Receiver design for doppler positioning with low earth orbit satellites and differential carrier phase measurements

A device configured to determine position based on low Earth orbit (LEO) satellite signals, the device comprising:

• a communications module configured to receive one or more low earth orbit (LEO) satellite signals, wherein the LEO satellite signals include direct quadrature phase shift keying (QPSK) signals;
• and
• a controller, coupled to the communications module, wherein the controller is configured to
• perform a Doppler frequency measurement for the quadrature phase shift keying (QPSK) signals for each downlink channel received, wherein the Doppler frequency measurement includes
• filter each received downlink channel, and
• performing a channel tracking operation for each filtered downlink channel, the channel tracking operation including an independent phase-lock loop to track each filtered downlink signal, wherein each phase-lock loop determines a Doppler shift measurement;
• and
• perform a navigation filter operation to determine clock drift based on each Doppler shift measurement from each channel tracking loop;
• and
• determine a position of the device, wherein the device determines position based on clock drift determined by the navigation filter operation and tracking data for each LEO satellite signal source.