{
  "$type": "site.standard.document",
  "description": "A method/system of detecting if a relay is present in a vehicle PEPS system, including transmitting from antenna(s) of a vehicle, a first/second LF signals and determining a minimum time-gap between the signal transmissions so that the time-gap exceeds the channel-coherence-time of a high-frequency…",
  "path": "/patents/1331977",
  "publishedAt": "2022-11-24T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B60R25/246",
    "ROBERT BOSCH (AUSTRALIA) PTY LTD"
  ],
  "textContent": "A method/system of detecting if a relay is present in a vehicle PEPS system, including transmitting from antenna(s) of a vehicle, a first/second LF signals and determining a minimum time-gap between the signal transmissions so that the time-gap exceeds the channel-coherence-time of a high-frequency wireless-relay. A maximum time between the signals is determined by a timing requirement of the PEPS system and the maximum allowable change in a key-fob position. A time gap between the minimum/maximum times is determined. Depending on the time-gap, the system timing requirement is increased to provide a predetermined-time. At the predetermined-time, separately transmitting between the first/second LF signals, which have a known signal ratio, from a vehicle antenna to a key-fob as part of an LF challenge; measuring, at the key-fob, the signal-levels of the first/second LF signals; and determining if the ratio of the first/second LF signals are within a predefined range.",
  "title": "METHOD AND SYSTEM FOR RELAY ATTACK PREVENTION INCORPORATING CHANNEL COHERENCE"
}