Radiobased locating system provided with a synthetic aperture

• US 7,948,431 B2
• Filed: 09/07/2005
• Issued: 05/24/2011
• Est. Priority Date: 01/04/2005
• Status: Active Grant

• Current Assignee: Symeo GmbH (indie Semiconductor, Inc.)
• Original Assignee: Symeo GmbH (indie Semiconductor, Inc.)
• Inventors: Gulden, Peter, Max, Stephan, Vossiek, Martin
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Brainard; Timothy A
• Application Number:
  US11/813,369
• Publication Number:
  US 20100141506A1
• Time in Patent Office: 2,085 Days
• Field of Search: 342/25, 342118-146
• US Class Current: 342/42
• CPC Class Codes: B25J 13/089 Determining the position of the robot with reference to its environment
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G01S 13/9017 with time domain processing of the SAR signals in azimuth G01S13/9005 takes precedence
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined

Abstract

The invention relates to a method for increasing the accuracy of a measurement of a radio-based locating system comprising a mobile station and at least one fixed station, wherein the movement of a mobile station from an initial position is detected by way of measuring data of an absolute sensor system and a relative sensor system, a virtual antenna is embodied in the form of synthetic aperture by way of measuring data and the mobile station is focused on the fixed station and/or vice versa by using the synthetic aperture.

Claims

1. A method for increasing measurement precision of a radio-based position determination system comprising a mobile station and at least one stationary station, the method comprising:

detecting a movement of the mobile station starting from an initial position, the detecting utilizing measurement data of an absolute sensor system and a relative sensor system;

generating a virtual antenna in a form of a synthetic aperture utilizing the measurement data by relative coordinates to a reference point, and focusing either;

a) the mobile station on the stationary station or;

b) the stationary station on the mobile station, the focusing utilizing the synthetic aperture;

wherein the absolute sensor system is generated from at least one secondary radar and at least one transponder; and

wherein either;

c) the mobile station is the secondary radar and the at least one stationary station is the transponder or;

d) the mobile station is the transponder and the at least one stationary station is the secondary radar.

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

utilizing the synthetic aperture via a suitable selection of at least one of a size of the aperture, the amplitude, and phase weighting of the measurement data of the absolute sensor system for generating a direction behavior of the synthetic aperture, such that its direction diagram lies nearly homogeneously in a region of an error ellipse of an arbitrary preceding position measurement.

3. The method according to claim 2, further comprising:

performing an initial rough focusing utilizing a measurement value of at least one of an absolute sensor system and a relative sensor system.

4. The method according to claim 2, further comprising:

performing an initial rough focusing utilizing information of preceding measurements.

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

utilizing the synthetic aperture via a reverse calculation ensuing from a known position of the stationary station to unknown positions of the mobile station, which reverse calculation ensues via a mapping method with synthetic aperture, via a broadband holographic mapping method.

6. The method according to claim 5, wherein:

for reverse calculation of a point b(x, y, z) of a first station, the method further comprising;

correlating a measured acquisition signal E_n(ω

) with a theoretical function F_n(a_n, r, ω

) that a first station would generate at a position r=(x, y, x)^T considered from the measurement point a_n=(x_n, y_n, z_n)^T of the second station.

7. The method according to claim 6, further comprising utilizing a reconstruction rule according to the following equation:

8. The method according to claim 7, wherein an ultimate reconstruction rule is provided as:

9. The method according to claim 1, further comprising:

utilizing the synthetic aperture via a reverse calculation of known positions of the mobile station to an unknown position of the stationary station.

10. The method according to claim 1, further comprising:

calculating distance and angle information between the mobile station and the stationary station.

11. The method according to claim 10, wherein the mobile station is a secondary radar and the stationary station is a transponder.

12. The method according to claim 10, further comprising:

merging, with a Kalman filter for one or more positions, the distance and angle data of one or more mobile stations.

13. The method according to claim 10, further comprising:

executing the stationary stations as passive back-scatter tags; and

providing an absolute position determination according to distance and angle relative to the mobile station.

14. The method according to claim 1, further comprising:

repeating the steps to improve the position determination of the mobile station.

15. A device to increase measurement precision of a radio-based position determination system, comprising:

a mobile station;

at least one stationary station;

an absolute sensor system generated from at least one secondary radar and at least one transponder;

at least one relative sensor system provided for quantification of a magnitude and a direction of a position change of the mobile station relative to an original position;

a signal processing device for common processing of measurement data acquired via the absolute sensor system and the relative sensor system for generation of a virtual antenna in a form of a synthetic aperture, wherein either;

a) the mobile station is the secondary radar and the at least one stationary station is the transponder or;

b) the mobile station is the transponder and the at least one stationary station is the secondary radar; and

a focusing device for focusing one to the other of at least one of;

a) the mobile station on the stationary station and b) the stationary system on the mobile station based on the synthetic aperture.

16. The device according to claim 15, wherein the mobile station is formed by a transponder and the at least one stationary station is formed by a secondary radar.

17. The device according to claim 16, further comprising:

a data transmission device for transfer of data from at least one secondary radar to the signal processing device.

18. The device according to claim 15, further comprising:

a data transmission device for transfer of data from at least one secondary radar to the signal processing device.

19. The device according to claim 15, further comprising:

a Kalman filter for rough prediction of a position value of a stationary station, which rough prediction serves as prior information.

20. The device according to claim 15, wherein the positioning system is an RTOF (round trip time of flight) or a TOA (time of arrival) radio positioning system.