Patent ID: 6346878
Filing Date: 2002-02-12
Classification: G01S,G07C

Abstract:
Apparatus for determining a distance between first and second objects, comprising:an interrogation signal generator situated on the first object for generating and transmitting an interrogation signal; an interrogation signal receiver for receiving the interrogation signal and a response signal generator for generating and transmitting in response to reception of the interrogation signal, a response signal that is substantially congruent to said interrogation signal, delayed by a signal processing duration of said response signal generator, both the interrogation signal receiver and the response signal generator being situated on the second object; a response signal receiver situated on the first object, for receiving the response signal; a signal delay unit situated on the first object, to which signal delay unit the generated interrogation signal is fed in parallel with an interrogation signal transmission unit, and which signal delay unit forwards the said interrogation signal, delayed by a time duration that corresponds to the signal processing duration of the response signal generator, for comparison with the received response signal; and an evaluation unit which compares the delayed interrogation signal forwarded by the signal delay unit with the received response signal, and determines the distance between the first and second objects by determining a distance-indicative phase difference between the delayed interrogation signal forwarded by the signal delay unit and the transmitted response signal.