Radar system having interleaved serial transmitting and parallel receiving

• US 10,823,836 B2
• Filed: 11/08/2016
• Issued: 11/03/2020
• Est. Priority Date: 11/19/2015
• Status: Active Grant

• Current Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Wintermantel, Markus
• Primary Examiner(s): Moore, Whitney
• Application Number:
  US15/776,217
• Publication Number:
  US 20190265347A1
• Time in Patent Office: 1,456 Days
• Field of Search: None
• CPC Class Codes: G01S 13/343 using sawtooth modulation
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing
• CPC Class Codes: H01Q 1/3283 side-mounted antennas, e.g. bumper-mounted, door-mounted mounted on windscreens H01Q1/1271

Abstract

An environmental detection method for a vehicle uses transmitting antennas to emit transmission signals that each consist of a sequence of identical or similar single signals, uses receiving antennas to receive the transmission signals reflected from objects, and processes the received signals. The transmission signals are emitted from only one transmitting antenna at a time, and the active transmitting antenna alternates cyclically from single signal to signal. All receiving antennas are always used in parallel. The received single signals are accumulated in proper phase for the different combinations of transmitting and receiving antennas to at least one relative speed hypothesis of objects. Digital beam formation is performed based on the accumulated signal values, each belonging to the same relative speed hypothesis, from different antenna combinations. Phase differences between received signals from different transmitting antennas are thereby taken into consideration.

Claims

1. A method for the environmental detection of a motor vehicle, comprising the following steps:

emitting transmission signals using NS≥

2 transmitting antennas, wherein in each case, the considered transmission signals consist of a sequence of N identical or similar single signals,

receiving transmission signals reflected off objects using NE>

=2 receiving antennas, and

processing the received signals,

wherein

in each case, transmitting is done on only one of the NS transmitting antennas, wherein from single signal to single signal, the transmitting antenna used alternates cyclically, and within each of the NP=N/NS periods of the cyclical transmitting antenna alternation, the temporal progression is at least approximately the same, and

in order to receive single signals reflected off objects, all considered NE receiving antennas are always used in parallel,

characterized in that

each of the NP received single signals are accumulated in proper phase for the NS×

NE different combinations of transmitting and receiving antennas to plural relative speed hypotheses of objects,

by way of said NS×

NE accumulated values, each belonging to the same relative speed hypothesis, from different combinations of transmitting and receiving antennas, a digital beam formation is performed, and those phase differences are thereby taken into consideration, which arise between the receiving signals to the different transmitting antennas due to their temporal offset because of the cyclical transmitting antenna alternation, and which depend on the respective relative speed hypothesis,

the considered NS×

NP transmission signals are located at least approximately in a temporally equidistant raster,

each of the NP received single signals are added up in proper phase for the NS×

NE different combinations of transmitting and receiving antennas by way of a Discrete Fourier Transform (DFT), wherein each of the frequency supporting points of the DFT corresponds to a group of equidistant relative speed hypotheses,

a digital beam formation is performed by way of the NS×

NE DFT values of a respective frequency supporting point multiple times with different phase differences, since there are various hypotheses for the phase differences between the receiving signals to the different transmitting antennas for each frequency supporting point NS, which hypotheses can be distinguished in the limited phase unambiguity range of 360°

, wherein these different phase difference hypotheses correspond to different subgroups of the relative speed hypotheses of this frequency supporting point,

wherein that one of the different phase difference hypotheses of a DFT frequency supporting point is selected for which the result of the digital beam formation best fits the hypothesis of an individual point-shaped object, or

wherein that one of the different phase difference hypotheses of a DFT frequency supporting point is selected which has the largest maximum in the result of the digital beam formation, or

wherein the correct one of the different phase difference hypotheses is determined in that the assigned different relative speed hypotheses are compared with the change in the measured distance of the object and/or respectively or with the already known relative speed of the object, over two or more measuring cycles, or

wherein the distance of the individual transmission signals varies from measuring cycle to measuring cycle and in which the correct one of the different phase difference hypotheses is determined in that the assigned different varying relative speed hypotheses are compared with each other over two measuring cycles.

2. The method according to claim 1, in which only the selected phase difference hypothesis of a DFT frequency supporting point and the assigned subgroup of relative speed hypotheses are further considered.

3. The method according to claim 1, in which

the frequency of the emitted single signals is modulated linearly,

each of the NP received single signals for the NS×

NE different combinations of transmitting and receiving antennas is sampled in an equidistant raster NA-times and a first DFT is formed by way of these NA sampled values, and

a second DFT is determined for each frequency supporting point of this first DFT via each of the NP receiving signals, wherein each frequency supporting point of the second DFT corresponds to a group of equidistant relative speed hypotheses.

4. The method according to claim 1, in which there are NS>

=2 groups of, in each case, NG>

=2 transmitting antennas which are simultaneously operated and modulated with respect to each other with regard to signals, which transmitting antennas are separated by receiving signals originating from various simultaneously operated transmitting antennas by demodulation and the digital beam formation is performed over NG×

NS×

NE antenna combinations.

5. A radar system for the environmental detection of a motor vehicle, using the method according to claim 1, wherein said system comprises

transmitting means for emitting transmission signals using NS≥

2 transmitting antennas, receiving means for receiving transmission signals reflected off objects using NE>

=2 receiving antennas, and

signal processing means for processing the received signals,

wherein

in each case only one of the NS transmitting antennas is ready to transmit, wherein from single signal to single signal, the transmitting antenna used can in particular be alternated cyclically and within each of the NP=N/NS periods of the cyclical transmitting antenna alternation, the temporal progression is at least approximately identical,

the NE receiving antennas can be used for the parallel reception of single signals reflected off objects,

characterized in that

the NP received single signals in each case for the NS×

NE different combinations of transmitting and receiving antennas can be accumulated in proper phase to plural relative speed hypotheses of objects, and

by way of said NS×

NE accumulated values, each belonging to the same relative speed hypothesis, from different combinations of transmitting and receiving antennas, a digital beam formation can be performed, and those phase differences can thereby be taken into consideration, which arise between the receiving signals to the different transmitting antennas due to their temporal offset because of the cyclical transmitting antenna alternation, and which depend on the respective relative speed hypothesis,

wherein the signal processing means are configured to execute said method.