4G Broadband May Jam GPS

[MikeD]

Whoa, gramps! Let's not go too far, I rode in a plane with LORAN once that's practically like having flown it for 1000hrs right?

But really? Never had any problems with it in the rain? At least a half dozen guys I talked to who had it in their personal airplanes all mentioned that it, "didn't work in the rain," huh. Interesting. What did you fly it in? The Hog?

Nah, was in my cargo days, a couple of our 207s and a PA-31 had it. Northstar LORAN-C system.

Never had problems in the rain or precip. Then again, in different geographic areas there may be different anomolies; such as when GPS wasn't fully up to par and there were dead spots. Was a good systems and the next best thing next to GPS. I just think we're putting all our eggs too much in the GPS basket. And that may be to our detriment if this thread is true.

 

[ppragman]

Nah, was in my cargo days, a couple of our 207s and a PA-31 had it. Northstar LORAN-C system.

Never had problems in the rain or precip. Then again, in different geographic areas there may be different anomolies; such as when GPS wasn't fully up to par and there were dead spots. Was a good systems and the next best thing next to GPS. I just think we're putting all our eggs too much in the GPS basket. And that may be to our detriment if this thread is true.

I strongly agree with this man, honestly, NDBs are the best thing in my opinion, they're simple, cheap, don't require that much maintenance (at least that's what the repair guys told me), and they have a decent amount of range. Personally, I'd like to see some more ground based infrastructure, and while I don't know what the answer is to that now that the LORAN stations are closing down.

My thought is that you could broadcast GPS signals from grounds stations. I don't know enough about the specifics of the actual signal transmitted, but my understanding is that all they're sending is the time and location of the satellites along with RAIM data. Of course, that wouldn't help us with the whole 4G jamming, but that would certainly keep the Chinese from shooting down all our equipment, at least the national infrastructure would stay intact. GPS is only as accurate as the clock in the satellite, so I suspect that you could create a lot of fairly cheap, less accurate ground systems that would combine to produce an accurate location.

 

[KSCessnaDriver]

Have alot of time using the Northstar LORAN system, and it was very good. Some who are trying to compare GPS accuracy in approach modes, to LORAN accuracy as an RNAV instrument in the enroute phase, which is all it was designed for......its apples and oranges. The LORAN was great as an RNAV in IFR, would often file /I with it.

Absolutely. Heck, when I was in my instrument class at riddle I think I was one of like 2 people who knew what the system was and had used it. I have a feel that if they would have went ahead with eLORAN, they might have been able to give us RNAV approaches. Sadly, we'll never find out

 

[MikeD]

Absolutely. Heck, when I was in my instrument class at riddle I think I was one of like 2 people who knew what the system was and had used it. I have a feel that if they would have went ahead with eLORAN, they might have been able to give us RNAV approaches. Sadly, we'll never find out

Agree on the eLORAN and what it could've been. In my Global Nav class at Riddle back in '90, we had a former KC-135 Navigator as the instructor. He trained us with the actual instruments on LORAN, VLF/OMEGA, basic Inertial systems of both regular gyro and ring laser, and the first generation of what was to be GPS. Very interesting stuff.

 

[Rivanthe5th]

I just think we're putting all our eggs too much in the GPS basket. And that may be to our detriment if this thread is true.

always been my concern as a young pilot. Everything is moving towards GPS, which is awesome and all, but, imagine if enemy nation X found a way to jam our GPS... Yeah, we can still do the basics (VOR etc...), but it'd turn into a [ mess ] in no time. Especially as they're planning on decommissioning some or all of the VOR network. I always say: Anything that can be transmitted can be jammed. It's only a matter of time.

Also, as for this thread being true or not: http://www.aviationweek.com/aw/gene...e=Cell Phone Threat Prompts GPS Jamming Study
Just happens to be one of those things they cant just switch on and say "lets see what happens!"

 

[Blackhawk]

What's also interesting is that some aircraft are being certified to require GPS under certain conditions. The DA-40/G1000 for example requires at least one GPS to be operational for night VFR and IFR flight.

 

[g4downin]

Law suit up!

 

[Bandit_Driver]

What's also interesting is that some aircraft are being certified to require GPS under certain conditions. The DA-40/G1000 for example requires at least one GPS to be operational for night VFR and IFR flight.

Sounds like some marketing weeny found a way to sell more GPS's. Pilots have been navigating in the soup for years without the GPS...don't see why it needs to be required, especially for VFR flight.


I have flown LORAN, RNAV equippend aircraft and it worked as well as GPS does today for me. The RNAV just took just a little extra effort to program. Also IIRC to shoot a LORAN approach you had to enter a correction factor.

 

[Roger, Roger]

Sounds like some marketing weeny found a way to sell more GPS's. Pilots have been navigating in the soup for years without the GPS...don't see why it needs to be required, especially for VFR flight.

I *think* it has something to do with being certificated based on EASA regs vs. FAA. There's a lot of stuff on the Diamonds that is required that is not required on, say, a Cessna for that reason.

 

[Bandit_Driver]

I *think* it has something to do with being certificated based on EASA regs vs. FAA. There's a lot of stuff on the Diamonds that is required that is not required on, say, a Cessna for that reason.

Interesting food for thought..I wasn't thinking of it quite that way.

Thanks

 

[Blackhawk]

I *think* it has something to do with being certificated based on EASA regs vs. FAA. There's a lot of stuff on the Diamonds that is required that is not required on, say, a Cessna for that reason.

I'm pretty sure that was the case.

 

[Roger, Roger]

Interesting food for thought..I wasn't thinking of it quite that way.

Thanks

It'd be an interesting comparison to take the KOEL of a same-model-year 172 with G1000 and DA40 with G1000 and compare them.

 

[flyboy6585]

Sounds like some marketing weeny found a way to sell more GPS's. Pilots have been navigating in the soup for years without the GPS...don't see why it needs to be required, especially for VFR flight.


I have flown LORAN, RNAV equippend aircraft and it worked as well as GPS does today for me. The RNAV just took just a little extra effort to program. Also IIRC to shoot a LORAN approach you had to enter a correction factor.

It has been a while since I have reviewed the G1000 system, but IIRC, the GPS is an integral part of the AHRS (attitude heading reference system) and the ADC (air data computer) and those inputs are used to assist in the determination of the quality of the output. In the even that there is a discrepancy it can "X" out the offending indications. For example, in slow flight with a massive headwind the GPS shows you going the opposite way that the magnotometer shows. Because of this apparent discrepancy the system is unsure if the heading shown is correct and "fails" the HI.

The GPS speed, direction, altitude, are all utilized as a layer of safety. Without the GPS the system will operate normally, but you lose one of those layers and should something fail at night or IFR the system might not annuciate as quickly and you might follow erronious indications.

IIRC the GPS is required to be operational at night and during IFR ops in the 172 as well.

Again, this is based off my memory of the systems and how they interact. I could be wrong.

 

[Roger, Roger]

IIRC the GPS is required to be operational at night and during IFR ops in the 172 as well.

Again, this is based off my memory of the systems and how they interact. I could be wrong.

That does not match my memory of things, but it has been a while. I think I dumped my 172 POH when I quit CFI-ing so I can't prove you wrong or right at the moment though.

 

[Bandit_Driver]

IIRC, AHRS systems don't use GPS for anything. Hell the Saab 340 was /A aircraft and AHRS. It didn't get a GPS receiver until TAWS came around and then it was so weak the GPS couldn't do NAV.

TMK the GPS Satellites each have 4 atmoic clocks using cesium 133.

MikeD, We had a similar class at WMU. VLF/OMEGA was just getting turned off but we learned it anyways.

 

[MikeD]

MikeD, We had a similar class at WMU. VLF/OMEGA was just getting turned off but we learned it anyways.

Absolutely amazing what 8 ground based stations around the world could accomplish for navigation at that time.

 

[Itchy]

Garmin does input the gps directly into the ahrs.

 

[flyboy6585]

IIRC, AHRS systems don't use GPS for anything. Hell the Saab 340 was /A aircraft and AHRS. It didn't get a GPS receiver until TAWS came around and then it was so weak the GPS couldn't do NAV.

TMK the GPS Satellites each have 4 atmoic clocks using cesium 133.

MikeD, We had a similar class at WMU. VLF/OMEGA was just getting turned off but we learned it anyways.

While most AHRS systems do not use GPS the G1000 platform does have a specifc input into the AHRS from both of the GPSs. Like I said, IIRC that input is used by the system to provide a basic fail safe for the system. You fly backwards in slow flight and the HSI gets X'ed out because the GPS says you are going the opposite direction that the magnetometer says you are and the system is unsure which is right. While it is just GPS it does provide basic heading, speed, altitude, vertical speed, turn rate, and I am sure this data can be calculated to provide a rough attitude to the AHRS. I don't know what inputs the AHRS specifcially looks at and what delta between the AHRS and GPS data is allowed before the system freaks out, but I do know that it is used for something inside that box.

Also, I would venture that the early AHRS systems (like the SAAB 340 you mentioned) were substantially bigger and had more redundant and backup systems due to their lack of external inputs than the G1000 system. The whole AHRS and ADC are in 2 LRUs that are about 4x6x12ish each.

 

[Blackhawk]

Absolutely amazing what 8 ground based stations around the world could accomplish for navigation at that time.

Back then Omega was great, but looking back not so. At the time we were comparing it to doppler navigation which... well... kind of worked. Yeah Omega would get us to the vicinity of an airfield... but that seemed to be about it. Granted, my use was limited to Korea.