Optical Carrier Microwave-Based Multipath Distance Measurement System, Method, and Electronic Device

Abstract

The present disclosure provides a multipath distance measurement system, method, and electronic device based on optically carried microwaves, which can be applied to the field of microwave ranging technology. The system includes: an electro-optic modulation unit for modulating a microwave signal and an optical wave signal to obtain an optically carried microwave signal; an interference unit including a plurality of measurement paths and a reference path, the interference unit being configured to cause the optically carried microwave signal to pass through the plurality of measurement paths to obtain measurement signals corresponding to each measurement path, pass through the reference path to obtain a reference signal, and couple the plurality of measurement signals with the reference signal to obtain a coupled microwave signal; a photoelectric detection unit for converting the coupled microwave signal into an electrical signal; a mixing unit for mixing according to the electrical signal and the microwave signal to obtain a mixed microwave signal; and an amplitude processing unit for detecting the amplitude of the electrical signal and the phase of the mixed microwave signal, and determining the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

Description

Technical Field

[0001] The present disclosure relates to the technical field of microwave ranging, and more particularly, to a multi-path distance measurement system, method, and electronic device based on optically carried microwave. Background Art

[0002] Distance information is basic information in aspects such as aviation navigation, engineering surveying, transportation and infrastructure construction, frontier scientific research, and industrial equipment manufacturing. For example, in aviation navigation, in order for an aircraft to land safely, the distance to the landing point is indicated. In transportation and infrastructure construction, in order to ensure the safety and durability of transportation infrastructure, accurate distances of relevant roads need to be provided. Therefore, the measurement of distance is also a key point in related technologies. In order to achieve comprehensive perception from one-dimensional to three-dimensional position and attitude space, it is usually necessary to obtain distance information from multiple paths while ensuring measurement accuracy. However, the multi-path distance measurement systems in related technologies are relatively complex and costly. Summary of the Invention

[0003] In view of this, the present disclosure provides a multi-path distance measurement system, method, and electronic device based on optically carried microwave.

[0004] One aspect of the present disclosure provides a multi-path distance measurement system based on optically carried microwave, including: an electro-optic modulation unit for modulating a microwave signal and an optical wave signal to obtain an optically carried microwave signal, and transmitting the optically carried microwave signal to an interference unit; the interference unit is connected to the electro-optic modulation unit and includes a plurality of measurement paths and a reference path. Each of the plurality of measurement paths represents a distance to be measured. The interference unit is configured to cause the optically carried microwave signal to pass through the plurality of measurement paths to obtain a measurement signal corresponding to each measurement path, pass through the reference path to obtain a reference signal, and couple the plurality of measurement signals with the reference signal to obtain a coupled microwave signal; a photoelectric detection unit is connected to the interference unit for converting the coupled microwave signal into an electrical signal; a mixing unit is connected to the electro-optic modulation unit and the photoelectric detection unit for mixing according to the electrical signal and the microwave signal to obtain a mixed microwave signal; an amplitude processing unit is connected to the photoelectric detection unit and the mixing unit for detecting the amplitude of the electrical signal and the phase of the mixed microwave signal, and determining the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

[0005] According to an embodiment of the present disclosure, the above reference path includes an optical fiber, each of the above measurement paths includes a circulator and a collimator, the above optical fiber connects the electro-optic modulation unit and the photoelectric detection unit, and the circulator in each of the above measurement paths connects the electro-optic modulation unit and the photoelectric detection unit; in the above reference path, the optical microwave signal passes through the above optical fiber to obtain the above reference signal; in each of the above measurement paths, the optical microwave signal passes through the above circulator to reach the above collimator, reaches the measurement target corresponding to the measurement path through the above collimator, and is reflected back to the above collimator through the measurement target corresponding to the measurement path, and the above measurement signal corresponding to the measurement path is obtained through the above circulator, wherein the distance between the above collimator and the above measurement target is the above distance to be measured.

[0006] According to an embodiment of the present disclosure, the above amplitude processing unit includes an amplitude detection sub-unit and a data processing sub-unit; the above amplitude detection sub-unit is connected to the above photoelectric detection unit and is used to detect the amplitude of the above electrical signal; the above data processing sub-unit is connected to the above amplitude detection sub-unit and the above mixing unit and is used to detect the phase of the above mixed microwave signal, and determine the above distance to be measured corresponding to each of the above measurement paths according to the amplitude of the above electrical signal and the phase of the above mixed microwave signal.

[0007] According to an embodiment of the present disclosure, the above amplitude detection sub-unit is used to obtain the amplitude of the above electrical signal by performing integration and square root operations on the square of the above electrical signal.

[0008] According to an embodiment of the present disclosure, the above amplitude detection sub-unit realizes the integration and square root operations on the square of the above electrical signal based on an integration filter capacitor to obtain the amplitude of the above electrical signal.

[0009] According to an embodiment of the present disclosure, the above data processing sub-unit includes a data acquisition card and a lower computer; the above data acquisition card is connected to the above amplitude detection sub-unit and the above mixing unit and is used to perform frequency scanning on the above electrical signal to obtain the amplitude spectrum of the above electrical signal and detect the phase of the above mixed microwave signal; the above lower computer is connected to the above data acquisition card and is used to determine the above distance to be measured corresponding to each of the above measurement paths according to the period of the above amplitude spectrum and the phase of the above mixed microwave signal.

[0010] According to an embodiment of the present disclosure, the above electro-optic modulation unit includes a broadband light source, a microwave signal source and an electro-optic modulator; the above broadband light source is connected to the above electro-optic modulator and is used to generate the above optical wave signal; the above microwave signal source is connected to the above electro-optic modulator and the above mixing unit and is used to generate the above microwave signal; the above electro-optic modulator is used to modulate the microwave signal and the optical wave signal to obtain the above optical microwave signal.

[0011] According to an embodiment of the present disclosure, the interference unit further includes a coupler, and the coupler is connected to the plurality of measurement paths and the reference path, and is configured to couple the plurality of measurement signals and the reference signal to obtain the coupled microwave signal.

[0012] Another aspect of the present disclosure provides a multi-path distance measurement method based on optically carried microwave, including: modulating a microwave signal and an optical wave signal through an electro-optic modulation unit to obtain an optically carried microwave signal, and transmitting the optically carried microwave signal to an interference unit, where the interference unit is connected to the electro-optic modulation unit, and the interference unit includes a plurality of measurement paths and a reference path, and each of the plurality of measurement paths represents a distance to be measured; enabling the optically carried microwave signal to pass through the plurality of measurement paths through the interference unit to obtain a measurement signal corresponding to each measurement path, obtaining a reference signal through the reference path, and coupling the plurality of measurement signals and the reference signal to obtain a coupled microwave signal; converting the coupled microwave signal into an electrical signal through a photoelectric detection unit; performing mixing on the electrical signal and the microwave signal through a mixing unit to obtain a mixed microwave signal; detecting the amplitude of the electrical signal and the phase of the mixed microwave signal through an amplitude processing unit, and determining the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

[0013] Another aspect of the present disclosure provides an electronic device, including: one or more processors; a memory for storing one or more programs, where when the one or more programs are executed by the one or more processors, the one or more processors implement the method as described above.

[0014] According to an embodiment of the present disclosure, the multi-path distance measurement system based on optically carried microwave uses an electro-optic modulation unit to obtain an optically carried microwave signal, designs a plurality of measurement paths and a reference path in the interference unit, the plurality of measurement paths correspond to a plurality of distances to be measured, and the plurality of measurement paths share the same electro-optic modulation unit and photoelectric detection unit, which simplifies the system structure. The reference signal and the measurement signal are interfered through the photoelectric detection unit, the coupled microwave signal is converted into an electrical signal, the electrical signal and the microwave signal are mixed through the mixing unit to obtain a mixed microwave signal, and the synchronous distance calculation of multiple paths is realized through the analysis of the amplitude of the electrical signal and the phase of the mixed microwave signal. At the same time, the system does not depend on a high-performance light source, has a simple structure, and reduces the construction cost of the system. Description of the Drawings

[0015] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0016] Figure 1 Schematically shows a schematic diagram of a multi-path distance measurement system based on optical carrier microwave according to an embodiment of the present disclosure;

[0017] Figure 2 Schematically shows a delay image of the optical path information of each of multiple measurement paths according to an embodiment of the present disclosure;

[0018] Figure 3 Schematically shows a schematic diagram of a multi-path distance measurement system based on optical carrier microwave according to another embodiment of the present disclosure;

[0019] Figure 4 Schematically shows a flowchart of a multi-path distance measurement method based on optical carrier microwave according to an embodiment of the present disclosure; and

[0020] Figure 5 Schematically shows a block diagram of an electronic device suitable for implementing a multi-path distance measurement method based on optical carrier microwave according to an embodiment of the present disclosure. Detailed implementation manners

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0022] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0023] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0024] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0025] In the related art, laser ranging technology and instruments have poor scalability in multipath distance measurement. Increasing the number of measurement channels means that additional hardware and software similar to the original system are required, which not only increases the construction cost and complexity of the system, but also reduces the reliability of the multi-channel measurement system. In addition, a method of using multiple distance measurement systems to record the distance information of each channel respectively is adopted to complete multipath distance measurement. However, the synchronization of this solution is relatively poor, which may cause the failure of the mathematical model constructed based on multiple lengths and increase the difficulty of subsequent geometric coefficient decoupling.

[0026] The ranging technology based on optical carrier microwave swept-frequency interference is a new ranging technology that combines photon technology and microwave technology, and can be effectively applied in a multipath distance measurement system.

[0027] In view of this, an embodiment of the present disclosure provides a multipath distance measurement system based on optical carrier microwave, including: an electro-optic modulation unit for modulating a microwave signal and an optical wave signal to obtain an optical carrier microwave signal, and transmitting the optical carrier microwave signal to an interference unit; an interference unit connected to the electro-optic modulation unit, including a plurality of measurement paths and a reference path, each measurement path in the plurality of measurement paths represents a distance to be measured, the interference unit is used to make the optical carrier microwave signal pass through the plurality of measurement paths to obtain measurement signals corresponding to each measurement path, pass through the reference path to obtain a reference signal, and couple the plurality of measurement signals with the reference signal to obtain a coupled microwave signal; a photoelectric detection unit connected to the interference unit for converting the coupled microwave signal into an electrical signal; a mixing unit connected to the electro-optic modulation unit and the photoelectric detection unit for mixing according to the electrical signal and the microwave signal to obtain a mixed microwave signal; an amplitude processing unit connected to the photoelectric detection unit and the mixing unit for detecting the amplitude of the electrical signal and the phase of the mixed microwave signal, and determining the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

[0028] According to the embodiment of the present disclosure, the ranging technology based on optical carrier microwave swept-frequency interference uses the electro-optic modulation unit to obtain an optical carrier microwave signal, designs a plurality of measurement paths and a reference path in the interference unit, the plurality of measurement paths correspond to a plurality of distances to be measured, and the plurality of measurement paths share the same electro-optic modulation unit and photoelectric detection unit, which simplifies the system structure. The reference signal and the measurement signal are interfered by the photoelectric detection unit, and the coupled microwave signal is converted into an electrical signal. The electrical signal and the microwave signal are mixed by the mixing unit to obtain a mixed microwave signal. By analyzing the amplitude of the electrical signal and the phase of the mixed microwave signal, synchronous distance calculation of multiple paths is realized. At the same time, the system does not depend on a high-performance light source, has a simple structure, and reduces the construction cost of the system.

[0029] Figure 1Schematically shows a schematic diagram of a multi - path distance measurement system based on optically - carried microwave according to an embodiment of the present disclosure.

[0030] As Figure 1 shown, the multi - path distance measurement system 100 based on optically - carried microwave includes an electro - optic modulation unit 110, an interference unit 120, a photoelectric detection unit 130, a mixing unit 140, and an amplitude processing unit 150.

[0031] According to an embodiment of the present disclosure, the electro - optic modulation unit 110 modulates a microwave signal and an optical wave signal to obtain an optically - carried microwave signal. The electro - optic modulation unit 110 is connected to the interference unit 120, and the connection method can be fiber - optic connection to transmit the optically - carried microwave signal to the interference unit 120.

[0032] According to an embodiment of the present disclosure, the electro - optic modulation unit 110 loads the microwave signal onto the optical wave signal for intensity modulation to form an optically - carried microwave signal:

[0033] (1)

[0034] Wherein, is the amplitude of the optical signal, is the frequency of the optical signal, is the frequency of the microwave signal, is the initial optical - domain phase introduced by the electro - optic modulation unit, j is the imaginary unit, and t is time.

[0035] According to an embodiment of the present disclosure, the interference unit 120 includes a plurality of measurement paths and a reference path. Each of the plurality of measurement paths represents a distance to be measured. The interference unit 120 is used to make the optically - carried microwave signal pass through the plurality of measurement paths to obtain measurement signals corresponding to each measurement path, pass through the reference path to obtain a reference signal, and couple the plurality of measurement signals with the reference signal to obtain a coupled microwave signal.

[0036] According to an embodiment of the present disclosure, each of the plurality of measurement paths includes a spatial optical path. Since the measurement path and the reference path are different paths, after the optically - carried microwave signal passes through the measurement path and the reference path, the optical path difference between the obtained measurement signal and the reference signal is different.

[0037] According to an embodiment of the present disclosure, the photoelectric detection unit 130 is connected to the interference unit, and the connection method can be fiber - optic connection, and is used to convert the coupled microwave signal into an electrical signal, that is, an optically - carried microwave interference signal.

[0038] According to an embodiment of the present disclosure, an optical microwave signal is transmitted to a plurality of measurement paths. After passing through the spatial optical paths of each of the plurality of measurement paths, it returns to the interference unit 120, is coupled and superimposed with the reference signal transmitted through the reference path to form a coupled microwave signal. The coupled microwave signal enters the optoelectronic detection unit 130 to complete interference and is converted into an electrical signal.

[0039] According to an embodiment of the present disclosure, the coupled microwave signal is converted into an electrical signal, that is, an optical microwave interference signal. Since the optical path difference is much larger than the coherence length of the optical wave signal, the optical interference term is approximately zero. Therefore, the signal detected by the optoelectronic detection unit 130 is the superposition of multiple microwave signals with the same frequency but different phases. The coupled microwave signal can be expressed as:

[0040] (2)

[0041] Wherein, , ...... are the amplitudes of the signals of the 1st, 2nd,...... nth paths to which the photodetector responds respectively, is the microwave signal frequency, , ...... are the distances to be measured of the signals in the 1st, 2nd,...... nth measurement paths respectively, is the length of the electrical common path. Among them, the length of the electrical common path can be the part that the optical microwave signal passes through in common in the measurement path and the reference path.

[0042] According to an embodiment of the present disclosure, the mixing unit 140 is electrically connected to the electro-optic modulation unit 110 and the mixing unit 140 is electrically connected to the optoelectronic detection unit 130. The mixing unit 140 is used to mix according to the electrical signal and the microwave signal to obtain a mixed microwave signal.

[0043] According to an embodiment of the present disclosure, the microwave signal is divided into two paths. One path is modulated with the optical wave signal in the electro-optic modulation unit; the other path is used as the local oscillator signal in the mixing unit 140.

[0044] According to an embodiment of the present disclosure, a part of the electrical signal output by the optoelectronic detection unit 130 enters the mixing unit 140 and is mixed with the microwave signal as the local oscillator signal to obtain a mixed microwave signal.

[0045] According to an embodiment of the present disclosure, the doubled-frequency signal after mixing is filtered due to the limitation of the output frequency bandwidth of the mixing unit 140. Therefore, the mixed microwave signal output at each frequency is a single DC signal and can be expressed as:

[0046] (3)

[0047] Wherein, is the interference amplitude spectrum, is the interference phase spectrum.

[0048] According to an embodiment of the present disclosure, the amplitude processing unit 150 is electrically connected to the optoelectronic detection unit 130 and is configured to detect the amplitude of the electrical signal.

[0049] According to an embodiment of the present disclosure, another part of the electrical signal output by the optoelectronic detection unit 130 enters the amplitude processing unit 150. The expression of the electrical signal entering the amplitude processing unit 150 is as shown in formula (2), and the amplitude of the detected electrical signal can be expressed as:

[0050] (4)

[0051] where, is the amplitude of the output signal of the photodetector, is the proportionality coefficient, which is only related to the resistance ratio in the amplitude detection device, is the proportionality coefficient and the product of the remaining constant terms in the integrated formula.

[0052] According to an embodiment of the present disclosure, during the measurement process, the microwave signal frequency scans at high speed. When the target is fixed, the amplitude detection signal changes periodically with the change of the microwave signal frequency .

[0053] According to an embodiment of the present disclosure, the amplitude processing unit 150 is electrically connected to the mixing unit 140 and is configured to detect the phase of the mixed microwave signal.

[0054] According to an embodiment of the present disclosure, the interference phase of the mixed microwave signal includes information about the distance to be measured.

[0055] According to an embodiment of the present disclosure, the amplitude processing unit 150 can determine the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

[0056] According to an embodiment of the present disclosure, the amplitude processing unit 150 can obtain the amplitude spectrum of the electrical signal and the phase spectrum of the mixed microwave signal. Based on the amplitude spectrum and the phase spectrum, the microwave signal in the coupled microwave signal can be restored. The distance to be measured corresponding to each measurement path is determined according to the microwave signal in the coupled microwave signal.

[0057] According to an embodiment of the present disclosure, the optical wave signal serves as a transmission carrier. With its characteristics of easy collimation and anti-interference, it provides a high spatial resolution and high-quality transmission signals; the microwave signal serves as the information main body. Due to its more mature processing technology, the electro-optic modulation unit, interference unit, photoelectric detection unit, and amplitude processing unit have the potential for integration and miniaturization. Therefore, by combining the optical wave signal and the microwave signal, the range of distance measurement is increased, and at the same time, the accuracy of distance measurement is improved.

[0058] According to an embodiment of the present disclosure, an optical carrier microwave signal is obtained by using an electro-optic modulation unit. Multiple measurement paths and a reference path are designed in the interference unit. The multiple measurement paths correspond to multiple distances to be measured. The multiple measurement paths share the same electro-optic modulation unit and photoelectric detection unit, and there is no need to set an electro-optic modulation unit and a photoelectric detection unit for each measurement path, which simplifies the system structure. The reference signal and the measurement signal are interfered by the photoelectric detection unit to convert the coupled microwave signal into an electrical signal. The electrical signal and the microwave signal are mixed by the mixing unit to obtain a mixed microwave signal. While the microwave signal is swept, the amplitude of the electrical signal and the phase of the mixed microwave signal are detected by using the amplitude processing unit. The distances to be measured of multiple paths are synchronously solved by using the amplitude spectrum of the electrical signal and the phase spectrum of the mixed microwave signal.

[0059] According to an embodiment of the present disclosure, the distance to be measured corresponding to each measurement path is determined according to the microwave signal in the coupled microwave signal, which may be to perform an inverse Fourier transform on this microwave signal to obtain a delay image showing the respective optical path information in multiple measurement paths, and the distance to be measured corresponding to each measurement path is determined according to the delay image.

[0060] Figure 2 Schematically shows a delay image of the respective optical path information in multiple measurement paths according to an embodiment of the present disclosure.

[0061] According to an embodiment of the present disclosure, the delay image is displayed in a pulse pattern, and the number of pulses is equal to the number of transmission channels. The transmission channels include measurement paths and reference paths.

[0062] As Figure 2 shown, when there are two measurement paths in the distance measurement system, the first pulse on the left represents the microwave signal of the reference signal in the reference path, and the two pulses on the right represent the microwave signals of the measurement signals of the two measurement paths. The amplitude of the pulse is proportional to the echo energy. The echo energy refers to the energy of the optical carrier microwave signal after passing through the spatial optical paths of multiple measurement paths and returning to the interference unit. At this time, the resolution of the delay image cannot meet the requirements of ranging accuracy.

[0063] According to an embodiment of the present disclosure, microwave signals corresponding to each reference path are separated based on the optical path difference between different measurement paths, and the amplitude spectrum of the microwave signal of each reference path is reconstructed. After discrete Fourier transform, the spectrum of the reconstructed single-channel signal is obtained, and the single-channel signal can be expressed as:

[0064] (5)

[0065] As shown in formula (5), the optical path difference is inversely proportional to the period of the amplitude spectrum, and the information of the distance to be measured can be extracted from the periodic signal of the separated signal. The distance to be measured is expressed as:

[0066] (6)

[0067] Wherein, FSR represents the period of the periodic signal, that is, the free spectral range. Figure 3 Schematically shows a schematic diagram of a multi-path distance measurement system based on optically carried microwave according to another embodiment of the present disclosure.

[0068] As Figure 3 shown, the distance measurement system 300 includes an electro-optic modulation unit, an interference unit, a photoelectric detection unit 330, a mixing unit 340, and an amplitude processing unit. The electro-optic modulation unit is connected to the interference unit through an optical fiber, the interference unit is connected to the photoelectric detection unit 330 through an optical fiber, the electro-optic modulation unit is electrically connected to the mixing unit 340, the photoelectric detection unit 330 is electrically connected to the mixing unit 340, the photoelectric detection unit 330 is electrically connected to the amplitude processing unit, and the mixing unit 340 is electrically connected to the amplitude processing unit.

[0069] As Figure 3 shown, the electro-optic modulation unit includes a broadband light source 311, a microwave signal source 312, and an electro-optic modulator 313. The broadband light source 311 is fiber-connected to the electro-optic modulator 313, and the microwave signal source 312 is electrically connected to the electro-optic modulator 313.

[0070] As Figure 3 shown, the interference unit includes a separation coupler 321, a measurement path, a reference path, and a coupler 325. The reference path includes an optical fiber 322, and the measurement path includes a plurality of circulators 323 and a plurality of collimators 324. Inside the interference unit, all are connected through optical fibers.

[0071] As Figure 3 shown, the amplitude processing unit includes an amplitude detection sub-unit 351 and a data processing sub-unit. The data processing sub-unit includes a data acquisition card 352 and a lower computer 253. Inside the amplitude processing unit, all are electrically connected.

[0072] According to an embodiment of the present disclosure, the optical fiber 322 connects the electro-optic modulation unit and the photoelectric detection unit 330, and the circulator 323 in each measurement path connects the electro-optic modulation unit and the photoelectric detection unit 330.

[0073] According to an embodiment of the present disclosure, in the reference path, the optical microwave signal passes through the optical fiber 322 to obtain a reference signal.

[0074] According to an embodiment of the present disclosure, in each measurement path, the optical microwave signal passes through the circulator 323 to reach the collimator 324, passes through the collimator 324 to reach the measurement target 360 corresponding to the measurement path, and is reflected back to the collimator 324 through the measurement target 360 corresponding to the measurement path, and the measurement signal corresponding to the measurement path is obtained through the circulator 323, wherein the distance between the collimator 324 and the measurement target 360 is the distance to be measured.

[0075] According to an embodiment of the present disclosure, the multiple measurement paths further correspond to multiple spatial optical paths. The optical microwave signal enters the spatial optical path through the collimator and is reflected back to the collimator at the measurement target. By adjusting the spatial optical path, it is ensured that the optical microwave signal can be reflected back to the collimator at the measurement target.

[0076] According to an embodiment of the present disclosure, the optical microwave signal is reflected by the measurement target in the measurement path to form a measurement signal, and is coupled and superimposed with the reference signal at the coupler. The reference signal and the measurement signal have different optical paths, and after passing through the photoelectric detection unit, they are converted into two microwave signals with different phases and interfere with each other to generate a coupled microwave signal, which is the interference signal of the optical microwave signal. During the microwave signal sweep process, the distance to be measured can be calculated according to the interference spectrum diagram.

[0077] According to an embodiment of the present disclosure, the amplitude detection sub-unit 351 is electrically connected to the photoelectric detection unit 330 and is used to detect the amplitude of the electrical signal.

[0078] According to an embodiment of the present disclosure, the data processing sub-unit is electrically connected to the amplitude detection sub-unit 351 and the mixing unit 340, and is used to detect the phase of the mixed microwave signal, and determine the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

[0079] According to an embodiment of the present disclosure, the amplitude detection sub-unit 351 is used to obtain the amplitude of the electrical signal by performing integration and square root operations on the square of the electrical signal.

[0080] According to an embodiment of the present disclosure, the amplitude detection sub-unit 351 realizes the integration and square root operations on the square of the electrical signal based on an integrating filter capacitor to obtain the amplitude of the electrical signal.

[0081] According to an embodiment of the present disclosure, the amplitude of the output signal of the amplitude detection sub-unit is a DC signal, which greatly reduces the requirement for the sampling frequency. The amplitude detection sub-unit performs multi-stage filtering based on the integration filter capacitor to perform auxiliary conditioning on the electrical signal.

[0082] According to an embodiment of the present disclosure, the data acquisition card 352 is connected to the amplitude detection sub-unit 351 and the frequency mixing unit 340, and is used to perform frequency scanning on the electrical signal to obtain the amplitude spectrum of the electrical signal and detect the phase of the frequency mixed microwave signal.

[0083] According to an embodiment of the present disclosure, the lower computer 353 is connected to the data acquisition card 352, and is used to determine the distance to be measured corresponding to each measurement path according to the period of the amplitude spectrum and the phase of the frequency mixed microwave signal.

[0084] According to an embodiment of the present disclosure, the lower computer 353 can also be used to store data.

[0085] According to an embodiment of the present disclosure, the distance to be measured is reflected in the interference phase of the frequency mixed microwave signal. After further extracting the interference phase, the distance information to be measured can be calculated from it. By using the Hilbert transform to generate an orthogonal spectrum system, high-precision phase information can be obtained.

[0086] According to an embodiment of the present disclosure, by using microwave signal frequency scanning, the amplitude spectrum of the coupled microwave signal and the phase spectrum of the frequency mixed microwave signal can be obtained, and the distance information to be measured is extracted according to the amplitude spectrum and the phase spectrum. The distance measurement system of the present disclosure has a low requirement for the sampling frequency of the data acquisition card and does not have a strict requirement for the sampling bandwidth.

[0087] According to an embodiment of the present disclosure, the broadband light source 311 is connected to the electro-optic modulator 313 and is used to generate an optical wave signal. The wavelength range of the optical wave signal generated by the broadband light source 311 is relatively large, and its coherence length is much smaller than the interference length of the distance measurement system.

[0088] According to an embodiment of the present disclosure, the wavelength range of the optical wave signal includes 1530 nm - 1565 nm. For example, the wavelength range of the optical wave signal is 1530 nm - 1565 nm, its coherence length is about 46 μm, the interference length range of the measurement system includes 0.5 m - 200 m, and the interference length of the distance measurement system is more than 1000 times greater than the coherence length of the optical wave signal.

[0089] According to an embodiment of the present disclosure, the microwave signal source 312 is connected to the electro-optic modulator 313 and the frequency mixing unit 340 and is used to generate a microwave signal.

[0090] According to an embodiment of the present disclosure, the microwave signal is input into the interference unit as a frequency sweep signal to obtain an interference spectrogram, and then the optical path difference between the measurement path and the reference path is calculated.

[0091] According to an embodiment of the present disclosure, an electro-optic modulator 313 is configured to modulate a microwave signal and an optical wave signal to obtain an optical carrier microwave signal.

[0092] According to an embodiment of the present disclosure, using a broadband light source can effectively avoid the influence of light interference on measurement; the microwave signal source can perform rapid frequency scanning in a short time; the bias voltage control of the electro-optic modulator enables its output to maintain stable power during the frequency sweep.

[0093] According to an embodiment of the present disclosure, the frequency sweep rate range includes 1 GHz / s - 10 GHz / s. For example, the frequency sweep rate is 1 GHz / s, the frequency sweep rate is 2 GHz / s, and the frequency sweep rate is 10 GHz / s.

[0094] According to an embodiment of the present disclosure, the interference unit further includes a coupler 325. The coupler 325 is connected to multiple measurement paths and a reference path, and is configured to couple multiple measurement signals and a reference signal to obtain a coupled microwave signal.

[0095] According to an embodiment of the present disclosure, the interference unit further includes a splitting coupler 321, which is configured to split the optical carrier microwave signal, so that the optical carrier microwave signal enters multiple measurement paths and a reference path.

[0096] Figure 4 A flowchart of a multi-path distance measurement method based on optical carrier microwave according to an embodiment of the present disclosure is schematically shown.

[0097] As Figure 4 shown, the method includes operation S410 to operation S450.

[0098] In operation S410, a microwave signal and an optical wave signal are modulated by an electro-optic modulation unit to obtain an optical carrier microwave signal, and the optical carrier microwave signal is transmitted to an interference unit, where the interference unit is connected to the electro-optic modulation unit, and the interference unit has multiple measurement paths and a reference path, and each measurement path in the multiple measurement paths represents a distance to be measured.

[0099] In operation S420, the interference unit causes the optical carrier microwave signal to pass through multiple measurement paths to obtain measurement signals corresponding to each measurement path, passes through the reference path to obtain a reference signal, and couples the multiple measurement signals and the reference signal to obtain a coupled microwave signal.

[0100] In operation S430, the coupled microwave signal is converted into an electrical signal by a photoelectric detection unit.

[0101] In operation S440, a mixing unit mixes the electrical signal and the microwave signal according to the electrical signal to obtain a mixed microwave signal.

[0102] In operation S450, the amplitude of the electrical signal and the phase of the mixed microwave signal are detected by the amplitude processing unit, and the distance to be measured corresponding to each measurement path is determined according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

[0103] It should be noted that the distance measurement method part in the embodiments of the present disclosure corresponds to the distance measurement system part in the embodiments of the present disclosure. For the description of the distance measurement method part, please refer to the distance measurement system part specifically, and details will not be repeated here.

[0104] The present disclosure uses an electro-optic modulation unit to obtain an optical carrier microwave signal, designs multiple measurement paths and a reference path in the interference unit, the multiple measurement paths correspond to multiple distances to be measured, and the multiple measurement paths share the same electro-optic modulation unit and photoelectric detection unit.

[0105] The microwave signal is divided into two paths. One path is used to drive the electro-optic modulator to interfere the reference signal and the measurement signal, and convert the coupled microwave signal into an electrical signal; the other path is used as the local oscillator signal of the mixing unit to mix with the electrical signal in the mixing unit to obtain a mixed microwave signal. The microwave signal is also input into the system as a frequency-sweeping signal. The fast frequency sweep of the microwave signal enables the amplitude processing unit to analyze the amplitude of the electrical signal and the phase of the mixed microwave signal, calculate the optical path of each measurement signal, then separate the optical path information of each measurement signal, and finally calculate the corresponding distance information by solving the amplitude spectrum period of each measurement signal, realizing the synchronous solution of the multi-path distances to be measured.

[0106] The analysis of the amplitude and phase is based on the representation of the DC signal. Therefore, the sampling frequency requirement for the data acquisition unit is very low, there is no requirement for the sampling bandwidth, and the algorithms for data processing and distance calculation are relatively easy to implement, greatly reducing the amount of computation involved in the multi-path distance measurement method of the optical carrier microwave.

[0107] Figure 5 A block diagram of an electronic device suitable for implementing the multi-path distance measurement method based on optical carrier microwave according to an embodiment of the present disclosure is schematically shown. Figure 5 The shown electronic device is only an example and should not bring any limitation to the functions and usage scope of the embodiments of the present disclosure.

[0108] Such as Figure 5As shown, the electronic device 500 according to an embodiment of the present disclosure includes a processor 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a storage section 508 into a random access memory (RAM) 503. The processor 501 can include, for example, a general-purpose microprocessor (e.g., CPU), an instruction set processor, and / or a related chipset, and / or a dedicated microprocessor (e.g., an application specific integrated circuit (ASIC)), and so on. The processor 501 can also include on-board memory for caching purposes. The processor 501 can include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0109] In the RAM 503, various programs and data required for the operation of the electronic device 500 are stored. The processor 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. The processor 501 performs various operations of the method flow according to an embodiment of the present disclosure by executing the programs in the ROM 502 and / or the RAM 503. It should be noted that the programs can also be stored in one or more memories other than the ROM 502 and the RAM 503. The processor 501 can also perform various operations of the method flow according to an embodiment of the present disclosure by executing the programs stored in the one or more memories.

[0110] According to an embodiment of the present disclosure, the electronic device 500 can further include an input / output (I / O) interface 505, and the input / output (I / O) interface 505 is also connected to the bus 504. The electronic device 500 can further include one or more of the following components connected to the input / output (I / O) interface 505: an input section 506 including a keyboard, a mouse, etc.; an output section 507 including, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN card, a modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the input / output (I / O) interface 505 as needed. A removable medium 511, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 510 as needed so that a computer program read from it can be installed into the storage section 508 as needed.

[0111] According to an embodiment of the present disclosure, the method flow according to the embodiments of the present disclosure can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable storage medium, and the computer program includes program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 509, and / or installed from the removable medium 511. When the computer program is executed by the processor 501, the above functions defined in the system of the embodiments of the present disclosure are executed. According to an embodiment of the present disclosure, the above-described systems, devices, apparatuses, modules, units, etc. can be implemented by computer program modules.

[0112] The present disclosure also provides a computer-readable storage medium, which can be included in the device / device / system described in the above embodiments; or can exist separately without being assembled into the device / device / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiments of the present disclosure is implemented.

[0113] According to an embodiment of the present disclosure, the computer-readable storage medium can be a non-volatile computer-readable storage medium. For example, it can include but is not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In the present disclosure, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or combined with an instruction execution system, device, or device.

[0114] For example, according to an embodiment of the present disclosure, the computer-readable storage medium can include the above-described ROM 502 and / or RAM 503 and / or one or more memories other than ROM 502 and RAM 503.

[0115] An embodiment of the present disclosure also includes a computer program product, which includes a computer program, and the computer program includes program code for executing the method provided by the embodiments of the present disclosure. When the computer program product runs on an electronic device, the program code is used to cause the electronic device to implement the multi-path distance measurement method based on optically carried microwave provided by the embodiments of the present disclosure.

[0116] When the computer program is executed by the processor 501, the above functions defined in the system / device of the embodiments of the present disclosure are executed. According to an embodiment of the present disclosure, the above-described systems, devices, modules, units, etc. can be implemented by computer program modules.

[0117] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication section 509, and / or installed from the removable medium 511. The program code included in the computer program may be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0118] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiments of the present disclosure may be written in any combination of one or more programming languages. Specifically, these computing programs may be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages include but are not limited to, for example, Java, C++, Python, the "C" language, or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (for example, by connecting through an Internet service provider via the Internet).

[0119] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur in a different order than that noted in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and combinations of blocks in the block diagram or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or operations, or by a combination of dedicated hardware and computer instructions. Those skilled in the art will appreciate that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0120] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A multipath distance measurement system based on optical microwaves, comprising: an electro-optical modulation unit, used for modulating the microwave signal and the light wave signal to obtain a light-borne microwave signal, and transmitting the light-borne microwave signal to the interference unit; an interference unit connected to the electro-optical modulation unit, comprising a plurality of measurement paths and a reference path, wherein each of the plurality of measurement paths represents a distance to be measured, and the interference unit is used to make the light-carrying microwave signal pass through the plurality of measurement paths to obtain a measurement signal corresponding to each measurement path, pass through the reference path to obtain a reference signal, and couple the plurality of measurement signals with the reference signal to obtain a coupled microwave signal, wherein the plurality of measurement paths comprise a circulator and a plurality of collimators, and in each of the measurement paths, the light-carrying microwave signal passes through the circulator to reach the collimator, passes through the collimator to reach a measurement target corresponding to the measurement path, and passes through the measurement target corresponding to the measurement path to be reflected back to the collimator, and passes through the circulator to obtain the measurement signal corresponding to the measurement path, wherein the distance between the collimator and the measurement target is the distance to be measured; a photoelectric detection unit, connected to the interference unit, and used to convert the coupled microwave signal into an electrical signal; A frequency mixing unit, connected to the electro-optical modulation unit and the photoelectric detection unit, and configured to perform frequency mixing according to the electrical signal and the microwave signal to obtain a mixed microwave signal; An amplitude processing unit is connected to the photoelectric detection unit and the mixing unit, and is used to detect the amplitude of the electrical signal and the phase of the mixed microwave signal, and determine the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

2. The system according to claim 1, wherein: The reference path includes an optical fiber, the optical fiber connects the electro-optical modulation unit and the photoelectric detection unit, and the circulator in each of the measurement paths connects the electro-optical modulation unit and the photoelectric detection unit; In the reference path, the light-carrying microwave signal passes through the optical fiber to obtain the reference signal.

3. The system according to claim 1, wherein: The amplitude processing unit includes an amplitude detection subunit and a data processing subunit; The amplitude detection subunit is connected to the photoelectric detection unit and is used to detect the amplitude of the electrical signal; The data processing subunit is connected to the amplitude detection subunit and the mixing unit, and is used to detect the phase of the mixed microwave signal, and determine the distance to be measured corresponding to each measurement path according to the amplitude of the electrical signal and the phase of the mixed microwave signal.

4. The system according to claim 3, wherein: The amplitude detection subunit is used for obtaining the amplitude of the electric signal by integrating and performing square root operations on the square of the electric signal.

5. The system according to claim 4, wherein: The amplitude detection subunit integrates and performs square root operations on the square of the electrical signal based on an integral filter capacitor to obtain the amplitude of the electrical signal.

6. The system according to claim 3, wherein: The data processing subunit includes a data acquisition card and a lower computer; The data acquisition card is connected to the amplitude detection subunit and the frequency mixing unit, and is used to perform frequency scanning on the electrical signal to obtain the amplitude spectrum of the electrical signal, and detect the phase of the frequency mixing microwave signal; The lower computer is connected to the data acquisition card and is used to determine the distance to be measured corresponding to each measurement path according to the period of the amplitude spectrum and the phase of the mixed microwave signal.

7. The system according to any one of claims 1 to 3, wherein: The electro-optical modulation unit comprises a broadband light source, a microwave signal source and an electro-optical modulator; The broadband light source is connected to the electro-optic modulator and is used to generate the light wave signal; The microwave signal source is connected to the electro-optic modulator and the frequency mixing unit, and is used to generate the microwave signal; The electro-optic modulator is used to modulate the microwave signal and the light wave signal to obtain the light-carrying microwave signal.

8. The system according to any one of claims 1 to 3, wherein: The interference unit further includes a coupler, which is connected to the plurality of measurement paths and the reference path and is used to couple the plurality of measurement signals with the reference signal to obtain the coupled microwave signal.

9. A multipath distance measurement method based on optical microwaves, comprising: Modulating the microwave signal and the light wave signal through an electro-optical modulation unit to obtain a light-carrying microwave signal, and transmitting the light-carrying microwave signal to an interference unit, wherein the interference unit is connected to the electro-optical modulation unit, and the interference unit has a plurality of measurement paths and a reference path, and each of the plurality of measurement paths represents a distance to be measured; The interference unit is used to make the light-carrying microwave signal pass through the plurality of measurement paths to obtain a measurement signal corresponding to each measurement path, pass through the reference path to obtain a reference signal, and couple the plurality of measurement signals with the reference signal to obtain a coupled microwave signal, wherein the plurality of measurement paths include a circulator and a plurality of collimators, and in each measurement path, the light-carrying microwave signal passes through the circulator to reach the collimator, passes through the collimator to reach a measurement target corresponding to the measurement path, and is reflected back to the collimator through the measurement target corresponding to the measurement path, and passes through the circulator to obtain the measurement signal corresponding to the measurement path, wherein the distance between the collimator and the measurement target is the distance to be measured; Converting the coupled microwave signal into an electrical signal through a photoelectric detection unit; Performing mixing by a frequency mixing unit according to the electrical signal and the microwave signal to obtain a mixed microwave signal; The amplitude of the electrical signal and the phase of the mixed-frequency microwave signal are detected by an amplitude processing unit, and the distance to be measured corresponding to each measurement path is determined according to the amplitude of the electrical signal and the phase of the mixed-frequency microwave signal.

10. An electronic device, comprising: one or more processors; a memory for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement the method of claim 9.

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