阅读说明：本技术 脉冲多普勒雷达探通一体化波形设计方法 (Pulse Doppler radar sounding integrated waveform design method ) 是由 李向阳 李贵 郭花增 于 2020-12-25 设计创作，主要内容包括：本发明公开是一种脉冲多普勒雷达探通一体化波形设计方法,具有隐蔽通信和较好的精度。通过如下技术方案实现：利用脉冲多普勒雷达重复周期的有意调制,通过脉组间重复频率的变化来实现信息调制和时间同步；通信接收机把嵌在宽带噪声中的OFDM频谱截取出来,通过提取参数实现数据的解调,接收机发射波形在数据响应脉冲段,将发射信号落在探测雷达的处理时间窗口内,对帧同步脉冲段的脉冲进行脉冲组M2重复周期的估计和起始位置的同步,实现探测雷达与接收终端反向异步数据传输,随后,预测数据相应脉冲段脉冲位置及相应处理时间窗口。接收终端在信号接收过程中,利用信号处理设备提取信息,从硬件和波形方面进行基于雷达通信一体化的融合。(The invention discloses a pulse Doppler radar sounding integrated waveform design method, which has the advantages of covert communication and better precision. The method is realized by the following technical scheme: the information modulation and the time synchronization are realized by the change of the repetition frequency among pulse groups by utilizing the intentional modulation of the repetition period of the pulse Doppler radar; the communication receiver intercepts OFDM frequency spectrum embedded in broadband noise, realizes data demodulation by extracting parameters, transmits a waveform in a data response pulse section, enables a transmission signal to fall in a processing time window of a detection radar, carries out estimation of a pulse group M2 repetition period and synchronization of an initial position on pulses of a frame synchronization pulse section, realizes reverse asynchronous data transmission between the detection radar and a receiving terminal, and then predicts the pulse position of the corresponding pulse section of the data and the corresponding processing time window. And in the signal receiving process, the receiving terminal extracts information by using the signal processing equipment and performs integration based on radar communication from the aspects of hardware and waveform.)

1. A pulse Doppler radar sounding integrated waveform design method is characterized by comprising the following steps: the detection radar and the receiving terminal carry out data transmission communication information of both parties in a two-way communication modulation mode, the communication information is modulated by frequency points of a carrier, and information modulation and time synchronization are realized by utilizing the intentional modulation of a pulse Doppler radar repetition period and the change of repetition frequency among pulse groups; in time t, radar emission waveforms are transmitted for the Mth time to form a pulse group M2, and transmitted for the Nth time to form a pulse group N1 and a pulse group N2, a communication receiver intercepts an OFDM frequency spectrum embedded in broadband noise, then demodulation processing is carried out, echo of the whole signal is used for processing, target information is extracted, an electromagnetic wave is emitted by an antenna through the transmitter, and a receiving end receives the signal transmitted through a channel; the pulse group N1 and the pulse group M2 carry out a synchronization mechanism in a frame synchronization pulse section, a receiver identifies and preprocesses an address after receiving data, increases the number of sub-pulses of a group of sequences, realizes data demodulation by extracting parameters, modulates communication data into an integrated signal, transmits a waveform by a receiver, falls a transmitted signal in a processing time window of a detection radar in a data response pulse section, carries out estimation of a pulse group M2 repetition period and synchronization of an initial position on the pulse of the frame synchronization pulse section to realize reverse asynchronous data transmission of the detection radar and a receiving terminal, then predicts the pulse position of the corresponding pulse section of the data and the corresponding processing time window, transmits a specific pulse at a fixed position in the time window, analyzes symbol change of a transmitting terminal after pulse position information is obtained through the synchronization mechanism to realize accurate interpretation, and encodes the pulse position by using a pulse compression technology, changing the pulse repetition frequency, representing and sending different coding information through the change characteristics of the repetition periods of the front and rear groups of pulse groups, and effectively sending the coding information; the transmitter and the receiver adopt a synchronization mechanism, the receiving terminal realizes effective receiving of target information through echo pulse position modulation in the signal receiving process, information is extracted by using signal processing equipment, and integration based on radar communication is carried out in the aspects of hardware and waveform.

2. The pulse doppler radar sounding integrated waveform design method of claim 1, wherein: the detection radar has a fixed processing time window when processing echo data, when the communication from the receiver to the detection radar is realized, a transmitting signal of the receiver falls in the processing time window of the detection radar, and the time synchronization is carried out between the detection radar and a receiving terminal; the receiver achieves the estimation of the repetition period of the pulse group M2 and the synchronization of the start position by the pulses of the frame synchronization pulse segment.

3. The pulse doppler radar sounding integrated waveform design method of claim 3, wherein: the receiver predicts the pulse position of the corresponding pulse segment of the data and the corresponding processing time window, and transmits the echo pulse at a fixed position in the time window to realize the transmission of the reverse data.

4. The pulse doppler radar sounding integrated waveform design method of claim 1, wherein: in the radar transmission waveform, the M-th transmission sequence comprises pulse groups M1 and M2, the repetition periods of which are respectively defined as TM1 and TM2, and the N-th transmission sequence comprises pulse groups N1 and N2, the repetition periods of which are respectively defined as TN1 and TN 2.

5. The pulse doppler radar sounding integrated waveform design method of claim 5, wherein: the transmitter and the receiver use a synchronization mechanism to distinguish the detection radar signal and the communication signal by time division, frequency division, code division and space division multiplexing technology in a data response pulse section according to the detection radar transmitting waveform and the receiver transmitting waveform at the start bit, the data bit and the check bit of time t so as not to interfere with each other; the radar and communication waveforms represented by different signals are adopted in a signal domain to carry out time-sharing emission, frequency division is carried out from the angle of a transform domain, different frequency bands occupied by the detection radar and the communication signals are distinguished, and code division spreading is carried out on spread spectrum codes of the radar and the communication signals respectively.

6. The method according to claim 1, wherein the transmitter and the receiver are spatially separated from the energy domain transmitted from the antenna, so that the beams transmitted from the radar and the communication do not interfere with each other, and the two signal time domains, frequency domains, code domains or space domains of the separately generated radar signal and communication signal are superimposed and transmitted via the radar antenna.

7. The pulse doppler radar sounding integrated waveform design method of claim 1, wherein: the receiving terminal separates the received electromagnetic waves to obtain radar and communication signals, corresponding data processing is respectively carried out to obtain target parameters and communication information, the receiving terminal divides the received signals into two paths of detection radar and communication by using a power divider, signal processing is respectively carried out to extract relevant information, and the communication signals and the radar signals are combined into one without distinguishing so as to thoroughly fuse the radar and the communication.

8. The pulse doppler radar sounding integrated waveform design method of claim 1, wherein: the transmission distance of the waveform transmitted by the receiving terminal is improved by a pulse compression technology, the bit error rate is reduced by using pulse position coding, and after pulse position information is obtained by a synchronization mechanism, a specific pulse is sent at an echo position to realize a data communication function.

9. The pulse doppler radar sounding integrated waveform design method of claim 1, wherein: in the process of realizing the detection radar and the reverse asynchronous data transmission of the receiving terminal by the receiving terminal, the corresponding pulse section of single data adopts communication coding containing a start bit, a data bit and a check bit, and in a 48-bit data response pulse section: the code format of the code comprises 4 bits of start bits with the code format of 1101, 40 bits of data bits, 2 bits of check bits and 2 bits of stop bits with the code format of 01.

10. The pulse doppler radar sounding integrated waveform design method of claim 1, wherein: the radar receiver directly extracts target parameters of received signals, a receiving end despreads the received signals by adopting corresponding spreading codes, then performs two-phase coding and non-correlated pulse compression on the spread signals respectively, extracts coding information after the non-correlated pulse compression processing, and performs down-conversion, matched filtering and demodulation processing respectively to obtain recovered communication and radar communication data; the radar obtains distance and speed information of a target through down-conversion and matched filtering, a spread spectrum modulated communication signal is obtained through band-pass filtering, and the spectrum of communication signal data after being spread spectrum modulated is approximate to random noise, so that the communication signal data can be well hidden in the radar signal.

Technical Field

The invention relates to a detection and communication integrated waveform design method for a pulse Doppler radar. In particular to a pulse Doppler radar sounding integrated waveform design method.

Background

Conventionally, it is generally considered that the signal characteristics of communication and radar detection have a significant difference, and a radar apparatus is a device for detection and identification of an object, with the object detection identification being a primary purpose. The communication device is a device for realizing effective transmission of information between devices, and the detection function cannot be taken into consideration during communication. There are many differences in function and operation principle of radar and communication, but there are also common parts in hardware structure and operation frequency band. On one hand, most of signals sent by radar detection waveforms are regular structural signals, and the signals are required to have excellent autocorrelation characteristics, larger signal bandwidth and higher transmitting power, can tolerate larger Doppler frequency offset and mainly aim at estimating the distance and the speed of a moving target; on the other hand, regardless of the modulation method adopted by the communication signal, the waveform of the communication signal is random and uncertain, high spectrum utilization rate is required, and besides the frequency modulation signal, the communication signal is mostly sensitive to doppler frequency offset. Therefore, how to solve the problem of the dissimilarity of the two types of signal waveforms of communication and radar detection becomes a problem of the design of the integrated shared signal waveform.

With the development of millimeter wave radar and 5G and even future 6G wireless communication, both radar and communication need larger bandwidth and occupy the same frequency band, resulting in increasingly deficient spectrum resources, and an effective method for solving the problem is to share radar and communication waveforms, i.e., radar communication integrated waveforms. The key point for realizing radar communication integration is the design of integrated waveforms, and the selection and design of radar communication integrated waveforms are the basis for realizing a radar communication integrated system and directly influence the structures of a system transmitter and a system receiver, a signal processing mode and various system performance indexes. The existing communication and radar detection integrated signal can not completely meet the requirement, and a design method and a technical breakthrough need to be searched. The current research mainly adopts two ideas to design the waveform of the common signal: 1. the two orthogonal signal waveforms are used for modulating radar and communication signals respectively, and then the signals are transmitted in a superposition mode. The key of the idea is to search two orthogonal signal waveforms, and once the signal waveforms are not orthogonal, the functions of the radar and the communication are seriously influenced. More importantly, if the signal waveforms employed are orthogonal in frequency, the need for frequency bandwidth is increased; if the adopted signal waveforms are orthogonal in the space domain, the phase control array area and the power used by the radar are reduced, and the performance of radar detection is influenced. 2. And loading communication data in the radar signal waveform, uniformly modulating by adopting a signal waveform, and then transmitting. This method currently has single carrier and multi-carrier systems. In a single carrier system, a chirp and pseudorandom sequence are typical signal waveforms, and the single carrier system generally has the problem of low spectrum efficiency. The multi-carrier system mainly adopts OFDM signal waveforms. However, the existing OFDM signal waveform has the problem of poor performance of the integrated waveform ambiguity of the OFDM radar communication with direct information modulation due to the problem of peak-to-average power ratio, which causes the problem of system radar performance deterioration, and limits the application of the OFDM signal waveform in a high-power and long-distance radar detection system, and cannot meet the performance of requirements. The existing integrated signal waveform design adopts a sequential design method, which is usually designed from the perspective of a radar or communication single system, and then meets the requirement of another system as much as possible by adjusting signal waveform parameters. Due to the lack of integration consideration at the beginning of design, a perfect theoretical system is not provided for standardizing and guiding the design of the signal waveform, so that the designed signal waveform is difficult to give consideration to both radar and communication performances. In the radar communication integrated waveform design, the modulation of communication data can generate great influence on the radar detection performance, and the communication data efficiency and the radar detection performance cannot be considered at the same time. In addition, the electromagnetic environment of the position is complex, and the mutual interference among different electromagnetic devices is increasingly serious, so that the target detection capability of the integrated system is reduced, and the communication transmission rate and the bit error rate cannot be effectively guaranteed. The existing integrated signals all adopt fixed waveforms and cannot adapt to the complex electromagnetic environment of dynamic transformation. The fuzzy function of LFM _ MSK obtains an integrated waveform, and the Doppler fault tolerance of the integrated waveform is poorer than that of a linear frequency modulation signal under the same parameter. The sounding integrated signal waveform designed by the complicated and changeable electromagnetic environment requirement has agility, can be adaptively adjusted according to the change of the time-space characteristic of a frequency spectrum, and realizes the high-efficiency utilization of resources while realizing the acquisition of the optimal communication and sounding performance.

In recent years, a transform domain integrated signal characterization method and a time-frequency grid-based characterization method proposed in prototype filter design appear in communication signal characterization, and a new thought and method are provided for constructing a shared signal waveform integrating communication and radar detection. The basic concept of transform domain-based communication and radar detection integrated waveform design is as follows: by the integrated representation of communication and radar detection signals and based on the unified measurement criterion of the fuzzy function, a shared signal waveform which simultaneously meets the requirements of communication and radar detection is designed. According to the radar communication integrated mode, the integrated waveform design can be summarized into three types of approaches: one is based on radar waveform, and is obtained by modulating communication data on the radar waveform; secondly, based on the communication signals, the communication signals are transformed into waveforms capable of being used as radar detection; and the radar waveform and the communication waveform are independently generated and are obtained by superposition and synthesis. The existing data show that the comprehensive waveform design based on communication signals mainly focuses on transforming the OFDM signals into radar detection waveforms, although the OFDM signals have better anti-interception performance than the LFM signals and frequency hopping signals in radar application. However, the envelope fluctuation of the OFDM signal is large, the peak-to-average ratio is large, and the OFDM signal can only be used for short-distance communication or detection, such as automobile ranging and communication in intelligent transportation. If the radar communication integrated waveform is used for long-distance detection and communication, the power amplifier of the radar transmitter works in a nonlinear region, so that serious distortion of a transmitted signal is caused, and the distortion cannot be relieved through channel estimation and equalization, and is very unfavorable for demodulation. Moreover, OFDM is sensitive to doppler shift and is not suitable for communication between platforms with large relative speeds.

Through the literature search of the prior art, the following findings are found: it has been proposed to spread the radar pulse and the communication data with two orthogonal direct sequences to obtain a detection waveform and a communication modulation waveform. The two do not interfere with each other. The two waveforms are modulated to synthesize a waveform and then transmitted. The receiver adopts a de-spreading method to separate radar echo and communication signals, and then corresponding processing is carried out. This solution is relatively easy to implement, does not require a large modification of the radar, but has the following disadvantages: firstly, the transmission power is divided by the communication waveform, and the detection performance is damaged; secondly, the direct sequence is sensitive to Doppler frequency shift, and communication between platforms with high relative speed is not advisable. The OSA-based radar communication synthesis waveform generation principle classifies the above scheme as a superposition synthesis method because it can be considered to be synthesized in the frequency domain. In a communication receiver, the OFDM spectrum embedded in the wideband noise is first cut out and then demodulated. The radar receiver uses the echo of the whole signal to process and extract target information. However, the time division multiplexing system needs time synchronization, and because the radar and the communication cannot work simultaneously, the time division duplexing inevitably causes the communication system to occupy the time for the radar to detect the target, the radar has a detection blind area, the target cannot be found in time and target parameters cannot be obtained, and the working performance of the radar is affected. Since OFDM is present, this waveform is also not suitable for class C amplifiers to transmit long range communication signals, which can only be used for short range detection and communication.

In the article "radar and communication integration research" paper, log 22 of the technical development of enterprises ", volume 32, and in the article" radar-communication integration system design "of the version 2016.21 of design and research, only the definition of radar-communication integration system, the feasibility of radar communication integration and the system structure are discussed, and no corresponding waveform design method is given. These solutions, however, all suffer from such problems. Or the communication speed is low, and the requirement of high-speed communication cannot be met; or the transmitting power is segmented, and the radar detection performance is damaged; or the waveform is not suitable for the emission of a class C power amplifier of the pulse radar, and the communication demodulation performance is reduced.

Disclosure of Invention

The invention aims at the problems and the defects of the existing radar communication integrated signal design. The design method for constructing the communication-detection integrated communication signal waveform for the pulse Doppler radar, particularly the design method for the pulse Doppler radar communication integrated waveform, does not change the conventional working mode of the radar, has the advantages of covert communication and better precision of a receiving end in time reference measurement, can realize the two-way communication between the detection radar and a target while keeping the conventional detection function of the radar, improves the anti-interference capability of a system, and is oriented to the pulse Doppler radar. So as to overcome the defects of the existing integrated signal waveform. The invention discloses a pulse Doppler radar sounding integrated waveform design method, which adopts the technical scheme that: a pulse Doppler radar sounding integrated waveform design method is characterized by comprising the following steps: the detection radar and the receiving terminal carry out data transmission communication information of both parties in a two-way communication modulation mode, the communication information is modulated by frequency points of a carrier, and information modulation and time synchronization are realized by utilizing the intentional modulation of a pulse Doppler radar repetition period and the change of repetition frequency among pulse groups; in time t, radar emission waveforms are transmitted for the Mth time to form a pulse group M2, and transmitted for the Nth time to form a pulse group N1 and a pulse group N2, a communication receiver intercepts an OFDM frequency spectrum embedded in broadband noise, then demodulation processing is carried out, echo of the whole signal is used for processing, target information is extracted, an electromagnetic wave is emitted by an antenna through the transmitter, and a receiving end receives the signal transmitted through a channel; the pulse group N1 and the pulse group M2 carry out a synchronization mechanism in a frame synchronization pulse section, a receiver identifies and preprocesses an address after receiving data, increases the number of sub-pulses of a group of sequences, realizes data demodulation by extracting parameters, modulates communication data into an integrated signal, transmits a waveform by a receiver, falls a transmitted signal in a processing time window of a detection radar in a data response pulse section, carries out estimation of a pulse group M2 repetition period and synchronization of an initial position on the pulse of the frame synchronization pulse section to realize reverse asynchronous data transmission of the detection radar and a receiving terminal, then predicts the pulse position of the corresponding pulse section of the data and the corresponding processing time window, transmits a specific pulse at a fixed position in the time window, analyzes symbol change of a transmitting terminal after pulse position information is obtained through the synchronization mechanism to realize accurate interpretation, and encodes the pulse position by using a pulse compression technology, changing the pulse repetition frequency, representing and sending different coding information through the change characteristics of the repetition periods of the front and rear groups of pulse groups, and effectively sending the coding information; the transmitter and the receiver adopt a synchronization mechanism, the receiving terminal realizes effective receiving of target information through echo pulse position modulation in the signal receiving process, information is extracted by using signal processing equipment, and integration based on radar communication is carried out in the aspects of hardware and waveform. The invention aims to provide an effective pulse waveform design method for the design of a detection and communication integrated radar, so that the normal detection function of the radar is ensured, and the two-way communication function of the detection radar and a target is realized.

Compared with the prior art, the invention has the following advantages:

the method has the characteristic of covert communication. In order to keep the capability of the pulse Doppler radar in the aspects of pulse compression, coherent accumulation and the like, the invention keeps the modulation characteristics in radar pulses unchanged, the width of the radar pulses unchanged and the number of the coherent accumulation pulses of the radar unchanged. In the design of radar emission waveform, the characteristics that the conventional pulse Doppler radar needs to change repetition frequency to solve velocity ambiguity and change repetition period to solve velocity are fully utilized, and different coding information is sent by representing the change characteristics of the repetition period of the front pulse group and the rear pulse group. The intentional modulation of the repetition frequency in the waveform design of the pulse Doppler radar is utilized to realize the effective transmission of the coded information, and the hidden communication function can be realized while the normal detection function of the radar is realized. The receiving end utilizes a plurality of pulse periods to realize time synchronization and code element position locking, data return is realized in an effective distance gate, the anti-interference capability of the system is improved, the error rate of the integrated waveform is obtained according to a time frequency result and is in an optimal solution, and energy leakage is solved.

Has better precision. The invention adopts a detection radar and a receiving terminal to carry out data transmission communication information of both parties in a two-way communication modulation mode, utilizes the intentional modulation of the pulse Doppler radar repetition period, realizes information modulation and time synchronization through the change of the repetition frequency between pulse groups, and ensures the synthesis bandwidth of an integrated signal by increasing the number of sub-pulses of a group of sequences, namely increasing the possibility of different carrier frequencies. The receiver has a better accuracy in time reference measurement, typically up to 10ns accuracy when making pulse repetition period (inverse of the repetition frequency) measurements. Therefore, when the wave form of the transmitting end is designed, the mode of operation of the conventional radar is not changed by superposing 0.1% -1% of intentional modulation on the repetition frequency.

The invention adopts radar emission waveform in time t to form a pulse group M2 by Mth emission and form a pulse group N1 and a pulse group N2 by Nth emission, a transmitter emits electromagnetic waves through an antenna, and a receiving end receives signals transmitted through a channel; the pulse group N1 and the pulse group M2 carry out a synchronization mechanism in a frame synchronization pulse section, a receiver transmits a waveform, a transmission signal falls in a processing time window of a detection radar in a data response pulse section, the pulse of the frame synchronization pulse section carries out estimation of a pulse group M2 repetition period and synchronization of an initial position, reverse asynchronous data transmission of the detection radar and a receiving terminal is realized, the waveform carries communication data, and the communication receiver demodulates the waveform signal and extracts communication information; and processing the waveform echo at a radar receiver to extract target information. The method realizes communication and radar detection, has no detection blind area, successfully inhibits overhigh time delay sidelobe based on time delay sidelobe inhibition of windowed deconvolution, and improves the system utilization rate and the frequency spectrum utilization rate.

In the radar transmitting waveform, the coding information is effectively transmitted by changing the pulse repetition frequency, and the target information is effectively received by modulating the echo pulse position in the signal receiving process; the transmitting end and the receiving end realize pulse synchronization through pulse parameter change, and the receiving end can better analyze code element change of the transmitting end to realize accurate interpretation. Meanwhile, parameters such as pulse width and pulse compression ratio which have great influence on the performance of the conventional radar are not changed, and the detection performance index of the radar is not changed. After pulse position information is obtained through a synchronization mechanism, code element change of a transmitting end is analyzed to realize accurate interpretation, pulse positions are coded by using a pulse compression technology, pulse repetition frequency is changed, different coding information is sent according to the change characteristics of the repetition period of the front group of pulse groups and the rear group of pulse groups, and the coding information is effectively sent; the radar detection waveform and the communication modulation waveform are fused together, so that the communication quality is improved, and networking and automation of radar and communication are facilitated. Simulation experiments prove that the integrated signal has better effect in radar imaging and communication.

Drawings

The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 illustrates the operation of the radar detection communication of the pulse Doppler detection integrated radar waveform of the present invention;

fig. 2 is a schematic diagram of transmit and receiver waveforms of the transmitter of fig. 1.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention shall be described in detail with reference to specific embodiments. It should be noted that the following examples will aid those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Detailed Description

Fig. 2. According to the invention, the detection radar and the receiving terminal carry out data transmission communication information of both parties in a bidirectional communication modulation mode, the communication information is modulated by the frequency point and the repetition frequency period of a carrier, the intentional modulation of the repetition period of the pulse Doppler radar is utilized, and the information modulation and the time synchronization are realized by the change of the repetition frequency between pulse groups; in time t, radar emission waveforms are transmitted for the Mth time to form a pulse group M2, and transmitted for the Nth time to form a pulse group N1 and a pulse group N2, a communication receiver intercepts an OFDM frequency spectrum embedded in broadband noise, then demodulation processing is carried out, echo of the whole signal is used for processing, target information is extracted, an electromagnetic wave is emitted by an antenna through the transmitter, and a receiving end receives the signal transmitted through a channel; the pulse group N1 and the pulse group M2 carry out a synchronization mechanism in a frame synchronization pulse section, a receiver identifies and preprocesses an address after receiving data, increases the number of sub-pulses of a group of sequences, realizes data demodulation by extracting parameters, modulates communication data into an integrated signal, transmits a waveform by a receiver, falls a transmitted signal in a processing time window of a detection radar in a data response pulse section, carries out estimation of a pulse group M2 repetition period and synchronization of an initial position on the pulse of the frame synchronization pulse section to realize reverse asynchronous data transmission of the detection radar and a receiving terminal, then predicts the pulse position of the corresponding pulse section of the data and the corresponding processing time window, transmits a specific pulse at a fixed position in the time window, analyzes symbol change of a transmitting terminal after pulse position information is obtained through the synchronization mechanism to realize accurate interpretation, and encodes the pulse position by using a pulse compression technology, changing the pulse repetition frequency, representing and sending different coding information through the change characteristics of the repetition periods of the front and rear groups of pulse groups, and effectively sending the coding information; the transmitter and the receiver adopt a synchronization mechanism, the receiving terminal realizes effective receiving of target information through echo pulse position modulation in the signal receiving process, information is extracted by using signal processing equipment, and integration based on radar communication is carried out in the aspects of hardware and waveform. The invention aims to provide an effective pulse waveform design method for the design of a detection and communication integrated radar, so that the normal detection function of the radar is ensured, and the two-way communication function of the detection radar and a target is realized.

As shown in fig. 2, the transmitter and receiver synchronization mechanism is designed as follows: because the detection radar has a fixed processing time window when processing echo data, when the communication from the receiver to the detection radar is realized, the transmission signal of the receiver is required to fall in the processing time window of the detection radar, and therefore, the time synchronization is required between the detection radar and the receiving terminal. The receiver achieves the estimation of the repetition period of the pulse group M2 and the synchronization of the start position by the pulses of the frame synchronization pulse segment. And then, the receiver predicts the pulse position of the corresponding pulse segment of the data and a corresponding processing time window, and transmits the echo pulse at a fixed position in the time window to realize the transmission of reverse data. In the radar transmission waveform, the M-th transmission sequence comprises pulse groups M1 and M2, and the repetition periods of the pulse groups are respectively defined as TM1 and TM 2. The Nth emission sequence comprises pulse groups N1 and N2, and the repetition periods of the pulse groups are TN1 and TN2 respectively.

By extending the relevant characteristics of pulse groups M1 and M2, the required symbol space is defined by the rate of change, the step of change, etc. Specifically, the transmitter and the receiver use a synchronization mechanism to distinguish the detection radar signal and the communication signal by using time division, frequency division, code division and space division multiplexing technologies at the start bit, the data bit and the check bit of time t according to the detection radar transmission waveform and the receiver transmission waveform in a data response pulse section so as not to interfere with each other; radar represented by different signals and communication waveforms are adopted in a signal domain to carry out time-sharing transmission; and frequency division is carried out from the angle of a transform domain, different frequency bands occupied by the detection radar and the communication signals are distinguished, and code division spreading is carried out on the spreading codes of the radar and the communication signals respectively.

The transmitter and the receiver are space-divided from the angle of an energy domain transmitted by an antenna, beams transmitted by radar and communication are enabled not to interfere with each other, and then two signal time domains, frequency domains, code domains or space domains of the radar signal and the communication signal which are respectively and independently generated are superposed and transmitted by the radar antenna.

The receiving terminal separates the received electromagnetic waves to obtain radar and communication signals, corresponding data processing is respectively carried out to obtain target parameters and communication information, the receiving terminal divides the received signals into two paths of detection radar and communication by using a power divider, signal processing is respectively carried out to extract relevant information, and the communication signals and the radar signals are combined into one without distinguishing so as to thoroughly fuse the radar and the communication.

Designing a transmitting waveform of a receiving terminal: because coherent accumulation can not be realized by the detection radar and the receiving terminal, the transmission distance is improved by a pulse compression technology, and the error rate is reduced by pulse position coding. Specifically, as shown in fig. 2, "receiver transmit waveform", after pulse position information is obtained by a synchronization mechanism, a data communication function is realized by transmitting a specific pulse at an echo position. Typically, the transmit inverse chirp signal represents a 1 and the no-transmit signal represents a 0.

Receiving terminal communication coding design: in the asynchronous data transmission between the receiving terminal and the detection radar, the corresponding pulse section of single data adopts communication coding containing a start bit, a data bit and a check bit, and in the 48-bit data response pulse section: the code format of the code comprises 4 bits of start bits with the code format of 1101, 40 bits of data bits, 2 bits of check bits and 2 bits of stop bits with the code format of 01.

The radar receiver directly extracts target parameters of received signals, a receiving end despreads the received signals by adopting corresponding spreading codes, then performs two-phase coding and non-correlated pulse compression on the spread signals respectively, extracts coding information after the non-correlated pulse compression processing, and performs down-conversion, matched filtering and demodulation processing respectively to obtain recovered communication and radar communication data; the radar obtains distance and speed information of a target through down-conversion and matched filtering, a spread spectrum modulated communication signal is obtained through band-pass filtering, and the spectrum of communication signal data after being spread spectrum modulated is approximate to random noise, so that the communication signal data can be well hidden in the radar signal.

The communication receiver analyzes the pulse code group through the beacon and modulates the pulse with the trigger pulse into a 'control code'. The correct pulse interval for the inquiry "control code" is checked. If the interrogation code is correct, the trigger pulse will trigger the beacon transmitter with a fixed delay and pass the control code to the command decoder.

The present invention has been described in detail with reference to the accompanying drawings, but it should be noted that the proportional relationship between the front and back groups of repetition periods and the related characteristics described herein may be changed for different applications; the receiver described herein transmits pulse code patterns that may vary from application to application; the data described herein may have different definitions for different applications, depending on the respective burst lengths; the length and form of the start bit code and the length and form of the stop bit code described herein may vary for different applications. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention. The present invention is not described in detail, but is within the common general knowledge of those skilled in the art.