Device for detecting angle of elevation error in a multiple beam radar sensor

• US 6,476,760 B1
• Filed: 10/11/2001
• Issued: 11/05/2002
• Est. Priority Date: 08/10/1999
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schneemann, Jörg, Olbrich, Herbert, Wagner, Klaus-Peter, Winter, Klaus, Eder, Sonja
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US09/807,196
• Time in Patent Office: 390 Days
• Field of Search: 342/59, 342/73-81, 342/104, 342/117, 342/149-158, 342/165-175, 342/195, 342/378-384, 342/70, 342/71, 342/72, 342/27, 342/28, 342/368-377, 370/339
• US Class Current: 342/173
• CPC Class Codes: G01S 13/424 Stacked beam radar
• CPC Class Codes: G01S 13/48 using multiple beams at emission or reception
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/295 Means for transforming co-ordinates or for evaluating data, e.g. using computers
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/4034 in elevation, i.e. in the vertical plane
• CPC Class Codes: G01S 7/4091 during normal radar operation

Abstract

A method and a radar sensor for determining an elevation angle error of a multibeam radar sensor are described. In order to detect an elevation angle of the multibeam radar system with respect to a predefined target, a plurality of laterally arranged cutting planes at a predefined distance are formed. The values of the corresponding antenna diagrams in each plane are stored in a suitable form, for example, normalized and in a parametric form taking into account the elevation angle α. In order to reduce the size of the memory, it is sufficient to store one symmetry half for reasons of symmetry if additional information, for example, road clutter values are added, so that the upward or downward direction of the angle can be recognized. By comparing the measured echo values obtained by normalization and application of a quality factor, a corresponding elevation angle α is obtained for each cutting plane. Using an appropriate histogram, an angle for the maladjustment of radar sensor can be determined from the measured values stored over a longer period of time.

Claims

1. A method of determining an elevation angle error in a multibeam radar sensor, comprising:

directing at least two transmitted beams onto a radar target;

determining and storing comparison values of an antenna diagram in a basic plane in a cutting plane formed by the multibeam radar sensor and the radar target;

comparing reflected received beams of the at least two transmitted beams to the previously determined and stored comparison values for each reflected received beam;

determining an elevation angle from the comparison values;

forming at least one additional, laterally arranged cutting plane at a predefined distance;

determining values for at least one additional reference antenna diagram as a function of the elevation angle;

storing the values for the at least one additional reference antenna diagram in a memory for each additional, laterally arranged cutting plane; and

determining an error angle for the elevation angle from a comparison with the at least one additional reference antenna diagram.

2. The method according to claim 1, further comprising the step of:

storing for the at least one additional reference antenna diagram only values for one symmetry half of the cutting plane formed by the multibeam radar sensor and the radar target and the at least one additional, laterally arranged cutting plane.

3. The method according to claim 1, further comprising the step of:

storing additional information in order to determine a direction of the elevation angle.

4. The method according to claim 3, wherein:

the additional information includes echo signals from a road surface.

5. The method according to claim 1, further comprising the step of:

forming a quality value for the elevation angle from stored values of the basic plane and the at least one additional, laterally arranged cutting plane.

6. The method according to claim 5, further comprising the step of:

outputting the elevation angle with a highest quality on the basis of the quality value.

7. The method according to claim 1, wherein:

angle results from previous measurements are included in a selection.

8. The method according to claim 1, further comprising the step of:

analyzing each elevation angle and associated one of the basic plane and the at least one additional, laterally arranged cutting plane in a histogram.

9. The method according to claim 8, further comprising the steps of:

storing the elevation angle; and

using an absolute value of a mean value of the stored elevation angle as a measure for a maladjustment of the multibeam radar sensor.

10. The method according to claim 8, further comprising the step of:

performing an automatic adjustment of the multibeam radar sensor in accordance with a value of a vertical maladjustment angle.

11. The method according to claim 1, further comprising the step of:

storing the at least one additional reference antenna diagram as a coefficient of a polynomial.

12. The method according to claim 1, further comprising the step of:

when a maladjustment limit value is exceeded, performing at least one of the following steps;

outputting information, and

shutting off the multibeam radar sensor.

13. A radar sensor, comprising:

at least two transmitting/receiving antennas;

a controller for transmitting, receiving, and analyzing echo signals;

an angle output for an elevation angle; and

a memory for storing values of at least one additional antenna diagram of an additional lateral cutting plane, wherein;

the controller determines an error angle for the elevation angle from the stored values, and

the error angle is picked up at the angle output.

14. The radar sensor according to claim 13, wherein:

for symmetric antenna diagrams the memory receives values from one symmetry half of other cutting planes.