A satellite-ground cooperative data security transmission method

Abstract

The present application relates to a kind of star ground collaborative data security transmission methods, belong to safe communication technical field;Service station is first obtained the electromagnetic environment around ground terminal, marks the characteristic parameter of each electromagnetic signal, and calculates the carrier fitness of each electromagnetic signal accordingly;Then satellite will be sent information is divided according to priority;Finally, different priority information to be sent matches different carrier fitness electromagnetic signal, and the transmission of information is completed;The star ground collaborative data security transmission method of the present application reduces the detectability of star-ground link communication by the covert transmission based on information priority division, improves the robustness of covert transmission, provides a solution for improving the security of satellite data transmission.

Description

Technical Field

[0001] This invention belongs to the field of secure communication technology and relates to a method for secure data transmission in a satellite-ground coordinated manner. Background Technology

[0002] With the continuous deployment of low-Earth orbit constellations and the constant advancement of satellite communication technology, various novel satellite applications are emerging. Future satellite communication networks will effectively meet users' real-time, all-area communication needs, providing a powerful supplement to traditional terrestrial communication networks. However, due to the open nature of radio media, when data is transmitted between a ground terminal and a satellite, receivers in the same area can receive the radio signal. Therefore, satellite-to-ground links are vulnerable to eavesdropping. Traditional methods mostly employ encryption to improve information transmission security, but the act of encryption itself attracts the attention of eavesdroppers, leading to targeted eavesdropping and interference. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a data security transmission method for satellite-ground collaboration. By using covert transmission based on information priority division, the detectability of satellite-ground link communication is reduced, the robustness of covert transmission is improved, and a solution is provided to enhance the security of satellite data transmission.

[0004] The solution of the present invention is:

[0005] A method for secure data transmission via satellite-ground collaboration includes:

[0006] Establish a secure data transmission system, including ground terminals, satellites, and service stations;

[0007] The service station detects electromagnetic signals near the ground terminal and marks the characteristic parameters of each electromagnetic signal; a total of M electromagnetic signals and n characteristic parameters are set; the i-th electromagnetic signal is denoted as I. i ; the i-th electromagnetic signal I i The j-th feature parameter is denoted as I. i,j Where i is the index of the electromagnetic signal, and j is the index of the characteristic parameter; calculate the i-th electromagnetic signal I. i Carrier fit A i ;

[0008] The detected electromagnetic signal I i According to carrier suitability A i Sort the values ​​from largest to smallest; then sort the electromagnetic signals and their respective I values. i All corresponding characteristic parameters are shared to the ground terminal and satellite;

[0009] The ground terminal and satellite receive the sorted electromagnetic signals and each electromagnetic signal I. i After obtaining all the corresponding feature parameters, they are stored in a local lookup table and labeled Table1.

[0010] The satellite divides the information S to be transmitted into sub-information sequences S. i And for each sub-information sequence S i Sort the information sequences from highest to lowest priority; the satellite will then sort each sub-information sequence S. i Spread spectrum to E i and the sub-information sequence S i The partitioning strategy and spreading factor information are recorded as a decoding information table, labeled Table2; and Table2 is sent to the ground terminal.

[0011] The satellite will sort the sub-information sequences S i With sorted electromagnetic signal I i One-to-one correspondence; and according to S i Corresponding I i The characteristic parameters of S i Spread spectrum E i Modulation processing is performed, and the modulated E i Send to ground terminal;

[0012] The ground terminal receives the modulated E signal from the satellite. i Then, based on Table1 and Table2, obtain the information S to be sent.

[0013] In the aforementioned satellite-ground collaborative data security transmission method, both the ground terminal and the satellite can flexibly change the frequency, bandwidth, and waveform; the service station enables communication between the ground terminal and the satellite and has the function of identifying radio waves.

[0014] In the aforementioned method for secure data transmission via satellite-ground collaboration, the characteristic parameters of the electromagnetic signal include, but are not limited to, power, modulation scheme, bandwidth, frequency, and duty cycle.

[0015] In the aforementioned satellite-ground collaborative data security transmission method, the i-th electromagnetic signal I... i Carrier fit A i The calculation method is as follows:

[0016] S1. Eliminate signals that are outside the range of characteristic parameter adjustment capability;

[0017] S2. Calculate each characteristic parameter I using the Analytic Hierarchy Process (AHP). i,j The corresponding proportionality coefficient a j ;

[0018] S3, For each characteristic parameter Ii,j Perform normalization processing;

[0019] S4. Calculate each electromagnetic signal I. i Carrier fit A i .

[0020] In the aforementioned method for secure data transmission via satellite-ground coordination, step S3 includes the normalization of power, modulation scheme, bandwidth, and duty cycle.

[0021] In the aforementioned satellite-ground collaborative data security transmission method, in step S4, the carrier fitness A... i The calculation method is as follows:

[0022] A i =a1·I i,1 +a2·I i,1 +…a j ·I i,j …+a n ·I i,n

[0023] In the formula, a j Let I be the j-th characteristic parameter of the i-th electromagnetic signal. i,j The corresponding proportionality coefficient.

[0024] In the aforementioned satellite-ground collaborative data security transmission method, the carrier fitness A i The larger the value, the higher the reliability of the corresponding electromagnetic signal.

[0025] In the aforementioned satellite-ground collaborative data security transmission method, the satellite divides the information S to be transmitted into k sub-information sequences, namely S1, S2, ..., S... i S k Where S = S1∪S2∪…∪S i ∪…∪S k .

[0026] In the aforementioned method for secure data transmission via satellite-ground collaboration, g(S) is used. i ) represents the sub-information sequence S i The priority is determined by g(S1) > g(S2) > ... > g(S2). k ).

[0027] In the aforementioned method for secure data transmission via satellite-ground collaboration, the specific method by which the ground terminal obtains the information S to be sent based on Table 1 and Table 2 is as follows:

[0028] S1, Ground terminal receives E after modulation processing i Then, obtain E by traversing Table1.i Before spread spectrum S i Corresponding electromagnetic signal I i All characteristic parameters; based on the characteristic parameters, the modulation of E is realized. i The reception and demodulation of E enable the reception and demodulation of E. i Information acquisition;

[0029] S2, the ground terminal looks up the spreading factor according to Table 2, and then... i Despreading is performed to obtain the corresponding sub-information sequence S. i Then, based on Table 2, obtain S. i The partitioning strategy combines the sub-information sequences S i Information S is obtained.

[0030] The advantages of this invention compared to the prior art are:

[0031] (1) Compared with existing covert communication that uses idle spectrum resources for information transmission, the present invention transmits information by hiding it on existing electromagnetic signals in the surrounding area, which has stronger camouflage and concealment, and also saves more spectrum resources.

[0032] (2) The covert transmission method based on information priority division proposed in this invention selects different covert strategies, namely different carrier signals and spreading factors, according to the importance of the information to be transmitted. Compared with the prior art, it prioritizes the transmission of important information and has stronger flexibility and robustness in covert information transmission;

[0033] (3) This invention proposes a method for calculating carrier suitability, which provides a basis for the selection of frequency resources for covert transmission. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the data security transmission process for satellite-ground collaboration according to the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the embodiments.

[0036] This invention provides a method for secure data transmission in a satellite-ground collaborative manner. By using covert transmission based on information priority division, the detectability of satellite-ground link communication is reduced, and the robustness of covert transmission is improved, providing a solution for enhancing the security of satellite data transmission.

[0037] Secure data transmission methods for satellite-ground collaboration, such as Figure 1 As shown, the specific steps include the following:

[0038] A secure data transmission system is established, comprising a ground terminal, a satellite, and a service station. Both the ground terminal and the satellite can flexibly change their frequency, bandwidth, and waveform. The service station enables communication between the ground terminal and the satellite and has the function of identifying radio waves.

[0039] The service station detects electromagnetic signals near the ground terminal and marks the characteristic parameters of each electromagnetic signal. These characteristic parameters include, but are not limited to, power, modulation method, bandwidth, frequency, and duty cycle. A total of M electromagnetic signals and n characteristic parameters are defined; the i-th electromagnetic signal is denoted as I. i ; the i-th electromagnetic signal I i The j-th feature parameter is denoted as I. i,j Where i is the index of the electromagnetic signal, and j is the index of the characteristic parameter; calculate the i-th electromagnetic signal I. i Carrier fit A i .

[0040] In this invention, the i-th electromagnetic signal I i Carrier fit A i The calculation method is as follows:

[0041] S1. Eliminate signals that are outside the range of characteristic parameter adjustment capability;

[0042] S2. Calculate each characteristic parameter I using the Analytic Hierarchy Process (AHP). i,j The corresponding proportionality coefficient a j ;

[0043] S3, For each characteristic parameter I i,j Normalization is performed; the normalization process includes power normalization, modulation mode normalization, bandwidth normalization, and duty cycle normalization.

[0044] S4. Calculate each electromagnetic signal I. i Carrier fit A i .

[0045] Carrier fit A i The calculation method is as follows:

[0046] A i =a1·I i,1 +a2·I i,1 +…a j ·I i,j …+a n ·I i,n

[0047] In the formula, a j Let I be the j-th characteristic parameter of the i-th electromagnetic signal. i,j The corresponding proportionality coefficient.

[0048] Carrier fit A i The larger the value, the higher the reliability of the corresponding electromagnetic signal.

[0049] The detected electromagnetic signal I i According to carrier suitability A i Sort the values ​​from largest to smallest; then sort the electromagnetic signals and their respective I values. i All corresponding characteristic parameters are shared with the ground terminal and satellite.

[0050] The ground terminal and satellite receive the sorted electromagnetic signals and each electromagnetic signal I. i After obtaining all the corresponding feature parameters, they are stored in a local lookup table and labeled Table1.

[0051] The satellite divides the information S to be transmitted into sub-information sequences S. i And for each sub-information sequence S i Sort by priority from highest to lowest.

[0052] Specifically, the satellite divides the information S to be transmitted into k sub-information sequences, namely S1, S2, ..., S... i S k Where S = S1∪S2∪…∪S i ∪…∪S k Using g(S) i ) represents the sub-information sequence S i The priority is determined by g(S1) > g(S2) > ... > g(S2). k ).

[0053] The satellite will transmit each sub-information sequence S i Spread spectrum to E i and the sub-information sequence S i The partitioning strategy and spreading factor information are recorded as a decoding information table, labeled Table2; and Table2 is sent to the ground terminal.

[0054] The satellite will sort the sub-information sequences S i With sorted electromagnetic signal I i One-to-one correspondence; and according to S i Corresponding I i The characteristic parameters of S i Spread spectrum E i Modulation processing is performed, and the modulated E i Send to the ground terminal.

[0055] The ground terminal receives the modulated E signal from the satellite. i Then, based on Table1 and Table2, obtain the information S to be sent.

[0056] The specific method by which the ground terminal obtains the information S to be sent based on Table1 and Table2 is as follows:

[0057] S1, Ground terminal receives E after modulation processing i Then, obtain E by traversing Table1. i Before spread spectrum S i Corresponding electromagnetic signal I i All characteristic parameters; based on the characteristic parameters, the modulation of E is realized. i The reception and demodulation of E enable the reception and demodulation of E. i Information acquisition;

[0058] S2, the ground terminal looks up the spreading factor according to Table 2, and then... i Despreading is performed to obtain the corresponding sub-information sequence S. i Then, based on Table 2, obtain S. i The partitioning strategy combines the sub-information sequences S i Information S is obtained.

[0059] Example

[0060] (1) The service station acquires electromagnetic signals I from the surrounding area of ​​the ground terminal. i The characteristic parameters;

[0061] The service station detects electromagnetic signals around the ground terminal. Assume it detects 10 signals, labeled I1, I2, ..., I... 10 Record the characteristic parameters of these 10 signals, such as signal power, modulation method, bandwidth, frequency, duty cycle, etc., and label them as I. i,1 I i,2 I i,3 I i,4 I i,5 Where the subscript i represents the i-th signal. Specific values ​​are shown in the table below:

[0062] Table 1 Characteristic parameters of electromagnetic signals around the terminal

[0063]

[0064] (2) Service station calculates electromagnetic signal I i Carrier fit A i ;

[0065] Step 2.1: Eliminate signals that are not within the adjustment capabilities of the ground terminal.

[0066] Assuming both the ground terminal and the satellite employ software-definable technology, with frequency adjustable within the 20GHz-30GHz range, and selectable modulation schemes including BPSK, QPSK, 8PSK, 16PSK, 16QAM, and 64QAM, and adjustable bandwidth from 0 to 100MHz, then signals I1, I2, I3, and I5 are eliminated because their frequencies are outside the adjustable range of the ground terminal; signal I7 is also eliminated because its modulation scheme is outside the adjustable range of the ground terminal.

[0067] Step 2.2: Calculate the proportionality coefficient α corresponding to the characteristic parameters. n ;

[0068] After the filtering in step 2.1, signals I4, I6, I8, I9, and I... 10 The frequencies are all within the adjustable range of the ground terminal (20GHz~30GHz). Therefore, the weights of the remaining four characteristic parameters (power, modulation method, bandwidth, and duty cycle) are calculated. The specific steps are as follows:

[0069] ■ Constructing the judgment matrix: Using the expert method, the importance of each feature parameter is compared and scored pairwise. The results are as follows:

[0070]

[0071] The specific numerical values ​​of the matrix are determined using the 1-9 scaling method proposed by TLSatty.

[0072]

[0073] ■ Calculate the weights of each feature parameter and perform normalization.

[0074]

[0075]

[0076] After normalization: α1 = 0.2222, α2 = 0.1111, α3 = 0.3333, α4 = 0.3333.

[0077] Step 2.3: Normalize the values ​​of each feature parameter;

[0078] The power normalization method is as follows: Where P min P represents the minimum power in the acquired signal, and P represents the power of the currently acquired signal.

[0079] Then, I4, I6, I8, I9, I 10 The power parameter value is: I 4,1 =0.8, I 6,1 =1、I8,1 =0.6, I 9,1 =0.4, I 101 =0.

[0080] The normalization method for the modulation scheme is as follows:

[0081] Then, I4, I6, I8, I9, I 10 The modulation parameter value is: I 4,2 =0.8, I 6,2 =0.9, I 8,2 =0.5, I 9,2 =0.8, I 10,2 =0.9.

[0082] The bandwidth normalization method is as follows: Among them W max W represents the maximum bandwidth of the acquired signal, and W represents the bandwidth of the currently acquired signal.

[0083] Then, I4, I6, I8, I9, I 10 The bandwidth parameter value is: I 4,3 =1、I 6,3 =0.5, I 8,3 =0.71, I 9,3 =0.61, I 10,3 =0.45.

[0084] The duty cycle normalization method is as follows: Among them, T max This represents the maximum duty cycle in the acquired signal, and T represents the duty cycle of the currently acquired signal.

[0085] Then, I4, I6, I8, I9, I 10 The duty cycle parameter value is: I 4,4 =1、I 6,4 =0.71, I 8,4 =1、I 9,4 =0.71, I 10,4 =1.

[0086] Step 2.4: Calculate the carrier fitness A for each signal. i ;

[0087] Among them, A i The calculation method is as follows: A i =α1*I i,1 +α2*I i,2 +….+α n *I i,n .

[0088] Then, A4 = α1*I 4,1+α2*I 4,2 +α3*I 4,3 +α4*I 4,4 =0.9332;

[0089] A6=α1*I 6,1 +α2*I 6,2 +α3*I 6,3 +α4*I 6,4 =0.7255;

[0090] A8=α1*I 8,1 +α2*I 8,2 +α3*I 8,3 +α4*I 8,4 =0.7588;

[0091] A9=α1*I 9,1 +α2*I 9,2 +α3*I 9,3 +α4*I 9,4 =0.6177;

[0092] A 10 =α1*I 10,1 +α2*I 10,2 +α3*I 10,3 +α4*I 10,4 =0.5833;

[0093] Since A4>A8>A6>A9>A 10 Therefore, the most suitable carrier for concealment is electromagnetic signal I4, followed by I8, I6, I9, and I... 10 .

[0094] (3) The service station will A i The characteristic parameters are shared with the satellite and ground terminal through a dedicated channel, and the satellite and ground terminal store them in lookup table Table1;

[0095] (4) The satellite prioritizes the information S to be transmitted and spreads it.

[0096] Let's take the transmission of compressed video information from a ground terminal as an example. Assume information S is a video compression stream using the IPPP… bitstream structure. The stream mainly contains SPS (Sequence Parameters), PPS (Picture Parameters), I-frames, and P-frames. SPS and PPS contain common settings information for the stream, such as resolution, quality level, and quantization parameters. Loss of SPS / PPS information will render the entire video stream undecoded, making it crucial information for decoding. Similarly, loss of I-frame information will render subsequent P-frames (P-frames preceding the next I-frame) undecoded, also important information for decoding.

[0097] Step 4.1: Information segmentation;

[0098] Based on their importance during decoding, the S information can be divided into three parts: S1, S2, and S3, where S = S1∪S2∪S3. S1 contains SPS and PPS information, S2 contains I-frame information, and S3 contains P-frame information. Therefore, g(S1) > g(S2) > g(S3), and g(S... i ) represents signal S i Priority.

[0099] Step 4.2: Information Spread Spectrum;

[0100] Information S1, S2, and S3 are spread by spreading factors m1, m2, and m3 (m1 ≥ m2 ≥ m3), and the spread information is denoted as E1, E2, and E3.

[0101] Step 4.3: Policy sharing;

[0102] The satellite records the partitioning strategy of S1, S2, and S3, as well as the spreading factors m1, m2, and m3, into a decoding information table, labeled Table2. Table2 is then shared with the ground via a dedicated link.

[0103] (5) Satellite simulation information I i Transmit the spread spectrum information E to the terminal i ;

[0104] As can be seen from step (2), the most suitable carrier for concealment is signal I4, followed by I8, I6, I9, and I... 10 Therefore, the characteristic parameters (modulation method, bandwidth, frequency, duty cycle) of I4, I8, and I6 are selected to transmit E1, E2, and E3.

[0105] That is, E1 uses 8PSK modulation, 40MHz bandwidth, 100% duty cycle, and transmits at 20.8GHz; E2 uses 64QAM modulation, 20MHz bandwidth, 100% duty cycle, and transmits at 21GHz; E3 uses QPSK modulation, 10MHz bandwidth, 50% duty cycle, and transmits at 20GHz.

[0106] (6) Terminal acquires information S;

[0107] First, the terminal can obtain parameters such as modulation scheme, bandwidth, frequency, etc. of the three signals by traversing the fitness lookup table Table1. Based on this, it can complete signal reception and demodulation, and acquire information E1, E2, and E3.

[0108] Then, the terminal looks up the spreading factor according to Table2, despreads E1, E2, and E3, and obtains information S1, S2, and S3;

[0109] Finally, based on Table 2, we learn the partitioning strategies of S1, S2, and S3, and combine S1, S2, and S3 to obtain information S.

[0110] Compared with existing covert communication methods that use idle spectrum resources for information transmission, this invention transmits information by hiding it in existing electromagnetic signals in the surrounding area, which has stronger camouflage and concealment, and also saves more spectrum resources.

[0111] This invention proposes a covert transmission method based on information priority partitioning. Different covert strategies, namely different carrier signals and spreading factors, are selected according to the importance of the information to be transmitted. Compared with existing technologies, this method prioritizes the transmission of important information, resulting in greater flexibility and robustness in covert transmission. This invention also proposes a method for calculating carrier suitability, providing a basis for frequency resource selection in covert transmission.

[0112] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for secure data transmission via satellite-ground collaboration, characterized in that: include: Establish a secure data transmission system, including ground terminals, satellites, and service stations; The service station detects electromagnetic signals near the ground terminal and marks the characteristic parameters of each electromagnetic signal. There are M electromagnetic signals and n characteristic parameters. Let the i-th electromagnetic signal be denoted as I. i ; the i-th electromagnetic signal I i The j-th feature parameter is denoted as I. i,j Where i is the index of the electromagnetic signal, and j is the index of the characteristic parameter; calculate the i-th electromagnetic signal I. i Carrier fit A i ; The detected electromagnetic signal I i According to carrier suitability A i Sort the values ​​from largest to smallest; then sort the electromagnetic signals and their respective I values. i All corresponding characteristic parameters are shared to the ground terminal and satellite; The ground terminal and satellite receive the sorted electromagnetic signals and each electromagnetic signal I. i After obtaining all the corresponding feature parameters, they are stored in a local lookup table and labeled Table1. The satellite divides the information S to be transmitted into sub-information sequences S. i And for each sub-information sequence S i Sort the information sequences from highest to lowest priority; the satellite will then sort each sub-information sequence S. i Spread spectrum to E i and the sub-information sequence S i The partitioning strategy and spreading factor information are recorded as a decoding information table, labeled Table2; and Table2 is sent to the ground terminal. The satellite will sort the sub-information sequences S i With sorted electromagnetic signal I i One-to-one correspondence; and according to S i Corresponding I i The characteristic parameters of S i Spread spectrum E i Modulation processing is performed, and the modulated E i Send to ground terminal; The ground terminal receives the modulated E signal from the satellite. i Then, based on Table1 and Table2, obtain the information S to be sent.

2. The data security transmission method for satellite-ground collaboration according to claim 1, characterized in that: Both the ground terminal and the satellite can flexibly change the frequency, bandwidth, and waveform; the service station enables communication between the ground terminal and the satellite and has the function of identifying radio waves.

3. The data security transmission method for satellite-ground collaboration according to claim 1, characterized in that: The characteristic parameters of the electromagnetic signal include, but are not limited to, power, modulation method, bandwidth, frequency, and duty cycle.

4. The data security transmission method for satellite-ground collaboration according to claim 1, characterized in that: The i-th electromagnetic signal I i Carrier fit A i The calculation method is as follows: S1. Eliminate signals that are outside the range of characteristic parameter adjustment capability; S2. Calculate each characteristic parameter I using the Analytic Hierarchy Process (AHP). i,j The corresponding proportionality coefficient a j ; S3, For each characteristic parameter I i,j Perform normalization processing; S4. Calculate each electromagnetic signal I. i Carrier fit A i .

5. The data security transmission method for satellite-ground collaboration according to claim 4, characterized in that: In S3, the normalization process includes power normalization, modulation mode normalization, bandwidth normalization, and duty cycle normalization.

6. The data security transmission method for satellite-ground collaboration according to claim 5, characterized in that: In S4, the carrier fitness A i The calculation method is as follows: A i =a1·I i,1 +a2·I i,1 +…a j ·I i,j …+a n ·I i,n In the formula, a j Let I be the j-th characteristic parameter of the i-th electromagnetic signal. i,j The corresponding proportionality coefficient.

7. The data security transmission method for satellite-ground collaboration according to claim 1, characterized in that: Carrier fit A i The larger the value, the higher the reliability of the corresponding electromagnetic signal.

8. The data security transmission method for satellite-ground collaboration according to claim 1, characterized in that: The satellite divides the information S to be transmitted into k sub-information sequences, namely S1, S2, ..., S... i S k Where S = S1∪S2∪…∪S i ∪…∪S k .

9. A data security transmission method for satellite-ground collaboration according to claim 8, characterized in that: Using g(S) i ) represents the sub-information sequence S i The priority is determined by g(S1) > g(S2) > ... > g(S2). k ).

10. A data security transmission method for satellite-ground collaboration according to claim 1, characterized in that: The specific method by which the ground terminal obtains the information S to be sent based on Table1 and Table2 is as follows: S1, Ground terminal receives E after modulation processing i Then, obtain E by traversing Table1. i Before spread spectrum S i Corresponding electromagnetic signal I i All feature parameters; Based on characteristic parameters, the modulated E is processed... i The reception and demodulation of E enable the reception and demodulation of E. i Information acquisition; S2, the ground terminal looks up the spreading factor according to Table 2, and then... i Despreading is performed to obtain the corresponding sub-information sequence S. i Then, based on Table 2, obtain S. i The partitioning strategy combines the sub-information sequences S i Information S is obtained.

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