High-resolution 2-D sector-scan imaging using MIMO sonar with narrowband LFM pulses

For obtaining high cross-range resolution, a new sector-scan imaging approach based on a multiple-input multiple-output (MIMO) sonar is proposed in this paper. The MIMO sonar is composed of two transmitting sensors and a receiving uniform linear array (ULA), which are located on the same straight line. The spacing between two transmitting sensors is equal to the product of the sensor number and the sensor spacing of the receiving ULA. Furthermore, two narrowband linear frequency modulation (LFM) pulses, sharing the same frequency band but opposite modulation slopes, are employed as transmitting waveforms. In addition, the phase-shifting beam-forming is conducted on the outputs of matched filters. Via theoretical analysis and numerical simulation, it is shown that the MIMO sonar doubles the cross-range resolution, when compared to the traditional 2-D sector-scan sonar.