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#11
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GPS Interference Testing
On Friday, June 10, 2016 at 8:23:46 AM UTC-7, Dan Marotta wrote:
I suspect it's from ground based emitters. A hand held device, perhaps the size of an Icom A22? Cheeky *******s. Jim |
#12
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GPS Interference Testing
No, was north of Denver which is farther away from Alamagordo.
Current GPS domestic notams should be visible he http://tinyurl.com/prds7nr They list two sets of coordinates, neither of which match the China Lake coordinates which were listed in the original advisory note (which is still on the web, btw). So maybe the original China Lake testing has been canceled, replaced by similar testing in other locations? All the information I've seen indicates a ground-based emitter, with an upside-down wedding cake area of interference. Maybe the old 302 is starting to kick the bucket, seems like an unusual failure mode though. -Dave On Fri, 10 Jun 2016 09:23:40 -0600, Dan Marotta wrote: Hi Dave, Were you within 300 nm of Alamogordo? I haven't checked the notams, but you could have gotten zinged by some of the continuous testing which seems to go on there. BTW, do you know where the jamming is coming from? If it's from orbit, being low in CO wouldn't matter too much, but I suspect it's from ground based emitters. On 6/10/2016 8:39 AM, David Kinsell wrote: You should be loading up on lotto tickets, Dan. Interestingly, I had a decent flight yesterday, everything seemed to be working fine. Up until just before the landing pattern, when GPS altitude indication started flipping between correct altitude, and 0. It was just a couple minutes around 23:19 zulu, 5:19 pm local. IGC file uploaded to OLC, no problem, you can pull it from region 9 US. Got the two green dots from OLC, plane didn't start doing Dutch rolls or anything, but it does seem strange that my trusty 302 would choose June 9 to start acting up. Viewing the file on SeeYou shows what I was seeing in the cockpit. Down low in Colorado, wouldn't have thought the canceled China Lake testing (whose notams never seem to go away) could be involved here, but who knows? -Dave On Wed, 08 Jun 2016 20:06:23 -0600, Dan Marotta wrote: I flew my Stemme from Minden to Moriarty yesterday (after a week of soaring!) and had GPS coverage for the entire trip. Guess I got lucky... On 6/7/2016 8:13 AM, Eric Bick (ZN7) wrote: Everyone out west seen this NOTAM re GPS interference testing. Covers most of the western US - NoCal and SoCal soaring sites, OR, Nephi, Parowan, other - and continues throughout June on selected dates. https://www.faasafety.gov/files/notices/2016/Jun/ CHLK_16-08_GPS_Flight_Advisory.pdf |
#13
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GPS Interference Testing
Wild hypothetical, what if GPS gaming is going on durning a contest and some or all contestants lose part of the logging of points on course? Years ago I was denied a Diamond distance/goal because of about four minutes where the Cambridge logger didn't log. I returned and flew that segment of the flight but was still denied. It was obvious that I could not have landed and taken off again.
Also, does the GPS jamming affect 406 ELT's? What about planes on IFR plans solely using GPS for navigation? |
#14
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GPS Interference Testing
On Friday, June 10, 2016 at 10:01:15 AM UTC-7, Jonathan St. Cloud wrote:
Wild hypothetical, what if GPS gaming is going on durning a contest and some or all contestants lose part of the logging of points on course? Years ago I was denied a Diamond distance/goal because of about four minutes where the Cambridge logger didn't log. I returned and flew that segment of the flight but was still denied. It was obvious that I could not have landed and taken off again. Also, does the GPS jamming affect 406 ELT's? What about planes on IFR plans solely using GPS for navigation? 406MHz ELTs with GPS... sure possibly. But all 406MHz ELTs are also capable of SARSAT/COSPAS doppler location and have 121.5 MHz homing beacon. Practical impacts on air navigation are a much higher level concern. |
#15
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GPS Interference Testing
On Fri, 10 Jun 2016 10:01:13 -0700, Jonathan St. Cloud wrote:
Wild hypothetical, what if GPS gaming is going on durning a contest and some or all contestants lose part of the logging of points on course? Years ago I was denied a Diamond distance/goal because of about four minutes where the Cambridge logger didn't log. I returned and flew that segment of the flight but was still denied. It was obvious that I could not have landed and taken off again. Also, does the GPS jamming affect 406 ELT's? What about planes on IFR plans solely using GPS for navigation? You know that Embraer jet they keep mentioning in the notams? Apparently a real problem: http://www.faa.gov/documentLibrary/m...11_EMB-300.pdf Who would have thought loss of GPS would cause flight control problems? Losing points in some glider competition is way down on the list when it comes to things to worry about. How about when the whole air traffic control system becomes reliant on ADS-B and GPS gets jammed, either by the military or maybe even some bad guys? |
#16
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GPS Interference Testing
The DOD has been doing this for awhile now. I flew through central Nevada near Wilson Creek a few weeks ago and it shut both of my GPS units down. We were on an IFR flight plan in touch with ATC and you wouldn't believe the ruckus it was creating. There were quite a few very concerned pilots. We just asked for vectors and got it, no big deal. Eventually we left the zone and our gps started working again. My first thought was that there was something wrong with the plane.
Personally, I think the DOD is listening in on ATC frequencies and we are part of the experiment to determine the range of some new kind of jamming device. |
#17
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GPS Interference Testing
I was N of Denver CO, which has had notams listing two centers of
activity. One appears to be Area 51, the other one Yuma Proving Grounds. Those are so far S I can't believe they were involved, I was just a couple thousand feet AGL when the issue popped up. But I'll be a whole lot closer to '51 next week. -Dave On Fri, 10 Jun 2016 09:23:40 -0600, Dan Marotta wrote: Hi Dave, Were you within 300 nm of Alamogordo? I haven't checked the notams, but you could have gotten zinged by some of the continuous testing which seems to go on there. BTW, do you know where the jamming is coming from? If it's from orbit, being low in CO wouldn't matter too much, but I suspect it's from ground based emitters. On 6/10/2016 8:39 AM, David Kinsell wrote: You should be loading up on lotto tickets, Dan. Interestingly, I had a decent flight yesterday, everything seemed to be working fine. Up until just before the landing pattern, when GPS altitude indication started flipping between correct altitude, and 0. It was just a couple minutes around 23:19 zulu, 5:19 pm local. IGC file uploaded to OLC, no problem, you can pull it from region 9 US. Got the two green dots from OLC, plane didn't start doing Dutch rolls or anything, but it does seem strange that my trusty 302 would choose June 9 to start acting up. Viewing the file on SeeYou shows what I was seeing in the cockpit. Down low in Colorado, wouldn't have thought the canceled China Lake testing (whose notams never seem to go away) could be involved here, but who knows? -Dave On Wed, 08 Jun 2016 20:06:23 -0600, Dan Marotta wrote: I flew my Stemme from Minden to Moriarty yesterday (after a week of soaring!) and had GPS coverage for the entire trip. Guess I got lucky... On 6/7/2016 8:13 AM, Eric Bick (ZN7) wrote: Everyone out west seen this NOTAM re GPS interference testing. Covers most of the western US - NoCal and SoCal soaring sites, OR, Nephi, Parowan, other - and continues throughout June on selected dates. https://www.faasafety.gov/files/notices/2016/Jun/ CHLK_16-08_GPS_Flight_Advisory.pdf |
#18
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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. |
#19
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GPS Interference Testing
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 |
#20
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GPS Interference Testing
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 |
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