Research On Multiple Dimensional Parameter Estimation For Complicated Spatial Signal

Wave propagation may cause reflection and scattering phenomenon, makes thespacial signal environment become complicated, the channel model can't be describedappropriately using the traditional point source model, whereas distributed source modelis needed. According to the roughness of the reflection or scattering surface, distributedsource can be classified into coherently distributed (CD) source and incoherentlydistributed (ICD) source. Up till now, numerous spatial distributed source models andcorresponding direction of arrival (DOA) estimation algorithms were proposed.However, most of the existing algorithms need multiple dimensional searches, thecomputation burden is heavy. What's more, a model which describes the coexistence ofmultiple types of sources and corresponding parameter estimation algorithm is not seenyet. This dissertation studied the two types of distributed source deeply, thecorresponding parameter estimation algorithm is proposed. Based on this, the signalmodel which describes the coexistence of multiple types of sources and correspondingparameter estimation algorithm is proposed. The main contributions of this dissertationare as follow.1. The Gaussian approximation model for coherently distributed source is studied.According to the approximation model for CD source, we know that, in thecircumstance of small angular spread, the angular spread mainly affects theamplitude of the general steering vector (GSV). We can extract the phaseinformation of the GSV to estimate the DOA of CD source, and estimate the angularspread of CD source from the amplitude information of the GSV. The correspondingalgorithms which based on cumulants, matrix pencil and twice virtual interpolationsmethod were proposed. According to the character of the cumulants that the arraysensors can be spread, we can realize the parameter estimation of multiple signalswith quite little sensors. The method based on matrix pencil used the character thatthe phase information of the GSV can be extracted from the received data, thusDOA for CD source can be estimated effectively. The method based on twice virtualinterpolations can improve the precision of the interpolation, thus improve the estimation precision of the parameters of CD sources.2. The spatial frequency model for incoherently distributed source is studied.According to the model, when the angular spread is small, the angular spread mainlyaffects the amplitude of the elements of the covariance matrix. We can estimate theDOA of incoherently distributed source from the phase of the elements of thecovariance matrix, and estimate the angular spread from the amplitude of theelements of the covariance matrix. Thus the DOA and angular spread estimationmethod for incoherently distributed source is proposed based on the reconstruct ofthe covariance matrix. This method can realize the separable estimation of DOA andangular spread for incoherently distributed source. When estimating the DOA, thealgorithms were proposed based on least square fitting and MUSIC-like algorithm,respectively. By designation of the spatial 3D array structure, the MUSIC-likealgorithm is extended to the 2D-DOA for incoherently distributed source.3. The composite signal model which describes the coexistence of point source,coherently distributed source and incoherently distributed source is proposed.According to the affection of the angular spread to the coherently distributed sourceand incoherently distributed source, the blind identification and DOA estimationmethod for composite source is proposed. The method can identify the sources andseparate each source effectively, based on this, by using MUSIC-like method ormatching pursuit method, the corresponding DOA for each source can be estimatedeffectively.4. The estimation of multiple dimensional parameters for signal sources in presence ofscattering is studied. According to the distributed source signal model, the multipledimensional parameters estimation method for the estimation of Doppler frequency,azimuth and elevation is proposed based on PRO-ESPRIT. This method can extractthe Doppler frequency information from the signal by using time delay of the arraysignal, thus we can estimate the azimuth and elevation of coherently distributedsource from the phase information of the GSV.