CN115079149A - Double-chirp-rate microwave photon dual-band radar detection method and device - Google Patents

Double-chirp-rate microwave photon dual-band radar detection method and device Download PDF

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CN115079149A
CN115079149A CN202210727578.1A CN202210727578A CN115079149A CN 115079149 A CN115079149 A CN 115079149A CN 202210727578 A CN202210727578 A CN 202210727578A CN 115079149 A CN115079149 A CN 115079149A
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王祥传
曹冯婷
潘时龙
马丛
杨悦
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Nanjing University of Aeronautics and Astronautics
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Nanjing University of Aeronautics and Astronautics
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/282—Transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/285—Receivers
    • G01S7/292—Extracting wanted echo-signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/36—Means for anti-jamming, e.g. ECCM, i.e. electronic counter-counter measures

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  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

The invention discloses a double-chirp-rate microwave photon dual-band radar detection method, and belongs to the technical field of radars. At a transmitting end, an optical carrier is divided into two paths, one path is modulated by a linear frequency modulation microwave signal to generate a modulated optical signal, and the other path is not modulated; rotating the polarization state of any path, coupling to generate orthogonal polarized light signals, and dividing the orthogonal polarized light signals into two paths; one path is used as a reference light signal of a receiver, and the other path is converted into a linearly polarized light signal and subjected to photoelectric detection to generate a dual-chirp-rate dual-waveband signal; at a receiving end, the reference optical signal is further divided into two paths, and one path is modulated by a target echo signal after being filtered; the other path of the optical signal in the two polarization states is coupled with the target modulation optical signal and is subjected to photoelectric detection to generate a deskew signal; and carrying out signal processing on the dual-waveband deskew signal to realize high-resolution detection. The invention also discloses a double-chirp rate microwave photon dual-waveband radar detection device. Compared with the prior art, the invention has better anti-interference capability.

Description

Double-chirp-rate microwave photon dual-band radar detection method and device
Technical Field
The invention relates to the technical field of radars, in particular to a dual-chirp-rate microwave photon dual-band radar detection method and device.
Background
High-resolution detection of complex targets and acquisition of complete observation information are particularly important in radars. The dual-band radar system can work in different bands, acquire the electromagnetic scattering characteristics of targets in different frequency bands and collect more complete target characteristic information. The received two wave band signals can be fused through digital signal processing, the resolution and the recognition capability of target detection are further improved, and the method has great significance in the applications of radar small target detection and tracking, multi-target detection and separation, high-resolution imaging and the like. In addition, when the dual-band radar can transmit signals with different chirp rates, the anti-interference capability of the radar can be improved. However, the traditional radar adopting electronic technology is limited by bandwidth bottleneck, and is difficult to realize the generation and processing of dual-band radar signals on the same system, thereby causing resource waste.
Compared with the electronic technology, the microwave photon technology has the advantages of large bandwidth, low transmission loss, electromagnetic interference resistance and the like, for example, the frequency and the bandwidth of a microwave signal can be doubled by means of the microwave photon frequency doubling technology; by converting the microwave signal to the optical domain for processing, the radar transceiver can generate and process a large bandwidth signal in real time. Currently, there are reports of dual-band radar using microwave photon Technology, but the current implementation requires two microwave signals with different parameters to drive the system, which is complex and costly (see [ Peng S, Li S, Xue X, et al, "a Photonics-based coherent dual-band radar for super-resolution profile," IEEE Photonics Journal,2019,11(4):1-8.] [ Cao J, Li R, Yang J, et al, "Photonic radar receiver for dual-band LFM-CW radar," Journal of light Technology,2019,37(10): 2403-. Therefore, the research on the dual-chirp-rate microwave photon dual-band broadband radar which is simple in structure and easy to realize has very important significance for enriching the detection function of the radar and improving the range resolution and the anti-interference capability of the radar.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a dual-chirp rate microwave photon dual-band radar detection method, which can simultaneously generate dual-band signals of dual chirp rates and realize deskew receiving and bandwidth fusion, thereby realizing anti-interference broadband microwave detection/imaging.
A dual chirp rate microwave photon dual-band radar detection method,
at a transmitting end, a linear frequency modulation microwave signal is used for carrying out carrier suppression double-sideband modulation on one path of optical carrier, the generated carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are polarized and coupled into one path of orthogonal polarization optical signal, the carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are respectively in two orthogonal polarization states of the orthogonal polarization optical signal, and the phase of the optical carrier and the two sidebands in the orthogonal polarization optical signal meet the relationship: delta theta up -Δθ down Not equal to 2n pi + pi/2, wherein, Delta theta up Δ θ, the phase difference between the optical carrier and the upper sideband down Is the phase difference between the optical carrier and the lower sideband, and n is an integer; dividing the orthogonal polarized light signal into two paths, wherein one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal through an analyzer; performing photoelectric conversion on the linearly polarized light signal to generate a dual-band radar signal with chirp rates of k and 2k, and transmitting the dual-band radar signal by a transmitting antenna at the same time, wherein k is the chirp rate of the linear frequency modulation microwave signal;
at a receiving end, dividing a reference optical signal into two paths, and separating signals in two polarization states of one path of the reference optical signal to generate two local oscillation optical signals; filtering out a side band of the other path of reference optical signal, and carrying out carrier suppression double-sideband modulation on the reference optical signal by using a target echo signal to generate a target modulation optical signal; dividing a target modulation optical signal into two paths, performing optical mixing with two local oscillation optical signals respectively, and performing balanced photoelectric detection on the obtained optical signals to obtain two deskew signals with frequencies of k tau and 2k tau respectively, wherein tau is the time delay between a target echo signal and a transmitting signal; and finally, performing signal processing on the two deskew signals to obtain target information.
Based on the same inventive concept, the following technical scheme can be obtained:
a dual chirp rate microwave photon dual-band radar detection device comprises a transmitting end and a receiving end;
at a transmitting end, a linear frequency modulation microwave signal is used for carrying out carrier suppression double-sideband modulation on one path of optical carrier, the generated carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are polarized and coupled into one path of orthogonal polarization optical signal, the carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are respectively in two orthogonal polarization states of the orthogonal polarization optical signal, and the phase of the optical carrier and the two sidebands in the orthogonal polarization optical signal meet the relationship: delta theta up -Δθ down Not equal to 2n pi + pi/2, wherein, Delta theta up Δ θ, the phase difference between the optical carrier and the upper sideband down Is the phase difference between the optical carrier and the lower sideband, and n is an integer; dividing the orthogonal polarized light signal into two paths, wherein one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal through an analyzer; performing photoelectric conversion on the linearly polarized light signals to generate dual-band radar signals with chirp rates of k and 2k, and simultaneously transmitting the signals by a transmitting antenna, wherein k is the chirp rate of the linear frequency modulation microwave signals;
at a receiving end, dividing a reference optical signal into two paths, and separating signals in two polarization states of one path of the reference optical signal to generate two local oscillation optical signals; filtering out a side band of the other path of reference optical signal, and carrying out carrier suppression double-sideband modulation on the reference optical signal by using a target echo signal to generate a target modulation optical signal; dividing a target modulation optical signal into two paths, performing optical mixing with two local oscillation optical signals respectively, and performing balanced photoelectric detection on the obtained optical signals to obtain two deskew signals with frequencies of k tau and 2k tau respectively, wherein tau is the time delay between a target echo signal and a transmitting signal; and finally, performing signal processing on the two deskew signals to obtain target information.
Preferably, the signal processing is specifically as follows: carrying out sampling rate conversion processing on one of the deskew signals to enable the frequency of the deskew signal to be the same as that of the other deskew signal; then, phase correction is carried out on the two deskew signals with the same frequency; and finally, reconstructing a full-band deskew signal through compressed sensing.
Preferably, the carrier suppression double sideband modulation is performed on one path of optical carrier by using a chirp microwave signal, and the generated carrier suppression double sideband modulation optical signal and another path of homologous optical carrier are polarization-coupled into one path of orthogonal polarization optical signal, which is realized by using a dual-polarization intensity modulator.
Preferably, the optical mixing is realized by two identical optical mixers or by two identical 2 x 2 optical couplers.
Preferably, the target modulated optical signal is generated by an intensity modulator operating at a minimum bias point.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
1. the invention adopts a microwave driving signal to realize the generation of dual-waveband signals, can effectively reduce the system cost, and has simple and easy control.
2. The invention breaks through the limitation of the traditional electronic technology to the system bandwidth, and the equivalent bandwidth of the generated radar signal is larger than that of the original microwave signal.
3. The system simultaneously generates two dual-band microwave signals with different chirp rates, and can simultaneously process the signals, thereby improving the anti-interference capability of the radar.
4. The radar works in two frequency bands, and after receiving, the signals received by the two frequency bands can be separated, so that the application of the radar is expanded.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of a dual chirp rate microwave photon dual band radar detection apparatus according to the present invention;
FIG. 2 is a schematic structural diagram of another embodiment of the dual chirp rate microwave photon dual band radar detection apparatus of the present invention;
FIG. 3 is a schematic diagram of a structure of a dual-polarization intensity modulator;
FIG. 4 is a schematic diagram of a spectrum of an output signal of a dual polarization intensity modulator;
FIG. 5 is a schematic diagram of a time-frequency curve for dual-band signal deskewing.
Detailed Description
A dual chirp rate microwave photon dual-band radar detection method,
at a transmitting end, a linear frequency modulation microwave signal is used for carrying out carrier suppression double-sideband modulation on one path of optical carrier, the generated carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are polarized and coupled into one path of orthogonal polarization optical signal, the carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are respectively in two orthogonal polarization states of the orthogonal polarization optical signal, and the phase of the optical carrier and the two sidebands in the orthogonal polarization optical signal meet the relationship: delta theta up -Δθ down Not equal to 2n pi + pi/2, wherein, Delta theta up Δ θ, the phase difference between the optical carrier and the upper sideband down Is the phase difference between the optical carrier and the lower sideband, and n is an integer; dividing the orthogonal polarized light signal into two paths, wherein one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal through an analyzer; performing photoelectric conversion on the linearly polarized light signals to generate dual-band radar signals with chirp rates of k and 2k, and simultaneously transmitting the signals by a transmitting antenna, wherein k is the chirp rate of the linear frequency modulation microwave signals;
at a receiving end, dividing a reference optical signal into two paths, and separating signals in two polarization states of one path of the reference optical signal to generate two local oscillation optical signals; filtering out a side band of the other path of reference optical signal, and carrying out carrier suppression double-sideband modulation on the reference optical signal by using a target echo signal to generate a target modulation optical signal; dividing a target modulation optical signal into two paths, performing optical mixing with two local oscillation optical signals respectively, and performing balanced photoelectric detection on the obtained optical signals to obtain two deskew signals with frequencies of k tau and 2k tau respectively, wherein tau is the time delay between a target echo signal and a transmitting signal; and finally, performing signal processing on the two deskew signals to obtain target information.
Based on the same inventive concept, the following technical scheme can be obtained:
a dual chirp rate microwave photon dual-band radar detection device comprises a transmitting end and a receiving end;
at a transmitting end, a linear frequency modulation microwave signal is used for carrying out carrier suppression double-sideband modulation on one path of optical carrier, the generated carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are polarized and coupled into one path of orthogonal polarization optical signal, the carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are respectively in two orthogonal polarization states of the orthogonal polarization optical signal, and the phase of the optical carrier and the two sidebands in the orthogonal polarization optical signal meet the relationship: delta theta up -Δθ down Not equal to 2n pi + pi/2, wherein, Delta theta up Δ θ, the phase difference between the optical carrier and the upper sideband down Is the phase difference between the optical carrier and the lower sideband, and n is an integer; dividing the orthogonal polarized light signal into two paths, wherein one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal through an analyzer; performing photoelectric conversion on the linearly polarized light signals to generate dual-band radar signals with chirp rates of k and 2k, and simultaneously transmitting the signals by a transmitting antenna, wherein k is the chirp rate of the linear frequency modulation microwave signals;
at a receiving end, dividing a reference optical signal into two paths, and separating signals in two polarization states of one path of the reference optical signal to generate two local oscillation optical signals; filtering out a side band of the other path of reference optical signal, and carrying out carrier suppression double-sideband modulation on the reference optical signal by using a target echo signal to generate a target modulation optical signal; dividing a target modulation optical signal into two paths, performing optical mixing with two local oscillation optical signals respectively, and performing balanced photoelectric detection on the obtained optical signals to obtain two deskew signals with frequencies of k tau and 2k tau respectively, wherein tau is the time delay between a target echo signal and a transmitting signal; and finally, performing signal processing on the two deskew signals to obtain target information.
The signal processing can adopt various existing technologies, for example, two deskew signals are respectively processed by using a traditional method to obtain target information, and then more accurate target information is obtained in an information fusion mode; in order to more effectively utilize two different frequency deskew signals to expand the deskew signal bandwidth, the signal processing is preferably as follows: carrying out sampling rate conversion processing on one of the deskew signals to enable the frequency of the deskew signal to be the same as that of the other deskew signal; then, phase correction is carried out on the two deskew signals with the same frequency; and finally, reconstructing a full-band deskew signal through compressed sensing.
The generation of the orthogonally polarized optical signals can be achieved by using a plurality of independent device combinations, such as one intensity modulator, an optical fiber and a plurality of optical couplers, but the method can seriously affect the phase noise of the generated signals and weaken the reconfigurability of the system; two intensity modulators and polarization rotators may also be used; in order to make the system structure more compact, the adjustment more convenient, and the system coherence better, preferably, the carrier suppression double sideband modulation is performed on one path of optical carrier by using the chirp microwave signal, and the generated carrier suppression double sideband modulation optical signal and another path of homologous optical carrier are polarization-coupled into one path of orthogonal polarization optical signal, which is realized by using a dual-polarization intensity modulator.
Preferably, the optical mixing is realized by two identical optical mixers (both 90 ° or 180 ° optical mixers), or by two identical 2 × 2 optical couplers.
Preferably, the target modulated optical signal is generated by an intensity modulator operating at a minimum bias point.
For the public understanding, the technical scheme of the invention is explained in detail by the specific embodiment and the attached drawings:
FIG. 1 shows a specific implementation structure of the dual chirp rate microwave photon dual band radar detection device of the present invention, which includes a transmitting end and a receiving end; the transmitting end comprises a laser, a dual-polarization intensity modulator, an optical coupler, an analyzer, an optical filter, a photoelectric detector, a transmitting antenna and an electric signal generator. As shown in fig. 1, the optical carrier generated by the laser is divided into two paths; the electric signal emitter generates a linear frequency modulation microwave signal with chirp rate k, and the linear frequency modulation microwave signal modulates one path of optical carrier generated by the laser through the dual-polarization intensity modulator to generate a carrier suppression dual-sideband modulation optical signal; the other path of optical carrier generated by the laser is output after being subjected to phase control through the dual-polarization intensity modulator, and is coupled into one path through a polarization rotator in the dual-polarization intensity modulator to obtain an orthogonal polarization optical signal containing a carrier optical signal and a carrier suppression dual-sideband modulation optical signal, wherein the carrier suppression dual-sideband modulation optical signal and the optical carrier are respectively positioned on two orthogonal polarization states of the orthogonal polarization optical signal; the orthogonal polarized light signal is divided into two paths by an optical coupler, one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal by an analyzer; the linearly polarized light signal generates a dual-band radar signal with chirp rates of k and 2k after being subjected to frequency beating in a photoelectric detector, and the dual-band radar signal is transmitted by a transmitting antenna simultaneously.
As shown in fig. 1, the receiving end includes an optical filter, a receiving antenna, an intensity modulator, a polarization controller, a polarization beam splitter, an optical coupler, an optical mixer, a balanced photodetector, and a signal processing module; the reference optical signal is divided into two paths, one path of the reference optical signal is filtered out of one side band by an optical filter, a target echo signal is modulated and outputs a target modulated optical signal in the intensity modulator, and the target modulated optical signal is divided into two paths by the optical coupler; the polarization controller is used for adjusting the polarization state of the other path of reference optical signal, so that one polarization direction of the reference optical signal is aligned to one of the main shafts of the polarization beam splitter, and the polarization beam splitter is used for separating the path of reference optical signal into local oscillation optical signals in two polarization states; the local oscillation optical signal and the target modulation optical signal are respectively subjected to optical mixing through two identical optical mixers, the obtained four paths of optical mixing signals are sent to a balanced photoelectric detector for beat frequency, two deskew signals with the frequencies of k tau and 2k tau are obtained, tau is the time delay between the target echo signal and the transmitting signal, and therefore deskew receiving of the two-waveband signal is achieved; the signal processing module carries out sampling rate conversion processing on one of the deskew signals to enable the frequency of the deskew signal to be the same as that of the other deskew signal; then, phase correction is carried out on the two deskew signals with the same frequency; and finally, reconstructing a full-band deskew signal through compressed sensing.
Fig. 2 shows a specific implementation structure of the dual chirp rate microwave photonic dual-band radar detection device of the present invention, which is substantially the same as the structure of fig. 1 except that the optical mixing is implemented using two identical 2 × 2 optical couplers.
For a better understanding of the technical solution and its technical effects, the principle of the present invention will be described in further detail with reference to the structure shown in fig. 2:
assuming that the optical carrier generated by the laser is
E in (t)＝E 0 exp(j2πf 0 t) (1)
Wherein E is 0 Is the amplitude of the optical signal, f 0 The center frequency of the optical signal. The optical signal is coupled into the dual polarization intensity modulator through the polarization controller.
Assuming that the electrical signal generator generates a chirp microwave signal of
V(t)＝V m cos(2πf RF t+πkt 2 ) (2)
Wherein, V m Is the amplitude of the signal, k is the chirp rate, f RF Is the center frequency. The microwave signal is input into an arm of a dual-polarization intensity modulator to modulate an optical carrier generated by a laser, and the structure and the principle of the dual-polarization intensity modulator are shown in fig. 3 and comprise two intensity modulators and a polarization rotator; generated carrier rejection double sideband
The modulated optical signal may be represented as
E X (t)∝exp(j2πf 0 t){exp[j(2πf RF t+πkt 2 )]+exp[-j(2πf RF t+πkt 2 )]} (3)
The other arm of the dual-polarization intensity modulator is not applied with a microwave driving signal, and the phase of the optical carrier is changed by controlling the bias voltage thereof, so that the phase is introduced
Figure BDA0003711486170000071
The carrier optical signal generated in this polarization state can be expressed as:
Figure BDA0003711486170000072
thus, the dual polarization intensity modulator produces an orthogonally polarized optical signal, the output signal of which has a spectrum as shown in FIG. 4. The orthogonal polarized light signal is divided into two paths by an optical coupler, one path is used as a reference light signal of a receiver, the other path is converted into a linearly polarized light signal by an analyzer, and the obtained signal can be expressed as:
E(t)∝E X (t)cosθ+E Y (t)sinθ (5)
wherein θ is the polarization detection angle of the polarization detector. After photoelectric conversion is implemented in the photodetector, the resulting radar emission signal can be expressed as:
Figure BDA0003711486170000073
wherein, a and b are both related to the polarization detection angle of the analyzer, and the polarization detection angle of the analyzer and the phase of the carrier optical signal are adjusted, so that two-waveband transmitting signals with the same amplitude and chirp rates divided into k and 2k can be obtained, and the amplitude of the two signals is not equal.
At a receiving end, the reference light signal is divided into two paths, and no time delay difference is assumed between paths through which the two paths of reference light signals are transmitted to the balanced photoelectric detector; after one path of the local oscillation optical signal passes through the polarization controller, the polarization beam splitter separates signals in two polarization states; the other path of the reference optical signal passes through an optical filter to filter out any side band, and the reference optical signal after filtering is not set as:
e(t)∝exp(j2πf 0 t)exp[j(2πf RF t+πkt 2 )](7) the receiving antenna receives the target echo as follows:
R(t)∝cos[2πf RF (t-τ)+πk(t-τ) 2 ]+cos[4πf RF (t-τ)+2πk(t-τ) 2 ] (8)
wherein tau is the time delay between the target echo and the radar emission signal. The echo signal is loaded on an intensity modulator of a receiver to modulate a reference optical signal. Adjusting direct current bias to enable the modulator to work at a minimum bias point, and realizing carrier suppression double-sideband modulation, wherein the output modulation signal is as follows:
Figure BDA0003711486170000081
the signal is separated by the optical coupler, and is respectively coupled with the local oscillator optical signals in two polarization states through the 2 multiplied by 2 optical coupler, and the output signal of the optical coupler is as follows:
Figure BDA0003711486170000082
wherein i represents the X-polarization state and the Y-polarization state.
Finally, the frequency beat of the balanced photoelectric detector is carried out to realize the deskew receiving of the echo signals of the dual-band radar
The equation can be expressed as:
Figure BDA0003711486170000083
the two resulting deskew signals are:
Figure BDA0003711486170000084
after fast Fourier transform, the frequencies of peak values in the obtained frequency spectrogram are k tau and 2k tau respectively; wherein k τ 2 The term is a residual video phase term and can not be considered in the fusion process.
The dual band signal deskew time frequency curve is shown in fig. 5, B is the bandwidth of the chirp microwave signal,
T p is the signal pulse width. The solid line in the higher frequency part of the graph is the time-frequency curve of the radar emission signal, the dotted line is the time-frequency curve of the echo signal, the dotted line in the low frequency part of the graph is the time-frequency relation curve of the deskew signal, wherein f de1 And f de2 Deskew signals corresponding to two bands respectivelyFrequencies k τ and 2k τ.
In signal processing, firstly, frequency correction is completed through sampling rate conversion processing, and a signal is obtained:
Figure BDA0003711486170000091
wherein, γ is the phase related parameter after the phase item correction of the remaining video is completed by the preprocessing. Time shifting the signals with the same frequency by the amount of time
Figure BDA0003711486170000092
And finishing phase correction, and performing coherent fusion on the two processed deskew signals. And finally, reconstructing the full-frequency-band de-inclined signal through a compressed sensing reconstruction theory.
The system realizes the simultaneous generation and receiving processing of dual-chirp-rate dual-band signals. Firstly, the dual-band signals are simultaneously used for radar detection, so that the working frequency range of the radar is widened; meanwhile, the radar transmits signals with different chirp rates, so that the anti-interference capability of the system is improved; in addition, the system can also realize the coherent fusion of dual-chirp-rate dual-waveband radar signals, so that the equivalent working bandwidth of the radar is enlarged, and the range resolution of radar detection/imaging is greatly improved.

Claims (10)

1. A dual chirp rate microwave photon dual band radar detection method is characterized in that,
at a transmitting end, a linear frequency modulation microwave signal is used for carrying out carrier suppression double-sideband modulation on one path of optical carrier, the generated carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are polarized and coupled into one path of orthogonal polarization optical signal, the carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are respectively in two orthogonal polarization states of the orthogonal polarization optical signal, and the phase of the optical carrier and the two sidebands in the orthogonal polarization optical signal meet the relationship: delta theta up -Δθ down Not equal to 2n pi + pi/2, wherein, Delta theta up Δ θ, the phase difference between the optical carrier and the upper sideband down Is the phase difference between the optical carrier and the lower sideband, and n is an integer; dividing the orthogonal polarized light signal into two paths, wherein one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal through an analyzer; performing photoelectric conversion on the linearly polarized light signals to generate dual-band radar signals with chirp rates of k and 2k, and simultaneously transmitting the signals by a transmitting antenna, wherein k is the chirp rate of the linear frequency modulation microwave signals;
at a receiving end, dividing a reference optical signal into two paths, and separating signals in two polarization states of one path of the reference optical signal to generate two local oscillation optical signals; filtering out a side band of the other path of reference optical signal, and carrying out carrier suppression double-sideband modulation on the reference optical signal by using a target echo signal to generate a target modulation optical signal; dividing a target modulation optical signal into two paths, performing optical mixing with two local oscillation optical signals respectively, and performing balanced photoelectric detection on the obtained optical signals to obtain two deskew signals with frequencies of k tau and 2k tau respectively, wherein tau is the time delay between a target echo signal and a transmitting signal; and finally, performing signal processing on the two deskew signals to obtain target information.
2. The dual chirp rate microwave photonic dual band radar detection method of claim 1, wherein the signal processing is specifically as follows: carrying out sampling rate conversion processing on one of the deskew signals to enable the frequency of the deskew signal to be the same as that of the other deskew signal; then, phase correction is carried out on the two deskew signals with the same frequency; and finally, reconstructing a full-band deskew signal through compressed sensing.
3. The dual-chirp-rate microwave photonic dual-band radar detection method of claim 1, wherein the dual-chirp-rate microwave detection method is implemented by using a dual-polarization intensity modulator to perform carrier-suppressed dual-sideband modulation on one path of optical carrier by using a chirp microwave signal, and polarization-coupling the generated carrier-suppressed dual-sideband modulated optical signal and another homologous optical carrier into one path of orthogonal polarized optical signal.
4. The dual chirp rate microwave photonic dual band radar detection method of claim 1, wherein the optical mixing is achieved by two identical optical mixers or by two identical 2 x 2 optical couplers.
5. The dual chirp rate microwave photonic dual band radar detection method of claim 1 wherein the target modulated optical signal is generated by an intensity modulator operating at a minimum bias point.
6. A dual chirp rate microwave photon dual-band radar detection device comprises a transmitting end and a receiving end; it is characterized in that the preparation method is characterized in that,
at a transmitting end, a linear frequency modulation microwave signal is used for carrying out carrier suppression double-sideband modulation on one path of optical carrier, the generated carrier suppression double-sideband modulation optical signal and another path of homologous optical carrier are polarized and coupled into one path of orthogonal polarization optical signal, the carrier suppression double-sideband modulation optical signal and the other path of homologous optical carrier are respectively in two orthogonal polarization states of the orthogonal polarization optical signal, and the phases of the optical carrier and the two sidebands in the orthogonal polarization optical signal satisfy the relationship: delta theta up -Δθ down Not equal to 2n pi + pi/2, wherein, Delta theta up Δ θ, the phase difference between the optical carrier and the upper sideband down Is the phase difference between the optical carrier and the lower sideband, and n is an integer; dividing the orthogonal polarized light signal into two paths, wherein one path is used as a reference light signal of a receiving end, and the other path is converted into a linearly polarized light signal through an analyzer; performing photoelectric conversion on the linearly polarized light signals to generate dual-band radar signals with chirp rates of k and 2k, and simultaneously transmitting the signals by a transmitting antenna, wherein k is the chirp rate of the linear frequency modulation microwave signals;
at a receiving end, dividing a reference optical signal into two paths, and separating signals in two polarization states of one path of the reference optical signal to generate two local oscillation optical signals; filtering out a side band of the other path of reference optical signal, and carrying out carrier suppression double-sideband modulation on the reference optical signal by using a target echo signal to generate a target modulation optical signal; dividing a target modulation optical signal into two paths, performing optical mixing with two local oscillation optical signals respectively, and performing balanced photoelectric detection on the obtained optical signals to obtain two deskew signals with frequencies of k tau and 2k tau respectively, wherein tau is the time delay between a target echo signal and a transmitting signal; and finally, performing signal processing on the two deskew signals to obtain target information.
7. The dual chirp rate microwave photonic dual band radar detection device of claim 6, wherein the signal processing is specifically as follows: carrying out sampling rate conversion processing on one of the deskew signals to enable the frequency of the deskew signal to be the same as that of the other deskew signal; then, phase correction is carried out on the two deskew signals with the same frequency; and finally, reconstructing a full-band deskew signal through compressed sensing.
8. The dual-chirp-rate microwave photonic dual-band radar detection device of claim 6, wherein the dual-chirp-rate microwave detection device is implemented by a dual-polarization intensity modulator, wherein a chirp microwave signal is used to perform carrier suppression dual-sideband modulation on one path of optical carrier, and the generated carrier suppression dual-sideband modulated optical signal and another homologous optical carrier are polarization-coupled into one path of orthogonal polarized optical signal.
9. The dual chirp rate microwave photonic dual band radar detection device of claim 6, wherein the optical mixing is achieved by two identical optical mixers or by two identical 2 x 2 optical couplers.
10. The dual chirp rate microwave photonic dual band radar detection apparatus of claim 6 wherein the target modulated optical signal is generated by an intensity modulator operating at a minimum bias point.
CN202210727578.1A 2022-06-24 2022-06-24 Double-chirp-rate microwave photon dual-band radar detection method and device Pending CN115079149A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115825950A (en) * 2022-11-10 2023-03-21 北京卫星信息工程研究所 Satellite-borne dual-band radar searching and tracking system
CN116338592A (en) * 2023-05-22 2023-06-27 之江实验室 Microwave photon radar system and detection method based on photon mixing technology

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115825950A (en) * 2022-11-10 2023-03-21 北京卫星信息工程研究所 Satellite-borne dual-band radar searching and tracking system
CN115825950B (en) * 2022-11-10 2023-11-14 北京卫星信息工程研究所 Satellite-borne dual-band radar searching and tracking system
CN116338592A (en) * 2023-05-22 2023-06-27 之江实验室 Microwave photon radar system and detection method based on photon mixing technology

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