CN109596900B - Method and system for testing electrical axis deviation of multi-frequency antenna - Google Patents

Abstract

The invention provides a method and system for testing the electrical axis deviation of a multi-frequency antenna. The method includes: erecting a multi-frequency beacon source on the ground to ensure that there is no obstruction between the multi-frequency beacon source and the multi-frequency antenna; driving the multi-frequency antenna to align Multi-frequency beacon source; turn on the multi-frequency beacon source, wait for the multi-frequency antenna to enter the low-frequency automatic tracking state, continuously pull the multi-frequency antenna in the azimuth direction to obtain the azimuth error voltage sensitivity; restore the multi-frequency antenna to the initial position of the azimuth , continuously deflect the multi-frequency antenna in the pitch direction to obtain the pitch error voltage sensitivity, restore the multi-frequency antenna to the initial position, and wait for the multi-frequency antenna to enter the high-frequency automatic tracking state to obtain the average value of the azimuth tracking error voltage and the average value of the pitch tracking error voltage. value; after conversion and calibration, the angle deviation of the tracking zero point between the two frequency bands is obtained, which is the electric axis deviation of the multi-frequency antenna. The method is fast, reliable, and has strong operability, and has a positive effect on the multi-frequency antenna electrical axis deviation test in the field of ground receiving system testing.

Description

Method and system for testing electrical axis deviation of multi-frequency antenna

technical field

The invention relates to a method and a system for testing electric axis deviation of a multi-frequency antenna, belonging to the field of measurement and calibration of remote sensing satellite receiving systems.

Background technique

With the increasing demand for remote sensing applications, the ground data receiving systems of remote sensing satellite ground stations are required to have higher frequency data receiving capabilities. The frequency resources used in the remote sensing field began to rise to the Ka band. New multi-frequency antennas including Ka-band emerge as the times require, and gradually become a new development trend. The antenna system is one of the most important components of the ground data receiving system, and its performance is directly related to the data receiving performance of the entire ground data receiving system.

Multi-frequency shared feed (the antenna consists of a reflective surface and a feed, the feed is located at the focal point of the reflective surface, and the radio frequency signals gathered to the focal point are collected and transmitted to the channel equipment.) Generally, it is in the form of a multi-horn structure. Due to installation, debugging, etc. Uncontrollable factors may lead to inconsistent electrical axis beams (ie, electrical axis deviation) in different frequency bands of the feed when multiple frequency bands work at the same time. The Ka-band has higher frequencies, narrower beams, and higher accuracy requirements. Lower frequency bands such as S or X-band are often used to guide the Ka-band to capture and track satellite signals. The antenna electrical axis is the axis on which the peak of the antenna beam is located. For an antenna whose pattern is rotationally symmetric, the electrical axis is the ideal rotational symmetry axis. When the consistency of the antenna electric axis is poor, the tracking and guidance failure will occur, which will lead to the failure of acquisition and tracking, and then affect the final data reception. Therefore, the electrical axis deviation of the multi-frequency antenna including the Ka-band directly affects the acquisition and tracking performance of the Ka-band satellite. For multi-frequency antennas, the electrical axis deviation between different frequency bands is a test content that cannot be ignored, and needs to be tested during system testing. After the multi-frequency antenna electrical axis deviation is obtained after testing, the angle deviation can be used as the systematic error of the entire data receiving system to compensate and correct, so as to ensure that the lower frequency bands such as S or X can successfully guide the Ka frequency band to achieve capture and tracking. However, at present, there is no relevant measurement method for the test of the electrical axis deviation of the multi-frequency antenna including the Ka-band. Therefore, how to calibrate and measure the antenna electrical axis deviation between different frequency bands has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention proposes a method for testing the electrical axis deviation of a multi-frequency antenna, comprising the following steps:

a. Set up a multi-frequency beacon source;

b. Drive the multi-frequency antenna to align the multi-frequency beacon source;

c. Turn on the multi-frequency beacon source. The multi-frequency beacon source simultaneously transmits a low-frequency beacon signal and a high-frequency beacon signal. When the multi-frequency antenna enters the low-frequency automatic tracking state, the multi-frequency antenna is in the azimuth direction of the multi-frequency antenna. Continuously deflecting the preset deflection angle θ n times to obtain n groups of first azimuth tracking error voltages A _i , and obtaining the azimuth error voltage sensitivity K _A from the first azimuth tracking error voltages A _i , the formula is:

d. Restore the multi-frequency antenna to the initial position of the azimuth, and continuously deflect the multi-frequency antenna n times in the elevation direction to the preset deflection angle θ to obtain n groups of first pitch tracking error voltages E _i , which are determined by the A pitch tracking error voltage E _i is used to obtain the pitch error voltage sensitivity K _E , the formula:

e. Restore the multi-frequency antenna to the initial position, wait for the multi-frequency antenna to enter the high-frequency automatic tracking state, obtain the second azimuth tracking error voltage A _j and the second pitch tracking error voltage E _j corresponding to the middle and low frequency bands in steps c and d, and Obtain the average value of the azimuth tracking error voltage ε _A and the average value of the pitch tracking error voltage ε _E , where,

f. Calculate the electrical axis deviation σ between the low frequency band and the high frequency band, wherein the electrical axis deviation between the low frequency band and the high frequency band

Preferably, the way to confirm the alignment of the multi-frequency antenna with the multi-frequency beacon source is to drive the multi-frequency antenna to search for the highest signal power point of the multi-frequency beacon source.

Preferably, the range of the preset deflection angle θ is 0.06°˜0.2°.

Preferably, the method for generating the tracking error voltage is as follows: a low-frequency beacon signal and a high-frequency beacon signal transmitted by the multi-frequency beacon source are received by a multi-frequency antenna, and the antenna and the difference channel are separated to generate a low-frequency signal. A sum signal, a low-frequency difference signal, a high-frequency sum signal, and a high-frequency difference signal, and the low-frequency sum signal, a low-frequency difference signal, a high-frequency sum signal, and a high-frequency difference signal are respectively down-converted It is converted into an intermediate frequency signal and transmitted to the tracking receiver, and the tracking receiver demodulates the received signal to generate a tracking error voltage.

Preferably, the tracking error voltage is also fed back to the servo control system for controlling the multi-frequency antenna to direct the multi-frequency antenna to track the beacon signal.

Preferably, the high frequency band includes the Ka band.

Preferably, the multi-frequency beacon source is an S/Ka multi-frequency beacon source, and the multi-frequency antenna adopts an S/X/Ka tri-frequency antenna.

The present invention also provides a multi-frequency antenna electrical axis deviation test system, comprising a multi-frequency beacon source, a multi-frequency antenna, a tracking channel device, a tracking receiver and a test computer, wherein the multi-frequency beacon source is used for simultaneous A channel of low-band beacon signal and a channel of high-band beacon signal are transmitted; the multi-frequency antenna is used to receive the channel of low-band beacon signal and a channel of high-band beacon signal, and is separated by the antenna of the multi-band antenna and the difference channel and generate a low frequency sum signal, a low frequency difference signal, a high frequency sum signal, and a high frequency difference signal; the tracking channel device is used to combine the low frequency sum signal, a low frequency difference signal, a high frequency sum signal, One high frequency difference signal is converted into an intermediate frequency signal and transmitted to the tracking receiver; the tracking receiver is used to receive the intermediate frequency signal, and demodulate the received intermediate frequency signal to generate a tracking error voltage and transmit it to the test computer for recording; test A computer is used to record the tracking error voltage.

Preferably, a servo control system is also provided, and the servo control system is used to receive the tracking error voltage fed back by the tracking receiver and instruct the multi-frequency antenna to track the beacon signal.

Preferably, the tracking channel device comprises a downconverter.

【Beneficial effects】

Compared with the prior art, the present invention has the beneficial effects that the present invention proposes a method and system for testing the electrical axis deviation of a multi-frequency antenna based on the actual engineering needs in the field of remote sensing reception, which has the characteristics of accuracy and strong operability. The problem of electrical axis deviation that needs to be paid attention to when the antennas work in different frequency bands at the same time in the higher Ka-band is proposed, which provides a convenient test system and method for the Ka-band antenna test, and fills the Ka-band system. Test blank on axis deviation. As a kind of systematic error, the electric axis deviation obtained from the test can be corrected by corresponding compensation means, so that the low frequency band such as S or X can be used to guide the Ka frequency band to capture, track, and improve the success rate of remote sensing data reception in the Ka frequency band.

Description of drawings

The above-described features and technical advantages of the present invention will become more clearly and easily understood by describing its embodiments in conjunction with the following drawings.

1 is a schematic flowchart showing a method for testing the electrical axis deviation of a multi-frequency antenna according to an embodiment of the present invention;

Fig. 2 is the electric axis deviation test result of the S-band and Ka-band of the 12-meter aperture S/X/Ka antenna representing the embodiment of the present invention;

3 is a schematic structural diagram of a multi-frequency antenna electrical axis deviation testing system according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of the principle of a multi-frequency antenna electrical axis deviation testing system according to an embodiment of the present invention.

Detailed ways

Embodiments of the method and system for testing the electrical axis deviation of a multi-frequency antenna according to the present invention will be described below with reference to the accompanying drawings. As those of ordinary skill in the art would realize, the described embodiments may be modified in various different ways or combinations thereof, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and are not intended to limit the scope of protection of the claims. Furthermore, in this specification, the drawings are not drawn to scale, and the same reference numerals refer to the same parts.

The electrical axis deviation is to test the deviation of the low-frequency beam and the high-frequency beam of the electrical axis beam, that is, to test the deviation of the low-frequency beam tracking zero point and the high-frequency beam tracking zero point, which can also be called tracking zero point deviation.

FIG. 1 is a schematic flowchart showing a method for testing the electrical axis deviation of a multi-frequency antenna according to an embodiment of the present invention. As shown in Figure 1, the test method for the electrical axis deviation of the multi-frequency antenna includes the following steps:

a. Set up a multi-frequency beacon source, and there is no obstruction between the multi-frequency beacon source and the multi-frequency antenna. In this embodiment, the S/Ka multi-frequency beacon source is selected, and the multi-frequency antenna adopts the S/X/Ka tri-band antenna. It can be to choose a suitable place to set up the multi-frequency beacon source in the open space to ensure that there is no obstruction between the S/Ka beacon source module and the multi-frequency antenna. Among them, the beacon source is used to transmit a single carrier or modulated signal of a certain frequency, which is used for receiving during multi-frequency antenna testing.

b. Drive the multi-frequency antenna to align the multi-frequency beacon source.

c. Turn on the multi-frequency beacon source. The multi-frequency beacon source simultaneously transmits one low-frequency beacon signal and one high-frequency beacon signal. In this implementation, the multi-frequency beacon source simultaneously transmits S-band and Ka-band beacons Signal. The S/X/Ka tri-frequency antenna is controlled to be aligned with the beacon signal by the servo control system, and the position of the multi-frequency antenna at this time is marked as the initial position. When the multi-frequency antenna enters the low-band automatic tracking state, that is, when the S/X/Ka tri-band antenna is in the "S-band automatic tracking" mode, the multi-frequency antenna is continuously deflected n times by the preset deflection angle θ in the azimuth direction. In this embodiment, the single pull is 0.06°, which is converted into a distance of 1 mil. Read the data displayed by the servo control system in the test computer to obtain n groups of first azimuth tracking error voltages A _i , obtain the azimuth error voltage sensitivity K _A from the first azimuth tracking error voltage A _i , and the azimuth error voltage sensitivity K _A The unit is mv/mil, where

d. Restore the multi-frequency antenna to the initial position of the azimuth, and continuously pull the multi-frequency antenna to the preset deflection angle θ n times in the elevation direction. In this embodiment, the single deflection is 0.06°, which is converted into a distance of 1 mil. That is, the deflection angle in the pitch direction is the same as the deflection angle in the azimuth direction. The data displayed by the servo control system is read in the test computer to obtain n groups of first pitch tracking error voltages E _i , and the pitch error voltage sensitivity KE is obtained from the first pitch tracking error voltage _{E i} , wherein

e. Restore the multi-frequency antenna to its initial position, and wait until the multi-frequency antenna enters the high-frequency automatic tracking state, that is, until it enters the "Ka-frequency automatic tracking" mode, and obtain the second azimuth tracking error voltage A corresponding to the middle and low frequency bands in steps c and d. _j and the second pitch tracking error voltage E _j , and obtain the average value of the azimuth tracking error voltage ε _A and the average value of the pitch tracking error voltage ε _E , where,

f. Calculate the electrical axis deviation between the low frequency band and the high frequency band, where the electrical axis deviation between the low frequency band and the high frequency band

Further, in order to improve the test accuracy, steps c to f are repeated several times, and the average value of the coaxiality deviation is obtained. Preferably, steps c to f are repeated no less than 5 times.

As an embodiment of the present invention, the actual measurement result of the deviation between the Ka-band beam and the electric axis beam of the S-band beam is obtained after actual construction and testing, as shown in FIG. 2 . The coaxiality deviation of S/Ka of the system is 0.021°, which satisfies the proposed S/Ka coaxiality deviation of ≤0.025°.

In an optional embodiment, the way to confirm the alignment of the multi-frequency antenna with the multi-frequency beacon source is to drive the multi-frequency antenna to find the highest signal power point of the multi-frequency beacon source.

In an optional embodiment, the preset deflection angle ranges from 0.06° to 0.2°.

The above-mentioned azimuth tracking error voltage and pitch tracking error voltage are both tracking error voltages. In an optional embodiment, the method for generating the tracking error voltage is as follows: a low-frequency beacon signal transmitted by the multi-frequency beacon source and a The high-frequency beacon signal is received by the multi-frequency antenna, separated by the antenna and the difference channel, and generates a low-frequency sum signal, a low-frequency difference signal, a high-frequency sum signal, and a high-frequency difference signal, and the low-frequency sum signal is generated. , a low frequency difference signal, a high frequency sum signal, and a high frequency difference signal are respectively converted into intermediate frequency signals by downconverters and transmitted to the tracking receiver, and the tracking receiver demodulates the received signal to generate a tracking error voltage.

In an alternative embodiment, the tracking error voltage is also fed back to a servo control system for controlling the multi-frequency antenna to direct the multi-frequency antenna to track the beacon signal.

The present invention also provides a multi-frequency antenna electrical axis deviation test system, as shown in FIG. 3 , including a multi-frequency beacon source, a multi-frequency antenna, a tracking channel device, a tracking receiver and a test computer, wherein the multi-frequency The beacon source simultaneously transmits a low-frequency beacon signal and a high-frequency beacon signal and is received by a multi-frequency antenna. The antenna and the difference channel are separated to generate a low-frequency sum signal, a low-frequency difference signal, a high-frequency sum signal, and a The high frequency difference signal, and the one low frequency sum signal, one low frequency difference signal, one high frequency sum signal, and one high frequency difference signal are respectively converted into intermediate frequency signals by the tracking channel equipment and transmitted to the tracking receiver, and the tracking receiver converts all the signals. The received signal is demodulated to generate a tracking error voltage which is transmitted to the test computer for recording. As shown in Figure 4, the S/Ka multi-frequency beacon source transmits one S-band beacon signal and one Ka-band beacon signal, and the sum and difference channels of the S/X/Ka tri-band antenna are separated to generate the S-band sum signal, S-band difference signal, Ka-band sum signal, Ka-band difference signal. The S-band sum signal and the S-band difference signal are converted into the S-band sum IF signal and the S-band difference IF signal through the S downconverter. The Ka-band sum signal and the Ka-band difference signal are converted into the Ka-band sum-channel IF signal and the Ka-band difference channel IF signal through the Ka downconverter.

In an optional embodiment, a servo control system is further provided, and the tracking receiver feeds back the tracking error voltage to the servo control system of the multi-frequency antenna, so as to instruct the multi-frequency antenna to track the beacon signal.

The test error term introduced by the test system in this embodiment is described below:

1) Deviation of the S/Ka calibration source: In this embodiment, the S and Ka-band beacon antennas in the system have a position deviation of 5cm from the preset installation position during installation, and at a straight-line distance of 6.6km (multi-frequency beacon source and The coaxiality deviation introduced on the distance of the multi-frequency feed is 0.0004°.

2) Test error introduced by tracking accuracy: in this embodiment, the tracking accuracy of the Ka-band of the system is about 0.0007°.

3) The deviation of the error sensitivity, that is, the conversion error from the error voltage to the deflection angle: in this embodiment, the minimum reading scale of the error voltage of the system is 1mv, and considering that its accuracy will deteriorate by an order of magnitude on this basis, it is 10mv, Then the introduced deflection angle deviation is about 0.0012° in the S-band. To sum up, the total test error of the system in this embodiment is 0.0023°. That is, the test accuracy of this method is 0.002°, which is about 1/10 of the measured value, which meets the test requirements.

Table 1 is a statistical table of coaxiality deviation results in the S and Ka frequency bands of the embodiment, which is briefly described below with reference to Table 1. Among them, the azimuth value of Ka default zero point is 136.576°, and the pitch value is 1.471°. The azimuth error voltage sensitivity K _A , the pitch error voltage sensitivity KE , the azimuth tracking error voltage average ε _A , the pitch tracking error voltage average ε _E are obtained by measurement, and the difference between the low frequency band and the high frequency band can be calculated by the formula of step f _. The electric axis deviation between σ. Repeat the measurement and calculation to obtain σ 5 times, and finally calculate the average value to obtain the average value of coaxial deviation σ of 0.021°.

Table I

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A method for testing deviation of an electric axis of a multi-frequency antenna is characterized by comprising the following steps:

a. erecting a multi-frequency beacon source;

b. driving a multi-frequency antenna to align with a multi-frequency beacon source;

c. starting a multi-frequency beacon source, wherein the multi-frequency beacon source simultaneously transmits a low-frequency-band beacon signal and a high-frequency-band beacon signal, and when the multi-frequency antenna enters a low-frequency-band automatic tracking state, continuously biases the multi-frequency antenna in the azimuth direction for n times by a preset bias angle theta to obtain n groups of first partiesBit tracking error voltage A_iTracking the error voltage A from the first orientation_iObtaining the voltage sensitivity K of the azimuth error_AThe formula is as follows:

d. restoring the multi-frequency antenna to the azimuth initial position, continuously deflecting the multi-frequency antenna for n times in the pitching direction by the preset deflection angle theta to obtain n groups of first pitching tracking error voltages E_iFrom said first pitch tracking error voltage E_iObtaining a pitch error voltage sensitivity K_EThe formula is as follows:

e. c, restoring the multi-frequency antenna to the initial position, and obtaining a second azimuth tracking error voltage A corresponding to the low-frequency band in the steps c and d when the multi-frequency antenna enters a high-frequency band automatic tracking state_jAnd a second pitch tracking error voltage E_jAnd obtaining the mean value epsilon of azimuth tracking error voltage_APitch tracking error voltage mean epsilon_EWherein, in the step (A),

f. calculating the electric axis deviation sigma between the low frequency band and the high frequency band, wherein the electric axis deviation sigma between the low frequency band and the high frequency band

2. The test method according to claim 1,

the method for confirming the alignment of the multi-frequency antenna and the multi-frequency beacon source is to drive the multi-frequency antenna to search the highest signal power point of the multi-frequency beacon source.

3. The test method according to claim 1, wherein the preset pull-off angle θ is in a range of 0.06 ° to 0.2 °.

4. The test method according to claim 1,

the method of generating the tracking error voltage is as follows:

the low-frequency band beacon signal of the same way of multifrequency beacon source transmission and high-frequency band beacon signal of the same way are received through the multifrequency antenna, are separated by antenna and poor passageway and generate low-frequency band and signal of the same way, low-frequency band difference signal of the same way, high-frequency band and signal of the same way, high-frequency band difference signal of the same way, just low-frequency band and signal of the same way, low-frequency band difference signal of the same way, high-frequency band and signal of the same way, high-frequency band difference signal of the same way turn into intermediate frequency signal transmission to tracking receiver through down converter respectively, and tracking receiver generates.

5. The test method according to claim 1,

the tracking error voltage is also fed back to a servo control system for controlling the multi-frequency antenna to guide the multi-frequency antenna to track the beacon signal.

6. The test method according to claim 1,

the high frequency band includes a Ka band.

7. The method of claim 6, wherein the multi-frequency beacon source is an S/Ka multi-frequency beacon source, and the multi-frequency antenna is an S/X/Ka tri-frequency antenna.

8. A test system for electric axis deviation of a multi-frequency antenna is characterized by comprising a multi-frequency beacon source, a multi-frequency antenna, a tracking channel device, a tracking receiver and a test computer, wherein the multi-frequency beacon source is used for simultaneously transmitting a low-frequency-band beacon signal and a high-frequency-band beacon signal;

the multi-frequency antenna is used for receiving the low-frequency-band beacon signal and the high-frequency-band beacon signal, and is separated by an antenna and a difference channel of the multi-frequency antenna to generate a low-frequency-band sum signal, a low-frequency-band difference signal, a high-frequency-band sum signal and a high-frequency-band difference signal;

the tracking channel equipment is used for respectively converting the low-frequency band sum signal, the low-frequency band difference signal, the high-frequency band sum signal and the high-frequency band difference signal into intermediate-frequency signals and transmitting the intermediate-frequency signals to the tracking receiver;

the tracking receiver is used for receiving the intermediate frequency signal, demodulating the received intermediate frequency signal to generate tracking error voltage and transmitting the tracking error voltage to a test computer for recording;

the test computer is used for recording the tracking error voltage.

9. The test system of claim 8, further comprising a servo control system, wherein the servo control system is configured to receive the tracking error voltage fed back by the tracking receiver and direct the multi-frequency antenna to track the beacon signal.

10. The test system of claim 8, wherein the tracking channel device comprises a down converter.

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