| 摘要 |
An object dection device comprises at least two sensors (17), each adapted to transmit and receive signals, and a processor (3) to control operation of the sensors. Each sensor comprises a transmit pulse generator (5) operating at a first transmit pulse repetition frequency and a receive pulse generator (10) operating at a second, different, pulse repetition frequency. A timing control signal from the processor switches the sensors between transmit/receive mode and recive only mode. A first sensor (1) operates in transmit /receive mode, the first sensor transmitting at a first pulse repetition frequency and receiving reflections of the transmitted signal, reflected off an object; wherein the reflections are mixed with a reference signal to produce an intermediate frequency (IF) signal and analysed to derive a direct range measurement. The or each other sensor (2 .. n) operates in receive only mode to produce an indirect range measurement and the receiver pulse generator operates at a second pulse repetition frequency. The operation is repeated for the or each other sensor (2 .. n) operating in transmit/receive mode such that a set of direct and indirect measurements are obtained, whereby a linear distance (12) from the object is derived from the direct and indirect range measurements. The device is particularly applicable to use as a parking aid.
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