Positioning system for a motor vehicle having a satellite receiver

• US 6,240,368 B1
• Filed: 07/12/1999
• Issued: 05/29/2001
• Est. Priority Date: 11/02/1996
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Kreft, Peter
• Primary Examiner(s): Zanelli, Michael J.
• Application Number:
  US09/297,547
• Time in Patent Office: 687 Days
• Field of Search: 701/208, 701/213, 701/214, 701/209, 701/210, 701/216, 701/220, 342/357.06, 342/357.08, 342/357.13, 342/357.14
• US Class Current: 701/214
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G01S 19/53 Determining attitude
• CPC Class Codes: G01S 3/52 using a receiving antenna moving, or appearing to move, in a cyclic path to produce a Doppler variation of frequency of the received signal

Abstract

In a positioning system for a motor vehicle having a satellite receiver, a direction vector subject to error is determined from the received satellite signals. The direction vector subject to error forms an angular range of the direction of travel including a main path and optionally secondary paths of a digitized road map. To determine the actual direction of travel of the motor vehicle, the main path and optionally the secondary paths are pursued, and the path having the best match with the direction vector of the angular range of direction is prioritized. The direction vector is determined from the change in frequency of the received satellite frequencies by the Doppler method.

Claims

1. A positioning system for a motor vehicle, comprising:

a computer;

a satellite receiver in communication with the computer and for receiving a signal from at least one of a GPS satellite and a GLONASS satellite, the satellite receiver calculating from the received signal a direction of travel of the motor vehicle subject to a tolerance represented by an angular range of the direction of travel for an assumed position of the motor vehicle;

a path sensor in communication with the computer; and

means for communication with the computer and for providing a digital road map, wherein;

the computer determines an actual direction of travel at the assumed position of the motor vehicle,

the computer determines, in a subregion of the digital road map containing a plurality of roads, a main path intended to include an instantaneous position of the motor vehicle,

the computer determines as an alternative a plurality of secondary paths intended to include the instantaneous position of the motor vehicle,

a direction of the main path is compared with the angular range, the angular range including a direction of travel of the satellite receiver,

the angular range is prioritized so that only those of the main path and the plurality of secondary paths having respective directions occurring within the angular range receive further consideration by the computer, and

the main path is retained if an unclear determination occurs due an occurrence of a plurality of parallel paths within a narrow network of roads.

2. The positioning system according to claim 1, wherein:

the satellite receiver receives a plurality of satellite signal frequencies while the motor vehicle is traveling, and

the satellite receiver determines the direction of travel of the motor vehicle by performing a Doppler operation on the basis of a change in a frequency of the plurality of satellite signal frequencies.

3. The positioning system according to claim 1, wherein:

the path sensor includes one of a direction sensor and a rotational rate sensor,

a direction finding is provided by the path sensor,

the satellite receiver provides an instantaneous direction vector corresponding to a directional value, and

the direction finding is related to the directional value by being one of superimposed on the directional value and corrected by the directional value.

4. The positioning system according to claim 3, wherein the direction sensor includes a gyro sensor.

5. The positioning system according to claim 1, wherein a size of the angular range is determined by a system error of at least one of the satellite receiver and the positioning system.

6. The positioning system according to claim 1, wherein the computer determines a direction vector for each one of the main path and the plurality of secondary paths at a location of the assumed position of the motor vehicle.

7. The positioning system according to claim 1, wherein the computer:

weights the main path and the plurality of secondary paths, and

determines as a new main path a path having a direction that most closely matches that of the angular range at a location of the assumed position of the motor vehicle.

8. The positioning system according to claim 1, wherein the computer:

compares the direction of travel at a location of the assumed position of the motor vehicle with a path of each road in the subregion of the digital road map, and

determines a new main path as the path having the closest match with respect to the direction of travel.