Chaotic synchronization information security protection system and method based on Beidou receiver time service

Abstract

The invention discloses a chaos synchronization information security protection system and method based on Beidou receiver time service, and the system comprises a transmitting end which enables a chaos source to generate a noise-like narrow-band chaos signal through filtering sampling and high-precision clock driving of a Beidou time service unit, enables a service signal to be superposed with the narrow-band chaos signal, and enables the service signal to be transmitted to a receiving end; chaos carrier frequency mixing superposition signals are obtained; the scattering channel is used for transmitting the chaotic carrier mixing superposed signal; and a receiving end obtains a synchronous narrow-band chaotic signal by adopting a chaotic source and a filtering sampling unit which have the same parameters as the transmitting end and being driven by a high-precision synchronous clock output by a Beidou time service unit, and then performs subtraction operation on a chaotic carrier mixing superposed signal transmitted by the transmitting end and the narrow-band chaotic signal to recover an original service signal. Accurate clock synchronization of the receiving end and the transmitting end is achieved through the Beidou time service unit, stable chaotic signals high in anti-noise capacity are obtained through the filtering and sampling unit, and long-distance and high-safety information transmission is achieved.

Description

Technical Field

[0001] This invention belongs to the field of information security protection technology, specifically relating to a chaotic synchronization information security protection system and method based on Beidou receiver timing. Background Technology

[0002] In today's information age, the requirements for the security and stability of information transmission are becoming increasingly stringent. Chaotic encrypted communication is highly compatible with the needs of "difficult to crack" and "signal concealment". Utilizing chaotic phenomena to achieve difficult-to-crack information transmission and addressing the increasingly complex information security needs has become a research hotspot in recent years.

[0003] However, precise clock synchronization between the transmitter and receiver in traditional chaotic systems is difficult. Even slight frequency drift or phase deviation can lead to decryption failure. Furthermore, the physical implementation of chaotic oscillations is susceptible to hardware noise, resulting in signal distortion. For example, invention patent CN118784207A discloses a dynamic encrypted secure communication system device and method based on multi-longitudinal-mode chaotic synchronization. The device includes a chaotic signal generation module, an information encryption module, an optical fiber transmission module, a chaotic signal synchronization module, and an information decryption module. In the chaotic signal generation module, a broadband noise-driven Fabry-Perot laser generates chaotic signals with multiple longitudinal modes. These chaotic signals, with arbitrary combinations of longitudinal modes, encrypt user information across different cores of a seven-core optical fiber, increasing the system's key space. In the information encryption module, confidential information from different users on the seven-core optical fiber is first scrambled in intensity by a dispersive element, and then the chaotic signals with different combinations of longitudinal modes perform phase encryption on the confidential information, achieving two-dimensional encryption of the confidential signal in both intensity and phase. Simultaneously, spatial division multiplexing technology effectively improves the communication capacity of the secure communication system. The above scheme also suffers from difficulties in accurately synchronizing the clocks of the transmitting and receiving ends, and its direct application of chaotic source signals for information encryption results in poor stability.

[0004] Therefore, it is necessary to propose a chaotic synchronization system for BeiDou receiver time synchronization to solve the problems of high-precision synchronization of transceiver clocks and poor stability of the system during long-term operation in current chaotic communication. Summary of the Invention

[0005] The purpose of this invention is to provide a chaotic synchronization information security protection system and method based on BeiDou receiver timing. It utilizes a BeiDou timing receiver to obtain time information by receiving BeiDou satellite signals, ensuring the accuracy of the time reference at the transmitting and receiving ends; and processes the chaotic source through a filtering and sampling module to obtain a digital random sequence, which is then driven by a clock signal and processed by digital-to-analog conversion to obtain a stable chaotic signal with strong noise resistance, enabling long-distance and highly secure information transmission.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] Firstly, a chaotic synchronization information security protection system based on BeiDou receiver timing is provided, comprising a transmitter, a scattering channel, and a receiver connected in sequence.

[0008] The transmitting end generates a high-performance ultra-wideband chaotic source based on the photoelectric feedback loop. Through filtering, sampling, digital-to-analog conversion, and high-precision clock output from the Beidou timing unit, it generates a noise-like narrowband chaotic signal. The service signal is then superimposed with the narrowband chaotic signal to obtain a chaotic carrier mixing superposition signal, thereby encrypting the transmitted information.

[0009] The scattering channel is used to establish a stable transmission link between the transceiver and the receiver, and to transmit the chaotic carrier mixing and superimposed signal to the receiver.

[0010] The receiving end obtains a digital random sequence by using a chaotic source and a filtering sampling unit with the same parameters as the transmitting end, and obtains a synchronized narrowband chaotic signal under the drive of a high-precision synchronous clock output by the Beidou timing unit. Then, it performs a subtraction operation between the chaotic carrier mixing and superposition signal transmitted by the transmitting end and the narrowband chaotic signal to recover the original service signal.

[0011] Preferably, the transmitting end includes a chaos source unit, a filtering and sampling unit, a BeiDou timing unit, a clock unit, a chaotic signal generation unit, a service signal input unit, an attenuator unit, and a signal aliasing unit;

[0012] The output port of the chaotic source unit is connected to the input port of the filtering sampling unit, the output port of the BeiDou timing unit is connected to the input port of the clock unit, the output port of the filtering sampling unit is connected to the chaotic signal input port of the chaotic signal generation unit, the output port of the clock unit is connected to the clock input port of the chaotic signal generation unit, the output port of the service signal input unit is connected to the input port of the attenuator unit, the output ports of both the chaotic signal generation unit and the attenuator unit are connected to the input port of the signal aliasing unit, and the output port of the signal aliasing unit is connected to the scattering channel.

[0013] Preferably, the receiving end includes a chaos source unit, a filtering and sampling unit, a BeiDou time synchronization unit, a clock unit, a chaos signal generation unit, a signal extraction unit, and a service signal output unit;

[0014] The output port of the chaotic source unit is connected to the input port of the filtering sampling unit, the output port of the Beidou timing unit is connected to the input port of the clock unit, the output ports of the filtering sampling unit and the clock unit are both connected to the clock input port of the chaotic signal generation unit, the output port of the chaotic signal generation unit is connected to the input port of the signal extraction unit, the input port of the signal extraction unit is also connected to the scattering channel, and the output port of the signal extraction unit is connected to the input port of the service signal output unit.

[0015] Preferably, the chaotic source unit at the transmitting end and the chaotic source unit at the receiving end are the same, both of which are provided by a laser and input into a photoelectric feedback loop composed of a Mach-Zehnder intensity modulator, an optical fiber delay line, a photodetector, and a radio frequency amplifier. The signal in the loop continuously undergoes a cycle of "nonlinear modulation-feedback superposition-remodulation", and finally outputs a quasi-random, unpredictable broadband chaotic signal. Finally, a digital random sequence is obtained by filtering and sampling the chaotic signal.

[0016] Secondly, a method for protecting the security of chaotic synchronization information based on BeiDou receiver timing is provided, including the following steps:

[0017] S1. At the transmitting end, the broadband chaotic source generates a digital random sequence after filtering and sampling. Driven by the clock output by the Beidou timing unit, and after digital-to-analog conversion processing by the chaotic signal generation unit, a noise-like narrowband chaotic signal is generated. The low-amplitude service signal attenuated by the attenuator is mixed and encrypted with the narrowband chaotic signal in the signal mixing unit to obtain a chaotic carrier mixing superimposed signal, thereby realizing the secure transmission of the signal.

[0018] S2, the scattering channel, securely and with low distortion transmits the chaotic carrier mixing and superposition signal encrypted by the transmitter to the receiver.

[0019] S3. The receiving end obtains a digital random sequence by using a chaotic source and a filtering sampling unit with the same parameters as the transmitting end, and obtains a narrowband chaotic signal synchronized with the transmitting end under the high-precision synchronous clock output by the Beidou timing unit. Then, the chaotic carrier mixing and superposition signal transmitted by the transmitting end and the narrowband chaotic signal of the receiving end are subtracted in the signal extraction unit to cancel out the chaotic carrier and recover the original service signal.

[0020] Preferably, in step S1, a laser provides the light source, which is input into a photoelectric feedback loop consisting of a Mach-Zehnder intensity modulator, an optical fiber delay line, a photodetector, and a radio frequency amplifier. The signal within the loop continuously undergoes a cycle of "nonlinear modulation-feedback superposition-remodulation," ultimately outputting a quasi-random, unpredictable broadband chaotic signal. A digital random sequence is obtained by filtering and sampling the broadband chaotic signal. The BeiDou timing unit receives the clock signal from the BeiDou satellite. Driven by the 10MHz clock signal output by the BeiDou timing unit, the digital random sequence is converted from digital to analog by the chaotic signal generation unit to generate a noise-like narrowband chaotic signal. The service signal to be transmitted is then attenuated and superimposed with the narrowband chaotic signal to obtain a chaotic carrier mixing superposition signal, thereby achieving signal encryption.

[0021] Preferably, in step S3, the same broadband chaotic signal is obtained by using devices with parameters consistent with those of the transmitting end, and a digital random sequence is obtained after filtering and sampling. The BeiDou timing unit receives the precise clock signal from the BeiDou satellite, and synchronizes the clocks of the transmitting and receiving ends through clock discipline technology. The digital random sequence is processed by the digital-to-analog conversion of the signal generation unit under clock drive to obtain a synchronized narrowband chaotic signal. Finally, the signal is subtracted from the chaotic carrier mixing and superposition signal transmitted by the transmitting end to recover the service signal.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. This invention utilizes a Beidou time receiver to provide a precise and stable clock for the transceiver end of a chaotic system, ensuring the uniformity of the time base between the transceiver end and providing a basis for obtaining synchronized chaotic signals for correct decryption; thus solving the problem of difficulty in high-precision clock synchronization in existing chaotic communication, which leads to signal deviation between the transceiver end.

[0024] 2. This invention generates narrowband chaotic signals by filtering and sampling the chaotic source and performing digital-to-analog conversion, thereby improving the anti-interference capability of the chaotic signals. The system exhibits good stability during long-term operation and can achieve long-distance, high-security information transmission. Furthermore, due to the high anti-interference capability of the chaotic signals, they can be directly transmitted in traditional channels with limited bandwidth, such as microwave and radio frequency channels. This solves the problem that existing chaotic signals have weak anti-interference capabilities and cannot be directly transmitted in traditional channels with limited bandwidth, such as microwave and radio frequency channels.

[0025] 3. The present invention has a simple structure, is easy to build, and is convenient for engineering applications. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a chaotic synchronization information security protection system based on Beidou receiver timing according to the present invention. In the diagram, solid lines represent optical signal connections, and dashed lines represent clock signal connections.

[0027] Figure 2 is a schematic diagram of broadband chaotic signal generation. In the figure, solid lines represent electrical signal connections, and dashed lines represent optical signal connections.

[0028] Figure 3 This is a flowchart of a method for protecting the security of chaotic synchronization information based on BeiDou receiver timing, according to the present invention.

[0029] Figure 4 The waveform diagram shows the chaotic signals and desynchronization between the transmitting and receiving ends because the clock signals are not synchronized by the Beidou receiver.

[0030] Figure 5 for Figure 4 The waveform diagram shows that, under certain circumstances, clock asynchrony can cause irreversible deviations in the chaotic trajectories of the transmitting and receiving ends.

[0031] Figure 6 To achieve time synchronization using a BeiDou receiver, the clock signal source is the satellite-based atomic clock. The system relies on ground-to-ground time synchronization, and the terminal relies on local real-time discipline. The clock signal can achieve nanosecond-level stability, resulting in the waveform diagram for system synchronization.

[0032] Figure 7 for Figure 6 When the clock signals are synchronized, the chaotic sequences at the transmitting and receiving ends are synchronized, and the waveform diagram shows the alignment of the two chaotic signals. Detailed Implementation

[0033] To make the objectives and advantages of the present invention clearer, embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] like Figure 1 , 2 As shown, the present invention is a chaotic synchronization information security protection system based on Beidou receiver timing, comprising a transmitter, a scattering channel and a receiver connected in sequence.

[0035] The transmitting end generates a high-performance ultra-wideband chaotic source based on the photoelectric feedback loop. This source is then filtered, sampled, converted from digital to analog, and driven by a high-precision clock output from the BeiDou timing unit to produce a noise-like narrowband chaotic signal. The service signal is then superimposed on this narrowband chaotic signal to obtain a chaotic carrier mixing superposition signal, thereby encrypting the transmitted information.

[0036] The scattering channel establishes a stable transmission link between the transceiver and receiver, enabling the chaotic carrier mixing and superposition signal to be transmitted to the receiver safely and with low distortion.

[0037] The receiving end obtains a digital random sequence by using a chaotic source and a filtering sampling unit with the same parameters as the transmitting end, and obtains a synchronized narrowband chaotic signal under the drive of a high-precision synchronous clock output by the Beidou timing unit. Then, it performs a subtraction operation between the chaotic carrier mixing and superposition signal transmitted by the transmitting end and the narrowband chaotic signal to recover the original service signal.

[0038] The transmitting end includes a chaotic source unit, a filtering and sampling unit, a BeiDou timing unit, a clock unit, a chaotic signal generation unit, a service signal input unit, an attenuator unit, and a signal aliasing unit. The output port of the chaotic source unit is connected to the input port of the filtering and sampling unit; the output port of the BeiDou timing unit is connected to the input port of the clock unit; the output port of the filtering and sampling unit is connected to the chaotic signal input port of the chaotic signal generation unit; the output port of the clock unit is connected to the clock input port of the chaotic signal generation unit; the output port of the service signal input unit is connected to the input port of the attenuator unit; the output ports of both the chaotic signal generation unit and the attenuator unit are connected to the input port of the signal aliasing unit; and the output port of the signal aliasing unit is connected to the scattering channel.

[0039] In the transmitting end, the chaotic source unit generates broadband optical chaos based on nonlinear intensity modulation using a Mach-Zehnder modulator; the filtering and sampling unit processes the broadband chaotic signal to obtain a digital random sequence; the BeiDou timing unit obtains a precise clock by receiving BeiDou satellite signals; the clock unit receives the precise clock output by the BeiDou system and drives the generation of chaotic signals; the chaotic signal generation unit generates a noise-like narrowband chaotic signal; the service signal input unit carries the service information to be transmitted and imports it into the chaotic system; the attenuator unit is used to reduce the strength of the input service signal; the signal aliasing unit superimposes the narrowband chaotic signal with the service signal to obtain a chaotic carrier mixing superposition signal that presents a chaotic signal appearance. The aliased service signal cannot be directly distinguished from the spectrum or time domain, thereby achieving secure signal transmission.

[0040] The chaotic source unit is used to generate broadband chaotic signals with quasi-randomness and unpredictability.

[0041] The filtering and sampling unit is used to discretize and quantize the continuous broadband chaotic signal generated by the chaotic source unit to obtain a digital random sequence.

[0042] The BeiDou timing unit is used to receive time signals from the BeiDou satellite navigation system, providing a unified and accurate clock reference for the operation of the chaotic system.

[0043] The clock unit is used to ensure timing synchronization and prevent the chaotic system from deviating from the expected dynamic behavior due to timing disorder.

[0044] The chaotic signal generation unit is used to generate a noise-like narrowband chaotic signal by converting a digital random sequence into an analog signal under the clock drive of the clock unit.

[0045] The service signal input unit is used to import the information to be transmitted into the chaotic system and complete the initial adaptation between the service information and the chaotic carrier signal.

[0046] The attenuator unit is used to attenuate the service signal input to the service signal input unit so that it presents a low amplitude.

[0047] The signal aliasing unit is used to superimpose the service signal input through the attenuator unit with the narrowband chaotic signal to obtain an encrypted signal with chaotic carrier frequency mixing and superposition, thereby realizing secure signal transmission.

[0048] The receiving end includes a chaotic source unit, a filtering and sampling unit, a BeiDou timing unit, a clock unit, a chaotic signal generation unit, a signal extraction unit, and a service signal output unit. The output port of the chaotic source unit is connected to the input port of the filtering and sampling unit; the output port of the BeiDou timing unit is connected to the input port of the clock unit; the output ports of both the filtering and sampling unit and the clock unit are connected to the clock input port of the chaotic signal generation unit; the output port of the chaotic signal generation unit is connected to the input port of the signal extraction unit; the input port of the signal extraction unit is also connected to the scattering channel; and the output port of the signal extraction unit is connected to the input port of the service signal output unit.

[0049] In the receiving end, the chaotic source unit consists of devices with the same parameters as the transmitting end, which generates a broadband chaotic signal through nonlinear intensity modulation based on a Mach-Zehnder modulator; the filtering and sampling unit processes the broadband chaotic signal to obtain a digital random sequence; the BeiDou timing unit obtains a precise clock by receiving BeiDou satellite signals and synchronizes the clocks of the transmitting and receiving ends through clock discipline technology; the clock unit receives the precise clock output by the BeiDou system and drives the generation of the chaotic signal; the chaotic signal generation unit generates a noise-like narrowband chaotic signal; the signal extraction unit subtracts the chaotic carrier mixing and superposition signal transmitted from the transmitting end from the narrowband chaotic signal generated by the receiving end to recover the service signal; the service signal output unit recovers the original service signal and outputs it.

[0050] The chaotic source unit is used to generate broadband chaotic signals with quasi-randomness and unpredictability.

[0051] The filtering and sampling unit is used to discretize and quantize the continuous broadband chaotic signal to obtain a digital random sequence.

[0052] The BeiDou timing unit is used to receive time signals from the BeiDou satellite navigation system, providing a unified and accurate clock reference for the operation of the chaotic system.

[0053] The clock unit is used to ensure timing synchronization and prevent the chaotic system from deviating from the expected dynamic behavior due to timing disorder.

[0054] The chaotic signal generation unit is used to generate a noise-like narrowband chaotic signal by converting a digital random sequence into an analog-to-digital signal under the clock drive of the clock unit.

[0055] The signal extraction unit is used to perform a subtraction operation between the chaotic masking signal (i.e., the chaotic carrier mixing and superposition signal) transmitted by the transmitting end and the narrowband chaotic signal generated by the receiving end, so as to cancel out the chaotic carrier and recover the original service signal.

[0056] The service signal output unit is used to restore the format and optimize the quality of the decrypted and recovered original service signal before outputting it.

[0057] like Figure 3 As shown, this invention also discloses a method for protecting the security of chaotic synchronization information based on BeiDou receiver timing, comprising the following steps:

[0058] S1. At the transmitting end, the broadband chaotic source generates a digital random sequence after filtering and sampling. Driven by the clock output by the Beidou timing unit, and after digital-to-analog conversion processing by the chaotic signal generation unit, a noise-like narrowband chaotic signal is generated. The low-amplitude service signal attenuated by the attenuator is mixed and encrypted with the narrowband chaotic signal in the signal mixing unit to obtain a chaotic carrier mixing superposition signal. Since the amplitude of the narrowband chaotic signal is much larger than that of the service signal, the superimposed signal will present a chaotic appearance. The superimposed service signal cannot be directly distinguished from the spectrum or time domain, thus realizing the secure transmission of the signal.

[0059] Specifically, such as Figure 2 As shown (solid lines in the diagram represent electrical signal connections, and dashed lines represent optical signal connections), a laser provides the light source, which is input to a photoelectric feedback loop consisting of a Mach-Zehnder intensity modulator, an optical fiber delay line, a photodetector, and an RF amplifier connected in sequence. The signal within the loop continuously undergoes a cycle of "nonlinear modulation-feedback superposition-remodulation," ultimately outputting a quasi-random, unpredictable broadband chaotic signal. A digital random sequence is obtained by filtering and sampling the chaotic signal. The BeiDou time receiver receives the clock signal from the BeiDou satellites. Driven by the 10MHz clock signal output from the BeiDou time receiver, the random sequence is converted from digital to analog by the signal generation module, generating a noise-like narrowband chaotic signal. The service signal to be transmitted is then attenuated and superimposed on the narrowband chaotic signal to obtain a chaotic carrier mixing superposition signal, achieving signal encryption.

[0060] S2, the scattering channel, securely and with low distortion transmits the aliased and encrypted carrier signal from the transmitter to the receiver.

[0061] Specifically, the scattering channel carries a chaotic carrier mixing superposition signal composed of the narrowband chaotic signal and the service signal superimposed at the transmitting end, which is transmitted to the receiving end in microwave form.

[0062] S3. At the receiving end, the clock signal output by the BeiDou timing unit is precisely synchronized with the transmitting end, driving the chaotic source and filtering sampling unit to obtain a digital random sequence. This enables the receiving end to generate a synchronized chaotic time sequence (i.e., a digital random sequence). Since this sequence is generated by the chaotic source unit and filtering sampling unit with the same parameters as the transmitting end, the chaotic time sequences at both ends are completely consistent. Subsequently, the chaotic carrier mixed superposition signal transmitted by the transmitting end and the narrowband chaotic signal at the receiving end are subtracted in the signal extraction unit to cancel out the chaotic carrier and recover the original service signal.

[0063] Specifically, by using devices with parameters identical to those at the transmitting end to obtain the same broadband chaotic signal, a digital random sequence is obtained through filtering and sampling. The BeiDou timing system receives precise clock signals from BeiDou satellites, and synchronizes the clocks of the transmitting and receiving ends through clock discipline technology. The digital random sequence, driven by the clock, is processed by digital-to-analog conversion in the signal generation unit to obtain a synchronized narrowband chaotic signal. Finally, a subtraction operation is performed with the chaotic carrier aliasing signal transmitted from the transmitting end to recover the service signal.

[0064] like Figure 4 The diagram illustrates a situation where timing is not synchronized via a BeiDou receiver, and two non-synchronous clocks are used. During prolonged operation, while the clock signal frequencies are consistent, phase drift occurs, leading to asynchrony of chaotic signals at the transmitting and receiving ends. This clock asynchrony causes irreversible deviations in the chaotic trajectories at both ends, completely disrupting chaotic synchronization between the transmitter and receiver. In this state, the chaotic system cannot demodulate service information, as shown below. Figure 5 As shown.

[0065] like Figure 6 The diagram shows a system using a BeiDou receiver for time synchronization. The clock signal source is a satellite-based atomic clock. The system relies on space-to-ground time calibration, while the terminal relies on local real-time discipline. The clock signal can achieve nanosecond-level stability, enabling system synchronization. When the clock signals are synchronized, the chaotic sequences at the transmitting and receiving ends are also synchronized, aligning the two chaotic signals. At this point, the two transmitted chaotic carrier waves can be subtracted and canceled out to demodulate the service information, meeting the requirements for chaotic synchronous communication. Figure 7 As shown.

[0066] The above embodiments are merely specific examples to further illustrate the purpose, technical solution, and beneficial effects of the present invention, and the present invention is not limited thereto. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the disclosure of the present invention are included within the protection scope of the present invention.

Claims

1. A chaotic synchronization information security protection system based on BeiDou receiver time synchronization, characterized in that: It includes a transmitter, a scattering channel, and a receiver connected in sequence; The transmitting end generates a high-performance ultra-wideband chaotic source based on the photoelectric feedback loop. Through filtering, sampling, digital-to-analog conversion, and high-precision clock output from the Beidou timing unit, it generates a noise-like narrowband chaotic signal. The service signal is then superimposed with the narrowband chaotic signal to obtain a chaotic carrier mixing superposition signal, thereby encrypting the transmitted information. The scattering channel is used to establish a stable transmission link between the transceiver and the receiver, and to transmit the chaotic carrier mixing and superimposed signal to the receiver. The receiving end obtains a digital random sequence by using a chaotic source and a filtering sampling unit with the same parameters as the transmitting end, and obtains a synchronized narrowband chaotic signal under the drive of a high-precision synchronous clock output by the Beidou timing unit. Then, it performs a subtraction operation between the chaotic carrier mixing and superposition signal transmitted by the transmitting end and the narrowband chaotic signal to recover the original service signal.

2. The chaotic synchronization information security protection system based on Beidou receiver timing as described in claim 1, characterized in that: The transmitting end includes a chaos source unit, a filtering and sampling unit, a BeiDou timing unit, a clock unit, a chaos signal generation unit, a service signal input unit, an attenuator unit, and a signal aliasing unit; The output port of the chaotic source unit is connected to the input port of the filtering sampling unit, the output port of the BeiDou timing unit is connected to the input port of the clock unit, the output port of the filtering sampling unit is connected to the chaotic signal input port of the chaotic signal generation unit, the output port of the clock unit is connected to the clock input port of the chaotic signal generation unit, the output port of the service signal input unit is connected to the input port of the attenuator unit, the output ports of both the chaotic signal generation unit and the attenuator unit are connected to the input port of the signal aliasing unit, and the output port of the signal aliasing unit is connected to the scattering channel.

3. The chaotic synchronization information security protection system based on Beidou receiver timing as described in claim 1, characterized in that: The receiving end includes a chaos source unit, a filtering and sampling unit, a BeiDou time synchronization unit, a clock unit, a chaos signal generation unit, a signal extraction unit, and a service signal output unit; The output port of the chaotic source unit is connected to the input port of the filtering sampling unit, the output port of the Beidou timing unit is connected to the input port of the clock unit, the output ports of the filtering sampling unit and the clock unit are both connected to the clock input port of the chaotic signal generation unit, the output port of the chaotic signal generation unit is connected to the input port of the signal extraction unit, the input port of the signal extraction unit is also connected to the scattering channel, and the output port of the signal extraction unit is connected to the input port of the service signal output unit.

4. The chaotic synchronization information security protection system based on Beidou receiver timing as described in claim 1, characterized in that: The chaotic source unit at the transmitting end and the chaotic source unit at the receiving end are the same, both of which are provided by a laser and input into a photoelectric feedback loop consisting of a Mach-Zehnder intensity modulator, an optical fiber delay line, a photodetector, and a radio frequency amplifier. The signal in the loop continuously undergoes a cycle of "nonlinear modulation-feedback superposition-remodulation", and finally outputs a quasi-random, unpredictable broadband chaotic signal. Finally, a digital random sequence is obtained by filtering and sampling the chaotic signal.

5. A method for protecting the security of chaotic synchronization information based on BeiDou receiver time synchronization, used in the chaotic synchronization information security protection system based on BeiDou receiver time synchronization as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. At the transmitting end, the broadband chaotic source generates a digital random sequence after filtering and sampling. Driven by the clock output by the Beidou timing unit, and after digital-to-analog conversion processing by the chaotic signal generation unit, a noise-like narrowband chaotic signal is generated. The low-amplitude service signal attenuated by the attenuator is mixed and encrypted with the narrowband chaotic signal in the signal mixing unit to obtain a chaotic carrier mixing superimposed signal, thereby realizing the secure transmission of the signal. S2, the scattering channel, securely and with low distortion transmits the chaotic carrier mixing and superposition signal encrypted by the transmitter to the receiver. S3. The receiving end obtains a digital random sequence by using a chaotic source and a filtering sampling unit with the same parameters as the transmitting end, and obtains a narrowband chaotic signal synchronized with the transmitting end under the high-precision synchronous clock output by the Beidou timing unit. Then, the chaotic carrier mixing and superposition signal transmitted by the transmitting end and the narrowband chaotic signal of the receiving end are subtracted in the signal extraction unit to cancel out the chaotic carrier and recover the original service signal.

6. A method for protecting the security of chaotic synchronization information based on BeiDou receiver timing according to claim 5, characterized in that: In step S1, A laser provides the light source, which is input into a photoelectric feedback loop consisting of a Mach-Zehnder intensity modulator, an optical fiber delay line, a photodetector, and an RF amplifier. The signal within the loop continuously undergoes a cycle of "nonlinear modulation-feedback superposition-remodulation," ultimately outputting a quasi-random, unpredictable broadband chaotic signal. A digital random sequence is obtained by filtering and sampling the broadband chaotic signal. The BeiDou timing unit receives the clock signal from the BeiDou satellite. Driven by the 10MHz clock signal output by the BeiDou timing unit, the digital random sequence is converted from digital to analog by the chaotic signal generation unit to generate a noise-like narrowband chaotic signal. The service signal to be transmitted is then attenuated and superimposed with the narrowband chaotic signal to obtain a chaotic carrier mixing superposition signal, achieving the purpose of signal encryption.

7. A method for protecting the security of chaotic synchronization information based on BeiDou receiver timing as described in claim 6, characterized in that: In step S3, By using devices with parameters identical to those of the transmitting end, the same broadband chaotic signal is obtained, and a digital random sequence is obtained through filtering and sampling. The BeiDou timing unit receives the precise clock signal from the BeiDou satellite, and synchronizes the clocks of the transmitting and receiving ends through clock discipline technology. The digital random sequence is then processed by the digital-to-analog conversion of the signal generation unit under clock drive to obtain a synchronized narrowband chaotic signal. Finally, the signal is subtracted from the chaotic carrier mixing and superposition signal transmitted by the transmitting end to recover the service signal.

Images