Research On Pulsar Recognition Algorithm And Pulsar Vector Measurement

Autonomous navigation, which significantly ensures the accomplishment of spacecraft missions during on-orbit operation, is a key technology in the aerospace domain. Based on the characteristics of pulsar signals, this dissertation researches on the pulsar navigation, and puts emphasises on the pulsar recognition algorithm and pulsar vector measurement technology. Main content and method in this dissertation are as follows:Starting from the fundamental of pulsar, this dissertation summarizes the developing history and current research of spacecraft navigation technology based on pulsar. In order to prepare for the next research, the engineering applications of current pulsar recognition method and attitude determination method in space is discussed.To address the issue of the noise influence on the signal recognition of pulsars, this dissertation analyses the characteristics of pulsar signal. Then the emprical mode decomposition method and wavelet transform method are used in the denoising processing of pulsar signals. Through simulations, it can be affirmed that the denoising of pulsar signals is implemented effectively via both of these two methods. And from the comparing result, wavelet transform method is proved to be the better.In order to recognising pulsar signal further, based on the above denoising processing, this dissertation combines singular value decomposition with the emprical mode decomposition and wavelet transform respectively to extract signal features. According to the nearest principle, the features extracted matches with that of model pulsar. So the recognition of pulsar signal is accomplished. Then the simulation proves the effectiveness of the two method used above.In order to apply pulsar signal into the attitude determination system of spacecraft, this dissertation presentes a three-plane & four-plane principle, which can measure pulsar vectors effectively. The sensor, which is designed by three-plane & four-plane structure, receives the pulsar energy on every plane, although the energy received by different plant is various. Considering the geometry relationship of the planes, it is reasonable to get the pulsar vectors through computing the amplitude and angle of pulsar signal. Combining the principle of dual-vector attitude determination, the attitude of spacecraft can be determination.