Algorithm Design And Implementation On Acquisition Of High Dynamic And Weak AltBOC Signals

With the development of space rendezvous and docking technology, it has played an increasingly important role in our country’s space industry. As the "eyes" of the space rendezvous and docking technology, the measurement system is completed by radar of rendezvous and docking. The acquisition of the signal in space rendezvous and docking radar is the foundation of the whole measurement system. Therefore, the study of space rendezvous and docking radar signal acquisition is of great significance. AltBOC signals as a new navigation spread spectrum system, have shown a superior performance to conventional BPSK signal and QPSK signal in many ways. The study of the acquisition methods on this new navigation spread spectrum also has important significance. Therefore, this article is based on the weak space rendezvous and docking radar signals in high dynamic environment. It has a study on the acquisition algorithm of AltBOC constant envelope signals and its implementation.This paper first describes generation methods of constant envelope AltBOC signal and its important properties such as power spectrum, correlation peaks, to provide a basis for further research on acquisition algorithms. Then, the paper analyzed and compared the advantages and disadvantages of the basic search strategies on signal acquisition, basic accumulation algorithm and AltBOC signal acquisition methods. By the comparing, we identified the main method of the acquisition algorithm. After that,we used pure carrier guidance methods to complete the acquisition of weak constant envelope AltBOC signals in a high dynamic simulation environment. Furthermore,through the use of space rendezvous and docking radar interferometer antenna we built an antenna array group, to improve the signal to noise ratio of the received signal and the acquisition sensitivity, reduces the time needed for coherent integration.This article analyzed the role and effectiveness of non-coherent integration from the aspect of the the probability distribution. Described that non-coherent integration does not change the ratio between the mean of signal power and the mean of noise power and it can improve the probability of signal detection. This paper described the fact that when captured constant envelope AltBOC signals using BPSK-like method and bilateral combined coherent method, there is a inequality between the phase of upper and lower band. And we improved this method by changing the phase of upper andlower band. In this paper we simplified the antenna arraying process and got a good effects with the specific circumstances of the rendezvous and docking radar interferometer.