Tracking accelerator based on RISC-V custom instructions for GNSS receiver

To improve the tracking processing speed of embedded Global Navigation Satellite System (GNSS) receivers, we propose seven custom instructions and a tracking accelerator integrated into the self-developed 32-bit RISC-V processor named Prism. The accelerator can increase execution speed significantly at a reasonable area and power cost. The FPGA test and synthesis under the 40nm technology showed that the accelerator achieved 58% to 94% speed increase for three tracking loops, and 122% to 700% speed increase for seven custom instructions, at the cost of 33.1% more area and 19.8% more power consumption.