Range-gated radar motion detector
US6239736A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1999 |
| Grant date | May 29, 2001 |
| Priority date | — |
| Expiry date | Oct 29, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/18
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A motion detector combines an FCC approved homodyne pulsed range-gated radar ("RGR") detector (10) and a PIR detector (158). Narrow microwave pulses are transmitted at a predetermined pulse repetition frequency ("PRF") and the pulses are reflected by a target. The RGR detector senses the presence of moving human sized objects within predetermined ranges. Moving objects beyond the ranges are not sensed. The RGR detector employs a pulsed microwave oscillator (12) that is triggered by a system clock (14) and immediately retriggered after a 3 to 100 nanosecond delay (20). The duration of each pulse is 3 to 20 nanoseconds with a half-sine envelope shape. The RGR employs a homodyne detector (36) and shares an antenna (38) with the transmitter. The receiver range is determined by the delay imposed between the transmitted pulses, the first being a transmitted pulse and the second being a local oscillator pulse. Each received 5.8 GHz pulse is mixed down to a baseband by the homodyne detector. The detected baseband signal is amplified, processed, and filted to frequencies below 100 Hz. If the output exceeds a predetermined threshold, an alarm condition is indicated. The threshold is adjustab…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.