Method for radio direction finding, direction finding system as well as platform

Patent metadata

Field	Value
Publication number	US-11835637-B2
Application number	US-201916680253-A
Country	US
Kind code	B2
Filing date	Nov 11, 2019
Priority date	Dec 12, 2018
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

A method for radio direction finding using a direction finding system having an antenna, a magnetic field sensor and a control unit, the method comprising: receiving a radio frequency signal of at least one emitter via the antenna by the control unit obtaining a received signal; receiving a magnetic measurement value of the magnetic field at the direction finding system via the magnetic field sensor; correcting the magnetic measurement value obtaining a corrected magnetic measurement value; correcting the received signal obtaining a corrected signal; and determining the precise bearing of the emitter based on the corrected received signal and the corrected magnetic measurement value. Further, a direction finding system and a platform are disclosed.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for radio direction finding using a direction finding system for a platform having at least one antenna, at least one magnetic field sensor and a control unit electrically connected to the at least one magnetic field sensor and to the at least one antenna, the method comprising:
receiving, by the control unit as a received signal via the antenna, at least one radio frequency signal emitted from at least one emitter;
receiving, by the control unit, a magnetic measurement value of the magnetic field at the direction finding system via the magnetic field sensor;
correcting, via the control unit, the magnetic measurement value in order to obtain a corrected magnetic measurement value, wherein the corrected magnetic measurement value includes a corrected bearing with respect to a magnetic pole;
correcting, via the control unit, the received signal in order to obtain a corrected received signal, wherein the corrected received signal includes a corrected bearing of the at least one emitter; and
determining a precise bearing of the at least one emitter based on the corrected received signal and the corrected magnetic measurement value.

2. The method according to claim 1 , wherein the magnetic measurement value is corrected by the control unit using a predetermined magnetic correction table having magnetic correction values, wherein the magnetic correction values are based on at least magnetic deviations of the magnetic field surrounding the direction finding system caused by at least one of the platform itself or alignment errors of the magnetic field sensor mounted on the platform.

3. The method according to claim 2 , wherein at least one of the magnetic correction table or an azimuth correction table has been determined prior to operation of the platform.

4. The method according to claim 3 , wherein at least one of the magnetic correction table or the azimuth correction table is determined for the platform individually.

5. The method according to claim 1 , wherein the received signal is corrected by the control unit using a predetermined azimuth correction table having azimuth correction values.

6. The method according to claim 5 , wherein the azimuth correction values depend on at least one of the frequency of the at least one radio frequency signal or the bearing determined using the received signal.

7. The method according to claim 1 , further comprising:
visualizing the precise bearing on a display of the direction finding system;
storing the precise bearing;
further processing the precise bearing;
printing the precise bearing; and
generating an acoustic output using a speaker of the direction finding system representing the precise bearing.

8. The method according to claim 7 , wherein the precise bearing on the display of the direction finding system is visualized using at least one of a GUI or a map.

9. The method according to claim 1 , wherein the platform is a vehicle.

10. A platform having a direction finding system comprising at least one antenna, at least one magnetic field sensor and a control circuit electrically connected to the at least one magnetic field sensor and the at least one antenna, wherein the control circuit is configured to perform the method of claim 1 .

11. The platform according to claim 10 , wherein the control circuit comprises at least one of:
a magnetic correction table having magnetic correction values; or
an azimuth correction table having azimuth correction values,
wherein at least one of the predetermined magnetic correction table or the azimuth correction table are specific to the platform individually.

12. The platform according to claim 10 , wherein the platform is a vehicle.

13. A direction finding system for a platform comprising:
at least one antenna configured to receive at least one radio frequency signal emitted by at least one emitter;
at least one magnetic field sensor configured to generate a magnetic measurement value at a location of the direction finding system; and
a control unit electrically connected to the at least one magnetic field sensor and to the at least one antenna, wherein the control unit includes circuitry configured to:
receive as a received signal via the at least one antenna the at least one radio frequency signal;
receive the magnetic measurement value of the magnetic field at the direction finding system generated by the magnetic field sensor;
correct the magnetic measurement value in order to obtain a corrected magnetic measurement value, wherein the corrected magnetic measurement value comprises a corrected bearing with respect to a magnetic pole;
correct the received signal in order to obtain a corrected signal, wherein the corrected signal comprises a corrected bearing of the at least one emitter; and
determine a precise bearing of the at least one emitter based on the corrected received signal and the corrected magnetic measurement value.

14. The direction finding system according to claim 13 , wherein the magnetic field sensor is a compass.

15. The direction finding system according to claim 13 , wherein the antenna is a directional antenna.

16. The direction finding system according to claim 13 , wherein the direction finding system comprises at least one of a display for visualizing the precise bearing, a speaker for generating an acoustic output representing the precise bearing or a printer for printing the precise bearing.

17. The direction finding system according to claim 13 , wherein the control unit comprises at least one of a magnetic correction table or an azimuth correction table.

18. The direction finding system according to claim 17 , wherein the control unit comprises the azimuth correction table having azimuth correction values, wherein an azimuth correction values are based on at least the influence of the platform on the measurement of the antenna.

19. The direction finding system according to claim 17 , wherein the control unit comprises the magnetic correction table having magnetic correction values, wherein the magnetic correction values are based on at least magnetic deviations of the magnetic field surrounding the direction finding system caused by at least one of the platform itself alignment errors of the magnetic field sensor mounted the platform.

20. The direction finding system according to claim 13 , wherein the platform is a vehicle.

Assignees

• Rohde & Schwarz

Inventors

• Baumeister Andreas

Classifications

• G01S3/10 Primary

  Means for reducing or compensating for quadrantal, site, or like errors · CPC title

• G01S3/046

  Displays or indicators · CPC title

• G01C21/20 Primary

  Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence) · CPC title

• G01S3/023

  Monitoring or calibrating · CPC title

• G01S3/46

  using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems · CPC title