GPS Receiver for DSP-based missile carrier
|School||Nanjing University of Technology and Engineering|
|Keywords||rocket projectile GPS receiver acquisition tracking navigation solution DSP|
Rockets projectile act the role of long-range attacking weapon, and the research and development of its guidance & control technology has attracted significant attention. One important research direction is increase of rockets range, as well as improvement in the guidance accuracy of long-range rockets. The GPS application to aerospace and military guidance is maturing day after day, and domestic BD satellite navigation system is being put into operation. Positioning guidance of rockets through the satellite navigation is of great significance.Rocket projectile is a high airspace, wide speed range, high dynamic acceleration and jerk guided munition. This paper analyzes the composition and principle of GPS system, general structure of the receiver and the problem caused by high dynamic environment for the receiver’s precisely positioning. How to achieve fast signal acquisition and steady tracking is a key technology that high dynamic receiver need to resolve. Receivers bear the high dynamic acceleration and jerk in the launch of rocket projectile, so the captured satellite signal is easy to be lost. Considering this appearance, this paper analysed features of classic time-domain sliding correlation acquisition algorithm and frequency domain FFT fast acquisition algorithm, and raised a method that increase the external auxiliary information to reduce the loss of lock re-capture time algorithm. On the other hand, high range of speed an acceleration require wide bandwidth of tracking loop. however, increasing the loop bandwidth would make more noise, against to the steady-state tracking of the signal, and reduce the accuracy of the pseudo range measurement value s& carrier phase measurements. Aiming at this problem, this paper analyzed the characteristics of Costas phase-locked loop, frequency-locked loop and a typical code delay-locked loop, and used two-order FLL assist third-order Costa PLL for Carrier phase tracking loop and traditional Delay-locked code loop, also designed the appropriate loop-filter.On the basis of algorithm research and receiver development at home and abroad, this paper used DSP/FPGA hardware structure to design, and researched signal acquisition, tracking algorithm and navigation positioning implementation in DSP platform. Finally semi-physical simulation experiment was performed through GPS/BD satellite navigation signal simulator, testing and analyzing the tracking performance of receiver that work at low & high dynamic environment.