Research Of The Tracking Method Based On The New Characteristics Satellite Navigation Signal

The basic function of the satellite navigation system is to provide accurate, real-time, continuous position, velocity and time information to various kinds of users and the movement platform. At present it has basically replaced the radio navigation, the astronomical measurement and the tradition geodetic measurement technology, becoming the navigation and positioning technology which is widely used in human activities. Satellite signal synchronization is the premise of the signal gain, so the synchronization system is the key of the satellite navigation system. The key of synchronization is the the tracking technology. However, with the continuous demand improvement of new generation military and civilian applications, various countries propose and apply the new characteristic satellite navigation signal unceasingly, such as the BOC modulation, TDDM modulation mechanism signal, and so on. Precisely because of the emergence of the new characteristic signal, the traditional tracking method has not been able to meet the need, and it also presents the new challenge for tracking technology. Therefore, the tracking method of the new characteristic satellite navigation signal is studied in this article.On the basis of the study of common tracking methods, in view of the fission frequency spectrum characteristic of the BOC modulation technology and the multi-peak value characteristic of its autocorrelation function, very-early and very-late locked loop and costas loop tracking methods are adopted in this article. In view of the odd modulation and the even not-modulation of the TDDM modulation technology, an improved PLL is adopted to carry on the carrier tracking, in which the received signal is divided into two groups. And for PN code tracking, the carrier auxiliary code tracking technology is adopted to reduce the PN tracking threshold. Based on this, the tracking method of the BOC-TDDM integrated modulation signal is further studied. Considering the characteristics of two kinds of the modulation, the very-early and very-late tracking and the carrier auxiliary code technology are combined for PN code tracking, the multi-channel improved PLL is adopted on carrier tracking.Usually in the low dynamic situation, the Doppler shift is small; it is easy to realize the synchronization tracking. But because in the high dynamic environment the carrier mobility is very big, the Doppler caused is very big, which makes the usual tracking loop hardly reliable operation. In view of this, the signal synchronization tracking method in the high dynamic environment is studied finally in this article. In the view of the characteristics of the new features satellite navigation signal, the string-union transform and the intelligent fuzzy logic-based tracking loop are combined for the carrier track, and it is simulated.