Range Estimation Method in a Short-Range FMCW Sonar

We propose a range estimation method for a short-range frequency-modulated continuous wave (FMCW) sonar. Due to the slower sound wave and the greater Doppler effect of the FMCW sonar, the beat frequency of the FMCW sonar cannot keep the constant duration unlike the beat frequency of the FMCW radar. To cope with the drawback of the FMCW sonar, in the proposed method the rising edge and the falling edge of the beat frequency are utilized. This leads us to normally estimate the range of a high-speed underwater vehicle in short-range situation. Simulation results show that the proposed method can estimate the range from the measurements where the Doppler effect is exactly reflected according to the maneuver scenario of high-speed underwater vehicles.