Vehicle location monitoring system

Claim 3

An apparatus as recited in claim 1, further including a display means for displaying the vehicle location coordinates in said first storage means.

Claim 4

An apparatus as recited in claim 1, wherein the vehicle includes a rotational mechanism which rotates in response to vehicle travel, and wherein said distance sensor further comprises a revolution detector providing an output pulse for every predetermined increment rotation of said rotational mechanism and means converting said output pulses into said output signal.

Claim 5

An apparatus as recited in claim 1, wherein said heading sensor includes a magnetic compass located in said vehicle.

Claim 6

An apparatus as recited in claim 1, wherein said distance and said heading sensors are located within said vehicle, and wherein said first and second storage means, said computing means, said comparator means, and said update means are located at a central station, further including a communications means for transmitting the output signals from said distance and heading sensors to said central station.

Claim 7

An apparatus as recited in claim 5, further including a digital computer located at said central station which is controlled by a stored program to provide the operations of said first and second storage means, said computing means, said comparator means, and said update means.

Claim 8

An apparatus as recited in claim 5, further including a display means located at said central station for displaying the vehicle location coordinates in said first storage means.

Claim 11

A method as recited in claim 8, wherein said table is searched in a direction perpendicular to the last-measured vehicle heading.

Claim 12

A method as recited in claim 8, wherein steps (e)-(g) are repeated at periodic intervals.

Claim 13

A vehicle location monitoring system for determining at a central station the locations of a plurality of vehicles within a predetermined area, comprising: a. a plurality of mobile units, each mobile unit being contained in one of the vehicles and each including a distance sensor providing an output signal for every predetermined increment of vehicle travel, and a heading sensor providing an output signal proportional to vehicle heading, b. a multiplexed communications system providing transmission of the distance sensor and heading sensor output signals from each of said mobile units to the central station, c. at the central station, means temporarily storing said distance and heading sensor output signals from said plurality of mobile units, a first means for storing a last-known location for each of said vehicles, means periodically computing a new location for each of said vehicles and storing the new locations in said first storage means, said computing means utilizing the locations previously stored in said first storage means and said distance and heading sensor output signals, second means for storing the locations of drivable surfaces in the area, means for comparing the location of each vehicle in said first storage means with the locations of drivable surfaces in said second storage means, and providing an output when the location of any vehicle does not correspond to a location in said second storage means, and updating means responsive to said output for changing the vehicle in said first storage means to the location of the nearest drivable surface in said second storage means.

Claim 14

A vehicle location monitoring system for determining at a central station the locations of a plurality of vehicles within a predetermined area, comprising: a. a plurality of mobile units, each mobile unit being contained in one of the vehicles and each including a distance sensor providing an output signal for every predetermined increment of vehicle travel, and a heading sensor providing an output signal proportional to vehicle heading, b. a multiplexed communications system providing transmission of the distance sensor and heading sensor output signals from each of said mobile units to the central station, c. at the central station, means temporarily storing said distance and heading sensor output signals from said plurality of mobile units, a first means for storing a last-known location for each of said vehicles, means periodically computing a new location for each of said vehicles and storing the new locations in said first storage means, said computing means utilizing the locations previously stored in said first storage means and said distance and heading sensor output signals, second means for storing the locations of drivable surfaces in the area, means for comparing the location of each vehicle in said first storage means with the locations of drivable surfaces in said second storage means, and providing an output when the location of any vehicle does not correspond to a location in said second storage means, and updating means responsive to said output for changing the vehicle in said first storage means to the location of the nearest drivable surface in said second storage means.

Claim 15

A vehicle location monitoring as recited in claim 11, further including a display means at the central station which is interconnected with said first storage means for selectively displaying the locations of said plurality of vehicles.

Claim 16

A vehicle location monitoring system as recited in claim 11, wherein said multiplexed communications system includes, at the central station, a master clock providing a plurality of clock pulses, means coupled to said master clock for periodically providing a synchronization pulse to establish a reporting cycle, means transmitting said synchronization pulse to said plurality of mobile units and a demultiplexing means having said clock pulses and synchronization pulses applied thereto for establishing a plurality of successive reporting intervals during each reporting cycle to recognize the distance and heading output signals of each of said mobile units; at each of said mobile units, a multiplexing means responsive to said synchronization pulse for transmitting said distance and heading output signals to the cental station during a reporting interval assigned to the mobile unit.

Claim 17

A vehicle location monitoring system as recited in claim 13, wherein said clock pulses are supplied to said computing means so that a new location is computed for each of said vehicles once each reporting cycle.

Claim 18

A vehicle location monitoring system as recited in claim 11, further including a digital computer operating under control of a stored program to provide the operation of said first and second storage means, said computing means, said comparing means and said updating means.

Claim 19

A vehicle location monitoring system as recited in claim 15, wherein said digital computer includes a memory array functioning as said second storage means, said memory array having a plurality of positions, each position being assigned a coordinate location referenced to said area, and a plurality of data bits stored in said memory array, a data bit being contained in one of said positions only if said assigned coordinate location of said position coincides with the coordinate location of a drivable surface in the area.

Claim 20

A vehicle location monitoring system as recited in claim 16, wherein said updating means includes means searching the positions of said memory array adjacent a position having an assigned coordinate location corresponding to said last-known location stored in said first storage means for each of said vehicles, and means responsive to the detection of a data bit in one of said adjacent positions to change said last-known location in said first storage means to correspond with said coordinate location adjacent said position in said memory array.

Claim 21

A vehicle location monitoring system as recited in claim 17, wherein said searching means searches the positions in said memory array which are located perpendicular to tHe vehicle''s heading stored in said temporary storage means.