QPSK modulation-based radar-communication integrated system and waveform design method

Abstract

The application discloses a radar communication integrated system and waveform design method based on QPSK modulation, and relates to the technical field of communication, and comprises the following steps: sequentially encoding and modulating a communication signal generated by a signal source to obtain a modulated communication signal; modulating a radar signal to obtain a modulated radar signal; and mixing the modulated communication signal and the modulated radar signal to form an integrated signal; wherein the integrated signal is used for communication transmission and radar detection. The application can improve the frequency spectrum utilization rate and the system comprehensive performance.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, specifically relating to an integrated radar communication system and waveform design method based on QPSK modulation. Background Technology

[0002] With the rapid development of wireless communication and radar technologies, the competition for spectrum resources is becoming increasingly fierce. Traditional radar and communication systems operate independently, consuming a large amount of spectrum resources. To improve the utilization rate of spectrum resources, integrated radar and communication systems have become a research hotspot.

[0003] In existing research, radar and communication systems have largely been developed separately with distinct objectives. Radar systems are primarily used for target detection and tracking, while communication systems are mainly used for information transmission. With advancements in electronics, devices utilizing both radar and communication have been developed for various applications, such as intelligent transportation systems, which require environmental sensing and information transmission. Therefore, combined radar and communication systems offer advantages such as reduced system weight, size, and power consumption, and have gained significant traction in recent years.

[0004] To date, research on integrated radar-communication systems has fallen into two categories: non-simultaneous systems and simultaneous systems. In non-simultaneous systems, radar and communication functions operate in different time slots. While this is easy to implement, it introduces radar detection blind spots during communication, impacting communication performance. Conversely, simultaneous systems utilize a shared signal—an integrated radar-communication signal—which enables both target detection and information transmission. Currently, three methods exist for designing the "integrated" signal. First, radar and communication signals are generated independently and then superimposed. Second, communication data is modulated onto the radar signal. Third, the communication signal is designed as, for example, a multi-carrier signal; this method is considered the most promising, offering high performance in both radar detection and information transmission. However, existing integrated radar-communication systems suffer from high complexity, low spectral efficiency, and poor real-time performance. There is an urgent need to provide an integrated radar-communication system and its waveform design method to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides an integrated radar-communication system based on QPSK modulation and a waveform design method. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a waveform design method for a radar-communication integrated system based on QPSK modulation, comprising:

[0007] After the communication signal generated by the information source is encoded and modulated sequentially, the modulated communication signal is obtained;

[0008] The radar signal is modulated to obtain the modulated radar signal;

[0009] The modulated communication signal and the modulated radar signal are mixed to form an integrated signal; wherein the integrated signal is used for communication transmission and radar detection.

[0010] Secondly, the present invention also provides a radar-communication integrated system based on QPSK modulation, comprising:

[0011] A communication signal modulation device includes a signal source, a communication encoder, and a communication signal modulator. The output of the signal source is communicatively connected to the input of the communication encoder, and the output of the communication encoder is communicatively connected to the input of the communication signal modulator. The signal source is used to provide a communication signal, the communication encoder is used to encode the communication signal, and the communication signal modulator is used to modulate the encoded communication signal to obtain a modulated communication signal.

[0012] A radar signal modulation device, including a radar signal modulator, is used to modulate radar signals to obtain modulated radar signals;

[0013] A signal mixing unit, wherein the input terminal of the signal mixing unit is communicatively connected to the output terminals of the communication signal modulator and the radar signal modulator, respectively, for mixing the modulated communication signal and the modulated radar signal;

[0014] The first beamforming unit has its input terminal communicatively connected to the output terminal of the mixing unit, and is used to form an integrated signal from the mixed signal.

[0015] A transmitter, the input of which is communicatively connected to the output of the first beamforming unit, is used to transmit the integrated signal;

[0016] A duplexer, the input of which is communicatively connected to the output of the transmitter, is used to transmit the integrated signal into space for communication transmission and radar detection.

[0017] The beneficial effects of this invention are:

[0018] This invention provides an integrated radar-communication system and waveform design method based on QPSK modulation. By optimizing waveform design, it achieves effective fusion of radar detection and communication transmission, improving spectrum utilization and overall system performance. This invention has significant practical application value and broad application prospects. First, it fully utilizes the high power performance of radar transmission to extend the transmission distance of the communication system, enhances the anti-interference capability and signal transmission quality of the communication signal, and the directional nature of radar signals reduces the probability of signal interception, thereby improving communication security. Furthermore, the integrated system integrates data aggregation and processing within the same module, enabling information sharing, improving responsiveness to threats, and significantly increasing data exchange and processing speed, providing rapid response capabilities. Based on a comprehensive analysis of the transmission capabilities of radar detection and communication systems, an integrated radar-communication signal model is built, reducing equipment complexity and improving system integration and responsiveness. Facing increasingly complex environments, it further enhances information transmission and processing capabilities and strengthens comprehensive research on radar communication signals.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a radar system provided by existing technology;

[0021] Figure 2 This is a schematic diagram of a communication system provided by existing technology;

[0022] Figure 3 This is a schematic diagram of an integrated radar and communication system provided in an embodiment of the present invention;

[0023] Figure 4 This is a flowchart of a waveform design method for a radar-communication integrated system based on QPSK modulation provided in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of a Chirp signal provided in an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram illustrating the mixing of modulated communication signals and modulated radar signals according to an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram showing a comparison between the original signal and the integrated signal waveform provided in an embodiment of the present invention. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0028] In existing technologies, the joint design of radar and communication systems mainly includes the following methods:

[0029] First, Frequency Division Multiplexing (FDM) technology performs radar detection and communication transmission on different frequency bands. This method is simple and easy to implement, but its spectrum utilization is low and it cannot achieve spectrum resource sharing.

[0030] Second, Time Division Multiplexing (TDM) technology performs radar and communication in different time slots. This method allows for equipment sharing, but its real-time performance is poor, and it cannot perform radar detection and communication transmission simultaneously.

[0031] Third, code division multiplexing (CDM) technology uses different code sequences to achieve radar and communication functions separately. This method can improve spectrum utilization to some extent, but it suffers from significant inter-code interference and high system complexity.

[0032] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a radar system provided by existing technology. Figure 2 This is a schematic diagram of a communication system provided by existing technology. Figure 1 and Figure 2 Analysis reveals significant differences between radar and communication systems in terms of hardware and software architecture. However, from the perspective of information processing and transmission, there are aspects that can be learned from each other. A comparative analysis of their differences mainly focuses on:

[0033] First, radar systems cannot transmit and receive simultaneously; phased array radar systems are a typical example of half-duplex operation, which contradicts the transmission of communication system resources. Depending on different needs, communication systems can operate in various ways.

[0034] Secondly, there is a significant difference in bandwidth between radar systems and communication systems. For radar systems, in order to ensure that they have more accurate range resolution, the radar bandwidth must reach at least hundreds of megabits during operation. Generally speaking, the operating bandwidth of radar systems is much higher than that of communication systems, while the bandwidth of communication signals is generally lower during operation. Even with the 4G technology currently in use, the bandwidth of Orthogonal Frequency Division Multiplexing (OFDM) systems is maintained at tens of MHz.

[0035] Third, radar systems and communication systems differ in their signal waveform selection. Communication systems typically use continuous waves to ensure the reliability and stability of communication signals during transmission. Radar signal waveforms include pulse waveforms and linear frequency modulated signals. Currently, most radar signal waveforms are typical pulse patterns, while this invention proposes to use continuous wave signals, i.e., linear frequency modulated signals.

[0036] Fourth, there is a significant difference in transmission power between radar systems and communication systems. The transmission power corresponding to radar detection is much higher than that of current communication systems. Generally speaking, the working range of radar systems is much greater than that of communication systems. Its operation involves transmitting radar signals to a specific area, detecting the feedback of targets in the area, and returning the radar signals to the corresponding radar receiving module for further processing. The principle of communication systems is that the signal is transmitted by the transmitter, and the receiving end receives and processes the signal. In general, the distance between the transmitter and receiver in communication is relatively short. Therefore, in order to meet the functions of radar systems such as target search, location, tracking, and information acquisition, the transmission power of radar systems must be much higher than that of communication systems.

[0037] Fifth, communication systems and radar systems differ significantly in their operating frequency bands. Both have their primary frequency bands, with communication systems operating at significantly lower frequencies than radar systems. This is to prevent potential interference when both are used simultaneously. According to the International Telecommunication Union's allocation of available frequency bands, the signal frequency range currently used by communication systems is generally stable between 300MHz and 10GHz, with the most significant applications being ultra-high frequency (300MHz–3GHz) and some ultra-high frequency (3GHz–30GHz). In contrast, radar systems primarily operate in frequency bands above 300MHz, including ultra-high frequency, ultra-high frequency, and extremely high frequency (30GHz–300GHz). Therefore, radar systems occupy a relatively higher and more extensive frequency band compared to communication systems, and there is some overlap between the two.

[0038] By comparing and analyzing the similarities and differences between radar systems and communication systems, it can be concluded that they have many similarities, but also certain differences. Integrating and optimizing them can create a radar-communication integrated system, which can be elaborated on from the following aspects:

[0039] First, the radar system and the communication system share a common system architecture. They are very similar in hardware structure, and both include similar structural parts such as transmitters and antennas at the front end of transmission. Both receive signals through receivers. By sharing the same system, the system complexity is effectively reduced by the number of devices carried by multiple systems working together on the same platform. This is of great significance for reducing electromagnetic interference between various systems. Sharing part of the system architecture is the key to radar-communication integration.

[0040] Secondly, the signals of the radar system and the communication system can be separated and mixed. After receiving the integrated mixed signal, the system can separate it into radar signal and communication signal by means of signal separation. The signal after signal separation at the receiving end is returned to the radar and communication systems and processed by their respective hardware systems. The above method requires high separation accuracy to process the mixed signal. With the improvement of chip performance and the development of digital signal technology, the signal processing efficiency will be significantly improved.

[0041] Third, the radar system and the communication system can operate within the same frequency range. The International Telecommunication Union has already subdivided different frequency bands, and there is some overlap between the two systems across these bands. The frequency selection for the integrated system can be based on overlapping frequency band ranges. The frequency range to be selected in this invention is the ultra-high frequency (UHF) range. The foundation of radar-communication integration is to utilize the structural similarities of the two different systems, sharing the antennas, transmitters, and receivers of the transmitting and receiving parts of the radar and communication systems. Appropriate signal mixing processing is performed before signal transmission, and signal separation is achieved at the receiving end, thus obtaining the integrated system framework diagram. Please refer to [link to diagram]. Figure 3 , Figure 3 This is a schematic diagram of an integrated radar and communication system provided in an embodiment of the present invention.

[0042] In summary, the different signal processing techniques used in radar and communication systems can be fully implemented in software within their digital domains. After completing the integrated system architecture design, the corresponding integrated waveform needs to be designed. According to the integrated architecture diagram of this invention, a crucial task is to synthesize the integrated signal. After the signal is transmitted through the radar antenna, since the integrated signal carries both communication information and can be retrieved to achieve the basic function of target detection, a series of signal separation operations are required, whether the received signal returns to the onboard radar or the communication process after transmission. Through the signal separation module, the original integrated signal is further separated and processed to extract the detected target information. Simultaneously, after receiving the signal, the receiving device needs to send it to the subsequent communication signal processing module to extract the corresponding communication information. The integrated waveform signal must ensure both communication performance and meet the radar's detection requirements, making it the most important part of the integrated system.

[0043] Please see Figure 4 , Figure 4 This is a flowchart of a waveform design method for a radar-communication integrated system based on QPSK modulation provided in this invention. The waveform design method for a radar-communication integrated system based on QPSK modulation provided by this invention includes:

[0044] S101. The communication signal generated by the information source is encoded and modulated sequentially to obtain the modulated communication signal.

[0045] Specifically, in this embodiment, quadrature phase shift keying (QPSK) is used to modulate the communication signal. As one of the important modes of communication information modulation, QPSK is essentially a phase communication modulation process that can use certain coding conversion strategies to convert the baseband signal into a suitable channel form. QPSK signal modulation is achieved by loading corresponding phase information onto different communication information for modulation. The main goal of communication modulation is to improve spectrum utilization. However, in an integrated system, to cope with external interference, the modulation method should balance bandwidth resources and anti-interference capability. Although these two cannot be simultaneously achieved, considering the complexity of the integrated signal system, the system should meet the requirement of simplicity as much as possible during modulation and demodulation.

[0046] 1. Strong noise resistance;

[0047] Integrated signals inevitably encounter strong interference problems and complex battlefield environments during transmission. At this time, it is necessary to ensure sufficient communication performance under various clutter conditions and ensure that the integrated system communication error rate is low enough when facing complex external environments.

[0048] 2. It features low-computation signal modulation and demodulation methods;

[0049] To simplify the computational complexity of radar-communication integrated signals, it is necessary to ensure the simplicity of the signal modulation method during modulation and demodulation, thereby guaranteeing signal stability. Furthermore, it is also crucial to maximize spectrum utilization efficiency. The k-th symbol of the modulated communication signal can be represented as:

[0050]

[0051] Among them, S QPSK (t) represents the modulated communication signal, f c The carrier frequency is represented by t, and the time axis is represented by t. Indicates the initial phase.

[0052] S102. Modulate the radar signal to obtain the modulated radar signal.

[0053] Specifically, in this embodiment, linear frequency modulation (LFM) is used to modulate the radar signal. LFM signals, also represented by chirp signals, are a common signal mode in radar systems. Their advantages lie in their large time-bandwidth product, resulting in significant signal processing gain. A key characteristic is that they exhibit a linear decreasing and increasing relationship between time and frequency. The expression for the modulated radar signal is:

[0054]

[0055] Among them, S LFM (t) represents the modulated radar signal. Let f0 represent the starting frequency of the linear frequency modulated signal, t represent the time axis, K represent the frequency modulation efficiency, and T represent the duration.

[0056] Please see Figure 5 , Figure 5 This is a schematic diagram of a chirp signal provided in an embodiment of the present invention. Based on the sign of K, the LFM signal can be divided into ascending polarity (K>0) and descending polarity (K<0). See details in [link to relevant documentation]. Figure 5 The two subgraphs are (a) and (b).

[0057] S103. The modulated communication signal and the modulated radar signal are mixed to form an integrated signal; the integrated signal is used for communication transmission and radar detection.

[0058] Specifically, in this embodiment, based on QPSK single-carrier modulation, the carrier wave is converted into f after integrated waveform processing. c +f0+Kt 2 / 2, it is usually assumed that the starting frequency of the linear frequency modulated signal is zero, thus obtaining the corresponding k-th modulation symbol, the expression of which is:

[0059]

[0060] After trigonometric transformation, the expression of the integrated signal is updated to:

[0061]

[0062] Assuming the initial frequency of the linear frequency modulated signal is zero, the initial phase of the signal is... The QPSK-LFM signal has a frequency shift compared to the QPSK signal, but other aspects remain unchanged. The carrier frequency characteristics of the linear frequency modulation signal lead to a gradually denser integrated signal, but the baseband modulation of the communication signal does not need to be altered. Figure 6 For integrated signal mixing, please refer to [link / reference]. Figure 6 , Figure 6This is a schematic diagram illustrating the mixing of modulated communication signals and modulated radar signals according to an embodiment of the present invention, specifically:

[0063] The modulated communication signal is sequentially subjected to differential coding and serial-to-parallel conversion to obtain the first branch signal and the second branch signal, respectively;

[0064] The first branch signal is multiplied with the phase-shifted signal of the modulated communication signal to obtain the first processed signal; the first processed signal is multiplied with the modulated radar signal to obtain the first signal.

[0065] The second branch signal is multiplied with the phase-shifted signal of the modulated communication signal to obtain the second processed signal, and the second processed signal is multiplied with the modulated radar signal to obtain the second signal.

[0066] The first signal, the modulated radar signal, and the second signal are added together to obtain the integrated signal.

[0067] In this embodiment, the time-domain simulation results of the mixed communication signal and radar signal can be obtained through integrated signal simulation, specifically as follows:

[0068] Simulation settings: digital signal frequency 0.05MHz, K=300, results are as follows. Figure 7 As shown, please refer to Figure 7 , Figure 7 This is a schematic diagram showing a comparison between the original signal and the integrated signal waveform provided in an embodiment of the present invention. Figure 7 In the diagram, (a) represents an equal-probability binary digital signal, and (b) represents a QPSK-LFM signal. Figure 6 As shown, the original communication signal is QPSK modulated, and the original radar signal is linearly frequency modulated. The two are then mixed to obtain a QPSK-LFM integrated signal. Figure 7 Analysis of the time-domain waveforms shown reveals a slight overall change in waveform frequency, consistent with the gradually denser characteristics of LFM waveforms. This is because QPSK modulation is used, resulting in a continuous waveform frequency. The integrated signal in the time domain manifests as a QPSK signal within a linear frequency modulated signal envelope. By fusing the characteristics of these two waveforms, it satisfies the functional requirements of LFM radar while also supporting QPSK communication. Furthermore, using LFM as a carrier allows for data modulation, thereby achieving communication. The integrated signal retains its overall linear frequency modulated properties.

[0069] In summary, this invention provides a waveform design method for an integrated radar-communication system based on QPSK modulation. By optimizing the waveform design, it effectively integrates radar detection and communication transmission, improving spectrum utilization and overall system performance. This invention has significant practical application value and broad application prospects. First, it fully utilizes the high power performance of radar transmission to extend the transmission distance of the communication system, enhances the anti-interference capability and signal transmission quality of the communication signal, and the directional nature of radar signals reduces the probability of signal interception, thereby improving communication security. Furthermore, the data aggregation and processing in the entire integrated system are handled within the same module, enabling information sharing, improving responsiveness to threats, and significantly increasing data exchange and processing speed, providing rapid response capabilities. Based on a comprehensive analysis of the transmission capabilities of radar detection and communication systems, an integrated radar-communication signal model is built, reducing equipment complexity and improving system integration and responsiveness. Facing increasingly complex environments, it further enhances information transmission and processing capabilities and strengthens comprehensive research on radar communication signals.

[0070] Based on the same inventive concept, please continue to see Figure 3 The present invention also provides a radar-communication integrated system based on QPSK modulation. Using the integrated waveform provided in the above embodiments of the present invention, the radar-communication integrated system is realized. The integrated waveform design method is described above and will not be repeated here. The radar-communication integrated system includes:

[0071] A communication signal modulation device includes a signal source, a communication encoder, and a communication signal modulator. The output of the signal source is communicatively connected to the input of the communication encoder, and the output of the communication encoder is communicatively connected to the input of the communication signal modulator. The signal source is used to provide a communication signal, the communication encoder is used to encode the communication signal, and the communication signal modulator is used to modulate the encoded communication signal to obtain a modulated communication signal.

[0072] A radar signal modulation device, including a radar signal modulator, is used to modulate radar signals to obtain modulated radar signals;

[0073] A signal mixing unit, wherein the input terminal of the signal mixing unit is communicatively connected to the output terminals of the communication signal modulator and the radar signal modulator, respectively, for mixing the modulated communication signal and the modulated radar signal;

[0074] The first beamforming unit has its input terminal communicatively connected to the output terminal of the mixing unit, and is used to form an integrated signal from the mixed signal.

[0075] A transmitter, the input of which is communicatively connected to the output of the first beamforming unit, is used to transmit the integrated signal;

[0076] A duplexer, the input of which is communicatively connected to the output of the transmitter, is used to transmit the integrated signal into space for communication transmission and radar detection.

[0077] In an optional embodiment of the present invention, please continue to refer to... Figure 3 It also includes:

[0078] A receiver, the input of which is communicatively connected to the output of the duplexer, is used to receive echo signals and / or communication signals;

[0079] The second beamforming unit, whose input terminal is communicatively connected to the output terminal of the receiver, is used to convert the echo signal and / or communication signal into a signal to be processed.

[0080] A signal separation unit, wherein the input end of the signal separation unit is communicatively connected to the output end of the second beamforming unit, is used to separate the signal to be processed;

[0081] A radar signal processor, wherein the input terminal of the radar signal processor is communicatively connected to the output terminal of the signal separation unit;

[0082] A communication signal processor, wherein the input terminal of the communication signal processor is communicatively connected to the output terminal of the radar signal processor;

[0083] When the signal to be processed is separated, it includes radar information and is displayed on the display; when the signal to be processed is separated, it includes communication information and is stored by the receiver.

[0084] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0085] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0086] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A waveform design method for a radar-communication integrated system based on QPSK modulation, characterized in that, include: After the communication signal generated by the information source is encoded and modulated sequentially, the modulated communication signal is obtained; The radar signal is modulated to obtain the modulated radar signal; The modulated communication signal and the modulated radar signal are mixed to form an integrated signal; wherein, the integrated signal is used for communication transmission and radar detection. The process of mixing the modulated communication signal and the modulated radar signal to form an integrated signal includes: The modulated communication signal is sequentially subjected to differential coding and serial-to-parallel conversion to obtain the first branch signal and the second branch signal, respectively; Phase shifting of the first branch signal and the modulated communication signal The signal after being divided by 2 is multiplied to obtain the first processed signal; the first processed signal is multiplied with the modulated radar signal to obtain the first signal. Phase shifting of the second branch signal and the modulated communication signal The signal after being divided by 2 is multiplied to obtain the second processed signal. The second processed signal is then multiplied with the modulated radar signal to obtain the second signal. The first signal, the modulated radar signal, and the second signal are added together to obtain the integrated signal.

2. The waveform design method for the radar-communication integrated system based on QPSK modulation according to claim 1, wherein the expression of the integrated signal is: ； After trigonometric transformation, the expression of the integrated signal is updated as follows: ； in, Indicates an integrated signal. Indicates the starting phase of the modulated communication signal. Indicates the carrier frequency. Represents the timeline. This indicates the frequency modulation efficiency.

3. The waveform design method for a radar-communication integrated system based on QPSK modulation according to claim 1, characterized in that, The expression for the modulated communication signal is: ； in, This represents the modulated communication signal. Indicates the carrier frequency. Represents the timeline. Indicates the initial phase.

4. The waveform design method for a radar-communication integrated system based on QPSK modulation according to claim 1, characterized in that, The process of sequentially encoding and modulating the communication signal generated by the information source to obtain the modulated communication signal includes: Intersecting phase-shift keys are used to modulate the communication signals.

5. The waveform design method for a radar-communication integrated system based on QPSK modulation according to claim 1, characterized in that, The expression for the modulated radar signal is: ； ； in, This represents the modulated radar signal. Represents a rectangular signal. This indicates the starting frequency of the linear frequency modulated signal. Represents the timeline. Indicates frequency modulation efficiency. Indicates duration.

6. The waveform design method for a radar-communication integrated system based on QPSK modulation according to claim 1, characterized in that, The process of modulating the radar signal to obtain the modulated radar signal includes: Linear frequency modulation is used to modulate the radar signal.

7. A radar-communication integrated system based on QPSK modulation, characterized in that, include: A communication signal modulation device includes a signal source, a communication encoder, and a communication signal modulator. The output of the signal source is communicatively connected to the input of the communication encoder, and the output of the communication encoder is communicatively connected to the input of the communication signal modulator. The signal source is used to provide a communication signal, the communication encoder is used to encode the communication signal, and the communication signal modulator is used to modulate the encoded communication signal to obtain a modulated communication signal. A radar signal modulation device, including a radar signal modulator, is used to modulate radar signals to obtain modulated radar signals; A signal mixing unit, wherein the input terminal of the signal mixing unit is communicatively connected to the output terminals of the communication signal modulator and the radar signal modulator, respectively, for mixing the modulated communication signal and the modulated radar signal; The first beamforming unit has its input terminal communicatively connected to the output terminal of the mixing unit, and is used to form an integrated signal from the mixed signal. A transmitter, the input of which is communicatively connected to the output of the first beamforming unit, is used to transmit the integrated signal; A duplexer, the input of which is communicatively connected to the output of the transmitter, is used to transmit the integrated signal into space for communication transmission and radar detection. The process of forming a unified signal from the mixed signals includes: The modulated communication signal is sequentially subjected to differential coding and serial-to-parallel conversion to obtain the first branch signal and the second branch signal, respectively; Phase shifting of the first branch signal and the modulated communication signal The signal after being divided by 2 is multiplied to obtain the first processed signal; the first processed signal is multiplied with the modulated radar signal to obtain the first signal. Phase shifting of the second branch signal and the modulated communication signal The signal after being divided by 2 is multiplied to obtain the second processed signal. The second processed signal is then multiplied with the modulated radar signal to obtain the second signal. The first signal, the modulated radar signal, and the second signal are added together to obtain the integrated signal.

8. The radar-communication integrated system based on QPSK modulation according to claim 7, characterized in that, Also includes: A receiver, the input of which is communicatively connected to the output of the duplexer, is used to receive echo signals and / or communication signals; The second beamforming unit, whose input terminal is communicatively connected to the output terminal of the receiver, is used to convert the echo signal and / or communication signal into a signal to be processed. A signal separation unit, wherein the input end of the signal separation unit is communicatively connected to the output end of the second beamforming unit, is used to separate the signal to be processed; A radar signal processor, wherein the input terminal of the radar signal processor is communicatively connected to the output terminal of the signal separation unit; A communication signal processor, wherein the input terminal of the communication signal processor is communicatively connected to the output terminal of the radar signal processor; When the signal to be processed is separated, it includes radar information and is displayed on the display; when the signal to be processed is separated, it includes communication information and is stored by the receiver.

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