Time jitter covert communication waveform design method

Abstract

The invention discloses a time jitter covert communication waveform design method, which relates to the technical field of anti-interference, and comprises the following steps: based on a first pseudo random sequence, combining effective information and pseudo information to form modulation information; selecting a corresponding Chirp signal from the baseband waveform sample memory based on the second pseudorandom sequence; modulating the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal; and performing up-conversion processing on the baseband modulation signal, generating a transmitting signal, and transmitting the transmitting signal from a transmitting end, so as to solve the problems of weak concealment and weak anti-interception capability of the current common covert communication architecture.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-interference, and in particular relates to a time-dithered covert communication waveform design method. Background Art

[0002] In modern military activities, due to the development of information technology, the combat mode has changed from traditional large-scale conflicts to diversified combat methods such as information warfare and cyber warfare. This change has made the importance of communication security and anti-interference increasingly prominent. As an important means of maintaining physical layer information security, covert communication plays a vital role in providing confidential communications, preventing information leakage, and resisting enemy interference, providing strong support and guarantee for modern military operations.

[0003] In the existing technology, Direct Sequence Spread Spectrum (DSSS) technology and Frequency-Hopping (FH) technology are two common covert communication architectures [1][2]. The former uses a pseudo-random sequence to achieve signal spectrum expansion, submerging the signal in noise at the frequency domain level, thereby reducing the probability of being discovered; the latter is that during the communication process, the sender and receiver randomly change the carrier frequency of the signal according to a predetermined frequency hopping pattern, so that the communication signal can avoid the fading or interference range in the channel. However, since the signal characteristics of these two architectures are relatively fixed during the communication process, the current research on their detection methods is also relatively mature. Once the signal is exposed, it is easy for non-cooperative parties to estimate the corresponding parameters in the first time, thereby demodulating effective information. Therefore, scholars are in urgent need of new covert systems to adapt to the increasingly severe communication environment and challenges.

[0004] Linear Frequency Modulation (LFM) signals (also called Chirp signals) are widely used in military environments such as radar ranging due to their good time-frequency correlation [3]. At the communication level, Chirp signals have a larger spread spectrum gain than sinusoidal signals, and can resist selective fading and interference in the channel to a certain extent. Therefore, they can be used in covert communication design. At present, the conventional Chirp modulation method is to generate a dynamic control word through a frequency synthesizer to control the frequency of the oscillator to change over time to generate a Chirp signal, and replace the traditional sinusoidal waveform with the Chirp waveform during the modulation process, so that the signal bandwidth is extended to the frequency band of the Chirp signal. Compared with the commonly used covert communication architecture, Chirp Spread Spectrum (CSS) technology also has the advantages of strong anti-frequency deviation capability, long transmission distance and high parameter flexibility. Therefore, the application of Chirp signals in covert communication scenarios has important research and practical value.

[0005] At present, the CSS architecture still has certain limitations in terms of concealment. As the detection methods of periodic signals become more and more sophisticated, the detection of periodic energy convergence characteristics in the transform domain by methods such as cepstrum analysis, quadratic power spectrum method, and cyclic correlation becomes more and more mature, and Chirp signals still have a greater risk of exposure. Secondly, the anti-interception capability of single user information is also weak, so it is necessary to improve the CSS architecture at the waveform and information levels.

[0006] Chirp spread spectrum and modulation principle

[0007] Spread spectrum is a transmission method in which the bandwidth occupied by the transmitted signal is much larger than the maximum bandwidth required to send information. Direct Sequence Spread Spectrum (DSSS) spreads the spectrum by using a pseudo-random sequence independent of the transmitted data, and generates the same sequence at the receiving end for despreading and data recovery. Chirp Spread Spectrum (CSS) is one of the various spread spectrum technologies. Unlike DSSS, CSS does not require the use of pseudo-random codes to spread the spectrum. Within a certain symbol interval, the carrier frequency of the chirp signal sweeps across a certain bandwidth to spread the spectrum. Its signal expression is shown in formula (1):

[0008] s(t)=a(t)cos(2πf0t+πμt 2 )

[0009] Where a(t) is the signal envelope, which is a rectangular function. When |t|>T / 2, a(t)=0; f0 represents the carrier frequency; μ is the Chirp signal modulation frequency; T is the signal duration; then its instantaneous phase is

[0010] θ(t)=2πf0t+πμt 2

[0011] By taking the first-order and second-order derivatives of the phase of the signal, we can get the instantaneous frequency and modulation frequency of the signal:

[0012]

[0013] Among them, μ = B / T, B is the Chirp signal bandwidth, and the signal frequency increases (decreases) with time. It can be seen from the above formula that the instantaneous frequency of the Chirp signal changes linearly with time, that is, the modulation frequency μ is a constant, and the signal is a linear frequency modulation signal.

[0014] The rate of change of the instantaneous frequency of the signal is determined by the absolute value of μ, while the polarity of μ determines the direction of change of the instantaneous frequency. If μ>0, the instantaneous frequency of the signal increases linearly with time, which is an up-Chirp signal. On the contrary, if μ<0, the instantaneous frequency of the Chirp signal decreases linearly with time, which is a down-Chirp signal. The time-frequency characteristics of up- and down-Chirp signals are as follows: Figure 1 shown.

[0015] Therefore, the currently commonly used covert communication architecture has the problems of weak concealment and weak anti-interception capability. Summary of the invention

[0016] The purpose of the present invention is to provide a time-jittered covert communication waveform design method to solve the problems of weak concealment and weak anti-interception capability of the currently commonly used covert communication architecture.

[0017] To achieve the above object, the present invention adopts the following technical solution:

[0018] On the one hand, this specification provides a method for designing a covert communication waveform with time jitter, comprising:

[0019] Step 102, based on the first pseudo-random sequence, combining the valid information with the pseudo-information to form modulated information;

[0020] Step 104, selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence;

[0021] Step 106, modulating the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal;

[0022] Step 108, up-convert the baseband modulated signal to generate a transmit signal which is transmitted from the transmitting end.

[0023] On the other hand, the present specification provides a time-jittered covert communication waveform design device, comprising:

[0024] A pseudo information interleaving module, used for combining effective information with pseudo information based on a first pseudo random sequence to form modulated information;

[0025] A time domain random jitter module, used for selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence;

[0026] A signal modulation module is used to modulate the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal;

[0027] The signal transmission module is used to up-convert the baseband modulated signal to generate a transmission signal and transmit it from the transmitting end.

[0028] Based on the above technical solution, this specification can achieve the following technical effects:

[0029] This method adopts a time jitter strategy to make the signal period between different symbols show pseudo-random jumps within a specified period set, thereby overcoming the problems of obvious signal characteristics and high detection probability in some period detection methods and period characteristic spectra; at the same time, a strategy for randomly interleaving user information and pseudo-information is designed, and the transmitted information is no longer a single user information, but an information frame containing pseudo-information. The pseudo-information is also subjected to Chirp spread spectrum modulation at the sending end. Therefore, in an electromagnetic environment, even if the transmission signal is intercepted, the intercepting party cannot distinguish whether the intercepted information is useful or not because the framing method is unknown, thereby ensuring the security of communication between the two communicating parties, thereby solving the problems of weak concealment and weak anti-interception capability of the currently commonly used covert communication architecture. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the time-frequency characteristics of the Chirp signal in the background technology of the present invention.

[0031] Figure 2 The figure is a flow chart of a Kalman filter tracking method integrating LSTM state prediction in one embodiment of the present invention.

[0032] Figure 3 1 is a waveform diagram before and after Chirp-BOK modulation in one embodiment of the present invention.

[0033] Figure 4 This is a principle block diagram of a sending end in one embodiment of the present invention.

[0034] Figure 5 This is a principle block diagram of a receiving end in one embodiment of the present invention.

[0035] Figure 6 The figure is a specific design flow chart of the covert communication waveform design with time jitter in one embodiment of the present invention.

[0036] Figure 7 The figure is a schematic diagram of the structure of a device for designing a covert communication waveform with time jitter in one embodiment of the present invention.

[0037] Figure 8 The figure is a schematic diagram of an electronic device according to the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0039] It should be noted that, in order to clearly explain the content of the present invention, the present invention specifically cites multiple embodiments to further illustrate different implementations of the present invention, wherein the multiple embodiments are enumerated rather than exhaustive. In addition, for the sake of brevity of explanation, the contents mentioned in the previous embodiments are often omitted in the subsequent embodiments. Therefore, the contents not mentioned in the subsequent embodiments can refer to the previous embodiments accordingly.

[0040] Example 1

[0041] Please refer to Figure 2 , Figure 2 The figure shows a time jitter covert communication waveform design method provided by this embodiment. In this embodiment, the method includes:

[0042] Step 102, based on the first pseudo-random sequence, combining the valid information with the pseudo-information to form modulated information;

[0043] In this embodiment, one implementation of step 102 is:

[0044] Step 202, generating a random information selection control word based on a first pseudo-random sequence;

[0045] Step 204: Select a control word based on the random information to combine the valid information and the dummy information to generate modulation information.

[0046] In this embodiment, after step 204, the following steps are further included:

[0047] The modulation information is polarity-converted to obtain modulation information after polarity conversion.

[0048] Step 104, selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence;

[0049] In this embodiment, before step 104, the following steps are also included:

[0050] Step 302, storing a plurality of Chirp signals of different cycle lengths in a baseband waveform sample memory;

[0051] Step 304: construct a period set based on the period of the Chirp signal in the baseband waveform sample memory.

[0052] In this embodiment, one implementation of step 104 is:

[0053] Step 402, generating a period control word based on a second pseudo-random sequence;

[0054] Step 404, determining a target cycle from the cycle set based on a mapping relationship between the cycle control word and the cycle set;

[0055] Step 406, input the target period into the baseband waveform sample memory, and output the corresponding Chirp signal.

[0056] Step 106, modulating the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal;

[0057] Step 108, up-convert the baseband modulated signal to generate a transmit signal which is transmitted from the transmitting end.

[0058] In this embodiment, one implementation of step 108 is:

[0059] Step 502, the receiving end receives the transmitted signal to obtain a received signal;

[0060] Step 504: the receiving end performs frame processing on the received signal based on the first pseudo-random sequence to obtain a valid information frame and a pseudo information frame;

[0061] Step 506, the receiving end demodulates the valid information frame through a matched filter and outputs demodulated information;

[0062] In this embodiment, one implementation of step 506 is:

[0063] The effective information frame is matched with the local waveform sample through a matched filter, and the demodulated information is output.

[0064] In this embodiment, before step 506, the following steps are also included:

[0065] Based on the second pseudo-random sequence, generating a periodic control word of the receiving end;

[0066] Determining a target cycle of the receiving end from the cycle set based on the cycle control word;

[0067] Based on the target period, a local waveform sample corresponding to the frequency modulation rate is selected from the baseband waveform sample memory.

[0068] Step 508: The receiving end samples and compares the demodulated information to obtain valid information.

[0069] Specifically, the frequency conversion law of the Chirp signal can be used to carry information. This binary modulation is called BOK modulation. Chirp-BOK modulation uses the up-Chirp signal to represent the data information "1" and the down-Chirp signal to represent the data information "0" for data mapping, thereby mapping the corresponding waveform for transmission.

[0070] Modulation uses up-Chirp to represent data "1" and down-Chirp to represent data "0", or up-Chirp to represent data "0" and down-Chirp to represent data "1". The two mappings are equivalent. Here we use the first mapping method. The waveform after modulation is as follows Figure 3 As shown in the figure, it can be seen that it is a constant envelope modulation.

[0071] The spread spectrum characteristics of the Chirp signal itself make it have a low and flat power spectrum density, which is suitable for covert communication transmission. In addition to the above frequency domain characteristics, the present invention introduces a pseudo-information interleaving strategy at the information level and introduces random jitter in the time domain at the waveform level to further enhance its anti-interception performance. The principle block diagram of the system transmitter is as follows: Figure 4 shown.

[0072] In the pseudo-information interleaving module, a random information selection control word is generated through a pseudo-random sequence 1, and the valid information and pseudo-information are combined into an information frame with masking capability and input into the modulation module. The specific framing process is shown in formula (5).

[0073]

[0074] Among them, {a1,a2…a n} is user information, {b1,b2…b n} is pseudo information, {c1,c2…c 2n} is the modulation information after framing, {m1,m2…m 2n} is an element of pseudo-random sequence 1. Since the distribution of bits "0" and "1" in the pseudo-random sequence is relatively random, and the number of "0" and "1" that appear in each cycle is approximately equal, it is difficult for non-cooperative parties to deinterleave information and obtain user information without understanding the rules of the control word. This module has good information anti-interception capabilities.

[0075] In the modulation module, this system introduces a time domain random jitter architecture, which stores chirp signals of different period lengths in the baseband waveform sample memory and constructs a period set and {T1…T 2k}, generate a period control word through pseudo-random sequence 2, select the corresponding period in the period set and input it into the baseband waveform sample memory, and output the corresponding Chirp signal for modulation. Among them, pseudo-random sequence 2 is {m1′,m′2…m′ k …m′ g}, its control word mapping method is

[0076] X i =bin2dec({m i ′,m i ' +1 …m i ' +k})+1 (6)

[0077] Where: bin2dec(g) is the conversion symbol from binary to decimal, and X i ∈{1,…,2 k Therefore, different control words correspond to different elements in the periodic set, thereby changing the modulated signal from a single periodic signal to a signal that randomly jitters in the time domain. When facing a detection method characterized by cyclostationarity, the system has good anti-detection performance.

[0078] In this system design, the I and Q channels are combined with Chirp-BOK information modulation to generate baseband modulation signals and up-convert the signals. The modulation signal expression at the transmitter is:

[0079] s(t)=cos(2πf0t+πc′(t)μt 2 )(7)

[0080] Where: c′(t) is the modulation information after polarity conversion.

[0081] The receiving end principle block diagram is as follows Figure 5As shown, at the receiving end, because it is not necessary to receive the pseudo information, the received signal is framed through the synchronous PN sequence 1. When it is confirmed as a modulated signal corresponding to the user information, the receiving end needs to demodulate the signal through the matched filter. The local waveform sample of the matched filter generates the same periodic control word as the transmitting end through the synchronous PN sequence 2 and selects the baseband waveform with the corresponding modulation frequency. When the received signal matches the local sample, the signal outputs a pulse at the corresponding position. Otherwise, the output is relatively flat. Therefore, the output of the bit "0" and bit "1" matched filter is sampled and compared to obtain the user information.

[0082] For example, refer to Figure 6 ,The specific design process for the covert communication waveform with time jitter.

[0083] Step 1: Combine user information and pseudo information into a modulation information frame according to the method described above and pass it to the modulation module

[0084] Step 2: The modulation module is divided into three parts. First, the appropriate modulation frequency is selected to generate the local waveform base under different periods. Secondly, the corresponding waveform base is selected through the time jitter module, and the Chirp-BOK modulation method is used to generate the baseband modulation signal.

[0085] Step 3: Up-convert the baseband modulated signal to the appropriate frequency band and output the signal as RF

[0086] Step 4: The receiving end first divides the received signal into frames through the synchronized PN sequence, down-converts and demodulates the user information, and does not demodulate the pseudo information.

[0087] Step 5: After down-converting the modulated signal containing user information, first select the waveform sample of the corresponding period through PN sequence 2, and select the corresponding up-conversion Chirp and down-conversion Chirp in the local waveform set as input to the corresponding bit "0" and bit "1" matching filters.

[0088] Step 6: Input the received signal into the matched filter, then store and compare the maximum peak values ​​of the matched filter outputs of each symbol bit "0" and bit "1" to obtain the corresponding user information.

[0089] Based on this, this patent proposes a new pseudo information interleaving strategy and a time-jittered Chirp waveform-based modulation strategy from the perspective of communication system frame structure design and modulation waveform. The beneficial effects are as follows:

[0090] (1) Compared with traditional communication systems, the pseudo-information interleaving strategy reduces the risk of valid information being exposed after the transmission signal is intercepted by randomly framing valid information and pseudo-information;

[0091] (2) The latter uses a random combination of Chirp waveforms with different symbol periods to carry modulation information and achieve the effect of random time jitter.

[0092] Therefore, for non-cooperative parties, since they cannot know the pseudo-random sequence specified by the communicating parties, they cannot effectively frame the information through conventional means, and the intercepting party cannot obtain user information. The system's anti-interception performance is also strong.

[0093] In summary, this method adopts a time jitter strategy to make the signal period between different symbols show pseudo-random jumps within a specified period set, thereby overcoming the problems of obvious signal characteristics and high detection probability in some period detection methods and period characteristic spectra; at the same time, a strategy for randomly interleaving user information and pseudo-information is designed. The transmitted information is no longer a single user information, but an information frame containing pseudo-information. The pseudo-information is also Chirp spread spectrum modulated at the sending end. Therefore, in an electromagnetic environment, even if the transmission signal is intercepted, the intercepting party cannot distinguish whether the intercepted information is useful or not because it does not know the framing method, thereby ensuring the security of communication between the two communicating parties, thereby solving the problems of weak concealment and weak anti-interception capability of the currently commonly used covert communication architecture.

[0094] Example 2

[0095] Please refer to Figure 7 , Figure 7 The figure shows a time-jittered covert communication waveform design device provided by this embodiment. In this embodiment, the device includes:

[0096] A pseudo information interleaving module, used for combining effective information with pseudo information based on a first pseudo random sequence to form modulated information;

[0097] A time domain random jitter module, used for selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence;

[0098] A signal modulation module is used to modulate the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal;

[0099] The signal transmission module is used to up-convert the baseband modulated signal to generate a transmission signal and transmit it from the transmitting end.

[0100] Optionally, the pseudo information interleaving module includes:

[0101] A selection control word generation unit, configured to generate a random information selection control word based on a first pseudo-random sequence;

[0102] The true and false information modulation unit is used to select a control word based on random information to combine valid information and false information to generate modulation information.

[0103] Optionally, also include:

[0104] The polarity conversion unit is used to perform polarity conversion on the modulation information to obtain the modulation information after polarity conversion.

[0105] Optionally, also include:

[0106] A Chirp signal storage module, used for storing a number of Chirp signals of different period lengths in a baseband waveform sample memory;

[0107] The period set building module is used to build a period set based on the period of the Chirp signal in the baseband waveform sample memory.

[0108] Optional, time domain random jitter module includes:

[0109] A period control word generating unit, used for generating a period control word based on a second pseudo-random sequence;

[0110] A target cycle determination unit, configured to determine a target cycle from the cycle set based on a mapping relationship between the cycle control word and the cycle set;

[0111] The Chirp signal determination unit is used to input the target period into the baseband waveform sample memory and output the corresponding Chirp signal.

[0112] Optionally, also include:

[0113] A signal receiving module is used for receiving the transmitted signal at the receiving end to obtain a received signal;

[0114] An information framing module, used for the receiving end to perform framing processing on the received signal based on the first pseudo-random sequence to obtain a valid information frame and a pseudo information frame;

[0115] An information demodulation module is used for demodulating valid information frames at the receiving end through a matched filter and outputting demodulated information;

[0116] The information extraction module is used at the receiving end to sample and compare the demodulated information to obtain valid information.

[0117] Optionally, the information demodulation module is used to match the valid information frame with the local waveform sample through a matched filter and output demodulated information.

[0118] Optionally, also include:

[0119] A receiving end periodic control word generation module, used to generate a receiving end periodic control word based on a second pseudo-random sequence;

[0120] A receiving end target cycle determination module, used to determine a target cycle of the receiving end from a cycle set based on a cycle control word;

[0121] The local waveform sample generation module is used to select local waveform samples corresponding to the frequency modulation rate from the baseband waveform sample memory based on the target period.

[0122] Based on this, the device adopts a time jitter strategy to make the signal period between different symbols show pseudo-random jumps within a specified period set, thereby overcoming the problems of obvious signal characteristics and high detection probability in some period detection methods and period characteristic spectra; at the same time, a strategy for randomly interleaving user information and pseudo-information is designed. The transmitted information is no longer a single user information, but an information frame containing pseudo-information. The pseudo-information is also Chirp spread spectrum modulated at the sending end. Therefore, in an electromagnetic environment, even if the transmission signal is intercepted, the intercepting party cannot distinguish whether the intercepted information is useful or not because it does not know the framing method, thereby ensuring the security of communication between the two communicating parties, thereby solving the problem of weak concealment and weak anti-interception capability of the currently commonly used covert communication architecture.

[0123] Example 3

[0124] Please refer to Figure 8 , this embodiment provides an electronic device, which includes a processor, an internal bus, a network interface, a memory and a non-volatile memory, and of course may also include hardware required for other services. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, forming a time-jittered covert communication waveform design method at the logical level. Of course, in addition to the software implementation, this specification does not exclude other implementation methods, such as logic devices or a combination of software and hardware, etc., that is, the execution subject of the following processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0125] The network interface, processor and memory can be connected to each other through a bus system. The above bus can be divided into an address bus, a data bus, a control bus, etc.

[0126] The memory is used to store programs. Specifically, the program may include program code, and the program code includes computer operation instructions. The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor.

[0127] The processor is used to execute the program stored in the above memory, and specifically perform:

[0128] Step 102, based on the first pseudo-random sequence, combining the valid information with the pseudo-information to form modulated information;

[0129] Step 104, selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence;

[0130] Step 106, modulating the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal;

[0131] Step 108, up-convert the baseband modulated signal to generate a transmit signal which is transmitted from the transmitting end.

[0132] The processor may be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above method may be completed by an integrated logic circuit of the processor hardware or by instructions in the form of software.

[0133] Based on the same invention, the embodiment of this specification also provides a computer-readable storage medium, which stores one or more programs. When the one or more programs are executed by an electronic device including multiple application programs, the electronic device executes Figure 1-Figure 6 The corresponding embodiment provides a method for designing a covert communication waveform with time jitter.

[0134] Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems, or computer program products. Therefore, this specification may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this specification may take the form of a computer program product implemented on one or more computer-readable storage media containing computer-usable program code.

[0135] In addition, for the above-mentioned specific implementation of the system, since it is basically similar to the method implementation, the description is relatively simple, and the relevant parts can be referred to the partial description of the method implementation. Moreover, it should be noted that in each module of the system of the present application, the components therein are logically divided according to the functions to be implemented, but the present application is not limited thereto, and the components can be re-divided or combined as needed.

[0136] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences between it and other embodiments.

[0137] The above is a description of a specific embodiment of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the specific order or sequential order shown in the process depicted in the drawings is not necessarily required to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0138] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for designing a time-jittered covert communication waveform, characterized in that: include: Based on the first pseudo-random sequence, combining the valid information with the pseudo-information to form modulated information; Selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence; The Chirp signal, the baseband signal and the modulation information are modulated to generate a baseband modulation signal; The baseband modulated signal is up-converted to generate a transmit signal which is then transmitted from the transmitter.

2. The method according to claim 1, characterized in that The combining effective information and pseudo information based on the first pseudo-random sequence to form modulated information includes: Based on the first pseudo-random sequence, generating a random information selection control word; The control word is selected based on the random information to combine the effective information and the dummy information to generate the modulation information.

3. The method according to claim 2, characterized in that After the control word is selected based on random information to combine valid information and dummy information to generate modulation information, the method further includes: performing polarity conversion on the modulation information to obtain modulation information after polarity conversion.

4. The method according to claim 1, characterized in that: The method of selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence includes: Storing a plurality of Chirp signals with different cycle lengths in a baseband waveform sample memory; A period set is constructed based on the period of the Chirp signal in the baseband waveform sample memory.

5. The method according to claim 4, characterized in that The selecting a corresponding Chirp signal from the baseband waveform sample memory based on the second pseudo-random sequence comprises: Based on the second pseudo-random sequence, generating a period control word; Based on the mapping relationship between the cycle control word and the cycle set, determining the target cycle from the cycle set; Input the target period into the baseband waveform sample memory and output the corresponding Chirp signal.

6. The method according to claim 1, characterized in that After up-converting the baseband modulated signal to generate a transmit signal and transmitting it from the transmitting end, it also includes: The receiving end receives the transmitted signal to obtain a received signal; The receiving end performs frame processing on the received signal based on the first pseudo-random sequence to obtain a valid information frame and a pseudo information frame; The receiving end demodulates the valid information frame through a matched filter and outputs the demodulated information; The receiving end samples, compares and judges the demodulated information to obtain valid information.

7. The method according to claim 6, characterized in that The demodulating the effective information frame by using a matched filter and outputting the demodulated information comprises: matching the effective information frame with a local waveform sample by using a matched filter and outputting the demodulated information.

8. The method according to claim 7, characterized in that The receiving end demodulates the valid information frame by a matched filter, and before outputting the demodulated information, it also includes: Based on the second pseudo-random sequence, generating a periodic control word of the receiving end; Determining a target cycle of the receiving end from the cycle set based on the cycle control word; Based on the target period, a local waveform sample corresponding to the frequency modulation rate is selected from the baseband waveform sample memory.

9. A time-jittered covert communication waveform design device, characterized in that: include: A pseudo information interleaving module, used for combining effective information with pseudo information based on a first pseudo random sequence to form modulated information; A time domain random jitter module, used for selecting a corresponding Chirp signal from a baseband waveform sample memory based on a second pseudo-random sequence; A signal modulation module is used to modulate the Chirp signal, the baseband signal and the modulation information to generate a baseband modulation signal; The signal transmission module is used to up-convert the baseband modulated signal to generate a transmission signal and transmit it from the transmitting end.

10. An electronic device, characterized in that: include: processor; and a memory arranged to store computer executable instructions which, when executed, cause the processor to perform the steps of the method as claimed in any one of claims 1 to 8.

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