A multistatic active sonar detection method

Abstract

The application discloses a kind of multistatic active sonar detection methods, it is related to active sonar detection field, the multistatic active sonar detection method of the present application includes: step 1: transmitter S launches sound source information;Step 2: receiver R receives direct wave and target echo;Step 3: judge target T is located on the circumscribed ellipse with transmitter S and receiver R as focus;Compared with prior art, the beneficial effects of the present application are: the present application uses communication-detection composite waveform, the waveform parameters, sound source position and transmission time are encoded and modulated after being embedded in the detection waveform, and then sent out, the receiver obtains these information by demodulation decoding, restores the original transmission waveform for echo detection at the same time, and uses sound source space-time information to carry out target positioning calculation;It does not depend on external communication link to carry out sound source space-time information synchronization, so it has wide adaptability, and can fully utilize the sound pulses emitted by different horizontal sound sources in formation to carry out echo target detection.

Description

Technical Field

[0001] This invention relates to the field of active sonar detection, specifically a multi-base active sonar detection method. Background Technology

[0002] In a multistatic active sonar system, the transmitting source and the receiver are spatially separated: one or more sources emit sound, and multiple receivers receive the reflected echoes from the target at different locations.

[0003] One of the challenges is achieving remote synchronization between the transmitter and receiver using appropriate real-time communication methods. Existing bistatic sonar systems for real-time monitoring of port and waterway depth employ a high-precision GPS timing module to provide timing information, enabling synchronized operation between the transmitter and receiver.

[0004] In application scenarios such as between multiple anti-submarine helicopters dipping sonars, and between surface ship sonars and shipborne anti-submarine helicopter dipping sonars, the above links can exchange regional situational information such as platform positions. However, they are not specifically designed for time synchronization and usually adopt transmission control strategies such as checksum and retransmission. The delay is uncertain and they are difficult to use for time synchronization.

[0005] Furthermore, when the sonar receiver is located on an underwater mobile platform (submarine, UUV, etc.), it is impossible to synchronize with the transmitting sound source using an external wired or radio link, so it is necessary to improve the spatiotemporal information synchronization between the receiver and the transmitting sound source. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-base active sonar detection method to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A multi-base active sonar detection method includes:

[0009] Step 1: Transmitter S transmits sound source information;

[0010] Step 2: Receiver R receives the direct wave and the target echo;

[0011] Step 3: Given the positions of transmitter S and receiver R, calculate the distance r that the target echo will travel based on the speed of sound. R +r S The target T is determined to be located on the circumscribed ellipse (isochronous ellipse) with the transmitter S and receiver R as its foci;

[0012] Step 4: If the receiver R can determine the direction, the angle θ = ∠SRT between the target echo and the direct wave is obtained, and the target is located.

[0013] Step 5: If receiver R cannot find the direction, set up multiple receivers R. Transmitter S and receivers R at different locations form different circumscribed ellipses. The target T is located based on the coincidence point of the circumscribed ellipses of transmitter S and multiple receivers R.

[0014] Step 6: If a real-time link exists between the transmitter S and the receiver R, complete the full synchronization of spatiotemporal information and determine the time to complete the target T positioning;

[0015] Step 7: If there is no real-time link between transmitter S and receiver R, transmitter S encodes and modulates the waveform parameters, sound source location and transmission time and embeds them into the detection waveform and transmits them together. Receiver R obtains this information by demodulation and decoding, recovers the original transmitted waveform for echo detection, and uses the sound source spatiotemporal information to perform target localization calculation.

[0016] As a further aspect of the present invention: the direct wave is a moving waveform of transmitter S-receiver R; the target echo is a moving waveform of transmitter S-target T-receiver R.

[0017] As a further aspect of the present invention: In step 6, the application scenarios in which there is a real-time link between the transmitter S and the receiver R include fixed sonar systems and sonar systems on the same platform.

[0018] As a further aspect of the present invention: In step 7, the application scenarios in which there is no real-time link between the transmitter S and the receiver R include: between sonars of different ships in a surface ship formation, between sonars of surface ships and dipping sonars of shipborne anti-submarine helicopters, between dipping sonars of multiple anti-submarine helicopters, and between sonars of surface ships and receivers of airborne sonar buoy systems.

[0019] As a further aspect of the present invention: In step 7, the transmitter S obtains the transmission waveform parameters through sound source control, obtains the position information of the transmitter S and the time information of the sound source information emitted by the transmitter S through the external navigation system, encodes and modulates the transmission waveform parameters, time information and position information, obtains the detection waveform, and transmits it after power amplification.

[0020] As a further aspect of the present invention: In step 7, the receiver R receives the sound source information, completes pulse extraction after beamforming, and separates the waveform parameters, transmission time, and sound source position through demodulation and decoding. The target is located based on the waveform parameters, transmission time, and sound source position.

[0021] As a further aspect of the present invention: In step 7, the transmitter S transmits information using OFDM+QPSK modulation, including a start flag, waveform code, latitude of the transmitting sound source, longitude of the transmitting sound source, heading of the sound source, speed of the sound source, transmission time, and checksum.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses a communication-detection composite waveform. The transmitting end encodes and modulates the waveform parameters, sound source position and transmission time and embeds them into the detection waveform for transmission. The receiver obtains this information through demodulation and decoding, and at the same time recovers the original transmitted waveform for echo detection, and uses the sound source spatiotemporal information to perform target localization calculation. It does not rely on external communication links for sound source spatiotemporal information synchronization, so it has wide adaptability and can make full use of the sound pulses emitted by different sound sources in the formation for echo target detection. Attached Figure Description

[0023] Figure 1 A schematic diagram for target location.

[0024] Figure 2 This is a schematic diagram illustrating the principle of spatiotemporal information synchronization in a multi-base active sonar detection method.

[0025] Figure 3 This is a schematic diagram of a communication-detection composite waveform. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1 and Figure 2 A multi-base active sonar detection method, comprising:

[0028] Step 1: Transmitter S transmits sound source information;

[0029] Step 2: Receiver R receives the direct wave and the target echo;

[0030] Step 3: Given the positions of transmitter S and receiver R, calculate the distance r that the target echo will travel based on the speed of sound. R +r S The target T is determined to be located on the circumscribed ellipse (isochronous ellipse) with the transmitter S and receiver R as its foci;

[0031] Step 4: If the receiver R can determine the direction, the angle θ = ∠SRT between the target echo and the direct wave is obtained, and the target is located.

[0032] Step 5: If receiver R cannot find the direction, set up multiple receivers R. Transmitter S and receivers R at different locations form different circumscribed ellipses. The target T is located based on the coincidence point of the circumscribed ellipses of transmitter S and multiple receivers R.

[0033] Step 6: If a real-time link exists between the transmitter S and the receiver R, complete the full synchronization of spatiotemporal information and determine the time to complete the target T positioning;

[0034] Step 7: If there is no real-time link between transmitter S and receiver R, transmitter S encodes and modulates the waveform parameters, sound source location and transmission time and embeds them into the detection waveform and transmits them together. Receiver R obtains this information by demodulation and decoding, recovers the original transmitted waveform for echo detection, and uses the sound source spatiotemporal information to perform target localization calculation.

[0035] In this embodiment: Please refer to Figure 2 The direct wave is the moving waveform from transmitter S to receiver R; the target echo is the moving waveform from transmitter S to target T to receiver R.

[0036] The direct wave is the wave transmitted by transmitter S without refraction and sent to receiver R; the target echo is the wave transmitted by transmitter S after being refracted by target T and sent to receiver R.

[0037] In this embodiment: Please refer to Figure 2 In step 6: Application scenarios where there is a real-time link between the transmitter S and the receiver R include fixed sonar systems and sonar systems on the same platform.

[0038] In a fixed sonar system, the receiver and sound source remain in the same location after construction is completed, and they can be connected by wire (or processed by the same shore station); the sound source's transmission time and waveform parameters can be sent to the receiver in real time.

[0039] Platform-based sonar systems include, for example, a bistatic system consisting of a bow sonar and a towed sonar, a multistatic system consisting of an airborne dipping sonar and a sonar buoy, and an active source buoy and a passive sonar buoy. In these systems, the receiver and the transmitting source (remote control end) can communicate via a platform-to-device bus network to achieve time and parameter synchronization.

[0040] In this embodiment: Please refer to Figure 2 In step 7, the application scenarios where there is no real-time link between the transmitter S and the receiver R include: between sonars of different ships in a surface ship formation, between sonars of surface ships and dipping sonars of shipborne anti-submarine helicopters, between dipping sonars of multiple anti-submarine helicopters, and between sonars of surface ships and receivers of airborne sonar buoy systems.

[0041] In the above scenarios, the transmitting and receiving ends can communicate via wireless command data links. These links can exchange regional situational information such as platform positions, but they are not specifically designed for time synchronization. They typically employ transmission control strategies such as checksums and retransmissions, resulting in uncertain delays and making them difficult to use for time synchronization. Furthermore, sonar, being a sensor system, is traditionally located below the command and control system level. It lacks a direct interface with data links and navigation systems; communication must be relayed through the command and control system. Changing this involves coordinating interface relationships between different specialized vendors of the platform's mission systems, which is quite difficult.

[0042] When a sonar receiver is located on an underwater mobile platform (submarine, UUV, etc.), it cannot be synchronized with the transmitting sound source using an external wired or radio link.

[0043] In this embodiment: Please refer to Figure 2 In step 7, the transmitter S obtains the transmission waveform parameters through sound source control, obtains the position information of the transmitter S and the time information of the sound source information emitted by the transmitter S through the external navigation system, encodes and modulates the transmission waveform parameters, time information and position information, obtains the detection waveform, and transmits it after power amplification.

[0044] In this embodiment: Please refer to Figure 2 In step 7, the receiver R receives the sound source information, performs pulse extraction after beamforming, and separates the waveform parameters, transmission time, and sound source location through demodulation and decoding. Based on the waveform parameters, transmission time, and sound source location, the target is located.

[0045] In this embodiment: Please refer to Figure 2 and Figure 3 In step 7, the transmitter S sends out information using OFDM+QPSK modulation, including a start flag, waveform code, latitude of the transmitting sound source, longitude of the transmitting sound source, heading of the sound source, speed of the sound source, transmission time, and checksum.

[0046] The spatiotemporal data embedded in the emitted sound source waveform are shown in the table below:

[0047]

[0048]

[0049] The above data uses OFDM+QPSK modulation, with 80 data subcarriers, a subcarrier spacing of 3.125Hz, 128 IFFT points, an effective data part symbol time of 400ms, a cyclic prefix of 100ms, and an embedded waveform length of 500ms.

[0050] Figure 3The example is a communication-probe composite waveform, in which the embedded waveform is 500ms (consisting of the effective data part symbols and the cyclic prefix).

[0051] The location of transmitter S is determined by the latitude and longitude of the sound source; the time when transmitter S emits sound information is determined by the emission time; the transmitted waveform data is determined by the sound source heading and speed; and the transmitted waveform type is determined by the waveform code.

[0052] This invention does not rely on external communication links for sound source spatiotemporal information synchronization, thus it has wide adaptability and can make full use of the sound pulses emitted by different sound sources in the formation for echo target detection.

[0053] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0054] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-base active sonar detection method, characterized in that: This multi-base active sonar detection method includes: Step 1: Transmitter S transmits sound source information; Step 2: Receiver R receives the direct wave and the target echo; Step 3: Given the positions of transmitter S and receiver R, calculate the distance r that the target echo will travel based on the speed of sound. R +r S Determine whether the target T lies on the circumscribed ellipse with the transmitter S and receiver R as foci; Step 4: If the receiver R can determine the direction, the angle θ = ∠SRT between the target echo and the direct wave is obtained, and the target is located. Step 5: If receiver R cannot find the direction, set up multiple receivers R. Transmitter S and receivers R at different locations form different circumscribed ellipses. The target T is located based on the coincidence point of the circumscribed ellipses of transmitter S and multiple receivers R. Step 6: If a real-time link exists between the transmitter S and the receiver R, complete the full synchronization of spatiotemporal information and determine the time to complete the target T positioning; Step 7: If there is no real-time link between transmitter S and receiver R, transmitter S encodes and modulates the waveform parameters, sound source location and transmission time and embeds them into the detection waveform and transmits them together. Receiver R obtains this information by demodulation and decoding, recovers the original transmitted waveform for echo detection, and uses the sound source spatiotemporal information to perform target localization calculation.

2. The multi-base active sonar detection method according to claim 1, characterized in that, The direct wave is the moving waveform from transmitter S to receiver R; the target echo is the moving waveform from transmitter S to target T to receiver R.

3. The multi-base active sonar detection method according to claim 1, characterized in that, In step 6: Application scenarios where there is a real-time link between the transmitter S and the receiver R include fixed sonar systems and sonar systems on the same platform.

4. The multi-base active sonar detection method according to claim 1, characterized in that, In step 7, the application scenarios where there is no real-time link between the transmitter S and the receiver R include: between sonars of different ships in a surface ship formation, between sonars of surface ships and dipping sonars of shipborne anti-submarine helicopters, between dipping sonars of multiple anti-submarine helicopters, and between sonars of surface ships and receivers of airborne sonar buoy systems.

5. The multi-base active sonar detection method according to claim 1, characterized in that, In step 7, the transmitter S obtains the transmission waveform parameters through sound source control, and obtains the position information of the transmitter S and the time information of the sound source information emitted by the transmitter S through the external navigation system. The transmission waveform parameters, time information and position information are encoded and modulated to obtain the detection waveform, which is then transmitted after power amplification.

6. The multi-base active sonar detection method according to claim 1, characterized in that, In step 7, receiver R receives sound source information, performs pulse extraction after beamforming, and separates waveform parameters, transmission time, and sound source location through demodulation and decoding. Target localization is then completed based on the waveform parameters, transmission time, and sound source location.

7. The multi-base active sonar detection method according to any one of claims 1, 4, 5, and 6, characterized in that, In step 7, the transmitter S transmits information using OFDM+QPSK modulation, including a start flag, waveform code, latitude of the transmitting sound source, longitude of the transmitting sound source, heading of the sound source, speed of the sound source, transmission time, and checksum.

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