ULTRASONIC WAVE TRANSMITTING AND RECEIVING DEVICE, METHOD AND PROGRAM

PROBLEM TO BE SOLVED: To improve updating speed of an echo image in comparison to prior art while causing practically none deterioration in reliability of additional information.SOLUTION: In an n-th transmitting and receiving group, a first and second ultrasonic signals FM(H)Tx are transmitted and a first and second echo data items FM(H)Rx and FM(L)Rx are obtained, thereupon a third ultrasonic signal CW(H)Tx is transmitted and a third echo data item CW(H) is obtained. In an n+1-th transmitting and receiving group, a first and second ultrasonic signals FM(H)Tx are transmitted and a first and second echo data items FM(H)Rx and FM(L)Rx are obtained, thereupon a fourth ultrasonic signal CW(L)Rx is transmitted and a fourth echo data item CW(L)Rx is obtained. A high frequency echo image and a low frequency echo image are updated every time from the first and second echo data items FM(H)Rx and FM(L)Rx. The third echo data item CW(H)Rx of the n-th time and the fourth echo data item CW(L)Rx of the n+1-th time are combined to be utilized for bottom sediment determination.