System for automatic vehicle location

Claim 3

The system of claim 1 wherein said dead reckoning means comprises: reference detection means for generating a direction signal indicative of the direction of travel of said mobile unit as said mobile unit passes said last communicating remote unit; said direction signal being further stored by said storage means; relative heading sensor means, cooperating with said reference detection means, for generating a signal indicative of the instantaneous heading of said mobile unit relative to said direction; odometer means, for generating a signal indicative of the distance traveled by said mobile unit from said last communicating remote unit; and conversion means, responsive to said distance signal, said relative heading signal and said reset signal, for resettably generating a first output signal indicative of the component in said direction of the vectorial position of said mobile unit with respect to the location of said last communicating remote unit, and a second output signal indicative of the component in a direction perpendicular to said direction of the vertical position of said mobile unit with respect to the location of said last communicating remote unit, said conversion means output signals being reset in response to changes in said stored information.

Claim 4

The system of claim 2 wherein said relative heading sensor means comprises a digital change means in heading sensor, said change means in heading sensor generating a pulse indicative of a predetermined quantum of change in heading by said mobile unit and a counter, responsive to said change in heading pulses and said reset signal, for generating a heading count indicative of cumulative changes in heading of said mobile unit since said counter was last reset, said counter being reset in response to changes in said stored information.

Claim 5

The system of claim 3 wherein said predetermined quantum of change is 90°.

Claim 6

The system of claim 3 wherein said predetermined area contains a plurality of intersecting drivable surfaces, said remote units are respectively positioned proximate to said drivable surfaces to communicate thereby with said mobile unit as said mobile unit passes said remote unit on said drivable surfaces, and a remote unit is positioned at each substantially non-perpendicular intersection of said drivable surfaces, wherein further: said dead reckoning means comprises: a turn sensor, coupled to said mobile unit, for generating output signals respectively indicative of perpendicular turns in left and right hand directions by said mobile unit; and heading register means, responsive to said turn sensor output signals, for generating a two bit binary count indicative of changes in the heading of said mobile unit in increments of 90°, said count being incremented in response to each turn in one of said directions, decremented in response to each turn in the other of said directions; and said conversion means comprises: first and second counters, and gating means, responsive to said binary heading count and said distance signal, for selectively incrementing or decrementing the contents of said first and second counters in accordance with said heading count and said distance signal, whereby the contents of said first register is representative of the position of said mobile unit from said stored location in said original direction and the contents of said second register are representative of the position of said mobile unit from said stored location in a direction perpendicular to said original direction; said heading register means, and said first and second counters being responsive to said reset signal and reset in response to each change in said stored information.

Claim 7

The system of claim 5, wherein said mobile unit is coupled to a vehicle having longitudinal and transverse axes, and said reference detection means comprises: a first antenna having a radiation pattern disposed to communicate with remote units positioned on one transverse side of said vehicle; a second antenna having a radiation pattern disposed to communicate with remote units positioned on a second transverse side of said vehicle, said second side being opposite said first side; and detector means, coupled to said first and second antennas, for generating a signal indicative of which said first and second antennas communicate with said remote unit, said detector means signal being indicative of said direction, and applied to said storage means.

Claim 8

The system of claim 1, wherein: said dead reckoning means comprises: absolute heading sensor means for producing an output signal indicative of the heading of said mobile unit with respect to a fixed reference direction; odometer means, for generating a signal indicative of the distance traveled by said mobile unit; conversion means, responsive to said heading signals, signals, said distance signals and said reset signal, for resettably generating a first output signal indicative of the component of the vectorial position of said mobile unit with respect to the location of said stored location in said reference direction and a second output signal indicative of the component of the vectorial location of said mobile unit with respect to said stored location in a direction perpendicular to said reference direction; said conversion means output signals being reset in response to changes in said stored location.

Claim 11

The method of claim 8, further including the step of: (g) generating and storing information indicative of the initial direction of travel of said mobile unit with respect to said respective remote units at the time said mobile unit comes into the vicinity of said respective remote units; and wherein said dead reckoning step (c) comprises the steps of: (h) generating a signal indicative of the heading of said mobile unit with respect to said initial direction of travel; (i) generating a signal indicative of increments of distance traveled by said mobile unit; (j) generating, from said heading signal and said distance signal, first and second signals respectively indicative of the component of the instantaneous vectorial location of said mobile unit with respect to said stored location in a direction substantially parallel to said initial direction and of the component of the vectorial location of said mobile unit with respect to said stored location in a direction substantially perpendicular to said initial direction.

Claim 12

The method of claim 9 for a predetermined area containing intersecting drivable surfaces, wherein said positioning step (a) includes the following step of: (k) positioning a remote unit at each non-perpendicular intersection of said drivable surfaces; and wherein further: said generation of a heading signal step (h) includes the steps of: (l) generating signals respectively indicative of perpendicular turns by said mobile unit in right and left directions; and (m) incrementing and decrementing a resettable two-bit bidirectional counter in response to said turn signals to generate said heading signal.