Method for separating transmitted signals in a radar system

• US 8,884,811 B2
• Filed: 01/30/2012
• Issued: 11/11/2014
• Est. Priority Date: 01/31/2011
• Status: Active Grant

• Current Assignee: Karlsruher Institut Fur Technologie
• Original Assignee: Karlsruher Institut Fur Technologie
• Inventors: Zwick, Thomas, Sturm, Christian
• Primary Examiner(s): Sotomayor, John B
• Application Number:
  US13/361,038
• Publication Number:
  US 20130342387A1
• Time in Patent Office: 1,016 Days
• Field of Search: 342/59, 342/159, 342/202
• US Class Current: 342/59
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/347 using more than one modulation frequency

Abstract

The present invention relates to a method for separating transmitted signals in radar systems and an associated radar system. In the method, the signals for transmission are shared among multiple subcarriers by means of OFDM, which subcarriers are assigned to the transmitting antennas according to a distribution scheme. In this distribution scheme, each subcarrier is assigned to one transmitting antennas only. The subcarriers assigned to a given transmitting antenna are spread over the entire signal bandwidth. In this way, very high dynamics may be achieved while retaining complete orthogonality of the signal paths.

Claims

1. A method for separating transmitted signals in a radar system that includes multiple transmitting antennas with individual transmitted signals and one or several receiving antennas for radar signals, in which the radar signals are transmitted with a signal bandwidth via the individual transmitting antennas in such manner that received radar signals can be assigned to the transmitting antennas by which they were transmitted,

wherein the transmitted signals are shared among multiple subcarriers by means of OFDM, which subcarriers are assigned to the transmitting antennas according to a distribution scheme in which each subcarrier is assigned to one transmitting antenna only and in which the subcarriers assigned to each transmitting antenna are spread over the entire signal bandwidth.

2. The method according to claim 1,

wherein the distribution scheme is switched in fixed or variable periods.

3. The method according to claim 2,

wherein the distribution scheme is switched in such a manner that a cyclical permutation of the assignment of subcarriers to the transmitting antennas is achieved, so that each subcarrier has been transmitted by each transmitting antenna by the end of a fixed number of time steps.

4. The method according to claim 1,

wherein in the case of radar systems in which multiple transmitting devices are each located together with one or several transmitting antennas on separate platforms, transmitting frequencies of the individual transmitting devices are synchronised either by highly accurate clocks or by a common reference, so that the orthogonality of the subcarriers transmitted by the different transmitting devices can be assured.

9. The method according to claim 3,

wherein in the case of radar systems in which multiple transmitting devices are each located together with one or several transmitting antennas on separate platforms, transmitting frequencies of the individual transmitting devices are synchronised either by highly accurate clocks or by a common reference, so that the orthogonality of the subcarriers transmitted by the different transmitting devices can be assured.

5. A radar system comprising at least one transmitting device for radar signals, multiple transmitting antennas, at least one receiving device for radar signals, and one or several receiving antennas,

in which the transmitting device is designed in such manner that it transmits the radar signals with a signal bandwidth via the individual transmitting antennas in such manner that received radar signals can be assigned to the transmitting antennas by which they were transmitted in the receiving device,

wherein the transmitting device is designed such that it shares the transmitted signals among multiple subcarriers by means of OFDM, and assigns the subcarriers to the transmitting antennas according to a distribution scheme in which each subcarrier is assigned to one transmitting antenna only and in which the subcarriers assigned to each transmitting antenna are spread over the entire signal bandwidth, and that the receiving device is designed such that it assigns the received radar signals to the transmitting antennas by which they were transmitted on the basis of the subcarriers received and the distribution scheme.

6. The radar system according to claim 5,

wherein the transmitting device is designed in such manner that it changes the distribution scheme cyclically so that cyclical permutation of the assignment of the subcarriers to the transmitting antennas is achieved, such that each subcarrier has been transmitted by each transmitting antenna after a fixed number of time steps.

7. The radar system according to claim 5,

wherein multiple transmitting devices are each located together with one or more transmitting antennas on separate platforms, wherein transmitting frequencies of the individual transmitting devices are synchronised either by highly accurate clocks or by a common reference, so that the orthogonality of the subcarriers transmitted by the different transmitting devices can be assured.

8. The radar system according to claim 6,

wherein multiple transmitting devices are each located together with one or more transmitting antennas on separate platforms, wherein transmitting frequencies of the individual transmitting devices are synchronised either by highly accurate clocks or by a common reference, so that the orthogonality of the subcarriers transmitted by the different transmitting devices can be assured.