How can I get the GPS raw data (satellites pseudo range)?
If you need pseudoranges, and raw data, you will not be lucky with NMEA. You have to use the binary protocol of your receiver, E.g ublox binary for ublox receivers. Sirf binary for Sirf receivers. Sattelite raw date are available only on special receivers which have the RAW option enabled. Don´t expect that on a smartphone.
More details you find at the ublox protocol specification.
you might take a look at satinfo
http://code.google.com/p/codetastrophe/source/browse/#svn/trunk/projects/satinfo
not sure if it provides specifically what you are looking for or if it even still works on recent versions of android
Satellites pseudo-ranges are not available in the official API, neither through the GpsStatus.Listener nor the GpsStatus.NMEAListener interfaces.
The only available info available in the GpsSatellite class are:
- PRN
- azimuth
- elevation
- C/N0
- a "usedInFix" boolean.
The Android source code asks just those fields from the native code, so no hope to get it from any other Java API.
The best way for you to get this data anyway (which is not suitable for a Market-able application) would be to explore Android source code, and either find a native hook to get the data at low level and access through JNI, or recompile the full OS modifying the API to your needs (you also need to find the relevant native code for that).
Finally, if you can get the chipset to send you GRS NMEA sentences (you would get them through the standard NMEAListener interface, the difficulty is configuring the chipset to send them) you can then compute the pseudo-ranges (those sentences contain satellites' residuals)
Good luck and let me know if you try any of these ideas!