Digital Radar Technique Research Of Vehicle-Flux Detecting Radar Based On DSP

With the development of Intelligent Transportation Systems(ITS) in the construction of city transportation, each part of the systems interacts with each other much more closely than ever before. Meanwhile, the technologies applied in ITS have changed greatly, which are faster, more precise and compatible. The vehicle-flux detecting system, which is the key knot of the whole ITS chain, has been improved as well. The vehicle volume detector has been changed from the single touched loop to mixed untouched methods. As one typical kind of non-touch detecting instrument, microwave vehicle-flux detecting radar is of many excellent characteristics and has been widely used.Based on the detecting principles and the various applications of the first generation microwave vehicle-flux detecting FMCW radar, this paper aims at the thorough research, design and improvement of the hardware and software of digital radar technologies. Furthermore, to lay solid foundations for the industrialization of the radar sets and satisfy sorts of needs when embedded into broader ITS, this paper designs and implemented an all-day flux-detecting system with high accuracy, multiple functions and continuous development. Also many kinds of practical problems met in the industrialization have been solved in this paper.In the beginning, how the radar practically works is described in detail and different radar mechanisms and their applications are discussed. According to the requirements of the application environment of the system, how to fix the specific parameters and functions, such as the mechanism and the working frequency, are specifically introduced.In order to minimize the detecting radar system and make it more convenient in use,a lot of digital techniques are needed. As to the first generation of this radar system which is based on ARM, DSP and FPGA, we can see that it is very complicated and too big to be integrated with the front of radar. What's more, most of the chips are not fully utilized. In this paper, based on DSP chips, a new system to implement all the required and additional functions are designed. The developing scheme of the DSP chip is discussed and the architectures of the hardware and software are proposed.On the other side, the designs of the arithmetic of the system are also essential which can guarantee the detecting accuracy. In chapter four, the original arithmetic structure is divided into several smaller modules. As to each module, the improving methods are presented and proved by reasoning and calculating. In the signal sampling module, the optimization of the sampling frequency is realized and the normalized frequency transition is implemented in DSP. Additionally, in the target-judgment module, multi-judgment detecting method is successfully applied so as to get rid of the consequences of zero signal and make the judgment of target cars more precise. Finally, a recognizing method of background power spectrum is introduced as well as the reason why it significantly improves the detecting accuracy. Also it has been transplanted into DSP and proved effective through a large amount of experiments.The results of field experiments and reliability tests indicate that this microwave vehicle-flux detecting radar is efficient and has good performances. In the meanwhile, through the analysis and test of the experimental datas, some disadvantages have been found. Therefore, several plans based on the existed chips to improve this system are discussed such as the generation of moduling signals by DMA, the application of RTC interrupt and the Modbus protocols in the communication module. In the end, the system is reconstructed based on TMS320VC5502, for its advantages that can't be derived in TMS320VC5416.