| 摘要 |
PROBLEM TO BE SOLVED: To provide a new technique for grasping the direction of movement of an underwater mobile entity.SOLUTION: A measurement device 2000 is provided in an underwater mobile entity 4000. An electromagnetic wave receiving unit 2020 receives, in the water, an electromagnetic signal outputted on a first frequency from a signal output device 3000. An acoustic receiving unit 2040 receives, in the water, an acoustic signal outputted on a second frequency from the signal output device 3000. A frequency calculation unit 2050 calculates the frequencies of the electromagnetic signal received by the electromagnetic wave receiving unit 2020 and the acoustic signal received by the acoustic receiving unit 2040. A relative speed calculation unit 2060 calculates a relative speed of the underwater mobile entity 4000 to the signal output device 3000 on the basis of a relationship of the first and second frequencies and the frequencies of the electromagnetic wave signal and the acoustic signal calculated by the frequency calculation unit 2050. |
