An outdoor test method for ground radar power testing

Abstract

The present invention discloses an outdoor test method for ground radar power test, the steps are as follows: (1) the RCS of the UAV with a load is obtained by testing in a microwave darkroom in advance; (2) at the beginning of the experiment, the radar antenna far field condition is met and the power of the radar signal is measured; (3) the UAV echo power is calculated according to the UAV RCS data and the radar signal power reaching the receiving antenna surface of the load; (4) the load simulated echo power is adjusted to be equal to the UAV target echo power, at which time the target distance simulated by the load is the experimental distance between the UAV and the radar; (5) the load simulated target distance and echo power are adjusted until the radar just detects the UAV target, thereby obtaining the detection power of the radar to the UAV. The present invention combines the UAV platform and the load to test the power of the ground radar, the test distance only needs to meet the radar antenna far field condition, and the track state is controllable, the test cycle is short, and the cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of radar testing, and in particular relates to an outdoor test method for ground radar power testing. Background Art

[0002] Radar power is the main combat technical indicator of radar, which is characterized by the detection distance of specific RCS targets. The existing ground radar power test method mainly relies on detecting civil aircraft in outdoor venues or conducting special flight inspection tests. The main problem is that the test distance is equivalent to the radar power, generally around a few hundred kilometers. Even if a small drone is used for flight inspection, the test distance is also around a hundred kilometers. At the same time, the use of civil aircraft has problems such as uncertain flight time and uncontrollable track status. Special flight inspection tests have problems such as long coordination cycle and high test cost.

[0003] The shortcomings of existing testing methods not only affect the factory acceptance and delivery cycle of radars to troops, but also fail to meet the troops' urgent need to quickly put ground radar positions into use after maintenance. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to address the deficiencies in the prior art and provide a field test method for testing the power of ground radar, which combines the use of an unmanned aerial vehicle platform and a payload to test the power of the ground radar. The test distance only needs to meet the far-field conditions of the radar antenna, and the track state is controllable, with a short test cycle and low cost.

[0005] Technical solution: To solve the above technical problems, the present invention provides an outdoor test method for ground radar power testing, comprising the following steps:

[0006] Step 1: Test the RCS of the UAV with the payload in a microwave darkroom in advance;

[0007] Step 2: The experiment starts, the far-field conditions of the radar antenna are met, and the power of the radar signal is measured;

[0008] Step 3: Calculate the UAV echo power based on the UAV RCS data and the radar signal power reaching the payload receiving antenna aperture;

[0009] Step 4: Adjust the payload simulation echo power to be equal to the drone target echo power. At this time, the target distance simulated by the payload is the experimental distance between the drone and the radar.

[0010] Step 5: Adjust the payload simulation target distance and echo power until the radar just detects the drone target, and then obtain the radar's detection power for the drone.

[0011] Furthermore, in the experiment in step 2, at the beginning of the experiment, the specific steps of measuring the power of the radar signal when the far-field condition of the radar antenna is met are as follows:

[0012] Step 2.1: The test distance between the drone and the radar should meet the far-field condition of the radar antenna;

[0013] Step 2.2: Obtain the radar power reaching the payload receiving antenna aperture based on the payload measurement.

[0014] Furthermore, the radar antenna far-field conditions satisfied in step 2.1 are as follows:

[0015]

[0016] Where R is the test distance; D is the maximum size of the radar antenna aperture; λ is the radar signal wavelength.

[0017] Furthermore, the specific steps of obtaining the radar power in step 2.2 are as follows: according to the radar signal power Pr reaching the payload receiver interface and the payload antenna gain, the radar signal power P reaching the payload is calculated using the calculation formula:

[0018] P=Pr-G

[0019] Where P and Pr are the radar signal powers reaching the payload antenna aperture and the receiver aperture, respectively, in dBm; G is the payload antenna gain, in dBi.

[0020] Furthermore, in step 3, the specific steps of calculating the drone echo power based on the drone RCS data and the radar signal power reaching the payload receiving antenna aperture are as follows:

[0021] According to the RCS value σ of the UAV after the payload is mounted measured in the microwave darkroom in advance, and the radar signal power reaching the payload antenna aperture, the target echo power of the UAV can be calculated. The calculation formula is as follows:

[0022]

[0023] Among them, P tar is the UAV target echo power, P is the radar signal power reaching the payload antenna aperture, both in W; σ is the UAV RCS value, in m 2 ; A e is the effective aperture of the antenna, and its expression is:

[0024]

[0025] Where G is the antenna gain, unitless; λ is the wavelength, unit is m.

[0026] Furthermore, the specific steps of obtaining the detection power of the radar to the UAV in step 5 are as follows:

[0027] The payload simulates the target's movement trajectory away from the radar, and adjusts the payload simulated target distance and echo power. When the simulated target echo power is reduced to the radar receiving sensitivity, that is, the radar just detects the UAV target, then the payload simulated target distance is the radar's detection power to the UAV.

[0028] The key point of the present invention is to jointly use the UAV platform and the UAV payload to test the power of the ground radar. The target echo power of the UAV to the radar is calculated by the payload measurement. On this basis, the payload simulates the motion trajectory of the UAV platform away from the radar, including simulating the target distance and echo power. When the simulated echo power is just equal to the radar receiving sensitivity, that is, the radar can just detect the target, then the simulated target distance, that is, the detection power of the radar to the UAV target, is equal to the detection power of the radar to the UAV target.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] The present invention combines an unmanned aerial vehicle platform and a payload to test the field test method of the ground radar power. The test distance only needs to meet the far-field conditions of the radar antenna (generally several kilometers), and the test can be carried out in a general field, thereby solving the problem that the test distance of the existing test method needs to be hundreds of kilometers or even thousands of kilometers. The track state is controllable, the test cycle is short, and the cost is low. The factory acceptance and delivery cycle of the radar to the troops can be greatly shortened, and the urgent need of the troops to quickly put the ground radar positions into use after maintenance can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0033] The present invention provides an outdoor test method for ground radar power test. Before the test, the RCS of the UAV with a load is tested in a microwave darkroom. The load has the ability to measure radar signals and can measure the power of radar signals; it has the ability to simulate dynamic target echoes and can simulate the distance, speed and echo power of aerial target echoes. During the test, the load measures the radar radiation power density reaching the UAV and calculates the echo power of the UAV platform returning to the radar; then the target echo simulation capability of the load is used to equivalently simulate the echo power of the UAV platform returning to the radar; by adjusting the simulated echo amplitude, the motion trajectory of the UAV platform away from the radar can be simulated, and the echo power is reduced to the radar receiving sensitivity, that is, the radar can just detect the target. At this time, the target distance simulated by the load is the radar power.

[0034] Specific as Figure 1 As shown, a field test method for ground radar power testing includes the following steps:

[0035] Step 1: Test the RCS value σ of the UAV with the payload in a microwave darkroom in advance;

[0036] Step 2: The experiment starts, the far-field conditions of the radar antenna are met, and the power of the radar signal is measured;

[0037] Step 2.1: The test distance between the drone and the radar should meet the far-field condition of the radar antenna;

[0038] The far-field conditions of the radar antenna are as follows:

[0039]

[0040] Where R is the test distance; D is the maximum size of the radar antenna aperture; λ is the radar signal wavelength.

[0041] Step 2.2: Obtain the radar power reaching the payload receiving antenna aperture based on the payload measurement.

[0042] According to the radar signal power Pr reaching the payload receiver interface and the payload antenna gain, the radar signal power P reaching the payload is calculated using the formula:

[0043] P=Pr-G

[0044] Where P and Pr are the radar signal powers reaching the payload antenna aperture and the receiver aperture, respectively, in dBm; G is the payload antenna gain, in dBi.

[0045] Step 3: Calculate the UAV echo power based on the UAV RCS data and the radar signal power reaching the payload receiving antenna aperture;

[0046] According to the RCS value σ of the UAV after the payload is mounted measured in the microwave darkroom in advance, and the radar signal power reaching the payload antenna aperture, the target echo power of the UAV can be calculated. The calculation formula is as follows:

[0047]

[0048] Among them, P tar is the UAV target echo power, P is the radar signal power reaching the payload antenna aperture, both in W; σ is the UAV RCS value, in m 2 ; A e is the effective aperture of the antenna, and its expression is:

[0049]

[0050] Where G is the antenna gain, unitless; λ is the wavelength, unit is m.

[0051] Step 4: Adjust the payload simulation echo power to be equal to the drone target echo power. At this time, the target distance simulated by the payload is the experimental distance between the drone and the radar.

[0052] Step 5: Adjust the payload simulation target distance and echo power until the radar just detects the drone target, and then obtain the radar's detection power for the drone.

[0053] The payload simulates the target's movement trajectory away from the radar, and adjusts the payload simulated target distance and echo power. When the simulated target echo power is reduced to the radar receiving sensitivity, that is, the radar just detects the UAV target, then the payload simulated target distance is the radar's detection power to the UAV.

[0054] Take a certain type of ground radar as an example:

[0055] Assuming that the radar operating frequency is 3GHz, the peak transmission power is 200kW, the transmitting antenna size is 6m×6m, the antenna gain is 40dB, the transmitting signal is a linear frequency modulation signal (frequency modulation bandwidth is 2MHz), the detection power for aerial targets with an RCS of 5 square meters is 400km.

[0056] The RCS of the drone after loading is about 0.1m 2 The antenna gain is approximately 0dBi, and the target simulated transmit power range is 40dBm to -50dBm.

[0057] The following describes the outdoor radar power test process as follows:

[0058] a) The drone is lifted to 500 meters, and the distance from the radar meets the far-field condition of the radar antenna, that is,

[0059]

[0060] Where D is the aperture size of the radar antenna; λ is the wavelength of the radar signal.

[0061] Through calculation, the test distance should be greater than 720m. Therefore, the test distance is determined to be 1 km, and the radar antenna elevation angle is about 30°.

[0062] b) When the distance between the UAV and the ground radar is R, the radar signal power (i.e., the pulse amplitude measurement value) reaching our electronic warfare receiver is:

[0063]

[0064] Where P r are the radar signal powers reaching the payload antenna aperture, Pt is the radar transmit peak power, Gt is the radar transmit antenna gain, G is the payload antenna gain, R is the distance between the radar and the payload, λ is the radar signal wavelength, and L is the antenna polarization loss and other losses.

[0065] Through calculation, the radar signal power reaching the payload receiver port is about 18dBm;

[0066] c) The load antenna gain is about 0dBi, so the power reaching the antenna aperture is about 18dBm;

[0067] d) The RCS of the drone with the payload is about 0.1m 2 ;

[0068] e) Based on the radar signal power reaching the payload antenna aperture and the UAV RCS, the target echo power of the UAV can be calculated using the following formula:

[0069]

[0070] Among them, P tar is the UAV target echo power, P is the radar signal power reaching the payload antenna aperture, both in W; σ is the UAV RCS value, in m 2 ; A e is the effective aperture of the antenna, and its expression is:

[0071]

[0072] Where G is the antenna gain, unitless; λ is the wavelength, unit is m.

[0073] After calculation, the radar echo power of the drone is about 39dBm;

[0074] f) The payload simulates the target echo of the UAV, with a starting distance of 1km and a transmission power of 39dBm;

[0075] g) Simulate the target's trajectory away from the radar, and adjust the load simulation echo power according to the simulated target distance. When the simulated echo power is reduced to the radar receiving sensitivity, the radar can just detect the UAV target. The simulated target distance at this time is the radar's detection power for the UAV target;

[0076] The detection power of the radar is 400km (σ=5m 2 ), the RCS of the drone platform is about 0.1m 2 According to the radar equation, it can be calculated that the radar power against the UAV platform is about (400 4 *0.1 / 5) 1 / 4 , that is, 150km; when the simulated target distance is 150km, according to the radar equation, it can be calculated that the echo power should be 39dBm-40*log(150 / 1), that is, -48dBm.

[0077] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A field test method for ground radar power testing, characterized in that: The steps include: Step 1: The RCS of the UAV with the payload is obtained by testing in a microwave darkroom in advance. The payload has the ability to measure radar signals and simulate dynamic target echoes. The payload uses the dynamic target echo simulation capability to simulate the distance, speed, and echo power of the air target echo returning to the radar. The payload simulates the movement trajectory of the UAV platform away from the radar by adjusting the simulated echo amplitude. Step 2: The experiment begins. The far-field conditions of the radar antenna are met and the power of the radar signal is measured. Specifically, it includes: Step 2.1: The test distance between the drone and the radar meets the far-field conditions of the radar antenna as follows: Where R is the test distance; D is the maximum size of the radar antenna aperture; λ is the wavelength of the radar signal; Step 2.2: According to the radar signal power P reaching the payload receiver interface r And the payload antenna gain, calculate the radar signal power P reaching the payload, the calculation formula is: P=P r -G Among them, P, P r are the radar signal powers reaching the payload antenna aperture and the receiver aperture, respectively, in dBm; G is the payload antenna gain, in dBi; Step 3: Calculate the target echo power of the UAV based on the RCS value σ of the UAV after the payload is mounted, which is obtained by microwave darkroom measurement in advance, and the radar signal power reaching the payload antenna aperture. The calculation formula is as follows: Among them, P tar is the UAV target echo power, P is the radar signal power reaching the payload antenna aperture, both in W; σ is the UAV RCS value, in m 2 ; A e is the effective aperture of the antenna, and its expression is: Where G is the antenna gain, unitless; λ is the wavelength, unit is m; Step 4: Adjust the load simulation echo power to be equal to the UAV target echo power. At this time, the target distance simulated by the load is the experimental distance between the UAV and the radar. Step 5: The payload simulates the target's movement trajectory away from the radar. Adjust the payload simulated target distance and echo power. When the simulated target echo power is reduced to the radar receiving sensitivity, the radar just detects the UAV target. At this time, the payload simulated target distance is the radar's detection power to the UAV.

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