Method of operating a multi-antenna pulsed radar system

• US 6,184,819 B1
• Filed: 07/06/1999
• Issued: 02/06/2001
• Est. Priority Date: 07/03/1998
• Status: Expired due to Term

• Current Assignee: ADC GmbH (TE Connectivity Limited)
• Original Assignee: Automotive Distance
• Inventors: Adomat, Rolf, Waibel, Franz
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/348,605
• Time in Patent Office: 581 Days
• Field of Search: 342/70, 342/71, 342/72, 342/107, 342/109, 342/113, 342/114, 342/115, 342/127, 342/128, 342/133, 342/135, 342/139, 342/140, 342/146, 342/155
• US Class Current: 342/127
• CPC Class Codes: G01S 13/48 using multiple beams at emission or reception
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons

Abstract

A method for operating a radar system using at least two antennas provides an increased angular resolution for determining the angular position, radial velocity, and/or distance to a reflection object. A plurality of successive measuring phases are carried out in at least one measuring process. In each measuring phase, operation is repeatedly switched between a transmitting operation in which a transmitted signal pulse is emitted, and a receiving operation in which reflection signals are detected as received signals in the pulse pause interval between successive transmitted pulses. In at least one measuring phase, two different neighboring antennas of the radar system are used respectively as the transmitting antenna for emitting the transmitted signal and as the receiving antenna for detecting the reflected signal. In this manner, the respective receiving antenna monitors only the angular range of overlap between the emitted beam of the transmitting antenna and the field of view of the receiving antenna. The information provided by the detected signals in this overlapping angular range achieves an increased angular resolution. The method is particularly suitable for operating a separation distance warning system for a motor vehicle.

Claims

1. A method of operating a radar system including at least two antennas respectively directed to monitor respective different angular ranges in an area to be monitored, for determining at least one of a distance, angular position and radial velocity of a reflection object located in said area to be monitored, said method comprising carrying out at least one measuring process including a plurality of measuring phases, wherein:

each said measuring phase comprises plural alternating transmitting operations and receiving operations;

each said transmitting operation comprises emitting, from a transmitting antenna selected among said at least two antennas, a respective transmitted signal pulse having a pulse duration (t_ON);

each said receiving operation comprises activating a receiving antenna selected among said at least two antennas to be able to receive at least one of any reflection signals that may be reflected from said reflection object and incident on said receiving antenna during a respective pulse pause interval having a pause duration (t_OFF) between successive ones of said transmitted signal pulses;

in at least one of said measuring phases, the same selected one of said at least two antennas is used as said transmitting antenna in said transmitting operations and as said receiving antenna in said receiving operations; and

in at least another of said measuring phases, two different selected ones of said at least two antennas are respectively used as said transmitting antenna in said transmitting operations and as said receiving antenna in said receiving operations.

2. The method according to claim 1, wherein:

said at least two antennas are directed so that at least some of said respective different angular ranges partially overlap one another; and

in said another of said measuring phases, said two different ones of said antennas respectively monitor said respective different angular ranges that partially overlap one another.

3. The method according to claim 2, wherein, in said another of said measuring phases, said receiving antenna receives reflection signals reflected from said reflection object only if said reflection object is at least partially located in an overlapping angular range in which said different angular ranges partially overlap one another.

4. The method according to claim 2, wherein said two different ones of said antennas in said another of said measuring phases are physically arranged adjacent to each other.

5. The method according to claim 1, wherein said two different ones of said antennas in said another of said measuring phases are physically arranged adjacent to each other.

6. The method according to claim 1, wherein said radar system further includes an antenna selector switch adapted to be selectively switchably connected independently to said at least two antennas, and wherein said receiving antenna and said transmitting antenna are respectively selected from among said at least two antennas by correspondingly switching said antenna selector switch.

7. The method according to claim 6, wherein said switching of said antenna selector switch is carried out within 5 ns.

8. The method according to claim 6, wherein said radar system further includes a control unit connected for control signal transmission to said antenna selector switch, and wherein said switching of said antenna selector switch is carried out responsive to control signals provided by said control unit.

9. The method according to claim 6, wherein said radar system further includes a transmit-receive switch connected to said antenna selector switch and a local oscillator switch selectively connectable with said transmit-receive switch, wherein said method further comprises repeatedly switching between said transmitting and receiving operations by repeatedly synchronously switching said transmit-receive switch and said local oscillator switch between a transmit position and a receive position, wherein said antenna selector switch remains connected to said same selected one of said at least two antennas during said transmitting and receiving operations in said at least one of said measuring phases, and wherein said antenna selector switch is repeatedly switched between said two different ones of said at least two antennas in synchronism with said repeated switching of said transmit-receive switch and said local oscillator switch to switch between said transmitting and receiving operations in said at least another of said measuring phases.

10. The method according to claim 1, wherein said different angular ranges comprise different azimuth angular ranges.

11. The method according to claim 1, wherein said different angular ranges comprise different azimuth angular ranges and different elevation angular ranges.

12. The method according to claim 1, wherein:

said at least two antennas include first and second antennas that respectively transmit and receive signals in respective first and second ones of said different angular ranges, which partially overlap each other in a first overlapping angular range;

in a first one of said measuring phases, said first antenna is used as said transmitting antenna in said transmitting operations and as said receiving antenna in said receiving operations;

in a second one of said measuring phases, said second antenna is used as said transmitting antenna in said transmitting operations and as said receiving antenna in said receiving operations;

in a third one of said measuring phases, said first antenna is used as said transmitting antenna in said transmitting operations and said second antenna is used as said receiving antenna in said receiving operations; and

said first, second and third measuring phases can be carried out in any order relative to each other.

13. The method according to claim 12, wherein:

said at least two antennas further include a third antenna that transmits and receives signals in a third one of said different angular ranges, which partially overlaps said second different angular range in a second overlapping angular range;

in a fourth one of said measuring phases, said third antenna is used as said transmitting antenna in said transmitting operations and as said receiving antenna in said receiving operations;

in a fifth one of said measuring phases, one of said second and third antennas is used as said transmitting antenna in said transmitting operations and the other of said second and third antennas is used as said receiving antenna in said receiving operations; and

said first, second, third, fourth and fifth measuring phases can be carried out in any order relative to each other.

14. The method according to claim 12, further comprising evaluating said at least one reflection signal received respectively in each one of said measuring phases to determine at least said angular position of said reflection object.

15. A radar system comprising:

a plurality of antennas that each respectively have different angular fields of view and that are arranged so that said fields of view partially overlap one another;

an antenna selector switch that is selectively switchably connectable to each one of said antennas independently;

a signal mixer;

a transmit-receive switch permanently connected to said antenna selector switch;

an oscillator;

a local oscillator switch permanently connected to said oscillator;

a signal processing unit connected to an output of said signal mixer; and

a control unit connected for control signal transmission to said antenna selector switch, said transmit-receive switch, and said local oscillator switch;

wherein;

said transmit-receive switch is selectively switchably connectable to said mixer and to said local oscillator switch independently;

said local oscillator switch is selectively switchably connectable to said mixer and to said transmit-receive switch independently; and

said control unit is so arranged, configured and adapted so that it causes said transmit-receive switch and said local oscillator switch respectively to switch cyclically and synchronously between being connected to each other and being connected to said mixer, and synchronously therewith causes said antenna selector switch to switch cyclically between being connected to a first one of said antennas and being connected to a second one of said antennas.