Vehicle position determination system and method

• US 5,375,059 A
• Filed: 02/18/1993
• Issued: 12/20/1994
• Est. Priority Date: 02/05/1990
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Gudat, Adam J., Kyrtsos, Christos T., Stafford, Darrell E., Christensen, Dana A., Friedrich, Douglas W.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/019,542
• Time in Patent Office: 670 Days
• Field of Search: 364/443, 364/449, 364/455, 364/459, 342/357, 342/358, 342/450, 342/451, 342/457, 73/178 R
• US Class Current: 701/215
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B62D 1/28 non-mechanical , e.g. following a line or other known markers
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/52 Determining velocity
• CPC Class Codes: G01S 5/009 Transmission of differential positioning data to mobile
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles

Abstract

Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle'"'"'s position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.

Claims

1. A system for determining the position of a user using orbiting satellites of a global positioning system and a reference station, the system comprising:

(a) first means for computing respective first positions of the satellites in view of a reference antenna at the reference station using previous ephemeris data and responsively determining respective predicted estimated pseudoranges (O_ij);

(b) second means for computing respective second positions of the satellites in view of said reference antenna at the reference station using current ephemeris data and responsively determining respective current estimated pseudoranges (N_ij);

(c) third means responsive to said first and second means, said third means for receiving said respective predicted estimated pseudoranges (O_ij) and said respective current estimated pseudoranges (N_ij), comparing said predicted estimated pseudoranges (O_ij) and said respective current estimated pseudoranges (N_ij), and responsively determining if said current ephemeris data is corrupt;

(d) fourth means responsive to said third means, said fourth means for computing a spatial bias using said current ephemeris data if said current ephemeris data is not corrupt and computing a spatial bias using said previous ephemeris data if said current ephemeris data is corrupt;

(e) fifth means located at the user, for receiving signals from said satellites and said spatial bias and responsively determining an estimate of the position of the user.

2. A method for determining the position of a user using orbiting satellites of a global positioning system and a reference station, the method comprising the steps of:

(1) computing respective predicted estimated pseudoranges (O_ij) of the satellites in view of a reference antenna at the reference station using previous ephemeris data;

(2) computing current estimated pseudoranges (N_ij) of the satellites using current ephemeris data;

(3) comparing said predicted estimated pseudoranges and said current estimated pseudoranges and responsively determining if said ephemeris data is corrupt;

(4) computing a spatial bias using said current ephemeris data if said current ephemeris data is not corrupt and computing a spatial bias using said previous ephemeris data if said current ephemeris data is corrupt; and

(5) receiving, at the user, signals from the satellites and said spatial bias and responsively determining an estimate of the position of the user.