Jump to content

SA and Old GPS Units

Guest fryed

Recommended Posts

My brother was complaining that his older GPS was no longer functioning since the Selective Availability was turned off. I don't know what make or model he has or any of the details when he says it "no longer works". It didn't seem likely to me that just because SA was turned off that his receiver should suddenly stop working. Has anyone heard of this happening? Or is it most likely a coincidence. My thinking was that maybe the internal battery picked that time to finally die. Any thoughts anyone?

Link to comment
Guest OregonSurveyor

I agree, the cause would not be that SA is off. I'd try fresh batteries. Does it turn on? Does it just give bad results, or does it fail to initialize on the satelites. If he moved over 300 miles since his last use he may need to go through the full re-initialization routine. Hope something works for him.



Lat. N 45d-30.6875'

Long. W 122d-37.2055'



Link to comment

Depending on the age and make of the GPS it is probably a Y2K or week roll over problem if the unit will power up and talk to satellites but not get a position. Most GPS were Y2K compatible but a small number were not. Also GPS counts weeks from start-up of the GPS network (not the individual unit). Well they only count to 1024 and then roll over. Again most units don't have a problem with this but a slightly larger number, then the Y2K units, have a rollover problem.


If the unit is not receiving the satellites or if it does not power up then its a hardware malfunction. The likely hood of it being related to the end of SA is unlikely.


If it does power on. Figure out how to do a reinitialization and leave it on for several hours with a good veiw of the sky. If it still works it will take it a while to get all the data it need from the satellites to get a lock on. The longer you leave it on after it does lock on the better.



Link to comment
Guest GPSlooney

I've a Garmin GPS 45XL, which is allready 5 years old and it still functions after DOD removed SA. It even got more accurate (It's supposed to be). If his GPS poweres up, I would suggest to try "search-the-sky", otherwise pay a visit to the manufacturers site to see if this could be a Y2K problem (as mentioned in the other answers)

Link to comment
Guest swangner

I agree, it's definitely not an issue related to the turning off of selective availability (it's probably just a coincidence that it happened around the same time).


SA was a degradation in the satellite signals, and had nothing to do with the receiver units.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...