| High Frequency Surface Wave Radar(HFSWR),a new type of radar,has a very extensive and profound value in both the civilian field and the military field,for its flexibility and over-the-horizon detection capability.At present,shipborne HFSWR has been in a deep research and the overall process tends to mature.However,there are still some problems not being fully resolved,such as array error calibration in radar.Radar array calibration exits widely in all kinds of system,especially in HFSWR.The main contribution of my paper are constructing the mathematical modeling of array error,and studying the possible calibration algorithms based the model.The main work of the article is as follows:(1)The main signal processing flow of shipborne HFSWR is studied and the section that may generate array error is also studied based on it.The mathematic model of array error in shipborne HFSWR is established.Then,the influence of four different array error types on shipborne HFSWR signal processing algorithm(clutter suppressing algorithm and super-resolution algorithm)is analyzed and the relevant conclusions are obtained.(2)The array error calibration algorithms based on partly calibrated arrays are studied.The algorithm for channel gains and phases error is realized by using calibrated arrays from the perspective of blind estimation and rotational in variance.The results show that the ESPRIT alrithm with partly calibrated arrays ha s some advantages compared with the blind estimation algorithm with partly calibrated arrays in calibration performance or algorithm compatibility.In addition,an array calibration algorithm based on partly calibrated arrays for simultaneous gains and phases error and mutual error is also studied.Based on the structural characteristics of the Uniform Linear Array(ULA),the algorithm uses the mutual coefficient,a Teoplitz matrx with a certain length,to decouple the mutual error and the gains and phases,thereby achieves the correct position of target.(3)The algorithm of array self-calibration is studied.This algorithm can complete the array error calibration without external information,which is essentially the parameter optimization,and therefore exits a local optimal problem.In this paper,we mainly study the self-calibration algorithm for the channel gains and phases error and the mutual error,respectively,and give the relevant simulation and performance analysis.In addition,we also try to study the algorithm of joint calibration for the gains and phases error and the mutual error and give the simulation and performance analysis.It should be noted that the optimization performance of array self-calibration algorithm is bound by the initial value for that it does not get external information and obtain the optimal value completely through its own iteration.To break this dilemma,either introduce new amounts of information in it,or use biological evolutionary theory.Self-calibration algorithm has some limitations in engineering application,suitalble for fine calibration.(4)The array error calibration algorithm based on Manifold Separation Technique(MST)is studied.The algorithm is essentially an active calibration and it can calibrate array pattern error,compared to other active calibration algorithms.MST seperates the array manifold into the product of a sampling matrix(dependent on the antenna array only)and a Vandermonde structured coefficients vector depending on the wavefileld only.And it has a strong array manifold fit capability.In this paper,several algorithms are proposed,such as the ES-OW algorithm,the ES-OP algorithm and the ES-IMP algorithm.Among them,the ES-OW algorithm has a strong engineering application value and the ES-IMP algorithm surpasses the proposed ES-MUSIC alogirthm with higher stability and accuracy. |
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