6 ms·

Funny enough, if GPS does get jammed, the USAF has a whole lot of equipment that would be almost useless... Like every modern airplane they own.

by kpeel 16y ago

mkr-hn 16y ago
We need someone with air force experience in here. It doesn't seem like they'd let them fly without knowing alternate ways of navigating.
- oigftrgtyh 16y ago
  Descend until you can see the freeway and follow that is always popular!
  - mkr-hn 16y ago
    It's obvious now that I think about it. Even with GPS, they're going to be told landmarks and indicators (roads and stuff) during a briefing.
    - aj700 16y ago
      Why shouldn't this break military plane GPS as much as anything else. It will also remove the ability of USAF to GPS target missiles onto US population centres, which they have no need to do anyway. They can still bomb the rest of the world no problem.
      - Kadin 16y ago
        Military GPS receivers operate on two carrier frequencies, only one of which is used by most civilian models. (And it's the shared military/civilian frequency which is adjacent to the spectrum in question.) Using two frequencies makes the military receivers more robust, and also lets them do some clever ionospheric distortion cancellation that you can't do with one channel. (Basically they get the benefits of WAAS without actually needing to receive the WAAS signal.) That said, neither the FAA or the military are going to tolerate any significant degradation of GPS, domestically or otherwise.
- kpeel 16y ago
  Yeah, I was joking a little. Most aircraft would still work pretty well off of inertial data. However there are quite a few weapons systems that just plain won't work without GPS. BTW, I'm not a pilot, but I work for a government aerospace contractor, so I have some experience in this.
  - mkr-hn 16y ago
    I figured GPS-guided bombs would be the only thing impacted. Cruise missiles match terrain to what's stored in memory to know where to drop.
  - icegreentea 16y ago
    I thought the most common ones (JDAMs) still had an inertial navigation system cause GPS/INS is used nearly everywhere. It'll probably have horrible accuracy (I guess that depends on how the coordinates sent to the bomb are handled... if it can be calculated as an offset of what the INS thinks it is, then it wouldn't be that bad). But still better then unguided bombs.
- winthrowe 16y ago
  I'm not actually air force, but am a bit of an aviation buff with a private license. There would be backup nav systems in manned aircraft, but several popular modern munitions are GPS guided, and I would tend to think that modern battlespace information systems require it as well. Planes wouldn't fall out of the sky, but it would be a significant departure from the ideal state.
  - mkr-hn 16y ago
    If you have time, I wouldn't mind some examples. I'm curious, not doubtful. Since this thread sprung up I've wondered what might be impacted by a GPS failure.
    - winthrowe 16y ago
      Of the munitions? I hear JSOWs and especially JDAMs are popular recently. As far as BIS info, it's not something I've followed closely, but we're talking things like every plane, tank, and infantryman now (soon?) has gps and information on the location of all friendly forces is automatically shared so you cut down friendly fire. Apparently caf has more info on milspec GPS than I do, I thought that it required the same main band as civilian, and just used additional military bands to increase precision, but apparently it can function fully independently (not really surprising when you think about it). At least that gives you a little info on some of the troubles of failure of military GPS, as unlikely as that is. http://en.wikipedia.org/wiki/Joint_Stand-Off_Weapon http://en.wikipedia.org/wiki/Joint_Stand-Off_Weapon http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition
- caf 16y ago
  US Military GPS has access to a separate P(Y) signal on the L2 frequency that civilian GPS does not.
- philwelch 16y ago
  Depending on the plane, there are cases where a full systems failure knocks out every means of navigation other than "Mark I Eyeball": http://www.defenseindustrydaily.com/f22-squadron-shot-down-by-the-international-date-line-03087/ http://www.defenseindustrydaily.com/f22-squadron-shot-down-b...
oomkiller 16y ago
Actually most modern munitions are guided by inertial navigation, mainly so targets can't jam them. Aircraft etc also have this capability. They have known about the risk of jamming since the beginning, so surely they've prepared for it.
- kpeel 16y ago
  Very true. My answer was a bit tounge-in-cheek, I just didn't get it across properly. While losing GPS would be a problem, it certainly wouldn't bring down our military. This specific problem definitely wouldn't affect our aircraft simply because they would be at such a high altitude. Even if it was a problem, the military also has a some pretty impressive anti-jamming capability.
smallblacksun 16y ago
Conveniently, the USAF also has a lot of anti-radiation missiles that are very good at eliminating jamming sources.

Funny enough, if GPS does get jammed, the USAF has a whole lot of equipment that would be almost useless... Like every modern airplane they own.

by kpeel 16y ago

Funny enough, if GPS does get jammed, the USAF has a whole lot of equipment that would be almost useless... Like every modern airplane they own.

mkr-hn 16y ago

We need someone with air force experience in here. It doesn't seem like they'd let them fly without knowing alternate ways of navigating.

oigftrgtyh 16y ago
Descend until you can see the freeway and follow that is always popular!
- mkr-hn 16y ago
  It's obvious now that I think about it. Even with GPS, they're going to be told landmarks and indicators (roads and stuff) during a briefing.
  - aj700 16y ago
    Why shouldn't this break military plane GPS as much as anything else. It will also remove the ability of USAF to GPS target missiles onto US population centres, which they have no need to do anyway. They can still bomb the rest of the world no problem.
    - Kadin 16y ago
      Military GPS receivers operate on two carrier frequencies, only one of which is used by most civilian models. (And it's the shared military/civilian frequency which is adjacent to the spectrum in question.) Using two frequencies makes the military receivers more robust, and also lets them do some clever ionospheric distortion cancellation that you can't do with one channel. (Basically they get the benefits of WAAS without actually needing to receive the WAAS signal.) That said, neither the FAA or the military are going to tolerate any significant degradation of GPS, domestically or otherwise.
kpeel 16y ago
Yeah, I was joking a little. Most aircraft would still work pretty well off of inertial data. However there are quite a few weapons systems that just plain won't work without GPS. BTW, I'm not a pilot, but I work for a government aerospace contractor, so I have some experience in this.
- mkr-hn 16y ago
  I figured GPS-guided bombs would be the only thing impacted. Cruise missiles match terrain to what's stored in memory to know where to drop.
- icegreentea 16y ago
  I thought the most common ones (JDAMs) still had an inertial navigation system cause GPS/INS is used nearly everywhere. It'll probably have horrible accuracy (I guess that depends on how the coordinates sent to the bomb are handled... if it can be calculated as an offset of what the INS thinks it is, then it wouldn't be that bad). But still better then unguided bombs.
winthrowe 16y ago
I'm not actually air force, but am a bit of an aviation buff with a private license. There would be backup nav systems in manned aircraft, but several popular modern munitions are GPS guided, and I would tend to think that modern battlespace information systems require it as well. Planes wouldn't fall out of the sky, but it would be a significant departure from the ideal state.
- mkr-hn 16y ago
  If you have time, I wouldn't mind some examples. I'm curious, not doubtful. Since this thread sprung up I've wondered what might be impacted by a GPS failure.
  - winthrowe 16y ago
    Of the munitions? I hear JSOWs and especially JDAMs are popular recently. As far as BIS info, it's not something I've followed closely, but we're talking things like every plane, tank, and infantryman now (soon?) has gps and information on the location of all friendly forces is automatically shared so you cut down friendly fire. Apparently caf has more info on milspec GPS than I do, I thought that it required the same main band as civilian, and just used additional military bands to increase precision, but apparently it can function fully independently (not really surprising when you think about it). At least that gives you a little info on some of the troubles of failure of military GPS, as unlikely as that is. http://en.wikipedia.org/wiki/Joint_Stand-Off_Weapon http://en.wikipedia.org/wiki/Joint_Stand-Off_Weapon http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition
caf 16y ago
US Military GPS has access to a separate P(Y) signal on the L2 frequency that civilian GPS does not.
philwelch 16y ago
Depending on the plane, there are cases where a full systems failure knocks out every means of navigation other than "Mark I Eyeball": http://www.defenseindustrydaily.com/f22-squadron-shot-down-by-the-international-date-line-03087/ http://www.defenseindustrydaily.com/f22-squadron-shot-down-b...

oomkiller 16y ago

Actually most modern munitions are guided by inertial navigation, mainly so targets can't jam them. Aircraft etc also have this capability. They have known about the risk of jamming since the beginning, so surely they've prepared for it.

kpeel 16y ago
Very true. My answer was a bit tounge-in-cheek, I just didn't get it across properly. While losing GPS would be a problem, it certainly wouldn't bring down our military. This specific problem definitely wouldn't affect our aircraft simply because they would be at such a high altitude. Even if it was a problem, the military also has a some pretty impressive anti-jamming capability.

smallblacksun 16y ago

Conveniently, the USAF also has a lot of anti-radiation missiles that are very good at eliminating jamming sources.