Study On Key Techniques Of The Generating And Receiving Channel For GNSS Modernization

The applying of the new navigation signal solves the problem of spectrum crowding, brings better tracking accuracy and interference suppression in the Modern navigation systems. However, because of the new signal system expanding the signal bandwidth and spectral splitting and multi-correlation peaks characteristic, it makes its navigation channel amplitude and phase characteristics more sensitive. At the same time, the satellite high power amplifier nonlinear effects the spread of spectrum and phase distortion seriously affects the performance of modern navigation signal reception. The emergence of modern signal system brings a great challenge to the channel designing of navigation signals. To solve all these problems, the main innovative work and research results comes as follows:(1)In view of the existing nonlinear channel is not stack previous navigation channel modeling and analysis method, build a channel and receiving channel separation problems, put forward a kind of polar coordinates all link amplitude and phase analysis model is based on independent analysis, the superposition of power loss and phase noise of the model will be memoryless nonlinear channel is equivalent to bring for the expansion of the spectrum the memory nonlinear channel, equivalent to the superposition of the linear time invariant system and the nonlinear static factor, thereby establishing the navigation channel full link analysis of the most simple channel model, solves the generated channel and receiving unified analysis and evaluation of channel problem.(2) In view of the ranging accuracy and zero BOC receiver under arbitrary linear channel has no analytical method of this one problem, establish the analysis model of arbitrary linear channel BOC receiver based on ranging precision and zero value, deduced strictly based on non coherent early late code tracking loop in PN code tracking accuracy and tracking accuracy expression carrier multiplier based on estimator. Based on the theory of BOC receiver with a communication channel, the tracking precision and zero conducted in-depth analysis, analysis shows that: the influence of main channel BOC receiver range precision and zero factor is the group delay characteristics, the same group delay channel conditions, the accuracy of BOC ranging signals with the increase of modulation order and gradually deteriorated, in deterioration in pseudo code ranging accuracy close to its power spectrum near the main valve position group delay caused by the fluctuation of the most obvious, and the receiver to achieve narrow interval structure compared to the standard interval structure more robust. Subcarrier phase elimination algorithm due to the introduction of the cross-correlation function to compensate the channel characteristics, the sensitive degree of lower on the channel characteristics. The results of the analysis provides a theoretical basis for the navigation system of linear channel design and compensation technology.(3) In view of the modern navigation signal through constant envelope modulation will still receive bandpass analog nonlinear effect emission channel effect of the problem, set up emission channel model of modern navigation signal, transmit signal performance for different pre filter bandwidth, different work conditions indexes are analyzed in detail. The simulation results show that: the relevant loss, with a high power amplifier nonlinear effect caused by the communication channel PN code tracking error can be neglected, and the out of band power loss and carrier tracking jitter performance deteriorated significantly. In the power amplifier efficiency highest working point of traveling wave tube, after the big dipper B1 C signals constant envelope processing through the front-end 32 MHz filter out of band power loss of 1.3d B carrier tracking jitter of up to 2.3 degrees. In the past, on the signal envelope variation measure the lack of this probability distribution information, this paper first put forward the concept of power density spectrum envelope variation, and thus established the relationship in order to nonlinear channel download wave tracking jitter and envelope variations, the simulation results show that the theoretical analysis agree well with the numerical simulation results.(4) According to the generation system power and strictly limited resources and the characteristics of high precision linear channel design requirements on satellite signals, proposes a combined table amplitude probability distribution and high power amplifier characteristic item based indexing technique, simulation results show that: in the given 512×32 bit table resource condition in the highest efficiency of power amplifier the work point of traveling wave tube, using the joint list index lookup table Pre-distortion technique, the big dipper B1 C signal band power loss is reduced from 1.3d B to 0.6d B, the carrier tracking jitter from 2.3 degree into 0.2 degrees, compared with equal interval index lookup table method to achieve the same effect saves 81.5% hardware resources. Finally, the design of a digital Pre-distortion method validation under the laboratory environment, the measured results validate the digital Pre-distortion method.Finally, the research results and engineering applications of the thesis is summarized, and the next step will be to carry out the prospects of the work. The research results can be applied to our own satellite navigation system transceiver channel design and high-end receiver research fields.