I am seeing an issue where some invalid GPS coordinates get reported from time to time. Sometimes the coordinates reported are 30miles away, sometimes they are several hundred or a thousand miles away. A reboot normally fixes the issue. Anyone experiences this before? I am using GX400 with radio module MC5728. Any advice would be helpful.
Is the fix flagged as ‘valid’ when this happens 
I am having the same issue. When this happens we have a GPS fix but our satellite count is lower than when we don’t see the issue. We see satellite counts of 3 and 4 when the issue occurs. We reboot the modem and when the reboot finishes we can see the satellite counts go back up between 7 and 9 normally and the gps location is correct at that point.
It seems as if the GPS fix gets lost occasionally when the issue happens but it comes back within a minute or so. When the fix becomes valid again the location being reported is still incorrect. The 3 images show the modem details when gps fix goes from valid to invalid. Even when showing a valid gps fix the location is incorrect. In this case it is giving a point approximately 70 - 100 miles away from where the correct location should be.
[attachment=0]1 - 8 37am - gps fix valid - new.PNG[/attachment]
[attachment=2]2 - 8 37am - all data lost - new.PNG[/attachment]
[attachment=1]3 - 8 40am - gps fix back to valid with other data - new.PNG[/attachment]
The forum seems to be having problems with uploaded pictures: https://forum.sierrawireless.com/t/uploads-not-working/7673/1
Tried again without putting the pictures ‘inline’ and left them as attachments. Maybe you can see them now?
Nope - I also tried that in my other thread!
Ok, since the pictures won’t work I am going to try to relay the data displaying in the ‘GPS’ section of the GX400 when the issue happens
First Point - GPS fix indicates valid but the coordinates displayed are incorrect
GPS Fix : 1
Satellite Count : 3
Latitude : 4281784
Longitude : -9494647
Heading : 269
Speed (km/h) : 126
Engine Hours : 0
Second Point - GPS fix lost along with most other data
GPS Fix : 0
Satellite Count : 0
Latitude : 0
Longitude : 0
Heading : 270
Speed (km/h) : 0
Engine Hours : 0
Third Point - GPS fix indicates valid again but the coordinates displayed are still incorrect
GPS Fix : 1
Satellite Count : 3
Latitude : 4281784
Longitude : -9494647
Heading : 269
Speed (km/h) : 126
Engine Hours : 0