PHASE TRACKING LOOPS SUPPORTING IN THE SATELLITE NAVIGATION RECEIVER USING INERTIAL NAVIGATION SYSTEM MEASUREMENTS

Abstract

Satellite radio navigation systems make it possible to evaluate the user's state vector, use coordinates, user speed and time relative to the system scale. The requirements for the characteristics of these systems constantly depend on the fact that they have application features in their algorithms for processing radio navigation signals. One of the main characteristics of satellite radio navigation systems is the accuracy of estimating the user's state vector. This characteristic can be improved by the presence of estimates of the phase of the received radio navigation signals. In a satellite radio navigation system, phase estimation errors in the tracking loop have two components: dynamic and noise. To compensate for the noise error, it is necessary to reduce the equivalent noise band of the anti-aliasing filter of the phase tracking loop. However, the minimumpossible bandwidth of the smoothing filter is limited by the presence of consumer dynamics and the quality of the reference oscillator. As a result, in the presence of consumer dynamics, the sensitivity and reliability of phase tracking deteriorates. To compensate for the dynamic error in the phase tracking loop, information from an inertial navigation system can be used. The satellite radio navigation system and the inertial navigation system have complementary characteristics. The use of support for phase tracking loops from an inertial navigation system makes it possible to increase the sensitivity and reliability of its operation in the presence of consumer dynamics. It is assumed that with such an implementation, the sensitivity of the phase tracking loops will be limited only by the instability of the reference oscillator and the error of inertial measurements. To improve the characteristics of accuracy, sensitivity and reliability of the coherent mode of operation of the end device, an algorithm was developed to support phase tracking loops with measurements from an inertial navigation system. A study of the developed algorithm was carried out on a model that uses real measurements of satellite and inertial navigation systems as input data. The developed algorithm is implemented in the software of the NV216C-IMU inertial satellite navigation system prototype. Experimental studies were carried out in the conditions of automobile dynamics in open areas. The research results are presented in the work.