Method for testing maximum radar detection distance of small unmanned aerial vehicle target

Abstract

The invention discloses a method for testing the maximum radar detection distance of a small unmanned aerial vehicle target. Comprising the steps of setting an erection position of a radar antenna and a target route, and determining a beam path; determining the erection position of a radar antenna; selecting the direction of a target route of the small unmanned aerial vehicle; checking whether a beam channel is obviously influenced by a stable shielding object or not; checking whether obvious cloud, rain, fog, hail and dust exist in a beam path of a radar detection target; checking the false alarm probability of the noise; starting an emission function, and adjusting a constant false alarm threshold, a detection threshold and a moving target processing parameter to achieve a state of obviously detecting the target; opening a target trace point track recording function; the target small unmanned aerial vehicle sails according to a planned route, and the radar detects the target. According to the invention, the test result of the maximum radar detection distance of the small unmanned aerial vehicle target is reasonable and stable.

Description

Technical Field

[0001] This invention belongs to the field of radar target detection range testing technology, and in particular relates to a test method for the maximum radar detection range of small unmanned aerial vehicle targets. Background Technology

[0002] With the development of small unmanned aerial vehicle (UAV) technology, their excellent flexibility, low cost, and small RCS have led to their widespread application in both battlefield and civilian fields. The maximum radar detection range of small UAV targets has become a basic specification for almost every type of radar.

[0003] The maximum radar detection range test of small UAV targets often shows an unstable state. Even when the radar equipment is installed in the same position and the altitude, speed and route of the small UAV are unchanged, the maximum detection range often fluctuates by more than 30%.

[0004] Therefore, there is an urgent need for an experimental method to determine the maximum radar detection range of small unmanned aerial vehicle targets, in order to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a test method for the maximum radar detection range of small unmanned aerial vehicles (UAVs), which achieves reasonable and stable test results for the maximum radar detection range of small UAVs.

[0006] To achieve the objective of this invention, a test method for the maximum radar detection range of a small unmanned aerial vehicle (UAV) target is provided, comprising the following steps:

[0007] Step 1: Set the installation location of the radar antenna and the target route, and determine the beam path based on the radar-related parameters, the set installation location of the radar antenna, and the position in the target route.

[0008] Step 2: Visually observe the area near the radar antenna installation location to determine the radar antenna installation plan; for other areas, determine the radar antenna installation location using the radar line-of-sight distance formula.

[0009] Step 3: Based on the radar antenna installation location and the beam path, select the direction of the target flight path of the small UAV. In the near zone of the radar antenna, visual inspection is used, and in the far zone, the beam path data is used to determine whether there is a large area of ​​water or flat ground in the beam line of sight that may affect beam transmission. If so, the target flight path is changed to another location with the radar antenna as the center until the requirements are met.

[0010] Step 4: Based on the adjusted target route, check whether there are any obvious stable obstructions on the beam channel according to the beam path. If so, change the target route to another position with the radar antenna as the center until there are no obvious stable obstructions.

[0011] Step 5: Based on the adjusted target route without the influence of the aforementioned stable obstructions, check whether there are obvious clouds, rain, fog, hail, or sandstorms in the radar beam path for detecting the target. If there are obvious clouds, rain, fog, hail, or sandstorms, wait until they disappear before conducting the test.

[0012] Step 6: Before the formal test, turn on the radar and check the false alarm probability of noise in the ready-to-transmit state. Adjust the noise floor limit value to meet the false alarm probability requirements. If the false alarm rate is too high, increase the noise floor limit value. If the false alarm rate is too low, decrease the noise floor limit value.

[0013] Step 7: Activate the transmission function and adjust the constant false alarm rate (CFAR) threshold, detection threshold, and moving target processing parameters to achieve a state where the target is clearly detected. If clutter is too high, increase the above parameters; if the target echo is too weak and makes it difficult to detect the target, decrease the above parameters. The CFAR module is used to extract useful radar echoes through radar echo amplitude thresholds. Radar echoes below the set value are treated as clutter, while radar echoes above the set threshold are used for target detection. The detection threshold is used for target point extraction. Points with amplitude values ​​higher than the set value after aggregation are considered target points, while those below the set value are considered clutter. The moving target processing module is used to extract targets through radar echo velocity thresholds. Echoes below the set threshold are defined as clutter, and echoes above the set value are defined as target echoes.

[0014] Step 8: Enable the target point track recording function to record the target point and target track information in real time after the radar has processed the data;

[0015] Step 9: The target small drone flies along the planned route, and the radar detects the target.

[0016] Step 1 specifically includes the following steps:

[0017] Step 1-1: Collect observation parameters, including radar radio frequency wavelength, actual width of radar antenna in azimuth beamwidth plane, actual width of radar antenna in elevation beamwidth plane, angle between the beam center direction and the azimuth plane of radar antenna normal direction, angle between the beam center direction and the elevation plane of radar antenna normal direction, and distance between any point on the line connecting radar antenna center and target center and antenna center.

[0018] Step 1-2: Calculate the effective width of the radar antenna in the azimuth direction using the formula for calculating the projection length of the beam pointing vertical plane, taking the actual width of the radar antenna in the azimuth beamwidth plane and the angle between the beam center direction and the azimuth plane of the radar antenna normal direction.

[0019] Steps 1-3: Calculate the effective width of the radar antenna in the elevation direction using the formula for calculating the projection length of the beam pointing vertical plane, taking the actual width of the radar antenna in the elevation beamwidth plane and the angle between the beam center direction and the elevation plane normal direction.

[0020] Steps 1-4: The radar radio frequency wavelength and the effective width of the radar antenna in the azimuth width direction are used to obtain the azimuth beam 3dB width using the two-dimensional beamwidth calculation formula of a uniform rectangular surface.

[0021] Steps 1-5: Using the radar radio frequency wavelength and the actual width of the radar antenna in the beam elevation plane, the 3dB width of the elevation beam is obtained by applying the two-dimensional beam width calculation formula for a uniform rectangular surface.

[0022] Steps 1-6: Using trigonometric formulas, obtain the beam channel radius at any point on the line connecting the radar RF wavelength, the distance from the antenna center to any point on the line connecting the radar antenna center and the target center, the 3dB width of the azimuth beam, and the 3dB width of the elevation beam.

[0023] Steps 1-2 are specifically shown in the following formula:

[0024] ;

[0025] in, The effective width of the radar antenna in the azimuth beamwidth direction is expressed in meters. The actual width of the radar antenna in the azimuth beam direction plane is expressed in meters. The angle between the beam center direction and the azimuth plane of the radar antenna normal direction is expressed in degrees.

[0026] Steps 1-3 are specifically shown in the following formula:

[0027] ;

[0028] in, The effective width of the radar antenna in the beam elevation direction is expressed in meters. The actual width of the radar antenna in the beam elevation plane, in meters; The angle between the beam center direction and the elevation direction of the radar antenna normal is expressed in degrees.

[0029] Steps 1-4 are specifically shown in the following formula:

[0030] ;

[0031] in, The beamwidth is 3dB in the azimuth direction, and its dimension is degrees. The radar radio frequency wavelength has the dimension of meters. Let be the effective width of the radar antenna in the azimuth direction, with the dimension of meters.

[0032] Steps 1-5 are specifically shown in the following formula:

[0033] ;

[0034] in, The elevation beamwidth is 3dB, and its dimension is degrees. The radar radio frequency wavelength has the dimension of meters. Let be the effective width of the radar antenna in the elevation direction, with the dimension of meters.

[0035] Steps 1-6 are specifically shown in the following formula:

[0036] ;

[0037] Where r is the beam radius at any point on the line connecting the radar antenna center and the target center, with the distance from the antenna center being R, and the dimension is meters; R is the distance from any point on the line connecting the radar antenna center and the target center, with the dimension is meters. The beam radius is half the beamwidth and has the dimension of degrees. If the azimuth beamwidth is 3dB, then r is the azimuth radius of any point on the line connecting the radar antenna center and the target center, which is R away from the antenna center. If the elevation beamwidth is 3dB, then r is the elevation radius of any point on the line connecting the radar antenna center and the target center, at which the distance from the antenna center is R.

[0038] The specific formula for the radar line-of-sight distance in step 2 is as follows:

[0039] ;

[0040] Where D is the line-of-sight distance, with the dimension of kilometers; It is the center height of the radar antenna, with the dimension of meters; The target height is measured in meters.

[0041] A computer program product includes computer program instructions that, when executed on a computer, cause the computer to perform the above-described experimental method for determining the maximum radar detection range of a small unmanned aerial vehicle (UAV) target.

[0042] Compared with existing technologies, the significant advancements of this invention lie in the following: Addressing the instability of maximum detection range test results, this invention employs the following research and measures: First, ensuring clear visibility conditions, including not only the visibility around the radar but also around the target and the intermediate area between the radar and the target; considering not only the influence of stable obstructions such as trees, mountains, buildings, and vehicles, but also minimizing the influence of meteorological obstructions such as clouds, rain, fog, hail, and sandstorms. Second, avoiding the influence of subrefractive environments on the test; third, taking measures to minimize the impact of significant multipath effects, particularly in marine or lake environments. In summary, this invention achieves reasonable and stable test results for the maximum radar detection range of small unmanned aerial vehicles (UAVs).

[0043] To more clearly illustrate the functional characteristics and structural parameters of the present invention, further explanation is provided below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0045] Figure 1 This is a schematic diagram illustrating the effect of non-uniform space on electromagnetic waves.

[0046] Figure 2 This is a longitudinal cross-sectional view of the radar radiation beam of the present invention;

[0047] Figure 3 This is a flowchart of the steps of the present invention. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention provides an experimental method for determining the maximum radar detection range of a small unmanned aerial vehicle (UAV) target, combined with... Figure 3 This includes the following steps:

[0050] Step 1: Set the radar antenna installation location and target flight path, and determine the beam path based on relevant radar parameters, the set radar antenna installation location, and the target flight path; for example... Figure 2As shown, it consists of a main lobe and multiple sublobes, with each lobe representing a beam path; the horizontal axis represents the distance of the detection space relative to the center of the radar antenna, the vertical axis represents the height of the detection space relative to the center of the radar antenna, and the values ​​marked on the right and top are the elevation angles of the detection space relative to the center of the radar antenna.

[0051] Step 2: Visually observe the area near the radar antenna installation location to determine the radar antenna installation plan; for other areas, determine the radar antenna installation location using the radar line-of-sight distance formula.

[0052] Step 3: Based on the radar antenna installation location and the beam path, select the direction of the target flight path of the small UAV. In the near zone of the radar antenna, visual inspection is used, and in the far zone, the beam path data is used to determine whether there is a large area of ​​water or flat ground in the beam line of sight that may affect beam transmission. If so, the target flight path is changed to another location with the radar antenna as the center until the requirements are met.

[0053] Step 4: Based on the adjusted target route, check whether there are any obvious stable obstructions on the beam channel according to the beam path. If so, change the target route to another position with the radar antenna as the center until there are no obvious stable obstructions.

[0054] Step 5: Based on the adjusted target route without the influence of the aforementioned stable obstructions, check whether there are obvious clouds, rain, fog, hail, or sandstorms in the radar beam path for detecting the target. If there are obvious clouds, rain, fog, hail, or sandstorms, wait until they disappear before conducting the test.

[0055] Step 6: Before the formal test, turn on the radar and check the false alarm probability of noise in the ready-to-transmit state. Adjust the noise floor limit value to meet the false alarm probability requirements. If the false alarm rate is too high, increase the noise floor limit value. If the false alarm rate is too low, decrease the noise floor limit value.

[0056] Step 7: Activate the transmission function and adjust the constant false alarm rate (CFAR) threshold, detection threshold, and moving target processing parameters to achieve a state where the target is clearly detected. If clutter is too high, increase the above parameters; if the target echo is too weak and makes it difficult to detect the target, decrease the above parameters. The CFAR module is used to extract useful radar echoes through radar echo amplitude thresholds. Radar echoes below the set value are treated as clutter, while radar echoes above the set threshold are used for target detection. The detection threshold is used for target point extraction. Points with amplitude values ​​higher than the set value after aggregation are considered target points, while those below the set value are considered clutter. The moving target processing module is used to extract targets through radar echo velocity thresholds. Echoes below the set threshold are defined as clutter, and echoes above the set value are defined as target echoes.

[0057] Step 8: Enable the target point track recording function to record the target point and target track information in real time after the radar has processed the data;

[0058] Step 9: The target small drone flies along the planned route, and the radar detects the target.

[0059] Step 1 specifically includes the following steps:

[0060] Step 1-1: Collect observation parameters, including radar radio frequency wavelength, actual width of radar antenna in azimuth beamwidth plane, actual width of radar antenna in elevation beamwidth plane, angle between the beam center direction and the azimuth plane of radar antenna normal direction, angle between the beam center direction and the elevation plane of radar antenna normal direction, and distance between any point on the line connecting radar antenna center and target center and antenna center.

[0061] Step 1-2: Calculate the effective width of the radar antenna in the azimuth direction using the formula for calculating the projection length of the beam pointing vertical plane, taking the actual width of the radar antenna in the azimuth beamwidth plane and the angle between the beam center direction and the azimuth plane of the radar antenna normal direction.

[0062] Steps 1-3: Calculate the effective width of the radar antenna in the elevation direction using the formula for calculating the projection length of the beam pointing vertical plane, taking the actual width of the radar antenna in the elevation beamwidth plane and the angle between the beam center direction and the elevation plane normal direction.

[0063] Steps 1-4: The radar radio frequency wavelength and the effective width of the radar antenna in the azimuth width direction are used to obtain the azimuth beam 3dB width using the two-dimensional beamwidth calculation formula of a uniform rectangular surface.

[0064] Steps 1-5: Using the radar radio frequency wavelength and the actual width of the radar antenna in the beam elevation plane, the 3dB width of the elevation beam is obtained by applying the two-dimensional beam width calculation formula for a uniform rectangular surface.

[0065] Steps 1-6: Using trigonometric formulas, obtain the beam channel radius at any point on the line connecting the radar RF wavelength, the distance from the antenna center to any point on the line connecting the radar antenna center and the target center, the 3dB width of the azimuth beam, and the 3dB width of the elevation beam.

[0066] Steps 1-2 are specifically shown in the following formula:

[0067] ;

[0068] in, The effective width of the radar antenna in the azimuth beamwidth direction is expressed in meters. The actual width of the radar antenna in the azimuth beam direction plane is expressed in meters. The angle between the beam center direction and the azimuth plane of the radar antenna normal direction is expressed in degrees.

[0069] Steps 1-3 are specifically shown in the following formula:

[0070] ;

[0071] in, The effective width of the radar antenna in the beam elevation direction is expressed in meters. The actual width of the radar antenna in the beam elevation plane, in meters; The angle between the beam center direction and the elevation direction of the radar antenna normal is expressed in degrees.

[0072] Steps 1-4 are specifically shown in the following formula:

[0073] ;

[0074] in, The beamwidth is 3dB in the azimuth direction, and its dimension is degrees. The radar radio frequency wavelength has the dimension of meters. Let be the effective width of the radar antenna in the azimuth direction, with the dimension of meters.

[0075] Steps 1-5 are specifically shown in the following formula:

[0076] ;

[0077] in, The elevation beamwidth is 3dB, and its dimension is degrees. The radar radio frequency wavelength has the dimension of meters. Let be the effective width of the radar antenna in the elevation direction, with the dimension of meters.

[0078] Steps 1-6 are specifically shown in the following formula:

[0079] ;

[0080] Where r is the beam radius at any point on the line connecting the radar antenna center and the target center, with the distance from the antenna center being R, and the dimension is meters; R is the distance from any point on the line connecting the radar antenna center and the target center, with the dimension is meters. The beam radius is half the beamwidth and has the dimension of degrees. If the azimuth beamwidth is 3dB, then r is the azimuth radius of any point on the line connecting the radar antenna center and the target center, which is R away from the antenna center. If the elevation beamwidth is 3dB, then r is the elevation radius of any point on the line connecting the radar antenna center and the target center, at which the distance from the antenna center is R.

[0081] The specific formula for the radar line-of-sight distance in step 2 is as follows:

[0082] ;

[0083] Where D is the line-of-sight distance, with the dimension of kilometers; It is the center height of the radar antenna, with the dimension of meters; The target height is measured in meters.

[0084] Example

[0085] The determination of the radar installation location and the calculation of the radar flight altitude are performed through examples. Assume the radar antenna installation height is 4 meters, and the small UAV target flight altitude is 289 meters.

[0086] Assuming the wavelength of the radio frequency electromagnetic wave at the radar center frequency is 0.03 meters, the radar antenna azimuth width is 3 meters, the elevation width is 0.5 meters, the angle between the elevation beam centerline and the antenna normal is 5°, and the angle between the azimuth beam centerline and the antenna normal is 0°, according to the calculation formula in step 1, we get:

[0087] The effective width of the radar antenna in the beam elevation direction is 0.498 meters;

[0088] The pitch beamwidth is 3.072° (3dB) and the half-beamwidth is 1.536°.

[0089] According to step 2, the radar's line-of-sight range to the target is calculated to be 77.9 kilometers using the traditional method.

[0090] The calculation is performed according to the method of the present invention as follows:

[0091] Assuming the maximum distance to the target small UAV is 10 kilometers, the beam radius at 10 kilometers, calculated using the formula in step 1.6, is 268 meters. The effective target flight altitude should be calculated as 289 - 268 = 21 meters. According to step 2, the radar's line-of-sight range to this target is 27.43 kilometers.

[0092] According to the radar line-of-sight calculation formula in step 2, the minimum flight altitude of the target is calculated to be 0.193 meters. Therefore, the minimum flight altitude of the target at 10 kilometers should be 268.193 meters to ensure that the 3dB beam channel is not blocked.

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A test method for maximum radar detection range of a small unmanned aerial vehicle target, characterized in that, The method comprises the following steps: Step 1, setting up the erection position of the radar antenna and the target route, and determining the beam path according to the radar related parameters, the set up erection position of the radar antenna and the position in the target route; Step 2, determining the radar antenna erection scheme by visually observing the area near the erection position of the radar antenna, and determining the erection position of the radar antenna in other areas by the radar visibility distance formula; Step 3, selecting the direction of the target route of the small unmanned aerial vehicle according to the erection position of the radar antenna and the beam path, and determining whether there is a large piece of water surface or flat ground on the beam visibility channel to affect the beam transmission according to the beam path data, if there is, replacing the target route to other directions with the radar antenna as the center until the requirement is met; Step 4, based on the adjusted target route, checking whether there is a significant stable shelter on the beam channel according to the beam path, if there is, replacing the target route to other directions with the radar antenna as the center until there is no significant stable shelter; Step 5, based on the adjusted target route without the influence of the stable shelter, checking whether there is obvious cloud, rain, fog, hail, sandstorm in the beam path of the radar target detection, if there is obvious cloud, rain, fog, hail, sandstorm, waiting until it disappears before carrying out the test; Step 6, before the formal test, the radar is turned on and is in the state of waiting for emission to check the false alarm probability of noise, and the noise limit value is adjusted to meet the requirement of the false alarm probability; if the false alarm rate is too high, the low noise limit value is adjusted to be higher, and if the false alarm rate is too low, the noise limit value is adjusted to be lower; Step 7, opening the emission function, adjusting the constant false alarm threshold, the detection threshold and the moving target processing parameters to the state of obviously detecting the target: if the clutter is too high, the above parameters are adjusted to be higher, and if the target echo is too weak to cause the target to be difficult to be detected, the above parameters are adjusted to be lower; the constant false alarm module is used to extract useful radar echoes through the radar echo amplitude value threshold, the radar echoes below the set value are treated as clutter, and the radar echoes above the set threshold are used for target detection; the detection threshold is used for target track extraction, and the target track is extracted for the track amplitude value above the set value, and the track below the set value is treated as clutter; the moving target processing is used to extract the target through the radar echo corresponding speed threshold, the echo below the set threshold value is defined as clutter, and the echo above the set value is defined as the echo of the target; Step 8, opening the target track recording function, realizing the real-time recording of the target track information and the target track information after the data processing of the radar; Step 9, the target small unmanned aerial vehicle sails according to the planned route, and the radar detects the target.

2. The test method for target maximum radar detection range of a small unmanned aerial vehicle according to claim 1, characterized in that, The step 1 specifically comprises the following steps: Step 1-1, collecting observation parameters, the observation parameters comprising the radar radio frequency wavelength, the actual width of the radar antenna in the azimuth beam width plane, the actual width of the radar antenna in the elevation beam width plane, the azimuth plane included angle between the beam center direction and the normal direction of the radar antenna, the elevation plane included angle between the beam center direction and the normal direction of the radar antenna, the distance between any point on the line connecting the radar antenna center and the target center and the antenna center; Step 1-2, the radar antenna in the azimuth beam width plane actual width, the beam center direction and the radar antenna normal direction azimuth plane angle, through the beam pointing vertical plane projection length calculation formula calculates the radar antenna in the azimuth effective width; Step 1-3, the radar antenna in the elevation beam width plane actual width, the beam center direction and the radar antenna normal direction elevation plane angle, through the beam pointing vertical plane projection length calculation formula calculates the radar antenna in the elevation effective width; Step 1-4, the radar radio frequency wavelength, the radar antenna in the beam azimuth width direction effective width, through the uniform rectangular surface two-dimensional beam width calculation formula obtains the azimuth beam 3dB width; Step 1-5, the radar radio frequency wavelength, the radar antenna in the beam elevation plane actual width, through the uniform rectangular surface two-dimensional beam width calculation formula, obtains the elevation beam 3dB width; Step 1-6, the radar radio frequency wavelength, the distance between the radar antenna center and the target center, the azimuth beam 3dB width, the elevation beam 3dB width, through the triangular formula, obtains the beam channel radius of the radar antenna center and the target center.

3. The test method for target maximum radar detection range of a small unmanned aerial vehicle according to claim 2, characterized in that, The step 1-2 is specifically as follows: ； wherein, is the effective width of the radar antenna in the azimuth beam width direction, dimension: meter; is the actual width of the radar antenna in the azimuth beam direction plane, dimension: meter; is the azimuth plane angle between the beam center direction and the normal direction of the radar antenna, dimension: degree.

4. The test method for target maximum radar detection range of a small unmanned aircraft according to claim 3, characterized in that, The step 1-3 is specifically as follows: ； wherein, is the effective width of the radar antenna in the beam elevation direction, dimension: meter; is the actual width of the radar antenna in the beam elevation plane, dimension: meter; is the angle between the beam center direction and the normal elevation direction of the radar antenna, dimension: degree.

5. The test method for target maximum radar detection range of a small unmanned aircraft according to claim 4, characterized in that, The step 1-4 is specifically as follows: ； wherein, is the 3dB width of the beam azimuth, dimension: degree; is the radar radio frequency wavelength, dimension: meter; is the effective width of the radar antenna in the beam azimuth, dimension: meter.

6. The test method for target maximum radar detection range of a small unmanned aircraft according to claim 5, characterized in that, The step 1-5 is specifically as follows: ； wherein, is the 3dB width of the elevation beam, dimension: degree; is the radar radio frequency wavelength, dimension: meter; is the effective width of the radar antenna in the elevation direction, dimension: meter.

7. The test method for target maximum radar detection range of a small unmanned aircraft according to claim 6, characterized in that, The step 1-6 is specifically as follows: ； Wherein, r is the beam radius at the distance R of any point on the line connecting the radar antenna center and the target center to the antenna center, with the dimension of: meter; R is the distance of any point on the line connecting the radar antenna center and the target center to the antenna center, with the dimension of: meter; is half of the beam width, i.e. the beam radius, with the dimension of: degree. If is the 3dB width of the azimuth beam, r is the beam azimuth radius at the distance R of any point on the line connecting the radar antenna center and the target center to the antenna center; If is the 3dB width of the elevation beam, r is the beam elevation radius at the distance R of any point on the line connecting the radar antenna center and the target center to the antenna center.

8. The test method for target maximum radar detection range of a small unmanned aircraft according to claim 1, characterized in that, The step 2 radar visibility distance formula is specifically as follows: ； Wherein, D is the visual distance, dimension is: kilometer; is the radar antenna center height, dimension is: meter; is the target height, dimension is: meter.

9. The test method for maximum radar detection range of a small unmanned aircraft target according to claim 1, wherein, The stable shelter includes trees, mountains, buildings, vehicles.

10. A computer program product comprising computer program instructions, characterised in that, When the computer program instructions run on the computer, make the computer execute the method as claimed in any one of claims 1 to 9. When the computer program instructions run on the computer, make the computer execute the method as claimed in any one of claims 1 to 9.

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