Posted on 01/05/2019 7:35:27 AM PST by Richard from IL
I was recently on a podcast with an Army LtC and Captain who are stationed in Korea discussing the history of GPS.
Everyone should still learn wilderness navigation using topo maps and compass.
About 5 years ago, it took less than two minutes.
My favorite story is my buddy....said he got to his brothers using his GPS unit with no problem.
Then I asked Richard how many times he had driven to his brothers in the last ten years.
Agreed!
When I driving from Chicago to Dallas two years ago, GPS saved my bacon by alerting me to a major traffic jam from a collision. By showing an alternative route which I would not have found since I didn’t know the area, it saved me an hour or two and much aggravation.
And if you are going to be in the wilderness then get a professional GPS unit. Don’t rely on your phone. But do bring your for emergency calls and you can give your position to someone in an emergency. Surprisingly, a cell phone can work sometimes.
Make sure that you put the phone in a sealed baggie.
Agreed! GPS is the great legacy of my Dad to the world. My website is www.gpsdeclassified.com
I was an early consumer back in the 90s and before Clinton authorized the government to unlock the precision. I have seen the evolution.
But remember too that the it can be disabled at any time. No doubt there is an on-off switch in the system. That is why people should learn how to navigate without them. That includes airplane navigation systems.
As a student pilot, I used to keep my old car GPS in my pocket so that I had a backup to the old navigation stuff on the Cessna 172 which had NO GPS. On one of my cross country solo flights, it saved my sorta lost self when I was south of the airport and I thought I was north of it.
On my sailboat, I had at least THREE independent GPS units since when off the coast out of sight of land, GPS had me spoiled very quickly. But I always had charts on the airplane and the boat that allowed a DR plot to be started if the electronics failed for whatever reason.
The cell phones are pretty good these days. Wonder if it uses a combination of the telephone network and the GPS to narrow down position. My GPS unit was having difficulty because of a foggy overcast day but my phone was able to find a waypoint. There wasn't a phone network in the area after we traveled a bit in a remote area.
The tricky thing for a GPS is finding the satellites and position when the GPS unit has been moved a distance. Takes longer. The telephone network can narrow down the position so that the GPS can find its position faster... if it is implemented that way.
Selective availability is obsolete due to the existence of Glonass, Galileo and Beideu. But if you’re in a GPS denied area due to jamming or spoofing, you need backup systems ready to go.
Selective availability still provided reasonable accuracy, too if some kind of weapon were to be used or targeting system were to be used.
My Dad in retirement was restoring covered bridges in NH and Vermont. I was driving with him circa 1992 to the different bridges and he was using a handheld Garmin to map their positions. He cursed SA for its making the positions less accurate. A large percentage of new civilian receivers use all four worldwide GNSS systems (Japan and India have regional systems). If SA was turned on for GPS, they can rely on the other three systems. So yes, SA is useless today.
That’s good to know.
Use to collect GPS with US Air force introduced error (selective availability) and had to obtain file from a nearby CORS (CORS stands for Continuously Operating Reference Stations)to remove the errors. Some of SA error looked like a sine wave others scatter point plots.
Disabling GPS is a very difficult decision that would be the last step in a conflict. Worldwide GPS is used by civilians, more so than military, and if you turn it off then untold jets and ships and such would be severely hampered in their ability to operate safely.
Please see Post 16.
Government has the ability to turn it off. Just vary difficult to make that decision.
I always wondered how effective SA was. With it enabled, there was still decent accuracy. Maybe 50ft. Certainly accurate enough for a missile targeting system. So maybe the conclusion from the government was why bother. However I do believe that there is more to SA - a simple encryption algorithm could disable the system completely.
Also, where are the other satellites positioned? Satellite positioning is important. Also, the number if satellites affects accuracy.
That makes sense. Thanks.
Also the system runs software which allows for updates and modifications. Easy to reconfigure the individual satellites and system. There is constant communication with the constellation for health and other details.
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