CN116299430A - Radar communication integrated signal generating device based on pulse frequency agility - Google Patents
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Abstract
The invention relates to a radar communication integrated signal generating device based on pulse frequency agility, and belongs to the technical field of radar communication integration. The device comprises a spread spectrum modulation unit, a pulse modulation unit, a nonlinear unit and a power amplification unit; the spread spectrum modulation unit receives user data, loads the data to a pseudo-random sequence through data grouping, selection mapping and phase shift mapping to realize spread spectrum modulation, and outputs the data to the pulse modulation unit; the pulse modulation unit completes pulse amplitude modulation and outputs the pulse amplitude modulation to the nonlinear unit after integration; the nonlinear unit generates radar communication integrated signals with a carrier frequency and a phase being pseudo-randomly variable based on the third power nonlinear frequency modulation signals and outputs the radar communication integrated signals to the power amplification unit; and the power amplification unit performs power amplification on the received signal and outputs the power amplified signal to the antenna. The invention improves the anti-interference capability, the information transmission capability and the power utilization rate of the radar communication integrated modulation signal.
Description
Technical Field
The invention relates to a radar communication integrated signal generating device based on pulse frequency agility, and belongs to the technical field of radar communication integration.
Background
Radar detection and wireless communication are two of the most common and most important applications in modern radio technologies, and are independently designed and developed according to different functions and frequency bands, wherein the radar is mainly used for detecting and identifying targets, and the purpose of communication is to realize information transmission between devices. But as the number of wireless devices increases exponentially and higher bandwidth demands are demanded for high speed data transmission, overcrowding of the electromagnetic spectrum results; in military applications, the threat of weapon platforms and complex electromagnetic environments are increasingly facing, the countermeasure between single electronic equipment cannot meet the requirement of future battlefield battle form diversification, and radar communication integration is an effective approach for solving the problems.
Suppression interference, retransmission interference, spoofing interference are typical interference patterns for radar electronics. In the field of radar communication integration, it is very important to improve the validity of a radar communication integration system and the anti-electronic interference capability of the system, and important indexes such as flexibility, reliability and the like of a detected target are related. With the development of radar electronic countermeasure technology, especially the rapid development of active interference technology based on digital radio frequency memory, the radar communication integrated signal can have adaptability in complex electromagnetic environment, which brings serious challenges to the design of the radar communication integrated signal. In the field of radar communication integration, the prior art has little research on how to improve the anti-interference capability of radar communication integrated signals.
Therefore, how to improve the anti-interference capability of the radar communication integrated signal is a difficult problem to be solved by the existing radar communication integrated signal design.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provide the pulse frequency agility radar communication integrated signal generating device capable of improving the anti-interference capability of the radar communication integrated signal.
The invention relates to a radar communication integrated signal generating device based on pulse frequency agility, which comprises a spread spectrum modulation unit, a pulse modulation unit, a nonlinear unit and a power amplification unit;
the spread spectrum modulation unit receives user data, loads the data to a pseudo-random sequence through data grouping, selection mapping and phase shift mapping to realize spread spectrum modulation, and outputs the data to the pulse modulation unit;
the pulse modulation unit completes pulse amplitude modulation and outputs the pulse amplitude modulation to the nonlinear unit after integration;
the nonlinear unit generates radar communication integrated signals with a carrier frequency and a phase being pseudo-randomly variable based on the third power nonlinear frequency modulation signals and outputs the radar communication integrated signals to the power amplification unit;
and the power amplification unit performs power amplification on the received signal and outputs the power amplified signal to the antenna.
Further, in the technical scheme disclosed by the invention, the spread spectrum modulation unit comprises a data grouping module, a pseudo random sequence generating module, a selection mapping module and a phase shift mapping module;
the data grouping module groups the received user data, wherein the grouping comprises a p-bit selection mapping group and a q-bit shift mapping group, the p-bit selection mapping group is output to the selection mapping module, and the q-bit shift mapping group is output to the phase shift mapping module;
the pseudo-random sequence generating module is used for generating N pseudo-random sequences which are orthogonal or quasi-orthogonal in pairs and have M digits, and outputting the N pseudo-random sequences to the selection mapping module;
the selection mapping module maps each data combination of the p-bit selection mapping group into an ith pseudo-random sequence selected from the N pseudo-random sequences according to a one-to-one mapping relation, and outputs the ith pseudo-random sequence to the phase shift mapping module, wherein each data combination of the p-bit selection mapping group can be mapped with only one pseudo-random sequence, and the pseudo-random sequences mapped by any two data combinations are different;
the phase shift mapping module maps each data combination of the q-phase shift mapping group into a cyclic shift state of the ith pseudo-random sequence according to a one-to-one mapping relation and outputs the cyclic shift state to the pulse modulation unit; each data combination of the q-phase shift mapping group can only be mapped with one cyclic shift state of the ith pseudorandom sequence, and the cyclic shift states of the pseudorandom sequences mapped by any two data combinations are different.
Further, in the technical scheme disclosed by the invention, the pulse modulation unit comprises a pulse waveform generation module, a pulse amplitude modulation module and an integration module;
the pulse waveform generation module is used for generating a pulse waveform gamma (t) and outputting the pulse waveform gamma (t) to the pulse amplitude modulation module;
the pulse amplitude modulation module is connected with the phase shift mapping module, and is used for loading each bit of data in the ith pseudorandom sequence cyclic shift state onto the pulse waveform gamma (t) in sequence and outputting the data to the integration module;
the integration module integrates the received signals and outputs the integrated signals to the nonlinear unit.
Further, in the technical scheme disclosed by the invention, the nonlinear unit comprises a carrier frequency control module, a phase control module and a nonlinear modulation module;
the carrier frequency control module is used for generating a pseudo-random carrier frequency signal f c And output to the nonlinear modulation module;
the phase control module is used for generating pseudo-random phase signals
And output to the nonlinear modulation module;
the nonlinear modulation module is connected with the integration module and takes the received integrated signal as an additional phase of a third power nonlinear frequency modulation signal; the nonlinear modulation module is used for modulating the carrier frequency signal according to the pseudo-random carrier frequency signal f c And the pseudo-random phase signal
The method comprises the steps of generating radar communication integrated signals and outputting the radar communication integrated signals to the power amplification unit, wherein the radar communication integrated signals are as follows:
wherein f c Is the carrier frequency of the radar communication integrated signal, B is the signal bandwidth factor, T is the signal time factor,
the j-th bit data of the kth cyclic shift state of the ith pseudo-random sequence participating in modulation, k is a positive integer, k=0, 1,2, … M-1, j is a positive integer, j=1, 2, … M.
Further, in the technical scheme disclosed in the invention, the pseudo-random phase signal generated by the phase control module
Is in the range of [ -pi, pi]And is statistically independent between each bit of data of the cyclic shift state of the ith pseudorandom sequence.
Further, in the technical scheme disclosed in the invention, the carrier frequency control module generates a pseudo-random carrier frequency signal f c Is a slave hopping sequence [ f 1 ,f 2 ,…,f M ]And is statistically independent between each bit of data of the cyclic shift state of the ith pseudorandom sequence.
Further, in the technical scheme disclosed by the invention, the cyclic shift is cyclic left shift or cyclic right shift, and 1bit of data is cyclically shifted each time.
Further, in the technical solution disclosed in the present invention, the number p of bits of the selected mapping group and the number N of pseudo random sequences satisfy the relation:
sign->
Representing a rounding down.
Further, in the technical scheme disclosed in the invention, the number q of bits of the phase shift mapping group and the number M of bits of the pseudo random sequence satisfy the relation:
sign->
Representing a rounding down.
Preferably, in the technical scheme disclosed by the invention, the pulse waveform gamma (t) is a 0-order long spherical wave function.
Compared with the prior art, the invention has the following beneficial effects:
(1) Improving the capacity of resisting the system interference
In the technical scheme disclosed by the invention, the carrier frequency control module of the nonlinear unit is used for controlling the frequency hopping sequence [ f ] 1 ,f 2 ,…,f M ]Pseudo-randomly generated carrier frequency signal f c And the data of each bit of the cyclic shift state of the ith pseudo-random sequence are statistically independent, so that the pulse frequency agility of the radar communication integrated signal is realized, the suppression type interference signal is difficult to track the frequency change of the radar communication integrated signal on the frequency domain, and effective interference cannot be implemented. In the prior art, the carrier frequency of the radar communication integrated signal is usually fixed and is difficult to resist the jamming. Thus, compared with the prior art, the inventionThe capacity of radar communication integrated signal compression type interference resistance is obviously improved.
(2) Improving the capability of resisting deception jamming
In the technical scheme disclosed by the invention, the spread spectrum unit loads the user data to be transmitted onto the pseudo-random sequence through the selection mapping module and the phase shift mapping module, so that the spectrum spreading is realized, the power spectrum density of the radar communication integrated modulation signal is reduced, the concealment is improved, the parameter of the radar communication integrated signal is difficult to master by an interference party, and the deceptive interference is difficult to implement by the interference party.
(3) Improving the capability of resisting forwarding interference
In the technical scheme disclosed by the invention, the phase control module of the nonlinear unit adopts a random initial phase mode, so that radar communication integrated signals are prevented from being accumulated in a coherent manner with forwarding interference in a time domain; further, because the pseudo-random sequences mapped by different data packets are different, the receiving system can convert the interference signals carrying different pseudo-random sequences into low-power spectrum noise signals by utilizing the orthogonality or quasi-orthogonality of the pseudo-random sequences, thereby effectively inhibiting the forward interference and improving the anti-interference capability.
(4) Signal-to-interference ratio of radar communication integrated signal is improved
In the prior art, a linear frequency modulation signal is generally adopted to design a radar communication integrated signal, the signal has larger side lobes, and when the side lobes are restrained by a filter, the radar signal can generate serious waveform distortion, so that the anti-interference capability of the radar signal in the channel transmission process is reduced. In the technical scheme disclosed by the invention, the nonlinear frequency domain characteristic is constructed by adopting the third power so as to achieve the purpose of reducing the amplitude of a side lobe of a radar signal, reduce the signal distortion generated when the side lobe is restrained, and improve the signal-to-interference ratio of the radar signal, thereby enhancing the reliability of radar communication integrated signal transmission.
(5) The power utilization rate of the system is improved
In the technical scheme disclosed by the invention, the pulse modulation unit finishes the pulse waveform of data loading, and outputs the pulse waveform to the nonlinear unit in an integral form to serve as an additional phase of a third power nonlinear frequency modulation signal so as to realize radar communication integrated waveform design, so that the integrated modulation signal has constant envelope characteristics. Therefore, compared with the prior art, the power utilization rate of the radar system can be effectively improved, and the acting distance for target detection is enhanced.
Drawings
Fig. 1 is a schematic diagram of the pulse frequency agility based radar communication integrated signal generating device of the present invention.
Detailed Description
The present invention is described in further detail below with reference to examples and drawings to enable those skilled in the art to practice the same and to refer to the description.
In the prior art, designing radar communication integrated waveforms based on OFDM is a research hotspot in the existing radar communication integrated field. However, the inherent peak average bit property of OFDM greatly reduces the power utilization rate of the system, reduces the anti-interference capability of radar communication integrated signals, and reduces the distance for target detection, thereby seriously affecting the working performance of the radar system.
In the prior art, in order to overcome the defects of OFDM, a linear frequency modulation signal is adopted to design a radar communication integrated signal, so that the radar communication integrated signal has constant envelope characteristics, the power efficiency of a system is guaranteed, and the radar communication integrated signal has a wider spectrum bandwidth, so that the resolution can be improved when the radar communication integrated signal is used for detecting a target. However, the linear frequency modulation signal has larger frequency spectrum sidelobes, and when the sidelobes are suppressed by filtering, the modulation signal can generate serious waveform distortion, so that the SNR (signal to noise ratio) of the signal is reduced, the capability of resisting electronic interference is reduced, and the application environment is limited. Along with the development of radar electronic countermeasure technology, especially the rapid development of active interference technology based on digital radio frequency memory, the adaptability of radar communication integrated signals in complex electromagnetic environment is challenged, and the anti-interference capability of the radar communication integrated signals must be improved.
In order to solve the problem and improve the anti-interference capability of radar communication integrated signals, the embodiment of the invention discloses a radar communication integrated signal generating device based on pulse frequency agility. As shown in fig. 1, the device comprises a spread spectrum modulation unit, a pulse modulation unit, a nonlinear unit and a power amplification unit; the spread spectrum modulation unit receives user data, loads the data to a pseudo-random sequence through data grouping, selection mapping and phase shift mapping to realize spread spectrum modulation, and outputs the data to the pulse modulation unit; the pulse modulation unit completes pulse amplitude modulation and outputs the pulse amplitude modulation to the nonlinear unit after integration; the nonlinear unit generates radar communication integrated signals with a carrier frequency and a phase being pseudo-randomly variable based on the third power nonlinear frequency modulation signals and outputs the radar communication integrated signals to the power amplification unit; and the power amplification unit performs power amplification on the received signal and outputs the power amplified signal to the antenna.
Further, as shown in fig. 1, in the technical scheme disclosed in the embodiment of the present invention, the spread spectrum modulation unit includes a data grouping module, a pseudo random sequence generating module, a selection mapping module and a phase shift mapping module;
the data grouping module groups the received user data, wherein the grouping comprises a p-bit selection mapping group and a q-bit shift mapping group, the p-bit selection mapping group is output to the selection mapping module, and the q-bit shift mapping group is output to the phase shift mapping module;
the pseudo-random sequence generating module is used for generating N pseudo-random sequences which are orthogonal or quasi-orthogonal in pairs and have M digits, and outputting the N pseudo-random sequences to the selection mapping module;
the selection mapping module maps each data combination of the p-bit selection mapping group into an ith pseudo-random sequence selected from the N pseudo-random sequences according to a one-to-one mapping relation, and outputs the ith pseudo-random sequence to the phase shift mapping module, wherein each data combination of the p-bit selection mapping group can be mapped with only one pseudo-random sequence, and the pseudo-random sequences mapped by any two data combinations are different;
the phase shift mapping module maps each data combination of the q-phase shift mapping group into a cyclic shift state of the ith pseudo-random sequence according to a one-to-one mapping relation and outputs the cyclic shift state to the pulse modulation unit; each data combination of the q-phase shift mapping group can only be mapped with one cyclic shift state of the ith pseudorandom sequence, and the cyclic shift states of the pseudorandom sequences mapped by any two data combinations are different.
In the technical scheme disclosed by the embodiment of the invention, the data to be transmitted by the user are grouped, and the data to be transmitted are mapped into the pseudo-random sequence c by selecting the modes of mapping and phase shift mapping i A certain cyclic shift state of (t), said pseudo-random sequence c i The number of bits M of (t) being greater than the number of bits of the data packet, i.e. the pseudo-random sequence c i The chip duration in (t) is smaller than the data duration in the data packet, after mapping is completed according to the transformation relation between duration and frequency spectrum, the frequency spectrum widening is realized, and the frequency spectrum spreading effect is achieved, so that the power spectrum density of the signal is reduced, the hiding capacity of the signal is improved, and the reconnaissance equipment is difficult to obtain the waveform parameters of the radar communication integrated signal. The deceptive jamming is to intercept the interfered signal by interception equipment, analyze the signal characteristics of the interfered signal to obtain signal parameters, and release deceptive jamming signals with similar parameters by the jammer on the basis of the signal parameters so as to implement jamming. Therefore, according to the technical scheme disclosed by the embodiment of the invention, the user data is converted into the pseudo-random sequence in a data grouping and mapping mode, so that the hiding capability of the radar communication integrated signal is improved, the parameter of the radar communication integrated signal is difficult to master by an interfering party, and effective interference cannot be implemented.
Further, in the technical scheme disclosed in the embodiment of the invention, the pulse modulation unit comprises a pulse waveform generation module, a pulse amplitude modulation module and an integration module;
the pulse waveform generation module is used for generating a pulse waveform gamma (t) and outputting the pulse waveform gamma (t) to the pulse amplitude modulation module;
the pulse amplitude modulation module is connected with the phase shift mapping module, and is used for loading each bit of data in the ith pseudorandom sequence cyclic shift state onto the pulse waveform gamma (t) in sequence and outputting the data to the integration module;
the integration module integrates the received signals and outputs the integrated signals to the nonlinear unit.
Further, in the technical solution disclosed in the embodiment of the present invention, in the spread spectrum modulation unit, each data combination of the p-bit selection mapping group is mapped by the selection mapping module to select an ith pseudorandom sequence from N pseudorandom sequences to participate in modulation, that is, the pseudorandom sequences mapped by different data combinations of the selection mapping group are different, so that the pseudorandom sequences adopted by different data packets are different. Preferably, the N pseudo-random sequences are mutually orthogonal or quasi-orthogonal. The radar communication integrated receiving system can utilize the orthogonal or quasi-orthogonal relation between different pseudo-random sequences to receive useful signals according to the correlation matching; for the forwarded interference signal, especially the forwarded interference signal crossing the data packet, since the pseudo random sequences adopted by different data packets are different from each other, and the pseudo random sequences carried by the forwarded interference signal and the pseudo random sequences carried by the interfered signal satisfy the orthogonal or quasi orthogonal relationship, the forwarded interference signal after the relevant receiving process has a lower correlation value, and the forwarded interference signal can be converted into a low-power spectrum noise signal. If effective forwarding interference is to be implemented, the whole process of forwarding interference must be completed within one data packet time; the time for a data packet is extremely short, which forces the repeater-type interference platform to be very close to the interfered platform, which is difficult to achieve in a practical battlefield environment. Therefore, the technical scheme disclosed by the embodiment of the invention can effectively inhibit the forwarding interference.
Further, in the technical scheme disclosed in the embodiment of the invention, the nonlinear unit comprises a carrier frequency control module, a phase control module and a nonlinear modulation module;
the carrier frequency control module is used for generating a pseudo-random carrier frequency signal f c And output to the nonlinear modulation module;
for the phase control moduleGenerating pseudo-random phase signals
And output to the nonlinear modulation module;
the nonlinear modulation module is connected with the integration module and takes the received integrated signal as an additional phase of a third power nonlinear frequency modulation signal; the nonlinear modulation module is used for modulating the carrier frequency signal according to the pseudo-random carrier frequency signal f c And the pseudo-random phase signal
The method comprises the steps of generating radar communication integrated signals and outputting the radar communication integrated signals to the power amplification unit, wherein the radar communication integrated signals are as follows:
wherein f c Is the carrier frequency of the radar communication integrated signal, B is the signal bandwidth factor, T is the signal time factor,
the j-th bit data of the kth cyclic shift state of the ith pseudo-random sequence participating in modulation, k is a positive integer, k=0, 1,2, … M-1, j is a positive integer, j=1, 2, … M, i is a positive integer, i=1, 2, … N.
In order to further prevent the radar communication integrated signal from being accumulated with the forwarded interference signal in the time domain and the frequency domain, in the technical scheme disclosed by the embodiment of the invention, the pseudo-random phase signal generated by the phase control module
Is in the range of [ -pi, pi]And is statistically independent between each bit of data of the ith pseudorandom sequence cyclic shift state, thereby further increasing the phase diversity between the integrated signal and the repeater interference. Method for combining orthogonal pseudo-random sequence and pseudo-random phaseThe formula avoids radar communication integrated signals and forwarding type interference signals from being accumulated in a coherent mode on a time domain and a frequency domain, and therefore anti-interference capability is further improved. When the receiving end processes signals, the correction of the pseudo-random phase can be realized through phase compensation. The phase compensation is a common technical means for those skilled in the art, and will not be described in detail herein.
Further, in the technical scheme disclosed by the embodiment of the invention, the nonlinear unit constructs a nonlinear frequency modulation signal based on the third power, and on the basis, the integral signal of the pulse modulation module is used as an additional phase of the third power nonlinear frequency modulation signal to form a radar communication integrated signal. The third power frequency domain characteristic enables the radar modulation signal to present nonlinear characteristic so as to achieve the purpose of reducing the side lobe amplitude of the radar modulation signal, and reduces signal distortion generated when the radar signal is radiated through antenna filtering, so that the SNR (signal to noise ratio) of the radar signal is improved, the radar modulation signal has stronger electromagnetic interference resistance in the channel transmission process, and the applicable application environment is expanded.
Therefore, the technical scheme disclosed by the embodiment of the invention adopts the non-linear frequency modulation signal to design the radar signal, so that the transmission reliability of the radar signal can be improved, and on the basis, the radar signal and the communication modulation signal are integrally designed to achieve better radar detection performance and data transmission performance.
Further, in the technical solution disclosed in the embodiment of the present invention, the carrier frequency control module generates a pseudo-random carrier frequency signal f c Is a slave hopping sequence [ f 1 ,f 2 ,…,f M ]And statistically independent among each bit of data in the ith pseudorandom sequence cyclic shift state, so that the carrier frequency of the transmitted radar communication integrated signal is in pseudorandom jump on a preset frequency point, and the pulse frequency agility of the radar communication integrated signal is realized. To implement effective squelch interference, the jammer must enable the squelch interference signal to track the frequency variation of the radar communication integrated signal in the frequency domain. However, pseudo-random due to the carrier frequency control simulationCarrier frequency variations are key controlled and therefore interference parties have difficulty in implementing suppressed interference. With respect to pseudo-random carrier frequency signal f c How to slave the hopping sequence [ f 1 ,f 2 ,…,f M ]The pseudo-random selection of the codes can be realized by adopting a frequency hopping technology, and is a conventional technical means for those skilled in the art, and is not repeated here.
According to the analysis, the technical scheme disclosed by the embodiment of the invention can effectively resist deception type interference, forwarding type interference and suppression type interference, and effectively improve the anti-interference capability of radar communication integrated signals.
In the prior art, the anti-interference capability of a system is improved by a spread spectrum mode, and the information transmission capability of the system is generally sacrificed. Furthermore, in the existing radar communication integrated field, when information transmission is performed, the information is loaded only through the amplitude, frequency and phase parameters of a transmission waveform, and the constraint of an information loading mode is high, so that the information transmission efficiency of the system is low.
In order to further improve the information transmission efficiency of the system, the inventor discards the traditional mode of loading data by parameters and expands the way of transmitting waveform loading data. The information is loaded simultaneously by adopting three modes of pseudo-random sequence selection mapping, pseudo-random sequence phase shift mapping and pulse amplitude modulation, so that the information transmission efficiency of the system is effectively improved.
And the p-bit selection mapping group is mapped to select an ith pseudo-random sequence from N pseudo-random sequences to participate in modulation according to a one-to-one mapping relation, each data combination of the p-bit selection mapping group can only be mapped with one pseudo-random sequence, and the pseudo-random sequences mapped by any two data combinations are different.
And the phase shift mapping of the pseudo-random sequence, namely the phase shift mapping module of the spread spectrum modulation unit, maps the q-phase shift mapping groups generated by the data grouping module into the cyclic shift states of the ith pseudo-random sequence according to a one-to-one mapping relation, wherein each data combination of the q-phase shift mapping groups can only be mapped with one cyclic shift state of the ith pseudo-random sequence, and the cyclic shift states mapped by any two data combinations are different.
And pulse amplitude modulation, namely a pulse amplitude modulation module of the pulse modulation unit sequentially loads each bit of data in the ith pseudo-random sequence cyclic shift state onto a pulse waveform gamma (t) generated by the pulse waveform generation module.
Therefore, parameters such as pseudo-random sequence selection, pseudo-random sequence cyclic shift state, pulse amplitude and the like can be fully utilized to carry data at the same time, and the information transmission efficiency of the system is improved. Furthermore, in order to reduce the peak-to-average ratio of the modulation signal, a time domain superposition mode of a multi-carrier modulation technology is abandoned, the nonlinear unit takes an integral form of a signal formed by pseudo-random sequence selection mapping, pseudo-random sequence phase shift mapping and pulse amplitude modulation as an additional phase of a nonlinear frequency modulation signal so as to realize radar communication integrated signal design, the nonlinear radar signal has constant envelope characteristics, and when the nonlinear radar signal is transmitted to a channel, the power utilization rate of a radar system is high, the detection target distance is long, and the problem of radar performance reduction caused by peak-to-peak ratio in the prior art is solved.
When the pulse amplitude is used for loading data, the main lobe energy aggregation of the modulated signal is greatly influenced by the pulse form; the better the energy concentration of the main lobe, the better the detection target performance, and conversely, the worse. In the technical scheme disclosed by the embodiment of the invention, the pulse waveform generated by the pulse waveform generating module is a long spherical wave function gamma (t); preferably, the γ (t) is a 0-order long spherical wave function, and the time bandwidth product factor is c=4pi, and at this time, the main lobe energy aggregation of the modulation signal can reach more than 99%, so that the modulation signal has stronger anti-interference capability when being used for channel transmission. Moreover, the gamma (t) also has a large time bandwidth characteristic, and the high energy aggregation is beneficial to improving the resolution of a detection target when the gamma (t) is used in the radar field.
Further, in the technical solution disclosed in the embodiment of the present invention, the selective mapping module of the spread spectrum modulation unit passes throughThe 1 st information loading is completed by the pseudo-random sequence selection mapping. The pseudo-random sequence selection mapping means that a certain pseudo-random sequence is selected from N pseudo-random sequences to participate in modulation. It is unknown which pseudo-random sequence is selected from the N pseudo-random sequences to participate in the modulation, and it has a certain probability, so that information can be carried. For example, a certain pseudo-random sequence is selected from 4 pseudo-random sequences, and the probability of any one pseudo-random sequence appearing is one quarter. From the theory of information, two bits of information can be carried, i.e
In the technical scheme disclosed by the embodiment of the invention, when the selection mapping module performs pseudo-random sequence selection mapping, each data combination of the p-bit selection mapping group is mapped into an ith pseudo-random sequence selected from N pseudo-random sequences generated by the pseudo-random sequence generation module to participate in modulation according to a one-to-one mapping relation, and the p and the N satisfy a relation: />
Sign->
Representing a rounding down. When n=4, p=2.
Preferably, in the technical solution disclosed in the embodiment of the present invention, the N pseudo-random sequences are bipolar pseudo-random sequences, two pairs of pseudo-random sequences are orthogonal or quasi-orthogonal, and the number of bits is M.
In the prior art, the pseudo-random sequence participates in modulating and loading information, and the information is carried by using the normal phase state and the reverse phase state of the pseudo-random sequence. Therefore, only 1bit information can be carried. In order to further improve the information carrying capacity of the system and improve the information transmission efficiency, the technical scheme disclosed by the embodiment of the invention abandons two states of normal phase and reverse phase related to the pseudo-random sequence in the prior art. The phase shift mapping module of the spread spectrum modulation unit utilizes the cyclic shift state of the pseudo-random sequence to realize loading information so as to increase the state number and improve the information carrying capacity. And performing cyclic shift on the pseudo-random sequence output by the selection mapping module, and realizing information loading for the 2 nd time, namely phase shift mapping by utilizing the cyclic shift state of the pseudo-random sequence. The cyclic shift of the pseudo-random sequence is cyclic left shift or cyclic right shift, and 1bit of data is cyclically shifted each time. In the technical scheme disclosed by the embodiment of the invention, the phase shift mapping module maps each data combination of the q-phase shift mapping group output by the data grouping module into a cyclic left shift state of the ith pseudorandom sequence according to a one-to-one mapping relationship, each data combination of the q-phase shift mapping group can only be mapped with one cyclic left shift state of the ith pseudorandom sequence, and the cyclic left shift states mapped by any two data combinations are different. Further, q and M satisfy the relation:
sign->
Representing a rounding down. For example, by selecting the number of bits of the mapped pseudo random sequence to be 8, i.e., m=8, q=3.
Further, in the technical scheme disclosed in the embodiment of the present invention, the data grouping module groups user data, where the grouping includes a p-bit selection mapping group and a q-bit shift mapping group; i.e. the user data is grouped by (p+q) bit size, said grouping comprising a p-bit selection map group and a q-bit shift map group.
Preferably, in the technical scheme disclosed in the embodiment of the present invention, the pseudo-random sequence generating module generates 4 bipolar orthogonal pseudo-random sequences, denoted as c 1 (t)、c 2 (t)、c 3 (t) and c 4 (t) the 4 pseudo-random sequences each comprise 8 bits of data. For example, a pseudo-random sequence c 2 (t) is-1, -1, -1, pseudo-random sequence c 2 (t) after cyclic shift, 8 pseudo-random sequences, denoted as c, respectively, can be formed 2,0 (t)、c 2,1 (t)、c 2,2 (t)、c 2,3 (t)、c 2,4 (t)、c 2,5 (t)、c 2,6 (t)、c 2,7 (t)。
Preferably, in the technical solution disclosed in the embodiment of the present invention, the data grouping module groups the user data according to a (2+3) bit size, that is, the grouping includes a 2bit selection mapping group and a 3bit phase shift mapping group. And the selection mapping module maps each data combination of the 2bit selection mapping group into a certain pseudo-random sequence selected from the 4 pseudo-random sequences to participate in modulation according to a one-to-one mapping relation, and each data combination of the 2bit selection mapping group can only be mapped with one pseudo-random sequence, wherein the mapping relation is shown in a table 1.
Table 1 mapping relationship between data combinations of selected mapping groups and pseudo-random sequences
| Data combination of 2bit selection map group | Pseudo-random sequence |
| 00 | c 1 (t) |
| 01 | c 2 (t) |
| 10 | c 3 (t) |
| 11 | c 4 (t) |
In the technical scheme disclosed in the embodiment of the invention, the one-to-one mapping relationship between the data combination of the 2-bit selection mapping group and the pseudo-random sequence realized by the selection mapping module is not limited to table 1, as long as each data combination in the 2-bit selection mapping group can be satisfied that only one pseudo-random sequence corresponds to the data combination, and the pseudo-random sequences corresponding to any two data combinations are different.
As shown in table 1, when the data combination of the 2bit selection mapping group is 01, the selection mapping module maps it to the 2 nd pseudo-random sequence, i.e., c 2 (t) whereby the loading of the data of the selection map group is completed, i.e. the selection map module represents the data combination in a pseudo random sequence. Generally, the number of bits of the pseudorandom sequence is greater than the number of bits of the data combination, thereby realizing spectrum spreading, reducing the power spectral density of the signal, improving the concealment capability of the signal and being difficult to detect by the detection device.
As described earlier, when the pseudo random sequence c 2 (t) is-1, -1, -1, and after cyclic shift, 8 pseudo-random sequences are formed, which can be represented as c respectively 2,0 (t)、c 2,1 (t)、c 2,2 (t)、c 2,3 (t)、c 2,4 (t)、c 2,5 (t)、c 2,6 (t)、c 2,7 (t), wherein c 2,0 (t)＝c 2,0 (t), an initial state; and the phase shift mapping module is used for finishing the loading of the information for the 2 nd time through phase shift mapping on the basis of the selection mapping module.
The phase shift mapping module maps each data combination of the 3bit phase shift mapping group into the 2 nd pseudo random sequence c according to a one-to-one mapping relation 2 (t) each data combination of the 3-bit phase shift map group can only be combined with the 2 nd pseudo-random sequence c 2 And (t) a cyclic shift state. The pseudo-random sequence c 2 (t) when cyclic left shift is adopted, the phase shift mapping module performs data combination of the 3bit phase shift mapping group and the 2 nd pseudo random sequence c according to a one-to-one mapping relation 2 The mapping relation of the cyclic shift state of (t) is shown in table 2.
Table 2 3bit phase shift map group data combination and c 2 (t) cyclic shift state mapping relation
| Sequence number | Data combination of 3bit phase shift mapping group | c 2 (t) cyclic |
| 1 | 000 | c 2,0 (t)＝-1,1,1,1,1,1,-1,-1 |
| 2 | 001 | c 2,1 (t)＝1,1,1,1,1,-1,-1,-1 |
| 3 | 010 | c 2,2 (t)＝1,1,1,1,-1,-1,-1,1 |
| 4 | 011 | c 2,3 (t)＝1,1,1,-1,-1,-1,1,1 |
| 5 | 100 | c 2,4 (t)＝1,1,-1,-1,-1,1,1,1 |
| 6 | 101 | c 2,5 (t)＝1,-1,-1,-1,1,1,1,1 |
| 7 | 110 | c 2,6 (t)＝-1,-1,-1,1,1,1,1,1 |
| 8 | 111 | c 2,7 (t)＝-1,-1,1,1,1,1,1,-1 |
In the technical scheme disclosed in the embodiment of the invention, in the phase shift mapping module, the data combination in the 3bit phase shift mapping group and the 2 nd pseudo random sequence c 2 The one-to-one mapping relationship of the cyclic left shift states of (t) is not limited to table 1, as long as each data combination in the phase shift mapping group can be satisfied that only one pseudo random sequence cyclic shift state corresponds to the data combination, and the pseudo random sequence cyclic shift states corresponding to any two data combinations are different.
As shown in table 2, in the phase shift mapping module, when the data combination of the 3bit phase shift mapping group is 001, the data combination is mapped to the 2 nd pseudo random sequence c 2 The 2 nd cyclic shift state of (t), i.e. c 2,1 (t) sequence c at this time 21 The numerical values of bits of (t) can be expressed as:
in the technical scheme disclosed in the embodiment of the invention, after the spread spectrum modulation unit finishes the selection mapping and the phase shift mapping, the selected mapping and the phase shift mapping are output to the pulse modulation unit, and the pulse modulation module adopts pulse amplitude modulation to carry out the 2 nd pseudorandom sequence c 2 The 2 nd cyclic left shift state c of (t) 2,1 Each bit of data of (t)
Sequentially loading the long spherical wave function gamma (t) and outputting an integration result to the nonlinear unit; the nonlinear unit takes the received integral signal as the additional phase of the third power nonlinear frequency modulation signal and generates a pseudo-random carrier frequency signal f according to the carrier frequency control module c And a pseudo-random phase signal generated by said phase control module +.>
And generating radar communication integrated signals and outputting the radar communication integrated signals to the power amplification unit. The radar communication integrated signal is:
wherein f c Is the carrier frequency of the radar communication integrated signal, B is the signal bandwidth factor, T is the signal time factor,
for the 2 nd pseudo-random sequence c 2 The 2 nd cyclic left shift state c of (t) 2,1 The j-th bit of data of (t), j is a positive integer, j=1, 2, …, and γ (t) is a 0 th order long spherical wave function.
In the technical scheme disclosed by the embodiment of the invention, the generated radar communication integrated signal expands the signal spectrum, so that the concealment of the radar signal is enhanced, the capability of resisting deceptive interference is improved, the forwarding interference can be converted into low-power spectral noise, the capability of resisting forwarding interference is obviously improved, the capability of resisting compression type interference is improved through pseudo-random agility of pulse carrier frequencies, the radar signal has the characteristics of constant envelope and low peak-to-average ratio, the power utilization rate of a radar power amplification system is improved, the detection performance of the radar on a target is ensured, and meanwhile, on the basis, information transmission efficiency of the system is improved by adopting three modes of selecting mapping, phase-shifting mapping and pulse amplitude, and the problems existing in the prior art are solved.
Claims (10)
1. The radar communication integrated signal generating device based on pulse frequency agility is characterized by comprising a spread spectrum modulation unit, a pulse modulation unit, a nonlinear unit and a power amplification unit;
the spread spectrum modulation unit receives user data, loads the data to a pseudo-random sequence through data grouping, selection mapping and phase shift mapping to realize spread spectrum modulation, and outputs the data to the pulse modulation unit;
the pulse modulation unit completes pulse amplitude modulation and outputs the pulse amplitude modulation to the nonlinear unit after integration;
the nonlinear unit generates radar communication integrated signals with a carrier frequency and a phase being pseudo-randomly variable based on the third power nonlinear frequency modulation signals and outputs the radar communication integrated signals to the power amplification unit;
and the power amplification unit performs power amplification on the received signal and outputs the power amplified signal to the antenna.
2. The pulse frequency agile based radar communication integrated signal generating device of claim 1, wherein the spread spectrum modulation unit comprises a data grouping module, a pseudo random sequence generating module, a selection mapping module, and a phase shift mapping module;
the data grouping module groups the received user data, wherein the grouping comprises a p-bit selection mapping group and a q-bit shift mapping group, the p-bit selection mapping group is output to the selection mapping module, and the q-bit shift mapping group is output to the phase shift mapping module;
the pseudo-random sequence generating module is used for generating N pseudo-random sequences which are orthogonal or quasi-orthogonal in pairs and have M digits, and outputting the N pseudo-random sequences to the selection mapping module;
the selection mapping module maps each data combination of the p-bit selection mapping group into an ith pseudo-random sequence selected from the N pseudo-random sequences according to a one-to-one mapping relation, and outputs the ith pseudo-random sequence to the phase shift mapping module;
and the phase shift mapping module maps each data combination of the q-phase shift mapping group into a cyclic shift state of the ith pseudo-random sequence according to a one-to-one mapping relation, and outputs the cyclic shift state to the pulse modulation unit.
3. The radar communication integrated signal generating apparatus based on pulse frequency agility according to claim 2, wherein the pulse modulation unit comprises a pulse waveform generating module, a pulse amplitude modulation module, and an integrating module;
the pulse waveform generation module is used for generating a pulse waveform gamma (t) and outputting the pulse waveform gamma (t) to the pulse amplitude modulation module;
the pulse amplitude modulation module is connected with the phase shift mapping module, and is used for loading each bit of data in the ith pseudorandom sequence cyclic shift state onto the pulse waveform gamma (t) in sequence and outputting the data to the integration module;
the integration module integrates the received signals and outputs the integrated signals to the nonlinear unit.
4. The pulse frequency agile based radar communication integrated signal generating device of claim 3, wherein the nonlinear unit comprises a carrier frequency control module, a phase control module, and a nonlinear modulation module;
the carrier frequency control module is used for generating a pseudo-random carrier frequency signal f c And output to the nonlinear modulation module;
the phase control module is used for generating pseudo-random phase signals
And output to the nonlinear modulation module;
the nonlinear modulation module is connected with the integration module and takes the received integrated signal as an additional phase of a third power nonlinear frequency modulation signal; the nonlinear modulation module is used for modulating the carrier frequency signal according to the pseudo-random carrier frequency signal f c And the pseudo-random phase signal
The method comprises the steps of generating radar communication integrated signals and outputting the radar communication integrated signals to the power amplification unit, wherein the radar communication integrated signals are as follows:
wherein f c Is the carrier frequency of the radar communication integrated signal, B is the signal bandwidth factor, T is the signal time factor,
the j-th bit data of the kth cyclic shift state of the ith pseudo-random sequence participating in modulation, k is a positive integer, k=0, 1,2, … M-1, j is a positive integer, j=1, 2, … M.
5. The pulse frequency agile based radar communication integrated signal generating device of claim 4, wherein the pseudo-random phase signal generated by the phase control module
Is in the range of [ -pi, pi]And is statistically independent between each bit of data of the ith pseudorandom sequence cyclic shift state.
6. The pulse frequency agile based radar communication integrated signal generation device of claim 4, wherein the carrier frequency control module generates a pseudo-random carrier frequency signal f c Is a slave hopping sequence [ f 1 ,f 2 ,…,f M ]And is statistically independent between each bit of data of the ith pseudorandom sequence cyclic shift state.
7. The pulse frequency agile based radar communication integrated signal generating device of claim 4, wherein the cyclic shift is a cyclic left shift or a cyclic right shift, each cyclic shift being 1bit of data.
8. The pulse frequency agile based radar communication integrated signal generating device of claim 4, wherein the number of bits p of the selection map set and the number of pseudo random sequences N satisfy a relationship:
sign->
Representing a rounding down.
9. The pulse frequency agile based radar communication integrated signal generating device of claim 4, wherein the number of bits q of the phase shift map set and the number of bits M of the pseudo random sequence satisfy the relationship:
sign->
Representing a rounding down.
10. The pulse-frequency agile radar communication integrated signal producing device according to claim 4, wherein the pulse waveform γ (t) is a 0 th order long spherical wave function.
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