Russia launches final satellites for its own GPS...

[n468ac]

http://www.reuters.com/article/techn...10281920071225

How long do you think our aviation GPS systems will use both?

I'm surprised that Garmin doesn't have a GPS system using both systems yet. Even if it doesn't go into effect completely until 2009 ... it has to work somewhat today with 21 out of the 24 satellites already up there ... don't you think?

I hope it would be a good backup for the US GPS ‘drop outs’ some of us have seen.

[Ron Lee]

I don't track the Russian system that closely but it seems like it was only recently that they allowed civil use. Thus there was no incentive to create GPS/GLONASS receivers.

Personally, I would rather see the DOT finally commit to having a modernized LORAN remain and have hybrid GPS/LORAN receivers.

I am surprised that you have seen GPS dropouts and would like details on the circumstances surrounding any such event.

IF Galileo becomes a reality then you can expect GPS/Galileo receivers but I would not go out and buy a new GNS 430 just to get Galileo signals.

The last paragraph in that article states " Officials said GLONASS would mainly be used alongside the U.S. global positioning system, which Washington can switch off for civilian subscribers, as it did during recent military operations in Iraq."

I would like to see proof that GPS was shut off to civil users globally. I don't believe it.

[n468ac]

I haven?t personally seen GPS ?drop outs?, but others have posted on Van?s air force that they experienced them. I have also seen notiams that reference GPS issues.

I agree with you on a LORAN / GPS system would be best, but I think the market would be more world wide for a US GPS / XXX (Russian GPS or EU GPS or both) solution.

---Conspiracy Alert---

I always think, in the back of my mind, if another 911 was happening the US Military/FAA, may disable or greatly change the GPS positioning to help delay any aircraft trying to get to a major city, giving them time to intercept. And what would happen to the many of use that fly via GPS and really don?t pay the attention to our other navigation sources as we should. How long would it take you to figure out your not were the GPS said you are?

---End Conspiracy Alert---


http://www.navcen.uscg.gov/gps/gpsno...terference.pdf

http://www.navcen.uscg.gov/gps/statu...utage_info.htm

[Ron Lee]

If you look at the performance charts you may see places where PDOP is 6-9 and assume that it means degraded performance.

Hardly.

A PDOP of 9 nowadays with a signal in space accuracy so much better than when GPS started is still more than adequate for our flying. Even when SA was on if I could not find an airport using GPS then I should not have been flying.

Indivdual satellite outages happen all the time. It does not mean that you will not be able to get a 3-D much less 2-D solution.

You should note that if an airline has GPS it probably also has DME, inertial and maybe an FMS. If GPS is down they can still navigate.

PS: The Russian equivalent to GPS is GLONASS and the proposed EU equivalent is Galileo.

[Ironflight]

I doubt that I'd invest in a GLONASS receiver unless it pretty much came free - I have been watching the Russian system struggle for funds for fifteen years now, and even if they do have a complete constellation at one moment in time, I would not be surprised if they aren't able to keep it all operating - there are a lot of dead Russian birds up there.

I'm also not that worried that we'll see the entire GPS constellation turned off. Sure, it could happen if the leadership decided it - but then wouldn't they also turn off the Loran as well, and heck, might as well turn off the VOR's just to be sure!

I make a bad conspiracy theorist...

Paul

[David-aviator]

Originally Posted by Ironflight

I doubt that I'd invest in a GLONASS receiver unless it pretty much came free - I have been watching the Russian system struggle for funds for fifteen years now, and even if they do have a complete constellation at one moment in time, I would not be surprised if they aren't able to keep it all operating - there are a lot of dead Russian birds up there.

I'm also not that worried that we'll see the entire GPS constellation turned off. Sure, it could happen if the leadership decided it - but then wouldn't they also turn off the Loran as well, and heck, might as well turn off the VOR's just to be sure!

I make a bad conspiracy theorist...

Paul

...and why not rush out and buy the latest aviation charts before they shut down the presses.....thank goodness there is no switches for the magnetic poles.

[n468ac]

Originally Posted by Ironflight

I make a bad conspiracy theorist...

Paul

so do I

[n468ac]

[quote=David-aviator;183683thank goodness there is no switches for the magnetic poles. [/quote]


You never know ... the military may be able to do that too, with help from the little gray men Roswell UFO Incident

[Greg Arehart]

Well, the magnetic poles DO switch from natural causes on occasion. This probably occurs over the course of a few years to a few tens of years, so there should be plenty of time to adapt.

Greg
(geologist)

[Bill Palmer]

The GPS control segment has the ability to activate "spoofing" or "selective availability" over selected areas of the globe. In other words, the control segment does not turn the entire GPS system off; it selectively turns the system "off" over a programmed geographic area. More accurately, the signals coming from the satellites are "spoofed" over a selected area to degrade/alter the position information. Obviously, the "selective availability" feature is needed to deny enemy access to accurate positioning in a battle area such as Iraq. U.S. military GPS receivers see through "spoofing;" your Garmin 496, and enemy GPS receivers, cannot.

The reason that we may occasionally encounter problems with our civilian GPS units stateside is that the military needs to test both the GPS system and military gound receivers in simulated combat conditions. I believe these tests are announced by NOTAM. Of course, the testing mainly occurs in restricted areas, but your civilian GPS unit might go "belly up" from a position standpoint if you're close enough to the testing area.

Take Care!

Bill Palmer