I've been playing around with the APRS on FM for a few days now.
I have noticed that despite having 3, 4 or more satellites on the screen, it is very difficult to find the location. I even got to have 6 satellites, and it can't find the position.
I don't know if it can be caused by the GPS antenna, but if the receiver sees them...?
Once it has found the point, it works fine, even with 3 satellites.
Could it be that the signal is too weak to position itself? or is it a software thing?
Does it happen to anyone else?
And it doesn't seem to be a problem of poor reception because it finds the satellites in a few seconds, and in a minute you already have 4, 5 or more...
GPS slow to find location
Re: GPS slow to find location
That sounds normal for these radios.
When the GPS starts up it always has to do a cold start. (Because there is no backup battery). A cold start requires the GPS to download the Orbit data from the satellites. This can take a long time if the signal is weak or fluctuating. Keeping the GPS steady can help here as a varying signal can cause data dropouts when downloading the data.
Once the GPS has downloaded the data it can calculate the position with a much weaker signal.
Colin G4EML
When the GPS starts up it always has to do a cold start. (Because there is no backup battery). A cold start requires the GPS to download the Orbit data from the satellites. This can take a long time if the signal is weak or fluctuating. Keeping the GPS steady can help here as a varying signal can cause data dropouts when downloading the data.
Once the GPS has downloaded the data it can calculate the position with a much weaker signal.
Colin G4EML
Re: GPS slow to find location
This is normal.
The GPS module in the radio takes a long time before it outputs the location, even if there are multiple satellites in its RSSI output data.
The GPS module may be waiting for a certain level of accuracy to be achieved, but there is nothing we can do about this, becasue it does not output the location until it is happy
The GPS module in the radio takes a long time before it outputs the location, even if there are multiple satellites in its RSSI output data.
The GPS module may be waiting for a certain level of accuracy to be achieved, but there is nothing we can do about this, becasue it does not output the location until it is happy
Re: GPS slow to find location
There are some threads on improving GPS - This one is about an easy to fix manufacturing issue:
viewtopic.php?f=19&t=3184
This thread has some very detailed instructions for modifications to improve reception (toward the end of the thread):
viewtopic.php?f=19&t=2415
I found a radio I bought direct from Retevis in end of November 2023 with a manufacturer date of October 2023 had improved GPS reception out of the box, I put some comparison info in this thread on page 12:
viewtopic.php?f=19&t=2415&start=110#p28188
viewtopic.php?f=19&t=3184
This thread has some very detailed instructions for modifications to improve reception (toward the end of the thread):
viewtopic.php?f=19&t=2415
I found a radio I bought direct from Retevis in end of November 2023 with a manufacturer date of October 2023 had improved GPS reception out of the box, I put some comparison info in this thread on page 12:
viewtopic.php?f=19&t=2415&start=110#p28188