Research And Implement Of Positioning Algorithm In Multi-Mode GNSS Receiver Based On TMS320C6747

Global Navigation Satellite System (GNSS) has been paid a lot of attention to and widely used in the whole world, because of its high accuracy, global, real-time and all-weather application features since its birth. And GNSS ushers in a new era of navigation system.Today, GNSS system applications are far beyond the original scope of the designer's imagination, it has developed into many military and civilian fields. It provides support not only from individual soldiers to the various types of tanks, warships, aircraft and other military platforms, but also for long-range precisely-guided weapons.This paper mainly focuses on research and implement of the positioning algorithm in multi-mode GNSS receiver based on TMS320C6747.First, the paper particularly describes the details of positioning principles and design process of the multi-mode GNSS receiver, then introduces the GNSS time and coordinate systems and the conversion relationship between the coordinate systems briefly. The paper introduces the content and format of navigation message taking GPS as an example, and gives the algorithm of calculating satellite position and velocity; particularly describes the details of the composition, working principle, function modules, hardware and software architecture of multi-mode GNSS receiver. Secondly, the paper presents the research and implement of three kinds of positioning algorithms in multi-mode GNSS which are single-constellation four-satellite positioning algorithm, single-constellation multi-satellite positioning algorithm and multi-constellation integrated positioning algorithm. Thirdly, the paper introduces the research and implement of four kinds of algorithms to improve the accuracy in multi-mode GNSS, which are fast satellite selection algorithm, RAIM algorithm, error correction, pseudo-range smoothing algorithm. Finally, the paper describes the two optimization scheme of the multi-mode GNSS receiver (time and space optimization based on the TMS320C6747). During the long time testing, the GNSS receiver can position stably, the parameters and indicators can achieve the requirements of the test system, and the positioning efficiency improves from 50Hz to 100Hz.