Research On Multipath Interference Suppression Of Navigation Receiver In Non-Gaussian Condition

As the continuous development of science and technology in the21st century, satellitenavigation technology has been applied to various fields, it has become an integral part ofdaily life, it has many advantages, such as high precision, all-weather, global coverage thatother navigation equipments can not match. In the measurement of satellite navigation system,multipath has become the bottleneck to curb its positioning accuracy, reliability.As the signal propagation paths are unpredictable, the number of multipath signals, theattenuator amplitude and paths can not be set model, and it leads us not to predict or eveneliminate the multipaths by some means, and the problem of eliminating multipath error is thehotspot in the satellite navigation field. Over the years there have been many multipathmitigation techniques, such as narrow-related technologies and multipath estimate delay lockloop (MEDLL) technology, but these are taken into account under the Gaussian assumption.However, with the electromagnetic environment is becoming more complex, and a variety ofintentional or unintentional RF interference is increasing, especially in the electroniccountemeasures, that makes the receiver’s working environment present non-Gaussiancharacteristics. The performance of the optimal signal processing algorithms designed underGaussian assumptions usually significantly degenerate, even can not work. Therefore, theresearch of multipath mitigation techniques under non-Gaussian is very necessary.Firstly, in this paper, some multipath mitigation techniques widely used presently areanalysed and compared combine with the status of techniques development at home andabroad. Based on the analysis and discussion of the mechanism of multipath signal generation,characteristics and the principle of navigation receiver, the paper deduces and simulates therelationship between code tracking error, carrier tracking error that caused by multipath errorand parameters of multipath signal, it describes and simulates the existing typical multipathmitigation techniques. Then, based on the analysis of non-Gaussian noise, two multipathmitigation programs are proposed. One is based on the adaptive filter, which elimintes themultipath signals through estimating their magnitude and delay. During studying thecharacteristics of pseudo-code autocorrelation curve with the existence of the multipathsignals, the other technique which make use of characteristics that the curve singular pointscan be dectected by wavelet transform is prposed, then a novel pseudo-code tracking loop ispresented. By the way, the feasibility of above programs is proved accrording simulations.Finally, the proposed programs are designed by FPGA through hardware and software platforms in EP1S80B956C6chip.