A Terahertz Band FOD Radar Beam Field Self-Calibration and Integrated Testing Method

Abstract

This invention discloses a method for on-site self-calibration and integrated testing of terahertz band FOD radar beams. The method includes: constructing a calibration beacon source using the radar's own transmit link and a standard horn antenna, and setting it up in the far field; installing the receive link onto the receive reflector to form a first measurement system, scanning to acquire first amplitude data to obtain the receive radiation pattern and a first turntable angle, calibrating a spatial reference point on the ground using a laser pointer, and recording the reference turntable angle; replacing the receive link with the transmit reflector to form a second measurement system, pointing to the reference turntable angle to acquire second amplitude data to obtain the second turntable angle; adjusting the turntable back to the reference turntable angle, and adjusting the mechanical adjustment mechanism of the transmit reflector until the second amplitude data reaches its maximum value, thus completing beam coincidence calibration. This method requires no external high-end instruments and can achieve radiation pattern testing and high-precision beam alignment on-site using only the radar's own hardware.

Description

Technical Field

[0001] This invention relates to the fields of radar technology and antenna testing technology, and in particular to a method for on-site self-calibration and integrated testing of terahertz band FOD radar beams. Background Technology

[0002] For high-frequency radars employing a physically separate transmit and receive antenna design, ensuring that the main beams of the transmitting and receiving antennas are strictly coincident in the far field is a prerequisite for guaranteeing their optimal detection performance. In applications such as foreign object detection on airport runways, radars need to be deployed outdoors for extended periods, and their beam pointing may drift due to factors such as temperature changes, mechanical vibration, and wind load. Therefore, on-site calibration capabilities are required.

[0003] In the existing technology, the antenna beam testing and calibration methods for this type of radar system mainly fall into the following three categories: The first type is the microwave anechoic chamber testing system. This method places the radar in a microwave anechoic chamber and uses far-field or compact-field testing conditions to obtain the antenna's far-field radiation pattern through a high-precision turntable and a standard measuring antenna. This method is highly accurate, but the microwave anechoic chamber and its supporting testing system are expensive, bulky, and immobile. The radar needs to be disassembled from the field and sent for testing, and the disassembly, transportation, and reinstallation process is time-consuming and costly. Furthermore, the calibration status may be invalidated after reinstallation due to mechanical assembly errors.

[0004] The second method is the field standard signal source comparison method. This method involves setting up a standard transmitter at a far-field location at the radar deployment site, testing the radiation patterns of the transmitting and receiving antennas separately, and determining the beam pointing deviation by comparison. This method is relatively mature below the microwave frequency band, but it faces the problem of standard signal source equipment being extremely expensive, rare, and inconvenient to transport in the terahertz frequency band, making it difficult to implement in actual deployment sites.

[0005] The third category is self-testing methods based on built-in test circuits. Some radar systems integrate built-in test circuits to monitor internal parameters such as transmit power, receiver noise figure, and link gain. However, this type of method can usually only detect link connectivity and basic electrical performance, and cannot measure key system-level performance indicators such as far-field beam shape, pointing angle, and spatial overlap of transmit and receive beams.

[0006] Furthermore, existing technologies lack an integrated method for simultaneously performing antenna pattern testing and beam coincidence calibration on-site using the hardware of a terahertz radar with physically separated dual reflector antennas. The lack of available high-frequency standard testing equipment at radar deployment sites makes it difficult to independently and efficiently complete system performance verification and beam calibration.

[0007] In summary, existing technologies for field performance verification and beam calibration of FOD radars with physically separated dual reflector antennas in the terahertz band suffer from several drawbacks, including strong dependence on external high-end testing equipment, inability to complete the process independently on-site, and limited functionality that fails to meet beam overlap calibration requirements. Summary of the Invention

[0008] To address the technical problems existing in the background art, this invention proposes a method for on-site self-calibration and integrated testing of terahertz band FOD radar beams.

[0009] This invention proposes a field self-calibration and integrated testing method for a terahertz band FOD radar beam. The radar includes a base, a turntable system mounted on the base, and physically separated transmitting and receiving modules. The transmitting module includes a transmitting reflector and a transmitting link, and the receiving module includes a receiving reflector and a receiving link. The method includes the following steps: S1. Combine the radar's own transmission link with a standard horn antenna to construct a calibration beacon source, and set up the calibration beacon source at the far field distance of the radar body. S2. The receiving link is physically installed at the feed position of the receiving reflector to form the first measurement system. The turntable system is controlled to drive the radar antenna to scan and obtain the first amplitude data of the calibration beacon source transmitted signal received by the first measurement system. The first amplitude data is processed to obtain the radiation pattern of the receiving reflector and the first turntable angle corresponding to the point of maximum signal amplitude. A spatial reference point is marked on the ground in front of the radar by a laser pointer fixed on the receiving reflector or its support, and the turntable angle at this time is recorded as the reference turntable angle. S3. The receiving link is detached from the receiving reflector and physically installed at the feed position of the transmitting reflector to form a second measurement system. The turntable system is controlled to drive the radar antenna to point to the reference turntable angle. The second amplitude data of the calibration beacon source transmitted signal received by the second measurement system is obtained. The second amplitude data is processed to obtain the second turntable angle corresponding to the point of maximum signal amplitude. S4. Adjust the turntable angle back to the reference turntable angle, change the direction of the transmitted beam by adjusting the mechanical adjustment mechanism attached to the transmitting reflector or its feed source, and acquire the second amplitude data received by the second measurement system in real time until the second amplitude data reaches the maximum value and stop adjusting to complete the beam overlap calibration.

[0010] Preferably, in step S1, the far-field distance According to the formula It is confirmed that, among them, This is the maximum size of the reflecting surface. This refers to the operating wavelength of the radar.

[0011] Preferably, the step of acquiring the first amplitude data of the calibration beacon source transmitted signal received by the first measurement system, and processing the first amplitude data to obtain the receiving reflector pattern and the first turntable angle corresponding to the point of maximum signal amplitude, specifically includes: The control turntable system scans point by point in the azimuth and pitch directions, records the first amplitude data corresponding to each scanning angle point, and plots a curve of signal amplitude changing with angle based on the recorded multiple angle points and their corresponding first amplitude data. The curve is used as the radiation pattern of the receiving reflector, and the angle corresponding to the maximum signal amplitude point on the curve is determined as the first turntable angle.

[0012] Preferably, the control turntable system drives the radar antenna to point at the reference turntable angle, acquires the second amplitude data of the calibration beacon source transmitted signal received by the second measurement system, and processes the second amplitude data to obtain the second turntable angle corresponding to the point of maximum signal amplitude, specifically including: The control turntable system drives the radar antenna to point to the reference turntable angle. Centered on the reference turntable angle, it performs point-by-point scanning in the azimuth and elevation directions within a preset angle range with a preset step angle. It records the second amplitude data corresponding to each scanning angle point, compares all the recorded second amplitude data, and takes the scanning angle point corresponding to the maximum value as the second turntable angle.

[0013] Preferably, the first amplitude data and the second amplitude data are electrical parameters reflecting signal strength, specifically including at least one of voltage value, power value or field strength value; the optical axis of the laser pointer is pre-calibrated to be parallel to the electrical axis of the receiving reflective surface, and the beam direction of the laser pointer is vertically downward.

[0014] Preferably, in step S2, the spatial reference point is a permanent mark at the center of the laser spot formed by the laser pointer on the ground.

[0015] Preferably, in step S3, the spatial pointing deviation direction of the transmitted beam and the received beam is determined by observing the positional deviation between the light spot generated by the laser pointer and the spatial reference point.

[0016] This invention proposes a terahertz band FOD radar beam field self-calibration system for implementing the method described in any of the above-mentioned embodiments, comprising: The calibration beacon source, consisting of the radar's own transmission link and a standard horn antenna, is used to generate calibration signals. The calibration beacon source is set up in the far field of the radar body, forming a calibration signal transmission link with the radar body. The first measurement system consists of a receiving link physically installed at the feed position of the receiving reflector. It is used to receive the signal transmitted by the calibration beacon source under the drive of the turntable system and output the first amplitude data. The first amplitude data is used to generate the radiation pattern of the receiving reflector and determine the first turntable angle corresponding to the point of maximum signal amplitude. The laser calibration module includes a laser pointer fixed to the receiving reflective surface or its bracket. The laser pointer's beam direction is vertically downward, used to form a light spot on the ground in front of the radar to calibrate a spatial reference point. When calibrating the spatial reference point, the angle of the turntable system is recorded as the reference turntable angle. The second measurement system consists of a receiving link that is detached from the receiving reflector and physically installed at the feed position of the transmitting reflector. It is used to receive the signal transmitted by the calibration beacon source when the turntable system is driven to point to the reference turntable angle and output the second amplitude data. The second amplitude data is used to determine the second turntable angle corresponding to the point of maximum signal amplitude. A mechanical adjustment module, attached to the emitting reflector or its feed source, is mechanically connected to the emitting reflector. It is used to adjust the spatial pointing angle of the emitting reflector according to the real-time acquired second amplitude data when the turntable angle is maintained at the reference turntable angle, until the second amplitude data reaches its maximum value.

[0017] Preferably, the optical axis of the laser pointer is pre-calibrated to be parallel to the electrical axis of the receiving reflective surface, and the spatial reference point is a permanent mark at the center of the laser spot.

[0018] Preferably, the turntable system is used to drive the radar antenna to perform point-by-point scanning in the azimuth and elevation directions, and output the real-time angle data of the radar antenna to the first measurement system or the second measurement system.

[0019] The proposed terahertz band FOD radar beam self-calibration and integrated testing method eliminates the reliance on expensive external terahertz testing instruments and fixed anechoic chamber facilities. It can independently complete antenna pattern testing and transmit / receive beam coincidence calibration on-site using only the radar's own hardware and simple auxiliary tools. By organically combining "physical replacement of the receiver link" and "laser spatial calibration", pattern diagnosis and beam coincidence calibration are completed sequentially under the same far-field beacon source setting, realizing integrated and efficient on-site operation. The laser downward ground calibration transforms the invisible RF beam direction into a stable and visible ground optical reference. The principle is intuitive, the operation is simple, and it is not affected by far-field screen shaking. Combined with a precision mechanical adjustment mechanism, it ensures traceable calibration accuracy and reliable and repeatable results. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the workflow of a terahertz band FOD radar beam field self-calibration and integrated testing method proposed in this invention. Figure 2 This is a schematic diagram of one embodiment of the on-site self-calibration and integrated testing method for terahertz band FOD radar beam proposed in this invention. Figure 3This is a schematic diagram of the beam spatial pointing before calibration, representing one embodiment of the on-site self-calibration and integrated testing method for terahertz band FOD radar beams proposed in this invention. Figure 4 This is a schematic diagram of the spatial pointing of the calibrated beam, representing one embodiment of the on-site self-calibration and integrated testing method for terahertz band FOD radar beams proposed in this invention. Figure 5 This is the azimuth pattern of the receiving antenna at a distance of 130m, as shown in Embodiment 1 of the on-site self-calibration and integrated testing method for terahertz band FOD radar beam proposed in this invention. Figure 6 This is the azimuth pattern of the transmitting antenna at a distance of 130m, which is an embodiment of the on-site self-calibration and integrated testing method for terahertz band FOD radar beam proposed in this invention. Detailed Implementation

[0021] Reference Figures 1-6 This invention proposes a method for on-site self-calibration and integrated testing of a terahertz band FOD radar beam. The radar includes a base, a turntable system mounted on the base, and physically separated transmitting and receiving modules. The transmitting module includes a transmitting reflector and a transmitting link, and the receiving module includes a receiving reflector and a receiving link. The method includes the following steps: S1. Combine the radar's own transmission link with a standard horn antenna to construct a calibration beacon source, and set up the calibration beacon source at the far field distance of the radar body.

[0022] In this embodiment, in step S1, the far-field distance According to the formula It is confirmed that, among them, This is the maximum size of the reflecting surface. This refers to the operating wavelength of the radar.

[0023] S2. The receiving link is physically installed at the feed position of the receiving reflector to form the first measurement system. The turntable system is controlled to drive the radar antenna to scan and obtain the first amplitude data of the calibration beacon source transmitted signal received by the first measurement system. The first amplitude data is processed to obtain the radiation pattern of the receiving reflector and the first turntable angle corresponding to the point of maximum signal amplitude. A spatial reference point is marked on the ground in front of the radar by a laser pointer fixed on the receiving reflector or its support, and the turntable angle at this time is recorded as the reference turntable angle.

[0024] In this embodiment, the first amplitude data of the calibration beacon source transmitted signal received by the first measurement system is acquired, and the first amplitude data is processed to obtain the receiving reflector pattern and the first turntable angle corresponding to the point of maximum signal amplitude. Specifically, this includes: The control turntable system scans point by point in the azimuth and pitch directions, records the first amplitude data corresponding to each scanning angle point, and plots a curve of signal amplitude changing with angle based on the recorded multiple angle points and their corresponding first amplitude data. The curve is used as the radiation pattern of the receiving reflector, and the angle corresponding to the maximum signal amplitude point on the curve is determined as the first turntable angle.

[0025] In this embodiment, in step S2, the spatial reference point is a permanent mark at the center of the laser spot formed by the laser pointer on the ground.

[0026] S3. The receiving link is detached from the receiving reflector and physically installed at the feed position of the transmitting reflector to form a second measurement system. The control turntable system drives the radar antenna to point to the reference turntable angle, and the second amplitude data of the calibration beacon source transmitted signal received by the second measurement system is obtained. The second amplitude data is processed to obtain the second turntable angle corresponding to the point of maximum signal amplitude.

[0027] In this embodiment, the control turntable system drives the radar antenna to point at the reference turntable angle, acquires the second amplitude data of the calibration beacon source transmitted signal received by the second measurement system, and processes the second amplitude data to obtain the second turntable angle corresponding to the point of maximum signal amplitude. Specifically, this includes: The control turntable system drives the radar antenna to point to the reference turntable angle. Centered on the reference turntable angle, it performs point-by-point scanning in the azimuth and elevation directions within a preset angle range with a preset step angle. It records the second amplitude data corresponding to each scanning angle point, compares all the recorded second amplitude data, and takes the scanning angle point corresponding to the maximum value as the second turntable angle.

[0028] In this embodiment, the first amplitude data and the second amplitude data are electrical parameters reflecting the signal strength, specifically including at least one of voltage value, power value, or field strength value.

[0029] Specifically, the optical axis of the laser pointer is pre-calibrated to be parallel to the electrical axis of the receiving reflective surface, and the beam direction of the laser pointer is vertically downward.

[0030] In this embodiment, step S3 further includes determining the spatial pointing deviation direction between the transmitted beam and the received beam by observing the positional deviation between the light spot generated by the laser pointer and the spatial reference point.

[0031] S4. Adjust the turntable angle back to the reference turntable angle, change the direction of the transmitted beam by adjusting the mechanical adjustment mechanism attached to the transmitting reflector or its feed source, and acquire the second amplitude data received by the second measurement system in real time until the second amplitude data reaches the maximum value and stop adjusting to complete the beam overlap calibration.

[0032] Example 1:

[0033] This embodiment uses a 240GHz airport runway foreign object detection radar, comprising a base, a turntable system mounted on the base, a fixed base plate, and physically separated transmitting and receiving modules. The transmitting module includes a transmitting reflector, a transmitting link, and a transmitting horn antenna, and is mounted on a transmitting fixed L-shaped bracket, with a transmitting module fixing and adjustment mechanism attached. The receiving module includes a receiving reflector, a receiving link, and a receiving horn antenna, and is mounted on a receiving fixed L-shaped bracket, with a receiving module fixing mechanism attached.

[0034] First, complete the initial high-precision mechanical assembly of the radar to ensure that the relative optical positions of each reflector and its own feed source are correct and secure.

[0035] The radar's own transmission link is combined with a standard gain horn antenna. In this embodiment, a WR-3.4 standard gain horn with a gain of 25dBi is used to construct a 240GHz calibration beacon source with stable frequency and known power. The entire beacon source is mounted on a height-adjustable (up to 3 meters) universal fixture bracket. The bracket base is stable, allowing for flexible adjustment of the beacon source's installation height and horizontal position on site.

[0036] The installation distance is determined based on the antenna far-field condition formula. In this embodiment, the reflector is rectangular, with a length L = 150cm and a width W = 15cm, and its maximum dimension D = 1.5m. The operating frequency of 240GHz corresponds to a wavelength... Calculate the minimum far-field distance. At the actual airport runway site, considering site limitations and engineering precision requirements, a location of 300 meters was selected to securely and accurately install the beacon source. Figure 2 As shown. Although this distance does not strictly meet the 3600m far-field condition, with subsequent mechanical fine-tuning, an engineering-acceptable beam coincidence accuracy can still be achieved. The line connecting the beacon source and the radar base forms the calibration reference axis.

[0037] The receiving link and its connected receiving horn antenna are physically installed as a single unit at the feed position of the receiving reflector. At this point, the system consists of the lower reflector and the receiving link, forming the first measurement system.

[0038] Turn on the far-field calibration beacon source. Control the turntable system to drive the radar antenna to perform point-by-point scanning in the azimuth and elevation directions, with a scanning range of ±5° in the azimuth and ±5° in the elevation directions, and a step angle of 0.1°. Use an oscilloscope (or spectrum analyzer) to monitor the amplitude of the center frequency signal after downconversion in the receiving link, and record the voltage value corresponding to each scanning angle point as the first amplitude data. Plot the recorded multiple angle points and their corresponding voltage values ​​as a curve of signal amplitude changing with angle; this curve is the measured radiation pattern of the lower reflector antenna. Determine the angle corresponding to the point with the maximum signal amplitude on the curve and record it as the first turntable angle (Az_Rmax, El_Rmax).

[0039] The control turntable system is precisely aligned with the radar antenna at (Az_Rmax, El_Rmax) to maximize the signal reception on the lower reflector. At this point, the laser designator, precisely mounted on the lower reflector support with its beam pointing vertically downwards, is activated. This embodiment uses a 635nm red laser module with a power of <5mW. The optical axis of this laser designator has been pre-calibrated parallel to the electrical axis of the receiving reflector (calibration method: performed in a dark room using a collimator). The laser forms a clear spot on the ground in front of the radar. A fine, permanent mark is made at the center of this spot, designated as point P, which serves as the spatial reference point. Simultaneously, the angle of the turntable system at this moment (Az_Rref, El_Rref) is firmly recorded as the reference turntable angle.

[0040] Keeping the turntable system and other components stationary, detach the receiving link and receiving horn antenna from the lower reflector and physically install them at the feed position on the upper reflector (i.e., the transmitting reflector). At this point, the system is reconfigured into a second measurement system consisting of the upper reflector and the receiving link.

[0041] The control turntable system drives the radar antenna to point at a reference turntable angle (Az_Rref, El_Rref). Due to potential deviations between the transmitted and received beams, a point-by-point scan is performed within a preset angle range of ±1° in azimuth and ±1° in elevation, centered on the reference turntable angle and in 0.1° increments. The second amplitude data corresponding to each scan angle point is recorded; in this embodiment, the voltage value is also recorded. All recorded second amplitude data are compared, and the scan angle point corresponding to the maximum value is taken as the second turntable angle (Az_Tmax, El_Tmax).

[0042] During this process, the operator can observe the positional deviation between the laser spot generated by the laser pointer and the ground marker point P. The laser spot is generated by the upper reflector or the still-on lower reflector laser pointer. This deviation visually reflects the spatial pointing difference between the upper and lower beams. For example, if the laser spot appears to the left of point P, it indicates that the emitted beam is pointing to the left. This deviation direction will serve as a reference for subsequent mechanical fine-tuning.

[0043] Adjust the turntable system angle precisely back to the reference turntable angle (Az_Rref, El_Rref). At this point, the laser spot on the lower reflector should be re-aligned with the ground marker point P, indicating that the receiving beam has been locked onto the beacon source.

[0044] While ensuring the turntable, reflector, and internal optical structure of the feed source remain absolutely unchanged, mechanical fine-tuning is performed using the fixed adjustment mechanism of the emission module attached to the emission reflector. In this embodiment, a precision fine-tuning device with differential threads is used, with an adjustment resolution of 0.01° and a range of ±2°. Simultaneously with fine-tuning, the output signal amplitude of the second measurement system (i.e., the second amplitude data) is monitored in real time. When the signal amplitude is adjusted to its maximum value, adjustment is immediately stopped and all adjustment mechanisms are locked.

[0045] The calibration is now complete. Figure 3 and Figure 4 As shown, at this point, the receiving beam remains aligned with the beacon source through a fixed turntable angle (Az_Rref, El_Rref); the transmitting beam, through its own mechanical fine-tuning, also aligns its maximum radiation direction with the same beacon source. Therefore, the radar's transmitting and receiving beams achieve mainlobe overlap at the far-field beacon source location.

[0046] After completing the beam coincidence calibration, keep the turntable angle as the reference turntable angle (Az_Rref, El_Rref) and acquire the amplitude data of the calibration beacon source transmitted signal received by the second measurement system again. Compare this amplitude value with the maximum value recorded during the calibration process. If the difference between the two is less than a preset threshold (in this embodiment, the preset threshold is set to 0.2dB), the beam coincidence calibration is confirmed to be effective. If the deviation exceeds the preset threshold, step S4 can be repeated for fine-tuning until the requirements are met.

[0047] Furthermore, the single-receiver link physical replacement measurement method proposed in this application also possesses comprehensive testing capabilities for antenna pattern diagnosis and gain calibration. Before performing on-site self-calibration using the method of this application, far-field pattern tests were first conducted on both the receiving reflector and the transmitting reflector using the same set of receiver link physical replacement methods. Figure 5 As shown, the azimuth pattern of the receiving antenna measured at a distance of 130m has a clear main lobe and good symmetry; Figure 6 As shown, the azimuth radiation pattern of the transmitting antenna measured at the same distance also exhibits a typical beam shape. The aforementioned radiation pattern data demonstrates that the far-field directional characteristics of a dual-reflector antenna can be effectively obtained using only the calibration beacon source constructed from the radar's own transmission link, verifying the feasibility of the proposed method for antenna performance diagnosis without relying on external high-end instruments.

[0048] Furthermore, based on the radiation pattern test results, the absolute gain of the transmitting and receiving antennas was calculated using the standard gain horn comparison method. In the test, the radar's own transmit link was combined with a standard horn antenna with a gain of 25 dBi as a beacon source. The received power at a distance of 21 m was measured to be -23.45 dBm. Using the free-space propagation loss formula, the theoretical received power at a distance of 240 m was calculated to be -44.61 dBm. Combining the measured maximum power data of the transmitting and receiving links (transmit link -14.45 dBm, receive link -15.36 dBm), the transmit antenna gain was calculated to be approximately 55.16 dBi, and the receive antenna gain was approximately 54.25 dBi. This gain value matches the design specifications, further verifying the accuracy and reliability of the proposed method for quantitative performance evaluation in the terahertz band.

[0049] In summary, through on-site radiation pattern testing and gain calculation, it has been demonstrated that the method proposed in this application can not only complete beam overlap calibration, but also simultaneously achieve antenna radiation pattern diagnosis and gain calibration without adding any external dedicated testing equipment. This fully demonstrates the practical value and technical advantages of this application as an integrated on-site testing method for terahertz FOD radar.

[0050] Reference Figures 1-4 The present invention proposes a terahertz band FOD radar beam field self-calibration system for implementing any of the above methods, comprising: The calibration beacon source, consisting of the radar's own transmission link and a standard horn antenna, is used to generate calibration signals. The calibration beacon source is set up in the far field of the radar body, forming a calibration signal transmission link with the radar body. The first measurement system consists of a receiving link physically installed at the feed position of the receiving reflector. It is used to receive the signal transmitted by the calibration beacon source under the drive of the turntable system and output the first amplitude data. The first amplitude data is used to generate the radiation pattern of the receiving reflector and determine the first turntable angle corresponding to the point of maximum signal amplitude. The laser calibration module includes a laser pointer fixed to the receiving reflective surface or its bracket. The laser pointer's beam direction is vertically downward, used to form a light spot on the ground in front of the radar to calibrate a spatial reference point. When calibrating the spatial reference point, the angle of the turntable system is recorded as the reference turntable angle. The second measurement system consists of a receiving link that is detached from the receiving reflector and physically installed at the feed position of the transmitting reflector. It is used to receive the signal transmitted by the calibration beacon source when the turntable system is driven to point to the reference turntable angle and output the second amplitude data. The second amplitude data is used to determine the second turntable angle corresponding to the point of maximum signal amplitude. A mechanical adjustment module, attached to the emitting reflector or its feed source, is mechanically connected to the emitting reflector. It is used to adjust the spatial pointing angle of the emitting reflector according to the real-time acquired second amplitude data when the turntable angle is maintained at the reference turntable angle, until the second amplitude data reaches its maximum value.

[0051] In this embodiment, the optical axis of the laser pointer is pre-calibrated to be parallel to the electrical axis of the receiving reflective surface, and the spatial reference point is a permanent mark at the center of the light spot.

[0052] In this embodiment, the turntable system is used to drive the radar antenna to perform point-by-point scanning in the azimuth and elevation directions, and output the real-time angle data of the radar antenna to the first measurement system or the second measurement system.

[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for on-site self-calibration and integrated testing of a terahertz band FOD radar beam, wherein the radar includes a base, a turntable system mounted on the base, and physically separated transmitting and receiving modules, the transmitting module comprising a transmitting reflector and a transmitting link, and the receiving module comprising a receiving reflector and a receiving link; characterized in that, Includes the following steps: S1. Combine the radar's own transmission link with a standard horn antenna to construct a calibration beacon source, and set up the calibration beacon source at the far field distance of the radar body. S2. The receiving link is physically installed at the feed position of the receiving reflector to form the first measurement system. The turntable system is controlled to drive the radar antenna to scan and obtain the first amplitude data of the calibration beacon source transmitted signal received by the first measurement system. The first amplitude data is processed to obtain the radiation pattern of the receiving reflector and the first turntable angle corresponding to the point of maximum signal amplitude. A spatial reference point is marked on the ground in front of the radar by a laser pointer fixed on the receiving reflector or its support, and the turntable angle at this time is recorded as the reference turntable angle. S3. The receiving link is detached from the receiving reflector and physically installed at the feed position of the transmitting reflector to form a second measurement system. The turntable system is controlled to drive the radar antenna to point to the reference turntable angle. The second amplitude data of the calibration beacon source transmitted signal received by the second measurement system is obtained. The second amplitude data is processed to obtain the second turntable angle corresponding to the point of maximum signal amplitude. S4. Adjust the turntable angle back to the reference turntable angle, change the direction of the transmitted beam by adjusting the mechanical adjustment mechanism attached to the transmitting reflector or its feed source, and acquire the second amplitude data received by the second measurement system in real time until the second amplitude data reaches the maximum value and stop adjusting to complete the beam overlap calibration.

2. The terahertz band FOD radar beam field self-calibration and integrated testing method according to claim 1, characterized in that, In step S1, far-field distance According to the formula It is confirmed that, among them, This is the maximum size of the reflecting surface. This refers to the operating wavelength of the radar.

3. The terahertz band FOD radar beam field self-calibration and integrated testing method according to claim 1, characterized in that, The process of acquiring the first amplitude data of the calibration beacon source transmitted signal received by the first measurement system, and processing the first amplitude data to obtain the receiving reflector radiation pattern and the first turntable angle corresponding to the point of maximum signal amplitude, specifically includes: The control turntable system scans point by point in the azimuth and pitch directions, records the first amplitude data corresponding to each scanning angle point, and plots a curve of signal amplitude changing with angle based on the recorded multiple angle points and their corresponding first amplitude data. The curve is used as the radiation pattern of the receiving reflector, and the angle corresponding to the maximum signal amplitude point on the curve is determined as the first turntable angle.

4. The terahertz band FOD radar beam field self-calibration and integrated testing method according to claim 1, characterized in that, The control turntable system drives the radar antenna to point at the reference turntable angle, acquires the second amplitude data of the calibration beacon source transmitted signal received by the second measurement system, and processes the second amplitude data to obtain the second turntable angle corresponding to the point of maximum signal amplitude. Specifically, this includes: The control turntable system drives the radar antenna to point to the reference turntable angle. Centered on the reference turntable angle, it performs point-by-point scanning in the azimuth and elevation directions within a preset angle range with a preset step angle. It records the second amplitude data corresponding to each scanning angle point, compares all the recorded second amplitude data, and takes the scanning angle point corresponding to the maximum value as the second turntable angle.

5. The terahertz band FOD radar beam field self-calibration and integrated testing method according to claim 1, characterized in that, The first amplitude data and the second amplitude data are electrical parameters reflecting signal strength, specifically including at least one of voltage value, power value or field strength value; the optical axis of the laser pointer is pre-calibrated to be parallel to the electrical axis of the receiving reflective surface, and the beam direction of the laser pointer is vertically downward.

6. The terahertz band FOD radar beam field self-calibration and integrated testing method according to claim 1, characterized in that, In step S2, the spatial reference point is a permanent mark at the center of the laser spot formed on the ground by the laser pointer.

7. The terahertz band FOD radar beam field self-calibration and integrated testing method according to claim 1, characterized in that, Step S3 also includes determining the spatial pointing deviation direction of the transmitted beam and the received beam by observing the positional deviation between the light spot generated by the laser pointer and the spatial reference point.

8. A terahertz band FOD radar beam field self-calibration system, used to implement the method according to any one of claims 1 to 7, characterized in that, include: The calibration beacon source, consisting of the radar's own transmission link and a standard horn antenna, is used to generate calibration signals. The calibration beacon source is set up in the far field of the radar body, forming a calibration signal transmission link with the radar body. The first measurement system consists of a receiving link physically installed at the feed position of the receiving reflector. It is used to receive the signal transmitted by the calibration beacon source under the drive of the turntable system and output the first amplitude data. The first amplitude data is used to generate the radiation pattern of the receiving reflector and determine the first turntable angle corresponding to the point of maximum signal amplitude. The laser calibration module includes a laser pointer fixed to the receiving reflective surface or its bracket. The laser pointer's beam direction is vertically downward, used to form a light spot on the ground in front of the radar to calibrate a spatial reference point. When calibrating the spatial reference point, the angle of the turntable system is recorded as the reference turntable angle. The second measurement system consists of a receiving link that is detached from the receiving reflector and physically installed at the feed position of the transmitting reflector. It is used to receive the signal transmitted by the calibration beacon source when the turntable system is driven to point to the reference turntable angle and output the second amplitude data. The second amplitude data is used to determine the second turntable angle corresponding to the point of maximum signal amplitude. A mechanical adjustment module, attached to the emitting reflector or its feed source, is mechanically connected to the emitting reflector. It is used to adjust the spatial pointing angle of the emitting reflector according to the real-time acquired second amplitude data when the turntable angle is maintained at the reference turntable angle, until the second amplitude data reaches its maximum value.

9. The terahertz band FOD radar beam field self-calibration system according to claim 8, characterized in that, The optical axis of the laser pointer is pre-calibrated to be parallel to the electrical axis of the receiving reflective surface, and the spatial reference point is a permanent mark at the center of the laser spot.

10. The terahertz band FOD radar beam field self-calibration system according to claim 8, characterized in that, The turntable system is used to drive the radar antenna to perform point-by-point scanning in the azimuth and elevation directions, and output the real-time angle data of the radar antenna to the first measurement system or the second measurement system.

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