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Military GPS hijinks

W

woxofswa

Well Known Member
While flying the trunkliner MDW-TUS tonight, in the area of White Sands, both GPSs were kicking out error messages and terrain mapping quit. ATC openly said that it was due to military operations and they didn't seem too concerned about it, but several aircraft without backups had to go on vectors and a couple were quite concerned. We have IRSs in the Boeing and don't need GPS, but it could be dicey for some. ATC said they usually get a heads up from military but didn't tonight.
 
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How often does it happen?

I would think that is a normal for that area consider what they do there.
Is there usually a NOTAM issued?
 
What happens in the wonderful world of ADS-B during one of these outages? LA Center lists NOTAMS for these outages almost every day, occasionally including a small (0.33 nm) one that covers the final approaches to the south runways at LAX.

And if they de-commission all the radars does ATC go back to steamboats or will we all have to get inertial nav systems?

(Sarcasm mode OFF) I'm just hoping someone in authority has considered the problem. I have asked the question of FAA folks and gotten either a blank stare or been brushed off.

Stan
RV-7A wings
KCCB
Upland, CA
 
GPS Interference Tests

The GPS interference notices and test times are available from FSS and the Coast Guard navcen website. http://www.navcen.uscg.gov/gps/gpsnotices/default.htm

Dan

White Sands Missile Range, NM
(WSMR GPS 07-01)
02 APR 07 ? 03 NOV 07
05 NOV 07 ? 08 MAR 08
10 MAR 07 ? 31 MAR 08
2100-0900Z
2200-1000Z
2100-0900Z
1500-0300L
1500-0300L
1500-0300L
385NM RADIUS OF N33 01 07 W106 17 26 AT FL400, DECREASING IN AREA WITH DECREASE IN ALTITUDE TO 345NM RADIUS AT FL250, 225NM RADIUS AT 10,000FT MSL AND295NM RADIUS AT 4,000FT AGL. THE IMPACT AREA ALSO EXTENDS INTO THE MEXICAN FIR
 
GPS is a DoD run system that has evolved into a "utility" that everyone uses. It is still a DoD system, run by DoD for DoD. The rest of us use it at DoD's pleasure, and they can turn it off at any time. This is why other countries have / are spending a lot of $$ on their own GNSS - they don't want to be subject to DoD's operational restrictions on the system.

GPS is a wonderful system - it increases positional and situational awareness, allows direct routings IFR that save thousands of barrels of fuel daily and saves lots of lives. But, it is a military system, so don't be surprised when the military turns it off or degrades it.

Remember that SA (selective availability) was turned off in 2000, but DoD says that they now have other means to degrade or deny GPS signals to anyone, anywhere, anytime.

So, this points out the value of the lowly, old, low-tech VOR - the FAA runs them. I'm not sure if this is good or bad, but it's unlikely that the FAA will decide to turn them off at any time, at least not on purpose. There have been other threads about equipping an airplane for IFR with GPS only; hopefully this points out that it's not a great idea.

And yes, what does that mean for ADS-B? Since the FAA has committed to basing everything off ADS-B, which is itself based on a GPS signal, the entire air traffic system will be dependent on good GPS signals. Indeed, this needs some more consideration.

TODR
 
That costs extra...

splevy said:
What happens in the wonderful world of ADS-B during one of these outages? LA Center lists NOTAMS for these outages almost every day, occasionally including a small (0.33 nm) one that covers the final approaches to the south runways at LAX.

And if they de-commission all the radars does ATC go back to steamboats or will we all have to get inertial nav systems?

(Sarcasm mode OFF) I'm just hoping someone in authority has considered the problem. I have asked the question of FAA folks and gotten either a blank stare or been brushed off.

Stan
RV-7A wings
KCCB
Upland, CA
Click to expand...


"Oh, you want ADS-B to work ALL of the time? Well, that's going to cost a little extra. We hadn't included that in our financial calculations. Hmm, let's see(clackity-clackity of adding machine)... that will cost somewhere between 10% and 3000% more than the initial estimate."

Perhaps we can fund it by increasing the fuel tax on those folks who rarely or never use ATC.:eek:
 
ADS-B

Good points and I am vehemently opposed to the ADS-B Out NPRM.

My (still in work) response to that NPRM is here:

http://tinyurl.com/2wem8j

It may be costly with minimal to no benefit to most GA pilots. The FAA needs MORE primary radars...not less.
 
Galileo is no panacea

It probably would also be affected by such activities. Do note that these events are NOTAMed so it is not correct to blame the DoD. I doubt that the DoD will ever "turn off" GPS.

Plus there is no guarantee that Galileo will ever be built. From the beginning, it has suffered from an unrealistic cost-benefit argument.
 
Last year I was flying adjacent to a "hot" restricted area according to ATC. My GPS went out so I turned on my VORs. They were both off by at least 60degrees and it took me some time to figure out what the problem was. I was fairly familiar with area and continued to my desstination using old fashioned pilotage. I was wondering if I was being watched to see how I would react. It would certianly be a good way to throw off 9-11 hijackers who were searching for a target. I am gald they have that capability.
 
You youngsters are all spoiled - no piece of equipment can or should take the place of pilotage, situational awareness, or preparedness to navigate partial panel.

Reminds me of the cold war days in Germany. Flying at night, suddenly a controller whose voice you recognized from years of training flights would say, "Mako flight, vector 090 for separation." Of course, if you weren't paying attention to the fact that you were on the East German border you would just follow the instructions and be the focus of an international incident - not to mention getting your arse chewed for being an idiot.

Bottom line - know your systems and your flight plan and have a backup plan.

Oh, and stop whining that the folks who keep you safe run exercises to keep our boys prepared for anything!
 
Ron, Ron...

Ron,

I'm a radar engineer, you'd think I'd be in favor of more radars, but the fact is gps can provide 10-100x more accurate positioning and at a significantly reduced cost to the government (I should say reduced cost to the FAA, the gps constellation is VERY expensive, but it is free as far as FAA is concerned). This accuracy clearly equates to improved collision avoidance safety and the Capstone project provided solid evidence. I'm sorry, but your arguments fall short. I'm not in favor of any govt mandate, but the technology/cost decision to transition to ADS-B is very difficult to argue against.

You can argue that we will likely be burdened with the cost of the new transponders and yes GDL 90's are $7k today, but if you want to hold out until the mandate in 2020 they will be less than mode C transponders today. They should be cheaper, there is nothing more than the technology in a cell phone. Moreover you'll see all the EFIS manufactures incorporate the ADS-B In functionality currently supported by Chelton and Garmin. And why will aviators want it? Because it will provide by far the best possible traffic awareness and real time weather and at a very low cost.

Yes gps is easy to jam, but so is radar (and VORs). How long to you think the western ranges will be allowed to test open jamming when an airliner dependent upon gps navigation and situational awareness is found crashed because of a DoD test? Didn't they use to test atomic bombs out there a few years back? Wonder why they stopped (at least above ground)?

ajay


Ron Lee said:
Good points and I am vehemently opposed to the ADS-B Out NPRM.

My (still in work) response to that NPRM is here:

http://tinyurl.com/2wem8j

It may be costly with minimal to no benefit to most GA pilots. The FAA needs MORE primary radars...not less.
Click to expand...
 
ajay said:
Ron,

I'm a radar engineer,
Click to expand...
Preaching to the choir. But I believe a secondary means of navigation is just smart thinking. Pilotage isn't an option to the IFR pilot as a backup.

Yes gps is easy to jam, but so is radar (and VORs). How long to you think the western ranges will be allowed to test open jamming when an airliner dependent upon gps navigation and situational awareness is found crashed because of a DoD test? Didn't they use to test atomic bombs out there a few years back? Wonder why they stopped (at least above ground)?
ajay
Click to expand...

The GPS tests are usually NOTAM'd and as was pointed out, very large radius.

GPS has its share of issues, but the worst is yet to come. The predictions are that during the peak of the sunspot cycle in a few years will make GPS useless. What exactly will happen? We don't know as we didn't have such widespread use of GPS during the last cycle peak. They are, however, planning to add additional frequencies for civilian use and atmospheric correction, so perhaps there will be at least one usable channel during atmospheric events.

And for the record, there was only one nuke explosion at WSMR... the first. ;)
 
Ajay, read the NPRM and my response

If you do both and you are objective most likely you will agree with me.

I do not need 10x better position accuracy for flight following collision avoidance. It is not needed.

Capstone (Southeast Alaska) cannot be translated to the lower 48 in terms of safety improvement. Just can't.

The ADS-B Out NPRM offers little to no benefit to most GA pilots. Read the available documentation. You can't show a viable benefit to me. It is not there.

I do know that replacing primary radars with secondary (SSR) radars will reduce safety. I saw that on a recent trip from back east.

Your assertion that the ADS-B Out equipmennt will be less than transponders has zero credibility. Plus you will still need Mode C transponder functionality as backup.
 
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Benefit is ADS-B In not Out

Ron,

You tell me, which you would rather have

1. a ground based radar picture that can have errors of 100-1000 meters with the added delay of a controller telling you what sector the traffic is headed/coming - adding miles of more error and add to that the time delay error of reporting.

or

2. an accurate real time depiction of surrounding traffic on your moving map precise to 10s of meters

Do you really believe this accuracy (2) doesn't equate to improved safety? This has much more potential benefit in congested areas like the east coast than Alaska.

The requirement is only for ADS-B out, but the faa is smart enough to realize that aviators are going to want the benefit and get ADS-B in functionality.

Mode C will only be required during the transition period, the ADS-B message will incorporate your unique id and N #, ADS-B is a transponder too, there will be no need to have both. Unfortunately Big Brother will know exactly who and where you are, I'm not too happy about that.

The bad news is it is only a matter of time before Big Brother is going to require them in our cars and shortly after that an implant in our bodies. So if your smoke screen argument is for libertarian reasons I'm with you, but unfortunately the science is on there side on this one.

ajay

Ron Lee said:
If you do both and you are objective most likely you will agree with me.

I do not need 10x better position accuracy for flight following collision avoidance. It is not needed.

Capstone (Southeast Alaska) cannot be translated to the lower 48 in terms of safety improvement. Just can't.

The ADS-B Out NPRM offers little to no benefit to most GA pilots. Read the available documentation. You can't show a viable benefit to me. It is not there.

I do know that replacing primary radars with secondary (SSR) radars will reduce safety. I saw that on a recent trip from back east.

Your assertion that the ADS-B Out equipmennt will be less than transponders has zero credibility. Plus you will still need Mode C transponder functionality as backup.
Click to expand...
 
1000M is good enough for me

Thread drift...

I'd think homeland defense would be reason enough to keep primary radars. I also like it when approach points out targets without transponders. Cubs, crop dusters, and large flocks of birds show up on primary radar.

10M accuracy? Who needs that type of accuracy for traffic avoidance? Now if you're an airliner doing an ILS on 17C with someone else doing simultaneous approaches on 17L and 17R at a large hub, maybe. That doesn't mean that we need to equip the whole fleet. ADS-B would also be great for remote or oceanic areas but we already have a system for that called TCAS.

Another thing to consider is failure modes (besides the GPS constellation). What happens when your ADS-B box fails? At least we have a few layers of redundancy now (Primary radar, SSR, overlapping coverage)

Paige
 
Paige,

I like your arguments and kind of agree with you.

The counter argument, however, is the primary radars, SSRs, and controllers are expensive to maintain. The faa is viewing this as an increased capability for less money, pretty good business case.

ajay

PaigeHoffart said:
Thread drift...

I'd think homeland defense would be reason enough to keep primary radars. I also like it when approach points out targets without transponders. Cubs, crop dusters, and large flocks of birds show up on primary radar.

10M accuracy? Who needs that type of accuracy for traffic avoidance? Now if you're an airliner doing an ILS on 17C with someone else doing simultaneous approaches on 17L and 17R at a large hub, maybe. That doesn't mean that we need to equip the whole fleet. ADS-B would also be great for remote or oceanic areas but we already have a system for that called TCAS.

Another thing to consider is failure modes (besides the GPS constellation). What happens when your ADS-B box fails? At least we have a few layers of redundancy now (Primary radar, SSR, overlapping coverage)

Paige
Click to expand...
 
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