Key Technologies Research Of Satellite Timing Receivers

The technology of time transmission in many fields such as the scientificresearch, military and the economic development is widely used. With thedevelopment of science and technology, the demand of many fields to timeaccuracy is more and more high and the range demanding time synchronization ismore and more wide. So the timing technology is also rapidly developed. Bymaking use of a radio signal, time transferring and the service of comparing timeis widely carried out and Loran-C system is a representative. With thedevelopment of space technology, the method of making use of a satellite totransfer and compare time is already commonly applied. Since the satellite timeservice system has so many advantages, it gradually replaces original time servicesystem in many fields.During the process of satellite timing service, satellite timing receivers affectthe timing accuracy. Satellite timing receivers have been improved by thedigitization technology, but the high speed of processing signal and therequirement of crystal oscillators that have high performance make receiversexpensive. The goal of dissertation is to improve receivers by using the digitalsignal processing algorithm on the receiver and receiver hardware demand is notraised. The main contents of work are submitted as follows:1. The algorithms about processing signal in spread spectrum communication system, comparing the signal from satellite navigation system andthe signal from the normal spread spectrum communication system, combiningcarrier recovery algorithms and symbol timing algorithms to select the algorithmsof satellite timing receivers, analyzing the hardware structure and timing applyingmodule on satellite timing receiver.2. The theory base on digital signal processing is introduced in detail. Thealgorithms on FFT correlation method and matched filter method on searchingalgorithm, feed-forward tracking algorithm, the frequency locked loop, phaselocked loop and non-coherent delay locked loop on the tracking algorithm and theperformance about the loop filter are elaborated. The formulas and the simulationon algorithms are also given.3. Extended research is performed on the basis of the existing algorithms.the feasible way on enhancing timing performance of timing receivers through thetechnical change of receivers is provided. The research includes that theestimation of the sampling frequency offset is completed by using the codetracking loop and the accuracy of the estimated carrier phase is also enhanced, thedifference of many transforming ways from analog domain to digital domain, tworunning way on the tracking code loop, the method of non-integral sampling isused to enhance the accuracy of local code phase.4. The actual satellite signal is also used to carry on the confirmation on thealgorithms and the above-mentioned algorithms are also confirmed by using theDSP hardware platform. The contents that should simultaneously be paid attentionto are described when the algorithms are transformed from Matlab language to Clanguage in the DSP hardware platform.The above-mentioned results provide general theoretical references and a good deal of design examples for the enhancement on the performance of satellitetiming receivers.