Ship identification system based on Beidou communication

Abstract

The invention provides a ship identification system based on Beidou communication, and relates to the technical field of ship identification, the ship identification system comprises a base station AIS unit, a processing unit and a Beidou communication unit, and the Beidou communication unit and the base station AIS unit are both connected with the processing unit; the base station AIS unit is used for collecting ship data, cleaning and enhancing the ship data to obtain AIS data, and transmitting the AIS data to the processing unit; the processing unit is used for carrying out subpackage processing on the AIS data to obtain subpackage data, carrying out packaging processing on each subpackage data to obtain packaging data, and transmitting the packaging data to the Beidou communication unit; the Beidou communication unit is used for being connected with a Beidou satellite, and the Beidou communication unit generates a ship message through the packed data and sends the ship message to the Beidou satellite. Through cleaning and enhancement of ship data, noise and interference are removed, and the accuracy of weak signal identification is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ship identification, and in particular to a ship identification system based on Beidou communication. Background Art

[0002] AIS is the abbreviation of Automatic Identification System, which is composed of shore-based (base station) facilities and ship-borne equipment. It is a digital navigation aid system and equipment that integrates network technology, modern communication technology, computer technology, and electronic information display technology. In the marine environment, the distance between adjacent base station AIS systems in the island and reef area is usually far, and the collection range cannot completely cover the island and reef area. The AIS system is limited by the communication distance and may not receive ship information in some areas within the island and reef area. In particular, when the ship is far away from the base station, the signal received by the AIS system is very weak, so that the ship information cannot be identified or may be incorrectly identified. Summary of the invention

[0003] The purpose of the present invention is to provide a ship identification system based on Beidou communication, and the technical problem to be solved is to improve the accuracy of weak signal recognition.

[0004] The present invention is achieved through the following technical solutions:

[0005] A ship identification system based on Beidou communication, comprising a base station AIS unit, a processing unit and a Beidou communication unit, wherein the Beidou communication unit and the base station AIS unit are both connected to the processing unit;

[0006] The base station AIS unit acquires the ship data, cleans and enhances the ship data to obtain AIS data, and the base station AIS unit transmits the AIS data to the processing unit;

[0007] The processing unit performs subpackaging processing on the AIS data to obtain subpackaging data, performs packetization processing on the subpackaging data to obtain packetized data, and the processing unit transmits the packetized data to the Beidou communication unit;

[0008] Among them, the above-mentioned Beidou communication unit is connected to the Beidou satellite, and the above-mentioned Beidou communication unit generates a ship message by assembling data, and sends the ship message to the Beidou satellite.

[0009] The above-mentioned base station AIS unit is responsible for collecting and cleaning ship data to obtain high-quality AIS data. AIS data contains key information such as the ship's position, heading, speed, etc., which is crucial for ship identification; by cleaning the ship data, noise and interference can be removed to improve the accuracy and reliability of AIS data; by enhancing the cleaned data, the clarity of the data is improved, and the accuracy and reliability of AIS data are further improved; by improving the accuracy and reliability of AIS data, the accuracy of weak signal identification is improved.

[0010] The above processing unit performs sub-packet processing and packet group processing on the AIS data. The sub-packet processing can divide a large amount of AIS data into smaller data packets for subsequent processing and transmission; the packet group processing is to reassemble the sub-packet data to form packet group data with a specific format and structure; this processing method can ensure the integrity and consistency of the data, while reducing bit errors and losses during data transmission.

[0011] The BeiDou communication unit generates ship messages from the packaged data and sends them to the BeiDou satellite. Using the BeiDou satellite communication function, the ship messages are transmitted to the designated location in real time and accurately, providing strong support for ship identification and monitoring.

[0012] Further, the base station AIS unit includes an AIS receiving link;

[0013] The AIS receiving link includes an AIS receiving antenna, a front-end filter and a low noise amplifier connected in sequence;

[0014] The above-mentioned AIS receiving antenna is used to receive ship signals;

[0015] The front-end filter is used to filter the ship signal, filter out the stray signal in the ship signal, and obtain the processed signal;

[0016] The low noise amplifier is used to amplify the processed signal to obtain an amplified processed signal.

[0017] The front-end filter performs filtering processing on the received ship signal. The function of the front-end filter is to filter out the stray signal in the ship signal, that is, to remove the interference components that do not belong to the target ship signal. Through filtering processing, a purer processing signal can be obtained, which provides a good foundation for subsequent signal amplification and recognition;

[0018] The above-mentioned low noise amplifier amplifies the processing signal. Since the ship signal may be attenuated during the transmission process, it is necessary to increase the amplitude of the signal through an amplifier to make it reach sufficient strength for subsequent processing and analysis.

[0019] Furthermore, the AIS receiving link further includes:

[0020] A power divider connected to the output end of the low noise amplifier;

[0021] The power divider is used to divide the amplified processed signal into two paths, thereby obtaining a one-path signal and a two-path signal.

[0022] The amplified processing signal is divided into two paths by a power divider. On the one hand, the parallel processing of the signal can be realized to improve the processing efficiency. This is especially important for the ship identification system with high real-time requirements, which can ensure that the system responds to and processes the received ship signals in time.

[0023] On the other hand, it helps to improve the reliability and stability of the system. During the signal transmission and processing process, due to the influence of various factors, signal loss or quality degradation may occur. By dividing the amplified and processed signal into two paths, even if one of the signals has problems, the other signal can still be used as a backup to ensure the normal operation of the system.

[0024] Furthermore, the AIS receiving link further includes:

[0025] A radio frequency module connected to the output end of the power divider;

[0026] The radio frequency module is used to convert the one-way signal and the two-way signal into a low intermediate frequency signal.

[0027] During the signal transmission and reception process of the above-mentioned RF module, the signal is often in a high-frequency state. It is difficult to directly process the high-frequency signal and it is easily affected by various interferences. Therefore, the RF module converts the one-way signal and the two-way signal from a high-frequency state to a low-intermediate-frequency state through specific circuits and algorithms, making subsequent signal processing and analysis more convenient and accurate. Through the conversion of the RF module, the signal can be effectively down-converted and filtered, high-frequency noise and interference components can be removed, and useful information of the signal can be retained, which helps to improve the signal-to-noise ratio of the signal and further enhance the recognition accuracy of weak signals.

[0028] Furthermore, the AIS receiving link further includes:

[0029] A demodulation module connected to the RF module and the processing unit;

[0030] The demodulation module is used to convert the low intermediate frequency signal into a data signal and transmit the data signal to the processing unit.

[0031] Since ship signals may be interfered by various factors during transmission, resulting in signal distortion or deformation, it is necessary to demodulate the low-intermediate frequency signal through the above-mentioned demodulation module to restore the original data signal; through demodulation processing, the modulation component in the signal can be removed and the baseband signal containing the ship information can be extracted. These baseband signals are then transmitted to the processing unit for further data processing and analysis.

[0032] Integrating the demodulation module into the AIS receiving link not only improves the demodulation accuracy and stability of the signal, but also makes the entire signal processing process more complete and efficient, helping to ensure that the ship identification system can accurately and quickly identify weak signals and improve the accuracy and reliability of ship identification.

[0033] Furthermore, the base station AIS unit further comprises a frequency synthesis module, and the frequency synthesis module is connected to the radio frequency module;

[0034] The frequency synthesis module is used to generate a local oscillator signal and transmit the local oscillator signal to the radio frequency module.

[0035] The main function of the above-mentioned frequency synthesis module is to generate a local oscillator signal and transmit the local oscillator signal to the RF module for use in the signal processing process; in the signal reception process, the local oscillator signal is used as a reference signal and mixed with the input signal to achieve the frequency conversion of the signal; for the ship identification system, since the ship signal may be in different frequency bands, it is necessary to be able to generate a stable and accurate local oscillator signal to support the frequency conversion processing of the signal.

[0036] Introducing the above-mentioned frequency synthesis module into the base station AIS unit can ensure that the RF module has a stable and accurate reference signal when processing ship signals; it helps to improve the accuracy and reliability of signal processing, especially when processing weak signals, and can reduce signal distortion and errors caused by frequency deviation.

[0037] In summary, the addition of the frequency synthesis module further improves the performance of the Beidou communication-based ship identification system in signal processing and identification. By providing a stable and accurate local oscillator signal, the accuracy and reliability of the RF module in processing ship signals are ensured, providing more powerful technical support for ship traffic safety and supervision.

[0038] Furthermore, the base station AIS unit also includes an AIS transmission link;

[0039] The AIS transmission link includes a modulation module, a power amplifier, an AIS signal filter and an AIS transmission antenna connected in sequence;

[0040] The modulation module is connected to the processing unit; the modulation module is used to receive the control signal sent by the processing unit and modulate the control signal to obtain a modulation signal;

[0041] The power amplifier is used to amplify the modulated signal to obtain an amplified modulated signal;

[0042] The AIS signal filter is used to filter out the spurious signal of the amplified modulated signal to obtain the transmission signal;

[0043] The AIS transmitting antenna is used to connect to the shipborne equipment and transmit the transmission signal to the shipborne equipment.

[0044] In the ship identification system based on Beidou communication, the base station AIS unit not only has the function of receiving ship signals, but also adds an AIS transmission link to achieve two-way communication with shipborne equipment. The above-mentioned modulation module is connected to the processing unit as the starting point of the transmission link. It is responsible for receiving the control signals sent by the processing unit, which contain the instructions and data required to communicate with the shipborne equipment; the modulation module converts the control signal into a modulation signal suitable for transmission according to the predetermined modulation method.

[0045] The above-mentioned power amplifier amplifies the modulated signal; since the signal may be attenuated during the transmission process, it is necessary to increase the power of the signal through the power amplifier to ensure that the signal can cover a sufficient range and be successfully transmitted to the shipboard equipment.

[0046] The amplified signal may contain some spurious signals, which will interfere with the normal transmission of the signal. Therefore, the AIS signal filter is introduced into the transmission link to filter out these spurious signals and ensure the purity of the transmission signal.

[0047] The AIS transmitting antenna is responsible for transmitting the transmission signal to the shipboard equipment. The AIS transmitting antenna converts the transmission signal into electromagnetic waves and propagates it to the shipboard equipment through the air medium; after the shipboard equipment receives the signal, it can decode and process it to achieve communication with the base station AIS unit.

[0048] Furthermore, the base station AIS unit further includes a temperature compensated crystal oscillator, and the temperature compensated crystal oscillator is connected to the frequency synthesis module, the modulation module and the processing unit.

[0049] The function of the temperature compensated crystal oscillator mentioned above is mainly to provide a high-precision and high-stability clock signal. Since the working environment of the ship identification system may face large temperature changes, the traditional quartz crystal oscillator may cause frequency instability due to temperature drift. The temperature compensated crystal oscillator can automatically adjust the oscillation frequency through the built-in temperature compensation circuit, thereby eliminating the impact of temperature changes on frequency stability.

[0050] The high-precision clock signal of the temperature-compensated crystal oscillator mentioned above is essential for the normal operation of the frequency synthesis module, modulation module and processing unit. The frequency synthesis module requires a stable reference signal to generate the local oscillator signal, and the temperature-compensated crystal oscillator provides such a signal; at the same time, the modulation module also requires an accurate clock signal to ensure the accuracy of the modulation process when processing the control signal; in addition, the processing unit also requires a stable clock signal as a reference when performing data processing and calculations; therefore, the base station AIS unit not only improves the signal stability by introducing a temperature-compensated crystal oscillator, but also ensures the coordinated work between the various modules of the entire system; it helps to improve the recognition accuracy, communication efficiency and reliability of the ship identification system.

[0051] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0052] The above-mentioned base station AIS unit is responsible for collecting and cleaning ship data to obtain high-quality AIS data. AIS data contains key information such as the ship's position, heading, speed, etc., which is crucial for ship identification; by cleaning the ship data, noise and interference can be removed to improve the accuracy and reliability of AIS data; by enhancing the cleaned data, the clarity of the data is improved, and the accuracy and reliability of AIS data are further improved; by improving the accuracy and reliability of AIS data, the accuracy of weak signal identification is improved.

[0053] The above processing unit performs sub-packet processing and packet group processing on the AIS data. The sub-packet processing can divide a large amount of AIS data into smaller data packets for subsequent processing and transmission; the packet group processing is to reassemble the sub-packet data to form packet group data with a specific format and structure; this processing method can ensure the integrity and consistency of the data, while reducing bit errors and losses during data transmission.

[0054] The BeiDou communication unit generates ship messages from the packaged data and sends them to the BeiDou satellite. Using the BeiDou satellite communication function, the ship messages are transmitted to the designated location in real time and accurately, providing strong support for ship identification and monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0056] Figure 1 This is the system block diagram.

[0057] Marks and corresponding parts names in the attached drawings:

[0058] 100, base station AIS unit; 101, AIS receiving antenna; 102, front-end filter; 103, low noise amplifier; 104, power divider; 105, RF module; 106, demodulation module; 110, AIS receiving link; 120, AIS transmitting link; 121, AIS signal filter; 122, AIS transmitting antenna; 123, power amplifier; 124, modulation module; 130, temperature compensated crystal oscillator; 140, frequency synthesis module; 200, processing unit; 300, Beidou communication unit. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0060] Example 1

[0061] Combination Figure 1 , this embodiment 1 provides a ship identification system based on Beidou communication, including a base station AIS unit 100, a processing unit 200 and a Beidou communication unit 300, and the Beidou communication unit 300 and the base station AIS unit 100 are both connected to the processing unit 200;

[0062] The base station AIS unit 100 is used to collect ship data, clean and enhance the ship data to obtain AIS data, and transmit the AIS data to the processing unit 200;

[0063] The processing unit 200 is used to first perform sub-packaging processing on the AIS data to obtain sub-packaging data, then perform grouping processing on each sub-packaging data to obtain grouped data, and transmit the grouped data to the Beidou communication unit 300;

[0064] The above-mentioned Beidou communication unit 300 includes a Beidou communication module, a Beidou receiving antenna and a Beidou transmitting antenna. The above-mentioned Beidou receiving antenna and Beidou transmitting antenna are both connected to the Beidou communication module. The above-mentioned Beidou receiving antenna and Beidou transmitting antenna are used to interact with Beidou satellites for information; the above-mentioned Beidou communication module is used to generate ship messages by packaging data, and send the ship messages to Beidou satellites through the Beidou transmitting antenna.

[0065] The processing unit 200 is also connected to a storage device for storing data sent to the Beidou satellite.

[0066] The base station AIS unit 100 is responsible for collecting and cleaning ship data to obtain high-quality AIS data. The AIS data contains key information such as the ship's position, heading, speed, etc., which is crucial for ship identification. By cleaning the ship data, noise and interference can be removed to improve the accuracy and reliability of the AIS data. By enhancing the cleaned data, the clarity of the data is improved, and the accuracy and reliability of the AIS data are further improved. By improving the accuracy and reliability of the AIS data, the accuracy of weak signal identification is improved.

[0067] The processing unit 200 performs sub-packet processing and packet group processing on the AIS data. The sub-packet processing can divide a large amount of AIS data into smaller data packets for subsequent processing and transmission; the packet group processing is to reassemble the sub-packet data to form packet group data with a specific format and structure; this processing method can ensure the integrity and consistency of the data, while reducing bit errors and losses during data transmission.

[0068] The Beidou communication unit 300 generates a ship message from the packaged data and sends it to the Beidou satellite. By using the Beidou satellite communication function, the ship message is transmitted to the designated location in real time and accurately, providing strong support for ship identification and monitoring.

[0069] Example 2

[0070] Based on the embodiment 1, the base station AIS unit 100 comprises an AIS receiving link 110;

[0071] The AIS receiving link 110 comprises an AIS receiving antenna 101, a front-end filter 102 and a low noise amplifier 103 connected in sequence;

[0072] The AIS receiving antenna 101 is used to receive ship signals;

[0073] The front-end filter 102 is used to filter the ship signal, filter out the stray signal in the ship signal, and obtain a processed signal;

[0074] The low noise amplifier 103 is used to amplify the processed signal to obtain an amplified processed signal.

[0075] The front-end filter 102 performs filtering processing on the received ship signal. The function of the front-end filter 102 is to filter out the stray signal in the ship signal, that is, to remove the interference components that do not belong to the target ship signal. Through filtering processing, a purer processing signal can be obtained, which provides a good foundation for subsequent signal amplification and recognition;

[0076] The low noise amplifier 103 amplifies the processed signal. The low noise amplifier 103 aims to amplify the signal while minimizing the introduced noise, thereby maintaining the signal-to-noise ratio, which is particularly important for the identification of weak signals. Since the ship signal may be attenuated during the transmission process, an amplifier is required to increase the amplitude of the signal to achieve sufficient strength for subsequent processing and analysis.

[0077] Example 3

[0078] Based on Embodiment 2, the AIS receiving link 110 further includes:

[0079] A power divider 104 connected to the output end of the low noise amplifier 103;

[0080] The power divider 104 is used to divide the amplified signal into two paths, thereby obtaining a one-path signal and a two-path signal.

[0081] The amplified processed signal is divided into two paths by the power divider 104. On the one hand, the parallel processing of the signal can be realized to improve the processing efficiency; this is particularly important for the ship identification system with high real-time requirements, which can ensure that the system responds to and processes the received ship signal in time;

[0082] On the other hand, it helps to improve the reliability and stability of the system. During the signal transmission and processing process, due to the influence of various factors, signal loss or quality degradation may occur. By dividing the amplified and processed signal into two paths, even if one of the signals has problems, the other signal can still be used as a backup to ensure the normal operation of the system;

[0083] In addition, the introduction of the power divider 104 can also provide more flexibility for subsequent signal analysis and processing; according to actual needs, different processing and analysis can be performed on the one-way signal and the two-way signal to extract more information or achieve specific functions. For example, spectrum analysis can be performed on the one-way signal and time domain analysis can be performed on the two-way signal, so as to more comprehensively understand the characteristics and status of the ship signal.

[0084] Example 4

[0085] Based on Embodiment 3, the AIS receiving link 110 further includes:

[0086] A radio frequency module 105 connected to the output end of the power divider 104;

[0087] The radio frequency module 105 is used to convert the one-way signal and the two-way signal into a low intermediate frequency signal.

[0088] During the signal transmission and reception process of the above-mentioned RF module 105, the signal is often in a high-frequency state. It is difficult to directly process the high-frequency signal and it is easily affected by various interferences. Therefore, the RF module 105 converts the one-way signal and the two-way signal from a high-frequency state to a low-intermediate-frequency state through specific circuits and algorithms, making subsequent signal processing and analysis more convenient and accurate; through the conversion of the RF module 105, it is possible to achieve effective frequency reduction and filtering of the signal, remove high-frequency noise and interference components, retain useful information of the signal, help improve the signal-to-noise ratio of the signal, and further enhance the recognition accuracy of weak signals.

[0089] Example 5

[0090] On the basis of Embodiment 4, the AIS receiving link 110 further includes a demodulation module 106, and the demodulation module 106 is connected to the RF module 105 and the processing unit 200;

[0091] The demodulation module 106 is used to convert the low intermediate frequency signal into a data signal and transmit the data signal to the processing unit 200 .

[0092] The above demodulation is one of the important links in signal processing, especially in applications such as ship identification, accurate demodulation of weak signals is particularly important. Since ship signals may be interfered by various factors during transmission, resulting in signal distortion or deformation, it is necessary to demodulate the low intermediate frequency signal through the above demodulation module 106 to restore the original data signal; through demodulation processing, the modulation component in the signal can be removed and the baseband signal containing the ship information can be extracted, and these baseband signals are then transmitted to the processing unit 200 for further data processing and analysis.

[0093] The demodulation module 106 generally adopts a specific demodulation algorithm and technology to accurately demodulate the characteristics and format of the ship signal. Integrating the demodulation module 106 into the AIS receiving link 110 not only improves the demodulation accuracy and stability of the signal, but also makes the entire signal processing process more complete and efficient, which helps to ensure that the ship identification system can accurately and quickly identify weak signals and improve the accuracy and reliability of ship identification.

[0094] Example 6

[0095] On the basis of Embodiment 4 or Embodiment 5, the base station AIS unit 100 further includes a frequency synthesis module 140, and the frequency synthesis module 140 is connected to the radio frequency module 105;

[0096] The frequency synthesis module 140 is used to generate a local oscillation signal and transmit the local oscillation signal to the RF module 105 .

[0097] The main function of the above-mentioned frequency synthesis module 140 is to generate a local oscillator signal and transmit the local oscillator signal to the RF module 105 for use in the signal processing process; in the signal reception process, the local oscillator signal is used as a reference signal and mixed with the input signal to achieve the frequency conversion of the signal; for the ship identification system, since the ship signal may be in different frequency bands, it is necessary to be able to generate a stable and accurate local oscillator signal to support the frequency conversion processing of the signal.

[0098] The frequency synthesis module 140 adopts advanced frequency synthesis technology and can generate local oscillator signals of different frequencies as required. It usually includes one or more oscillators, frequency dividers, mixers and other components, and can output stable and continuous local oscillator signals by accurately controlling the working status of these components.

[0099] Introducing the above-mentioned frequency synthesis module 140 into the base station AIS unit 100 can ensure that the RF module 105 has a stable and accurate reference signal when processing ship signals; it helps to improve the accuracy and reliability of signal processing, especially when processing weak signals, and can reduce signal distortion and errors caused by frequency deviation.

[0100] In summary, the addition of the frequency synthesis module 140 further improves the performance of the Beidou communication-based ship identification system in signal processing and identification. By providing a stable and accurate local oscillator signal, the accuracy and reliability of the RF module 105 in processing ship signals are ensured, providing more powerful technical support for ship traffic safety and supervision.

[0101] Example 7

[0102] Based on Embodiment 6, the base station AIS unit 100 further includes an AIS transmission link 120;

[0103] The AIS transmission link 120 includes a modulation module 124, a power amplifier 123, an AIS signal filter 121 and an AIS transmission antenna 122 connected in sequence;

[0104] The modulation module 124 is connected to the processing unit 200; the modulation module 124 is used to receive the control signal sent by the processing unit 200, and modulate the control signal to obtain a modulated signal;

[0105] The power amplifier 123 is used to amplify the modulated signal to obtain an amplified modulated signal;

[0106] The AIS signal filter 121 is used to filter out the spurious signal of the amplified modulated signal to obtain the transmission signal;

[0107] The AIS transmitting antenna 122 is used to connect to the shipborne equipment and transmit the transmission signal to the shipborne equipment.

[0108] In the ship identification system based on Beidou communication, the base station AIS unit 100 not only has the function of receiving ship signals, but also adds an AIS transmission link 120 to achieve two-way communication with shipborne equipment. The design of the AIS transmission link 120 fully considers the key links such as signal modulation, amplification, filtering and transmission to ensure that the signal can be accurately and stably transmitted to the shipborne equipment.

[0109] The modulation module 124 is connected to the processing unit 200 as the starting point of the transmission link. It is responsible for receiving the control signals sent by the processing unit 200, which contain the instructions and data required to communicate with the shipborne equipment; the modulation module 124 converts the control signals into modulation signals suitable for transmission according to the predetermined modulation mode.

[0110] The power amplifier 123 amplifies the modulated signal; since the signal may be attenuated during the transmission process, it is necessary to increase the power of the signal through the power amplifier 123 to ensure that the signal can cover a sufficient range and be successfully transmitted to the shipboard equipment.

[0111] The amplified signal may contain some spurious signals, which may interfere with the normal transmission of the signal. Therefore, the AIS signal filter 121 is introduced into the transmission link to filter out these spurious signals and ensure the purity of the transmission signal.

[0112] The AIS transmitting antenna 122 is responsible for transmitting the transmission signal to the shipboard equipment. The AIS transmitting antenna 122 converts the transmission signal into electromagnetic waves and transmits it to the shipboard equipment through the air medium; after receiving the signal, the shipboard equipment can decode and process it, thereby realizing communication with the base station AIS unit 100.

[0113] Example 8

[0114] On the basis of Embodiment 7, the base station AIS unit 100 further includes a temperature compensated crystal oscillator 130 , and the temperature compensated crystal oscillator 130 is connected to the frequency synthesis module 140 , the modulation module 124 and the processing unit 200 .

[0115] The function of the temperature compensated crystal oscillator 130 is mainly to provide a high-precision and high-stability clock signal. Since the working environment of the ship identification system may face large temperature changes, the traditional quartz crystal oscillator may cause frequency instability due to temperature drift. The temperature compensated crystal oscillator 130 can automatically adjust the oscillation frequency through the built-in temperature compensation circuit, thereby eliminating the influence of temperature changes on frequency stability.

[0116] The high-precision clock signal of the temperature-compensated crystal oscillator 130 is essential for the normal operation of the frequency synthesis module 140, the modulation module 124 and the processing unit 200. The frequency synthesis module 140 requires a stable reference signal to generate a local oscillator signal, and the temperature-compensated crystal oscillator 130 provides such a signal; at the same time, the modulation module 124 also requires an accurate clock signal to ensure the accuracy of the modulation process when processing the control signal; in addition, the processing unit 200 also requires a stable clock signal as a reference when performing data processing and calculations; therefore, the base station AIS unit 100 not only improves the signal stability by introducing the temperature-compensated crystal oscillator 130, but also ensures the coordinated work between the various modules of the entire system; it helps to improve the recognition accuracy, communication efficiency and reliability of the ship identification system.

[0117] Exemplarily, the AIS receiving antenna 101 and the AIS transmitting antenna 122 use AIS transceiver antennas, the two RF modules 105 are respectively an AIS-A RF channel module and an AIS-B RF channel module, the demodulation module 106 is a GMSK demodulation module, the modulation module 124 is a GMSK modulation module, and the temperature compensated crystal oscillator 130 is a 19.2 MHzw temperature compensated crystal oscillator; the specific working process is as follows:

[0118] When the shipborne equipment is far away from the base station, the AIS transceiver antenna receives the ship signal (the ship signal is weak at this time). After the ship signal passes through the front-end filter 102, the out-of-band spurious signal is filtered out, and then amplified in the low noise amplifier 103. The power divider 104 divides the amplified signal into two paths, which enter the AIS-A radio frequency channel module and the AIS-B radio frequency channel module respectively to obtain a low intermediate frequency signal, which is restored to a data signal in the GMSK demodulation module 106, and the processing module makes a corresponding response according to the received data signal.

[0119] The base station AIS unit 100 uses a 19.2MHz temperature-compensated crystal oscillator as the working clock of the entire system, providing a reference source for the frequency synthesis module 140, the GMSK modulation module and the processing unit 200. The frequency synthesis module 140 provides the required local oscillator signal for the AIS-A radio frequency channel module and the AIS-B radio frequency channel module.

[0120] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A ship identification system based on Beidou communication, characterized in that: It comprises a base station AIS unit (100), a processing unit (200) and a Beidou communication unit (300), wherein the Beidou communication unit (300) and the base station AIS unit (100) are both connected to the processing unit (200); The base station AIS unit (100) acquires ship data, cleans and enhances the ship data to obtain AIS data, and the base station AIS unit (100) transmits the AIS data to the processing unit (200); The processing unit (200) performs subpackaging processing on the AIS data to obtain subpackaging data, performs grouping processing on the subpackaging data to obtain grouped data, and the processing unit (200) transmits the grouped data to the Beidou communication unit (300); The Beidou communication unit (300) is connected to a Beidou satellite, and the Beidou communication unit (300) generates a ship message from the packaged data, and sends the ship message to the Beidou satellite.

2. A ship identification system based on Beidou communication according to claim 1, characterized in that: The base station AIS unit (100) comprises an AIS receiving link (110); The AIS receiving link (110) comprises an AIS receiving antenna (101), a front-end filter (102) and a low noise amplifier (103) connected in sequence; The AIS receiving antenna (101) is used to receive ship signals; The front-end filter (102) is used to filter the ship signal, filter out the stray signal in the ship signal, and obtain a processed signal; The low noise amplifier (103) is used to amplify the processed signal to obtain an amplified processed signal.

3. A ship identification system based on Beidou communication according to claim 2, characterized in that: The AIS receiving link (110) further comprises: A power divider (104) is connected to the output end of the low noise amplifier (103); the power divider (104) is used to divide the amplified processed signal into two paths, thereby obtaining a one-path signal and a two-path signal.

4. A ship identification system based on Beidou communication according to claim 3, characterized in that: The AIS receiving link (110) further comprises: A radio frequency module (105), the radio frequency module (105) being connected to the output end of the power divider (104); the radio frequency module (105) being used to convert the one-way signal and the two-way signal into low intermediate frequency signals.

5. A ship identification system based on Beidou communication according to claim 4, characterized in that: The AIS receiving link (110) further comprises: A demodulation module (106) connected to the radio frequency module (105) and the processing unit (200); The demodulation module (106) is used to convert the low intermediate frequency signal into a data signal, and transmit the data signal to the processing unit (200).

6. A ship identification system based on Beidou communication according to claim 4 or 5, characterized in that: The base station AIS unit (100) further comprises a frequency synthesis module (140), wherein the frequency synthesis module (140) is connected to the radio frequency module (105); The frequency synthesis module (140) is used to generate a local oscillation signal and transmit the local oscillation signal to the radio frequency module (105).

7. A ship identification system based on Beidou communication according to claim 6, characterized in that: The base station AIS unit (100) further comprises an AIS transmission link (120); The AIS transmission link (120) comprises a modulation module (124), a power amplifier (123), an AIS signal filter (121) and an AIS transmission antenna (122) which are connected in sequence; The modulation module (124) is connected to the processing unit (200); the modulation module (124) is used to receive a control signal sent by the processing unit (200), and modulate the control signal to obtain a modulation signal; The power amplifier (123) is used to amplify the modulated signal to obtain an amplified modulated signal; The AIS signal filter (121) is used to filter out the stray signal of the amplified modulated signal to obtain a transmission signal; The AIS transmitting antenna (122) is used to connect to the shipborne equipment and transmit the transmission signal to the shipborne equipment.

8. A ship identification system based on Beidou communication according to claim 7, characterized in that: The base station AIS unit (100) further comprises a temperature-compensated crystal oscillator (130), wherein the temperature-compensated crystal oscillator (130) is connected to a frequency synthesis module (140), a modulation module (124) and a processing unit (200).

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