A dual-station RCS measurement method

Abstract

The present application relates to the field of radar detection technology, and in particular to a dual-station RCS measurement method. The measurement method is applied to a dual-station RCS measurement system, including: a transmitting station, a receiving station, a signal source, a first receiver, a second receiver, a first link, a second link, and a third link; wherein the first link includes a first ROF module, a power amplifier, a directional coupler, and a transmitting antenna for transmitting a measurement signal; the second link includes a second ROF module for transmitting a reference signal; the third link includes a receiving antenna and a low-noise amplifier for transmitting an echo signal; the measurement method includes: connecting each device in the dual-station RCS measurement system; calibrating the dual-station RCS measurement system using a standard body to obtain a calibrated dual-station RCS measurement system; and using the calibrated dual-station RCS measurement system to perform dual-station RCS measurement of a target. The dual-station RCS measurement method provided in the present application can reduce the power loss caused by long-distance signal transmission, has a long transmission distance, and a simple measurement system.

Description

Technical Field

[0001] The present application relates to the field of radar detection technology, and in particular to a dual-station RCS measurement method. Background Art

[0002] Radar cross section (RCS) is an important characteristic of radar targets. In actual military applications, most stealth targets are often single-station stealth, that is, the radar wave reflected by the target in the incident direction of the radar wave is very weak, thus achieving a stealth effect that cannot be detected by radar; however, most stealth targets often cannot achieve stealth effect in other directions. Therefore, dual-station RCS measurement is very necessary for stealth and anti-stealth research.

[0003] In traditional dual-station RCS measurement systems, the signal transmission system is often located near the transmitting antenna, and the receiving antenna is often located on a scanning frame that can be moved to change the station angle. There is a long distance between the signal receiving system and the signal source. Therefore, when the RF signal is transmitted in the cable, it will produce strong loss, and the loss value increases linearly with the cable length, which greatly compresses the test capability of the system and makes the existing measurement system unable to achieve long-distance signal reception.

[0004] Therefore, there is an urgent need for a dual-station RCS measurement system suitable for long distances to solve the above problems. Summary of the invention

[0005] The present application provides a dual-station RCS measurement method, which can reduce the power loss caused by long-distance signal transmission. The RCS measurement system built using this method has a simple structure and a long transmission distance.

[0006] The embodiment of the present application provides a dual-station RCS measurement method, which is applied to a dual-station RCS measurement system, wherein the dual-station RCS measurement system includes: a transmitting station, a receiving station, a signal source, a first receiver, a second receiver, a first link, a second link, and a third link; wherein the first link includes a first ROF module, a power amplifier, a directional coupler, and a transmitting antenna, and is used to transmit a measurement signal; the second link includes a second ROF module, and is used to transmit a reference signal; the third link includes a receiving antenna and a low noise amplifier, and is used to transmit an echo signal; the measurement method includes:

[0007] Connecting various devices in the dual-station RCS measurement system;

[0008] Using a standard object to calibrate the bistatic RCS measurement system to obtain a calibrated bistatic RCS measurement system;

[0009] The calibrated bistatic RCS measurement system is used to perform bistatic RCS measurement of a target.

[0010] In one possible design, the first ROF module includes a first radio frequency / optical converter and a first optical / radio frequency converter; the second ROF module includes a second radio frequency / optical converter and a second optical / radio frequency converter;

[0011] The first RF / optical converter and the second RF / optical converter are used to convert RF signals into optical signals, and the optical signals are transmitted through optical fibers to reduce power loss during transmission;

[0012] The first optical / RF converter and the second optical / RF converter are used to convert optical signals into RF signals so as to connect the RF signals to the input end of the power amplifier or the first receiver.

[0013] In one possible design, the second receiver is installed at one side of the receiving station to shorten the transmission distance of the third link and reduce power loss during transmission.

[0014] In a possible design, before connecting the devices in the dual-station RCS measurement system, the method further includes:

[0015] The dual-station angle relationship between the receiving station and the transmitting station is adjusted and determined.

[0016] In one possible design, the connecting of the devices in the dual-station RCS measurement system includes:

[0017] Connecting the first link; connecting the measurement signal generated by the signal source to the input end of the first ROF module, and connecting the output end of the first ROF module to the input end of the power amplifier to increase the power of the measurement signal; connecting the output end of the power amplifier to the input end of the directional coupler, and connecting the first output end of the directional coupler to the transmitting antenna to transmit the measurement signal generated by the signal source to the target to be measured through the transmitting antenna;

[0018] Connecting the second link; connecting the second output end of the directional coupler to the input end of the second ROF module, and connecting the output end of the second ROF module to the first receiver, so as to transmit a reference signal to the first receiver, wherein the measurement signal and the reference signal have time synchronization and coherence, and measuring the reference signal is conducive to removing the power drift in the first link;

[0019] The third link is connected; the receiving antenna is connected to the input end of the low noise amplifier, and the output end of the low noise amplifier is connected to the second receiver to transmit the echo signal generated by the target to the second receiver.

[0020] In a possible design, before calibrating the dual-station RCS measurement system using a standard body, the method further includes:

[0021] Each device in the dual-station RCS measurement system is turned on and preheated.

[0022] In one possible design, calibrating the bistatic RCS measurement system using a standard body includes:

[0023] The measurement signal generated by the signal source is connected to the first ROF module, and the measurement signal is converted and transmitted by the first ROF module and then connected to the power amplifier to amplify the power of the measurement signal;

[0024] Connecting the power-amplified measurement signal to the directional coupler;

[0025] Connecting the measurement signal of the first output terminal of the directional coupler to the transmitting antenna, and transmitting the measurement signal to the standard body through the transmitting antenna;

[0026] Connecting a reference signal at the second output end of the directional coupler to the second ROF module, and connecting the reference signal to the first receiver after conversion and transmission by the second ROF module, so as to remove power drift in the first link;

[0027] The receiving antenna receives the echo signal generated by the standard body, and the echo signal is amplified by the low noise amplifier and then connected to the second receiver;

[0028] Acquiring and storing the echo signals acquired by the first receiver and the second receiver, and performing cancellation and time domain software gate processing to obtain the measured value of the standard body;

[0029] The bistatic RCS measurement system is calibrated according to the theoretical value of the standard body and the measured value of the standard body to obtain a calibrated bistatic RCS measurement system.

[0030] In one possible design, performing bistatic RCS measurement of a target using the calibrated bistatic RCS measurement system includes:

[0031] The measurement signal generated by the signal source is connected to the first ROF module, and the measurement signal is converted and transmitted by the first ROF module and then connected to the power amplifier to amplify the power of the measurement signal;

[0032] Connecting the power-amplified measurement signal to the directional coupler;

[0033] Connecting the measurement signal of the first output terminal of the directional coupler to the transmitting antenna, and transmitting the measurement signal to the target to be measured through the transmitting antenna;

[0034] Connecting the reference signal at the second output end of the directional coupler to the second ROF module, and connecting the reference signal to the first receiver after being converted and transmitted by the second ROF module;

[0035] The receiving antenna receives the echo signal generated by the target to be measured, and the echo signal is amplified by the low noise amplifier and then connected to the second receiver;

[0036] The echo signals acquired by the first receiver and the second receiver are collected and stored, and cancellation and time domain software gate processing are performed to obtain the RCS value of the target to be measured.

[0037] By adopting the above technical solution, the dual-station RCS measurement method described in the present invention has the following beneficial effects:

[0038] 1) The present invention can convert radio frequency signals into optical signals by introducing the first ROF module and the second ROF module, so that the optical signals are transmitted in the optical fiber, which can reduce the power loss of the measurement signal during long-distance transmission, and the transmission distance is long, and the transmission distance without relay can reach 1500 meters;

[0039] 2) The present invention uses optical fiber to transmit the measurement signal. Due to the low power loss, there is no need to use a multi-stage amplifier in the test link, and the measurement system is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 is a schematic diagram of a dual-station RCS measurement method provided by an embodiment of the present invention;

[0042] Figure 2 Schematic diagram of a dual-station RCS measurement system provided by an embodiment of the present invention.

[0043] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0044] The present application is described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0045] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0047] In the related art, in order to reduce the power loss caused by long-distance transmission of RF signals, a multi-stage amplifier is usually used to amplify and equalize the RF signals on the third link. However, the measurement system built using this method is too complicated, and the general transmission distance cannot exceed 50 meters. Therefore, this method is not suitable for long-distance dual-station RCS measurement systems.

[0048] In order to solve this technical problem, we can consider using ROF technology in the transmission line to convert the RF signal into an optical signal and use optical fiber for signal transmission to reduce the power loss caused by long-distance cable transmission.

[0049] like Figure 1 As shown, an embodiment of the present invention provides a dual-station RCS measurement method, which is applied to a dual-station RCS measurement system.

[0050] like Figure 2 As shown, the dual-station RCS measurement system includes: a transmitting station, a receiving station, a signal source, a first receiver, a second receiver, a first link, a second link and a third link; wherein the first link includes a first ROF module, a power amplifier, a directional coupler and a transmitting antenna, and is used to transmit a measurement signal; the second link includes a second ROF module, and is used to transmit a reference signal; the third link includes a receiving antenna and a low noise amplifier, and is used to transmit an echo signal;

[0051] The method comprises the following steps:

[0052] Step 100: Connecting various devices in the dual-station RCS measurement system;

[0053] Step 102: calibrating the bistatic RCS measurement system using a standard object to obtain a calibrated bistatic RCS measurement system;

[0054] Step 104: Use the calibrated bistatic RCS measurement system to perform bistatic RCS measurement of the target.

[0055] In this embodiment, by introducing the first ROF module and the second ROF module, the radio frequency signal can be converted into an optical signal so that the optical signal is transmitted in the optical fiber. On the one hand, the power loss of the measurement signal during long-distance transmission can be reduced and the transmission distance can be increased; on the other hand, there is no need to use a multi-stage amplifier in the test link, and the measurement system is simple.

[0056] It should be noted that the signal source is any device that can generate a measurement signal. For example, the signal source can be a vector network analyzer with an integrated dual-channel receiver, which has the functions of transmitting signals and receiving measurement data. This application does not specifically limit the signal source. In addition, the RCS test method of this application is applicable to measurement signals of any frequency band, especially to measurement signals within the 0.5-40 GHZ frequency band.

[0057] In some embodiments, Figure 2 As shown, the first ROF module includes a first radio frequency / optical converter and a first optical / radio frequency converter; the second ROF module includes a second radio frequency / optical converter and a second optical / radio frequency converter;

[0058] The first RF / optical converter and the second RF / optical converter are used to convert the RF signal into an optical signal, and the optical signal is transmitted through the optical fiber to reduce power loss during transmission;

[0059] The first optical / RF converter and the second optical / RF converter are used to convert the optical signal into a RF signal so as to connect the RF signal to the input end of the power amplifier or the first receiver.

[0060] In this embodiment, by using ROF (radio-over-fiber) technology, the radio frequency signal is converted into an optical signal, which is transmitted through the optical fiber. The receiving end then converts the optical signal into a radio frequency signal, which has the advantages of long transmission distance and low transmission signal power loss.

[0061] In some implementations, the second receiver is installed at the receiving station side to shorten the transmission distance of the third link and reduce power loss during transmission.

[0062] In this embodiment, in order to facilitate the change of the station angle of the receiving antenna, the receiving antenna is arranged on a scanning frame that can be moved to change the station angle, and for the convenience of operation, the signal source, the first receiver and the second receiver are placed on the ground. Therefore, there is a large height difference between the receiving antenna and the second receiver, and the height difference will cause the bending of the transmission cable. However, when radio frequency signal transmission is adopted, the bending of the radio frequency cable will not affect the stability of the measurement signal, and when optical fiber transmission is adopted, the bending of the optical fiber will affect the stability of the measurement phase. Therefore, in this embodiment, the second receiver is installed on one side of the receiving station to shorten the transmission distance of the third link. In this link, the receiving antenna and the low noise amplifier are connected by a radio frequency cable, and then the measurement signal is connected to the second receiver. The link is simple and the measurement accuracy is high. In addition, in order to facilitate centralized operation and management, the signal source and the first receiver are also arranged on one side of the receiving station. Although the transmission distance of the first link and the second link is long, ROF technology can be used to reduce the power loss during transmission.

[0063] Before executing step 100, in some embodiments, the method further includes:

[0064] Adjust and determine the dual-station angle relationship between the receiving station and the transmitting station.

[0065] In this embodiment, the angle between the two stations can be adjusted to a preset angle to measure the scattering conditions of the target in various directions. The user can set the angle between the two stations according to actual test needs, for example, 30° to 100°, which is not specifically limited in this application.

[0066] In some embodiments, step 100 includes:

[0067] Connecting the first link; connecting the measurement signal generated by the signal source to the input end of the first ROF module, and connecting the output end of the first ROF module to the input end of the power amplifier to increase the power of the measurement signal; connecting the output end of the power amplifier to the input end of the directional coupler, and connecting the first output end of the directional coupler to the transmitting antenna to transmit the measurement signal generated by the signal source to the target to be measured through the transmitting antenna;

[0068] Connecting the second link; connecting the second output end of the directional coupler to the input end of the second ROF module, and connecting the output end of the second ROF module to the first receiver to transmit the reference signal to the first receiver, wherein the measurement signal and the reference signal have time synchronization and coherence, and measuring the reference signal is conducive to removing the power drift in the first link;

[0069] The third link is connected; the receiving antenna is connected to the input end of the low noise amplifier, and the output end of the low noise amplifier is connected to the second receiver to transmit the echo signal generated by the target to the second receiver.

[0070] In this embodiment, after completing the equipment layout, the interfaces of each device are correctly connected using radio frequency cables or optical fibers to ensure the stability of the test system.

[0071] Before executing step 102, in some embodiments, the process further includes: starting each device in the dual-station RCS measurement system and preheating each device to avoid damage to the device and influence on the accuracy of the measurement result caused by sudden startup.

[0072] With respect to step 102, in some implementations, it includes:

[0073] The measurement signal generated by the signal source is connected to the first ROF module, and the measurement signal is converted and transmitted by the first ROF module and then connected to the power amplifier to amplify the power of the measurement signal;

[0074] Connect the power-amplified measurement signal to the directional coupler;

[0075] Connecting the measurement signal at the first output end of the directional coupler to the transmitting antenna, and transmitting the measurement signal to the standard body through the transmitting antenna;

[0076] Connecting the reference signal at the second output end of the directional coupler to the second ROF module, and connecting the reference signal to the first receiver after conversion and transmission by the second ROF module to remove the power drift of the system before the power amplifier;

[0077] The echo signal generated by the standard body is received by a receiving antenna, and the echo signal is amplified by a low noise amplifier and then connected to a second receiver;

[0078] The echo signals acquired by the first receiver and the second receiver are collected and stored, and cancellation and time domain software gate processing are performed to obtain the measured value of the standard body;

[0079] The dual-station RCS measurement system is calibrated according to the theoretical value of the standard body and the measured value of the standard body to obtain a calibrated dual-station RCS measurement system.

[0080] In this embodiment, the bistatic RCS measurement system is calibrated using a standard body, which can eliminate system errors and path errors, thereby improving the accuracy of the measurement system.

[0081] In some implementations, step 104 includes:

[0082] The measurement signal generated by the signal source is connected to the first ROF module, and the measurement signal is converted and transmitted by the first ROF module and then connected to the power amplifier to amplify the power of the measurement signal;

[0083] Connect the power-amplified measurement signal to the directional coupler;

[0084] Connecting the measurement signal at the first output end of the directional coupler to the transmitting antenna, and transmitting the measurement signal to the target to be measured through the transmitting antenna;

[0085] Connecting the reference signal at the second output end of the directional coupler to the second ROF module, and connecting the reference signal to the first receiver after being converted and transmitted by the second ROF module;

[0086] The receiving antenna receives the echo signal generated by the target to be measured, and the echo signal is amplified by a low noise amplifier and then connected to the second receiver;

[0087] The echo signals acquired by the first receiver and the second receiver are collected and stored, and cancellation and time domain software gate processing are performed to obtain the RCS value of the target to be measured.

[0088] In this embodiment, the ROF technology is used for signal transmission in the calibrated dual-station RCS measurement system, which can reduce the power loss of the measurement signal during long-distance transmission. The transmission distance can reach 1500 meters, and the measurement accuracy will be high.

[0089] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-station RCS measurement method, characterized in that: Applied to a dual-station RCS measurement system, the dual-station RCS measurement system includes: a transmitting station, a receiving station, a signal source, a first receiver, a second receiver, a first link, a second link and a third link; wherein the first link includes a first ROF module, a power amplifier, a directional coupler and a transmitting antenna for transmitting a measurement signal; the second link includes a second ROF module for transmitting a reference signal; the third link includes a receiving antenna and a low-noise amplifier for transmitting an echo signal; the measurement method includes: Connecting various devices in the dual-station RCS measurement system; Using a standard object to calibrate the bistatic RCS measurement system to obtain a calibrated bistatic RCS measurement system; The calibrated bistatic RCS measurement system is used to perform bistatic RCS measurement of a target.

2. The measuring method according to claim 1, characterized in that: The first ROF module includes a first radio frequency / optical converter and a first optical / radio frequency converter; the second ROF module includes a second radio frequency / optical converter and a second optical / radio frequency converter; The first RF / optical converter and the second RF / optical converter are used to convert RF signals into optical signals, and the optical signals are transmitted through optical fibers to reduce power loss during transmission; The first optical / RF converter and the second optical / RF converter are used to convert optical signals into RF signals so as to connect the RF signals to the input end of the power amplifier or the first receiver.

3. The measuring method according to claim 1, characterized in that: The second receiver is installed at the receiving station side to shorten the transmission distance of the third link and reduce the power loss during the transmission process.

4. The measuring method according to claim 1, characterized in that: Before connecting the devices in the dual-station RCS measurement system, the method further includes: The dual-station angle relationship between the receiving station and the transmitting station is adjusted and determined.

5. The measuring method according to claim 1, characterized in that: The device in the dual-station RCS measurement system is connected, including: Connecting the first link; connecting the measurement signal generated by the signal source to the input end of the first ROF module, and connecting the output end of the first ROF module to the input end of the power amplifier to increase the power of the measurement signal; connecting the output end of the power amplifier to the input end of the directional coupler, and connecting the first output end of the directional coupler to the transmitting antenna to transmit the measurement signal generated by the signal source to the target to be measured through the transmitting antenna; Connecting the second link; connecting the second output end of the directional coupler to the input end of the second ROF module, and connecting the output end of the second ROF module to the first receiver to transmit a reference signal to the first receiver, wherein the measurement signal and the reference signal have time synchronization and coherence, and measuring the reference signal to remove the power drift in the first link; The third link is connected; the receiving antenna is connected to the input end of the low noise amplifier, and the output end of the low noise amplifier is connected to the second receiver to transmit the echo signal generated by the target to the second receiver.

6. The measuring method according to claim 5, characterized in that: Before calibrating the dual-station RCS measurement system using a standard body, the following steps are also included: Each device in the dual-station RCS measurement system is turned on and preheated.

7. The measuring method according to claim 6, characterized in that: The method of calibrating the dual-station RCS measurement system using a standard body includes: The measurement signal generated by the signal source is connected to the first ROF module, and the measurement signal is converted and transmitted by the first ROF module and then connected to the power amplifier to amplify the power of the measurement signal; Connecting the power-amplified measurement signal to the directional coupler; Connecting the measurement signal of the first output terminal of the directional coupler to the transmitting antenna, and transmitting the measurement signal to the standard body through the transmitting antenna; Connecting the reference signal at the second output end of the directional coupler to the second ROF module, and connecting the reference signal to the first receiver after being converted and transmitted by the second ROF module; The receiving antenna receives the echo signal generated by the standard body, and the echo signal is amplified by the low noise amplifier and then connected to the second receiver; Acquiring and storing the echo signals acquired by the first receiver and the second receiver, and performing cancellation and time domain software gate processing to obtain the measured value of the standard body; The bistatic RCS measurement system is calibrated according to the theoretical value of the standard body and the measured value of the standard body to obtain a calibrated bistatic RCS measurement system.

8. The measuring method according to claim 1, characterized in that: The method of performing bi-station RCS measurement of a target by using the calibrated bi-station RCS measurement system comprises: The measurement signal generated by the signal source is connected to the first ROF module, and the measurement signal is converted and transmitted by the first ROF module and then connected to the power amplifier to amplify the power of the measurement signal; Connecting the power-amplified measurement signal to the directional coupler; Connecting the measurement signal of the first output terminal of the directional coupler to the transmitting antenna, and transmitting the measurement signal to the target to be measured through the transmitting antenna; Connecting the reference signal at the second output end of the directional coupler to the second ROF module, and connecting the reference signal to the first receiver after being converted and transmitted by the second ROF module; The receiving antenna receives the echo signal generated by the target to be measured, and the echo signal is amplified by the low noise amplifier and then connected to the second receiver; The echo signals acquired by the first receiver and the second receiver are collected and stored, and cancellation and time domain software gate processing are performed to obtain the RCS value of the target to be measured.

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