Research And Implementation On The Critical Signal Combining Techniques In Multi-Antenna Arraying

The technique of multi-antenna combining is originated from deep space network, bringing a certain combining SNR gain so as to tenuous signal and making full use of existent antennas. Meanwhile, the technique of multi-antenna arraying can keep the mode stable and flexible and play an important part in making up the deficiency of one-antenna receiver. The paper sets a randomly-distributed multi-antenna arraying mode in the Gaussian channel.It analyzes the main solution and key technique of multi-antenna combining and makes a deep research on the signal difference estimation algorithm. It designs multi-antenna signal combining system on the basis of FPGA and DSP. Finally it finishes the realization of four-channel multi-antenna signal synthesizer and testing signal resource. The contents are as follows:1.The paper mainly introduces the application character and trend of development of multi-antenna arraying in deep space. It sets the signal model of randomly-distributed multi-antenna arraying in the Gaussian channel, analyzing the basic principles, key techniques and main signal combining schemes of multi-antenna combining.2. On the basis of carrier frequency and propagation delay skew parameters, it makes a further research on difference evaluation algorithm of signal individuals. First, it analyses the combined evaluation on the basis of carrier frequency and propagation delay skew ambiguous function. Second, making full advantage of multi-antenna signal, the carrier frequency evaluation will transform into monophonic sinusoidal signal frequency evaluation via difference signal. Two fast algorithm based on the sample sequence phase are given and their performance are analyzed. To achieve a perfect trade off between calculated amount and estimation range, combining the steps of coarse search and careful estimation, it will realize the estimation of carrier frequency and propagation delay skew. It has been proved that the accuracy is sufficient for the estimation of propagation delay skew and the theory band is attained in frequency estimation by simulation under NDA3. A more applicable and extensible multi-antenna combing system is designed in the radio architecture of software. On the digital medium frequency platform of FPGA+DSP frame, it divides the system into the modes of multi-speed signal processing, signal parameter estimation and signal difference compensation and combination. Meanwhile, the paper analyses principles of the word length chosen in the view of multilevel fixed points. A algorithm based on word length control on the basis of digit AGC is introduced, which simulation shows the precision of. the algorithm output.4.On the basis of multi-antenna combining system, it conducts four-channel synthesizer hardware solution and implementation. It is mainly composed of FPGA program design module, medium frequency front end process board, numerical AGC module, FPGA and DSP high-speed interface design and exterior display and control module. The design also realizes the multi-channel parameter test-controlled signal source, implementation and hardware regarding to the test. Then it tests the synthesizer under the condition of signal source and actual signal and the verify of combining performance shows the hardware could approach theory value.