Algorithm research showing high-dynamic GPS software receiver
Hui Hu, Na Wei · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2009
ABSTRACT In the paper, it completed the hardware platform of software receiver making use of TMS320C6713, GP2010 and GP2021. Comparing to the system based on the core of TMS320C32 when the other hardware, software and performance index unchanged, the idleness of this system has improved from 13% to 67%. As for the software, the algorithms choosing of acquisition, code tracking and carrier tracking and the relation between the parameters and dynamic performance of GPS receiver have been studied in the paper. Moreover, the experimental results indicated the positioning precision of this GPS receiver could amount to 15m under the condition that the velocity, accelerator, change rate of accelerator and data update rate of carrier were 12km/s, 10g, 10g/s and 10Hz respectively. Keywords: GPS software receivers, High-dynamic, acquisition, code tracking, carrier tracking 1. INTRODUCTION Generally, the characteristics of high-dynamic carrier is under the condition of large velocity, large accelerator and large change rate of accelerator, correspondingly, the Doppler shift, change rate of Doppler shift and secondary change rate of Doppler shift are quite large, which brings forward a high requirement to demodulate data correctly. Our team has developed the GPS software receiver as the foundation of TMS320C32 in the past whose idleness is only 13% under the condition [1] that the carrier velocity is 10 km/s, acceleration is 4g, change rate of acceleration is 1g/s and data update rate is 1Hz. So it is essential to improve hardware platform and software algorithm to develop higher dynamic GPS receiver which can work well under the most difficult condition with data update rate of 10 Hz that the velocity is 12 km/s; accelerator is 10g and change rate of accelerator is 10 g/s. According to this technical index, the range of Doppler shift is -63 kHz ~63 kHz, the frequency change rate is 525 Hz/s and the secondary change rate is 525 Hz/s