Method for the operation of an antenna group having a plurality of transmitters and a plurality of receivers and associated apparatus
The present invention relates to a method for the operation of an antenna group ( 1 ) having M≧2 transmitters and N≧2 receivers ( 3 ) for the digital beamforming. In the method, a coherent transmit signal is transmitted in a transmit-receive-cycle via each of the M transmitters ( 2 ) into an area to be monitored, and a coherent receive signal from the area is recorded by each of the N receivers ( 3 ) for each transmit signal so that M·N receive signals are obtained. To each receive signal, a combination of the respective transmitting transmitter ( 2 ) and the respective receiving receiver ( 3 ) is allocated. The M·N receive signals are processed by means of digital beamforming to obtain spatial information about objects in the area to be monitored. In the method, each of the M·N receive signals is multiplied during processing by an amplitude factor which is individually allocated to the respective combination of transmitter ( 2 ) and receiver ( 3 ), wherein the amplitude factors are selected such that an increase of the signal dynamic range at the digital beamforming is achieved. The method and the apparatus formed for the execution of the method allow a high angle resolution and, at the same time, a high signal dynamic range.
1. A method for the operation of an antenna group ( 1 ) having M≧ 2 transmitters ( 2 ) and N≧2 receivers ( 3 ), in which a coherent transmit signal is transmitted in a transmit-receive-cycle via each of the M transmitters ( 2 ) into an area to be monitored and a coherent receive signal from the area is recorded by each of the N receivers ( 3 ) for each transmit signal, wherein M·N receive signals are obtained, and to each of the receive signals, a combination of the respectively transmitting transmitter ( 2 ) and the respectively receiving receiver ( 3 ) is allocated, and in which the M·N receive signals are processed by means of digital beamforming to obtain spatial information about the objects in the area to be monitored, characterized in that each of the M·N receive signals is multiplied during processing by an amplitude factor, which is individually allocated to the respective combination of transmitter ( 2 ) and receiver ( 3 ), and which causes an increase of a signal dynamic range at the digital beamforming.
2. The method according to claim 1 , characterized in that the allocation of the amplitude factors to the combinations of transmitter ( 2 ) and receiver ( 3 ) takes place on the basis of a mathematical mapping of the antenna group ( 1 ) onto a virtual antenna group having only one virtual transmitter and M·N virtual receivers, which has the same phase relations between the virtual receivers and the virtual transmitter as between the transmitters ( 2 ) and the receivers ( 3 ) of the antenna group ( 1 ), wherein for the virtual antenna group, amplitude factors for an amplitude weighting of its virtual receivers are determined, which for such an antenna group increase the signal dynamic range at the digital beamforming, and these amplitude factors, by means of a revertive mapping onto the antenna group ( 1 ), are then allocated to the combinations of transmitters ( 2 ) and receivers ( 3 ) of this antenna group ( 1 ).
3. The method according to claim 1 or claim 2 , characterized in that the transmit signals, by switching between the transmitters ( 2 ), are transmitted in a chronological sequence via the transmitters ( 2 ).
4. The method according to claim 1 or claim 2 , characterized in that the receivers ( 3 ) for the reception of the receive signal for the transmit signal transmitted by a transmitter ( 2 ) each are switched within a common time window at the same time to reception mode.
5. The method according to claim 1 or claim 2 , characterized in that the amplitude factors are provided in the form of a M×N-matrix, wherein each matrix element is allocated to a different combination of transmitter ( 2 ) and receiver ( 3 ).
6. The method according to claim 1 , characterized in that the transmit signals are transmitted in the microwave range.
7. The method according to claim 1 or claim 2 , characterized in that the antenna group ( 1 ) is used with less than ten transmitters ( 2 ) and less than ten receivers ( 3 ).
8. An apparatus for radar monitoring of an area, comprising at least one antenna group ( 1 ) having M≧2 transmitters ( 2 ) and N≧2 receivers ( 3 ), one transmit and receive device ( 5 ), which transmits a coherent transmit signal in a transmit-receive-cycle via each of the M transmitters ( 2 ) into an area to be monitored, and records from the N receivers ( 3 ) for each transmit signal a receive signal from the area, wherein M·N receive signals are obtained, and to each of the receive signals, a combination of the respectively transmitting transmitter ( 2 ) and the respectively receiving receiver ( 3 ) is allocated, and
a device ( 9 ) for digital beamforming, which processes M·N receive signals by means of digital beamforming, to obtain spatial information about objects in the monitored area, characterized in that the device ( 9 ) for digital beamforming is formed such that it multiplies during processing each of the M·N receive signals by an amplitude factor, which is individually allocated to the respective combination of transmitter ( 2 ) and receiver ( 3 ).
9. The apparatus according to claim 8 , characterized in that the amplitude factors are stored in the apparatus in the form of a M×N-matrix, wherein each matrix element is allocated to a different combination of transmitter ( 2 ) and receiver ( 3 ).
10. The apparatus according to claim 8 , characterized in that a switching device ( 6 ) is provided through which the transmit signals, by means of switching between the transmitters ( 2 ), can be transmitted in a chronological sequence via the transmitters ( 2 ).
11. The apparatus according to claim 8 , characterized in that the transmitters ( 2 ) and the receivers ( 3 ) are arranged two-dimensional in a plane, or one-dimensional in a row next to each other.
12. The apparatus according to claim 8 or claim 9 , characterized in that the antenna group ( 1 ) comprises less than ten transmitters ( 2 ) and less than ten receivers ( 3 ).
13. The apparatus according to claim 8 , characterized in that the transmit and receive device ( 5 ) is formed such that it switches the receivers ( 3 ) for the reception of the receive signals for the transmit signal transmitted by a transmitter ( 2 ), each within a common time window at the same time to reception mode.