Harmonic radar-based maritime search and rescue target detection method, device and equipment

Abstract

Embodiments of the present disclosure disclose a harmonic radar-based maritime search and rescue target detection method, device and equipment. A specific embodiment of the method comprises: generating a plurality of transmitting excitation signals through a signal processing board and a first waveband receiving and transmitting module; performing electronic beam scanning on a target sea surface area according to an antenna module, the first waveband receiving and transmitting module and the plurality of transmitting excitation signals; performing waveband front-end processing on a second waveband echo signal to generate four polarized monopulse channel signals; performing frequency domain polarization feature extraction on the four polarized monopulse channel signals to generate a signal frequency domain polarization feature set; and performing adaptive target detection on the signal frequency domain polarization feature set to generate a search and rescue target detection result. The embodiment adopts an S / C harmonic radar and a dual-polarized phased array structure, generates a receivable harmonic echo from a search and rescue target, thereby suppressing sea clutter energy in two physical dimensions of frequency band and polarization, and further realizing stable detection of the search and rescue target.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the field of computer technology, and more specifically to a method, apparatus, and equipment for detecting maritime search and rescue targets based on harmonic radar. Background Technology

[0002] In maritime search and rescue scenarios, rapid and reliable detection of small targets such as people in the water and life rafts is often required. Currently, when detecting maritime search and rescue targets, sea surface monitoring radar based on co-frequency reflection is commonly used for echo detection to determine the approximate location of the target. However, in complex sea conditions, the sea surface generates strong linearly scattered echoes from the radar's electromagnetic waves. These echoes have energy far exceeding that of the radar-scattered echoes from small targets such as people in the water or life rafts. This causes the target echoes to be submerged by sea clutter at the receiving end, making it difficult for traditional co-frequency reflection-based radar to physically distinguish the target from the sea surface background. Consequently, it becomes difficult to reliably detect search and rescue targets with extremely small radar cross-sections. Summary of the Invention

[0003] The summary portion of this disclosure is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description portion. This summary portion is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0004] Some embodiments of this disclosure propose a method, apparatus, electronic device, and computer-readable medium for detecting maritime search and rescue targets based on harmonic radar to address the technical problems mentioned in the background section above.

[0005] In a first aspect, some embodiments of this disclosure provide a method for detecting maritime search and rescue targets based on harmonic radar. The method includes: generating multiple transmission excitation signals using a signal processing board and a first-band transceiver module included in a harmonic radar device, wherein the harmonic radar device further includes an antenna module and a second-band transceiver module; performing electronic beam scanning on a target sea surface area based on the antenna module, the first-band transceiver module, and the generated multiple transmission excitation signals, wherein the target sea surface area is a sea surface area where target search and rescue is underway; and responding to the antenna module receiving a second-band echo signal, performing electronic beam scanning on the target sea surface area based on the second-band transceiver module. The band transceiver module performs band front-end processing on the received second-band echo signal to generate four polarized single-pulse channel signals. The second-band echo signal is transmitted after the cooperative tag installed on the search and rescue target has multiplied the frequency of the received first-band signal. Based on the multi-dimensional signal parameters corresponding to the multiple transmission excitation signals and the second-band echo signal, the module extracts frequency-domain polarization features from the four polarized single-pulse channel signals to generate a signal frequency-domain polarization feature set. Using a pre-constructed target detector, the module performs adaptive target detection on the signal frequency-domain polarization feature set to generate search and rescue target detection results.

[0006] Secondly, some embodiments of this disclosure provide a maritime search and rescue target detection device based on harmonic radar. The device includes: a generation unit configured to generate multiple transmission excitation signals via a signal processing board and a first-band transceiver module included in the harmonic radar equipment, wherein the harmonic radar equipment further includes: an antenna module and a second-band transceiver module; a scanning unit configured to perform electronic beam scanning of a target sea surface area based on the antenna module, the first-band transceiver module, and the generated multiple transmission excitation signals, wherein the target sea surface area is a sea surface area where target search and rescue is underway; and a band front-end processing unit configured to, in response to the antenna module receiving a second-band echo signal, process... The aforementioned second-band transceiver module performs band front-end processing on the received second-band echo signal to generate four-channel polarized monopulse signals. The second-band echo signal is transmitted after the received first-band signal is frequency-multiplied by a cooperative tag installed on the search and rescue target. The feature extraction unit is configured to extract frequency-domain polarization features from the four-channel polarized monopulse signals based on the multi-dimensional signal parameters corresponding to the multiple transmission excitation signals and the second-band echo signal, generating a signal frequency-domain polarization feature set. The target detection unit is configured to perform adaptive target detection on the signal frequency-domain polarization feature set based on a pre-constructed target detector, generating a search and rescue target detection result.

[0007] Thirdly, some embodiments of this disclosure provide an electronic device, including: one or more processors; and a storage device having one or more programs stored thereon, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method described in any implementation of the first aspect above.

[0008] Fourthly, some embodiments of this disclosure provide a computer-readable medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the method described in any of the implementations of the first aspect above.

[0009] The various embodiments of this disclosure have the following beneficial effects: The maritime search and rescue target detection method based on harmonic radar in some embodiments of this disclosure adopts S / C harmonic radar and a dual-polarization phased array structure. By enabling the search and rescue target to generate an acceptable harmonic echo, sea clutter energy is suppressed in both the frequency band and polarization physical dimensions, thereby achieving stable detection of the search and rescue target. Specifically, the reason for the poor stability of the related search and rescue target detection is that, under complex sea conditions, the sea surface will generate strong linear scattering echoes of the electromagnetic waves emitted by the radar. The energy of these echoes is much higher than the radar scattering echoes of small search and rescue targets such as people in the water or life-saving devices. This causes the target echoes to be submerged by sea clutter at the receiving end, making it difficult for traditional radar based on co-frequency reflection to physically distinguish the target from the sea surface background, thus making it difficult to stably detect search and rescue targets with extremely small radar cross-sections. Based on this, some embodiments of the maritime search and rescue target detection method based on harmonic radar disclosed herein firstly generate multiple transmission excitation signals through a signal processing board and a first-band transceiver module included in the harmonic radar equipment. The harmonic radar equipment further includes an antenna module and a second-band transceiver module. Thus, by uniformly generating and controlling the multiple transmission excitation signals through the signal processing board, the first-band transmission link maintains stable signal detection during the scanning of the target sea surface area. Then, based on the antenna module, the first-band transceiver module, and the generated multiple transmission excitation signals, an electronic beam scan is performed on the target sea surface area, where the target sea surface area is the area where target search and rescue is underway. Therefore, by cooperating with the antenna module and the first-band transceiver module, the transmitted signals can be sequentially irradiated onto the target sea surface area with beams of different directions, allowing the transmitted signals to detect the sea surface in sections according to direction, avoiding spatial overlap of echoes, thereby improving signal detection stability. Subsequently, in response to the antenna module receiving the second-band echo signal, the second-band transceiver module performs band front-end processing on the received second-band echo signal to generate four polarized monopulse channel signals. The second-band echo signal is transmitted by a cooperative tag installed on the search and rescue target after frequency doubling the received first-band signal. Thus, the second-band transceiver module can receive the frequency-doubled echo generated by the cooperative tag and decompose it into multiple polarized monopulse channels, enabling the search and rescue target to form an observable echo signal in the second band. Since sea clutter and floating objects do not generate frequency-doubled echoes and are significantly suppressed, the echo signal between the search and rescue target and the sea surface background clutter can be significantly distinguished at the receiving end. Next, based on the multi-dimensional signal parameters corresponding to the multiple transmitted excitation signals and the second-band echo signal, frequency domain polarization features are extracted from the four polarized monopulse channel signals to generate a signal frequency domain polarization feature set.Therefore, by performing spectral analysis on the four echo signals within the harmonic band and extracting features based on changes in polarization direction, the search and rescue targets carrying cooperative tags differ from sea clutter in frequency distribution and polarization behavior. This transforms the originally highly fluctuating echo signals into more stable and easily discriminable feature vectors. Finally, based on a pre-constructed target detector, adaptive target detection is performed on the aforementioned signal frequency domain polarization feature set to generate search and rescue target detection results. Thus, an adaptive threshold target detector can be used to monitor the signal frequency domain polarization feature set, automatically adjusting the discrimination criteria according to the strength and local changes of sea clutter. This maintains a low false alarm rate under different sea states while improving the detection capability of weak search and rescue targets, thereby achieving stable detection of search and rescue targets. Attached Figure Description

[0010] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0011] Figure 1 This is a flowchart of some embodiments of the maritime search and rescue target detection method based on harmonic radar according to the present disclosure;

[0012] Figure 2 This is a schematic diagram of the radar signal flow of the maritime search and rescue target detection method based on harmonic radar disclosed herein;

[0013] Figure 3 This is a schematic diagram of the principle of the antenna unit final stage of the first-band transceiver module disclosed herein;

[0014] Figure 4 This is a schematic diagram of the principle of the first band transmission excitation module included in the first band transmission and reception module disclosed herein;

[0015] Figure 5 This is a schematic diagram of the principle of the first band receiving module included in the first band transmitting and receiving module disclosed herein;

[0016] Figure 6 This is a schematic diagram of the antenna module layout of the harmonic radar device disclosed herein;

[0017] Figure 7 This is a schematic diagram of the front and back sides of the phased array antenna PCB of the antenna module disclosed herein;

[0018] Figure 8 This is a schematic diagram of the principle of the second-band pre-stage first transceiver module, which is included in the second-band transceiver module disclosed herein;

[0019] Figure 9 This is a schematic diagram of the beam channel synthesis path of the second-band pre-stage second transceiver module included in the second-band transceiver module disclosed herein;

[0020] Figure 10 This is a schematic diagram of the principle of the second-band pre-stage second transceiver module, which is included in the second-band transceiver module disclosed herein;

[0021] Figure 11 This is a schematic diagram of the structure of some embodiments of the maritime search and rescue target detection device based on harmonic radar according to the present disclosure;

[0022] Figure 12 This is a schematic diagram of the structure of an electronic device suitable for implementing some embodiments of the present disclosure. Detailed Implementation

[0023] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0024] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0025] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0026] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0027] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

[0028] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] Figure 1 illustrates a flowchart 100 of some embodiments of the maritime search and rescue target detection method based on harmonic radar according to this disclosure. The maritime search and rescue target detection method based on harmonic radar includes the following steps:

[0030] Step 101: Generate multiple transmission excitation signals using the signal processing board and the first band transceiver module included in the harmonic radar equipment.

[0031] In some embodiments, the execution entity (e.g., a computing device) of the maritime search and rescue target detection method based on harmonic radar can generate multiple transmission excitation signals through the signal processing board and the first-band transceiver module included in the harmonic radar device. The harmonic radar device further includes an antenna module and a second-band transceiver module. The harmonic radar device can be an S / C harmonic radar used for signal detection of target sea surface areas. The target sea surface area can be a sea surface area where target search and rescue is underway. The search and rescue target can be a person in the water with a cooperation tag or an object with a cooperation tag. The cooperation tag can be a passive or semi-passive nonlinear radio frequency device installed on the search and rescue target, which, after receiving an S-band signal, can perform frequency multiplication of the received S-band signal through its internal nonlinear device and radiate the corresponding frequency-multiplied C-band signal outward. The first-band transceiver module can be a module for transmitting and receiving the first band (i.e., a TR module, T / R module). The first band can be the S-band, i.e., an electromagnetic wave band with a frequency range of 2-4 GHz. The aforementioned second-band transceiver module can be used for transmitting and receiving signals in the second band. The second band can be the C-band, i.e., an electromagnetic wave band with a frequency range of 4-8 GHz. The aforementioned antenna module is an antenna system in the aforementioned harmonic radar equipment used to radiate the first-band transmit excitation signal to the target sea surface area, and to receive the second-band echo signal from the target sea surface area and introduce it into the aforementioned second-band transceiver module. The aforementioned multiple transmit excitation signals are S-band multi-channel radio frequency signals generated by the signal processing board and amplified by the aforementioned first-band transceiver module, corresponding to the input signals of multiple transmit channels in the aforementioned antenna module. In practice, firstly, the aforementioned execution entity can generate a baseband modulation sequence (e.g., a phase-coded sequence) for modulation using the aforementioned signal processing board, and output the baseband modulation sequence to the aforementioned first-band transceiver module. Then, the radio frequency synthesizer built into the aforementioned first-band transceiver module performs carrier modulation and up-conversion processing on the baseband modulation sequence to generate a first-band modulated radio frequency signal. Subsequently, the generated first-band modulated radio frequency signal is amplified by the power amplifier included in the first-band receiving and transmitting module, and then distributed into multiple transmit excitation signals by a 1-to-8 power divider.

[0032] like Figure 2 The radar signal flow shown above, and the working process of the aforementioned harmonic radar equipment are as follows: Figure 2As shown, AD stands for analog-to-digital converter. DA stands for digital-to-analog converter. STR represents S-band transmit / receive control. CTR represents C-band transmit / receive control. Tx represents signal transmission. Rx represents signal reception. First, the harmonic radar equipment drives the antenna module to transmit the S-band signal f0 through the digital-to-analog converter (DAC). Then, in the complex clutter environment at sea, the cooperative tag installed on the person in the water receives the S-band signal, multiplies it to 2f0, and reflects it back. Other objects in nature (non-search and rescue targets) can only reflect back signals in the f0 band, but the harmonic radar equipment only receives signals in the 2f0 band. Therefore, the harmonic radar equipment filters out the fundamental frequency signal reflected back by the non-cooperative tag when receiving the signal. Thus, the harmonic radar equipment can process the received signal, combine it with electronic beam scanning to achieve wide-range and rapid target search, and effectively suppress clutter interference using the spatial filtering capability of phased array technology, thereby improving the detection capability of weak search and rescue targets and ultimately achieving accurate and stable detection of cooperative targets.

[0033] It should be noted that the aforementioned computing devices can be either hardware or software. When the computing device is hardware, it can be implemented as a distributed cluster consisting of multiple servers or terminal devices, or as a single server or a single terminal device. When the computing device is software, it can be installed on the hardware devices listed above. It can be implemented as, for example, multiple software programs or software modules used to provide distributed services, or as a single software program or software module. No specific limitations are made here. It should be understood that the number of the aforementioned computing devices can be arbitrary, depending on the implementation requirements.

[0034] In some optional implementations of certain embodiments, the aforementioned execution entity can generate multiple transmission excitation signals through the signal processing board and the first band transceiver module included in the harmonic radar device via the following steps:

[0035] The first step involves generating a first-band linear frequency modulated (LFM) waveform using the aforementioned signal processing board, according to preset first-band signal parameters. The signal processing board, part of the harmonic radar equipment, is the electronic hardware used for digital signal generation, analog-to-digital and digital-to-analog conversion, and data processing. It includes a processor, memory, and interface circuitry. The preset first-band signal parameters may include, but are not limited to: signal frequency, operating frequency band, signal bandwidth, pulse width, modulation slope, pulse repetition interval (PRI), or pulse repetition frequency (PRF). In practice, the executing entity can use the signal processing board to generate a discretely sampled S-band LFM waveform sequence (which can be in I / Q form or real signal form) in the digital domain, and organize the generated waveform sequence into a pulse sequence according to the preset first-band signal parameters to obtain the first-band LFM waveform.

[0036] The second step involves performing a digital-to-analog conversion on the first-band linear frequency modulation waveform using the onboard interface of the signal processing board to generate a first-band transmission excitation signal. In practice, the executing entity can input the generated first-band linear frequency modulation waveform into the DA interface of the signal processing board to output the first-band transmission excitation signal in the form of an analog electrical signal.

[0037] The third step involves amplifying the power of the first-band transmit excitation signal using the first-band transmit excitation module included in the first-band transceiver module, thereby generating multiple transmit excitation signals. This first-band transmit excitation module can be an S-band transmit excitation module. In practice, the executing entity can amplify the power of the first-band transmit excitation signal using the first-band transmit excitation module, thereby boosting the low-power drive signal to the amplitude level required for the array channel input, and distributing the first-band transmit excitation signal into multiple channels (i.e., 8 channels) according to the number of array channels, thus obtaining multiple transmit excitation signals.

[0038] like Figure 3 The diagram illustrates the design principle of the final stage transceiver module for an antenna element. Here, SHt1 represents S-band horizontally polarized transmit channel 1, SHr1 represents S-band horizontally polarized receive channel 1, and SVr1 represents S-band vertically polarized receive channel 1. A final stage transceiver module for an antenna element (i.e., the final stage TR module, STRA module of an S-band antenna element) consists of four transmit / receive RF channels. Internally, it comprises core components such as an S-band circulator, power amplifier (PA), low-noise amplifier, transmit / receive phase shift attenuators (i.e., phase shifters and attenuators), and a power divider system, along with corresponding power supply, control, and protection peripheral circuits. The aforementioned power amplifier primarily performs final-stage amplification and transmit filtering of the transmitted RF signal, ensuring the RF signal possesses the system's required radiated power and second harmonic suppression. It mainly consists of a power amplifier, an S-band cavity filter, and corresponding matching and auxiliary circuits. The first antenna element's final-stage transceiver module (STRA) contains two arrays of dual-polarized final-stage transceivers. Four circulators connect to the two dual-polarized arrays, and eight STRA modules connect to 16 dual-polarized antenna elements. The four circulators divide the transmit and receive feed channels: one connects to a power amplifier to generate the transmit output, and the other connects to a low-noise amplifier to receive the echo. The transmit channel uses four phase shifters to control the transmit beam scanning, and the transmit excitation signal SHt1 is connected to the transmit excitation module via a four-power divider. The receive channel uses a two-power divider to synthesize horizontal polarization into SHr1, and a two-power divider to synthesize vertical polarization into SVr1.

[0039] like Figure 4The design principle of the first-band transmit excitation module is shown below, where Ht1 represents horizontally polarized transmit 1, Ht2 represents horizontally polarized transmit 2, Ht3 represents horizontally polarized transmit 3, Ht4 represents horizontally polarized transmit 4, Ht5 represents horizontally polarized transmit 5, Ht6 represents horizontally polarized transmit 6, Ht7 represents horizontally polarized transmit 7, Ht8 represents horizontally polarized transmit 8, and Bt represents transmit excitation. The transmit excitation signals in the eight STRA signals come from the first-band transmit excitation module (i.e., the S-band transmit excitation module). The aforementioned first-band transmit excitation module includes one power amplifier and one 8-way power divider. The power amplifier receives the linear frequency modulated signal generated by the DA interface of the aforementioned signal processing board.

[0040] like Figure 5 The design principle of the S-band receiver module shown is as follows: Hr represents horizontal polarization reception; Vr represents vertical polarization reception; SBH1 represents S-band horizontal polarization beam 1; SBH2 represents S-band horizontal polarization beam 2; SBV1 represents S-band vertical polarization beam 1; SBV2 represents S-band vertical polarization beam 2. The S-band receiver module receives the output signals from the eight STRA module receiving channels. The output signals SHr1, SHr2, SHr3, and SHr4 from the eight STRA modules are combined into S-band horizontal polarization beam 1, i.e., SBH1, through a 4-power divider; SHr5, SHr6, SHr7, and SHr8 are combined into S-band horizontal polarization beam 2, i.e., SBH2, through a 4-power divider; and SBVr1, SBVr2, SBVr3, and SVr4 are combined into S-band vertical polarization beam 1, i.e., SBV1, SBVr4, through a 4-power divider. SVr5, SVr6, SVr7, and SVr8 are combined into S-band horizontally polarized beam 2, namely SBV2, through a 4-power divider. Among them, SBH1 and SBH2 are sent to two AD channels of the signal processing board for S-band horizontally polarized azimuth single-pulse angle measurement, and SBV1 and SBV2 are sent to two AD channels of the signal processing board for S-band vertically polarized azimuth single-pulse angle measurement.

[0041] Step 102: Perform electronic beam scanning on the target sea surface area based on the antenna module, the first band transceiver module, and the generated multi-channel transmission excitation signals.

[0042] In some embodiments, the aforementioned execution entity can perform electronic beam scanning of the target sea surface area based on the aforementioned antenna module, the aforementioned first-band transceiver module, and the generated multiple transmission excitation signals. The target sea surface area is the sea surface area where target search and rescue is underway. In practice, firstly, the aforementioned antenna module can be pre-configured with multiple fixed transmission sub-beam channels covering different azimuth angles of the target sea surface area, each fixed transmission sub-beam channel corresponding to a preset spatial direction. Then, the aforementioned first-band transceiver module connects the multiple first-band transmission excitation signals to different transmission sub-beam channels through various radio frequency switches (e.g., multi-channel single-pole multi-throw switches). Subsequently, the aforementioned signal processing board can control the various radio frequency switches to switch between different transmission sub-beam channels according to a preset scanning sequence, thereby achieving electronic beam scanning of the target sea surface area in a discrete beam polling manner.

[0043] like Figure 6 As shown, the aforementioned harmonic radar equipment (i.e., S / C harmonic radar) includes an HV dual-polarized antenna module with a common array design. The antenna elements are arranged in a 4x16 column layout. The H-polarized feed points and V-polarized feed points of the four antenna elements in each column are combined via a power divider, supporting simultaneous or time-division multiplexing of HV transmission and reception. It possesses azimuth phase scanning and amplitude comparison measurement capabilities. The overall radar antenna consists of... Figure 6 The four radar antenna modules shown are arranged horizontally. Furthermore, to simplify the PCB stack-up of the antenna modules, the antenna reflector and the power divider reference ground plane are designed on the same layer. The antenna module consists of four layers in total. The front and back sides of the SC phased array antenna PCB are shown below. Figure 7 As shown.

[0044] In some optional implementations of certain embodiments, the aforementioned execution entity may perform electronic beam scanning of the target sea surface area based on the aforementioned antenna module, the aforementioned first-band transceiver module, and the generated multi-channel transmission excitation signals through the following steps:

[0045] The first step involves amplifying and filtering the multiple transmit excitation signals using the antenna unit final-stage transmit module included in the first-band transmit module. In practice, the executing entity can amplify each of the multiple transmit excitation signals using the power amplifier included in the antenna unit final-stage transmit module STRA, and simultaneously filter the amplified signals using an S-band cavity filter (e.g., a bandpass filter or a combination of a low-pass filter and a bandpass filter).

[0046] The second step involves applying phase control to the amplified and filtered multiple transmit excitation signals using the phase shifter included in the final stage of the antenna unit's transmit module, thereby obtaining the controlled transmit excitation signal. In practice, the aforementioned execution entity can apply a preset phase to each transmit excitation signal using the phase shifter included in the first transmit module of the first band, obtaining the phase-shifted transmit excitation signal as the controlled transmit excitation signal.

[0047] It should be noted that the value of the preset phase is determined by scanning the target sea surface area. That is, when it is necessary to point to different angles, the value of the preset phase is updated so that the main lobe turns to the corresponding scanning beam direction.

[0048] The third step involves inputting the controlled transmission excitation signal into the antenna module to generate a first-band phased array transmission beam to scan the target sea surface area. In practice, the actuator can feed the controlled transmission excitation signal into the array element or subarray port of the antenna module, and the antenna array spatially superimposes the signals from each channel to form a directional beam. The signal processing board or the actuator can update the preset phase value according to the scanning sequence, thereby enabling the beam to scan sequentially at various azimuth angles of the target sea surface area.

[0049] Step 103: In response to the antenna module receiving the second-band echo signal, the received second-band echo signal is processed by the second-band transceiver module to generate a four-channel polarized monopulse signal.

[0050] In some embodiments, the execution entity may, in response to the antenna module receiving a second-band echo signal, perform band front-end processing on the received second-band echo signal according to the second-band transceiver module to generate four-channel polarized monopulse signals. The second-band echo signal is transmitted by a cooperative tag installed on the search and rescue target after frequency multiplication of the received first-band signal. In practice, the execution entity can first use a power divider included in the second-band transceiver module to divide the second-band echo signal received by the antenna module into multiple receiving channel signals, and perform basic receiving processing on each receiving channel signal to obtain multiple receiving channel signals. This basic receiving processing may include: bandpass filtering of each receiving channel signal to retain valid C-band signals, low-noise amplification to increase signal amplitude, and then outputting the processed receiving channel signals to the signal processing board for sampling to obtain multiple receiving channel signals. Then, the aforementioned signal processing board sets phase weights and amplitude weights for each receiving channel signal according to the current receiving beam direction to align the channel signals, and sums the weighted multi-channel signals in the horizontal polarization channel and the vertical polarization channel respectively, thereby obtaining the horizontal polarization single pulse channel signal pair and the vertical polarization single pulse channel signal pair as four polarization single pulse channel signals.

[0051] In some optional implementations of certain embodiments, the aforementioned execution entity may perform band front-end processing on the received second-band echo signal according to the aforementioned second-band transceiver module through the following steps to generate a four-channel polarized monopulse signal:

[0052] The first step involves processing the second-band echo signal at the front-end of the second-band transceiver module to obtain the receiving channel signal. This second-band transceiver module also includes a second-band end-stage transceiver module and a second-band end-stage transceiver module. The second-band echo signal is a C-band echo signal. The first second-band end-stage transceiver module can be a C-band end-stage TR module (i.e., a CTRA module). The second-band end-stage transceiver module can be a C-band end-stage TR module (i.e., a CTRB module). The second second-band end-stage transceiver module can be a C-band end-stage TR module (i.e., a CTRC module). In the CTRA, CTRB, and CTRC modules, C represents C-band, TR represents TR module (Transmission / Reception Module), and A, B, and C are simply module designations for differentiation. In practice, the aforementioned execution entity can send the received second-band echo signal into the CTRA module channel. The CTRA module isolates and distributes the transmit and receive paths through a circulator, so that the second-band echo signal enters the low-noise amplification path along the receiving link, and then passes through the low-noise amplifier to improve the signal-to-noise ratio to obtain the receiving channel signal. Finally, the amplified receiving channel signal is output to the CTRB module.

[0053] like Figure 8 The design principle of the first transceiver module of the second-band preamplifier stage is shown below. SPDT represents a single-pole double-throw switch. CH1 represents C-band horizontal polarization channel 1. CH2 represents C-band horizontal polarization channel 2. CV1 represents C-band vertical polarization channel 1. CV2 represents C-band vertical polarization channel 2. One C-band preamplifier TR module (i.e., CTRA module) contains two array dual-polarization final stage transceivers. The four circulators in one CTRA connect to the two dual-polarization arrays. Eight CTRA modules connect to 16 array-element dual-polarization antennas. The four circulators divide the transmit and receive feed channels: one connects to a power amplifier to form the transmit output, and the other connects to a low-noise amplifier (LNA) to receive the echo. The echo is then combined through a single-pole double-throw switch and connected to the final preamplifier beam to form the TR. Each CTRA module consists of four transmit and receive RF channels, internally composed of core components such as a C-band circulator, power amplifier, LNA, and SPDT dual-channel RF switch, as well as corresponding power supply, control, and protection peripheral circuits. The power amplifier mainly performs the final stage amplification of the transmitted RF signal, enabling the RF signal to have the radiation power required for detection. It mainly consists of a power amplifier chip and corresponding matching and auxiliary circuits.

[0054] like Figure 9The design principle of the second-band pre-stage transceiver module is shown below. CH1 represents C-band horizontal polarization channel 1. CH2 represents C-band horizontal polarization channel 2. CH3 represents C-band horizontal polarization channel 3. CH4 represents C-band horizontal polarization channel 4. CH5 represents C-band horizontal polarization channel 5. CH6 represents C-band horizontal polarization channel 6. CH7 represents C-band horizontal polarization channel 7. CH8 represents C-band horizontal polarization channel 8. CBH1 represents C-band horizontal polarization beam channel 1. The first C-band pre-stage TR module (i.e., CTRB module) contains two 8-channel transmit / receive phase shifters. The transmit / receive phase shifters are selected by a switch and connected to eight dual-polarization arrays. The eight vertically polarized channels and the eight horizontally polarized channels are combined into two beam channels, CBH1 and CBV1, respectively, through two 8-channel power dividers. Figure 5 The diagram shows the beamforming path of CBH1. Similarly, the second C-band preamplifier TR module connects to the second group of eight dual-polarized arrays. The eight vertically polarized channels and the eight horizontally polarized channels are combined into two beam channels, CBH2 and CBV2, respectively, through two 8-way power dividers. The CTRB module mainly consists of two dual-channel RF switches (SPDT), a C-band phase shifter, a C-band attenuator, a 1-to-8 power divider, and corresponding peripheral circuits. It primarily performs phase shifting and attenuation control of C-band uplink and downlink RF signals.

[0055] like Figure 10The second-band preamplifier module (CTRC module) illustrates the principle of the following: CBHr1 represents C-band horizontally polarized receiving beam channel 1; CBHr2 represents C-band horizontally polarized receiving beam channel 2; CBVr1 represents C-band vertically polarized receiving beam channel 1; CBVr2 represents C-band vertically polarized receiving beam channel 2; Ct represents C-band transmit excitation. The C-band preamplifier TR module (CTRC module) uses switches to divide the two horizontally polarized and two vertically polarized beam channels of CBH1, CBV1, CBH2, and CBV2 into transmit and receive channels. The receiving channel amplifies the received signal through a low-noise amplifier. A cascaded amplification process involving the final stage, pre-final stage, and pre-final stage ensures a 60dB receiving gain. Four beam channels (CBHr1, CBVr1, CBHr2, and CBVr2) are output to the AD port of a 4-channel signal processing board for acquisition. CBHr1 and CBHr2 (horizontally polarized single-pulse channel signal pairs) constitute horizontally polarized single-pulse angle measurement, and CBVr1 and CBVr2 (vertically polarized single-pulse channel signal pairs) constitute vertically polarized single-pulse angle measurement. The transmitting channel amplifies the transmit excitation signal Ct from the 4-power divider, resulting in a 68dB gain and drive power. When the transmitting channel is selected via a switch and circulator, sufficient transmit power is generated for radiation into space.

[0056] The second step involves performing sub-beamforming processing on the received channel signal using the aforementioned second-band pre-transmitter module to generate four polarized sub-beam channel signals. In practice, the executing entity can use the phase shifter, attenuator, and power divider included in the second-band pre-transmitter module to perform sub-beamforming processing on the received channel signal to generate four polarized sub-beam channel signals.

[0057] The third step involves cascading and amplifying the four polarization sub-beam channel signals using the second-band pre-stage second transceiver module, resulting in four polarization monopulse channel signals. In practice, the aforementioned execution entity can divide the four polarization sub-beam channel signals into transmit and receive channels, cascade and amplify the receive channels, and ultimately output four polarization monopulse channel signals.

[0058] In some optional implementations of certain embodiments, the aforementioned execution entity may perform sub-beamforming processing on the aforementioned multi-channel received signals according to the aforementioned second-band pre-receiver module through the following steps to generate four-channel polarized sub-beam channel signals:

[0059] The first step involves applying phase adjustment to the multi-channel received signals using the second-band phase shifter included in the aforementioned second-band pre-amplifier module. This second-band pre-amplifier module also includes a second-band attenuator and a power divider. In practice, the executing entity can first use an RF switch (e.g., a single-pole double-throw switch, SPDT) within the CTRB module to direct the received signals of each channel into their corresponding phase shift / attenuation control branch. Then, each channel's received signal undergoes phase shift adjustment with a preset phase applied by the C-band phase shifter to form the desired beam pointing. The applied preset phase can be determined by the received beam pointing.

[0060] The second step involves applying amplitude adjustment to the regulated multi-channel received signals using the attenuator included in the aforementioned second-band pre-amplifier module. In practice, the aforementioned actuator can set a controllable attenuation value for each channel, and use the attenuator included in the aforementioned second-band pre-amplifier module to align the amplitudes of the multi-channel received signals.

[0061] The third step involves using a power divider to combine the amplitude-adjusted multi-channel received signals into four polarization sub-beam channel signals. In practice, the aforementioned execution unit can use two 8-channel power dividers to sum the amplitude-adjusted multi-channel received signals (the channel received signals corresponding to the 8 vertically polarized channels and the 8 horizontally polarized channels, respectively) and output four polarization sub-beam channel signals.

[0062] In some optional implementations of certain embodiments, the aforementioned execution entity may, through the following steps, cascade and amplify the four polarized sub-beam channel signals according to the aforementioned second-band pre-stage second transceiver module to obtain four polarized monopulse channel signals:

[0063] The first step is to divide the signals of the four polarization sub-beam channels according to horizontal and vertical polarization and transmit them to the corresponding receiving and transmitting channels. In practice, the above-mentioned execution entity can transmit the four sub-beam channels to the corresponding receiving and transmitting channels (i.e., two beam channels for horizontal polarization and two beam channels for vertical polarization) according to their polarization attributes (i.e., horizontal polarization and vertical polarization).

[0064] The second step is to perform low-noise amplification on each of the four polarization sub-beam channels after the signal is divided. In practice, this is done by using a low-noise amplifier on each sub-beam channel.

[0065] The third step involves dividing the noise-amplified signals of each polarization sub-beam channel into horizontally polarized single-pulse channel signal pairs and vertically polarized single-pulse channel signal pairs, which are then used as four-channel polarized single-pulse channel signals. In practice, the aforementioned execution entity can define the outputs of the two horizontally polarized beam channels as one single-pulse pair (CBHr1, CBHr2), and the outputs of the two vertically polarized beam channels as another single-pulse pair (CBVr1, CBVr2), and output them to the AD interface of the signal processing board in a four-channel format.

[0066] Step 104: Based on the multi-dimensional signal parameters corresponding to the multi-channel transmit excitation signals and the second-band echo signals, extract the frequency domain polarization features of the four polarized single-pulse channel signals to generate a signal frequency domain polarization feature set.

[0067] In some embodiments, the execution entity can extract frequency domain polarization features from the four polarized single-pulse channel signals based on the multi-dimensional signal parameters corresponding to the multiple transmitted excitation signals and the second-band echo signals, thereby generating a signal frequency domain polarization feature set. The multi-dimensional signal parameters may include a scan period index, a scan beam index, a range cell index, and a pulse index range. In practice, the execution entity can use the corresponding multi-dimensional signal parameters as labels to perform a Fast Fourier Transform on each of the four polarized single-pulse channel signals. For each polarized single-pulse channel signal after the transform, the echo signal amplitude value is determined as the signal frequency domain feature, and the relative amplitude standard deviation between the signal pairs corresponding to the horizontal polarization channel and the signal pairs corresponding to the vertical polarization channel is determined as the signal polarization feature. These two values ​​are then concatenated to obtain the signal frequency domain polarization feature.

[0068] In some optional implementations of certain embodiments, the execution entity may perform frequency domain polarization feature extraction on the four polarized single-pulse channel signals based on the multi-dimensional signal parameters corresponding to the multiple transmitted excitation signals and the second-band echo signals, thereby generating a signal frequency domain polarization feature set:

[0069] The first step is to generate information for each detection unit based on the multi-dimensional signal parameters corresponding to the aforementioned multiple transmission excitation signals and the aforementioned second-band echo signals. In practice, firstly, the aforementioned execution entity can determine the scanning period index m according to the scanning control timing of the first-band transmission excitation signals. For example, when the beam pointing sequence completes a preset full-coverage scan, it is recorded as one scanning period, and m is obtained by counting each scanning period. The aforementioned beam pointing sequence can be (θ1, θ2, ..., θb), representing the pointing angle of each S-band transmission. Then, the aforementioned execution entity can determine the scanning beam index i according to the dwell order of the antenna electronic beam within each scanning period, and determine the pulse p according to the pulse transmission trigger time during each beam dwell period. For example, within a scanning period m, the antenna module forms b beam dwelling segments according to the scanning table (i.e., beam pointing sequence), with each beam segment corresponding to a pointing θi. The i-th dwelling segment within the scanning period m is the scanning beam index i, and within each dwelling segment (m, i), p pulses are transmitted according to PRI. The p-th transmit-receive round within that dwelling segment is the pulse index p. Furthermore, the execution entity can set a fixed-length second-band echo receiving window in each pulse round to collect echo signals from different distance ranges. Then, the receiving window is divided into multiple consecutive window segments in the sampling point dimension (i.e., time dimension) according to preset equal time intervals. Each window segment corresponds to a distance unit (the interval distance can be determined by time and signal propagation speed), and these segments are sequentially numbered to obtain the distance unit index j. Thus, each distance unit index j corresponds to a fixed sampling interval within the receiving window, representing the spatial distance range corresponding to the echo signal within that interval. Therefore, the aforementioned execution entity can generate a multidimensional echo index structure consisting of (m, i, p, j), and generate information for each detection unit according to this index structure. Each detection unit information may include (m, i, j) and the pulse set range p∈(1, ..., P) corresponding to that detection unit.

[0070] The second step involves constructing data from the four polarized single-pulse channel signals based on the information from each detection unit, resulting in a set of polarized single-pulse channel signal groups. Each polarized single-pulse channel signal group corresponds to one detection unit information. In practice, firstly, for each detection unit information, the execution entity can synchronously sample the four polarized single-pulse channel signals and bind a corresponding (m, i, p) timing identifier to each sampling result. Secondly, the sampling results of each pulse round p can be divided into the corresponding distance unit range according to the distance unit index j. Thirdly, the execution entity can use the detection unit information (m, i, j) as an index to extract the channel sampling results of multiple pulse rounds (p=1…P) corresponding to that detection unit from the four channels, and concatenate adjacent sampling signals in the same channel in terms of sampling time into a single polarized single-pulse channel signal, thus obtaining a set of polarized single-pulse channel signals. Finally, the obtained sets of polarized single-pulse channel signal groups are combined.

[0071] Third, for each polarized single-pulse channel signal group in the above-mentioned set of polarized single-pulse channel signal groups, perform the following feature extraction steps:

[0072] The first sub-step involves transforming each polarized single-pulse channel signal in the polarized single-pulse channel signal group to obtain the transformed channel signals. In practice, the aforementioned execution entity can first accumulate the polarized single-pulse channel signal of each channel in the polarized single-pulse channel signal group along the pulse dimension p to improve the signal-to-noise ratio and reduce the impact of instantaneous fluctuations on subsequent features. As an example, the above accumulation process can be incoherent accumulation: that is, extracting the frequency band energy from each sampling result in each polarized single-pulse channel signal and averaging it to obtain the corresponding transformed channel signal.

[0073] The second sub-step involves extracting frequency domain features from each of the transformed channel signals to generate signal frequency domain features. In practice, firstly, the execution entity can perform frequency domain transformation processing (e.g., FFT transformation) on each transformed channel signal to obtain a signal spectrum representation. Then, frequency domain features (e.g., band energy, peak value, peak-to-average power ratio) can be calculated within a preset harmonic frequency band to characterize the echo intensity and spectral concentration of the detection unit within the harmonic frequency band. Subsequently, the execution entity concatenates the frequency domain features corresponding to the four channels in a preset order to form the signal frequency domain features.

[0074] The third sub-step involves generating signal polarization characteristics based on the transformed channel signals described above.

[0075] The fourth sub-step involves concatenating the above-mentioned signal frequency domain features with the above-mentioned signal polarization features to obtain the signal frequency domain polarization features.

[0076] The fourth step is to determine the frequency domain polarization features of each generated signal as a set of signal frequency domain polarization features.

[0077] In some optional implementations of certain embodiments, the aforementioned execution entity can generate signal polarization characteristics based on the transformed channel signals through the following steps:

[0078] The first step involves classifying the polarization attributes of each transformed channel signal to obtain a first transformed channel signal pair and a second transformed channel signal. The first transformed channel signal pair corresponds to the horizontally polarized monopulse channel signal pair, and the second transformed channel signal pair corresponds to the vertically polarized monopulse channel signal pair. In practice, the executing entity can classify the polarization attributes of the four transformed channel signals based on a fixed channel mapping relationship: the two transformed channel signals corresponding to the horizontally polarized monopulse channel signal pair are grouped into a first transformed channel signal pair, and the two transformed channel signals corresponding to the vertically polarized monopulse channel signal pair are grouped into a second transformed channel signal pair, thus obtaining the channel signal pairs corresponding to horizontal polarization and vertical polarization.

[0079] The second step is to generate horizontal polarization energy based on the first transformed channel signal pair. In practice, the execution entity can determine the harmonic frequency band energies corresponding to the two signals included in the first transformed channel signal pair, obtain two harmonic frequency band energy values, and sum the two harmonic frequency band energy values ​​to obtain the horizontal polarization energy of the detection unit, thereby characterizing the echo intensity of the detection unit in horizontal polarization with a single energy metric.

[0080] The third step is to generate vertical polarization energy based on the aforementioned second transformed channel signal pair. In practice, the aforementioned execution entity can determine the harmonic frequency band energies corresponding to the two signals included in the second transformed channel signal pair, obtain two harmonic frequency band energy values, and sum the two harmonic frequency band energy values ​​to obtain the vertical polarization energy of the detection unit, thereby characterizing the echo intensity of the detection unit in vertical polarization with a single energy metric.

[0081] The fourth step involves generating the mean, variance, mean, and variance of vertical polarization energy based on the detection unit information corresponding to the aforementioned polarization single-pulse channel signal group, the information of adjacent detection units, the horizontal polarization energy, and the vertical polarization energy. In practice, the executing entity can first determine the set of adjacent detection unit information based on the current detection unit information (m, i, j) to serve as a statistical window. For example, this set of adjacent detection unit information can be a temporal neighborhood, i.e., with (i, j) fixed, selecting detection unit information from (m−M+1, i, j) to (m, i, j) over multiple consecutive scan cycles. Then, within the statistical window, the executing entity determines the mean and variance of the horizontal polarization energy sequence and the vertical polarization energy sequence, respectively, thereby obtaining the mean, variance, and variance of the horizontal polarization energy.

[0082] The fifth step involves generating the standard deviations of the relative amplitudes of horizontal and vertical polarization based on the aforementioned mean, variance, and variance of vertical and horizontal polarization energy. In practice, the implementing entity can first take the square roots of the variances of horizontal and vertical polarization energy to obtain their standard deviations. Then, each standard deviation is divided by its corresponding energy mean and normalized using a zero-preservation constant ε, thus generating the standard deviations of the relative amplitudes of horizontal and vertical polarization, making them dimensionless statistics to characterize the relative fluctuations under different sea state intensities.

[0083] The sixth step is to generate polarization-derived features based on the aforementioned standard deviations of horizontal and vertical polarization relative amplitudes. In practice, the executing entity can first use the absolute value of the difference between the aforementioned standard deviations of horizontal and vertical polarization relative amplitudes as the polarization fluctuation difference feature, and the ratio of the two as the polarization fluctuation ratio feature, thereby obtaining polarization-derived features that are more sensitive to the difference between the target and sea clutter.

[0084] Step 7: Combine the above-mentioned horizontal polarization energy, vertical polarization energy, horizontal polarization relative amplitude standard deviation, vertical polarization relative amplitude standard deviation, and polarization derived features into signal polarization features.

[0085] Step 105: Based on the pre-built target detector, adaptive target detection is performed on the signal frequency domain polarization feature set to generate search and rescue target detection results.

[0086] In some embodiments, the execution entity can perform adaptive target detection on the signal frequency domain polarization feature set based on a pre-built target detector to generate search and rescue target detection results. The target detector can be an adaptive detector used to detect the presence of a search and rescue target in the signal features. The target detector can be a VI-CFAR detector or a CFAR detector. In practice, the execution entity can directly input the signal frequency domain polarization feature set into the target detector to generate search and rescue target detection results.

[0087] In some optional implementations of certain embodiments, the aforementioned execution entity may perform adaptive target detection on the aforementioned signal frequency domain polarization feature set based on a pre-built target detector through the following steps to generate search and rescue target detection results:

[0088] The first step is to construct spatial features for the aforementioned signal frequency domain polarization feature set based on the generated information of each detection unit, thus obtaining the signal feature space. In practice, the aforementioned execution entity can first arrange the signal frequency domain polarization feature set spatially and temporally according to the scan period index m, scan beam index i, and distance unit index j contained in the information of each detection unit. Specifically, the signal frequency domain polarization features corresponding to each detection unit can be mapped into the feature space according to their (m, i, j) index positions, thereby forming an ordered signal frequency domain polarization feature space in the scan period dimension, beam dimension, and distance dimension as the signal feature space, so that adjacent detection units have a clear adjacency relationship in the feature field.

[0089] The second step is to perform detection steps for each generated detection unit information:

[0090] The first sub-step involves determining the information of each adjacent detection unit and the information of a reference unit in the constructed signal feature space based on the aforementioned detection unit information. In practice, the executing entity can select the detection unit represented by the aforementioned detection unit information as the current detection unit in the aforementioned signal feature space, and determine each detection unit adjacent to the current detection unit as a protection unit and a reference unit in the aforementioned signal feature space according to a preset neighborhood rule. The protection unit is used to prevent the target signal from leaking into the background estimation, and the reference unit is used to characterize the sea clutter background characteristics around the current detection unit. The protection unit and reference unit can preferably be selected in the distance unit dimension and / or the scan period dimension. The preset neighborhood rule can be that, in the distance unit dimension and / or the scan period dimension, with the current detection unit as the center, each adjacent detection unit is considered as a protection unit, and each detection unit separated by one detection unit is also considered as a protection unit.

[0091] The second sub-step involves identifying the feature distribution of the signal frequency domain polarization characteristics corresponding to the aforementioned monitoring unit information to determine the sea clutter background type. In practice, firstly, the executing entity can generate the Euclidean distance between the signal frequency domain polarization characteristics corresponding to the aforementioned monitoring unit information and the signal frequency domain polarization characteristics corresponding to each reference unit, and determine the average distance. Then, in response to determining that the average distance is greater than or equal to a preset feature change threshold, the sea clutter background type is determined to be non-stationary, indicating that the sea clutter distribution in the corresponding area is uneven. Finally, in response to determining that the average distance is less than or equal to a preset feature change threshold, the sea clutter background type is determined to be stationary, indicating that the sea clutter distribution in the corresponding area is uniform.

[0092] The third sub-step involves adaptively estimating the frequency-domain polarization features of the signals corresponding to each reference cell based on the determined sea clutter background type, thereby obtaining the detection background features. In practice, after identifying the sea clutter background type, the aforementioned execution entity can perform corresponding background estimation steps for the frequency-domain polarization features of the signals in each reference cell for different sea clutter background types. Specifically, when the sea clutter background type represents a stationary type, the frequency-domain polarization features of the signals corresponding to each reference cell can be estimated by taking the mean or the median of each feature value to obtain the detection background features. When the sea clutter background type represents a non-stationary type, the frequency-domain polarization features of the signals corresponding to each reference cell can be weighted and summed using preset feature weight coefficients to obtain the detection background features that match the current sea clutter background.

[0093] The fourth sub-step involves generating the detection threshold value corresponding to the target detector based on the aforementioned background detection features and the signal frequency domain polarization features corresponding to each protection unit. In practice, the executing entity can generate the average Euclidean distance between the signal frequency domain polarization features corresponding to each protection unit as the strategy selection distance. Then, in response to determining that the strategy selection distance is greater than or equal to the first threshold, the executing entity can use the cell average CFAR (i.e., CA-CFAR algorithm, Cell Averaging-Constant False Alarm Rate) detection algorithm to generate the detection threshold value corresponding to the target detector for the signal frequency domain polarization features corresponding to each protection unit (i.e., averaging the same type of value for each feature value within the signal frequency domain polarization features corresponding to each protection unit, summing the average values ​​of all types of feature values ​​as the detection threshold value, thereby characterizing the average level of sea clutter background in the neighborhood of the detection unit). Subsequently, in response to determining that the strategy selection distance is less than the first threshold and greater than or equal to the second threshold, the aforementioned execution entity can generate the detection threshold value corresponding to the target detector using the maximum selection CFAR (i.e., GO-CFAR, Greatest Of Cell Averaging-Constant False Alarm Rate) detection algorithm and the signal frequency domain polarization features corresponding to each protection unit. This involves generating the sum of all feature values ​​in each signal frequency domain polarization feature and then selecting the maximum value from the generated feature sum as the detection threshold value. Finally, in response to determining that the strategy selection distance is less than the first threshold and greater than or equal to the second threshold, the aforementioned execution entity can generate the detection threshold value corresponding to the target detector using the minimum selection CFAR (i.e., SO-CFAR, Smallest Of Cell Averaging-Constant False Alarm Rate) detection algorithm and the signal frequency domain polarization features corresponding to each protection unit. This involves generating the sum of all feature values ​​in each signal frequency domain polarization feature and then selecting the minimum value from the generated feature sum as the detection threshold value.

[0094] The fifth sub-step involves inputting the signal frequency domain polarization features corresponding to the aforementioned monitoring unit into the aforementioned target detector to obtain the unit detection result. In practice, the aforementioned execution entity can compare the signal frequency domain polarization features corresponding to the current detection unit with the calculated detection threshold. When the aforementioned signal frequency domain polarization features meet the preset detection conditions (i.e., the sum of all feature values ​​within the aforementioned signal frequency domain polarization features is greater than or equal to the detection threshold value), it is determined that a search and rescue target exists in the current detection unit, and the information of the current detection unit is taken as the unit detection result.

[0095] The third step is to determine the generated detection results of each unit as the search and rescue target detection results. This yields information on each detection unit where a search and rescue target exists, and the corresponding sea surface area is determined using this information.

[0096] The various embodiments of this disclosure have the following beneficial effects: The maritime search and rescue target detection method based on harmonic radar in some embodiments of this disclosure adopts S / C harmonic radar and a dual-polarization phased array structure. By enabling the search and rescue target to generate an acceptable harmonic echo, sea clutter energy is suppressed in both the frequency band and polarization physical dimensions, thereby achieving stable detection of the search and rescue target. Specifically, the reason for the poor stability of the related search and rescue target detection is that, under complex sea conditions, the sea surface will generate strong linear scattering echoes of the electromagnetic waves emitted by the radar. The energy of these echoes is much higher than the radar scattering echoes of small search and rescue targets such as people in the water or life-saving devices. This causes the target echoes to be submerged by sea clutter at the receiving end, making it difficult for traditional radar based on co-frequency reflection to physically distinguish the target from the sea surface background, thus making it difficult to stably detect search and rescue targets with extremely small radar cross-sections. Based on this, some embodiments of the maritime search and rescue target detection method based on harmonic radar disclosed herein firstly generate multiple transmission excitation signals through a signal processing board and a first-band transceiver module included in the harmonic radar equipment. The harmonic radar equipment further includes an antenna module and a second-band transceiver module. Thus, by uniformly generating and controlling the multiple transmission excitation signals through the signal processing board, the first-band transmission link maintains stable signal detection during the scanning of the target sea surface area. Then, based on the antenna module, the first-band transceiver module, and the generated multiple transmission excitation signals, an electronic beam scan is performed on the target sea surface area, where the target sea surface area is the area where target search and rescue is underway. Therefore, by cooperating with the antenna module and the first-band transceiver module, the transmitted signals can be sequentially irradiated onto the target sea surface area with beams of different directions, allowing the transmitted signals to detect the sea surface in sections according to direction, avoiding spatial overlap of echoes, thereby improving signal detection stability. Subsequently, in response to the antenna module receiving the second-band echo signal, the second-band transceiver module performs band front-end processing on the received second-band echo signal to generate four polarized monopulse channel signals. The second-band echo signal is transmitted by a cooperative tag installed on the search and rescue target after frequency doubling the received first-band signal. Thus, the second-band transceiver module can receive the frequency-doubled echo generated by the cooperative tag and decompose it into multiple polarized monopulse channels, enabling the search and rescue target to form an observable echo signal in the second band. Since sea clutter and floating objects do not generate frequency-doubled echoes and are significantly suppressed, the echo signal between the search and rescue target and the sea surface background clutter can be significantly distinguished at the receiving end. Next, based on the multi-dimensional signal parameters corresponding to the multiple transmitted excitation signals and the second-band echo signal, frequency domain polarization features are extracted from the four polarized monopulse channel signals to generate a signal frequency domain polarization feature set.Therefore, by performing spectral analysis on the four echo signals within the harmonic band and extracting features based on changes in polarization direction, the search and rescue targets carrying cooperative tags differ from sea clutter in frequency distribution and polarization behavior. This transforms the originally highly fluctuating echo signals into more stable and easily discriminable feature vectors. Finally, based on a pre-constructed target detector, adaptive target detection is performed on the aforementioned signal frequency domain polarization feature set to generate search and rescue target detection results. Thus, an adaptive threshold target detector can be used to monitor the signal frequency domain polarization feature set, automatically adjusting the discrimination criteria according to the strength and local changes of sea clutter. This maintains a low false alarm rate under different sea states while improving the detection capability of weak search and rescue targets, thereby achieving stable detection of search and rescue targets.

[0097] Further reference Figure 11 As an implementation of the methods shown in the above figures, this disclosure provides some embodiments of a maritime search and rescue target detection device based on harmonic radar. These device embodiments are similar to... Figure 1 Corresponding to the method embodiments shown, this harmonic radar-based maritime search and rescue target detection device can be specifically applied to various electronic devices.

[0098] like Figure 11 As shown, a maritime search and rescue target detection device 1100 based on harmonic radar in some embodiments includes: a generation unit 1101, a scanning unit 1102, a band front-end processing unit 1103, a feature extraction unit 1104, and a target detection unit 1105. The generation unit 1101 is configured to generate multiple transmission excitation signals using a signal processing board and a first-band transceiver module included in the harmonic radar device. The harmonic radar device further includes an antenna module and a second-band transceiver module. The scanning unit 1102 is configured to perform electronic beam scanning on a target sea surface area based on the antenna module, the first-band transceiver module, and the generated multiple transmission excitation signals. The target sea surface area is the sea surface area where target search and rescue is underway. The band front-end processing unit 1103 is configured to, in response to the antenna module receiving a second-band echo signal, process the received second-band echo signal using the second-band transceiver module. The second-band echo signal undergoes band front-end processing to generate four-channel polarized monopulse signals. The second-band echo signal is emitted by a cooperative tag installed on the search and rescue target after frequency doubling the received first-band signal. The feature extraction unit 1104 is configured to extract frequency-domain polarization features from the four-channel polarized monopulse signals based on the multi-dimensional signal parameters corresponding to the multiple transmission excitation signals and the second-band echo signal, to generate a signal frequency-domain polarization feature set. The target detection unit 1105 is configured to perform adaptive target detection on the signal frequency-domain polarization feature set based on a pre-constructed target detector, to generate a search and rescue target detection result.

[0099] It is understandable that the units described in the harmonic radar-based maritime search and rescue target detection device 1100 are related to the reference... Figure 1 The steps in the described method correspond accordingly. Therefore, the operations, features, and beneficial effects described above for the method also apply to the harmonic radar-based maritime search and rescue target detection device 1100 and the units contained therein, and will not be repeated here.

[0100] The following is for reference. Figure 12 It shows a schematic diagram of the structure of an electronic device 1200 (e.g., a computing device) suitable for implementing some embodiments of the present disclosure. Figure 12 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments of this disclosure.

[0101] like Figure 12 As shown, the electronic device 1200 may include a processing unit 1201 (e.g., a central processing unit, a graphics processor, etc.) that can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1202 or a program loaded from a storage device 1208 into a random access memory (RAM) 1203. The RAM 1203 also stores various programs and data required for the operation of the electronic device 1200. The processing unit 1201, ROM 1202, and RAM 1203 are interconnected via a bus 1204. An input / output (I / O) interface 1205 is also connected to the bus 1204.

[0102] Typically, the following devices can be connected to I / O interface 1205: input devices 1206 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 1207 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1208 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1209. Communication device 1209 allows electronic device 1200 to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 12 An electronic device 1200 with various devices is shown; however, it should be understood that it is not required to implement or possess all of the devices shown. More or fewer devices may be implemented or possessed alternatively. Figure 12 Each box shown can represent a device or multiple devices as needed.

[0103] In particular, according to some embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, some embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication device 1209, or installed from storage device 1208, or installed from ROM 1202. When the computer program is executed by processing device 1201, it performs the functions defined above in the methods of some embodiments of this disclosure.

[0104] It should be noted that, in some embodiments of this disclosure, the computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In some embodiments of this disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In some embodiments of this disclosure, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.

[0105] In some implementations, clients and servers can communicate using any currently known or future-developed network protocol such as HTTP (Hypertext Transfer Protocol) and can interconnect with digital data communication (e.g., communication networks) of any form or medium. Examples of communication networks include local area networks (“LANs”), wide area networks (“WANs”), the Internet (e.g., the Internet of Things), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks), as well as any currently known or future-developed networks.

[0106] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device. The aforementioned computer-readable medium carries one or more programs that, when executed by the electronic device, cause the electronic device to: generate multiple transmission excitation signals via the signal processing board and first-band transceiver module included in the harmonic radar device, wherein the harmonic radar device further includes: an antenna module and a second-band transceiver module; perform electronic beam scanning of a target sea surface area based on the antenna module, the first-band transceiver module, and the generated multiple transmission excitation signals, wherein the target sea surface area is a sea surface area where target search and rescue is underway; and, in response to the antenna module receiving a second-band echo signal, perform electronic beam scanning of the target sea surface area. The second-band transceiver module performs band front-end processing on the received second-band echo signal to generate four polarized monopulse channel signals. The second-band echo signal is transmitted after the cooperative tag installed on the search and rescue target has multiplied the frequency of the received first-band signal. Based on the multi-dimensional signal parameters corresponding to the multiple transmission excitation signals and the second-band echo signal, frequency domain polarization features are extracted from the four polarized monopulse channel signals to generate a signal frequency domain polarization feature set. Adaptive target detection is then performed on the signal frequency domain polarization feature set using a pre-constructed target detector to generate search and rescue target detection results.

[0107] Computer program code for performing operations of some embodiments of this disclosure can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0108] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated 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 the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0109] The functions described above in this document can be performed at least in part by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip (SoCs), complex programmable logic devices (CPLDs), and so on.

[0110] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A method for detecting maritime search and rescue targets based on harmonic radar, characterized in that, include: The harmonic radar device includes a signal processing board and a first-band transceiver module, which generate multiple transmission excitation signals. The harmonic radar device also includes an antenna module and a second-band transceiver module. Based on the antenna module, the first band transceiver module, and the generated multi-channel transmission excitation signals, an electronic beam scan is performed on the target sea surface area, wherein the target sea surface area is the sea surface area where target search and rescue is underway; In response to the antenna module receiving a second-band echo signal, the received second-band echo signal is processed by the second-band transceiver module to generate a four-channel polarized monopulse signal. The process of processing the received second-band echo signal to generate the four-channel polarized monopulse signal includes: The second band transceiver module includes a second band front-end first transceiver module, which performs transceiver front-end processing on the second band echo signal to obtain a multi-channel received signal. The second band transceiver module also includes a second band end front-end transceiver module and a second band front-end second transceiver module. According to the second-band pre-receiver module, the multi-channel received signal is subjected to sub-beam synthesis processing to generate four-channel polarized sub-beam signals. According to the second front-end second receiving module of the second band, the four polarized sub-beam channel signals are cascaded and amplified to obtain four polarized single pulse channel signals. The second band echo signal is emitted by the cooperative tag installed on the search and rescue target after frequency multiplication of the received first band signal. Based on the multi-dimensional signal parameters corresponding to the multiple transmitted excitation signals and the second-band echo signals, frequency domain polarization feature extraction is performed on the four polarized single-pulse channel signals to generate a signal frequency domain polarization feature set. The step of extracting frequency domain polarization features from the four polarized single-pulse channel signals based on the multi-dimensional signal parameters corresponding to the multiple transmitted excitation signals and the second-band echo signals to generate the signal frequency domain polarization feature set includes: Based on the multi-dimensional signal parameters corresponding to the multi-channel transmission excitation signals and the second band echo signals, information for each detection unit is generated. Based on the information from each detection unit, data is constructed from the four polarized single-pulse channel signals to obtain a set of polarized single-pulse channel signals. For each polarized single-pulse channel signal group in the set of polarized single-pulse channel signal groups, the following feature extraction steps are performed: Each polarized single-pulse channel signal in the polarized single-pulse channel signal group is transformed to obtain the transformed channel signals. Frequency domain features are extracted from each of the transformed channel signals to generate signal frequency domain features; Based on the transformed channel signals, signal polarization features are generated, wherein generating signal polarization features based on the transformed channel signals includes: The polarization attributes of each transformed channel signal are classified to obtain the first transformed channel signal pair and the second transformed channel signal pair. Based on the first transformed channel signal pair, horizontal polarization energy is generated; Based on the second transformed channel signal pair, vertical polarization energy is generated; Based on the detection unit information corresponding to the polarization single pulse channel signal group, the information of each adjacent detection unit, the horizontal polarization energy, and the vertical polarization energy, the mean value of vertical polarization energy, the variance of vertical polarization energy, the mean value of horizontal polarization energy, and the variance of horizontal polarization energy are generated. Based on the mean vertical polarization energy, the variance of vertical polarization energy, the mean horizontal polarization energy, and the variance of horizontal polarization energy, the standard deviation of the relative amplitude of horizontal polarization and the standard deviation of the relative amplitude of vertical polarization are generated. Based on the standard deviation of the relative amplitude of horizontal polarization and the standard deviation of the relative amplitude of vertical polarization, polarization-derived features are generated; The horizontal polarization energy, the vertical polarization energy, the standard deviation of the horizontal polarization relative amplitude, the standard deviation of the vertical polarization relative amplitude, and the polarization derived features are concatenated to form the signal polarization features; The signal frequency domain features are concatenated with the signal polarization features to obtain the signal frequency domain polarization features; The frequency domain polarization features of each generated signal are defined as a set of signal frequency domain polarization features; Based on a pre-built target detector, adaptive target detection is performed on the signal frequency domain polarization feature set to generate search and rescue target detection results. This process includes: Based on the generated information of each detection unit, spatial features are constructed on the signal frequency domain polarization feature set to obtain the signal feature space; For each generated detection unit information, perform the following detection steps: Based on the detection unit information, information on each adjacent detection unit and reference unit is determined in the constructed signal feature space. The protection unit is used to prevent the target signal from leaking into the background estimation, and the reference unit is used to characterize the sea clutter background characteristics around the current detection unit. The protection unit and the reference unit are selected in the distance unit dimension and / or scan period dimension according to a preset neighborhood rule. The preset neighborhood rule is that, with the current detection unit as the center, each adjacent detection unit is used as a protection unit, and each detection unit separated by one detection unit is used as a reference unit. The signal frequency domain polarization features corresponding to the detection unit information are identified by feature distribution recognition to determine the type of sea clutter background; Based on the determined sea clutter background type, adaptive background estimation is performed on the frequency domain polarization characteristics of the signal corresponding to each reference unit to obtain the detection background characteristics; Based on the detection background features and the signal frequency domain polarization features corresponding to each protection unit, a detection threshold value corresponding to the target detector is generated. The frequency domain polarization features of the signal corresponding to the detection unit are input to the target detector corresponding to the detection threshold to obtain the unit detection result; The detection results of each generated unit are determined as the detection results of the search and rescue target.

2. The method according to claim 1, characterized in that, The harmonic radar equipment includes a signal processing board and a first-band transceiver module, which generate multiple transmission excitation signals, including: The signal processing board generates a first-band linear frequency modulation waveform according to the preset first-band signal parameters. The first band linear frequency modulation waveform is converted from digital to analog via the onboard interface of the signal processing board to generate the first band transmission excitation signal. The first band transmission excitation module, which includes the first band transmission module, amplifies the power of the first band transmission excitation signal to generate multiple transmission excitation signals.

3. The method according to claim 1, characterized in that, The step of performing electronic beam scanning of the target sea surface area based on the antenna module, the first band transceiver module, and the generated multi-channel transmission excitation signals includes: According to the antenna unit final stage transmission module included in the first band transmission module, the multiple transmission excitation signals are amplified and filtered in the final stage. According to the phase shifter included in the final stage of the antenna unit's transmitting and receiving module, phase control is applied to the amplified and filtered multi-channel transmitting excitation signals to obtain the controlled transmitting excitation signals; The control-driven transmission excitation signal is input to the antenna module to generate a first-band phased array transmission beam to scan the target sea surface area.

4. The method according to claim 1, characterized in that, The step of performing sub-beamforming processing on the multi-channel received signal according to the second-band pre-transmitter module to generate four-channel polarized sub-beam signals includes: Phase adjustment is applied to the multi-channel received signal according to the second-band phase shifter included in the second-band pre-transmitter module. The second-band pre-transmitter module also includes a second-band attenuator and a power divider. The amplitude of the adjusted multi-channel received signal is adjusted according to the attenuator included in the pre-terminal receiving module; The multi-channel received signals, after amplitude adjustment, are combined into four polarization sub-beam channel signals using a power divider.

5. The method according to claim 1, characterized in that, The method involves cascading and amplifying the four polarized sub-beam channel signals according to the second-band pre-stage second transceiver module to obtain four polarized single-pulse channel signals, including: According to horizontal and vertical polarization, the signals of the four polarization sub-beam channels are divided and transmitted to the corresponding receiving and transmitting channels. The signal of each polarization sub-beam channel in the divided four polarization sub-beam channels is amplified with low noise. The signals of each polarization sub-beam channel, after low-noise amplification, are divided into horizontal polarization monopulse channel signal pairs and vertical polarization monopulse channel signal pairs, and are used as four polarization monopulse channel signals.

6. A maritime search and rescue target detection device based on harmonic radar, characterized in that, include: The generation unit is configured to generate multiple transmission excitation signals through the signal processing board and the first band transceiver module included in the harmonic radar device, wherein the harmonic radar device further includes: an antenna module and a second band transceiver module. The scanning unit is configured to perform electronic beam scanning on the target sea surface area based on the antenna module, the first band transceiver module and the generated multi-channel transmission excitation signal, wherein the target sea surface area is the sea surface area where target search and rescue is underway; A band front-end processing unit is configured to, in response to the antenna module receiving a second-band echo signal, perform band front-end processing on the received second-band echo signal according to the second-band transceiver module to generate four-channel polarized monopulse signals. The step of performing band front-end processing on the received second-band echo signal according to the second-band transceiver module to generate four-channel polarized monopulse signals includes: performing transceiver front-end processing on the second-band echo signal through a second-band pre-stage first transceiver module included in the second-band transceiver module to obtain multi-channel signals. The receiving signal includes a second-band transceiver module, which further comprises a second-band pre-stage transceiver module and a second-band pre-stage second transceiver module. The second-band pre-stage transceiver module performs sub-beamforming processing on the multi-channel received signal to generate four polarized sub-beam channel signals. The second-band pre-stage second transceiver module cascades and amplifies the four polarized sub-beam channel signals to obtain four polarized single-pulse channel signals. The second-band echo signal is emitted after the received first-band signal is frequency-multiplied by a cooperative tag installed on the search and rescue target. The feature extraction unit is configured to perform frequency domain polarization feature extraction on the four polarized single-pulse channel signals based on the multi-dimensional signal parameters corresponding to the multi-channel transmit excitation signals and the second-band echo signals, to generate a signal frequency domain polarization feature set. The step of performing frequency domain polarization feature extraction on the four polarized single-pulse channel signals based on the multi-dimensional signal parameters corresponding to the multi-channel transmit excitation signals and the second-band echo signals to generate the signal frequency domain polarization feature set includes: generating information for each detection unit based on the multi-dimensional signal parameters corresponding to the multi-channel transmit excitation signals and the second-band echo signals; and generating information for each detection unit based on the multi-dimensional signal parameters corresponding to the multi-channel transmit excitation signals and the second-band echo signals. Meta-information is used to construct data from the four polarized single-pulse channel signals to obtain a set of polarized single-pulse channel signal groups. For each polarized single-pulse channel signal group in the set, the following feature extraction steps are performed: transforming each polarized single-pulse channel signal in the set to obtain transformed channel signals; extracting frequency domain features from each transformed channel signal to generate signal frequency domain features; and generating signal polarization features based on each transformed channel signal, wherein generating signal polarization features based on each transformed channel signal includes: extracting frequency domain features from each transformed channel signal to generate signal frequency domain features. The channel signals are classified according to their polarization attributes to obtain a first transformed channel signal pair and a second transformed channel signal pair. Based on the first transformed channel signal pair, horizontal polarization energy is generated. Based on the second transformed channel signal pair, vertical polarization energy is generated. Based on the detection unit information corresponding to the polarized single-pulse channel signal group, the information of adjacent detection units, the horizontal polarization energy, and the vertical polarization energy, the mean vertical polarization energy, the variance vertical polarization energy, the mean horizontal polarization energy, and the variance horizontal polarization energy are generated. Based on the mean vertical polarization energy, the variance vertical polarization energy, the mean horizontal polarization energy, and the variance horizontal polarization energy... The variance is used to generate the standard deviation of the relative amplitude of horizontal polarization and the standard deviation of the relative amplitude of vertical polarization; based on the standard deviation of the relative amplitude of horizontal polarization and the standard deviation of the relative amplitude of vertical polarization, polarization derived features are generated; the horizontal polarization energy, the vertical polarization energy, the standard deviation of the relative amplitude of horizontal polarization, the standard deviation of the relative amplitude of vertical polarization, and the polarization derived features are concatenated to form signal polarization features; based on the signals of each transformed channel, signal polarization features are generated; the signal frequency domain features are concatenated with the signal polarization features to obtain signal frequency domain polarization features; the generated signal frequency domain polarization features are determined as a set of signal frequency domain polarization features; A target detection unit is configured to perform adaptive target detection on the signal frequency domain polarization feature set based on a pre-built target detector to generate search and rescue target detection results. The adaptive target detection on the signal frequency domain polarization feature set based on the pre-built target detector to generate search and rescue target detection results includes: constructing spatial features on the signal frequency domain polarization feature set based on the generated detection unit information to obtain a signal feature space; for each generated detection unit information, performing the following detection steps: determining each adjacent detection unit information and reference unit information in the constructed signal feature space based on the detection unit information, wherein a protection unit is used to prevent target signal leakage to background estimation, and a reference unit is used to characterize the sea clutter background characteristics around the current detection unit, and the protection unit and reference unit are separated by a preset neighborhood rule in the distance unit dimension. The selection is performed along the distance unit and / or scanning period dimension. The preset neighborhood rule is that, with the current detection unit as the center, each adjacent detection unit is considered as a protection unit, and each detection unit separated by one detection unit is considered as a reference unit. The signal frequency domain polarization features corresponding to the detection unit information are used to identify the feature distribution and determine the sea clutter background type. Based on the determined sea clutter background type, adaptive background estimation is performed on the signal frequency domain polarization features corresponding to each reference unit to obtain the detection background features. Based on the detection background features and the signal frequency domain polarization features corresponding to each protection unit, a detection threshold value corresponding to the target detector is generated. The signal frequency domain polarization features corresponding to the detection unit are input to the target detector corresponding to the detection threshold value to obtain the unit detection result. The generated unit detection results are determined as the search and rescue target detection results.

7. An electronic device, characterized in that, include: One or more processors; A storage device on which one or more programs are stored; When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in any one of claims 1 to 5.

8. A computer-readable medium, characterized in that, It stores a computer program thereon, wherein the computer program, when executed by a processor, implements the method as described in any one of claims 1 to 5.

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