[superlopez] sent in this detailed article (mirrored here and here) which describes how to build a GPS and GLONASS (the Russian ... GPS unit just needs a better antenna, check out [Will]’s ...

The sensor forms GPS and/or GLONASS navigation raw measurements and data using the digital samples, coming from ADC. Signals acquisition, tracking, data decoding, synchronization etc are fully ...

NT1021 is a single-chip dual-channel RF front-end consuming a very low power (47 mW typical at 2.1 V) and performing a simultaneous reception of both GPS/Galileo/BeiDou and GLONASS signals ...