| 摘要 |
A combined portable monitoring, tracking and searching system, comprising one or more monitored and/or searched units (MSU) and one or more monitoring and searching units (SRU), wherein the MSU comprises processing means, memory means, display and/or audio means, a transmitting/receiving antenna, a spread spectrum receiver to receive modulated spread spectrum data and to convert it to baseband data, a spread spectrum transmitter, a data spreader, a synthesizer or frequency generator, and a correlator to correlate spread spectrum data received by said spread spectrum receiver with a known Pseudo Noise (PN) sequence; and, the SRU comprises processing means, memory means display and/or audio means, a transmitting/receiving omnidirectional antenna, a transmitting/receiving directional antenna, a spread spectrum receiver to receive modulated spread spectrum data and to convert it to baseband data, a spread spectrum transmitter, a data spreader, a synthesizer unit or frequency generator, a correlator to correlate spread spectrum data received by said spread spectrum receiver with a known PN sequence, and delay measurement means, to measure the time elapsed from the beginning of a first transmitted sequence to the beginning of one or more of the sequences received from a MSU in response to said first transmitted sequence. |
