Range sensing system

• Main Author: DORRINGTON ADRIAN A
• Format: Patent
• Language: English
• Published: 26.07.2007
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; GYROSCOPIC INSTRUMENTS; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; MEASURING DISTANCES, LEVELS OR BEARINGS; NAVIGATION; PHOTOGRAMMETRY OR VIDEOGRAMMETRY; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; SURVEYING; TESTING

The invention relates to a solid-state range sensing system. As with previous solid-state range sensing systems, an energy source is activated and deactivated in a cyclic pattern with a selected source frequency. A receiver is adapted to sense the reflection of emitted energy from the target. The receiver includes a shielding system to block the sensing of the reflected energy from the target in a cyclic pattern with a selected receiver frequency. Unlike the prior art, the frequency of the source and receiver are offset by a small frequency. The resulting output signal of the receiver is a further cyclic pattern beat signal of frequency equal to the difference between the source activation and receiver shielding modulation frequencies. The best signal is effectively a down-converted version of the source modulation frequency and, unlike the prior art, is compared with a reference beat signal whereby the phase difference between the two beat signals is used to determine a range value. The use of beat signals provides higher precision than the prior art.