The invention provides an
underwater quantum distance measurement method based on starry sea light
quantum link transmission. The method comprises the following steps: firstly, establishing a light
quantum communication link by utilizing an aiming tracking technology, generating pump light through a
laser on a
satellite, enabling the pump light to enter a periodically poled
potassium titanyl
phosphate crystal, carrying out spontaneous parametric down-conversion to obtain
signal light and idle light with entanglement characteristics, and respectively transmitting the
signal light and the idle light to a sea surface
station 1 and a sea surface
station 2; using single-
photon detectors of the two sea surface stations to receiving photons; secondly, enabling the sea surface
station 1 to sink, enabling the sea surface station 2 to float on the sea surface, and tracking the position of the sea surface station 1; then, using a single-
photon detector on the sea surface station 1 to emit photons to a target, and receiving the photons by the single-
photon detector after the photons are reflected by the target; and finally, performing
coincidence counting is performed on the time pulse sequences output by the single-photon detectors of the two sea surface stations by using a high-speed acquisition circuit, obtaining the
flight time of the
signal light, and further calculating the distance between the sea surface station 1 and the target.