摘要
When an aircraft moves under a low carrier-to-noise ratio （CNR） or at a high speed, increasing the sensitivity of global navigation satellite system （GNSS） receiver is a goal quite hard to achieve. A novel acquisition scheme assisted with micro-electro-mechanical-sensor （MEMS） inertial navigation system （INS） is presented to estimate the Doppler caused by user dynamics relative to each satellite ahead of time. Based on tightly coupled GNSS/INS estimation algorithm, MEMS INS Doppler error that can be achieved is first described. Then, by analyzing the mean acquisition time and signal detection probability, the MEMS INS-assisted acquisition capabilities in cold, warm and hot starts are quantitatively determined and compared with the standard GNSS acquisition capability. The simulations and comparisons have shown that： the acquisition time in cold start can be shortened by at least 23 s, the time in warm start can be shortened to i s and the acquisition capability is improved 95%, and the reaequisition time in hot start can be shortened by around 0.090 s and the capability can be enhanced 40%. The results demonstrate the validity of the novel method.
When an aircraft moves under a low carrier-to-noise ratio(CNR) or at a high speed,increasing the sensitivity of global navigation satellite system(GNSS) receiver is a goal quite hard to achieve.A novel acquisition scheme assisted with micro-electro-mechanical-sensor(MEMS) inertial navigation system(INS) is presented to estimate the Doppler caused by user dynamics relative to each satellite ahead of time.Based on tightly coupled GNSS/INS estimation algorithm,MEMS INS Doppler error that can be achieved is first described.Then,by analyzing the mean acquisition time and signal detection probability,the MEMS INS-assisted acquisition capabilities in cold,warm and hot starts are quantitatively determined and compared with the standard GNSS acquisition capability.The simulations and comparisons have shown that:the acquisition time in cold start can be shortened by at least 23 s,the time in warm start can be shortened to 1 s and the acquisition capability is improved 95%,and the reacquisition time in hot start can be shortened by around 0.090 s and the capability can be enhanced 40%.The results demonstrate the validity of the novel method.
基金
the National High Technology Research and Development Program (863) of China(No.2009AA12Z322)
