Aircraft traffic alert and collision avoidance device
US5157615A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1991 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Dec 31, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/933
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A passive aircraft Traffic alert and Collision Avoidance Device (TCAD) is based on sensing and responding to transponder replies of other aircraft to SSR interrogations. In order to avoid masking other aircraft replies by the host transponder TCAD repeatedly and randomly suppresses the host transponder and simultaneoulsly listens for other aircraft replies. Suppression on each occasion is effective for an equal and predetermined duration which is much longer than a typical replay, in a preferred embodiment the suppression/listen duration is 725 .mu.s. In this embodiment the time between successive suppression/listen occasions is random between 725 .mu.s. and 5.025 ms. with an average value of about 2.9 ms. Digital signal processing is used to detect and discard garbled or overlapping replies. Each valid reply, exhibiting a minimum pulse amplitude, is decoded and correlated with a calibrated range parameter and given a time tag. Successive replies which match to within predetermined criteria in time and calibrated range are merged to track the positional relation between the host and other aircraft. The positional relation between other aircraft and the host are evaluated via a prio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.