NMEA sentences - PGLOR, GNGSA and QZGSA

Question

I'm writing an Android app that reads and parses NMEA sentences from GPS receiver and using a Nexus S phone for tests.
I'm getting GPGGA, GPGSV, GPGSA and GPRMC sentences that are pretty common and very well documented, but in addition, I'm getting next sentences and I'cant find any info about them:
PGLOR, GNGSA, QZGSA
Where I can find some docs about those sentences format?

Answer 1

I recently wrote an app that parsed the GPGGA NMEA strings, my advice is parse what you need, and leave the rest. Generally you don't need all formats, only specific ones.