CN114374090A - Receiving channel phase calibration method of phased array antenna - Google Patents

Abstract

The invention discloses a phase calibration method of a receiving channel of a phased array antenna, which belongs to the technical field of communication and radar. Based on the phase calibration system, the phase calibration system includes N antennas (N is a natural number greater than or equal to 2), N receiving channels, an amplitude and phase controller, a signal amplitude detector and a computer. There is no need for vector measurement equipment such as vector network analyzers. The phase shifter, attenuator, receiver or amplitude detector of the phased array system itself can be used as signal amplitude detectors to realize multiple amplitude measurements. Efficient automated calibration.

Description

A method for calibrating the phase of the receiving channel of a phased array antenna

technical field

The present invention relates to the technical field of communication and radar, in particular to a method for calibrating the phase of a receiving channel of a phased array antenna.

Background technique

In the field of communication and radar, phased array antenna is a relatively advanced form of antenna, which can realize fast electronic beam tracking without the need of traditional mechanical tracking system, and has the advantages of fast tracking speed and so on. The phased array antenna has many antenna elements and its feeder, receiving channel and transmitting channel. In order to obtain the ideal synthesis effect, it is necessary to accurately know the phase calibration value of each channel from the antenna to the channel. Therefore, it is necessary to perform phase calibration. Calibration work. An efficient and convenient phase calibration system has become one of the important tasks in the development of phased array antennas.

In the conventional phased array antenna phase system, it is necessary to measure the phase characteristics of each channel, so it is necessary to use a vector network analyzer for vector measurement, which requires a high instrument.

The method based on multi-channel amplitude measurement is also often used in phased array calibration. Each phase shifter works in different phase-shifting states, and the result of the total field is measured by a fixed probe to solve the phase/amplitude characteristics of each channel. Array element method (measurement of two elements), rotating vector method (The rotating element electric fieldvector method) and its improvement methods, etc., but the workload is large and the efficiency is low.

SUMMARY OF THE INVENTION

The purpose of the present invention is to avoid the deficiencies in the above background technology and provide a high-efficiency phased array antenna receiving channel calibration method based on sum signal amplitude measurement, which does not require vector measurement equipment such as a vector network analyzer, and uses The phase shifter, attenuator, receiver or amplitude discriminator of the phased array system itself can be used as a signal amplitude detector to realize multiple amplitude measurements. Through computer control, high-efficiency automatic calibration can be realized.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A receiving channel phase calibration method of a phased array antenna is implemented based on a phase calibration system, wherein the phase calibration system includes N channels of receiving channels, an amplitude-phase controller, a signal amplitude detector and a computer, wherein the amplitude-phase controller includes a combining circuit N-channel phase shifter and N-channel attenuator, where N is a natural number greater than or equal to 2, corresponding to the number of receiving channels; the specific process includes the following:

(1) The computer sends out the initial state control command to make the amplitude and phase controller in the initial state, that is, the phase value of each phase shifter in the amplitude and phase controller is 0°, and the attenuation value of each attenuator is 0dB;

(2) Select one receiving channel as the reference channel, and select one channel from other channels except the reference channel as the current channel;

(3) Send out calibration control commands through the computer, and set the state of the current channel and reference channel medium amplitude and phase controllers respectively; after the setting is completed, the electromagnetic signals of the N channels of receiving channels are sent to the corresponding N channels of phase shifters and N channels of attenuators respectively. into the combiner for synthesis, and then detected by the signal amplitude detector, and the signal amplitude detection result is sent to the computer;

(4) Select another channel as the current channel from other channels except the reference channel, and return to step (3) until all channels are detected;

(5) The computer calculates the phase difference between each channel and the reference channel according to the signal amplitude detection result, and sets the N-channel phase shifters in the amplitude-phase controller according to the phase difference.

Wherein, in step (3), the state of the current channel and the reference channel medium amplitude and phase controller are respectively set, which specifically includes the following process:

Set the attenuation of the attenuators in the current channel and the reference channel to 0dB, the phaser of the phaser to 0°, and set the attenuation of the attenuators in other channels except the current channel and the reference channel to the maximum attenuation , read the measured value A ₁ of the signal amplitude detector at this time;

Change the phase shift amount of the phase shifter in the current channel to 180°, and read the measured value A ₂ of the signal amplitude detector at this time;

Change the phase shift amount of the phase shifter in the current channel to 90°, and read the measured value A ₃ of the signal amplitude detector at this time;

Change the phase shift amount of the phase shifter in the current channel to 270°, and read the measured value A ₄ of the signal amplitude detector at this time.

Wherein, in step (5), the phase difference Φ between each channel and the reference channel is calculated according to the signal amplitude detection result, and the specific calculation method is:

Φ=arctan((A ₄ -A ₃ )/(A ₁ -A ₂ )).

Compared with the background technology, the present invention has the following beneficial effects:

1. The present invention is equipped with an amplitude-phase controller and a signal amplitude detector, which can detect the amplitude value of the combined signal under different amplitude and phase states, and can obtain the phase calibration value of each receiving channel after calculation, without vector measurement. .

2. The present invention utilizes the phase shifter, attenuator and receiver or amplitude discriminator of the phased array system itself as a signal amplitude detector to realize amplitude measurement, and realizes high-efficiency automatic calibration through computer control.

Description of drawings

FIG. 1 is a block diagram of a system in an embodiment of the present invention.

FIG. 2 is a block diagram of the amplitude and phase controller in FIG. 1 according to an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

1 and 2, a phase calibration method for a receiving channel of a phased array antenna is implemented based on a phase calibration system, and the phase calibration system includes N antennas (N is a natural number above 2), N channels of reception channels, A phase controller, a signal amplitude detector and a computer are provided. The amplitude and phase controller includes a combiner, an N-way phase shifter and an N-way attenuator. Embodiment N is 4. The 4 antennas are distributed in an equidistant linear array, and receive a certain electromagnetic signal from space at the same time. The signal received by each antenna is then transmitted to its own connected receiving channel. Each receiving channel can be adjusted according to system requirements. It has processing functions such as amplification and frequency conversion, and the signal processed by the receiving channel is then transmitted to the corresponding input port of the amplitude-phase controller; the amplitude-phase controller includes 4 phase shifters, 4 attenuators and a combiner. The function of the phaser is to perform phase-shift processing on the input signal, using a 6-bit phaser with a minimum step of 5.6°, and the function of the attenuator is to attenuate the input signal, using a 5-bit attenuator with a minimum step of 1dB, The maximum attenuation is 31dB. The 4-channel signals entering the amplitude-phase controller are respectively processed by phase-shifting and attenuation, and then sent to the combiner to synthesize the 4-channel signals, and then output to the signal amplitude detector.

The computer sends out an initial state control command to make the amplitude-phase controller in the initial state, that is, the phase value of each phase shifter in the amplitude-phase controller is 0°, and the attenuation value of each attenuator is 0dB . Four antennas receive electromagnetic signals from far away at the same time, and send them to the amplitude and phase controller through four receiving channels. The computer sends out calibration control instructions, 4 phase shifters and 4 attenuators change states under the command control, the signal amplitude detector measures the signal amplitude after the 4 phase shifters and 4 attenuators and the combiner, And send the signal amplitude detection result to the computer. After many times of the above measurement process, the corresponding data of different states of the amplitude and phase controllers and the detection results of the signal amplitude are obtained, and the phase calibration value of each receiving channel can be obtained through computer data processing.

Embodiment For a phased array antenna calibration system with 4 antennas and receiving channels, the measurement process is divided into 3 steps. The first step is to calibrate the phase difference between the first channel and the second channel, which is divided into the following 4 amplitude measurements:

1) Set the attenuation of the third attenuator and the fourth attenuator to the maximum attenuation, the attenuation of the first attenuator and the second attenuator to 0dB, and the phase shifter of the first phase shifter. is 0°, the phase shift amount of the second phase shifter is 0°, and the measured value A1 of the signal amplitude detector is read at this time;

2) The other states remain unchanged, only the phase shift amount of the second phase shifter is changed to 180°, and the measured value A2 of the signal amplitude detector is read at this time;

3) The other states remain unchanged, only the phase shift amount of the second phase shifter is changed to 90°, and the measured value A3 of the signal amplitude detector is read at this time;

4) The other states remain unchanged, only the phase shift amount of the second phase shifter is changed to 270°, and the measured value A4 of the signal amplitude detector is read at this time.

At this time, taking the first channel as a reference, the phase difference Φ2 between the second channel and the first channel is calculated by the following formula:

Φ2=arctan((A4-A3)/(A1-A2))

The second step is to calibrate the phase difference between the first channel and the third channel, set the attenuation of the second channel attenuator and the fourth channel attenuator to the maximum attenuation, and change the phase shift amount of the third channel phase shifter. Also perform the above 4 amplitude measurements to obtain 4 measured values B1, B2, B3, B4 respectively. At this time, taking the first channel as a reference, the phase difference Φ3 between the third channel and the first channel uses the following formula calculate:

Φ3=arctan((B4-B3)/(B1-B2))

The third step is to calibrate the phase difference between the first channel and the fourth channel, set the attenuation of the second channel attenuator and the third channel attenuator to the maximum attenuation, and change the phase shift amount of the fourth channel phase shifter. Also perform the above 4 amplitude measurements, and obtain 4 measured values C1, C2, C3, C4 respectively. At this time, with the first channel as a reference, the phase difference Φ4 between the fourth channel and the first channel uses the following formula calculate:

Φ4=arctan((C4-C3)/(C1-C2))

Finally, the calibration results of the four antennas and receiving channels are (0, Φ2, Φ3, Φ4), where 0, Φ2, Φ3, and Φ4 are the calibration values of the first, second, third, and fourth channels, respectively. , and set the four phase shifters in the amplitude and phase controller to 0, Φ2, Φ3, and Φ4 respectively, then the phase calibration of the phased array antenna receiving channel is completed.

Claims (3)

1. A phase calibration method of a receiving channel of a phased array antenna is realized based on a phase calibration system, the phase calibration system comprises N paths of receiving channels, an amplitude phase controller, a signal amplitude detector and a computer, the amplitude phase controller comprises a combiner, N paths of phase shifters and N paths of attenuators, wherein N is a natural number more than or equal to 2; the method is characterized by comprising the following steps:

(1) the computer sends out an initial state control instruction to enable the amplitude controller to be in an initial state, namely the phase value of each phase shifter in the amplitude controller is 0 degrees, and the attenuation value of each attenuator is 0 dB;

(2) selecting a receiving channel as a reference channel, and selecting one channel from other channels except the reference channel as a current channel;

(3) sending a calibration control instruction through a computer, and respectively setting the states of the amplitude phase controllers in the current channel and the reference channel; after the setting is finished, the electromagnetic signals of the N receiving channels respectively and correspondingly pass through the N phase shifters and the N attenuators and then are sent to the combiner for synthesis, and then are detected by the signal amplitude detector, and the signal amplitude detection result is sent to the computer;

(4) selecting another channel from the other channels except the reference channel as the current channel, and returning to the step (3) until all the channels are detected;

(5) and the computer respectively calculates the phase difference between each channel and the reference channel according to the signal amplitude detection result, and respectively sets N phase shifters in the amplitude-phase controller according to the phase difference.

2. The method for calibrating the phase of the receiving channel of the phased array antenna according to claim 1, wherein the step (3) of setting the states of the amplitude controllers in the current channel and the reference channel respectively comprises the following steps:

setting the attenuation amounts of the attenuators in the current channel and the reference channel to be 0dB, setting the phase shift amount of the phase shifter to be 0 DEG, setting the attenuation amounts of the attenuators in the other channels except the current channel and the reference channel to be the maximum attenuation amount, and reading the measurement value A of the signal amplitude detector at the moment₁；

The phase shift amount of the phase shifter in the current channel is changed to 180 degrees, and the amplitude detector of the read signal at the momentMeasured value A of₂；

The phase shift amount of the phase shifter in the current channel is changed to 90 DEG, and the measured value A of the signal amplitude detector is read₃；

The phase shift amount of the phase shifter in the current channel is changed to 270 °, and the measurement value A of the signal amplitude detector is read₄。

3. The method for calibrating the phase of the receiving channel of the phased array antenna according to claim 2, wherein the phase difference Φ between each channel and the reference channel is calculated according to the signal amplitude detection result in the step (5) by:

Φ＝arctan((A₄-A₃)/(A₁-A₂))。

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