Multi-frequency continuous wave coherent forwarding method and device
阅读说明：本技术 多频连续波相干转发方法和装置 (Multi-frequency continuous wave coherent forwarding method and device ) 是由 黎亮 杨亚 于 2020-07-15 设计创作，主要内容包括：本说明书提供一种多频连续波相干转发方法和装置,包括：采用雷达参考信号对接收到的雷达波信号进行下变频处理,得到基带信号；雷达波信号为多频连续波信号；雷达参考信号的频率与雷达波信号中的载波频率相近；对基带信号进行波形检测和参数估计,得到点频分量的相位和频率；根据各点频分量的相位和频率生成与基带信号相参的转发基带信号；采用雷达参考信号对转发基带信号进行上变频处理,生成转发信号并发射转发信号。在转发信号传播至一次波雷达时的功率大于反射信号的功率的情况下,一次雷达在目标距离较远的情况下仍然能够收到大于可探测功率强度的转发信号,因此一次雷达的探测距离可以比接收反射信号确定的探测距离要远很多。(The present specification provides a multi-frequency continuous wave coherent forwarding method and apparatus, comprising: performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; the radar wave signal is a multi-frequency continuous wave signal; the frequency of the radar reference signal is close to the carrier frequency in the radar wave signal; carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and frequency of the dot frequency component; generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of each point frequency component; and performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal to generate a forwarding signal and transmitting the forwarding signal. In the case that the power of the retransmitted signal propagating to the primary radar is larger than that of the reflected signal, the primary radar can still receive the retransmitted signal with a larger intensity than the detectable power when the target distance is far away, and therefore the detection distance of the primary radar can be far longer than the detection distance determined by receiving the reflected signal.)
1. A multi-frequency continuous wave coherent forwarding method is characterized by comprising the following steps:
performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; the radar wave signal is a multi-frequency continuous wave signal; the frequency of the radar reference signal is close to the carrier frequency in the radar wave signal;
carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and frequency of a midpoint frequency component of the baseband signal;
generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of each point frequency component;
and performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal to generate a forwarding signal and transmitting the forwarding signal.
2. The multi-frequency continuous wave coherent forwarding method of claim 1, wherein the coherent forwarding method is performed in a half-duplex mode, comprising:
in an observation time window, performing down-conversion processing on a received radar wave signal by adopting a radar reference signal, and performing waveform detection and parameter estimation on the baseband signal;
and in a forwarding time window, generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of the point frequency component, and performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal.
3. The multi-frequency continuous wave coherent forwarding method of claim 2, wherein the forwarding time window is larger than the observation time window.
4. A multi-frequency continuous wave coherent retransmission apparatus, comprising:
a frequency signal source for generating radar reference signals for up-conversion and down-conversion;
the down-conversion module is used for performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; the radar wave signal is a multi-frequency continuous wave signal;
the detection estimation module is used for carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and the frequency of the dot frequency component;
a forwarding baseband signal generating module, configured to generate a forwarding baseband signal coherent to the baseband signal according to the phase and frequency of each point-frequency component;
and the up-conversion module is used for performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal, generating a forwarding signal and transmitting the forwarding signal.
5. The multi-frequency continuous wave coherent forwarding device of claim 4, wherein:
comprises a transmitting-receiving antenna; the receiving and transmitting antenna is connected with the down-conversion module and the up-conversion module through a switch; the up-conversion module and the down-conversion module are alternatively conducted with the antenna, so that down-conversion processing and up-conversion processing are realized.
6. The multi-frequency continuous wave coherent forwarding device of claim 5, wherein:
the time for the up-conversion module to carry out up-conversion processing on the forwarding baseband signal is longer than the time for the down-conversion module to carry out down-conversion processing on the received radar wave signal.
7. A long-distance target detection system based on multi-frequency continuous waves is characterized by comprising a primary radar and a forwarding device arranged on a long-distance target;
the primary radar is used for transmitting radar wave signals; the radar wave signal is a multi-frequency continuous wave signal;
the forwarding device is used for performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and frequency of the dot frequency component; generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of the dot frequency component; performing up-conversion processing on the forwarding baseband signal by using the radar reference signal to generate a forwarding signal and transmitting the forwarding signal; the frequency of the radio frequency reference signal is close to the carrier frequency of the primary radar signal;
and the primary radar is also used for receiving the retransmission signal and determining the distance and the radial speed of the long-distance target according to the retransmission signal.
8. The long range target radar system of claim 7, wherein:
the forwarding device comprises a transceiving antenna;
the receiving and transmitting antenna is connected with the down-conversion module and the up-conversion module; the up-conversion module and the down-conversion module are alternately connected with the antenna to realize down-conversion processing and up-conversion processing.
9. The remote object detection system of claim 8, wherein:
the time for the up-conversion module to carry out up-conversion processing on the forwarding baseband signal is longer than the time for the down-conversion module to carry out down-conversion processing on the received radar wave signal.
10. The remote object detection system of claim 7, wherein:
the repeating device periodically generates the repeating signal according to the multi-frequency continuous wave signal.
Technical Field
The specification relates to the technical field of radar detection, in particular to a multi-frequency continuous wave coherent forwarding method and a forwarding device, and further relates to a long-distance target radar system based on multi-frequency continuous waves.
Background
The primary radar is a widely adopted technical system for target detection and motion parameter estimation, and detection and measurement are carried out by means of radar emission signals and corresponding target scattered echo signals. Limited by the influence of radar transmitting power, radar receiving sensitivity and target reflection cross section; the radar can only reach the design performance within a certain distance range.
How to realize target detection at longer distance by using one-time radar is a problem to be solved in order to keep the radar power not to increase. The solutions in the prior art are as follows: installing high-stability clock sources on both the radar and the remote target, and enabling the frequencies of the radar and the forwarding device to be approximately coherent by adopting the high-stability clock sources so as to enable the forwarded signals to have coherence; however, the adoption of the method needs to simultaneously set a high-stability clock source in the radar and the forwarding device, and the cost is higher; in addition, because of the relative motion between the long-distance target and the radar, there is a difference in doppler frequency between the transponder signal generated by the transponder device and the real echo signal, resulting in that the radar cannot process the transponder signal and the normal echo signal identically.
Disclosure of Invention
The present specification provides a multi-frequency continuous wave coherent forwarding method and apparatus, which are used for improving the detection distance of a primary radar to a long-distance target on the premise of not changing the transmitting power and the use mode of the primary radar.
The present specification provides a multi-frequency continuous wave coherent forwarding method, including:
performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; the radar wave signal is a multi-frequency continuous wave signal; the frequency of the radar reference signal is close to the carrier frequency in the radar wave signal;
carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and frequency of a midpoint frequency component of the baseband signal;
generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of the dot frequency component;
and performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal to generate a forwarding signal and transmitting the forwarding signal.
Optionally, the method for performing coherent forwarding in a half-duplex mode includes:
in an observation time window, performing down-conversion processing on a received radar wave signal by adopting a radar reference signal, and performing waveform detection and parameter estimation on the baseband signal;
and in a forwarding time window, generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of the point frequency component, and performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal.
Optionally, the forwarding time window is larger than the observation time window.
This specification provides a multi-frequency continuous wave coherent forwarding device, including:
a frequency signal source for generating radar reference signals for up-conversion and down-conversion;
the down-conversion module is used for performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; the radar wave signal is a multi-frequency continuous wave signal;
the detection estimation module is used for carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and the frequency of the dot frequency component;
a forwarding baseband signal generating module, configured to generate a forwarding baseband signal coherent to the baseband signal according to the phase and frequency of the dot frequency component;
and the up-conversion module is used for performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal, generating a forwarding signal and transmitting the forwarding signal.
Optionally, the multi-frequency continuous wave coherent forwarding device includes a transceiver antenna; the receiving and transmitting antenna is connected with the down-conversion module and the up-conversion module through a switch; the up-conversion module and the down-conversion module are alternatively conducted with the antenna, so that down-conversion processing and up-conversion processing are realized.
Optionally, the time for performing the up-conversion processing on the forwarding baseband signal by the up-conversion module is longer than the time for performing the down-conversion processing on the received radar wave signal by the down-conversion module.
The specification provides a long-distance target detection system based on multi-frequency continuous waves, which comprises a primary radar and a forwarding device arranged on a long-distance target;
the primary radar is used for transmitting radar wave signals; the radar wave signal is a multi-frequency continuous wave signal;
the forwarding device is used for performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal; carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and frequency of the dot frequency component; generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of the dot frequency component; performing up-conversion processing on the forwarding baseband signal by using the radar reference signal to generate a forwarding signal and transmitting the forwarding signal; the frequency of the radio frequency reference signal is close to the carrier frequency of the primary radar signal;
and the primary radar is also used for receiving the retransmission signal and determining the distance-speed of the long-distance target according to the retransmission signal.
Optionally, the forwarding device includes a transceiver antenna;
the receiving and transmitting antenna is connected with the down-conversion module and the up-conversion module; the up-conversion module and the down-conversion module are alternately connected with the antenna to realize down-conversion processing and up-conversion processing.
Optionally, the time for performing the up-conversion processing on the forwarding baseband signal by the up-conversion module is longer than the time for performing the down-conversion processing on the received radar wave signal by the down-conversion module.
Optionally, the repeating device periodically generates the repeating signal according to the multi-frequency continuous wave signal.
In the forwarding method provided in this specification, a forwarding baseband signal is a signal that is coherent with a baseband signal, and a radar reference signal used for down-conversion processing and a radar reference signal used for up-conversion processing are the same signal, so that a baseband signal obtained by performing up-conversion processing on the forwarding baseband signal and the radar reference signal is a signal that is coherent with a radar wave signal. In the case that the power of the retransmitted signal propagating to the primary radar is greater than that of the reflected signal, the primary radar can still receive the retransmitted signal with greater than recognizable power intensity when the target distance is far away, and therefore the detection distance of the primary radar can be far longer than the detection distance determined by receiving the reflected signal of the target.
In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention.
Fig. 1 is a flowchart of a multi-frequency continuous wave coherent forwarding method provided by an embodiment;
fig. 2 is a schematic diagram of a processing application partitioning method of a forwarding method according to an embodiment;
fig. 3 is a schematic structural diagram of a multi-frequency continuous wave coherent forwarding device provided by an embodiment;
wherein: the device comprises an 11-frequency signal source, a 12-down conversion module, a 13-detection estimation module, a 14-forwarding baseband signal generation module and a 15-up conversion module.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
The embodiment of the present specification provides a multi-frequency continuous wave coherent forwarding method, which is applied to a forwarding device of a long-distance target, so that the forwarding device can forward a received radar wave signal sent by a primary radar.
Before explaining the method and the device provided by the specification, firstly, the principle of realizing target detection by a primary radar is analyzed.
Assuming that the time phase function of a radar wave signal emitted by a primary radar and irradiated on a target is
Fig. 1 is a flowchart of a multi-frequency continuous wave coherent forwarding method according to an embodiment. As shown in fig. 1, the method provided by the present embodiment includes steps S101-S104.
S101: and performing down-conversion processing on the received radar wave signal by adopting a radar reference signal to obtain a baseband signal.
In step S101, the radar wave signal is transmitted by a primary radar, and includes a plurality of continuous wave signals of baseband frequencies. The radar reference signal is a high-frequency signal generated by a response frequency source and a frequency synthesizer in the forwarding device; the frequency of the radar reference signal is close to the carrier frequency in the radar wave signal; what is said here to be close is: the radar reference signal and the radar wave signal may have the same frequency and may have the same nominal value or a smaller frequency difference.
It is conceivable that, after down-conversion processing is performed on the received radar wave signal by using the radar reference signal, the frequency of any one of the point-frequency signals in the obtained baseband signal is the same as the frequency difference between the reference signal and the corresponding point-frequency component in the received radar signal, and the phase of the point-frequency signal is the same as the phase difference between the reference signal and the corresponding point-frequency component in the received radar signal.
Specifically, assume that the time phase function of the radar wave signal irradiated on the target is
It should be noted that the foregoing description hasFor expressing the baseband signal only, in practiceIs unknown, both in phase and frequency characteristics. S102: and carrying out waveform detection and parameter estimation on the baseband signal to obtain the phase and frequency of the midpoint frequency component of the baseband signal.
In step S102, various existing methods such as a periodogram method, an autoregressive method, and a MUSIC method may be used to perform waveform detection and parameter estimation on the baseband signal, and determine the phase and frequency of each electrical frequency signal.
Following the description in S101, analyzing the baseband signal to obtain the phase and frequency of the dot frequency component, i.e. determining the initial phase
S103: and generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of each point frequency component.
In step S103, the forwarding device generates a forwarding baseband signal that is coherent with the baseband signal based on the phase and frequency of each point frequency component. Forwarding baseband signals as
S104: and performing up-conversion processing on the forwarding baseband signal by adopting the radar reference signal to generate a forwarding signal and transmit the forwarding signal.
In step S104, the forwarding device performs up-conversion processing on the forwarding baseband signal again based on the radar reference signal to generate a forwarding signal. Repeating signals
The power of the retransmission signal generated in step S104 is greater than the power of the radar wave signal reflected by the target.
As can be seen from the above analysis, the repeating baseband signal is a signal that is coherent with the baseband signal, and the radar reference signal used for the down-conversion process and the radar reference signal used for the up-conversion process are the same signal, so the baseband signal obtained by performing the up-conversion process on the repeating baseband signal and the radar reference signal is a signal that is coherent with the radar wave signal.
The power of the retransmission signal sent in step S104 is greater than the power of the reflected signal reflected by the remote target. The power of the forwarded signal when propagating to the primary radar is also larger than that of the reflected signal, and under the condition that the identification sensitivity of the primary radar is determined, the detection distance of the primary radar for detecting the long-distance target can be far longer than the detection distance determined by receiving the reflected signal.
After the forwarding device provided by the embodiment is adopted, the detection distance of the primary radar to the remote target provided with the forwarding device can be enlarged only by enabling the forwarding device to generate the forwarding signal according to the received radar wave signal under the conditions of not enlarging the transmitting frequency of the primary radar, not changing the working mode of the radar and not using a high-stability clock source.
Fig. 2 is a schematic diagram of a processing application partitioning method of a forwarding method according to an embodiment. As shown in fig. 2, in this embodiment, the forwarding device periodically executes the foregoing forwarding method, and the execution period is Tcy(ii) a In an execution period, the forwarding device works in a half-duplex transceiving mode, and a window time for acquiring the radar wave signal (i.e. a time for performing down-conversion processing on the received radar wave signal) is TmsThe time for executing step S102 is Tpc(i.e., time for frequency and phase estimation), the window time for generating the repeating signal is Tpd(i.e., the time at which the forwarded baseband signal is up-converted).
That is, the foregoing method is performed in half-duplex mode: in an observation time window, performing down-conversion processing on a received radar wave signal by adopting a radar reference signal, and performing waveform detection and parameter estimation on a baseband signal; and in the forwarding time window, generating a forwarding baseband signal coherent with the baseband signal according to the phase and the frequency of the point frequency component, and performing up-conversion processing on the forwarding baseband signal by adopting a radar reference signal.
It is contemplated that the forwarding device periodically performs the aforementioned forwarding method to avoid error accumulation caused by mismatching of the parameter estimation in step S102 with a change in the radar position of the long-distance target, a change in the speed of the long-distance target, and the like. The forwarding device adopts a half-duplex working mode, the power of the forwarding signal can be improved as required, the forwarding device is prevented from generating self excitation, and the effect of improving the radar detection distance is achieved.
As shown in FIG. 2, the window time for generating the retransmission signal is TpdThe window time greater than the acquisition of radar wave signal is TmsThe influence of the discontinuity of the forwarded signals on the primary radar detection can be reduced, and the effective tracking of the long-distance target flight state is realized.
In addition to providing the foregoing forwarding method, the present embodiment also provides a multi-frequency continuous wave coherent forwarding apparatus. Fig. 3 is a schematic structural diagram of a multi-frequency continuous wave coherent forwarding device according to an embodiment. As shown in fig. 3, the forwarding apparatus includes a frequency signal source 11, a down-conversion module 12, a detection estimation module 13, a forwarding baseband signal generation module 14, and an up-conversion module 15.
The frequency signal source 11 is used to generate radar reference signals for up-conversion and down-conversion. In one embodiment, the frequency signal source 11 may include a radio frequency source and a frequency synthesizer, and the frequency synthesizer forms the radar reference signal according to a reference frequency generated by the radio frequency source. A radar reference signal is a signal that is nominally the same as the carrier frequency in the primary radar.
The down-conversion module 12 is configured to perform frequency conversion processing on the received radar wave signal by using a radar reference signal to obtain a baseband signal.
The detection estimation module 13 is configured to perform waveform detection and parameter estimation on the baseband signal to obtain a phase and a frequency of each dot frequency component. In practical applications, the detection and estimation module 13 may perform waveform detection and parameter estimation on the baseband signal by using various possible methods such as a periodogram method, an autoregressive method, and a MUSIC method, so as to determine the phase and frequency of each electrical frequency signal.
The repeating baseband signal generating module 14 is configured to generate a repeating baseband signal coherent with the baseband signal according to the phase and frequency of the point-frequency component.
The up-conversion module 15 is configured to perform up-conversion processing on the forwarding baseband signal by using the radar reference signal, generate a forwarding signal, and transmit the forwarding signal.
As in the foregoing forwarding method, the power of the forwarding signal generated by the forwarding device provided in this embodiment is greater than the reflected signal formed by the radar wave signal reflected by the long-distance target, so that the detection distance of the primary radar to the long-distance target can be further increased.
In this embodiment, the forwarding device includes a transceiver antenna; the receiving and transmitting antenna is connected with the down-conversion module 12 and the up-conversion module 15 through a switch; by turning off the switch, the up-conversion module 15 and the down-conversion module 12 are alternately turned on with the antenna, thereby implementing the down-conversion process and the up-conversion process.
As described in the foregoing method, in this embodiment, the time for the up-conversion module 15 to up-convert the forwarding baseband signal is longer than the time for the down-conversion module 12 to down-convert the received radar wave signal.
The embodiment of the specification further provides a long-distance target detection system based on the multi-frequency continuous wave. The detection system comprises a primary radar and a transponder mounted on a distant target.
Primary radars are used to transmit radar wave signals. The radar wave signal is a multi-frequency continuous wave signal.
The forwarding device comprises a frequency signal source 11, a down-conversion module 12, a detection estimation module 13, a forwarding baseband signal generation module 14 and an up-conversion module 15. The frequency signal source 11 is used to generate radar reference signals for up-conversion and down-conversion. In one embodiment, the frequency signal source 11 may include a radio frequency source and a frequency synthesizer, and the frequency synthesizer forms the radar reference signal according to a reference frequency generated by the radio frequency source. A radar reference signal is a signal that is nominally the same as the carrier frequency in the primary radar.
The down-conversion module 12 is configured to perform frequency conversion processing on the received radar wave signal by using a radar reference signal to obtain a baseband signal.
The detection estimation module 13 is configured to perform waveform detection and parameter estimation on the baseband signal to obtain a phase and a frequency of each dot frequency component. In practical application, the detection and estimation module 13 may perform waveform detection and parameter estimation on the baseband signal by using various possible methods such as a periodogram method, an autoregressive method, and a MUSIC method, and determine the phase and frequency of each dot frequency signal.
The repeating baseband signal generating module 14 is configured to generate a repeating baseband signal coherent with the baseband signal according to the phase and frequency of the point-frequency component.
The up-conversion module 15 is configured to perform up-conversion processing on the forwarding baseband signal by using the radar reference signal, generate a forwarding signal, and transmit the forwarding signal.
After the primary radar receives the forwarding signal, the distance and/or the speed of the long-distance target can be determined according to the forwarding signal. Specifically, after the primary radar receives the forwarding signal, the forwarding signal is subjected to down-conversion processing, so that the distance and the speed of the long-distance target are determined according to the forwarding baseband signal.
In a specific application, the forwarding device may include a transceiver antenna; the up-conversion module 15 and the down-conversion module 12 are connected with the transceiving antenna through a switch, and the switch-on and switch-off of the up-conversion module and the down-conversion module with the transceiving antenna are realized through the switch-off of the switch, so that the down-conversion processing and the up-conversion processing are realized.
As before, in this embodiment, the time for the up-conversion module 15 to up-convert the forwarding baseband signal is longer than the time for the down-conversion module 12 to down-convert the received radar wave signal; the forwarding device periodically generates a forwarding signal according to the multi-frequency contact wave signal.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
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