MIMO Radar Beamforming And Code

With the development of multiple-input multiple-output (MIMO) communication system, the concept of multiple-input multiple-output radar is also proposed by people and is becoming a hot studying area. MIMO radar is based on the array signal processing technology. The transmit antenna array transmits independent or orthogonal signals (time domain, frequency domain, code domain), the receive antenna array receives the echo signals. Although some old radar systems can be attributed to the domain of MIMO radar, but the concept of the MIMO radar still has the significance. It not only includes the previous some different radar systems, but also offer a unified signal model and system which makes people's awareness to a new level. On transmitter end, the MIMO radar transmits independent coded waveforms ominidirectionally, on receiver end, a bank of matched filters are used to separate the echo signals corresponding to the different transmit codes. The digital beamforming (DBF) is then employed to form both receive and effective transmit beams. Then a virtual array with large aperture is formed. This is superior to the traditional radar and is one of the key properties of MIMO radar. In this paper, we discuss the complete complementary codes construction methods. The code have low sidelobes in some range. We also discuss the beamforming algorithms using stepped-frequency signal, spread-spectrum signal, complete complementary codes.In order to increase the range resolution while increasing the angular resolution, the aperture of the virtual array may be larger than the range resolution, then the antenna array becomes a wide band array. In this paper we discuss the wide band array signal processing and show that long time coherent integration can improve the performance of target separation.