GPS Interference Testing

My son is an engineer and is involved in contract work with ratheon out at the nellis test site. He tells me a bunch of the testing is involving ground based station deliberately jamming gps sigs to provide training for fighter aircraft in dealing with airborne gps interference.
As many of you engineer types might know, the gps system utilizes the 1.5ghz band. This high of freq provides for a very narrow bandwidth thus it propogates very well with very low power. However, due to the narrow bandwidth it is very easy to jam the signal.

These notams have been coming out for years, but maybe the testing is finally starting to affect aircraft at a great distance from the source.

Here's an interesting article about GPS testing: https://fas.org/spp/military/program/nav/gpsjam.pdf

I also recall seeing a thread about truck drivers using GPS jammers to thwart being tracked ant these could affect aircraft nearby.

5Z

On Fri, 10 Jun 2016 20:27:51 -0700, tom wrote:

These notams have been coming out for years, but maybe the testing is
finally starting to affect aircraft at a great distance from the source.

Here's an interesting article about GPS testing:
https://fas.org/spp/military/program/nav/gpsjam.pdf

I also recall seeing a thread about truck drivers using GPS jammers to
thwart being tracked ant these could affect aircraft nearby.

5Z

Right, GPS jamming has been going on for years, but it seems to be
getting worse. Yuma Proving Grounds is an Army facility, China Lake is
Navy, Area 51 I suppose is mainly Air Force.

On top of that, the notams are whacky, still showing one for Denver from
the Yuma facility, max radius is listed as 219 nm and yet they're about
700 sm apart. Badly need graphical representations of these things.

-Dave

I received one a couple of weeks ago from aopa that had a graphical map and altitudes indicated that effects well up past Prescott wher I fly mostly.

It must be more than a decade ago than I flew a triangle in western Wisconsin that entered the MOA SE of Eau Claire. The flight log had big drop-outs in the MOA. (This was before OLC.)

Another GPS Interference testing is coming up next week through the end of the month and covers pretty much the whole Great Basin if I interpreted correctly.
I know there have been multiple reports of GPS drops during those testing, but I would like to know if anyone experienced a prolong loss of GPS signal during these testing. I am not overly concerned about the flight log but loss of navigation and some of the flight computer functionality especially when flying long cross country in the Great Basin. Please no comments about using sectional instead. That's my backup plan but I am not in particular fond of it, the same as I am not fond of using pay phones anymore.

Ramy

Hey Ramy, several of us lost gps signal while flying out of Moriarty last week several days in a row when we got high 12 k and, south of Moriarty about 40 miles. It seemed to only effect the older gps units. Mine was a Garmin 196 and others were Cambridge 20 and a puck. My PowerFlarm as well as others were not affected. The outages 2, lasted about 25 minutes or alittle longer one of them seemed to come back as I went north and got lower, the other came back while still high and going east perpendicular to Alamogordo where the testing was aledgedly taking place.

Thanks Cliff. So sounds like it is more of an intermittent issue than a complete black out.

Ramy

On Sunday, July 10, 2016 at 8:45:02 AM UTC-7, Ramy wrote:
Thanks Cliff. So sounds like it is more of an intermittent issue than a complete black out.

Ramy

They usually jam for short periods, perhaps 10 minutes. You might not even notice.
Once saw that WinPilot had a huge wind arrow, indicating something like 140 Knots. Turned out that there was jamming that day and it's how WP reacted to not having info for a while.
Jim

On Sunday, 10 July 2016 09:45:02 UTC-6, Ramy wrote:
Thanks Cliff. So sounds like it is more of an intermittent issue than a complete black out.

Ramy

The NOTAM covers many hours of the day but they will let potentially affected areas know fifteen minutes in advance. For the Great Basin area you can contact Clover Center, the folks that over see the Sevier and Gandy MOA's and Restricted areas with the Utah Test Range on 134.1 to see if they have received any notices or if you are experiencing an outage you can contact them for duration.

The maps and affected areas published are very broad and are more CYA than accurate. During the Nationals at Nephi this year the folks from Clover were able to ensure us that the Great Basin was not likely to be affected from the testing from White Sands and China Lake. The testing done north of Las Vegas and the Utah Test Range are the ones most likely to cover the Great Basin area.

Ron Gleason