NTC Fort Irwin GPS Interference Testing

[bryan_herbert]

 

[Eng74]

Interesting, I might have to pull up my GPS on my truck if I am driving around town see if anything happens.

 

[alcahuete]

This happens on almost a daily basis out here in California and Nevada.

 

[zz0468]

This happens on almost a daily basis out here in California and Nevada.

I frequently see NOTAMS out about GPS disturbances due to military activity. Most seem to center around China Lake, but I've seen plenty out of the Nellis Range, and much less frequently, Ft. Irwin.

Some of them even seem to affect GPS timing systems that are used to provide frequency references for telecom equipment. Back when LORAN was still running, it was possible to measure the GPS degradation. LORAN was referenced to clocks at the US Naval Observatory, and GPS is referenced from an ensemble that includes NIST. They were always very very close, but not identical. I've seen GPS events such as this degrade timing by several orders of magnitude, i.e. from 10E-13 to 10E-10.

 

[zz0468]

Interesting, I might have to pull up my GPS on my truck if I am driving around town see if anything happens.

I doubt you'd notice. Automotive GPS uses techniques to keep the vehicle icon on the established roads, in spite of significant errors in actual measured position. I first observed it when traveling on a new stretch of freeway about 10 years or so ago. As I traveled on the new stretch of freeway, the old highway gradually veered off to the south, and the GPS showed me staying on the old road until it was almost a half mile away. It then jumped me to the next closest piece of road it had in it's map database, and kept behaving that way until I was back on an older stretch of highway.

A GPS puck plugged directly into a laptop running a topographic map program will wander around and leave an interesting trail in a parked vehicle, but the automotive GPS holds it's position on the nearest mapped road.

 

[mmckenna]

Interesting, I might have to pull up my GPS on my truck if I am driving around town see if anything happens.

You might be able to use the ADS-B websites, like Flight Radar 24, to see it. There's a lot of traffic that goes around that area that would certainly be in range of that.

 

[alcahuete]

I frequently see NOTAMS out about GPS disturbances due to military activity. Most seem to center around China Lake, but I've seen plenty out of the Nellis Range, and much less frequently, Ft. Irwin.

Yep, those are the general hotspots. Yuma, White Sands, are other common locations. Ft. Irwin usually does other types of testing, with the occassional GPS jamming. Based on the map, this is a very low power or focused test.