An Android app might exist for this. If it doesn’t, this could be an idea for a new app from Planet, it should be straightforward to make it.
Failing that, this can be probably set via a custom Mediatek AT command. The serial port of the X25/27 chipset should be available in the OS, at least under Android, so you’ll need to find a terminal emulator for Android (like Minicom on Linux) and find out what’s the serial port name for the AT commands. As to what’s the command and its syntax, you’d need to find a copy of Mediatek’s AT commands manual, though this won’t be easy since it is apparently a confidential document. I have found some older copies of it online, I’m not sure if they are generic manuals for all the Mediatek’s products, or for specific chipsets only, anyway I didn’t find any GPS-related command in them. It might be also possible to find the command by listing all the implemented commands via AT+CLAC (or, even better, AT&H which also briefly describes each command), provided that they are implemented. Once found, its syntax could be retrieved via the Test command, e.g. if the command is AT+EGPS, the AT+EGPS=? should return all the supported values.
Varti
