Multi-tasked navigation system and method for an autonomous land based vehicle

• US 5,548,516 A
• Filed: 05/01/1995
• Issued: 08/20/1996
• Est. Priority Date: 12/11/1989
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Sennott, James W., Gudat, Adam J., Shaffer, Gary K., Koehrsen, Craig L., Shin, Dong H., Whittaker, William L., Kemner, Carl A., Devier, Lonnie J., Kyrtsos, Christos T., Lay, Norman K., Peterson, Joel L., Schmidt, Larry E., Kleimenhagen, Karl W., Stafford, Darrell E., Weinbeck, Louis J., Singh, Sanjiv J., Christensen, Dana A., Clow, Richard G., Bradbury, Walter J., Rao, Prithvi N., Shi, Wenfan, West, Jay H., Wu, Baoxin
• Primary Examiner(s): PARK, COLLIN
• Application Number:
  US08/432,247
• Time in Patent Office: 477 Days
• Field of Search: 364/424.01, 364/424.02, 364/443, 364/449, 364/453, 364/454, 364/461, 342/357, 342/455, 342/457, 342/458, 78/178 R
• US Class Current: 701/200
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/931 of land vehicles
• 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 5/009 Transmission of differential positioning data to mobile
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G05D 1/0276 using signals provided by a source external to the vehicle involving a plurality of vehicles G05D1/0287; automatically controlling vehicle speed responsive to externally generated signals B60K31/0058
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS
• CPC Class Codes: G08G 1/202 Dispatching vehicles on the basis of a location, e.g. taxi dispatching

Abstract

A system (400) for positioning and navigating an autonomous vehicle (310) allows the vehicle (310) to travel between locations. Position information (432) is derived from global positioning system satellites (200, 202, 204, and 206) or other sources (624) when the satellites (200, 202, 204, and 206) are not in the view of the vehicle (310). Navigation of the vehicle (310) is obtained using the position information (432), route information (414), obstacle detection and avoidance data (416), and on board vehicle data (908 and 910).

Claims

1. A computer based multi-tasked navigation system for an autonomous land based vehicle comprising:

(1) main task means for coordinating inter-task communications including means for performing high-level decision making;

(2) monitor vehicle task means for reading a communications port to said vehicle including means for reporting vehicle mode changes to said main task means and means for reporting system to vehicle communication state to said main task means, and further including means for writing a vehicle status message to a global memory structure;

(3) scanner task means for providing data from an obstacle detection system to said main task means;

(4) get directives task means for interfacing the system to a host, including means for receiving messages, means for decoding said messages from the host, and means for communicating a received decoded message to a corresponding task means in the system;

(5) message to host task means for interfacing the system to said host, including means for forming messages and means for communicating said messages from the system to said host;

(6) VPS position task means for interfacing a vehicle positioning system to the system, including means for reading output from the vehicle positioning system, checksum means for checking the output for correctness, writing means for putting checked output into a position buffer in a global memory structure, and fault indicating means for sending a message to the main task means whenever a position fault occurs;

(7) VPS posture task means for monitoring the vehicle'"'"'s position while the vehicle is tracking, including means for maintaining a plurality of postures in a posture buffer of the global memory structure; and

(8) tracker task means for calculating steer and speed corrections for said vehicle, including means for reading position information from the position buffer of the global memory structure, means for reading posture information from the posture buffer of the global memory structure, and means for sending said steer and speed corrections to the vehicle to control the vehicle'"'"'s course.

2. A computer-implemented method of operating a multi-tasked navigation system for an autonomous land based vehicle, comprising the steps of:

(1) coordinating inter-task communications including performing high-level decision making;

(2) reading a communications port to said vehicle;

(3) reporting vehicle mode changes to a main task;

(4) reporting system-to-vehicle communication state to said main task;

(5) writing a vehicle status message to a global memory structure;

(6) providing data from an obstacle detection system to said main task;

(7) interfacing the system to a host by receiving and decoding messages from the host, and communicating a received and decoded message to a corresponding task in the system;

(8) interfacing the system to said host by forming and communicating messages from the system to said host;

(9) interfacing a vehicle positioning system to the system by reading output from the vehicle positioning system, checksum checking the output for correctness, writing checked output into a position buffer in a global memory structure, and fault indicating by sending a message to the main task whenever a position fault occurs;

(10) monitoring the vehicle'"'"'s position while the vehicle is tracking by maintaining a plurality of postures in a posture buffer of the global memory structure; and

(11) calculating steer and speed corrections for said vehicle by reading position information from the position buffer of the global memory structure, reading posture information from the posture buffer of the global memory structure, and calculating and sending said steer and speed corrections to the vehicle to control the vehicle'"'"'s course.