Research On Resolving Ability Of Coherent Mimo Radar

MIMO radar is a new type radar that transmits diverse probing signals via multiple antennas and receives the echoes synchronously by multiple antennas for combined processing. Unlike the conventional radars, this new type one can obtain more comprehensive and essential information from the being probed. Some researches demonstrate that the MIMO Radar has great capability to improve the radar performance of target detection, tracking, recognition and parameter estimation. In addition, the transmit beam pattern design and the bistatic configuration provide more flexibility to adapt the battlefield requirement. Normally, there are two forms of MIMO radar which are classified according to their diversity pattern and antennas configuration. One is the Statistical MIMO radar, the other is the coherent MIMO radar. This thesis focuses on the C-MIMO radar especially the resolving ability and signal processing method. The thesis is organized as follows:First of all, this thesis demonstrates the differences between the C-MIMO radar and the phased array radar. And then, the system model, channel matrix and array pattern are analyzed respectively, in order to explain the principle of signal orthogonality and effective aperture.Secondly, according to structure of separate transmitter and receiver, a bistatic radar model has been established to clear the spatial geometric relationship between targets and antenna arrays. For the purpose of giving some theoretic supports, this thesis has also calculated the ambiguity functions of frequency diversity signal which is used to discuss the resolution affected by AOA and signal parameters.Thirdly, a signal processing method for MIMO radar with frequency diversity signals has been proposed. This method carries out DBF for both receiving angle and transmitting angle on the receiving device, and synchronizes a wideband signal by matched filtering to achieve high resolution in the range dimension. From the simulation results, some basic conclusions about how to realize a high spatial resolution system in an ideal environment have been given.Finally, the echo model of frequency diversity signals in clutter environment has been established with some discussion concerning STAP technology. By comparing the system improvement factor between MIMO radar and phased array, the excellent performance of target detection and the applied potential of miniaturization have been illustrated for the MIMO radar system.