Large-scale channel calibration method based on beam forming

Abstract

The invention relates to a large-scale channel calibration method based on beam forming, which is realized based on a monitoring T / R module, a transmitting antenna, a receiving antenna, a normal component, a beam forming module and a channel calibration module, and is characterized in that the monitoring T / R module generates a reference channel signal and sends the reference channel signal to the transmitting antenna and the channel calibration module; the transmitting antenna transmits a reference channel signal from the airspace through electromagnetic waves; the receiving antenna receives electromagnetic wave signals and converts the electromagnetic wave signals into electric signals; the normal component completes amplification, frequency mixing, sampling and filtering processing of the electric signal to form channel calibration data; the beam forming module receives all channel calibration data, completes beam forming processing and forms a beam; and the channel calibration module receives the reference channel signal and the beam data to complete channel calibration processing. According to the invention, through introduction of beam forming, calibration data of multiple channels are synthesized and processed into data of a single beam at the same time, so that the data volume is greatly reduced, and the subsequent test processing time of a test computer is saved.

Description

Technical Field

[0001] The present invention relates to the field of radar signal processing, and in particular to a large-scale channel calibration method based on beamforming. Background Art

[0002] The phased array radar antenna is composed of multiple antenna units, and each antenna unit can be arranged in different forms such as lines, planes, spheres, cylinders, and conformal surfaces according to the system design. By controlling the phase of the transmitted signal of each antenna unit, the energy is transmitted in the specified direction. Similarly, by controlling the phase of the received signal of each antenna unit, the energy reflected back from the specified direction can be received. In other words, the signal of each antenna unit is phase compensated, and finally the coherent processing of the signal of each antenna unit is realized. Therefore, the quality of each antenna unit will eventually affect the quality of the transmit lobe and the receive lobe.

[0003] In the actual system, each unit corresponds to a channel. Due to the inherent amplitude and phase differences of analog devices such as amplifiers, filters, and mixers in the components, the signal amplitude and phase consistency errors of each channel are inevitable. In order to ensure the coherent processing of the signals of each channel, each channel needs to be calibrated before work so that the amplitude and phase of the signals of each channel are as consistent as possible.

[0004] In large phased array radar antennas, there are many channels, up to tens of thousands or even hundreds of thousands. The resulting long channel calibration processing time and large data volume bring challenges to the channel calibration work. Therefore, a method that can meet the large-scale channel calibration needs of large phased array antennas is needed. Summary of the invention

[0005] In order to solve the problem that there are many large-scale array channels and a large amount of channel calibration data, resulting in slow data processing and low efficiency of the test computer, the present invention provides a large-scale channel calibration method based on beamforming.

[0006] The specific contents of the present invention are as follows: a large-scale channel calibration method based on beamforming, which is implemented based on a monitoring T / R module, a transmitting antenna, a receiving antenna, a normal component, a beam synthesis module and a channel calibration module, wherein the monitoring T / R module generates a reference channel signal and sends the reference channel signal to the transmitting antenna and the channel calibration module; the transmitting antenna transmits the reference channel signal generated by the monitoring T / R module from the airspace through electromagnetic waves; the receiving antenna receives the electromagnetic wave signal emitted by the transmitting antenna and converts it into an electrical signal; the normal component completes amplification, mixing, sampling and filtering of the electrical signal sent by the receiving antenna to form channel calibration data; the beam synthesis module receives the channel calibration data sent by all normal components, completes beam synthesis processing and forms a beam; the channel calibration module receives the reference channel signal sent by the monitoring T / R module and the beam data sent by the beam synthesis module to complete the channel calibration processing.

[0007] Furthermore, the beamforming module performs a beamforming process including: in a two-dimensional phased array, taking the array element (array surface unit) at the origin as a reference, defining its phase shift as zero, φ represents the azimuth angle of the receiving beam, θ represents the elevation angle of the receiving beam, and calculating the spatial phase difference between adjacent array surface units. The phase difference in the vertical direction is , The phase difference in the horizontal direction is , Let A mn is the amplitude weighting coefficient of the array element (m,n), then the expression of the array pattern function is , Where λ is the wavelength, d1 represents the unit spacing in the horizontal direction, d2 represents the unit spacing in the vertical direction, M and N are integers, exp[] represents a complex operation, exp(-j*θ)=cos(-θ)+j*sinθ, and Bmn represents the value to be compensated for the array element.

[0008] Furthermore, the channel calibration module adopts a channel calibration method of conjugate multiplication of the reference channel and the channel data to be calibrated, including: Let the channel to be calibrated be X A (K), the reference channel is X C (K), then the required calibration coefficient W is calculated as: , Where k is a positive integer, multiply the calculated W by the corresponding X A (K) channel to complete the channel calibration.

[0009] Further, according to the system timing and control information, the scanning frame is moved, and the transmitting antenna is moved and aligned to ch1 in the receiving antenna. The monitoring T / R module generates a reference channel signal and sends it to the transmitting antenna and the channel calibration module. The transmitting antenna receives the reference channel signal, converts it into an electromagnetic wave and transmits it. The receiving antenna receives the electromagnetic wave signal, converts it into an electrical signal, and sends it to the normal component. In the normal component, the mixing, sampling, and filtering of the electrical signal are completed to form channel calibration data. The channel calibration data is then sent to the beam synthesis module, and the beam synthesis processing is completed in the beam synthesis module to form beam data. The beam data is sent to the channel calibration module. In the channel calibration module, channel calibration processing is performed on the reference channel signal sent by the monitoring T / R module and the beam data sent by the beam synthesis module; then the transmitting antenna is moved and aligned to ch2, ch3 to chN in the receiving antenna in turn to complete the channel calibration processing of all channels of the entire array.

[0010] The present invention introduces beamforming to synthesize the calibration data of multiple channels into the data of a single beam, which greatly reduces the amount of data and saves the test processing time of subsequent test computers. In addition, the method is a completely closed-loop architecture and can realize continuous automatic batch calibration processing of array channels. The entire test process automatically tests, automatically records data, and automatically analyzes data without manual intervention, thereby improving the test efficiency of phased array antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The specific implementation of the present invention will be further explained below in conjunction with the accompanying drawings.

[0012] Figure 1 Schematic diagram of the large-scale channel calibration method of the present invention. DETAILED DESCRIPTION

[0013] Combination Figure 1 The large-scale channel calibration method based on beamforming of the present invention is implemented based on the following structure: Monitoring T / R module 1, used to generate reference channel signal, and send the reference channel signal to transmitting antenna 2 and channel calibration module 6; Transmitting antenna 2, used to transmit the reference channel signal generated by the monitoring T / R module 1 from the airspace through electromagnetic waves; The receiving antenna 3 receives the electromagnetic wave signal emitted by the transmitting antenna 2 and converts it into an electrical signal; Normal component 4, which refers to a normal T / R component, completes amplification, mixing, sampling, filtering and other processing of the electrical signal sent by the receiving antenna 3 to form channel calibration data; The beamforming module 5 receives the channel calibration data sent by all normal components 4, completes the beamforming process, forms a beam, realizes simultaneous multi-channel input and single beam output, and effectively reduces the amount of data.

[0014] The beamforming process is as follows: In a two-dimensional phased array, the array element at the origin is used as the reference, and its phase shift is defined as zero. φ represents the azimuth angle of the received beam, and θ represents the elevation angle of the received beam. Calculate the spatial phase difference between adjacent array elements: The phase difference in the vertical direction is , The phase difference in the horizontal direction is , Let A mn is the amplitude weighting coefficient of the array element (m,n), then the expression of the array pattern function is , Where λ is the wavelength, d1 represents the unit spacing in the horizontal direction, d2 represents the unit spacing in the vertical direction, M and N are integers, exp[] represents a complex operation, exp(-j*θ)=cos(-θ)+j*sinθ, and Bmn represents the value to be compensated for the array element.

[0015] Channel calibration 6 receives the reference channel signal sent by the monitoring T / R1 and the beam data sent by the beam synthesis module 5, completes the channel calibration process, and archives the reference channel signal, beam data and channel calibration results for subsequent use.

[0016] A channel calibration method is used that conjugates and multiplies the reference channel data with the channel data to be calibrated.

[0017] The specific algorithm is: Let the channel to be calibrated be X A (K), the reference channel is X C (K), then the calibration factor required for calculation is:

[0018] Multiply the calculated W by the corresponding X A (K) channel to complete the channel calibration.

[0019] The specific method of the present invention is as follows: According to the system timing and control, the scanning frame is moved, and the transmitting antenna 2 is moved and aligned to the ch1 of the receiving antenna 3. The monitoring T / R module 1 generates a reference channel signal and sends it to the transmitting antenna 2 and the channel calibration module 6. The transmitting antenna 2 receives the reference channel signal and converts it into an electromagnetic wave to be transmitted. The receiving antenna 3 receives the electromagnetic wave signal and converts it into an electrical signal and sends it to the normal component 4. In the normal component, the electrical signal is mixed, sampled, filtered, and other processes are completed to form channel calibration data. Then the channel calibration data is sent to the beam synthesis module 5. The beam synthesis process is completed in the beam synthesis module 5 to form beam data. The beam data is sent to the channel calibration module 6. In the channel calibration module 6, the reference channel signal sent by the monitoring T / R module 1 and the beam data sent by the beam synthesis 5 are channel-calibrated. At this point, the channel calibration process of one ch1 is completed. Then the transmitting antenna 2 is moved and aligned to the ch2, ch3 to chN of the receiving antenna 3 in turn to complete the channel calibration process of all channels of the entire array.

[0020] The following is an example of the present invention: In this example, there are 1000 receiving channels in total, and each channel is calibrated one by one. The dwell time and scanning frame movement time of each channel are about 10s in total. Each channel tests 100 frequency points, and the test frame period is 50ms.

[0021] According to the system timing and control, the scanning frame is moved, and the transmitting antenna is moved and aligned to the ch1 in the receiving antenna. The monitoring T / R module 1 generates a reference channel signal of frequency point 1, which is sent to the transmitting antenna 2 and the channel calibration module 6. The transmitting antenna 2 receives the reference channel signal, converts it into an electromagnetic wave and transmits it. The receiving antenna 3 receives the electromagnetic wave signal, converts it into an electrical signal, and sends it to the normal component 4. In the normal component, the electrical signal is amplified, mixed, sampled, filtered, and other processes are completed to form channel calibration data. The channel calibration data is then sent to the beam synthesis module 5, and the beam synthesis process is completed in the beam synthesis module 5 to form beam data. The beam data is sent to the channel calibration module 6. In the channel calibration module 6, the reference channel signal sent by the monitoring T / R module 1 and the beam data sent by the beam synthesis module 5 are channel-calibrated. At this point, the channel calibration process of frequency point 1 of ch1 is completed, and the reference channel signal, beam data, and channel calibration results are archived for subsequent use. In the above processing, if the beamforming process is not introduced, the channel calibration module 6 directly processes the channel calibration data. Due to the large amount of data, real-time processing of the data cannot be completed within the 50ms test frame period. After the beamforming process is introduced, the amount of beam data is reduced to 1 / 1000 of the original channel data, and the channel calibration module 6 can realize real-time processing of this data within the 50ms test frame period.

[0022] Without moving the scanning frame, follow the above method to complete the channel calibration test of frequency point 2 to frequency point 100 of ch1 in sequence. It takes a total of 5 seconds to test the 100 frequency points of ch1, and 5 seconds is reserved for the movement of the scanning frame, that is, it is estimated that a single channel will take 10 seconds.

[0023] The scanning frame is moved to align the transmitting antenna 2 to ch2, ch3 to chN of the receiving antenna 3 in turn, completing the channel calibration process of all frequency points of all channels of the entire array. The entire test takes a total of 10,000 seconds.

[0024] The method of the present invention has a completely closed-loop processing architecture. For the calibration processing of a single channel, the signal transmission, reception, beamforming processing and channel calibration processing are all performed according to system timing and control, and the whole process is automatically processed without human intervention. After the test of a single channel is completed, the test work of the next channel is automatically started according to the system timing and control, and the whole process is automatically processed without human intervention. And due to the introduction of beamforming processing, the calibration data of multiple channels is converted into single beam data, which greatly reduces the amount of data for channel calibration, thereby effectively improving the efficiency of the test work.

[0025] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A large-scale channel calibration method based on beamforming, characterized in that: It is implemented based on a monitoring T / R module, a transmitting antenna, a receiving antenna, normal components, a beamforming module and a channel calibration module, wherein the monitoring T / R module generates a reference channel signal and sends the reference channel signal to the transmitting antenna and the channel calibration module; the transmitting antenna transmits the reference channel signal generated by the monitoring T / R module from the airspace through electromagnetic waves; the receiving antenna receives the electromagnetic wave signal emitted by the transmitting antenna and converts it into an electrical signal; the normal components complete amplification, mixing, sampling and filtering of the electrical signal sent by the receiving antenna to form channel calibration data; the beamforming module receives the channel calibration data sent by all normal components, completes the beamforming processing and forms a beam; the channel calibration module receives the reference channel signal sent by the monitoring T / R module and the beam data sent by the beamforming module to complete the channel calibration processing.

2. The large-scale channel calibration method based on beamforming according to claim 1, characterized in that: The beam synthesis module performs the beam synthesis process including: in a two-dimensional phased array, taking the array element at the origin as the reference, defining its phase shift as zero, φ represents the azimuth angle of the received beam, θ represents the elevation angle of the received beam, and calculating the spatial phase difference between adjacent array elements. The phase difference in the vertical direction is ， The phase difference in the horizontal direction is ， Let A mn is the amplitude weighting coefficient of the array element (m,n), then the expression of the array pattern function is ， Where λ is the wavelength, d1 represents the unit spacing in the horizontal direction, d2 represents the unit spacing in the vertical direction, M and N are integers, exp[] represents a complex operation, exp(-j*θ)=cos(-θ)+j*sinθ, and Bmn represents the value that needs to be compensated for the array unit.

3. The large-scale channel calibration method based on beamforming according to claim 1, characterized in that: The channel calibration module adopts a channel calibration method that conjugates and multiplies the reference channel data with the channel data to be calibrated, including: Let the channel to be calibrated be X A (K), the reference channel is X C (K), then the required calibration coefficient W is calculated as: ， Where k is a positive integer, multiply the calculated W by the corresponding X A (K) channel to complete the channel calibration.

4. The large-scale channel calibration method based on beamforming according to claim 3, characterized in that: According to the system timing and control information, the scanning frame is moved, and the transmitting antenna is moved and aligned to ch1 in the receiving antenna. The monitoring T / R module generates a reference channel signal and sends it to the transmitting antenna and the channel calibration module. The transmitting antenna receives the reference channel signal, converts it into an electromagnetic wave and transmits it. The receiving antenna receives the electromagnetic wave signal, converts it into an electrical signal, and sends it to the normal component. In the normal component, the mixing, sampling, and filtering of the electrical signal are completed to form channel calibration data. The channel calibration data is then sent to the beam synthesis module, and the beam synthesis processing is completed in the beam synthesis module to form beam data. The beam data is sent to the channel calibration module. In the channel calibration module, channel calibration processing is performed on the reference channel signal sent by the monitoring T / R module and the beam data sent by the beam synthesis module; then the transmitting antenna is moved and aligned to ch2, ch3 to chN in the receiving antenna in turn to complete the channel calibration processing of all channels of the entire array.

Images