VEHICLE NAVIGATION SYSTEM

• US 3,749,893 A
• Filed: 12/22/1971
• Issued: 07/31/1973
• Est. Priority Date: 12/22/1971
• Status: Expired due to Term

• Current Assignee: Dale Hileman
• Original Assignee: Dale Hileman
• Inventors: Hileman, Dale
• Primary Examiner(s): Botz, Eugene G.
• Assistant Examiner(s): Smith, Jerry
• Application Number:
  US05/210,804
• Time in Patent Office: 587 Days
• Field of Search: 235/150.2,150.26,150.27,189,197 340/24,73 346/8,13 307/236 343/11R,112C,112PT
• US Class Current: 701/300
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G06F 7/548 Trigonometric functions; Co-ordinate transformations

Abstract

A system for continually updating the Cartesian coordinates of a land vehicle on a map or graph, employing: a compass and shaft encoder for continually producing a heading code; and a pulse generator coupled to the vehicle drive system to continually produce a train of pulses representing distance traveled. A digital resolver effectively multiplies the train of pulses by the sine and cosine of compass heading to produce two trains of pulses representing vector components of the distance traveled in a Cartesian coordinate system. These two trains are continually integrated by mechanical plotting means operated by reversible motors receiving the two trains. Encoders may be coupled to the mechanical plotting means to derive, in digital form, coordinates which may be transmitted by radio to a remote location for plotting.

Claims

1. In a system for tracking a land vehicle on a display system using Cartesian coordinates, the combination of a compass and means responsive to said compass for providing heading data directly in digital form of said vehicle, a pulse generator coupled directly to the drive system of said vehicle to continually produce a group of pulses representing a unit distance traveled, digital computing means for resolving said group of pulses into X and Y trains of pulses by continually multiplying said group of pulses from said pulse generator by a function of said compass heading data, thereby producing said X and Y trains of pulses proportional to the vector components of the distance traveled by said vehicle for plotting in a Cartesian coordinate system, and means for seperateLy integrating said X and Y trains of pulses, thereby continually updating Cartesian coordinate data.

2. A system for continually updating the Cartesian coordinates of a land vehicle from a starting point in a given geographic area as said vehicle travels through said area, comprised of means for continually producing a heading code in digital form corresponding to the heading of said vehicle, said code having two sign bits A and B, where said bit A is a positive sign for any northerly heading from 270* to 90*, and a negative sign for any southerly heading from 90* to 270*, and said bit B is a positive sign for any easterly heading from 0* to 180*, and a negative sign for any westerly heading from 180* to 0*, and where said code includes a plurality of additional bits, C, D . . . for designating:

a number of successive equally spaced headings from 0* to 90* with successively increasing code numbers, an equal number of equally spaced headings from 90* to 180* with successively decreasing code numbers, and a duplication of successively increasing and then decreasing code numbers from 180* through 270* to 0*, means for continually generating pulses representing distance traveled by said vehicle, digital means responsive to said heading code and to said pulses for producing two pulse trains of pulses approximately according to the equations Delta X Delta D sin theta Delta Y Delta D cos theta where theta is the heading angle represented by said code bits C, D . . . , Delta D is the number of pulses produced by said pulse generating means in an increment of time, and Delta X and Delta Y are the number of pulses resolved into said two trains during said increment of time, means responsive to said heading code bit B for integrating said Delta X pulses to provide a number of integrated Delta X pulses equal to the product Delta D sin theta by effectively adding Delta X pulses when said code bit B is positive, and subtracting Delta X pulses when said code bit B is negative, and means responsive to said heading code bit A for integrating said Delta Y pulses to provide a number of integrated Delta Y pulses equal to the product Delta D cos theta by effectively adding Delta Y pulses when said code bit A is positive, and subtracting Delta Y pulses when said code bit A is negative.

3. A system as defined in claim 2 wherein said last two named means each includes a bidirectional integrating device for adding pulses of one polarity and subtracting pulses of opposite polarity, and a junction transistor having its base connected to receive pulses to be integrated of a given polarity, its collector connected to receive one of said sign bits A and B directly, and its emitter connected to receive the complement of one of said bits A and B through a resistor, and means for coupling said bidirectional integrating device to said emitter, whereby said transistor functions as a noninverting coupler for pulses to be integrated when said one of said sign bits is of a given polarity and an inverting coupler for pulses to be integrated when said one of said sign bits is of a polarity opposite said given polarity.

4. Apparatus as defined in claim 3 wherein said digital means for producing said trains of pulses Delta X and Delta Y includes decoding means responsive to said code bits C, D . . . representing the heading angle theta for producing codes representing the values of sin theta and cos theta , and pulse rate multiplying means for producing from said pulses Delta D said train of pulses Delta X and Delta Y as products of said pulses Delta D and said codes representing values of sIn theta and cos theta .

5. In a system for tracking a vehicle using linear coordinates, the combination of a compass and means for providing heading data of said vehicle directly in digital form from said compass, a pulse generator coupled to a drive train of said vehicle to directly produce a train of pulses representing distance traveled, digital computing means for resolving said train of pulses into two trains of pulses by multiplying said train of pulses from the pulse generating means by a function of said compass heading data, thereby producing said two trains of pulses representing vector components of the distance traveled in a linear coordinate system, and means for separately counting or integrating said two trains of pulses, thereby producing said linear coordinates.

6. Apparatus, for continually updating Cartesian coordinates of a land vehicle from a starting point in a given geographic area as said vehicle changes its position in said area, comprised of a rotating magnetic-compass means for producing a sinusoidal signal which crosses zero, from a voltage of a given polarity with respect to a reference, once per revolution at a predetermined point in the revolution in relation to magnetic north, code means operated in synchronism with said magnetic-compass means for producing a cyclic heading code having one code cycle per revolution of said compass means, the output of said cyclic code means always being zero when said rotating compass means is at a predetermined point in the direction of travel of said vehicle, whereby said heading code always corresponds to the heading of said vehicle relative to said magnetic north direction when said sinusoidal signal crosses zero from a voltage of said given polarity, means for detecting when said sinusoidal signal crosses zero from a voltage of said given polarity, buffer storage means for receiving and storing a heading code from said code means under control of said detecting means when said sinusoidal signal crosses zero from a voltage of said given polarity, means for continually producing pulses of a number proportional to distance traveled by said vehicle, means for resolving said pulses into two trains of pulses approximately according to the equations Delta X Delta D sin theta Delta Y Delta D cos theta where theta is the heading angle represented by said code, Delta D is the number of pulses produced by said pulse generating means in an increment of time, and Delta X and Delta Y are the numbers of pulses resolved into said two trains during said increment of time, and means for integrating separate said two trains of pulses Delta X and Delta Y thereby continually updating said Cartesian coordinates.

7. Apparatus as defined in claim 6 wherein said code means comprises a shaft encoder driven in synchronism with said compass means for producing a heading code in digital form corresponding to the heading of said vehicle, said code having two sign bits A and B, where said bit A is a positive sign for any northerly heading from 270* to 90*, and a negative sign for any southerly heading from 90* to 270*, and said bit B is a positive sign for any easterly heading from 0* to 180*, and a negative sign for any westerly heading from 180* to 0*, and where said code includes a plurality of additional bits C, D, . . . for designating:

a number of successive equally spaced headings from 0* to 90* with successively increasing code numbers, an equal number of equally spaced headings from 90* to 180* with successively decreasing code numbers, and a duplication of successively increasing and then decreasing code numbers from 180* through 270* to 0*, and wherein said resolving means is comprised of digital means responsive to said heading code and to said pulses for producing two pulse trains of pulses approximately according to the equations Delta X Delta D sin theta Delta Y Delta D cos theta where theta is the heading angle represented by said code bits C, D . . . , Delta D the number of pulses produced by said pulse generating means in an increment of time, and Delta X and Delta Y are the number of pulses resolved into said two trains during said increment of time, and means responsive to said heading code bits A and B for integrating said Y and X pulses in positive and negative directions according to the signs represented by said code bits A and B.

8. Apparatus as defined in claim 7 wherein said last named means includes for each of said trains of Delta X and Delta Y pulses a bidirectional integrating device for adding pulses of one polarity and subtracting pulses of opposite polarity, and a junction transistor having its base connected to receive pulses to be integrated of a given polarity, its collector connected to receive one of said sign bits A and B directly, and its emitter connected to receive the complement of one of said bits A and B through a resistor, and means for coupling said bidirectional integrating device to said emitter, whereby said transistor junctions as a noninverting coupler for pulses to be integrated when said one of said sign bits is of a given polarity opposite said given polarity.

9. Apparatus as defined in claim 8 wherein said digital means for producing said trains of pulses Delta X and Delta Y includes decoding means responsive to said code bits C, D . . . representing the heading angle theta for producing codes representing the values of sin theta and cos theta , and pulse rate multiplying means for producing from said pulses Delta D said train of pulses Delta X and Delta Y as products of said pulses D and said codes representing values of sin theta and cos theta .

10. Apparatus as defined in claim 6 where said means for integrating said trains of pulses Delta X and Delta Y is comprised of a plotting device having first and second cursors driven in respective X and Y directions with means for plotting carried at the intersection of said cursors, each of said cursors being driven by two drive chains, one at each end, each drive chain going around two pulley at least one of which is driven, said cursors being adjustable in angle relative to X and Y axis of said plotting device through said drive chains to compensate for any deviations of east-west and north-south plots from positions parallel to said X and Y axes, respectively, by offsetting said cursors in respective directions opposite any deviations from positions parallel to said X and Y axes after a single magnet has been adjusted in said magnetic compass means to compensate for magnetic compass error due to ferromagnetic mass of said vehicle by so positioning said magnet in said magnetic compass means as to cause parallel lines to be plotted on east and west and parallel lines to be plotted on north and south headings.

11. In a system for continually plotting Cartesian coordinates of a moving vehicle using:

an X-Y plotting device having two crossed cursors which carry a stylus at the intersection thereof, a magnetic compass for producing a heading signal, means for obtaining a signal representing distance traveled by said vehicle, and a resolver for obtaining from said heading and distance signals two signals according to the equations Delta X Delta D sin theta Delta Y Delta D cos theta where Delta D is an increment of distance traveled, theta is the angle represented by said heading signal, and Delta X and Delta Y are said two signals employed separately to drive said two cursors in X and Y directions of said plotting device, a method for compensating compass error due to the ferromagnetic mass of said vehicle by adjusting the position of compensating magnetic means near said magnetic compass such that, when said vehicle travels in a rectangle on cardinal magnetic headings, a rhomboid is plotted, and adjusting said cursors in said plotting device at angles with respect to X and Y axes thereof equal but opposite in direction to angles by which corresponding sides of said rhomboid depart from lines parallel to said X and Y axes.