OESF Portables Forum
Model Specific Forums => Gemini PDA => Gemini PDA - Hardware => Topic started by: Nicole Faerber on March 03, 2019, 10:45:11 am
-
Hi,
according to the Mediatec specs the implemented GNSS is capable of multi constellation GNSS reception. It supports GPS, GLONASS, Beidou and Galileo, but not at the same time, "only" three can be selected at once. By default the Gemini seems to be configured to GPS+GLONASS+Beidou, which makes sense in China. But in Europe it would make more sense to replace Beidou with Galileo, especially since the Galileo constellation will be completed soon and Galileo just announced that the high precision mode (down to 20cm accuracy!) will become a free general service.
Is this possible? And if yes, how?
It should be fairly easy to do, technically, but documentation is a little hard to find.
Cheers
nicole
-
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
-
I have done some additional tests: I have set my Gemini in the MTK Engineer mode (see https://www.oesf.org/forum/index.php?showtopic=35136) (https://www.oesf.org/forum/index.php?showtopic=35136)), as I have read that on other MTK-based devices it has an AT commands shell, but unfortunately, at least on my Gemini, it is not available. The Engineer mode also has a comprehensive GPS settings page ("Location Based Service" under the "Location" tab), but I have not been able to find there any setting for the GPS, GLONASS, Beidou and/or Galileo type of networks. There's only a setting for Assisted GPS (SIB8/SIB16, A-GLONASS and A-Beidou), but it's not what we're searching for. I'll keep looking for a solution.
Varti