The Improvement Of Altitude Measurement Method For VHF Radar And Engineering Implementation

VHF radar has great advantages in anti-radiation, anti-interference and long range detection, so many countries pay much attention to it. But VHF radar has a wide beam, so that a beam will contain both direct wave and reflection wave. Existing the phenomenon of beam beating the ground in the low elevation, which causes a beam split and cocking-up on the beam. Direct wave and reflected wave unable to be distinguished, which will lead to error of measurement.The main work of this paper is to derive a super resolution algorithm for engineering implementation. According to the requirement of different position, modify VHF radar altimetry project implementation plan. Then optimize and design of the program. The main work arrangement of this paper is as follows.Firstly, it talks about several algorithms of altitude measurement VHF radar, such as DBF, MUSIC, AP and SVML, and makes preliminary simulation about these algorithms. Based on the measured data from the field experiments, these altitude estimation are simulated. Then a performance comparison of all these algorithms is presented. Relevant algorithms selected apply to engineering implementationSecondly, the hardware structure of the signal processing platform has been introduced briefly. The altimetry processing board topology has been introduced briefly also. Then this paper discusses a detailed introduction of a VHF radar altitude measurement project implementation plan. At last, the function and realization of each module in the project are analyzed in detail.Finally, the optimization design of the assembly sub function and the statistics of the changes of the instruction cycles and computing time have been given, based on several measuring sub function for the same goal in before and after optimization. The structure of the program is adjusted according to the needs of engineering practice. The new project increases the parts of receiving, calibration and send of the terrain data. Pulse pressure data is received in the DSP memory. The program truncates the invalid data. Then transferred to SDRAM. The elevation range is set according to the elevation code. With a bit of wave elevation jump, must ensure that the synchronous execution of 4 pieces of DSP in the same group. Interrupt sub function has been changed to ensure that the process is not interrupted by the interruption of the outside and running normally. The new program increases the matching of the pulse pressure data and detecting results in order to guarantee the validity of the target height. Don't need to calculate, if they do not match. In order to reduce the influence of the secondary valve on the angle measurement results, the DBF coarse sub function is added a window. The new project gives a solution to the double peaks problem in the SVML algorithm. Through the optimization design, real-time and stability are both improved in the altitude measurement program.