Radar communication integrated system based on QPSK modulation and waveform design method

Abstract

The invention discloses a radar communication integrated system based on QPSK modulation and a waveform design method, and relates to the technical field of communication, and the method comprises the steps: carrying out the coding and modulation of a communication signal generated by an information source, and obtaining a modulated communication signal; modulating the radar signal to obtain a modulated radar signal; performing signal mixing on 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 spectrum utilization rate and the comprehensive performance of the system can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of communication, and in particular relates to a radar communication integrated system based on QPSK modulation and a waveform design method. Background Art

[0002] With the rapid development of wireless communication and radar technology, the competition for spectrum resources has become increasingly fierce. Traditional radar systems and communication systems operate independently, occupying a large amount of spectrum resources. In order to improve the utilization of spectrum resources, the integrated radar and communication system has become a research hotspot.

[0003] In existing research, most radar and communication are developed separately with different goals. Radar systems are mainly used to detect and track targets, while communication systems are mainly used for information transmission. With the advancement of electronic technology, a device that uses both radar and communication has developed a variety of applications, such as intelligent transportation systems, which need to sense the environment and transmit information. Therefore, the joint radar communication system can enjoy the advantages of reducing system weight, size, power consumption, etc., and has gained a lot in recent years.

[0004] So far, the research on communication radar integrated system is divided into two categories: non-simultaneous system and simultaneous system. For non-simultaneous system, radar and communication functions operate in different time slots. Although it is easy to implement, there is a radar detection blind spot during the communication process, which affects the communication performance. In contrast, the simultaneous system uses a shared signal, that is, a communication radar integrated signal, which can achieve both target detection and information transmission functions. At present, there are three methods for designing "integrated" signals. First, radar and communication signals are generated independently and then superimposed; second, communication data is modulated on the radar signal; third, the communication signal is designed as a multi-carrier signal, for example. This method is considered to be the most promising one and can provide high performance in radar detection and information transmission. However, the existing radar communication integrated system has problems such as high complexity, low spectrum utilization, and poor real-time performance. It is urgent to provide a radar communication integrated system and a waveform design method thereof to improve the defects of the existing technology. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a radar communication integrated system based on QPSK modulation and a waveform design method. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[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] The communication signal generated by the information source is encoded and modulated in sequence to obtain a modulated communication signal;

[0008] modulating the radar signal to obtain a 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] In a second aspect, the present invention further provides a radar communication integrated system based on QPSK modulation, comprising:

[0011] A communication signal modulation device, comprising a signal source, a communication encoder and a communication signal modulator, wherein an output end of the signal source is communicatively connected to an input end of the communication encoder, an output end of the communication encoder is communicatively connected to an input end 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, for modulating a radar signal to obtain a modulated radar signal;

[0013] a signal mixing unit, wherein an input end of the signal mixing unit is communicatively connected to output ends of the communication signal modulator and the radar signal modulator, respectively, and is used to mix the modulated communication signal and the modulated radar signal;

[0014] a first beamforming unit, wherein an input end of the first beamforming unit is communicatively connected to an output end of the mixing unit, and is used to form a mixed signal into an integrated signal;

[0015] a transmitter, wherein an input end of the transmitter is communicatively connected to an output end of the first beamforming unit, and is used to transmit the integrated signal;

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

[0017] Beneficial effects of the present invention:

[0018] The present invention provides a radar communication integrated system based on QPSK modulation and a waveform design method. By optimizing the waveform design, the effective integration of radar detection and communication transmission is realized, and the spectrum utilization rate and the comprehensive performance of the system are improved. The present invention has important practical application value and broad application prospects. First, it can make full use of the high-power performance of radar transmission to improve the transmission distance of the communication system, improve the anti-interference ability of the communication signal and the signal transmission quality. Moreover, the radar transmission signal is directional, and the directional transmission reduces the probability of the communication signal being intercepted, thereby improving the communication security. In addition, the information aggregation and processing of data in the entire integrated system are under the same module, so that information sharing is realized, the resilience in the face of threats is improved, the data exchange and processing speed are greatly improved, and the rapid response capability can be provided. Based on the comprehensive analysis of the transmission capability of radar detection and communication system, a radar communication integrated signal model is built to reduce the complexity of equipment and improve the system integration and resilience; in the face of increasingly complex environments, the information transmission and processing capabilities are further improved, and the comprehensive research on radar communication signals is strengthened.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a radar system provided by the prior art;

[0021] Figure 2 It is a schematic diagram of a communication system provided by the prior art;

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

[0023] Figure 4 It is a flow chart of a waveform design method of a radar communication integrated system based on QPSK modulation provided by an embodiment of the present invention;

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

[0025] Figure 6 is a schematic diagram of mixing a modulated communication signal and a modulated radar signal provided by an embodiment of the present invention;

[0026] Figure 7 It is a schematic diagram of the comparison between the original signal and the integrated signal waveform provided by an embodiment of the present invention. DETAILED DESCRIPTION

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

[0028] In the prior art, there are several main methods for joint design of radar and communication, including:

[0029] First, frequency division multiplexing (FDM) technology, which performs radar detection and communication transmission in different frequency bands. This method is simple and easy to implement, but the spectrum utilization rate is low and spectrum resources cannot be shared.

[0030] Second, time division multiplexing (TDM) technology, radar and communication are performed in different time slots. This method can realize equipment sharing, but the real-time performance is poor and radar detection and communication transmission cannot be performed simultaneously.

[0031] Third, code division multiplexing (CDM) technology uses different code sequences to realize radar and communication functions respectively. This method can improve spectrum utilization to a certain extent, but the inter-code interference is large and the system complexity is high.

[0032] See also Figure 1 and Figure 2 , Figure 1 It is a schematic diagram of a radar system provided by the prior art. Figure 2 It is a schematic diagram of a communication system provided by the prior art. Figure 1 and Figure 2 The analysis shows that the radar system and the communication system have significant differences in hardware and software architecture. However, from the perspective of information processing and transmission, there are corresponding reference points between the two. The differences between the two are mainly reflected in:

[0033] First, the radar system cannot transmit and receive at the same time; among them, the phased array radar system is a typical half-duplex working mode, which is inconsistent with the transmission of communication system resources. According to different needs, the communication system can have multiple working modes.

[0034] Second, there is a significant difference in bandwidth between radar systems and communication systems. To ensure that radar systems have more accurate distance resolution, the radar bandwidth must be at least hundreds of megabytes when they are working. Generally speaking, the operating bandwidth of radar systems far exceeds that of communication systems, and when communication systems are working, the bandwidth of communication signals is generally lower. Even with the currently used 4G technology, the bandwidth is maintained at tens of MHz under the orthogonal frequency division multiplexing (OFDM) system.

[0035] Third, radar systems and communication systems differ in the selection of signal waveforms; the signal waveform commonly used in communication systems is a continuous wave, which ensures the reliability and stability of communication signals during transmission; radar signal waveform types include pulse waveforms and linear frequency modulation signals. Currently, most radar signal waveforms are typical pulse patterns, while the invention intends to use continuous wave signals, namely linear frequency modulation signals.

[0036] Fourth, there is a large gap in transmission power between radar systems and communication systems; the transmission function corresponding to the radar detection function is much higher than that of the current communication system. Generally speaking, the working distance of the radar system is much greater than that of the communication system. Its working method is to transmit radar signals to a specific area through a transmitter, detect the feedback of regional targets, and return the signal transmitted by the radar to the corresponding radar receiving module for corresponding processing. The principle of the communication system is that the signal is transmitted by the transmitter, and the receiving end receives the signal through the receiver for processing. In general, the distance between the communication transmitter and the receiver is relatively close. Therefore, in order to meet the radar system's functions of target search, positioning, tracking, and information acquisition, the radar system's transmission power is much higher than the communication system's transmission power.

[0037] Fifth, there are significant differences between communication systems and radar systems in terms of operating frequency bands. Both have their own main frequency bands, and the communication system frequency band is significantly lower than the radar system frequency band in order to prevent interference between the two when used at the same time. According to the International Telecommunication Union's division of available frequency bands, the current communication system's main signal frequency band range is basically stable at 300MHz to 10GHz, with the most important applications being UHF (300MHz~3GHz) and some UHF (3GHz~30GHz). The main frequency bands of current radar systems are concentrated in the frequency domain above 300MHz, namely UHF, UHF and EHF (30GHz~300GHz) and above. Therefore, the radar system occupies relatively higher and more frequency bands than the communication system, and the two overlap to a certain extent.

[0038] By comparing and analyzing the similarities and differences between radar systems and communication systems, it can be concluded that there are many similarities between the two, but there are also certain differences. By integrating and optimizing the two, a radar communication integrated system can be realized, which can be specifically developed from the following aspects:

[0039] First, the radar system and the communication system have a common system structure; the two have great similarities in hardware structure. Both include similar structural parts such as transmitters and antennas at the front end of the transmission, and both receive signals through receivers. By sharing the same system, the two effectively reduce the number of devices carried by multiple systems on the same platform in terms of system complexity, which is of great significance for reducing the electromagnetic interference problem between various systems. Sharing part of the system structure is the key to the integration of radar communications.

[0040] Second, the signals of the radar system and the communication system can be separated and mixed; after receiving the integrated mixed signal, the system can use signal separation to make it into radar signal and communication signal. After the signal separation is completed at the receiving end, the signal returns to the radar and communication system again, and is processed accordingly by their respective hardware systems. The above method needs to process the mixed signal, which requires high separation accuracy. After the chip performance is improved, coupled with the development of digital signal technology, the signal processing efficiency will be significantly improved.

[0041] Third, the operating frequencies of the radar system and the communication system can be selected in the same range; the International Telecommunication Union has currently subdivided different frequency bands, and there is a certain degree of commonality between the two in different frequency bands. The frequency selection of the integrated system can be based on the overlapping frequency band range. The frequency band range to be selected in the present invention is within the UHF range. The basis of radar and communication integration is to use the similarities in the structures of the two different systems, share the antennas, transmitters, and receivers of the transmitting and receiving parts of the radar and communication systems, perform corresponding mixed signal processing before signal transmission, and promote signal separation at the receiving end, thereby obtaining an integrated system framework diagram, please refer to Figure 3 , Figure 3 It is a schematic diagram of a radar communication integrated system provided by an embodiment of the present invention.

[0042] In summary, the different signal processing technologies of radar systems and communication systems can be completely implemented by software in their digital domain. After completing the integrated system structure design, the corresponding integrated waveform needs to be designed. According to the integrated structure diagram of the present invention, its important work is to synthesize the integrated signal. After the above signal is transmitted through the radar antenna, since the integrated signal not only carries the communication information, but also can be recovered by the signal to realize the basic function of detecting the target, whether it is the received signal returned to the onboard radar or the communication process after the transmission, a series of signal separation work is required. Through the signal separation module, the original integrated signal is separated and processed again, and then the detected target information is extracted. At the same time, 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 not only ensure the communication performance but also meet the detection requirements of the radar, and is the most important part of the integrated system.

[0043] See also Figure 4 , Figure 4 The present invention provides a flowchart of a waveform design method for a radar communication integrated system based on QPSK modulation, which includes:

[0044] S101. Encode and modulate a communication signal generated by a signal source in sequence to obtain a modulated communication signal.

[0045] Specifically, in this embodiment, the communication signal is modulated by using an intersecting phase shift key. As one of the important modes of communication information modulation, the core of quadrature phase shift keying (QPSK) is a phase communication modulation process, which can use a certain coding conversion strategy to convert the baseband signal into a suitable channel form. The realization of QPSK signal modulation is a process of modulating different communication information by loading corresponding phase information. The main goal of communication modulation is to improve the utilization of the spectrum through modulation. However, in an integrated system, in order to cope with external interference problems, the modulation method should take into account both frequency band resources and anti-interference capabilities. Although the two cannot be taken into account at the same time, considering the complexity of the integrated signal system, the system should meet simple requirements as much as possible during the modulation and demodulation process.

[0046] 1. Strong anti-noise ability;

[0047] The integrated signal will inevitably encounter strong interference problems and complex battlefield environments during the transmission process. At this time, it is necessary to ensure sufficient communication performance in the face of various clutter conditions, and to ensure that the integrated system communication bit error rate is low enough when facing complex external environments.

[0048] 2. Signal modulation and demodulation methods with low computational effort;

[0049] In order to simplify the computational complexity of the radar communication signal, it is necessary to consider keeping the signal modulation method as simple as possible in the modulation and demodulation of the signal, so as to ensure the stability of the signal performance. On this basis, it is also necessary to consider improving the spectrum utilization efficiency as much as possible. The kth code element of the modulated communication signal can be expressed as:

[0050]

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

[0052] S102: modulate the radar signal to obtain a modulated radar signal.

[0053] Specifically, in this embodiment, linear frequency modulation is used to modulate the radar signal. The linear frequency modulation (LFM) signal, which can also be represented by a Chirp signal, is a common signal mode of the radar system. Its advantage is that the "time bandwidth product" is large, and the signal processing has a large gain. The characteristic is that it shows a linear decreasing and increasing relationship between time and frequency. The expression of the modulated radar signal is:

[0054]

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

[0056] See also Figure 5 , Figure 5 is a schematic diagram of a Chirp signal provided in an embodiment of the present invention. According to the positive or negative value of K, the LFM signal can be divided into an ascending polarity (K>0) and a degrading polarity (K<0). For details, see Figure 5 There are two sub-graphs (a) and (b).

[0057] S103, mixing the modulated communication signal with the modulated radar signal to form an integrated signal; wherein the integrated signal is used for communication transmission and radar detection.

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

[0059]

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

[0061]

[0062] Assume that the starting frequency of the linear frequency modulation signal is zero and the starting phase of the signal is The QPSK-LFM signal has a frequency shift compared to the QPSK signal, and other aspects have not changed. The carrier frequency characteristics of the linear frequency modulation signal lead to the gradually dense characteristics of the integrated signal, but the baseband modulation of the communication signal does not need to be changed, so the realization Figure 6 For integrated signal mixing, see Figure 6 , Figure 61 is a schematic diagram of mixing a modulated communication signal and a modulated radar signal provided by an embodiment of the present invention, specifically:

[0063] The modulated communication signal is differentially encoded and serial-to-parallel converted in sequence to obtain a first branch signal and a second branch signal respectively;

[0064] Multiplying the first branch signal with the phase-shifted signal of the modulated communication signal to obtain a first processed signal; multiplying the first processed signal with the modulated radar signal to obtain a first signal;

[0065] Multiplying the second branch signal with the phase-shifted signal of the modulated communication signal to obtain a second processed signal, and multiplying the second processed signal with the modulated radar signal to obtain a 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 integrated signal simulation can obtain the time domain simulation result of the data after the communication signal and the radar signal are mixed, which is specifically:

[0068] Simulation condition settings: digital signal frequency is 0.05MHz, K=300, the results are as follows Figure 7 As shown, see Figure 7 , Figure 7 is a schematic diagram of the comparison between the original signal and the integrated signal waveform provided by an embodiment of the present invention, Figure 7 (a) is an isomeric binary digital signal, (b) is a QPSK-LFM signal, combined Figure 6 As shown in the figure, after the original communication signal is modulated by QPSK, the original radar signal is modulated by linear frequency modulation signal, and the two are mixed to obtain QPSK-LFM integrated signal. Figure 7 From the analysis of the time domain waveform shown in the figure, it can be seen that the overall waveform frequency has changed slightly, and it can match the gradually dense properties of the LFM waveform, because the frequency of the QPSK modulation waveform used is continuous. The time domain performance of the integrated signal is that the QPSK signal under the envelope of the linear frequency modulation signal can meet the requirements of the LFM radar function by integrating the characteristics of the two waveforms, and can also support the QPSK communication function. In addition, using LFM as a carrier can achieve certain data modulation, thereby realizing the communication function, and the integrated signal can still have the linear frequency modulation properties as a whole.

[0069] In summary, the waveform design method of a radar communication integrated system based on QPSK modulation provided by the present invention realizes the effective integration of radar detection and communication transmission by optimizing the waveform design, and improves the spectrum utilization rate and the overall performance of the system. The present invention has important practical application value and broad application prospects. First of all, it can make full use of the high-power performance of radar transmission to improve the transmission distance of the communication system, improve the anti-interference ability of the communication signal and the signal transmission quality, and the radar transmission signal is directional, and the directional transmission reduces the probability of the communication signal being intercepted, thereby improving the communication security. And in the entire integrated system, the information aggregation and processing of data are under the same module, and information sharing is realized, which improves the resilience in the face of threats, greatly improves the data exchange and processing speed, and can provide a rapid response capability. Based on the comprehensive analysis of the transmission capabilities of radar detection and communication systems, a radar communication integrated signal model is built to reduce the complexity of equipment and improve system integration and resilience. In the face of increasingly complex environments, the information transmission and processing capabilities are further improved, and the comprehensive research on radar communication signals is strengthened.

[0070] Based on the same invention concept, please continue to refer to Figure 3 The present invention also provides a radar communication integrated system based on QPSK modulation, using the integrated waveform provided by the above embodiment of the present invention to realize the radar communication integrated system. The integrated waveform design method is referred to above and will not be described in detail here. The radar communication integrated system includes:

[0071] A communication signal modulation device, comprising a signal source, a communication encoder and a communication signal modulator, wherein an output end of the signal source is communicatively connected to an input end of the communication encoder, an output end of the communication encoder is communicatively connected to an input end 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, for modulating a radar signal to obtain a modulated radar signal;

[0073] a signal mixing unit, wherein an input end of the signal mixing unit is communicatively connected to output ends of the communication signal modulator and the radar signal modulator, respectively, and is used to mix the modulated communication signal and the modulated radar signal;

[0074] a first beamforming unit, wherein an input end of the first beamforming unit is communicatively connected to an output end of the mixing unit, and is used to form a mixed signal into an integrated signal;

[0075] a transmitter, wherein an input end of the transmitter is communicatively connected to an output end of the first beamforming unit, and is used to transmit the integrated signal;

[0076] A duplexer, the input end of the duplexer is communicatively connected to the output end of the transmitter, and 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 , also includes:

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

[0079] a second beamforming unit, wherein an input end of the second beamforming unit is communicatively connected to an output end of the receiver, and is used for converting the echo signal and / or the communication signal into a signal to be processed;

[0080] a signal separation unit, wherein an input end of the signal separation unit is communicatively connected to an output end of the second beam forming unit, and is used to separate the signal to be processed;

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

[0082] a communication signal processor, wherein an input end of the communication signal processor is communicatively connected to an output end of the radar signal processor;

[0083] When the separated signal includes radar information, it is displayed by the display; when the separated signal includes communication information, it is stored by the sink.

[0084] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0086] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A waveform design method for a radar communication integrated system based on QPSK modulation, characterized in that: include: The communication signal generated by the information source is encoded and modulated in sequence to obtain a modulated communication signal; modulating the radar signal to obtain a 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.

2. The waveform design method of the radar communication integrated system based on QPSK modulation according to claim 1 is characterized in that: The step of mixing the modulated communication signal with the modulated radar signal to form an integrated signal includes: The modulated communication signal is differentially encoded and serial-to-parallel converted in sequence to obtain a first branch signal and a second branch signal respectively; Multiplying the first branch signal with the modulated communication signal after phase shift by π / 2 to obtain a first processed signal; multiplying the first processed signal with the modulated radar signal to obtain a first signal; Multiplying the second branch signal with the modulated communication signal after phase shift by π / 2 to obtain a second processed signal, and multiplying the second processed signal with the modulated radar signal to obtain a second signal; The first signal, the modulated radar signal and the second signal are added together to obtain the integrated signal.

3. According to the waveform design method of the radar communication integrated system based on QPSK modulation according to claim 1, the expression of the integrated signal is: After trigonometric transformation, the expression of the integrated signal is updated as follows: in, S k (t) represents the integrated signal, Indicates the starting phase of the modulated communication signal, f c represents the carrier frequency, t represents the time axis, and K represents the frequency modulation efficiency.

4. The waveform design method of the radar communication integrated system based on QPSK modulation according to claim 1 is characterized in that: The expression of the modulated communication signal is: Among them, S QPSK (t) represents the modulated communication signal, f c represents the carrier frequency, t represents the time axis, Indicates the initial phase.

5. The waveform design method of the radar communication integrated system based on QPSK modulation according to claim 1 is characterized in that: The communication signal generated by the information source is encoded and modulated in sequence to obtain a modulated communication signal, including: The communication signal is modulated using cross phase shift keying.

6. The waveform design method of the radar communication integrated system based on QPSK modulation according to claim 1 is characterized in that: The expression of the modulated radar signal is: Among them, S LFM (t) represents the modulated radar signal, represents a rectangular signal, f0 represents the starting frequency of the linear frequency modulation signal, t represents the time axis, K represents the frequency modulation efficiency, and T represents the duration.

7. The waveform design method of the radar communication integrated system based on QPSK modulation according to claim 1 is characterized in that: The step of modulating the radar signal to obtain a modulated radar signal includes: The radar signal is modulated using linear frequency modulation.

8. A radar communication integrated system based on QPSK modulation, characterized in that: include: A communication signal modulation device, comprising a signal source, a communication encoder and a communication signal modulator, wherein an output end of the signal source is communicatively connected to an input end of the communication encoder, an output end of the communication encoder is communicatively connected to an input end 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, for modulating a radar signal to obtain a modulated radar signal; a signal mixing unit, wherein an input end of the signal mixing unit is communicatively connected to output ends of the communication signal modulator and the radar signal modulator, respectively, and is used to mix the modulated communication signal and the modulated radar signal; a first beamforming unit, wherein an input end of the first beamforming unit is communicatively connected to an output end of the mixing unit, and is used to form a mixed signal into an integrated signal; a transmitter, wherein an input end of the transmitter is communicatively connected to an output end of the first beamforming unit, and is used to transmit the integrated signal; A duplexer, the input end of the duplexer is communicatively connected to the output end of the transmitter, and is used to transmit the integrated signal into space for communication transmission and radar detection.

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

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