초록 ▼

A method and apparatus for radio position determination is provided including an unknown position transmitter for transmitting a radio wave having compensation for multipath, a plurality of base repeaters having a synchronized pulse for time reference, for receiving the radio wave emitted by the unk

A method and apparatus for radio position determination is provided including an unknown position transmitter for transmitting a radio wave having compensation for multipath, a plurality of base repeaters having a synchronized pulse for time reference, for receiving the radio wave emitted by the unknown position transmitter and for determining the relative times-of-arrival of the radio wave with respect to the synchronized pulse, and a central monitoring station coupled to the base repeaters for computing from the locations of the base repeaters and from the measured times-of-arrival, a coarse-position fix of the unknown-position transmitter. The system may include a mobile reference transceiver located within the coarse-position fix, for transmitting a reference signal, wherein the central monitoring station generates a differential position from the reference signal and the radio wave for guiding the mobile reference transceiver to the unknown position transmitter.

대표청구항 ▼

A method of radio position determination of an unknown position transmitter using a mobile-reference transceiver and a plurality of base repeater generating a slave grid synchronization pulse for time reference, located at known geographic locations in a geographic area and coupled to a central moni

A method of radio position determination of an unknown position transmitter using a mobile-reference transceiver and a plurality of base repeater generating a slave grid synchronization pulse for time reference, located at known geographic locations in a geographic area and coupled to a central monitoring station generating a master grid synchronization pulse for time reference, comprising the steps of: emitting by the unknown position transmitter located within the geographical area, a radio wave having modulation compensation for multipath which also serves as a coarse ranging modulation, and a modulated carrier with an identification code; receiving by at least three base repeaters the radio wave emitted by the unknown position transmitter and measuring at the base repeaters the relative times-of-arrival of the radio wave with respect to the master grid synchronization pulse for deriving ranging times and therefore ranges from said base repeaters to said unknown position transmitter; computing from the locations of said base repeaters and the measured times-of-arrival, hyperbolic lines of position for the unknown position transmitter; computing a coarse-position fix of the unknown position transmitter from the hyperbolic lines of position using a least means squares algorithm; dispatching a search team having a mobile reference transceiver to the coarse-position fix of said unknown-position transmitter; transmitting from said mobile reference transceiver located within the coarse-position fix a reference signal having modulation compensation for multipath which also serves as a coarse ranging modulation; receiving by the base repeaters the reference signal emitted by said mobile reference transceiver and computing a difference between the reference signal and the radio wave, for deriving a differential position vector from said mobile reference transceiver to said unknown position transmitter; guiding the mobile reference transceiver to said unknown position transmitter using the differential position vector; emitting a polling message by said mobile reference transceiver; emitting, in response to receiving the polling message, a reply message by said unknown position transmitter; independently computing from the polling message and the reply message a local-time-of-flight and therefore the local range from the mobile reference transceiver to the unknown position transmitter; and emitting an audible sound by said unknown position transmitter for assisting in locating the unknown position transmitter.