Help to upgrade sof...
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Help to upgrade software on Topcon GRS-1

FNG Member

I have 2 GRS-1 units, 1 with TopSurv 7.5.1 and the other with TopSurv 8.1. I think both units are the same hardware but the 7 will only receive L1, not L2 even though it's connected to a PG-A1 external antenna. Does anyone know if that is a limitation of the TopSurv software or the hardware? Is it possible to load the TopSurv version 8 onto the unit with version 7? Thanks, Tom 

Topic starter Posted : April 8, 2020 8:54 am
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FNG Member

Hi. Do you have the topsurv 8 intaller? I think GRS-1 only track L1 signal GPS and Glonas.

Posted : June 5, 2020 5:17 pm
500+ posts Member

The GRS-1, when coupled with either a PG-A1 or PG-S1 antenna is capable of L1+L2 GPS & GLONASS.

As for the TopSURV software, do not load a different version of TopSURV without taking a screenshot of the activation codes for the current installed version.  Under the guise that the software is no longer supported, Topcon WILL NOT issue activation codes for any version of TopSURV.  They consider it obsolete software.

You should be able to load the current version of Magnet Field software, though you would have to purchase at least the GPS+ license in order to activate it.


If the GRS-1 in question does not receive L2 signals, it is likely because it was purchased as a mapping grade unit and is not capable of RTK until the necessary upgrade are purchased.  The unit should have Topcon Receiver Utility [TRU] installed on it.  If you open that app in "Receiver Managing" mode, you should be able to view the Options Authorization File [OAF] and see what is enabled.

Posted : June 12, 2020 7:02 am

200+ posts Member

Anyone open to a phone call to help me troubleshoot my GRS-1. Just bought it on eBay. I understand that it will not likely work using the 3G cellular modem because of 4G/5G taking over. I am trying to use it with a Wi-Fi hotspot. If willing, PM me. Thx. 

Posted : July 4, 2022 7:30 pm