A semi-active radar ranging method and a semi-active radar system

Abstract

This application provides a semi-active radar ranging method and a semi-active radar system, relating to the field of radar signal processing technology. When it is determined that the frame start time of the current signal received frame during the target tracking period of the radar receiver cannot be synchronized with the time of the illumination source transmitter, this application constructs a suitable actual straight-wave detection gate for the current signal received frame. This introduces the influence of the straight-wave range cell offset caused by the time asynchrony error into the straight-wave signal filtering ranging process to measure the actual straight-wave range cell of the current signal received frame. Then, based on the aforementioned actual straight-wave range cell, a suitable actual echo detection gate is constructed for the current signal received frame to introduce the influence of the echo range cell offset caused by the time asynchrony error into the echo signal filtering ranging process to measure the actual echo range cell of the current signal received frame. This ensures that the final ranging result has sufficiently strong stability and accuracy.

Description

Technical Field

[0001] This application relates to the field of radar signal processing technology, and more specifically, to a semi-active radar ranging method and a semi-active radar system. Background Technology

[0002] With the continuous development of science and technology, semi-active radar systems, as bistatic radar systems with separate illumination source transmitters and radar receivers, have gradually attracted widespread attention from various industries. For a semi-active radar system, an illumination source transmitter emits electromagnetic waves towards the target object. The radar receiver receives the electromagnetic waves directly from the illumination source transmitter (i.e., the straight-wave signal) and the electromagnetic waves reflected from the target object (i.e., the echo signal). The radar receiver then performs a series of signal processing steps on the received straight-wave and echo signals to obtain target positioning information such as the target object's speed, distance, and offset angle relative to the radar receiver, thereby achieving the detection and tracking effect of the target object.

[0003] It is worth noting that in the actual use of semi-active radar systems, the radar receiver relies on the time delay information between the received signal (including direct wave signal and echo signal) and the transmitted signal from the illumination source transmitter to achieve target location. This requires strict time synchronization between the radar receiver and the illumination source transmitter. However, because the illumination source transmitter and the radar receiver are deployed separately, time synchronization errors such as clock inconsistencies and misaligned frame start times may occur. This causes a deviation in the time reference when the radar receiver processes each frame of received signal, which can easily lead to inter-frame offset in the range dimension during moving target detection for target tracking, affecting the stability and accuracy of the final ranging result. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a semi-active radar ranging method and a semi-active radar system, which can configure a reasonable receiving signal detection gate (including a straight wave detection gate and an echo detection gate) for the radar receiver when the radar receiver and the illumination source transmitter are out of sync. This allows the corresponding receiving signal detection gate to effectively incorporate the range cell offset caused by the time asynchrony error into the moving target detection process for the target tracking object, ensuring that the final ranging result has sufficient stability and accuracy, and avoiding inter-frame offset in the range dimension.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:

[0006] In a first aspect, this application provides a semi-active radar ranging method applied to a radar receiver included in a semi-active radar system, wherein the semi-active radar system further includes an illumination source transmitter, and the ranging method includes:

[0007] During the target tracking period of any radar ranging cycle, it can detect in real time whether it is synchronized with the time of the illumination source transmitter.

[0008] When it is detected that the frame start time of the current signal receiving frame is not synchronized with the time of the illumination source transmitter, the actual straight wave detection gate of the current signal receiving frame is determined according to the historical straight wave distance unit measured for the illumination source transmitter in the previous signal receiving frame, wherein the actual straight wave detection gate size of the current signal receiving frame is greater than the historical straight wave detection gate size of the previous signal receiving frame.

[0009] According to the actual straight wave detection gate, the straight wave signal involved in the current signal reception frame is subjected to signal selection Doppler ranging processing to obtain the actual straight wave distance unit of the current signal reception frame relative to the illumination source transmitter.

[0010] Based on the historical straight wave distance unit, the actual straight wave distance unit, and the historical echo distance unit measured for the target tracking object in the previous signal reception frame, as well as the number of frame intervals between the current signal reception frame and the closest historical valid reception frame, the actual echo detection gate of the current signal reception frame is determined, wherein the measured distance of the historical valid reception frame for the target tracking object meets the object tracking point association threshold requirement.

[0011] According to the actual echo detection gate, signal selective Doppler ranging processing is performed on the echo signal involved in the current signal reception frame to obtain the actual echo distance unit of the current signal reception frame for the target tracking object.

[0012] In an optional implementation, the step of determining the actual straight-wave detection gate of the current signal reception frame based on the historical straight-wave distance unit measured for the illumination source transmitter in the previous signal reception frame includes:

[0013] The historical straight wave distance unit is directly used as the gate center of the actual straight wave detection gate;

[0014] Calculate the expected gate widening of the actual straight wave detection gate relative to the historical straight wave detection gate of the previous signal reception frame;

[0015] The historical straight wave detection gate size of the previous signal reception frame is enlarged according to the desired gate widening amount to obtain the actual straight wave detection gate size.

[0016] In an optional implementation, the step of calculating the expected gate widening of the actual straight-wave detection gate relative to the historical straight-wave detection gate of the previous signal reception frame includes:

[0017] Based on the receiver motion acceleration of the radar receiver and the frame start time interval between two adjacent signal reception frames, calculate the first uniformly accelerated displacement of the radar receiver corresponding to the frame start time interval.

[0018] Half of the first uniformly accelerated displacement is taken as the expected gate widening of the actual straight wave detection gate.

[0019] In an optional implementation, the step of determining the actual echo detection gate of the current signal reception frame based on the historical straight-wave distance unit, the actual straight-wave distance unit, the historical echo distance unit measured for the target tracking object in the previous signal reception frame, and the number of frame intervals between the current signal reception frame and the nearest historical valid reception frame includes:

[0020] Calculate the distance cell difference between the actual straight wave distance cell and the historical straight wave distance cell, and perform an addition operation on the historical echo distance cell and the distance cell difference to obtain the gate center of the actual echo detection gate;

[0021] Based on the number of frame intervals and the frame start time interval between two adjacent signal received frames, calculate the total interval between the current signal received frame and the historical valid received frames;

[0022] Based on the object motion acceleration of the target tracking object and the total interval duration, calculate the second uniformly accelerated displacement of the target tracking object corresponding to the total interval duration;

[0023] Half of the second uniformly accelerated displacement is used as the gate size of the actual echo detection gate.

[0024] In an optional implementation, for the first [number] of a single radar ranging cycle For each received signal frame, when the frame start time is not synchronized with the time of the illumination source transmitter, the object tracking point association threshold requirement corresponding to the received signal frame is expressed by the following inequality:

[0025] ;

[0026] in, Used to indicate the duration of the frame start time interval between two adjacent received signal frames. Used to indicate the first The measured distance matched by each signal received frame to the actual echo distance unit measured for the target tracking object. Used to indicate the first The measured distance matched by the historical echo distance unit measured for the target tracking object in each received signal frame. Used to indicate the first Each received signal frame corresponds to the transceiver distance matched to the actual straight-wave distance unit measured by the transmitter of the illumination source. Used to indicate the first Each received signal frame matches the transceiver distance to the historical straight-wave distance unit measured by the transmitter of the illumination source. Used to represent the receiver motion acceleration of the radar receiver. Used to represent the object motion acceleration of the target being tracked. The range resolution unit is used to represent the radar receiver.

[0027] In an optional implementation, for the first [number] of a single radar ranging cycle For each received signal frame, when the frame start time of the received signal frame is synchronized with the time of the illumination source transmitter, the object tracking point association threshold requirement corresponding to the received signal frame is expressed by the following inequality:

[0028] ;

[0029] in, Used to indicate the duration of the frame start time interval between two adjacent received signal frames. Used to indicate the first The measured distance matched by each signal received frame to the actual echo distance unit measured for the target tracking object. Used to indicate the first The measured distance matched by the historical echo distance unit measured for the target tracking object in each received signal frame. Used to represent the receiver motion acceleration of the radar receiver. Used to represent the object motion acceleration of the target being tracked. The range resolution unit is used to represent the radar receiver.

[0030] In an optional implementation, the ranging method further includes:

[0031] When the frame start time of the current signal reception frame is detected to be synchronized with the time of the illumination source transmitter, the historical straight wave distance unit of the previous signal reception frame is used as the gate center of the actual straight wave detection gate, and the gate size of the actual straight wave detection gate is configured according to the preset straight wave gate size.

[0032] According to the actual straight wave detection gate, the straight wave signal involved in the current signal reception frame is subjected to signal selection Doppler ranging processing to obtain the actual straight wave distance unit of the current signal reception frame relative to the illumination source transmitter.

[0033] The actual echo detection gate of the current signal receiving frame is determined based on the historical echo distance unit of the previous signal receiving frame and the number of frame intervals between the current signal receiving frame and the nearest valid historical receiving frame.

[0034] According to the actual echo detection gate, signal selective Doppler ranging processing is performed on the echo signal involved in the current signal reception frame to obtain the actual echo distance unit of the current signal reception frame for the target tracking object.

[0035] In an optional implementation, the step of determining the actual echo detection gate of the current signal receiving frame based on the historical echo distance unit of the previous signal receiving frame and the number of frame intervals between the current signal receiving frame and the nearest historical valid receiving frame includes:

[0036] The historical echo distance unit is directly used as the gate center of the actual echo detection gate;

[0037] Based on the number of frame intervals and the frame start time interval between two adjacent signal received frames, calculate the total interval between the current signal received frame and the historical valid received frames;

[0038] Based on the object motion acceleration of the target tracking object and the total interval duration, calculate the second uniformly accelerated displacement of the target tracking object corresponding to the total interval duration;

[0039] Half of the second uniformly accelerated displacement is used as the gate size of the actual echo detection gate.

[0040] In an optional implementation, the ranging method further includes:

[0041] During the illumination source rest period of any radar ranging cycle, an equivalent distance of zero radio frequency calibration signal is generated, and coupled echo calibration signals are obtained by coupling the radio frequency calibration signal through the antenna and differential converter of the three channels of echo and difference.

[0042] Based on the radio frequency calibration signal, the coupled echo calibration signals of the echo and differential channels are sequentially subjected to digital quadrature downconversion and signal pulse compression processing to obtain the zero-pitch mapping calibration signals of the echo and differential channels respectively.

[0043] Detect whether the actual distance cells of the echo and differential three channels are consistent at the point of maximum signal amplitude of the corresponding zero-distance mapping calibration signal;

[0044] If the actual distance units at the maximum signal amplitude points of the echo and differential channels are not consistent, the difference between the azimuth and elevation difference channels and the actual calibration signal of the beam channel is calculated relative to the actual calibration signal of the beam channel. The receiving channel parameters of the azimuth and elevation difference channels are compensated according to the calculated actual calibration signal differences to keep the receiving channel parameters of the echo and differential channels consistent.

[0045] Secondly, this application provides a semi-active radar system, the radar system including a radar receiver and an illumination source transmitter, wherein the illumination source transmitter is used to transmit electromagnetic waves toward a target being tracked; the radar receiver is used to receive a direct wave signal emitted from the illumination source transmitter and to receive an echo signal reflected by the target being tracked.

[0046] The radar receiver stores a computer program and can execute the computer program to implement the semi-active radar ranging method described in any of the foregoing embodiments.

[0047] In this case, the beneficial effects of the embodiments of this application may include the following:

[0048] When this application determines that the start time of the current signal received frame during the target tracking period cannot be synchronized with the time of the illumination source transmitter, it constructs an actual straight-wave detection gate for the current signal received frame based on the historical straight-wave range cells measured against the illumination source transmitter in the previous signal received frame. This actual straight-wave detection gate size is larger than the historical straight-wave detection gate size of the previous signal received frame. This incorporates the straight-wave range cell offset caused by the time asynchrony error into the Doppler ranging process of selecting straight-wave signals, thereby accurately measuring the actual straight-wave range cells in the straight-wave range-Doppler spectrum of the current signal received frame. Then, based on the aforementioned historical straight-wave range cells, the aforementioned actual straight-wave range cells, the historical echo range cells measured against the target tracking object in the previous signal received frame, and the historical valid reception cells of the current signal received frame and the closest historical data that meets the object tracking point correlation threshold requirement, the application... The number of frame intervals between received frames is used to construct the actual echo detection gate for the current signal received frame. This allows the corresponding actual straight-wave detection gate to incorporate the echo range cell offset caused by time asynchrony error into the process of screening echo signals for Doppler ranging. This enables accurate measurement of the actual echo range cell in the echo range-Doppler spectrum of the current signal received frame. By calculating the actual distance difference between the actual straight-wave range cell and the actual echo range cell, the true distance between the radar receiver and the target being tracked can be accurately measured. Thus, even when the radar receiver and the illumination source transmitter are out of sync, by configuring a reasonable received signal detection gate, the range cell offset caused by time asynchrony error can be effectively incorporated into the moving target detection process for the target being tracked. This ensures that the final ranging result has sufficient stability and accuracy, and avoids inter-frame offset in the range dimension.

[0049] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the system composition of a semi-active radar system provided in an embodiment of this application;

[0052] Figure 2 This is one of the flowcharts illustrating the semi-active radar ranging method provided in the embodiments of this application;

[0053] Figure 3 for Figure 2 A flowchart illustrating the sub-steps included in step S220;

[0054] Figure 4 for Figure 2 A flowchart illustrating the sub-steps included in step S240;

[0055] Figure 5 A second schematic flowchart of the semi-active radar ranging method provided in the embodiments of this application;

[0056] Figure 6 for Figure 5 A flowchart illustrating the sub-steps included in step S280;

[0057] Figure 7 This is the third flowchart illustrating the semi-active radar ranging method provided in the embodiments of this application.

[0058] Icons: 10 - Semi-active radar system; 11 - Radar receiver; 12 - Illumination source transmitter. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0060] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0061] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0062] In the description of this application, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0063] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0064] Furthermore, it is understood in the description of this application that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0065] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0066] Please refer to Figure 1 , Figure 1This is a schematic diagram of the system composition of a semi-active radar system 10 provided in this application embodiment. In this application embodiment, the semi-active radar system 10 may include a radar receiver 11 and an illumination source transmitter 12, wherein the illumination source transmitter 12 is used to transmit electromagnetic waves to the target being tracked; some of the electromagnetic waves emitted by the illumination source transmitter 12 may directly reach the radar receiver 11 during propagation, and the electromagnetic waves received by the radar receiver 11 in this case are the direct wave signals from the illumination source transmitter 12; while the electromagnetic waves emitted by the illumination source transmitter 12 to the target being tracked are often reflected by the target being tracked, so that the electromagnetic waves reflected by the target being tracked are transmitted to the radar receiver 11, and the electromagnetic waves received by the radar receiver 11 in this case are the echo signals formed by the reflection of the target being tracked. The illumination source transmitter 12 may use a linear frequency-modulated continuous wave (LFMCW) waveform as its externally transmitted electromagnetic wave waveform to effectively improve the range resolution capability of the semi-active radar system 10.

[0067] In this embodiment, the radar receiver 11 may include a main control unit, a straight-wave receiving link, and an echo receiving link. The straight-wave receiving link is used to receive straight-wave signals, and the echo receiving link is used to receive echo signals. The main control unit is electrically connected to the straight-wave receiving link and the echo receiving link, and controls their respective motion states to drive them to receive appropriate electromagnetic wave signals. The main control unit then performs ranging processing on the target object based on the received straight-wave and echo signals, thereby achieving precise positioning of the target object.

[0068] In this case, the received signal (including straight wave signal and echo signal) of the radar receiver 11 is often not delayed from zero kilometers. This is caused by factors such as the signal sampling delay of the radar receiver 11 itself or the asynchronous reception channel. These factors will cause the radar receiver 11 to appear in a non-zero straight wave distance cell (which is used to characterize the distance between the radar receiver 11 and the illumination source transmitter 12) even when the actual distance of the radar receiver 11 relative to the target tracking object is 0. At this time, even if the actual distance of the radar receiver 11 relative to the target tracking object is 0, the corresponding echo signal may appear in a non-zero echo distance cell (which is used to characterize the shortest path length from the radar receiver 11 to the illumination source transmitter 12 via the target tracking object).

[0069] Based on this, before the radar receiver 11 is put into use, the actual distance between the radar receiver 11 and the illumination source transmitter 12 can be set to 0 in the test scenario, and the illumination source transmitter 12 can be turned on to directly shine on the radar receiver 11. The radar receiver 11 records the position of the range cell where the peak value in the range-Doppler spectrum of the corresponding straight wave signal is located. In the subsequent use of the receiver, this position of the range cell can be used as the zero-kilometer reference range cell for straight wave range cell measurement compensation, thereby completing the straight wave receiving link (channel) calibration operation of the radar receiver 11.

[0070] Furthermore, the echo reception link of the radar receiver 11 can be implemented using echo sum and difference three-channel technology, so that the echo reception channels involved in the echo reception link (i.e., the echo sum and difference three channels) can include a beam channel, an azimuth difference channel, and an elevation difference channel. During any radar ranging cycle in actual use, during the illumination source rest period (i.e., the intermittent period when the illumination source transmitter 12 stops transmitting electromagnetic waves), the radar receiver 11 can calibrate and compensate the reception channel parameters (including delay errors and amplitude and phase errors between the echo sum and difference three channels) of the echo sum and difference three channels to keep the reception channel parameters of each echo sum and difference channel as consistent as possible, thereby ensuring that the echo reception data of each echo sum and difference three channel can maintain consistency on the time axis.

[0071] In this embodiment, the main control unit can store a specific computer program related to the semi-active radar ranging function. By executing the specific computer program, when the radar receiver 11 and the illumination source transmitter 12 are out of time, it configures a reasonable receiving signal detection gate (including a straight wave detection gate and an echo detection gate) for the radar receiver 11. This allows the corresponding receiving signal detection gate to effectively incorporate the range cell offset effect (including the straight wave range cell offset effect and the echo range cell offset effect) caused by the time asynchrony error into the moving target detection process for the target tracking object, ensuring that the final ranging result has sufficient stability and accuracy, and avoiding inter-frame offset in the range dimension. In actual use, the illumination source transmitter 12 can periodically transmit synchronization trigger pulse signals to the radar receiver 11 to synchronize with the radar receiver 11.

[0072] Understandable, Figure 1 The block diagram shown is only a schematic diagram of one configuration of the semi-active radar system 10. The semi-active radar system 10 may also include components such as... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown. Figure 1 The components shown can be implemented using hardware, software, or a combination thereof.

[0073] In this application, to ensure that the radar receiver 11 can effectively incorporate the range cell offset caused by time asynchrony error into the moving target detection process when the radar receiver 11 is out of sync with the illumination source transmitter 12, and to ensure that the final ranging result has sufficient stability and accuracy, this application provides a semi-active radar ranging method applied to the radar receiver 11 to achieve the aforementioned objective. The semi-active radar ranging method provided in this application will be described in detail below.

[0074] Please refer to Figure 2 , Figure 2 This is one of the flowcharts illustrating the semi-active radar ranging method provided in this application embodiment. In this application embodiment, Figure 2 The semi-active radar ranging method shown may include steps S210 to S250.

[0075] Step S210: During the target tracking period of any radar ranging cycle, detect in real time whether the device is synchronized with the time of the illumination source transmitter.

[0076] In this embodiment, for the semi-active radar system 10, a single radar ranging cycle can be divided into an illumination source rest period, at least one target object search period (i.e., the search time period during which the radar receiver 11 searches for the target object), and at least one target object tracking period (i.e., the tracking time period during which the radar receiver 11 tracks the target object); wherein, within a certain target object search period, the radar receiver 11 has a first value (greater than or equal to 2) of consecutive signal reception frames that meet the object tracking point association threshold requirement (which is used to constrain the distribution range of measured distance values ​​of different signal reception frames when normally tracking the target object, wherein the measured distance is used to represent When the actual distance between the radar receiver 11 and the target object is reached, the radar receiver 11 will exit the target object search period and enter a target object tracking period. At this time, the radar receiver 11 will change from the target search state to the target tracking state. Conversely, when the radar receiver 11 has a second consecutive value (which is much larger than the first value, for example, the first value is 2 and the second value is 5) of signal reception frames that do not meet the target tracking point association threshold requirement during a target object tracking period, the radar receiver 11 will exit the target object tracking period and enter a target object search period. At this time, the radar receiver 11 will change from the target tracking state to the target search state. Specifically, when a signal reception frame meets the target tracking point association threshold requirement, it indicates that the signal reception frame has not lost track of the target object, and the signal reception frame can be considered a valid reception frame for the radar receiver 11 in tracking the target object.

[0077] In this process, for the first [number] of a single radar ranging cycle For each received signal frame, when the frame start time is not synchronized with the time of the illumination source transmitter 12, the object tracking point association threshold requirement corresponding to the received signal frame is expressed by the following inequality:

[0078] ;

[0079] in, Used to indicate the duration of the frame start time interval between two adjacent received signal frames. Used to indicate the first Each signal receiving frame matches the actual echo distance unit measured for the target tracking object (i.e., the actual distance between the radar receiver 11 and the target tracking object). Used to indicate the first The measured distance matched by the historical echo distance unit measured for the target tracking object in each received signal frame. Used to indicate the first Each signal receiving frame corresponds to the transceiver distance matched to the actual straight-wave distance unit measured by the illumination source transmitter 12 (i.e., the actual distance between the radar receiver 11 and the illumination source transmitter 12). Used to indicate the first Each received signal frame matches the transceiver distance to the historical straight-wave distance unit measured by the transmitter of the illumination source. Used to represent the receiver motion acceleration of the radar receiver 11 Used to represent the object motion acceleration of the target being tracked. The range resolution unit is used to represent the radar receiver 11.

[0080] When the start time of the received signal frame is synchronized with the time of the illumination source transmitter 12, the object tracking point association threshold requirement corresponding to the received signal frame is expressed by the following inequality:

[0081] ;

[0082] in, Used to indicate the duration of the frame start time interval between two adjacent received signal frames. Used to indicate the first The measured distance matched by each signal received frame to the actual echo distance unit measured for the target tracking object. Used to indicate the first The measured distance matched by the historical echo distance unit measured for the target tracking object in each received signal frame. Used to represent the receiver motion acceleration of the radar receiver 11 Used to represent the object motion acceleration of the target being tracked. The range resolution unit is used to represent the radar receiver 11.

[0083] Therefore, in essence, the radar receiver 11 will detect in real time whether the frame start time of each signal receiving frame is synchronized with the time of the illumination source transmitter 12 during the target object tracking period and target object search period of any radar ranging cycle, so as to select an appropriate object tracking point correlation threshold requirement inequality to determine whether the corresponding signal receiving frame has lost the target tracking object.

[0084] Step S220: When it is detected that the frame start time of the current signal receiving frame is not synchronized with the time of the illumination source transmitter, the actual straight wave detection gate of the current signal receiving frame is determined according to the historical straight wave distance unit measured for the illumination source transmitter in the previous signal receiving frame.

[0085] In this embodiment, for a single radar ranging cycle, regardless of whether the current signal receiving frame is in the target object tracking period or the target object search period, as long as the frame start time of the current signal receiving frame is not synchronized with the time of the illumination source transmitter 12, the radar receiver 11 can construct the actual straight wave detection gate size of the current signal receiving frame to be larger than the historical straight wave detection gate size of the previous signal receiving frame by executing step S220. This is to introduce the straight wave range cell offset caused by the time asynchrony error into the subsequent straight wave signal filtering ranging process, so as to realize the actual straight wave range cell of the current signal receiving frame in the straight wave range-Doppler spectrum (i.e., the distance cell where the peak value of the straight wave range-Doppler spectrum of the current signal receiving frame is located). The center of the actual straight wave detection gate of the current signal receiving frame is the historical straight wave range cell measured by the previous signal receiving frame against the illumination source transmitter 12.

[0086] Based on this, you can refer to Figure 3 , Figure 3 yes Figure 2 The flowchart of step S220 includes the sub-steps. In this embodiment, step S220 may include sub-steps S221 to S223 to construct a straight-wave detection gate that takes into account the influence of straight-wave range cell offset for the current signal reception frame that is not synchronized in time.

[0087] Sub-step S221: The historical straight wave distance unit is directly used as the gate center of the actual straight wave detection gate.

[0088] The actual straight wave detection gate center of the current signal receiving frame is the historical straight wave distance unit measured by the previous signal receiving frame for the illumination source transmitter 12.

[0089] Sub-step S222: Calculate the expected gate widening of the actual straight wave detection gate relative to the historical straight wave detection gate of the previous signal reception frame.

[0090] In this embodiment, the influence of the straight-wave range cell offset caused by the time asynchrony error can be estimated, and the estimated straight-wave range cell offset can be directly used as the expected gate widening amount of the current signal reception frame relative to the previous signal reception frame; alternatively, a larger gate widening amount can be preset and directly used as the expected gate widening amount of the current signal reception frame relative to the previous signal reception frame; furthermore, the motion displacement of the radar receiver 11 between the current and previous signal reception frames can be estimated based on the radar receiver 11's own motion acceleration, and then the expected gate widening amount of the current signal reception frame relative to the previous signal reception frame can be determined based on this motion displacement amount. This application does not limit the specific calculation method of the expected gate widening amount.

[0091] Optionally, in one embodiment of this example, the step of calculating the expected gate widening of the actual straight-wave detection gate relative to the historical straight-wave detection gate of the previous signal reception frame may include:

[0092] According to the receiver motion acceleration of the radar receiver 11 (i.e. ), and the frame start time interval between two adjacent signal reception frames (i.e. ), calculate the first uniformly accelerated displacement of the radar receiver 11 corresponding to the frame start time interval (i.e. );

[0093] Half of the first uniformly accelerated displacement is taken as the expected gate widening of the actual straight-wave detection gate (i.e. ).

[0094] Sub-step S223: The historical straight wave detection gate size of the previous signal reception frame is enlarged according to the desired gate widening amount to obtain the actual straight wave detection gate size.

[0095] The actual straight wave detection gate size of the current signal reception frame is obtained by adding the historical straight wave detection gate size of the previous signal reception frame to the desired gate widening amount.

[0096] Therefore, by executing the above sub-steps S221 to S223, this application can construct a straight-wave detection gate that can take into account the influence of straight-wave distance cell offset for the current signal receiving frame that is not synchronized in time.

[0097] Step S230: Perform signal selection Doppler ranging processing on the straight wave signal involved in the current signal receiving frame according to the actual straight wave detection gate to obtain the actual straight wave distance unit of the current signal receiving frame relative to the illumination source transmitter.

[0098] In this embodiment, after the radar receiver 11 determines the actual straight wave detection gate of the current signal reception frame, it can filter the straight wave signals involved in the current signal reception frame based on the actual straight wave detection gate to select straight wave signals within the range of the actual straight wave detection gate. Then, the filtered straight wave signals are sequentially subjected to digital orthogonal downconversion processing, signal pulse compression processing, signal calibration processing, signal coherent accumulation processing, and moving target detection processing based on the RD (range-Doppler) spectrum to obtain a straight wave range-Doppler spectrum that takes into account the influence of straight wave range cell offset caused by time asynchrony error. Then, by performing constant false alarm detection on the straight wave range-Doppler spectrum, the actual straight wave range cell of the current signal reception frame for the illumination source transmitter 12 is obtained.

[0099] Step S240: Determine the actual echo detection gate of the current signal receiving frame based on the historical straight wave distance unit, the actual straight wave distance unit, the historical echo distance unit measured for the target tracking object in the previous signal receiving frame, and the number of frame intervals between the current signal receiving frame and the closest historical valid receiving frame.

[0100] In this embodiment, when the current signal received frame is within a target object tracking period, and the frame start time of the current signal received frame is not synchronized with the time of the illumination source transmitter 12, the radar receiver 11, during the echo detection gate construction process for the current signal received frame, considers the dual effects of the straight wave range cell offset and the echo range cell offset. Based on the historical echo range cell of the previous signal received frame, it superimposes the actual range cell offset between the actual straight wave range cell of the current signal received frame and the historical straight wave range cell of the previous signal received frame to obtain the actual echo detection gate center of the current signal received frame. Then, it considers the current signal received frame and the closest historical effective... The number of frame intervals between received frames (i.e., the valid received frame that best matches the object tracking point association threshold requirement and is closest to the current received signal frame) (which is a non-negative integer (including 0)) is used to roughly estimate the size of the echo distance cell offset caused by the object loss phenomenon. Based on the estimated offset impact range, the actual echo detection gate size of the current received signal frame is determined. This ensures that the corresponding actual echo detection gate can introduce the echo distance cell offset caused by the time asynchrony error into the subsequent echo signal filtering and ranging process, so as to realize the actual echo distance cell of the current received signal frame in the echo distance-Doppler spectrum (i.e., the distance cell where the peak of the echo distance-Doppler spectrum of the current received signal frame is located).

[0101] Alternatively, please refer to Figure 4 , Figure 4 yes Figure 2 The flowchart of step S240 includes the sub-steps. In the embodiments of this application, step S240 may include sub-steps S241 to S244, which construct an echo detection gate that can take into account the influence of echo range cell offset for the current signal reception frame that is out of time during the target object tracking period.

[0102] Sub-step S241: Calculate the distance cell difference between the actual straight wave distance cell and the historical straight wave distance cell, and perform an addition operation on the historical echo distance cell and the distance cell difference to obtain the gate center of the actual echo detection gate.

[0103] Sub-step S242: Calculate the total interval between the current signal receiving frame and the historical valid receiving frames based on the number of frame intervals and the frame start time interval between two adjacent signal receiving frames.

[0104] The number of frame intervals can be expressed as " The frame start time interval is represented as "". The total interval duration (which can be expressed as "") is then represented as "". (This is expressed using the formula "") "Calculated."

[0105] Sub-step S243: Calculate the second uniformly accelerated displacement of the target object corresponding to the total interval time based on the object motion acceleration of the target object and the total interval time.

[0106] The object's motion acceleration is expressed as " If expressed as "", then the second uniformly accelerated displacement is represented by "". "Calculated."

[0107] Sub-step S244: Use half the value of the second uniformly accelerated displacement as the gate size of the actual echo detection gate.

[0108] Therefore, by executing the above sub-steps S241 to S244, this application can construct an echo detection gate that can take into account the influence of echo range cell offset for the current signal receiving frame that is out of sync during the target object tracking period.

[0109] Furthermore, it is understood that when the current signal receiving frame is within a target object search period, and the frame start time of the current signal receiving frame is not synchronized with the time of the illumination source transmitter 12, the historical echo range unit and historical straight wave range unit of the previous signal receiving frame are often not relevant. In this case, the radar receiver 11 can directly superimpose the estimated distance unit between the radar receiver 11 and the target tracking object on the basis of the actual straight wave range unit of the current signal receiving frame to obtain the actual echo detection gate center of the current signal receiving frame. Then, referring to the above sub-steps S242 to S244, the actual echo detection gate size of the current signal receiving frame is determined to ensure that the echo range unit offset caused by the time asynchrony error can also be introduced into the subsequent echo signal screening and ranging process to realize the actual echo range unit of the current signal receiving frame in the echo range-Doppler spectrum.

[0110] Step S250: Perform signal selective Doppler ranging processing on the echo signals involved in the current signal receiving frame according to the actual echo detection gate to obtain the actual echo distance unit of the current signal receiving frame for the target tracking object.

[0111] In this embodiment, after the radar receiver 11 determines the actual echo detection gate of the current signal reception frame, it can filter the echo signals involved in the current signal reception frame based on the actual echo detection gate to select echo signals within the range of the actual echo detection gate. Then, the selected echo signals are sequentially processed by digital orthogonal downconversion, signal pulse compression, signal calibration, signal coherent accumulation, and moving target detection based on RD spectrum to obtain the echo range-Doppler spectrum considering the influence of echo range cell offset caused by time asynchrony error. Then, by performing constant false alarm rate detection on the echo range-Doppler spectrum, the actual straight-wave range cell of the current signal reception frame for the target tracking object is obtained. At this time, the radar receiver 11 can accurately measure the actual distance between the radar receiver 11 and the target object being tracked (i.e., the measured distance matching the actual echo distance unit of the current signal receiving frame) by calculating the actual distance difference between the actual straight wave distance unit and the actual echo distance unit corresponding to the current signal receiving frame. Then, the radar receiver 11 will call the object tracking point association threshold requirement inequality matching the time asynchrony state to determine whether the current signal receiving frame has lost track of the target object, that is, to determine whether the current signal receiving frame can be used as a valid tracking receiving frame.

[0112] In one embodiment of this invention, to reduce the noise floor increase caused by straight wave leakage, the radar receiver 11 can employ an adaptive filtering method. Using the straight wave signal detected by the straight wave receiving link as a reference signal, the adaptive filter weights are updated online iteratively using the LMS (Least Mean Squares) algorithm to dynamically track the characteristics of the straight wave leakage signal, generate an estimate of the straight wave leakage signal in real time, and cancel the straight wave leakage signal at the echo receiving link, thereby effectively eliminating straight wave interference in the echo receiving link.

[0113] Therefore, by executing the above steps S210 to S250, when the radar receiver 11 and the illumination source transmitter 12 are out of sync, this application can configure a reasonable receiving signal detection gate (including a straight wave detection gate and an echo detection gate) for the radar receiver 11. This allows the corresponding receiving signal detection gate to effectively incorporate the range cell offset caused by the time asynchrony error into the moving target detection process for the target tracking object, ensuring that the final ranging result has sufficient stability and accuracy, and avoiding inter-frame offset in the range dimension.

[0114] Optionally, in this application, to ensure that the radar receiver 11 can reliably perform moving target detection operations on the target tracking object while being time-synchronized with the illumination source transmitter 12, and to ensure that the final ranging result has sufficiently strong stability and accuracy, embodiments of this application... Figure 2 Based on the semi-active radar ranging method shown, another semi-active radar ranging method is provided to achieve the aforementioned objective. The following is a detailed description of this semi-active radar ranging method provided in this application.

[0115] Please refer to Figure 5 , Figure 5 This is the second schematic flowchart of the semi-active radar ranging method provided in this application embodiment. In this application embodiment, with Figure 2 Compared to the semi-active radar ranging method shown, Figure 5 The semi-active radar ranging method shown may also include steps S260 to S290.

[0116] Step S260: When it is detected that the frame start time of the current signal receiving frame is synchronized with the time of the illumination source transmitter, the historical straight wave distance unit of the previous signal receiving frame is used as the gate center of the actual straight wave detection gate, and the gate size of the actual straight wave detection gate is configured according to the preset straight wave gate size.

[0117] In this embodiment, for a single radar ranging cycle, regardless of whether the current signal receiving frame is in the target object tracking period or the target object search period, as long as the frame start time of the current signal receiving frame is synchronized with the time of the illumination source transmitter 12, the radar receiver 11 can set the actual straight wave detection gate size of the current signal receiving frame to a preset straight wave gate size by executing step S260, so as to improve ranging accuracy in subsequent straight wave signal filtering ranging processes. The center of the actual straight wave detection gate of the current signal receiving frame is the historical straight wave distance unit measured against the illumination source transmitter 12 in the previous signal receiving frame.

[0118] Step S270: Perform signal selection Doppler ranging processing on the straight wave signal involved in the current signal receiving frame according to the actual straight wave detection gate to obtain the actual straight wave distance unit of the current signal receiving frame relative to the illumination source transmitter.

[0119] In this embodiment, the specific execution process of step S270 can be referred to the detailed description of step S230 above, and will not be repeated here.

[0120] Step S280: Determine the actual echo detection gate of the current signal receiving frame based on the historical echo distance unit of the previous signal receiving frame and the number of frame intervals between the current signal receiving frame and the closest historical valid receiving frame.

[0121] In this embodiment, when the current signal received frame is within a target object tracking period, and the frame start time of the current signal received frame is synchronized with the time of the illumination source transmitter 12, the radar receiver 11, during the construction of the echo detection gate for the current signal received frame, can directly use the historical echo distance unit of the previous signal received frame as the actual echo detection gate center of the current signal received frame. Then, considering the number of frame intervals between the current signal received frame and the closest historical valid received frame, it can roughly estimate the size of the echo distance unit offset caused by the object loss phenomenon, and determine the size of the actual echo detection gate for the current signal received frame based on the estimated offset impact range. This ensures that the corresponding actual echo detection gate can improve the ranging accuracy in the subsequent echo signal filtering and ranging process.

[0122] Alternatively, please refer to Figure 6 , Figure 6 yes Figure 5 The flowchart of step S280 includes the sub-steps. In the embodiments of this application, step S280 may include sub-steps S281 to S284 to construct a suitable echo detection gate for the current signal reception frame that is time-synchronized during the target object tracking period.

[0123] Sub-step S281: The historical echo distance unit is directly used as the gate center of the actual echo detection gate.

[0124] Sub-step S282: Calculate the total interval between the current signal receiving frame and the historical valid receiving frames based on the number of frame intervals and the frame start time interval between two adjacent signal receiving frames.

[0125] Sub-step S283: Calculate the second uniformly accelerated displacement of the target object corresponding to the total interval time based on the object motion acceleration of the target object and the total interval time.

[0126] Sub-step S284: Use half the value of the second uniformly accelerated displacement as the gate size of the actual echo detection gate.

[0127] In this embodiment, the specific execution process of each of the above sub-steps S282 to S284 can be referred to the detailed description of the above sub-steps S242 to S244 above, and will not be repeated here.

[0128] Therefore, this application can construct a suitable echo detection gate for the current signal receiving frame that is time-synchronized during the target object tracking period by executing the above sub-steps S281 to S284.

[0129] Furthermore, it is understood that when the current signal reception frame is within a target object search period, and the frame start time of the current signal reception frame is synchronized with the time of the illumination source transmitter 12, the historical echo distance unit and historical straight wave distance unit of the previous signal reception frame are often not relevant. In this case, the radar receiver 11 can directly superimpose the estimated distance unit between the radar receiver 11 and the target tracking object on the basis of the actual straight wave distance unit of the current signal reception frame to obtain the actual echo detection gate center of the current signal reception frame. Then, referring to the above sub-steps S282 to S284, the actual echo detection gate size of the current signal reception frame is determined to ensure that the corresponding actual echo detection gate can improve the ranging accuracy in the subsequent echo signal filtering ranging process.

[0130] Step S290: Perform signal selective Doppler ranging processing on the echo signals involved in the current signal receiving frame according to the actual echo detection gate to obtain the actual echo distance unit of the current signal receiving frame for the target tracking object.

[0131] In this embodiment, the specific execution process of step S290 can be referred to the detailed description of step S250 above, and will not be repeated here.

[0132] Therefore, by executing the above steps S260 to S290, the radar receiver 11 can perform reliable moving target detection operation for the target tracking object while being time-synchronized with the illumination source transmitter 12, ensuring that the final ranging result has sufficient stability and accuracy.

[0133] Optionally, in this application, to ensure that the radar receiver 11 can automatically calibrate and compensate the receiving channel parameters of the echo and difference channels involved in the echo receiving link during the illumination source rest period of any radar ranging cycle, and to ensure that the echo receiving data of each of the three channels can maintain consistency on the time axis, this embodiment of the application... Figure 2 or Figure 5 Based on the semi-active radar ranging method shown, another semi-active radar ranging method is provided to achieve the aforementioned objective. The following is a detailed description of this semi-active radar ranging method provided in this application.

[0134] Please refer to Figure 7 , Figure 7 This is the third schematic flowchart of the semi-active radar ranging method provided in this application embodiment. In this application embodiment, with Figure 2 or Figure 5 Compared to the semi-active radar ranging method shown, Figure 7 The semi-active radar ranging method shown may also include steps S310 to S340.

[0135] Step S310: During the illumination source rest period of any radar ranging cycle, generate an RF calibration signal with an equivalent distance of zero, and acquire the coupled echo calibration signals obtained by the antenna and differential converters of the three channels of echo and differential respectively for coupling the RF calibration signal.

[0136] In this embodiment, the main control unit in the radar receiver 11 can generate a linear frequency modulated pulse signal with an equivalent distance of zero during the illumination source rest period of any radar ranging cycle, as the baseband calibration signal for the illumination source rest period, and call the intermediate frequency channel chip to perform digital up-conversion processing on the baseband calibration signal to obtain the corresponding radio frequency calibration signal. Then, the main control unit will couple the radio frequency calibration signal to the echo and difference channels of the echo receiving link through the antenna and difference converter to obtain the coupled echo calibration signal sensed by each of the echo and difference channels.

[0137] Step S320: Based on the RF calibration signal, the coupled echo calibration signals of the echo and differential channels are sequentially subjected to digital quadrature downconversion and signal pulse compression processing to obtain the zero-pitch mapping calibration signals of the echo and differential channels respectively.

[0138] In this embodiment, to avoid the problem of significant sidelobe rise after signal pulse compression due to zero-frequency leakage in the echo receiving link, the center frequencies of the three coupled echo calibration signals can be shifted by adjusting the local oscillator frequency of the RF receiving chip in the echo receiving link to move away from the zero-frequency leakage phenomenon. Then, the three coupled echo calibration signals are subjected to digital quadrature down-conversion processing to obtain three zero-IF echo calibration signals. Next, the three zero-IF echo calibration signals are low-pass filtered to remove the zero-frequency leakage signal. At this point, the signal pulse compression processing of the echo and difference channels can be completed by multiplying the matched filter conjugate template corresponding to the baseband calibration signal with a Hamming window, and then convolving it with the ADC sampling data of the three low-pass filtered zero-IF echo calibration signals. This yields the zero-distance mapping calibration signals for each of the echo and difference channels.

[0139] Step S330: Detect whether the actual distance cells of the echo and differential channels at the points of maximum signal amplitude of the corresponding zero-distance mapping calibration signals are consistent.

[0140] In this embodiment, when the actual distance units of the echo and differential channels at the point of maximum signal amplitude are not consistent, it indicates that the receiving channel parameters of the echo and differential channels are not consistent, and step S340 needs to be executed. When the actual distance units of the echo and differential channels at the point of maximum signal amplitude are consistent, it indicates that the receiving channel parameters of the echo and differential channels are consistent, and the echo received data of the sum and differential channels can maintain consistency on the time axis.

[0141] Step S340: When the actual distance cells of the echo and differential channels at the points of maximum signal amplitude are detected to be inconsistent, the difference between the azimuth difference channel and the elevation difference channel in the echo and differential channels and the actual calibration signal difference between the azimuth difference channel and the elevation difference channel and the beam channel is calculated. The receiving channel parameters of the azimuth difference channel and the elevation difference channel are compensated according to the calculated actual calibration signal difference, so that the receiving channel parameters of the echo and differential channels are kept consistent.

[0142] The actual calibration signal difference includes signal delay error and signal amplitude and phase error.

[0143] Therefore, by executing the above steps S310 to S340, the radar receiver 11 can automatically calibrate and compensate the receiving channel parameters of the echo and difference channels involved in the echo receiving link during the illumination source rest period of any radar ranging cycle, ensuring that the echo receiving data of each of the three channels can maintain consistency on the time axis.

[0144] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0145] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A semi-active radar ranging method, characterized in that, The ranging method is applied to a radar receiver included in a semi-active radar system, wherein the semi-active radar system further includes an illumination source transmitter, and the ranging method includes: During the target tracking period of any radar ranging cycle, it can detect in real time whether it is synchronized with the time of the illumination source transmitter. When it is detected that the frame start time of the current signal receiving frame is not synchronized with the time of the illumination source transmitter, the actual straight wave detection gate of the current signal receiving frame is determined according to the historical straight wave distance unit measured for the illumination source transmitter in the previous signal receiving frame, wherein the actual straight wave detection gate size of the current signal receiving frame is greater than the historical straight wave detection gate size of the previous signal receiving frame. According to the actual straight wave detection gate, the straight wave signal involved in the current signal reception frame is subjected to signal selection Doppler ranging processing to obtain the actual straight wave distance unit of the current signal reception frame relative to the illumination source transmitter. Based on the historical straight wave distance unit, the actual straight wave distance unit, and the historical echo distance unit measured for the target tracking object in the previous signal reception frame, as well as the number of frame intervals between the current signal reception frame and the closest historical valid reception frame, the actual echo detection gate of the current signal reception frame is determined, wherein the measured distance of the historical valid reception frame for the target tracking object meets the object tracking point association threshold requirement. According to the actual echo detection gate, the echo signal involved in the current signal reception frame is processed by signal selective Doppler ranging to obtain the actual echo distance unit of the current signal reception frame for the target tracking object; The step of determining the actual straight-wave detection gate of the current signal reception frame based on the historical straight-wave distance unit measured for the illumination source transmitter in the previous signal reception frame includes: The historical straight wave distance unit is directly used as the gate center of the actual straight wave detection gate; Calculate the expected gate widening of the actual straight-wave detection gate relative to the historical straight-wave detection gate of the previous signal reception frame; wherein, based on the receiver motion acceleration of the radar receiver and the frame start time interval between two adjacent signal reception frames, calculate the first uniformly accelerated displacement of the radar receiver corresponding to the frame start time interval, and then take half of the first uniformly accelerated displacement as the expected gate widening of the actual straight-wave detection gate. The historical straight wave detection gate size of the previous signal reception frame is enlarged according to the desired gate widening amount to obtain the actual straight wave detection gate size.

2. The ranging method according to claim 1, characterized in that, The step of determining the actual echo detection gate of the current signal receiving frame based on the historical straight-wave distance unit, the actual straight-wave distance unit, the historical echo distance unit measured for the target tracking object in the previous signal receiving frame, and the number of frame intervals between the current signal receiving frame and the nearest historical valid receiving frame includes: Calculate the distance cell difference between the actual straight wave distance cell and the historical straight wave distance cell, and perform an addition operation on the historical echo distance cell and the distance cell difference to obtain the gate center of the actual echo detection gate; Based on the number of frame intervals and the frame start time interval between two adjacent signal received frames, calculate the total interval between the current signal received frame and the historical valid received frames; Based on the object motion acceleration of the target tracking object and the total interval duration, calculate the second uniformly accelerated displacement of the target tracking object corresponding to the total interval duration; Half of the second uniformly accelerated displacement is used as the gate size of the actual echo detection gate.

3. The ranging method according to claim 1, characterized in that, For the first time in a single radar ranging cycle For each received signal frame, when the frame start time is not synchronized with the time of the illumination source transmitter, the object tracking point association threshold requirement corresponding to the received signal frame is expressed by the following inequality: ； in, Used to indicate the duration of the frame start time interval between two adjacent received signal frames. Used to indicate the first The measured distance matched by each signal received frame to the actual echo distance unit measured for the target tracking object. Used to indicate the first The measured distance matched by the historical echo distance unit measured for the target tracking object in each received signal frame. Used to indicate the first Each received signal frame corresponds to the transceiver distance matched to the actual straight-wave distance unit measured by the transmitter of the illumination source. Used to indicate the first Each received signal frame matches the transceiver distance to the historical straight-wave distance unit measured by the transmitter of the illumination source. Used to represent the receiver motion acceleration of the radar receiver. Used to represent the object motion acceleration of the target being tracked. The range resolution unit is used to represent the radar receiver.

4. The ranging method according to claim 1, characterized in that, For the first time in a single radar ranging cycle For each received signal frame, when the frame start time of the received signal frame is synchronized with the time of the illumination source transmitter, the object tracking point association threshold requirement corresponding to the received signal frame is expressed by the following inequality: ； in, Used to indicate the duration of the frame start time interval between two adjacent received signal frames. Used to indicate the first The measured distance matched by each signal received frame to the actual echo distance unit measured for the target tracking object. Used to indicate the first The measured distance matched by the historical echo distance unit measured for the target tracking object in each received signal frame. Used to represent the receiver motion acceleration of the radar receiver. Used to represent the object motion acceleration of the target being tracked. The range resolution unit is used to represent the radar receiver.

5. The ranging method according to any one of claims 1-4, characterized in that, The ranging method further includes: When the frame start time of the current signal reception frame is detected to be synchronized with the time of the illumination source transmitter, the historical straight wave distance unit of the previous signal reception frame is used as the gate center of the actual straight wave detection gate, and the gate size of the actual straight wave detection gate is configured according to the preset straight wave gate size. According to the actual straight wave detection gate, the straight wave signal involved in the current signal reception frame is subjected to signal selection Doppler ranging processing to obtain the actual straight wave distance unit of the current signal reception frame relative to the illumination source transmitter. The actual echo detection gate of the current signal receiving frame is determined based on the historical echo distance unit of the previous signal receiving frame and the number of frame intervals between the current signal receiving frame and the nearest valid historical receiving frame. According to the actual echo detection gate, signal selective Doppler ranging processing is performed on the echo signal involved in the current signal reception frame to obtain the actual echo distance unit of the current signal reception frame for the target tracking object.

6. The ranging method according to claim 5, characterized in that, The step of determining the actual echo detection gate of the current signal receiving frame based on the historical echo distance unit of the previous signal receiving frame and the number of frame intervals between the current signal receiving frame and the nearest historical valid receiving frame includes: The historical echo distance unit is directly used as the gate center of the actual echo detection gate; Based on the number of frame intervals and the frame start time interval between two adjacent signal received frames, calculate the total interval between the current signal received frame and the historical valid received frames; Based on the object motion acceleration of the target tracking object and the total interval duration, calculate the second uniformly accelerated displacement of the target tracking object corresponding to the total interval duration; Half of the second uniformly accelerated displacement is used as the gate size of the actual echo detection gate.

7. The ranging method according to any one of claims 1-4, characterized in that, The ranging method further includes: During the illumination source rest period of any radar ranging cycle, an equivalent distance of zero radio frequency calibration signal is generated, and coupled echo calibration signals are obtained by coupling the radio frequency calibration signal through the antenna and differential converter of the three channels of echo and difference. Based on the radio frequency calibration signal, the coupled echo calibration signals of the echo and differential channels are sequentially subjected to digital quadrature downconversion and signal pulse compression processing to obtain the zero-pitch mapping calibration signals of the echo and differential channels respectively. Detect whether the actual distance cells of the echo and differential three channels are consistent at the point of maximum signal amplitude of the corresponding zero-distance mapping calibration signal; If the actual distance units at the maximum signal amplitude points of the echo and differential channels are not consistent, the difference between the azimuth and elevation difference channels and the actual calibration signal of the beam channel is calculated relative to the actual calibration signal of the beam channel. The receiving channel parameters of the azimuth and elevation difference channels are compensated according to the calculated actual calibration signal differences to keep the receiving channel parameters of the echo and differential channels consistent.

8. A semi-active radar system, characterized in that, The radar system includes a radar receiver and an illumination source transmitter, wherein the illumination source transmitter is used to transmit electromagnetic waves toward the target being tracked; the radar receiver is used to receive the direct wave signal emitted from the illumination source transmitter and to receive the echo signal reflected by the target being tracked. The radar receiver stores a computer program and can execute the computer program to implement the semi-active radar ranging method according to any one of claims 1-7.

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