CN108088570B - A Radiometer Imaging Method Based on Phased Array Scanning System - Google Patents

Abstract

The invention discloses a radiometer imaging method based on a phased array scanning system, comprising: a control computer (1), a millimeter wave radiometer (2), a DC power supply II (3), a DC power supply III (4), a phase control array antenna (5), DC power supply I (6), millimeter wave noise head (7) and precision attenuator (8). Under the excitation of the +28V DC voltage of the DC power supply I, the millimeter-wave noise head generates an accurately calibrated noise temperature output in the required millimeter-wave band, and the precision attenuator outputs the required noise temperature through the millimeter-wave manual adjustment. The control computer (1) controls the beam switching of the phased array antenna, and performs two-dimensional image acquisition and storage. Compared with the traditional radiometer imaging method, the invention only needs one radiometer and does not need a servo mechanism, and has the advantages of simple equipment, simple operation, adjustable test equivalent noise temperature, and the like.

Description

A Radiometer Imaging Method Based on Phased Array Scanning System

technical field

The invention relates to a radiometer imaging method, in particular to a radiometer imaging method based on a phased array scanning system.

Background technique

A single radiometer can only feed back the temperature signal to the pointing point. To use a radiometer to image in a two-dimensional plane, it is mainly done by using a radiometer array composed of multiple radiometers and a motion servo mechanism. The number of radiometers determines one. The resolution of the dimension, the magnitude of the motion of the motion servo determines another dimension. This method requires more radiation and a dedicated motion mechanism, the cost is high, there is temperature drift between multiple radiometers, the calibration is complicated, and the imaging range and resolution are difficult to change. This test method has problems such as complex test equipment and test environment, high requirements for the temperature consistency of the radiation source, long test time, and low efficiency.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a radiometer imaging method based on a phased array scanning system, which solves the problems of high temperature consistency requirements, complex test procedures, long test time and low efficiency between radiometers using the traditional test method.

A radiometer imaging method based on a phased array scanning system, the specific steps are:

The first step is to build a radiometer imaging system based on a phased array scanning system

The radiometer imaging system based on phased array scanning system includes: control computer, millimeter wave radiometer, DC power supply II, DC power supply III, phased array antenna, DC power supply I, millimeter wave noise head and precision attenuator.

The 28V voltage output end of the DC power supply I is connected to the input end of the millimeter wave noise head; the noise temperature output end of the millimeter wave noise head is connected to the input end of the precision attenuator; the output end of the precision attenuator is connected to the input end of the millimeter wave radiometer The output end of the millimeter wave radiometer is connected with the phased array antenna; the output end of the DC power supply II is connected with the DC bias end of the millimeter wave radiometer. The output voltage adjustment range of DC power supply II is 0-25V, and the output voltage of DC power supply III is 56V.

The control computer includes an acquisition control module, and the functions of the acquisition control module are: controlling the beam switching of the phased array antenna, and performing two-dimensional image acquisition and storage.

The second step is to warm up and stabilize the working state

Perform power-on preheat stabilization operation, set the required voltage value, and connect to the corresponding bias port. After the millimeter-wave radiometer, the three DC power supplies and the phased array antenna are in stable working conditions, the test process can be carried out.

The third step determines the number of scanning points and coordinates

The azimuth and elevation coordinates of the scanned image of the millimeter-wave radiometer are determined according to the scanning interval angle. Suppose the scanning interval is θ, and the scanning angle ranges in azimuth and elevation directions are α and β, respectively. Then the scanning points m and n in the azimuth and elevation directions are respectively

Where [ ] means round down. The coordinates of each point are

The fourth step is to calibrate the millimeter wave radiometer and the phased array antenna by the acquisition control module

The acquisition control module calibrates the millimeter wave radiometer and the phased array antenna. Aim the phased array antenna at the 70°C high temperature constant temperature source, and collect the calibration data vecHot[mn] of the 70°C high temperature constant temperature source; then align the phased array antenna with the -10°C low temperature constant temperature source, and collect the -10°C low temperature constant temperature Source calibration data vecCold[mn]; get low temperature average:

AveCold: low temperature average;

vecCold[i]: the i-th low temperature value;

The average value of the difference between high temperature and low temperature:

DiffAve: the average value of the difference between high temperature and low temperature;

vecHot[i]: high temperature value of the i-th road;

The fifth step is to calibrate the target image

Collect the target image, obtain the image data OriginalData[mn], and finally perform calibration compensation on the target image, and perform separate compensation for each millimeter-wave radiometer point:

CompensateData[i]: The data after the i-th internal calibration compensation;

OriginalData[i]: The data before the i-th internal calibration compensation;

AveCold: low temperature average;

DiffAve: the average value of the difference between high temperature and low temperature;

Finally, the CompensateData[i] is synthesized to obtain the compensated data CompensateData[mn], and the internal calibration is completed.

This method proposes a radiometer imaging method based on a phased array scanning system, which meets the requirements of small volume, high measurement accuracy imaging and short test time. The DC power supply I supplies the 28V DC voltage required by the millimeter wave noise head. Under the excitation of the 28V DC voltage, the millimeter wave noise head produces an accurately calibrated noise temperature output in the required millimeter wave band. After the millimeter wave manually adjusts the output of the precision attenuator. desired noise temperature. The millimeter wave manual adjustment precision attenuator can complete the change of different attenuation under the control of the manual knob outside the chassis, so as to output different noise temperatures, which will be used as the benchmark for the temperature sensitivity measurement of the radiometer. The acquisition control module in the control computer controls the beam switching of the phased array antenna, and performs two-dimensional image acquisition and storage. The radiometer imaging method proposed by the invention can simplify the testing process, improve the testing efficiency and reduce the testing cost.

Description of drawings

Fig. 1 is a schematic diagram of the system composition of a radiometer imaging method based on a phased array scanning system;

1. Control computer 2. Millimeter wave radiometer 3. DC power supply II 4. DC power supply III 5. Phased array antenna 6. DC power supply I 7. Millimeter wave noise head 8. Precision attenuator

Detailed ways

A radiometer imaging method based on a phased array scanning system, the specific steps are:

The first step is to build a radiometer imaging system based on a phased array scanning system

Radiometer imaging system based on phased array scanning system, including: control computer 1, millimeter wave radiometer 2, DC power supply II3, DC power supply III4, phased array antenna 5, DC power supply I6, millimeter wave noise head 7 and precision attenuation device 8.

The 28V voltage output end of the DC power supply I6 is connected with the input end of the millimeter wave noise head 7; the noise temperature output end of the millimeter wave noise head 7 is connected with the input end of the precision attenuator 8; the output end of the precision attenuator 8 is connected with the millimeter wave radiation The input end of the meter 2 is connected; the output end of the millimeter wave radiometer 2 is connected with the phased array antenna 5 ; the output end of the DC power supply II3 is connected with the DC bias end of the millimeter wave radiometer 2 . The output voltage adjustment range of DC power supply II3 is 0-25V, and the output voltage of DC power supply III4 is 56V.

The control computer 1 includes an acquisition control module, and the functions of the acquisition control module are: controlling the beam switching of the phased array antenna 5, and performing two-dimensional image acquisition and storage.

The second step is to warm up and stabilize the working state

Perform power-on preheat stabilization operation, set the required voltage value, and connect to the corresponding bias port. After the millimeter wave radiometer 2 , the three DC power supplies and the phased array antenna 5 are in stable working states, the test process is performed.

The third step determines the number of scanning points and coordinates

The azimuth and elevation coordinates of the scanned image of the millimeter-wave radiometer 2 are determined according to the scanning interval angle. Suppose the scanning interval is θ, and the scanning angle ranges in azimuth and elevation directions are α and β, respectively. Then the scanning points m and n in the azimuth and elevation directions are respectively

Where [ ] means round down. The coordinates of each point are

Step 4: The acquisition control module calibrates the millimeter wave radiometer 2 and the phased array antenna 5

The acquisition control module calibrates the millimeter wave radiometer 2 and the phased array antenna 5 . Align the phased array antenna 5 with the 70°C high temperature constant temperature source, and collect the calibration data vecHot[mn] of the 70°C high temperature constant temperature source; then align the phased array antenna 5 with the -10°C low temperature constant temperature source, and collect -10°C Low temperature constant temperature source calibration data vecCold[mn]; get low temperature average value:

AveCold: low temperature average;

vecCold[i]: the i-th low temperature value;

The average value of the difference between high temperature and low temperature:

DiffAve: the average value of the difference between high temperature and low temperature;

vecHot[i]: high temperature value of the i-th road;

The fifth step is to calibrate the target image

Collect the target image, obtain the image data OriginalData[mn], and finally perform calibration compensation on the target image, and perform separate compensation for 2 points of each millimeter-wave radiometer:

CompensateData[i]: The data after the i-th internal calibration compensation;

OriginalData[i]: The data before the i-th internal calibration compensation;

AveCold: low temperature average;

DiffAve: the average value of the difference between high temperature and low temperature;

Finally, the CompensateData[i] is synthesized to obtain the compensated data CompensateData[mn], and the internal calibration is completed.

Claims (1)

1. a radiometer imaging method based on phased array scanning system, is characterized in that concrete steps are: The first step is to build a radiometer imaging system based on a phased array scanning system A radiometer imaging system based on a phased array scanning system, comprising: a control computer (1), a millimeter wave radiometer (2), a DC power supply II (3), a DC power supply III (4), a phased array antenna (5), DC power supply I (6), millimeter wave noise head (7) and precision attenuator (8); The 28V voltage output end of the DC power supply I (6) is connected with the input end of the millimeter wave noise head (7); the noise temperature output end of the millimeter wave noise head (7) is connected with the input end of the precision attenuator (8); the precision attenuation The output end of the device (8) is connected with the input end of the millimeter wave radiometer (2); the output end of the millimeter wave radiometer (2) is connected with the phased array antenna (5); the output end of the DC power supply II (3) is connected with the phased array antenna (5). The DC bias terminal of the millimeter wave radiometer (2) is connected, and the output terminal of the DC power supply III (4) is connected to the phased array antenna (5). The output voltage of power supply III (4) is 56V; The control computer (1) includes an acquisition control module, and the functions of the acquisition control module are: controlling the beam switching of the phased array antenna (5), and performing two-dimensional image acquisition and storage; The second step is to warm up and stabilize the working state Perform the power-on preheating and stabilization operation, set the required voltage value, and connect to the corresponding bias port; wait for the millimeter-wave radiometer (2), the three DC power supplies and the phased array antenna (5) to work in a stable state, carry out the test process; The third step determines the number of scanning points and coordinates Determine the azimuth and elevation coordinates of the scanned image of the millimeter-wave radiometer (2) according to the scanning interval angle; set the scanning interval as θ, and the azimuth and elevation scan angle ranges as α and β respectively; then the azimuth and elevation scans are The number of points m and n are respectively

Wherein [] means round down; the coordinates of each point are

The fourth step is to calibrate the millimeter wave radiometer (2) and the phased array antenna (5) by the acquisition control module The acquisition control module calibrates the millimeter wave radiometer (2) and the phased array antenna (5); aligns the phased array antenna (5) with a 70°C high temperature constant temperature source, and collects the 70°C high temperature constant temperature source calibration data vecHot[mn ]; then align the phased array antenna (5) at the -10°C low temperature constant temperature source, and collect the -10°C low temperature constant temperature source calibration data vecCold[mn]; obtain the low temperature average value:

AveCold: low temperature average; vecCold[i]: the i-th low temperature value; The average value of the difference between high temperature and low temperature:

DiffAve: the average value of the difference between high temperature and low temperature; vecHot[i]: high temperature value of the i-th road; The fifth step is to calibrate the target image Collect the target image, obtain the image data OriginalData[mn], and finally perform calibration compensation on the target image, and perform separate compensation for each millimeter-wave radiometer (2) point:

CompensateData[i]: The data after the i-th internal calibration compensation; OriginalData[i]: The data before the i-th internal calibration compensation; AveCold: low temperature average; DiffAve: the average value of the difference between high temperature and low temperature; Finally, the CompensateData[i] is synthesized to obtain the compensated data CompensateData[mn], and the internal calibration is completed.

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