System and method for verifying target scattering characteristics for a flight test

Abstract

A system and method for verifying the scattering characteristics of an airborne escort target, a two-aircraft formation is constructed for scattering characteristic testing, a forward pod is installed at the wing tip of the leading edge of each aircraft, a rearward pod is installed at the wing tip of the trailing edge, and a complete radar transmitter and receiver are integrated inside each pod, which can independently complete radar signal transmission, scattering signal reception and preliminary processing. The aircraft is equipped with a global positioning system and a tactical data link for precise positioning of the aircraft and sharing and collaboration of key information. The invention uses multiple flight strategies such as forward and rear formation, lateral formation and dynamic formation to measure the mutual irradiation of the two aircrafts, comprehensively obtain the forward, rear, lateral and full-angle radar scattering characteristic signals of the target aircraft, generate high-precision two-dimensional radar images by combining echo data processing technology, and accurately locate electromagnetic scattering defects.

Description

Technical Field

[0001] This invention relates to the field of radar target scattering characteristic measurement technology. Specifically, it relates to a system and method for accurately verifying radar target scattering characteristics of stealth aircraft in actual flight conditions through a dual-aircraft aerial escort method. This system can be widely applied to scenarios such as stealth performance testing, periodic diagnosis, and optimization design of stealth aircraft. Background Technology

[0002] Radar target scattering characteristics are a core indicator for evaluating the stealth performance of an aircraft, and the accuracy of its testing and verification directly affects the aircraft's combat effectiveness and survivability. Currently, the industry mainly relies on two types of technical solutions for testing and verifying the radar target scattering characteristics of stealth aircraft: one is static field testing, including far-field measurement and near-field measurement. Static far-field measurement requires the construction of an open test site, using plane waves to illuminate a stationary stealth target to obtain scattering data. However, this solution is limited by the site area, has high testing costs, and cannot simulate the dynamic characteristics of the aircraft during actual flight, such as engine operating conditions, component vibrations, and wing elevation angles. Static near-field measurement can shorten the test distance by utilizing the multipath effect, but it also has the drawback of not being able to reflect dynamic flight conditions, and the test results are easily affected by the site environment. Another type is dynamic testing. Existing technologies mostly rely on ground radar stations to measure targets in flight. However, this approach has significant limitations: First, flight path planning is complex and limited by the deployment location and detection angle of the ground radar. It can usually only obtain limited elevation angle data and it is difficult to achieve depression angle measurement, thus failing to cover the testing requirements for full-angle scattering characteristics. Second, the test results are singular, only obtaining the radar cross section (RCS) curve and failing to generate intuitive radar scattering images, making it difficult to locate scattering defects. Third, the measurement accuracy is limited. The distance between the ground radar and the flying target is relatively long, resulting in significant signal attenuation and susceptibility to atmospheric turbulence, electromagnetic interference, and other factors, making it difficult to meet the requirements for high-precision testing.

[0003] Meanwhile, the stealth performance of stealth aircraft relies on the synergistic effect of the radar-absorbing structure shape and the radar-absorbing coating. In complex and variable service environments, aircraft are susceptible to external factors such as temperature changes, airflow impact, vibration, and chemical corrosion, leading to problems such as coating peeling and structural deformation, which in turn degrade stealth performance. Therefore, regular diagnosis and testing of the radar scattering characteristics of stealth aircraft, and timely detection and repair of scattering defects, are crucial to maintaining the integrity of their stealth performance. However, existing testing technologies cannot achieve comprehensive and accurate measurements under actual flight conditions, making it difficult to meet the diagnostic needs of practical applications.

[0004] Therefore, how to accurately measure the scattering characteristics of aircraft targets under actual flight conditions has become a technical problem that needs to be solved by existing technologies. Summary of the Invention

[0005] The core objective of this invention is to overcome the technical deficiencies of existing static testing and ground dynamic testing, and to provide a system and method for verifying the scattering characteristics of a target during aerial escort. This system enables comprehensive measurement of the radar scattering characteristics of stealth aircraft in flight, including forward, backward, and lateral angles (all directions and all pitch angles). It acquires scattering data and high-precision two-dimensional radar images under real flight conditions, accurately locates electromagnetic scattering defects, and provides a scientific and reliable technical basis for the stealth performance evaluation, periodic diagnosis, and optimized design of stealth aircraft.

[0006] To achieve this objective, the present invention adopts the following technical solution: A system for aerial escort verification of target scattering characteristics, comprising at least two aircraft for formation flight, characterized in that: Each of the aforementioned aircraft is equipped with a forward pod at the leading edge wingtip and a rearward pod at the trailing edge wingtip, and both the forward and rearward pods integrate a complete radar transmitter and receiver. The radar transmitter is used to transmit radar wave detection signals; The receiver is used to capture radar-scattered echo signals; The aircraft also includes a global positioning system and a tactical data link; The global positioning system is used to accurately locate the two aircraft. The tactical data link is used to enable real-time sharing and coordinated synchronization of position, speed and time information between the two aircraft, ensuring consistency of measurement timing.

[0007] Optionally, the global positioning system includes at least one of GPS, BeiDou, and Galileo.

[0008] Optionally, the tactical data link includes at least one of Link-16 and TTNT, and has anti-interference and high-bandwidth data transmission capabilities.

[0009] Optionally, both the forward and rearward pods are standardized detachable structures that connect to the aircraft wings via a universal mounting interface. They can be replaced with radar pods of different frequency bands according to testing requirements, and are compatible with a variety of commonly used radar frequency bands such as L, S, C, X, and Ku.

[0010] Optionally, the forward and rearward pods also have pitch and yaw angle adjustment functions.

[0011] This invention further discloses a method for verifying the scattering characteristics of a target during aerial escort based on the above system, characterized in that it includes: By changing the order and flight attitude of the aircraft in the multi-mode formation flight, and using forward and / or backward pods to perform measurements, the forward and backward scattering characteristics, side scattering characteristics, and two-dimensional radar image acquisition verifications are completed.

[0012] Optionally, the forward and backward scattering characteristics are verified as follows: The first step is to plan the flight path, control the two aircraft to start and fly in formation, so that the first aircraft is at a predetermined distance in front of the second aircraft, and maintain the stability of the formation; The second step involves starting the first aircraft and then transmitting radar wave detection signals to the second aircraft via the radar transmitter and receiver inside the pod. At the same time, the receiver captures and records the forward radar scattering characteristic signal of the second aircraft. The third step is to simultaneously activate the radar transmitter and receiver in the forward pod of the second aircraft to transmit radar wave detection signals to the first aircraft, and capture and record the rearward radar scattering characteristic signals of the first aircraft. The fourth step is to transmit the scattering characteristic signals acquired by the two aircraft to the data processing center through the tactical data link. After processing the signals, the radar scattering characteristic curves of the target are obtained, and the electromagnetic scattering defects of the two aircraft are initially located. The fifth step is to adjust the flight attitude and flight path of the two aircraft so that the second aircraft moves to a preset distance in front of the first aircraft and re-stabilizes the formation. The sixth step involves using the forward pod of the first aircraft to conduct radar detection, measuring and processing the backward radar scattering characteristic signal of the second aircraft, and then using the backward pod of the second aircraft to conduct radar detection, measuring and processing the forward radar scattering characteristic signal of the first aircraft. The seventh step is to detect and locate the electromagnetic scattering defects of the first and second aircraft based on the radar scattering characteristic signals returned by the two aircraft.

[0013] Optionally, the lateral scattering characteristics are verified as follows: First, control the two aircraft to adjust their formation attitude and maintain lateral parallel flight, so that the second aircraft is located at a predetermined lateral distance to the side of the first aircraft, ensuring that the lateral scattering signal is unobstructed and within the effective range of radar detection; Subsequently, the radar transmitter and receiver in the forward pod of the second aircraft were activated to continuously transmit detection signals to the first aircraft, capturing and recording its lateral radar scattering characteristic signals; Finally, the positions of the two aircraft were adjusted so that the first aircraft was located to the side of the second aircraft. The above measurement operations were repeated to complete the comprehensive acquisition of the lateral scattering data of the two aircraft and to achieve complete verification of the lateral scattering characteristics.

[0014] Optionally, the two-dimensional radar image acquisition verification is as follows: First, control the two aircraft to fly in formation, so that the second aircraft is initially located at a preset position to the right rear of the first aircraft, ensuring that the radar signal can effectively illuminate the target without obstruction; Subsequently, the second aircraft smoothly passed behind the first aircraft along a pre-set, smooth trajectory, eventually reaching a pre-set position on the left rear, maintaining relative formation stability throughout the process. During flight, the radar transmitter and receiver in the forward-facing pod of the second aircraft were continuously activated to maintain continuous illumination of the first aircraft, simultaneously acquiring continuous echo data under different positional relationships. Using the echo data, a high-resolution two-dimensional radar image of the first aircraft was generated. Finally, the positions of the two aircraft were adjusted so that the first aircraft moved to the side and rear of the second aircraft. The above operation was repeated to obtain a two-dimensional radar image of the second aircraft.

[0015] Optionally, by analyzing two-dimensional radar images and combining them with radar scattering characteristic signals, the magnitude and physical location of electromagnetic scattering defects on the surface of the aircraft can be accurately determined.

[0016] In summary, the present invention has the following advantages: 1. Comprehensive and accurate measurement: This invention, through a dual-aircraft escort design, breaks through the angle limitations of ground radar testing, achieving comprehensive measurement of radar scattering characteristics across all angles (all directions and all pitch angles) in the forward, backward, and lateral directions. The measurement process reflects the actual flight state of a real aircraft, reflecting the impact of dynamic factors such as engine operation, component vibration, and wing pitch angle on scattering characteristics, and the acquired data is more consistent with actual application scenarios. Combined with high-resolution two-dimensional radar images, it achieves precise location of scattering defects, solving the problem that traditional testing can only obtain RCS curves and has difficulty in defect location.

[0017] 2. High adaptability and flexibility: The podded radar system adopts a standardized and detachable design, which can be adapted to a variety of aircraft of the same model through a universal mounting interface, and supports the rapid replacement of radar pods of different frequency bands, which can meet the testing needs of multiple frequency bands and multiple platforms; at the same time, the flight strategy of dual-aircraft formation can be flexibly adjusted according to the test mission, which is suitable for both airborne test scenarios and ground-assisted verification scenarios, with outstanding practicality and scalability.

[0018] 3. High testing efficiency and reliability: This invention achieves real-time information sharing and collaborative synchronization between the two aircraft through a tactical data link, ensuring consistency in measurement timing and reducing data deviation; the design of mutual illumination measurement between the two aircraft can complete the scattering characteristics test of the two aircraft in a single flight mission, greatly improving testing efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of measuring the forward / backward scattering characteristics of a dual-aircraft formation according to a specific embodiment of the present invention; Figure 2 is a schematic diagram of the lateral scattering characteristics of a dual-aircraft lateral formation measurement according to a specific embodiment of the present invention; Figure 3 is a schematic diagram of two-dimensional radar image acquisition by dual-machine measurement according to a specific embodiment of the present invention. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] This invention primarily involves constructing a dual-aircraft formation for scattering characteristic testing. Each aircraft is equipped with a forward-facing pod at the wingtip of its leading edge and a rearward-facing pod at the wingtip of its trailing edge. Both pods integrate a complete radar transmitter and receiver, capable of independently transmitting radar signals, receiving scattered signals, and performing preliminary processing. The aircraft are equipped with a Global Positioning System (GPS) and a tactical data link for precise positioning and the sharing and coordination of critical information. This invention employs multi-mode flight strategies, including front-to-back formation, lateral formation, and dynamic formation, to enable mutual illumination measurements between the two aircraft. This allows for comprehensive acquisition of the target aircraft's forward, rearward, lateral, and all-angle radar scattering characteristic signals. Combined with echo data processing technology, high-precision two-dimensional radar images are generated to accurately locate electromagnetic scattering defects. This invention features multi-platform adaptability and multi-frequency band compatibility, providing scientific and reliable technical support for the periodic diagnosis, evaluation, and optimization of the stealth performance of stealth aircraft.

[0022] For details, see Figures 1-3 The diagrams show multi-mode flight strategies using the two-aircraft formation of the present invention, including front-to-back formation, lateral formation, and dynamic formation.

[0023] A system for verifying the scattering characteristics of a target by aerial escort includes at least two aircraft for formation flight. Each aircraft has a forward pod at the leading edge wingtip and a rearward pod at the trailing edge wingtip. Both the forward and rearward pods integrate a complete radar transmitter and receiver. The radar transmitter is used to transmit radar wave detection signals; The receiver is used to capture radar-scattered echo signals; The aircraft also includes a global positioning system and a tactical data link; The global positioning system is used to accurately locate the two aircraft. The tactical data link is used to enable real-time sharing and coordinated synchronization of position, speed and time information between the two aircraft, ensuring consistency of measurement timing.

[0024] Therefore, in this invention, two aircraft flying in formation can use the forward and / or backward pods to measure the air scattering characteristics of another aircraft in flight while in escort mode. This not only obtains radar cross section curves but also radar scattering images, and the measurement path is flexible and the measurement methods are diverse.

[0025] Furthermore, the global positioning system includes at least one of GPS, BeiDou, and Galileo.

[0026] The tactical data link includes at least one of Link-16 and TTNT, and has anti-jamming and high-bandwidth data transmission capabilities.

[0027] Furthermore, both the forward and rearward pods are standardized detachable structures that connect to the aircraft wings via universal mounting interfaces. They can also be replaced with radar pods of different frequency bands according to testing requirements, adapting to various commonly used radar frequency bands such as L, S, C, X, and Ku.

[0028] The forward and backward pods also have pitch and yaw angle adjustment functions, which can adjust the radar measurement angle during flight to obtain more test data under test conditions.

[0029] This invention further discloses a method for measuring the scattering characteristics of an aerial escort verification target, which is implemented using the system for measuring the scattering characteristics of an aerial escort verification target disclosed above. The method is as follows: By changing the order and flight attitude of the aircraft in the multi-mode formation flight, and using forward and / or backward pods to perform measurements, the forward and backward scattering characteristics, side scattering characteristics, and two-dimensional radar image acquisition verifications are completed.

[0030] It should be noted that the radar in the forward or rearward pod used in this invention is different from the radar in the nose radome of aircraft such as fighter jets. The radar in the nose radome is mainly a phased array radar, which cannot be tested. In contrast, this invention mainly uses pulse radar, which can perform scattering characteristic tests to obtain radar cross-section curves and radar scattering images.

[0031] Among them, see Figure 1 The forward and backward scattering characteristics are verified as follows: The first step is to plan the flight path, control the two aircraft to start and fly in formation, so that the first aircraft is located at a predetermined distance in front of the second aircraft (this distance is determined by optimizing the radar detection range and signal strength), and maintain the stability of the formation; The second step involves the airborne control system issuing measurement commands to start the first aircraft and transmit radar wave detection signals to the radar transmitter and receiver in the pod, while the receiver captures and records the forward radar scattering characteristic signal of the second aircraft. The third step is to simultaneously activate the radar transmitter and receiver in the forward pod of the second aircraft to transmit radar wave detection signals to the first aircraft, and capture and record the rearward radar scattering characteristic signals of the first aircraft. The fourth step is to transmit the scattering characteristic signals acquired by the two aircraft to the data processing center through the tactical data link. After processing the signals, the radar scattering characteristic curves of the target are obtained, and the electromagnetic scattering defects of the two aircraft are initially located. The fifth step is to adjust the flight attitude and flight path of the two aircraft so that the second aircraft moves to a preset distance in front of the first aircraft and re-stabilizes the formation. Step 6: Repeat steps 2 to 4, using the forward pod of the first aircraft for radar detection, measuring and processing the backward radar scattering characteristic signal of the second aircraft, and using the backward pod of the second aircraft for radar detection, measuring and processing the forward radar scattering characteristic signal of the first aircraft. The seventh step is to detect and locate the electromagnetic scattering defects of the first and second aircraft based on the radar scattering characteristic signals returned by the two aircraft.

[0032] See Figure 2 The lateral scattering characteristics are verified as follows: First, control the two aircraft to adjust their formation attitude and maintain lateral parallel flight, so that the second aircraft is located at a predetermined lateral distance to the side of the first aircraft, ensuring that the lateral scattering signal is unobstructed and within the effective range of radar detection; Subsequently, the radar transmitter and receiver in the forward pod of the second aircraft were activated to continuously transmit detection signals to the first aircraft, capturing and recording its lateral radar scattering characteristic signals; Finally, the positions of the two aircraft were adjusted so that the first aircraft was located to the side of the second aircraft. The above measurement operations were repeated to complete the comprehensive acquisition of the lateral scattering data of the two aircraft and to achieve complete verification of the lateral scattering characteristics.

[0033] To achieve visualized localization of scattering defects, this invention further designs a dynamic formation flight measurement process.

[0034] See Figure 3The two-dimensional radar image acquisition and verification is as follows: First, control the two aircraft to fly in formation, so that the second aircraft is initially located at a preset position to the right rear of the first aircraft, ensuring that the radar signal can effectively illuminate the target without obstruction; Subsequently, the second aircraft smoothly passed behind the first aircraft along a pre-set smooth trajectory, eventually reaching the pre-set position on the left rear, maintaining a relatively stable formation throughout the process. During the flight, the radar transmitter and receiver in the forward pod of the second aircraft were continuously activated to maintain continuous illumination of the first aircraft, simultaneously acquiring continuous echo data under different positional relationships. Using the echo data, a high-resolution two-dimensional radar image of the first aircraft was generated after processing. Finally, the positions of the two aircraft were adjusted so that the first aircraft moved to the side and rear of the second aircraft. The above operation was repeated to obtain a two-dimensional radar image of the second aircraft.

[0035] By analyzing the abnormal scattering center of the two-dimensional radar image of the aircraft target, the physical location of electromagnetic scattering defects on the aircraft surface can be accurately located, providing an intuitive basis for defect repair.

[0036] In summary, the present invention has the following advantages: 1. Comprehensive and accurate measurement: This invention, through a dual-aircraft escort design, breaks through the angle limitations of ground radar testing, achieving comprehensive measurement of radar scattering characteristics across all angles (all directions and all pitch angles) in the forward, backward, and lateral directions. The measurement process reflects the actual flight state of a real aircraft, reflecting the impact of dynamic factors such as engine operation, component vibration, and wing pitch angle on scattering characteristics, and the acquired data is more consistent with actual application scenarios. Combined with high-resolution two-dimensional radar images, it achieves precise location of scattering defects, solving the problem that traditional testing can only obtain RCS curves and has difficulty in defect location.

[0037] 2. High adaptability and flexibility: The podded radar system adopts a standardized and detachable design, which can be adapted to a variety of aircraft of the same model through a universal mounting interface, and supports the rapid replacement of radar pods of different frequency bands, which can meet the testing needs of multiple frequency bands and multiple platforms; at the same time, the flight strategy of dual-aircraft formation can be flexibly adjusted according to the test mission, which is suitable for both airborne test scenarios and ground-assisted verification scenarios, with outstanding practicality and scalability.

[0038] 3. High testing efficiency and reliability: This invention achieves real-time information sharing and collaborative synchronization between the two aircraft through a tactical data link, ensuring consistency in measurement timing and reducing data deviation; the design of mutual illumination measurement between the two aircraft can complete the scattering characteristics test of the two aircraft in a single flight mission, greatly improving testing efficiency.

[0039] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A system for aerial escort verification of target scattering characteristics, comprising at least two aircraft for formation flying, characterized in that: Each of the aforementioned aircraft is equipped with a forward pod at the leading edge wingtip and a rearward pod at the trailing edge wingtip, and both the forward and rearward pods integrate a complete radar transmitter and receiver. The radar transmitter is used to transmit radar wave detection signals; The receiver is used to capture radar-scattered echo signals; The aircraft also includes a global positioning system and a tactical data link; The global positioning system is used to accurately locate the two aircraft. The tactical data link is used to enable real-time sharing and coordinated synchronization of position, speed and time information between the two aircraft, ensuring consistency of measurement timing.

2. The system according to claim 1, characterized in that: The global positioning system includes at least one of GPS, BeiDou, and Galileo.

3. The system according to claim 1, characterized in that: The tactical data link includes at least one of Link-16 and TTNT, and has anti-jamming and high-bandwidth data transmission capabilities.

4. The system according to claim 1, characterized in that: Both the forward and rearward pods are standardized detachable structures that connect to the aircraft wings via universal mounting interfaces. They can be replaced with radar pods of different frequency bands according to testing requirements, and are compatible with a variety of commonly used radar frequency bands such as L, S, C, X, and Ku.

5. The system according to claim 4, characterized in that: The forward and backward pods also have pitch and yaw angle adjustment functions.

6. A method for aerial escort verification of target scattering characteristics based on the system described in any one of claims 1-5, characterized in that, include: By changing the order and flight attitude of the aircraft in the multi-mode formation flight, and using forward and / or backward pods to perform measurements, the forward and backward scattering characteristics, side scattering characteristics, and two-dimensional radar image acquisition verifications are completed.

7. The method according to claim 6, characterized in that: The forward and backward scattering characteristics were verified as follows: The first step is to plan the flight path, control the two aircraft to start and fly in formation, so that the first aircraft is at a predetermined distance in front of the second aircraft, and maintain the stability of the formation; The second step involves starting the first aircraft and then transmitting radar wave detection signals to the second aircraft via the radar transmitter and receiver inside the pod. At the same time, the receiver captures and records the forward radar scattering characteristic signal of the second aircraft. The third step is to simultaneously activate the radar transmitter and receiver in the forward pod of the second aircraft to transmit radar wave detection signals to the first aircraft, and capture and record the rearward radar scattering characteristic signals of the first aircraft. The fourth step is to transmit the scattering characteristic signals acquired by the two aircraft to the data processing center through the tactical data link. After processing the signals, the radar scattering characteristic curves of the target are obtained, and the electromagnetic scattering defects of the two aircraft are initially located. The fifth step is to adjust the flight attitude and flight path of the two aircraft so that the second aircraft moves to a preset distance in front of the first aircraft and re-stabilizes the formation. The sixth step involves using the forward pod of the first aircraft to conduct radar detection, measuring and processing the backward radar scattering characteristic signal of the second aircraft, and then using the backward pod of the second aircraft to conduct radar detection, measuring and processing the forward radar scattering characteristic signal of the first aircraft. The seventh step is to detect and locate the electromagnetic scattering defects of the first and second aircraft based on the radar scattering characteristic signals returned by the two aircraft.

8. The method according to claim 6, characterized in that: The lateral scattering characteristics are verified as follows: First, control the two aircraft to adjust their formation attitude and maintain lateral parallel flight, so that the second aircraft is located at a predetermined lateral distance to the side of the first aircraft, ensuring that the lateral scattering signal is unobstructed and within the effective range of radar detection; Subsequently, the radar transmitter and receiver in the forward pod of the second aircraft were activated to continuously transmit detection signals to the first aircraft, capturing and recording its lateral radar scattering characteristic signals; Finally, the positions of the two aircraft were adjusted so that the first aircraft was located to the side of the second aircraft. The above measurement operations were repeated to complete the comprehensive acquisition of the lateral scattering data of the two aircraft and to achieve complete verification of the lateral scattering characteristics.

9. The method according to claim 6, characterized in that: The two-dimensional radar image acquisition verification is as follows: First, control the two aircraft to fly in formation, so that the second aircraft is initially located at a preset position to the right rear of the first aircraft, ensuring that the radar signal can effectively illuminate the target without obstruction; Subsequently, the second aircraft smoothly passed behind the first aircraft along a pre-set, smooth trajectory, eventually reaching a pre-set position on the left rear, maintaining relative formation stability throughout the process. During flight, the radar transmitter and receiver in the forward-facing pod of the second aircraft were continuously activated to maintain continuous illumination of the first aircraft, simultaneously acquiring continuous echo data under different positional relationships. Using the echo data, a high-resolution two-dimensional radar image of the first aircraft was generated. Finally, the positions of the two aircraft were adjusted so that the first aircraft moved to the side and rear of the second aircraft. The above operation was repeated to obtain a two-dimensional radar image of the second aircraft.

10. The method according to claim 6, characterized in that: By analyzing two-dimensional radar images and combining them with radar scattering characteristic signals, the physical location of electromagnetic scattering defects on the surface of the aircraft can be accurately determined.

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