Abstract: A deceiving signal detection system includes a first antenna, a second antenna, and a signal processor. The first antenna is configured to receive at least four radio wave signals. The signal processor determines that the radio wave signals are the deceiving signals by determining that a relative positional relation between the first antenna and the second antenna calculated on a basis of the radio wave signals deviates from an actual relative positional relation between the first antenna and the second antenna by more than a predetermined amount, and also determines whether an orientation of the aircraft determined based on positions of the first antenna and the second antenna matches an orientation of the aircraft calculated based on an inertial navigation system.

Abstract: An aircraft position measurement system is provided for an aircraft configured to use an artificial satellite configured to fly in a known orbit. The aircraft position measurement system includes a reflector, a distance-angle measuring member, a satellite position obtainer, and an aircraft position calculator. The reflector configured to be mounted on the artificial satellite and reflect an electromagnetic wave in a direction in which the electromagnetic wave arrives. The distance-angle measuring member is configured to be mounted on the aircraft and emit an electromagnetic wave and measure a bearing and a distance to the artificial satellite when seen from the aircraft. The satellite position obtainer is configured to obtain an absolute position of the artificial satellite. The aircraft position calculator is configured to calculate a position of the aircraft based on the absolute position of the artificial satellite and the bearing and the distance to the artificial satellite.

Abstract: A navigation system includes a receiver and a signal processor. The receiver is mounted on a second aircraft. The second aircraft is an acquisition target of location information. The receiver is configured to receive a navigation signal from each of three or more first aircrafts. The navigation signal includes the location information on a location of the corresponding first aircraft. The navigation signal is transmitted as a radio signal from a navigation apparatus mounted on each of the three or more first aircrafts. The signal processor is mounted on the second aircraft. The signal processor is configured to calculate a location of the second aircraft on the basis of the navigation signal.

Abstract: There is provided a navigation system, comprising: a buoy on a water surface movably anchored to a bottom; a plurality of at least three transmitters fixed to the bottom or at different positions in the water for transmitting signals to specify the positions; a receiver, being disposed with the buoy, configured to receive signals transmitted by the plurality of transmitters; a signal processor, being disposed with the buoy, configured to specify the position of the buoy, based on the signals received by the receiver, and generate a navigation signal indicating the position of the buoy, and a radio, being disposed with the buoy, configured to transmit the navigation signal generated in the signal processor wirelessly, the navigation signal being receivable by a radio in a mobile body.

Abstract: An aircraft position measurement system is provided for an aircraft configured to use an artificial satellite configured to fly in a known orbit. The aircraft position measurement system includes a reflector, a distance-angle measuring member, a satellite position obtainer, and an aircraft position calculator. The reflector configured to be mounted on the artificial satellite and reflect an electromagnetic wave in a direction in which the electromagnetic wave arrives. The distance-angle measuring member is configured to be mounted on the aircraft and emit an electromagnetic wave and measure a bearing and a distance to the artificial satellite when seen from the aircraft. The satellite position obtainer is configured to obtain an absolute position of the artificial satellite. The aircraft position calculator is configured to calculate a position of the aircraft based on the absolute position of the artificial satellite and the bearing and the distance to the artificial satellite.

Abstract: A navigation system includes a receiver and a signal processor. The receiver is mounted on a second aircraft. The second aircraft is an acquisition target of location information. The receiver is configured to receive a navigation signal from each of three or more first aircrafts. The navigation signal includes the location information on a location of the corresponding first aircraft. The navigation signal is transmitted as a radio signal from a navigation apparatus mounted on each of the three or more first aircrafts. The signal processor is mounted on the second aircraft. The signal processor is configured to calculate a location of the second aircraft on the basis of the navigation signal.

Abstract: A deceiving signal detection system includes a first antenna, a second antenna, and a signal processor. The first antenna is configured to receive four or more multiple navigation signals. Each of the multiple navigation signals indicates a transmitting position and a transmitting time of the each navigation signal. The second antenna is configured to receive the multiple navigation signals. The signal processor is configured to determine whether four or more multiple radio wave signals that are received by the first antenna and the second antenna and each signal indicate a transmitting position and a transmitting time of the signal are the multiple navigation signals or deceiving signals.

Abstract: There is provided a navigation system, comprising: a buoy on a water surface movably anchored to a bottom; a plurality of at least three transmitters fixed to the bottom or at different positions in the water for transmitting signals to specify the positions; a receiver, being disposed with the buoy, configured to receive signals transmitted by the plurality of transmitters; a signal processor, being disposed with the buoy, configured to specify the position of the buoy, based on the signals received by the receiver, and generate a navigation signal indicating the position of the buoy, and a radio, being disposed with the buoy, configured to transmit the navigation signal generated in the signal processor wirelessly, the navigation signal being receivable by a radio in a mobile body.