Photon device and method for simultaneously measuring Doppler frequency shift and angle of arrival

Abstract

The invention discloses a photon device and method for simultaneously measuring Doppler frequency shift and an angle of arrival, and belongs to the technical field of microwave photon-assisted radars. The device is configured to enable a transmitting signal and a reference signal to enter a first dual-parallel Mach-Zehnder modulator working in a carrier suppression single sideband modulation mode after being combined so as to generate two positive first-order sideband signals, and then the two positive first-order sideband signals enter a second dual-parallel Mach-Zehnder modulator and are modulated by an echo signal; and a modulation signal output from the second dual-parallel Mach-Zehnder modulator enters a photoelectric detector for photoelectric conversion to generate a down-conversion signal. Comparing the frequency of the down-conversion signal with the frequency of the reference signal by using an electric spectrum analyzer to obtain the magnitude and direction of Doppler frequency shift; the arrival angle of the target can be obtained by monitoring the power of the frequency conversion signal. Measurement of Doppler frequency shift and the angle of arrival can be completed only by using the photoelectric detector with the bandwidth lower than the frequency of the transmitted signal, and the requirement for the bandwidth of the photoelectric detector is lowered.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave photons, and in particular relates to a photon device and method for simultaneously measuring Doppler frequency shift and arrival angle. Background Art

[0002] Measuring the Doppler frequency shift (hereinafter referred to as DFS) and angle of arrival (hereinafter referred to as AOA) of microwave signals can be used to determine the radial velocity and position of the target, and is widely used in radar, electronic warfare and wireless communication systems. However, traditional electronic solutions are limited in bandwidth, electromagnetic interference and size. Fortunately, microwave photonic technology has the advantages of ultra-wideband, anti-electromagnetic interference, small size and light weight, providing a feasible way to overcome the bottlenecks faced by electronic methods.

[0003] In recent years, photonic schemes for simultaneous measurement of DFS and AOA have been proposed. X.Cao et al. realized the measurement of DFS and AOA based on a dual-channel photon mixer. DFS and AOA are obtained by measuring the frequency and phase difference of the intermediate frequency signals from the two paths. However, it is impossible to measure the angle where the direction of the echo signal is close to the normal direction of the receiving antenna. G. Li et al. used a dual-drive Mach-Zehnder modulator with polarization division multiplexing to construct a dual-channel microwave photon mixer to expand the detection range of AOA. C. Huang et al. proposed a scheme using dual parallel dual-drive Mach-Zehnder modulators and optical filters. The optical filter is used to select the required optical sideband signal, thereby realizing the measurement of DFS and AOA. The use of optical filters limits the measurement bandwidth of the system.

[0004] X. Li et al. used two Mach-Zehnder modulators to split the optical signal into two independent arms. DFS was obtained from the intermediate frequency signal. The AOA information was obtained by analyzing the phase information of the output waveform between the two arms. However, the phase information of the two independent optical signals is easily affected by the external environment, and it is difficult to obtain a stable time domain waveform, which brings challenges to the back-end waveform analysis. Summary of the invention

[0005] The object of the present invention is to provide a photonic device for simultaneously measuring Doppler frequency shift and arrival angle in order to solve one of the above problems.

[0006] To achieve the above-mentioned purpose, some embodiments of the present invention provide a photonic device for simultaneously measuring Doppler frequency shift and arrival angle, which includes a semiconductor laser, a first dual parallel Mach-Zehnder modulator, a second dual parallel Mach-Zehnder modulator, a first electrical coupler, a second electrical coupler, a 90° electrical coupler, an erbium-doped fiber amplifier, a photodetector and a signal analysis unit; the output end of the semiconductor laser is connected to the optical input port of the first dual parallel Mach-Zehnder modulator, the semiconductor laser is configured to generate a continuous first optical carrier, and the first optical carrier enters the first dual parallel Mach-Zehnder modulator; the transmission signal is divided into two paths through the first electrical coupler, and one path is fed to The transmitting antenna has one path, and the other path is input to the second electrical coupler; the transmitting signal and the reference signal are combined by the second electrical coupler and then enter the 90° electrical coupler, wherein the transmitting signal and the reference signal are both single-frequency microwave signals, and the frequency of the transmitting signal is higher than the frequency of the reference signal; the two signals output from the 90° electrical coupler are respectively loaded into the two RF ports of the first dual parallel Mach-Zehnder modulator, and the first dual parallel Mach-Zehnder modulator is configured to suppress single sideband modulation of the first optical carrier by the transmitting signal and the reference signal to obtain two positive first-order sideband signals; the output end of the first dual parallel Mach-Zehnder modulator is connected to the erbium-doped optical fiber The input end of the amplifier is connected to the input end of the amplifier, so that the two positive first-order sideband signals generated by the first dual parallel Mach Zehnder modulator enter the erbium-doped fiber amplifier for power amplification; the output end of the erbium-doped fiber amplifier is connected to the optical input port of the second dual parallel Mach Zehnder modulator, so that the two positive first-order sideband signals after power amplification enter the second dual parallel Mach Zehnder modulator as the second optical carrier and the third optical carrier respectively; after the first receiving antenna and the second receiving antenna respectively receive the first target echo and the second target echo of the transmission signal from the transmitting antenna, they are respectively loaded into the two radio frequency ports of the second dual parallel Mach Zehnder modulator for respectively modulating The second optical carrier and the third optical carrier are controlled, the two sub-modulators of the second dual parallel Mach-Zehnder modulator operate at an orthogonal point, and the main modulator operates at a maximum point; the optical output end of the second dual parallel Mach-Zehnder modulator is connected to a photodetector, so that the optical signal output by the second dual parallel Mach-Zehnder modulator enters the photodetector for beat frequency, and generates a down-converted electrical signal; the output end of the photodetector is connected to the signal analysis unit, and the signal analysis unit is configured to obtain the size and direction of the Doppler frequency shift by analyzing the frequency of the down-converted electrical signal and the frequency of the reference signal; and the arrival angle is estimated by monitoring the power of the down-converted electrical signal.

[0007] In some embodiments, the signal analysis unit is an electric spectrum analyzer, a vector signal analyzer, an oscilloscope with FFT, or a network analyzer.

[0008] In some embodiments, the photodetector is a photodiode.

[0009] In some embodiments, the first dual parallel Mach-Zehnder modulator and the second dual parallel Mach-Zehnder modulator respectively include a Y-type optical beam splitter, a Y-type optical coupler, two sub-modulators and a main modulator; wherein the two sub-modulators are intensity modulators and the main modulator is an optical phase shifter.

[0010] In some embodiments, the frequency of the reference signal can be much lower than the frequency of the transmission signal, thereby reducing the performance requirements of subsequent devices. For example, the frequency of the reference signal is 0 to 2 GHz, such as 1 GHz and below, while the frequency of the transmission signal is 4 to 20 GHz. The photodetector is a photodiode, and the bandwidth of the photodiode is slightly larger than the frequency range of the reference signal, such as 0 to 2.2 GHz, and the frequency response is, for example, 0.8 A / W.

[0011] In some embodiments, the signal analysis unit is configured to calculate the normalized power of the down-converted electrical signal, obtain the Doppler frequency shift and the phase difference between the first echo signal and the second echo signal from the normalized power and the down-converted electrical signal generated by the photodetector, and then calculate the arrival angle .

[0012] Some other embodiments of the present application propose a method for simultaneously measuring Doppler frequency shift and angle of arrival, which is implemented based on any one of the above-mentioned photonic devices for simultaneously measuring Doppler frequency shift and angle of arrival, and the method includes the steps of: making a semiconductor laser generate a continuous optical carrier and entering the first dual parallel Mach-Zehnder modulator; the transmission signal and the reference signal are combined and then enter a 90° electrical coupler; the two signals output by the 90° electrical coupler are loaded into two RF ports of the first dual parallel Mach-Zehnder modulator; the first dual parallel Mach-Zehnder modulator uses carrier suppressed single sideband modulation to generate two positive first-order sideband signals, and the two positive first-order sideband signals are sent to an erbium-doped fiber amplifier for power amplification; the two positive first-order sideband signals after amplification as two optical carriers entering the second dual parallel Mach-Zehnder modulator; the first target echo and the second target echo received by the first receiving antenna and the second receiving antenna are respectively loaded into the second dual parallel Mach-Zehnder modulator for modulating the two optical carriers, wherein the two sub-modulators of the second dual parallel Mach-Zehnder modulator operate at orthogonal points, and the main modulator operates at a maximum point; the optical signal output by the second dual parallel Mach-Zehnder modulator is sent to a photodetector for frequency beat to generate a down-converted electrical signal; the frequency of the down-converted electrical signal and the frequency of the reference signal are analyzed using the electrical spectrum analyzer to obtain the size and direction of the Doppler frequency shift; and the arrival angle is estimated by monitoring the power of the down-converted electrical signal.

[0013] The scheme in the embodiment of the present application can derive the size and direction of DFS by comparing the low-frequency down-converted electrical signal output by the photodiode (also referred to as PD) and the reference signal frequency. The role of the reference signal is to determine the direction of DFS and realize the down-conversion of the echo signal. The target AOA information can be obtained by monitoring the power of the down-converted electrical signal. Compared with the dual-channel measurement scheme using two PDs, the single-channel measurement scheme proposed in the present application only requires a single photodiode to complete the measurement of DFS and AOA, and the structure is simpler. In addition, the present application does not require optical filters and polarization control devices, thereby improving the measurement accuracy and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 4 is a schematic diagram of a photonic device for simultaneously measuring Doppler frequency shift and arrival angle according to an embodiment of the present invention.

[0015] Figure 2 is a spectrum diagram of the output signal of the device, where the Doppler frequency shift DFS is +1 MHz.

[0016] Figure 3 is a spectrum diagram of the output signal of the device, wherein the Doppler frequency shift DFS is -1 MHz.

[0017] Figure 4 Schematic diagram of DFS and its error measured by the device of the present application.

[0018] Figure 5 Schematic diagram of the AOA and its error measured by the device of the present application. DETAILED DESCRIPTION

[0019] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clearly, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0020] like Figure 1 As shown, a photonic device for simultaneously measuring Doppler frequency shift and arrival angle proposed in an embodiment of the present invention includes a semiconductor laser 1, a first dual parallel Mach-Zehnder modulator 2, a second dual parallel Mach-Zehnder modulator 7, a first electric coupler 3, a second electric coupler 4, a 90° electric coupler 5, an erbium-doped fiber amplifier 6, a photodiode 8, and an electric spectrum analyzer 9.

[0021] Each of the dual parallel Mach-Zehnder modulators includes a Y-type optical beam splitter, a Y-type optical coupler, two sub-modulators and a main modulator; the two sub-modulators are intensity modulators, and the main modulator is an optical phase shifter. The first parallel Mach-Zehnder modulator 2 and the second parallel Mach-Zehnder modulator 7 each have an optical input port, two radio frequency input ports, an optical output port and three DC bias ports.

[0022] The output end of the semiconductor laser 1 is connected to the optical input port 21 of the first dual parallel Mach-Zehnder modulator 2; the transmission signal TS is divided into two paths through the first electrical coupler 3, one path is fed to the transmission antenna AT, and the other path is input to the input port of the second electrical coupler 4; the transmission signal TS and the reference signal RS are combined by the second electrical coupler 4 and enter the input end of the 90° electrical coupler 5; the two signals output from the 90° electrical coupler 5 are respectively loaded into the two RF input ports of the first dual parallel Mach-Zehnder modulator 2; the optical output port 21 of the first dual parallel Mach-Zehnder modulator 2 2 is connected to the input end 61 of the erbium-doped fiber amplifier 6; the output end 62 of the erbium-doped fiber amplifier 6 is connected to the optical input port 71 of the second dual-parallel Mach-Zehnder modulator 7; the first target echo ES1 received by the first receiving antenna AR1 and the second target echo ES2 received by the second receiving antenna AR2 at a distance d from the first receiving antenna AR1 are respectively loaded into the two RF input ports of the second dual-parallel Mach-Zehnder modulator 7; the optical output port 72 of the second dual-parallel Mach-Zehnder modulator 7 is connected to the photodiode 8, and the output end of the photodiode 8 is connected to the electrical spectrum analyzer 9.

[0023] After the transmission signal TS and the reference signal RS are combined at the 90° electrical coupler 5, they enter the first dual parallel Mach-Zehnder modulator 2. The first dual parallel Mach-Zehnder modulator 2 operates in the optical carrier suppressed single sideband modulation mode. The transmission signal TS and the reference signal RS modulate the first optical carrier to generate two positive first (+1) order sideband signals. The two positive first order sideband signals are power amplified by the erbium-doped fiber amplifier 6, that is, after power compensation, they enter the second dual parallel Mach-Zehnder modulator 7, and are modulated by the first echo signal ES1 and the second echo signal ES2 in the second dual parallel Mach-Zehnder modulator 7. The two sub-modulators of the second dual parallel Mach-Zehnder modulator 7 are biased at the orthogonal point, and the main modulator thereof is biased at the maximum point. The modulated optical field signal output by the second dual parallel Mach-Zehnder modulator 7 enters the photodiode 8 for photoelectric conversion to generate a down-converted electrical signal. The electrical spectrum analyzer 9 can obtain the size and direction of the Doppler frequency shift (DFS) by comparing the frequency of the down-converted electrical signal with the reference signal RS. By monitoring the power of the down-converted electrical signal, the angle of arrival (AOA) information of the target can be obtained.

[0024] The frequency of the reference signal in the present application can be much lower than the frequency of the transmission signal, thereby reducing the performance requirements of subsequent devices. For example, the frequency of the reference signal is 0~2GHz, for example, 1GHz and below, and the frequency of the transmission signal is 4~20GHz. The bandwidth of the photodiode is slightly larger than the frequency range of the reference signal, for example, 0~2.2GHz, and the frequency response is, for example, 0.8A / W. In addition to the photodiode 8, other devices can also be selected as photodetectors.

[0025] The principle of the photon device for simultaneously measuring Doppler frequency shift and arrival angle of the present invention is as follows: The transmission signal TS, the reference signal RS, the first echo signal ES1 and the second echo signal ES2 can be expressed as: (1) in V t is the amplitude of the transmit signal TS, f t is the frequency of the transmitted signal TS, V r is the amplitude of the reference signal RS, f r is the frequency of the reference signal RS, V e is the amplitude of the first echo signal ES1 and the second echo signal ES2, f e is the frequency of the first echo signal ES1 and the second echo signal ES2, φis the phase difference between the first echo signal ES1 and the second echo signal ES2; t represents any moment of the signal on the time axis and is a continuous variable used to describe the instantaneous value of the signal at different time points.

[0026] The first optical carrier CW1 emitted by the semiconductor laser 1 enters the first dual parallel Mach-Zehnder modulator 2; wherein, after the transmission signal TS and the reference signal RS are combined, they are injected into the first dual parallel Mach-Zehnder modulator 2 through the 90° electrical coupler 5, and the output optical field of the first dual parallel Mach-Zehnder modulator 2 It is expressed as: (2) Wherein, E0 is the amplitude of the first optical carrier, f0 is the frequency of the first optical carrier, β t =π V t / 2 V π and β r =π V r / 2 V π are the modulation coefficients of the transmit signal and the reference signal respectively. J n (.)yes n Bessel function of the first kind.

[0027] The two positive first-order sideband x signals generated by the first optical carrier CW1 modulated by the first dual parallel Mach-Zehnder modulator 2 are composed of a gain of G The erbium-doped fiber amplifier 6 performs power compensation and enters the two sub-modulators of the second dual-parallel Mach-Zehnder modulator 7 as the second optical carrier CW2 and the third optical carrier CW3. The second optical carrier CW2 and the third optical carrier CW3 are modulated by the first echo signal ES1 and the second echo signal ES2 respectively. The two sub-modulators and the main modulator of the second dual-parallel Mach-Zehnder modulator 7 work at the orthogonal point and the maximum point respectively, and the second dual-parallel Mach-Zehnder modulator 7 outputs an optical field It is expressed as: (3) in β e =π V e / 2 V πis the modulation coefficient of the echo signal, G is the gain of the erbium-doped fiber amplifier 6.

[0028] The down-converted electrical signal generated by the photodiode 8 is: (4) in, , the Doppler shift is ; R is the photodiode responsivity.

[0029] From formula (4), the normalized power P of the down-converted electrical signal is obtained as (5) Therefore, the Doppler frequency shift and the phase difference between the first echo signal ES1 and the second echo signal ES2 are obtained by formula (4) and (5), and the arrival angle is calculated by combining formula (6): (AOA).

[0030] (6) The electric spectrum analyzer 9 is used as a signal analysis unit to obtain the Doppler frequency shift and the arrival angle. The required Doppler frequency shift and arrival angle can be obtained by configuring the electric spectrum analyzer 9 according to the above principle. It should be understood that in addition to the electric spectrum analyzer 9, a vector signal analyzer, an oscilloscope with fast Fourier transform (FFT) or a network analyzer can also be used as a signal analysis unit to calculate the Doppler frequency shift and arrival angle. .

[0031] In some embodiments, the first dual parallel Mach-Zehnder modulator and the second dual parallel Mach-Zehnder modulator respectively include a Y-type optical beam splitter, a Y-type optical coupler, two sub-modulators and a main modulator; wherein the two sub-modulators are intensity modulators and the main modulator is an optical phase shifter.

[0032] To verify that the present invention can simultaneously measure Doppler frequency shift and angle of arrival, the following is a description of experimental verification.

[0033] In the experiment, the wavelength of the continuous optical carrier output by semiconductor laser 1 is set to 1548.934nm and the power is set to 13dBm. The transmission signal, reference signal, first echo signal ES1 and second echo signal ES2 are generated by the signal source. The transmission signal frequency is set to 18 GHz and the power is 12dBm; the reference signal frequency is set to 1GHz and the power is 10dBm; the first echo signal frequency is set to 18.001GHz and the power is 10 dBm, and the second echo signal frequency is set to 17.999 GHz and the power is 10dBm. An electrical phase shifter is used to adjust the phase difference between the first echo signal ES1 and the second echo signal ES2.

[0034] Figure 2 Figure 1 shows the spectrum measured when the echo signal is set to 18.001 GHz. It can be seen that the down-converted electrical signal is generated at 1.001 GHz, which is greater than the frequency of the reference signal, indicating that the DFS is +1 MHz. Similarly, when the echo signal is changed to 17.999 GHz, as shown in Figure 3 As shown, the down-converted electrical signal is located at 0.999 GHz, which is lower than 1 GHz, indicating that the DFS is -1 MHz and the spurious suppression ratio is still higher than 36 dB.

[0035] The DFS and error measured by the device at different frequencies were further studied. During the measurement, the resolution bandwidth, video bandwidth and span of the ESA 9 were set to 1 Hz, 1 Hz and 80 Hz. Figure 4 As shown, when the reference signal is set to 1 GHz, the measured DFS result is very close to the theoretical value. The DFS error measured by the device of the present invention fluctuates within a small range of ±0.1 Hz.

[0036] Figure 5 The experimental and theoretical results of AOA are shown. It can be seen that the designed device achieves AOA measurement from 0° to 90°. The AOA measurement error of the device proposed in the present invention is within ±1.2°.

[0037] The solution proposed in the embodiment of the present application only requires a photodiode (PD) to complete the measurement of DFS and AOA, reducing the requirement for PD bandwidth. At the same time, no optical filter and polarization control device are required, which improves the measurement stability of the system.

[0038] Some other embodiments of the present application also provide a method for simultaneously measuring Doppler frequency shift and angle of arrival, which is implemented based on the above-mentioned photonic device for simultaneously measuring Doppler frequency shift and angle of arrival, and the method comprises the following steps: allowing the continuous optical carrier generated by the semiconductor laser 1 to enter the first dual parallel Mach-Zehnder modulator 2; the transmission signal and the reference signal enter the 90° electrical coupler 5 after being combined; the two signals output by the 90° electrical coupler 5 are respectively loaded into the two RF ports of the first dual parallel Mach-Zehnder modulator 2; the first dual parallel Mach-Zehnder modulator 2 uses carrier suppressed single sideband modulation to generate two positive first-order sideband signals; the two positive first-order sideband signals are sent to the erbium-doped fiber amplifier 6 for power amplification; The two amplified positive first-order sideband signals are respectively sent to the second dual parallel Mach-Zehnder modulator 7 as two optical carriers; the target echoes received by the two receiving antennas are respectively loaded into the second dual parallel Mach-Zehnder modulator 7 for modulating the two optical carriers; the two sub-modulators of the second dual parallel Mach-Zehnder modulator 7 work at the orthogonal point, and the main modulator works at the maximum point; the optical signal output by the second dual parallel Mach-Zehnder modulator 7 enters the photodiode 8 for beat frequency to generate a down-converted electrical signal; the frequency of the down-converted electrical signal and the frequency of the reference signal are analyzed by the electrical spectrum analyzer 9 to obtain the size and direction of the Doppler frequency shift; the arrival angle is estimated by monitoring the power of the down-converted electrical signal.

[0039] In summary, the present invention proposes a photonic device and method for simultaneously measuring DFS and AOA. In this scheme, only a low-frequency PD of 1 GHz is required to complete the measurement of DFS and AOA, which reduces the requirement for PD bandwidth. At the same time, no optical filter and polarization control device are required, which improves the measurement stability of the system. The designed measurement scheme is expected to be applied to fields such as radar and electronic warfare.

[0040] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and inventive concept of the present invention within the technical scope of the present invention, which should be included in the protection scope of the present invention.

Claims

1. A photon device for simultaneously measuring Doppler shift and angle of arrival, characterized in that: It includes a semiconductor laser, a first double parallel Mach-Zehnder modulator, a second double parallel Mach-Zehnder modulator, a first electric coupler, a second electric coupler, a 90° electric coupler, an erbium-doped fiber amplifier, a photodetector and a signal analysis unit; The output end of the semiconductor laser is connected to the optical input port of the first dual parallel Mach-Zehnder modulator, and the semiconductor laser is configured to generate a continuous first optical carrier, and the first optical carrier enters the first dual parallel Mach-Zehnder modulator; The transmitting signal is divided into two paths through the first electrical coupler, one path is fed to the transmitting antenna, and the other path is input to the second electrical coupler; the transmitting signal and the reference signal are combined through the second electrical coupler and enter the 90° electrical coupler, wherein the transmitting signal and the reference signal are both single-frequency microwave signals, and the frequency of the reference signal is lower than the frequency of the transmitting signal; the two signals output from the 90° electrical coupler are respectively loaded to the two RF ports of the first dual parallel Mach-Zehnder modulator, and the first dual parallel Mach-Zehnder modulator is configured to suppress single sideband modulation of the first optical carrier by the transmitting signal and the reference signal to obtain two positive first-order sideband signals; The output end of the first dual parallel Mach-Zehnder modulator is connected to the input end of the erbium-doped fiber amplifier, and the erbium-doped fiber amplifier is configured to power amplify the two positive first-order sideband signals generated by the first dual parallel Mach-Zehnder modulator; The output end of the erbium-doped fiber amplifier is connected to the optical input port of the second dual-parallel Mach-Zehnder modulator, so that the two positive first-order sideband signals after power amplification enter the second dual-parallel Mach-Zehnder modulator as the second optical carrier and the third optical carrier respectively; The first receiving antenna and the second receiving antenna are configured to receive the first target echo and the second target echo of the transmission signal from the transmitting antenna respectively, and then load them to the two radio frequency ports of the second dual parallel Mach-Zehnder modulator respectively for modulating the second optical carrier and the third optical carrier respectively, wherein the two sub-modulators of the second dual parallel Mach-Zehnder modulator operate at the orthogonal point, and the main modulator operates at the maximum point; The optical output end of the second dual parallel Mach-Zehnder modulator is connected to a photodetector, and the photodetector is configured to perform a beat frequency operation on the optical signal output by the second dual parallel Mach-Zehnder modulator to generate a down-converted electrical signal; The output end of the photodetector is connected to the signal analysis unit, and the signal analysis unit is configured to obtain the magnitude and direction of the Doppler frequency shift by analyzing the frequency of the down-converted electrical signal and the frequency of the reference signal; and estimate the arrival angle by monitoring the power of the down-converted electrical signal.

2. The photon device for simultaneously measuring Doppler shift and angle of arrival according to claim 1, characterized in that: The signal analysis unit is an electric spectrum analyzer, a vector signal analyzer, an oscilloscope with FFT or a network analyzer.

3. The photon device for simultaneously measuring Doppler shift and arrival angle according to claim 1, characterized in that: The photodetector is a photodiode.

4. The photon device for simultaneously measuring Doppler shift and arrival angle according to claim 1, characterized in that: The first dual parallel Mach-Zehnder modulator and the second dual parallel Mach-Zehnder modulator respectively include a Y-type optical beam splitter, a Y-type optical coupler, two sub-modulators and a main modulator; wherein the two sub-modulators are intensity modulators and the main modulator is an optical phase shifter.

5. The photon device for simultaneously measuring Doppler shift and arrival angle according to claim 4, characterized in that: The frequency of the reference signal is 0-2 GHz, and the frequency of the transmission signal is 4-20 GHz.

6. The photon device for simultaneously measuring Doppler frequency shift and arrival angle according to claim 4, characterized in that: The photodetector is a photodiode, and the bandwidth of the photodiode is 0-2.2 GHz.

7. The photon device for simultaneously measuring Doppler frequency shift and arrival angle according to claim 6, characterized in that: The signal analysis unit is configured to The normalized power P of the down-converted electrical signal is calculated, and the Doppler frequency shift and the phase difference between the first echo signal and the second echo signal are obtained from the normalized power P and the down-converted electrical signal generated by the photodiode; wherein the down-converted electrical signal i is expressed as: ； in, , the Doppler shift is ，R is the photodiode responsivity; in, is the output light field of the second dual parallel Mach-Zehnder modulator, expressed as: ; in β e =π V e / 2 V π is the modulation coefficient of the first echo signal and the second echo signal, G is the gain of the erbium-doped fiber amplifier; V π yes The voltage required to cause a phase difference of π; in, is the output light field of the first dual parallel Mach-Zehnder modulator, expressed as ; Wherein, E0 is the amplitude of the first optical carrier, f0 is the frequency of the first optical carrier, β t =π V t / 2 V π and β r =π V r / 2 V π are the modulation coefficients of the transmit signal and the reference signal respectively; J n (.)yes n Bessel function of the first kind; Among them, the transmission signal Number (TS), reference signal (RS), first echo signal (ES1) and second echo signal (ES2) surface Shown as: ； in V t is the amplitude of the transmitted signal (TS), f t is the frequency of the transmitted signal (TS), V r is the amplitude of the reference signal (RS), f r is the frequency of the reference signal (RS), V e is the amplitude of the first echo signal (ES1) and the second echo signal (ES2), f e is the frequency of the first echo signal (ES1) and the second echo signal (ES2), φ is the phase difference between the first echo signal (ES1) and the second echo signal (ES2); t represents any time; According to The angle of arrival is calculated.

8. A photon method for simultaneously measuring Doppler frequency shift and arrival angle, using the photon device for simultaneously measuring Doppler frequency shift and arrival angle according to any one of claims 1 to 7, characterized in that: The method comprises the steps of: The semiconductor laser generates a continuous optical carrier and enters the first dual parallel Mach-Zehnder modulator; the transmission signal and the reference signal are combined and enter the 90° electrical coupler; the two signals output by the 90° electrical coupler are respectively loaded into the two radio frequency ports of the first dual parallel Mach-Zehnder modulator; the first dual parallel Mach-Zehnder modulator uses carrier suppressed single sideband modulation to generate two positive first-order sideband signals, and the two positive first-order sideband signals are sent to the erbium-doped fiber amplifier for power amplification; the two amplified positive first-order sides enter the second dual parallel Mach-Zehnder modulator as two optical carriers; the first receiving antenna The first target echo and the second target echo received by the second receiving antenna are respectively loaded into the second dual parallel Mach-Zehnder modulator for modulating the two optical carriers, wherein the two sub-modulators of the second dual parallel Mach-Zehnder modulator operate at the orthogonal point, and the main modulator operates at the maximum point; the optical signal output by the second dual parallel Mach-Zehnder modulator is sent to the photodetector for beat frequency to generate a down-converted electrical signal; the signal analysis unit is used to analyze the frequency of the down-converted electrical signal and the frequency of the reference signal to obtain the size and direction of the Doppler frequency shift; and the arrival angle is estimated by monitoring the power of the down-converted electrical signal.

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