Details about the GT-31 can still be found on the Locosys website.
This was a significant improvement to the GT-11, thanks to use of a newer GPS chipset from SiRF:
SDOP became available for the first time, allowing the Doppler speed accuracy to be estimated with 99% certainty.
The GT-31 was superseded by the GW-52 in 2015, when Locosys stopped producing the GT-31.
|Memory||~5h 30m (internal) but much more with SD card|
|Charging||Mini USB cable|
|Download||SD card or mini USB cable + NAVILINK|
|Best Formats||SiRF binary (SBN) or SiRF binary, packed (SBP)|
|GPS chipset||SiRFstar III|
|Additional Logging||Sats, HDOP, SDOP|
|Approved for GP3S||Yes|
|Approved for GPSTC||Yes|