无人机航测高精度 RTK 接收机信号捕获与跟踪仿真方法研究

近年来以载波相位差分技术为核心的实时动态(real-time kinematic, RTK)高精度卫星定位技术在测绘领域迅速发展, 基于 RTK 定位原理,以轻小型化、高精度、稳定快速卫星定位接收机为目标,研究无人机 RTK 接收机的多系统多频段全球导航 卫星系统(global navigation satellite system,GNSS)信号处理技术,包括 GNSS 多频射频前端处理、基带信号处理关键技术。 通过 专业仿真手段可以得出设计的射频前端接收灵敏度高于-130 dBm,对 6 758 个采样点搜索捕获的执行时间仅为 0. 68 s,捕获频 移误差约为多普勒频移的 0. 932%,载波跟踪稳定后频率误差基本集中在 0. 75 kHz 以下。 仿真结果表明,设计的 GNSS 信号处 理模块符合实际的多频 RTK 定位接收机要求。

Research on simulation method of signal acquisition and tracking of UAV aerial survey high precision RTK receiver

In recent years, the real-time kinematic (RTK) high-precision satellite positioning technology with carrier phase difference technology as the core has developed rapidly in the field of surveying and mapping. This article is based on the RTK positioning principle, aiming at light and miniaturization, high precision, stable and fast satellite positioning receivers, the focus is on multi-system and multi-band Global Navigation Satellite System (GNSS) signal processing technology, including the GNSS multi-frequency RF front-end processing and baseband signal processing key technologies of the UAV RTK receiver. Through professional simulation methods, it can be concluded that the designed RF front-end receiving sensitivity is higher than -130 dBm. The execution time for searching and capturing 6 758 sampling points is only 0. 68 s, and the capture frequency shift error is about 0. 932% of the Doppler frequency shift, and the frequency error after the GNSS signal carrier tracking stabilizes is basically concentrated below 0. 75 kHz. The simulation results show that the designed GNSS signal processing module meets the requirements of the actual multi-frequency RTK positioning receiver.