Radar target precise tracking method based on pointing control bias

Abstract

The present application relates to a kind of radar target accurate tracking method of pointing control bias, belong to tracking radar technical field.The method includes: the formation of angle-measuring signal, pointing control bias quantity formation.The angle-measuring signal formation step includes, antenna plane is divided into 4 quadrant subarray, and is received respectively, AD sampling, DDC, forms and difference signal.Pointing bias quantity formation step includes, the region in beam width is divided, and is divided into low signal-to-noise ratio area, high signal-to-noise ratio area, according to the position of area division, pointing bias quantity selection is carried out.The tracking angle of the present application is by adjusting alignment pointing bias to realize accurate tracking, it is a process with closed-loop control and measurement, with the advantages of fast iteration speed, high convergence precision.The present application solves the problem that the angle-measuring precision of existing tracking radar under low signal-to-noise ratio condition deteriorates, even can lead to angle-measuring value periodic flip jump around true value.

Description

Technical Field

[0001] This invention relates to the field of tracking radar technology, and in particular to a method for precise radar target tracking based on pointing control bias. Background Technology

[0002] Tracking radar is a type of radar capable of continuously tracking targets and measuring their coordinates. Using tracking radar, precise measurement parameters of the target's continuous motion trajectory can be obtained. Based on the coordinate measurements of the tracked target, the tracking radar's antenna beam can always be pointed at the target, thus providing continuous target coordinate measurement information. Angular measurement accuracy is a crucial performance indicator for tracking radar and a significant factor influencing the construction of more advanced systems.

[0003] Target angle measurement commonly employs the two-dimensional sum-difference angle measurement method. The typical approach involves dividing the antenna array into four beams and using these beams to form sum, azimuth, and elevation difference channels. Observing and calculating the signals from these channels yields the target's deviation angle from the beam center. This method offers high accuracy and low computational complexity, making it widely used in engineering. However, it is limited by the signal-to-noise ratio (SNR). Especially as the target gets closer to the radar antenna's pointing center, the signal strength in the difference channels decreases, leading to a worse SNR for angle measurement. This not only affects the accuracy of target angle measurement but also causes the radar antenna to fail to accurately align with the target under low SNR conditions. It can even cause the measured angle value to periodically fluctuate around the true value. Summary of the Invention

[0004] The technical problem to be solved by this invention is:

[0005] To avoid the shortcomings of existing technologies, this invention provides a radar target precision tracking method based on pointing control bias, which solves the problem that the angle measurement accuracy of existing tracking radars deteriorates under low signal-to-noise ratio conditions, and may even cause the angle measurement value to periodically flip and jump around the true value.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A radar target precision tracking method based on pointing control bias, characterized by comprising:

[0008] Acquire signals from the pitch difference channel, elevation difference channel, and azimuth difference channel;

[0009] The ratio of the elevation difference channel to the sum channel is calculated based on the sum channel and the elevation difference channel. The elevation angle measurement of the target's deviation from the beam center is calculated based on the ratio of the elevation difference channel to the sum channel. The elevation angle measurement of the target in the radar antenna coordinate system is calculated based on the elevation angle measurement of the target's deviation from the beam center.

[0010] The ratio of the azimuth difference channel to the sum channel is calculated based on the sum channel and the azimuth difference channel. The azimuth angle measurement of the target's deviation from the beam center is calculated based on the ratio of the azimuth difference channel to the sum channel. The azimuth angle measurement of the target in the radar antenna coordinate system is calculated based on the azimuth angle measurement of the target's deviation from the beam center.

[0011] The pointing offset is determined based on the target's elevation and azimuth measurements in the radar antenna coordinate system, with the offset amount selected as 0.2 beamwidths; the controlling pointing position is:

[0012]

[0013]

[0014] in, For pitch control pointing position, The elevation angle of the target in the radar antenna coordinate system is the measured value. The elevation beamwidth is 3dB. This is the azimuth control pointing position. The azimuth angle measurement of the target in the radar antenna coordinate system. The azimuth beamwidth is 3dB.

[0015] A further technical solution of the present invention: pointing offset is performed based on the elevation angle measurement value and azimuth angle measurement value of the target in the radar antenna coordinate system, through 2-3 iterations.

[0016] A further technical solution of the present invention: the acquisition of the pitch difference channel, azimuth difference channel signals includes:

[0017] The antenna plane is divided into four quadrants: subarray 1, subarray 2, subarray 3, and subarray 4.

[0018] The radio frequency signal output from the antenna plane is received and converted into four corresponding intermediate frequency signals after passing through the receiver.

[0019] The four intermediate frequency signals are sampled using an AD converter to obtain the corresponding four digital intermediate frequency signals.

[0020] The four digital intermediate frequency signals are digitally down-converted to output the corresponding four digital baseband signals.

[0021] The sum and difference operations are performed on these four digital baseband signals to obtain the sum channel, pitch difference channel, and azimuth difference channel signals.

[0022] A further technical solution of the present invention: The elevation angle measurement value of the target's deviation from the beam center is calculated based on the ratio of the elevation difference channel to the sum channel, using the following formula:

[0023]

[0024] in, It is a functional relationship. This is the ratio of the pitch difference channel to the sum channel.

[0025] A further technical solution of the present invention: the elevation angle measurement of the target in the radar antenna coordinate system based on the elevation angle measurement value of the target deviating from the beam center is calculated using the following formula:

[0026]

[0027] in, This refers to the measured elevation angle of the target in the radar antenna coordinate system.

[0028] A further technical solution of the present invention: the azimuth angle measurement value of the target's deviation from the beam center is calculated based on the ratio of the azimuth difference channel to the sum channel, using the following formula:

[0029]

[0030] in, G It is a functional relationship. This is the ratio of the azimuth difference channel to the sum channel.

[0031] A further technical solution of the present invention: the azimuth angle measurement of the target in the radar antenna coordinate system based on the azimuth angle measurement value of the target's deviation from the beam center is calculated using the following formula:

[0032]

[0033] in, This refers to the azimuth angle measurement of the target in the radar antenna coordinate system.

[0034] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0035] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0036] A computer program product is characterized by including computer-executable instructions, which, when executed, are used to implement the above-described method.

[0037] The beneficial effects of this invention are as follows:

[0038] The present invention provides a radar target precision tracking method based on pointing control bias, which has the following advantages compared with the prior art:

[0039] 1. The angle measurement signal formation process uses a common radar subarray division, which is easy to implement;

[0040] 2. By controlling the offset of the pointing, the radar antenna can stably provide angle measurement values ​​with a high signal-to-noise ratio, thus ensuring the accuracy of the angle measurement;

[0041] 3. The selected fitted line intersects the theoretical curve at an offset position, which greatly reduces the amount of calculation and storage while ensuring accurate angle measurement;

[0042] 4. The tracking angle measurement of the present invention achieves accurate tracking by adjusting the alignment and pointing offset. It is a process that combines closed-loop control and measurement, and has the advantages of fast iteration speed and high convergence accuracy. Attached Figure Description

[0043] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0044] Figure 1 This is a schematic diagram of the equipment composition for the automated testing method of phase trimming phase array antennas according to the present invention.

[0045] Figure 2 This is the division of the offset interval for the target tracking angle in this invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0047] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0048] This invention provides a radar target precision tracking method based on pointing control offset, the implementation of which includes: the formation of angle measurement signals and the formation of pointing control offset.

[0049] The angle measurement signal formation step includes dividing the antenna plane into four quadrant subarrays and performing reception, AD sampling, DDC (digital down-conversion), and forming sum and difference signals respectively. The pointing offset formation step includes dividing the region within the beamwidth into low signal-to-noise ratio (SNR) and high SNR regions, and selecting the pointing offset based on the region division position.

[0050] Preferably, the system control performs multiple angle measurements based on the angle measurement results. After 2 to 3 iterations, it can stably converge at the pointing offset position to ensure the signal-to-noise ratio of the angle measurement.

[0051] Preferably, in order to reduce the amount of computation, the present invention selects the intersection of the fitted straight line and the theoretical curve at a position with a directional offset, which can reduce the amount of computation while ensuring the accuracy of angle measurement.

[0052] To enable those skilled in the art to better understand the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0053] refer to Figure 1 As shown, this embodiment provides a method for acquiring an angle measurement input signal. The equipment involved in this method includes: an antenna plane 10, a receiver 20, an AD sampling device 30, a digital down-conversion device 40, a channel 50, an elevation difference channel 60, and an azimuth difference channel 70.

[0054] refer to Figure 2 As shown, the method involves the selection of tracking convergence points, including: theoretical angle measurement curve 80, selected angle measurement line 90, low signal-to-noise ratio region 100, and high signal-to-noise ratio region 110.

[0055] The radar target precision tracking method based on pointing control bias provided in this embodiment requires dividing the antenna plane 10 into four quadrants: subarray 1, subarray 2, subarray 3, and subarray 4. The radio frequency signals output from the antenna plane 10 are received and converted into four corresponding intermediate frequency (IF) signals after passing through the receiver 20. The four IF signals are then sampled using an AD sampling 30 to obtain four corresponding digital IF signals. These four digital IF signals are then digitally downconverted using a digital downconversion 40 to output four corresponding digital baseband signals. Finally, the four digital baseband signals are subjected to sum and difference operations to obtain the sum channel 50, elevation difference channel 60, and azimuth difference channel 70.

[0056] Among them, channel 50 corresponds to the sum of 4 channels, identified as S(1+2+3+4) or S all The complex digital signals of each channel output by the digital downconverter 40 are then subjected to the following operations: The pitch difference of 60 corresponds to the difference between the combined upper two subarrays and the combined lower two subarrays, denoted as S(1+2-3-4) or S ele The complex digital signals of each channel output by the digital downconverter 40 are then subjected to the following operations: The azimuth difference of 70 corresponds to the difference between the sum of the two left subarrays and the sum of the two right subarrays, denoted as S(1-2-3+4) or S. azi The complex digital signals of each channel output by the digital downconverter 40 are then subjected to the following operations: .

[0057] The deviation angle of the target leaving the beam center and S all S ele S azi There is a functional mapping relationship, which will form a theoretical angle measurement curve of 80°. If the traditional antenna's mechanical scanning method is used, this curve only corresponds to the deviation angle of the target leaving the beam center ( , Related to; if a two-dimensional phased array antenna is used for electronic scanning, if this curve, apart from the deviation angle between the target and the beam center ( , Besides being related to the beam pointing (ele, azi), it is also related to the beam direction. Here we consider the more complex electrical scanning method of a two-dimensional phased array antenna.

[0058] The ratio of the pitch difference channel to the sum channel is used Indicates. Corresponds Figure 1 The measured values ​​obtained from the implementation are:

[0059] =

[0060] The theoretical value is

[0061]

[0062] in, It is a functional relationship.

[0063] In the above, ele and azi are known wave position control variables, therefore It represents a one-to-one mapping relationship.

[0064] That is, it can be found using an inverse function. .

[0065] Correspondence with Figure 1 The measured values ​​obtained can be used to determine the elevation angle of the target's deviation from the center of the antenna beam.

[0066]

[0067] Based on the above results, the elevation angle of the target in the radar antenna coordinate system can be calculated as follows:

[0068]

[0069] Similarly, the azimuth angle measurement of the target in the radar antenna coordinate system can be obtained as follows:

[0070] ,in , =

[0071] in, The measured azimuth angle of the target's deviation from the center of the antenna beam. It represents a functional relationship.

[0072] refer to Figure 2 As shown, in order to solve the problem that the angle measurement accuracy of the existing tracking radar deteriorates under low signal-to-noise ratio conditions, and may even cause the angle measurement value to periodically flip and jump around the true value, the radar is divided into a low signal-to-noise ratio region 100 and a high signal-to-noise ratio region 110 according to the degree of deviation of the target from the beam center.

[0073] When selecting, the normalized beamwidth away from the beam center The region is a low signal-to-noise ratio zone of 100; the normalized beamwidth away from the beam center is... , The region is a high signal-to-noise ratio region, 110.

[0074] When the target appears in the low signal-to-noise ratio (SNR) region (100°), and the target is directly facing the beam center, although the SNR of the relative channel signal is the best, the SNR of the differential channel signal is the worst. When the relative channel SNR is weak, the differential channel signal will be submerged in system noise, thus making it impossible to... , Perform accurate calculations.

[0075] When the target appears in the high signal-to-noise ratio region 110, and the target deviates from the beam center, a significant improvement in the signal-to-noise ratio of the poor channel signal is achieved by trading a decrease of no more than 3dB in the attenuation of the main channel signal, making the target more effective. , Accurate calculations are now possible.

[0076] A key aspect of this invention is that, based on the target angle measurement value... , A pointing offset is applied, with the offset amount selected as 0.2 beamwidths. That is, the system control is based on the measured value. , Based on this, accurately control the beam pointing position deviating from the beam center, and control the pointing position as follows:

[0077]

[0078]

[0079] in, Indicates 3dB pitch beamwidth, This indicates the 3dB azimuth beamwidth.

[0080] Under pointing control bias conditions, the system control typically converges the beam pointing to a position with an bias of 0.2 beamwidths through two pointing iterations. In some poorer random scenarios, where the target randomly appears once in the low SNR region 100, the beam pointing can quickly escape the low SNR region 100 and converge into the high SNR region 110 due to the pointing bias of the system control. In this case, the cumulative number of system control iterations does not exceed three.

[0081] More preferably, to reduce computational and storage requirements during implementation, a straight line 90 with a slope of k can be used to fit the theoretical angle measurement curve 80. Another key point of this invention is that the selected fitting angle measurement line 90 should coincide with the theoretical angle measurement curve 80 within 0.2 beamwidths. The significant benefit of doing so is that even if the selected angle measurement line 90 deviates from the theoretical angle measurement curve 80 to varying degrees, because the curve is monotonic, the results of multiple iterations will still fall within the designed 0.2 beamwidth.

[0082] The angle measurement results at the convergence position are pre-designed and therefore do not deviate significantly from the theoretical true angle measurement value, thus ensuring the accuracy of radar tracking angle measurement.

[0083] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A method for precise radar target tracking based on pointing control offset, characterized in that, include: Acquire signals from the pitch difference channel, elevation difference channel, and azimuth difference channel; The ratio of the pitch difference channel to the sum channel is calculated based on the sum channel and the pitch difference channel. The pitch angle measurement value of the target's deviation from the beam center is calculated based on the ratio of the pitch difference channel to the sum channel. Calculate the target's elevation angle in the radar antenna coordinate system based on the elevation angle measurement value of the target's deviation from the beam center; The ratio of the azimuth difference channel to the sum channel is calculated based on the sum channel and the azimuth difference channel. The azimuth angle measurement of the target's deviation from the beam center is calculated based on the ratio of the azimuth difference channel to the sum channel. Calculate the target's azimuth angle in the radar antenna coordinate system based on the azimuth angle measurement of the target's deviation from the beam center; The pointing offset is determined based on the target's elevation and azimuth measurements in the radar antenna coordinate system, with the offset amount selected as 0.2 beamwidths; the controlling pointing position is: in, For pitch control pointing position, The elevation angle of the target in the radar antenna coordinate system is the measured value. The elevation beamwidth is 3dB. This is the azimuth control pointing position. The azimuth angle measurement of the target in the radar antenna coordinate system. The azimuth beamwidth is 3dB.

2. The radar target precision tracking method based on pointing control offset according to claim 1, characterized in that, The pointing offset is determined based on the elevation and azimuth measurements of the target in the radar antenna coordinate system, through 2-3 iterations.

3. The radar target precision tracking method based on pointing control offset according to claim 1, characterized in that, The acquisition of the pitch difference channel, azimuth difference channel signals includes: The antenna plane is divided into four quadrants: subarray 1, subarray 2, subarray 3, and subarray 4. The radio frequency signal output from the antenna plane is received and converted into four corresponding intermediate frequency signals after passing through the receiver. The four intermediate frequency signals are sampled using an AD converter to obtain the corresponding four digital intermediate frequency signals. The four digital intermediate frequency signals are digitally down-converted to output the corresponding four digital baseband signals. The sum and difference operations are performed on these four digital baseband signals to obtain the sum channel, pitch difference channel, and azimuth difference channel signals.

4. The radar target precision tracking method based on pointing control offset according to claim 1, characterized in that, The elevation angle measurement value of the target's deviation from the beam center is calculated based on the ratio of the elevation difference channel to the sum channel, using the following formula: in, It is a functional relationship. This is the ratio of the pitch difference channel to the sum channel.

5. The radar target precision tracking method based on pointing control offset according to claim 4, characterized in that, The elevation angle measurement of the target in the radar antenna coordinate system is calculated based on the elevation angle measurement value of the target's deviation from the beam center, using the following formula: in, This refers to the measured elevation angle of the target in the radar antenna coordinate system.

6. The radar target precision tracking method based on pointing control offset according to claim 1, characterized in that, The azimuth angle measurement of the target's deviation from the beam center is calculated based on the ratio of the azimuth difference channel to the sum channel, using the following formula: in, G It is a functional relationship. This is the ratio of the azimuth difference channel to the sum channel.

7. The radar target precision tracking method based on pointing control offset according to claim 6, characterized in that, The calculation of the target's azimuth angle in the radar antenna coordinate system based on the target's deviation from the beam center is performed using the following formula: in, This refers to the azimuth angle measurement of the target in the radar antenna coordinate system.

8. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of claim 1.

9. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method of claim 1.

10. A computer program product, characterized in that... It includes computer-executable instructions, which, when executed, are used to implement the method of claim 1.

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