside the car.

 

As soon as we step outside, they work as expected.

[+Red90]

As soon as we step outside, they work as expected.

 

Trust me. This is NOT that problem. The first generation Oregons and Colorados developed this problem after a certain GPS firmware update and it was never fixed. In certain poor reception conditions, they will start to wander way off and will NEVER come back until rebooted. I seem to recall it would not happen if WAAS was off, but I'm not sure. It got better with later firmware, but never entirely disappeared.

[+MtnMutt-ProDuckShins]

This vehicle has a huge windshield which should allow clear view of sky. Are you putting the GPSr on the dash or possibly in your hands in say the backseat?

 

You didn't mention where the unit placement is, the dash would be your best bet.

[+The A-Team]

I'd put my money on those saying it's a software bug. If it were really a reception problem (caused by metal, electromagnetic interference, heated/coated glass, etc.), the EPE (the "accuracy" number) shown on the device would go way up like if you were trying to use it indoors. The fact that it claims to have decent reception but still wanders off just screams "software issue", especially considering this seems to be a known issue with that model of device.

[39_Steps]

It does sound like a software bug, particularly if the Garmin 300 has a "Snap-to-Route" feature. (Like the Nuvis.) I would check to see if there is a snap-to feature that can be disabled to better understand drift characteristics of the device in canyons or trees. Is it real or is it Memorex? Is it a drift or a shift?