An Unassisted Super-Resolution Satellite Navigation Receiver Using GPS L5 Signals

Many existing works use external devices or information, e.g., real-world maps, reference receivers, dead reckoning (DR) sensors, and multiantennas, to compensate for signal dynamics and mitigate multipath interference in global navigation satellite system (GNSS) signal reception. This article proposes a standalone global positioning system L5 receiver using the fractional Fourier transform (FRFT) in an over-one-second superlong coherent integration (S-LCI) correlating process. Then, a code phase DR method is presented in the baseband processing by leveraging the super-resolution average Doppler rate and instantaneous Doppler frequency from the S-LCI-based FRFT to enhance the code discriminating process. A software-defined radio prototype of the unassisted super-resolution receiver (U-SRR) based on the S-LCI, FRFT, and code phase DR is developed where the pilot-channel L5 signal serves for positioning. The transmitting time splicing comes from the respective frame synchronization and code phase tracking in the data and pilot channels. Real-world experiments verify the proposed U-SRR in an extremely dense urban area. Compared to the legacy L1 coarse/acquisition (C/A) signals from the u-blox ZED-F9P receiver, the code-based positioning precision is increased by 86.8% with 100% measurement availability.