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Monitoring of route and schedule adherence

  • US 5,541,845 A
  • Filed: 08/02/1994
  • Issued: 07/30/1996
  • Est. Priority Date: 08/02/1994
  • Status: Expired due to Term
First Claim
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1. Apparatus for monitoring adherence of a vehicle to a selected vehicle route from a vehicle monitoring station, the apparatus comprising:

  • location determination (LD) means, carried on a selected vehicle, for receiving LD signals from an LD signal source spaced apart from the vehicle and for determining and recording the location coordinates corresponding to a location L(ts) of the vehicle at a selected time t=ts ;

    a computer, carried on the vehicle and communicating with the LD means, having an electronic map of a selected route R, where the selected route is approximated by an ordered sequence {Pk }k of path segments Pk, numbered k=1,2, . . , K (K≧

    2), with path segment Pk'"'"' (1≦

    k'"'"'<

    K) being intersected by path segment Pk'"'"'+1, in at least one point and with each path segment Pk being surrounded by a corridor segment Ck having a width approximately equal to 2dk, measured in a direction approximately perpendicular to a general direction of the segment Pk, where dk is a selected positive distance;

    where the computer determines the perpendicular foot π

    k (L(ts)) of the location L(ts) on at least one of the path segments Pk, determines the distance Dk (L(ts)) from the location L(ts) to the perpendicular foot π

    k (L(ts)), and determines whether the distance Dk (L(ts))≦

    dk for at least one index value k;

    where the computer determines that, when Dk (L(ts))≦

    dk for at least one index value k, the vehicle is adhering to the selected route R; and

    where the computer determines, when Dk (L(ts))>

    dk for all index values k, that the vehicle is not adhering to the route R, and the computer then transmits at least one of (1) a signal indicating that the vehicle is not adhering to the route R and (2) the location coordinates of the vehicle for at least one selected time t=ts'"'"', for which Dk (L(ts'"'"'))>

    dk, to a selected vehicle monitoring station that is spaced apart from the vehicle.

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