CN112147623B - Multi-zone ranging method and system based on chaotic polarized radar - Google Patents

Abstract

The invention provides a multi-region ranging method and a system based on a chaotic polarized radar, wherein the method comprises the following steps: dividing a light beam emitted by the distributed feedback laser by a polarization controller to generate a polarized component light beam; wherein the polarized component beam comprises an x-polarized component beam and a y-polarized component beam; the polarized component light beam is divided into a reference signal and a detection signal by an optical fiber polarization beam splitter; the reference signal and the detection signal sequentially pass through the optical fiber beam splitter and the signal processing module to respectively obtain a reference current signal and a detection current signal; the reference current signal and the detection current signal pass through a calculation module to generate a position vector of a first ranging target; the calculation module comprises: and the correlation function calculation module and the target ranging calculation module. The invention has stable and high ranging resolution, strong noise immunity, low relative error required by measuring the multi-region target position vector in the complex shape, and great potential for intelligent precision machining and complex shape target quality detection.

Description

A multi-region ranging method and system based on chaotic polarization radar

Technical Field

The present invention relates to the technical field of textile sorting, and in particular to a multi-region distance measurement method and system based on chaotic polarization radar.

Background Art

With the rapid development of artificial intelligence, lidar is expected to achieve the following functions by sensing the surrounding environment: accurate target ranging, high-quality 3D imaging, target tracking and recognition, automatic positioning and mapping.

At present, most lidar ranging solutions use pulsed lasers and continuous wave lasers as light sources to obtain better signal-to-noise ratio and measurement range. However, radar ranging based on pulsed lasers and continuous wave lasers has disadvantages such as low resolution, high interception probability, weak anti-interference ability, and high cost.

Compared with ranging using pulsed lasers and continuous wave lasers, ranging based on chaotic laser radar (CLR) generated by the nonlinear dynamics of semiconductors with optical feedback or light injection has many advantages, such as low probability of interception, strong anti-interference ability and low cost. In addition, it also has high resolution thanks to the wide bandwidth of optical chaos. Finally, due to the sensitivity of chaotic radar to laser parameters, it is easy to generate and control.

However, firstly, the resolution of CLR ranging is largely limited by the bandwidth of chaotic lasers. Further improvement of ranging resolution requires ultrafast chaotic lasers with large modulation bandwidth. Secondly, in the current CLR ranging work, the measured target plane is smooth and flat. CLR is usually used for fixed points in the target, and it is difficult to apply them to intelligent precision machining and quality inspection of complex-shaped targets. The scheme and method of CLR ranging cannot fully detect the distance of different areas of the target and are not suitable for accurate ranging of the entire area of complex-shaped targets. Finally, the detection waveform based on CLR is not modulated before target ranging, which reduces the resolution and accuracy of target ranging.

Summary of the invention

The invention provides a multi-region distance measurement method and system based on chaotic polarization radar, which realizes accurate distance measurement of multiple regions of two targets with complex shapes by utilizing two chaotic polarization waveforms modulated by random noise.

An embodiment of the present invention provides a multi-region ranging method based on chaotic polarization radar, comprising:

The light beam emitted by the distributed feedback laser is split by a polarization controller to generate polarization component beams; wherein the polarization component beams include an x-polarization component beam and a y-polarization component beam;

The polarized component light beam is divided into a reference signal and a detection signal by a fiber polarization beam splitter;

The reference signal and the detection signal are respectively passed through the optical fiber beam splitter and the signal processing module in sequence to obtain a reference current signal and a detection current signal;

The reference current signal and the detection current signal are passed through a calculation module to generate a position vector of a first ranging target; the calculation module includes: a correlation function calculation module and a target ranging calculation module.

Furthermore, the reference signal and the detection signal are respectively passed through the optical fiber beam splitter and the signal processing module in sequence to obtain a reference current signal and a detection current signal, including:

The detection signal is divided into at least one chaotic radar detection waveform by a first optical fiber beam splitter;

The chaotic radar detection waveform is passed through a signal processing module to obtain an incident photocurrent signal; wherein the signal processing module includes: a first noise modulator, a first signal converter, a signal amplifier and a signal transmitter;

The incident photocurrent signal is transmitted to the first ranging target, and an outgoing photocurrent signal is obtained through an optical reaction; wherein the optical reaction includes: reflection and/or scattering;

The output photocurrent signal passes through a signal receiver and a signal amplifier in sequence to obtain a detection current signal.

Furthermore, the reference signal and the detection signal are respectively passed through the optical fiber beam splitter and the signal processing module in sequence to obtain a reference current signal and a detection current signal, and further comprising:

The reference signal is divided into at least one chaotic radar reference waveform by a second optical fiber beam splitter;

The chaotic radar reference waveform is passed through a signal processing module to obtain a reference current signal; the signal processing module includes: a second noise modulator and a second signal converter.

Furthermore, the reference current signal and the detection current signal calculation module generate the position vector of the first ranging target, including:

Calculating the signal correlation between the reference current signal and the detection current signal through a correlation function calculation module;

The position vector of the first ranging target is generated through the target ranging calculation module and the signal correlation.

Furthermore, the light beam emitted by the distributed feedback laser is split by a polarization controller to generate polarized component light beams, including:

The light beam emitted by the distributed feedback laser is converted into a unidirectional propagating light beam through an optical isolator;

The unidirectionally propagating light beam is split by a polarization controller to generate polarization component light beams.

An embodiment of the present invention provides a multi-region ranging system based on chaotic polarization radar, comprising:

A polarization controller splitting module, used for splitting the light beam emitted by the distributed feedback laser through the polarization controller to generate polarization component light beams; wherein the polarization component light beams include an x-polarization component light beam and a y-polarization component light beam;

An optical fiber polarization beam splitter splitting module, used for dividing the polarization component light beam into a reference signal and a detection signal through an optical fiber polarization beam splitter;

A reference current signal and a detection current signal acquisition module, which is used for the reference signal and the detection signal to pass through the optical fiber beam splitter and the signal processing module in sequence to obtain the reference current signal and the detection current signal;

The position vector calculation module is used for the reference current signal and the detection current signal to generate the position vector of the first ranging target through the calculation module; the calculation module includes: a correlation function calculation module and a target ranging calculation module.

Furthermore, the reference current signal and detection current signal acquisition module includes: a detection current signal acquisition submodule, which is used for the following steps:

The detection signal is divided into at least one chaotic radar detection waveform by a first optical fiber beam splitter;

The chaotic radar detection waveform is passed through a signal processing module to obtain an incident photocurrent signal; wherein the signal processing module includes: a first noise modulator, a first signal converter, a signal amplifier and a signal transmitter;

The incident photocurrent signal is transmitted to the first ranging target, and an outgoing photocurrent signal is obtained through an optical reaction; wherein the optical reaction includes: reflection and/or scattering;

The output photocurrent signal passes through a signal receiver and a signal amplifier in sequence to obtain a detection current signal.

Furthermore, the reference current signal and detection current signal acquisition module further includes: a reference current signal acquisition submodule, which is used for the following steps:

The reference signal is divided into at least one chaotic radar reference waveform by a second optical fiber beam splitter;

The chaotic radar reference waveform is passed through a signal processing module to obtain a reference current signal; the signal processing module includes: a second noise modulator and a second signal converter.

Furthermore, the position vector calculation module is also used for:

Calculating the signal correlation between the reference current signal and the detection current signal through a correlation function calculation module;

The position vector of the first ranging target is generated through the target ranging calculation module and the signal correlation.

Furthermore, the polarization controller splitting module is also used for:

The light beam emitted by the distributed feedback laser is converted into a unidirectional propagating light beam through an optical isolator;

The unidirectionally propagating light beam is split by a polarization controller to generate polarization component light beams.

Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

An embodiment of the present invention provides a multi-region ranging method based on chaotic polarization radar, including: the light beam emitted by the distributed feedback laser is split by a polarization controller to generate polarization component beams; wherein the polarization component beams include an x polarization component beam and a y polarization component beam; the polarization component beams are divided into a reference signal and a detection signal by an optical fiber polarization beam splitter; the reference signal and the detection signal pass through the optical fiber beam splitter and the signal processing module in turn to obtain a reference current signal and a detection current signal respectively; the reference current signal and the detection current signal pass through a calculation module to generate a position vector of a first ranging target; the calculation module includes: a correlation function calculation module and a target ranging calculation module. The present invention has stable and high ranging resolution, strong anti-noise performance, and low relative error required for measuring the position vectors of multi-region targets in complex shapes, and has great potential for intelligent precision machining and complex shape target quality detection.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a flow chart of a multi-region ranging method based on chaotic polarization radar provided by an embodiment of the present invention;

FIG2 is a flow chart of a multi-region ranging method based on chaotic polarization radar provided by another embodiment of the present invention;

FIG3 is a schematic diagram of the present invention for realizing accurate ranging of multiple regions of two complex-shaped targets;

FIG4 is a geometric diagram of arbitrary small area ranging of a complex shape target according to the present invention;

FIG5 is a time trajectory diagram of a light beam after noise modulation according to the present invention;

FIG6 is a function graph of the beam correlation of the present invention;

FIG7 is a function graph of the time and space correlation of the light beam of the present invention;

FIG8 is a geometric diagram of the distance measurement of 10 small areas of a complex-shaped target according to the present invention;

FIG9 is a function image of the time and space correlation of the received signal of the present invention;

FIG10 is a functional graph showing the variation of the ranging resolution with the noise intensity β of the present invention;

11 is a device diagram of a multi-region ranging system based on chaotic polarization radar provided by an embodiment of the present invention;

FIG. 12 is a device diagram of a multi-region ranging system based on chaotic polarization radar provided by another embodiment of the present invention.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and/or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or combinations thereof.

The term "and/or" means and includes any and all possible combinations of one or more of the associated listed items.

The first aspect.

Based on light-injected optically pumped spin VCSEL, we proposed a new scheme for accurate ranging of multiple regions in two complex-shaped targets by modulating two chaotic polarimetric radars with random noise. Here, the two modulated chaotic polarimetric radars have the excellent characteristics of spatiotemporal uncorrelation and femtosecond dynamics. Using these characteristics, the reflected chaotic polarimetric detection waveforms with delayed signals and the corresponding reference waveforms can be correlated to achieve accurate ranging of the position vectors of multiple regions of two complex-shaped targets. Further research shows that the ranging of multi-region small targets has a very low relative error of less than 0.23%. Their distance resolution is very stable, reaching 0.2mm, and has excellent strong anti-noise performance. The accurate ranging of multi-region small targets by light-injected optically pumped spin VCSEL provides a good prospect for potential applications in intelligent precision processing and quality inspection of complex-shaped targets.

Referring to FIG. 1 , an embodiment of the present invention provides a multi-region ranging method based on chaotic polarization radar, comprising:

S10. The light beam emitted by the distributed feedback laser is split by a polarization controller to generate polarization component beams; wherein the polarization component beams include an x-polarization component beam and a y-polarization component beam.

S20, the polarization component light beam is divided into a reference signal and a detection signal by a fiber polarization beam splitter.

S30, the reference signal and the detection signal are respectively passed through the optical fiber beam splitter and the signal processing module in sequence to obtain a reference current signal and a detection current signal.

S40, the reference current signal and the detection current signal are used to generate a position vector of a first ranging target through a calculation module; the calculation module includes: a correlation function calculation module and a target ranging calculation module.

Please refer to FIG. 2 . In a specific embodiment, S30 , the reference signal and the detection signal are respectively passed through the optical fiber beam splitter and the signal processing module in sequence to obtain the reference current signal and the detection current signal, including:

S311. The detection signal is divided into at least one chaotic radar detection waveform by a first optical fiber splitter.

S312. The chaotic radar detection waveform is passed through a signal processing module to obtain an incident photocurrent signal; wherein the signal processing module includes: a first noise modulator, a first signal converter, a signal amplifier and a signal transmitter.

S313, the incident photocurrent signal is transmitted to the first ranging target, and an output photocurrent signal is obtained through an optical reaction; wherein the optical reaction includes: reflection and/or scattering.

S314, the output photocurrent signal passes through a signal receiver and a signal amplifier in sequence to obtain a detection current signal.

Please refer to FIG. 2 . In a specific embodiment, S30 , the reference signal and the detection signal are respectively passed through the optical fiber beam splitter and the signal processing module in sequence to obtain the reference current signal and the detection current signal, including:

S321. The reference signal is divided into at least one chaotic radar reference waveform by a second optical fiber splitter.

S322. The chaotic radar reference waveform is passed through a signal processing module to obtain a reference current signal; the signal processing module includes: a second noise modulator and a second signal converter.

Please refer to FIG. 2 , in a specific embodiment, S40, the reference current signal and the detection current signal calculation module generates the position vector of the first ranging target, including:

S41. Calculate the signal correlation between the reference current signal and the detection current signal through a correlation function calculation module.

S42. Generate a position vector of the first ranging target through a target ranging calculation module and the signal correlation.

Please refer to FIG. 2 , in a specific embodiment, S10, the light beam emitted by the distributed feedback laser is split by a polarization controller to generate polarized component light beams, including:

S11. The light beam emitted by the distributed feedback laser is converted into a unidirectional propagating light beam through an optical isolator.

S12, the unidirectionally propagating light beam is split by a polarization controller to generate polarization component light beams.

Please refer to FIG. 3 . In a specific embodiment, two chaotic polarization waveforms are used in a light-injected optically pumped spin VCSEL to achieve accurate ranging of multiple regions of two complex-shaped targets. Among them, the DFB is a distributed feedback laser as an external light source. The optical isolator (OI) with the subscript 1-2 is used to ensure the unidirectional propagation of light waves. The neutral density filter (NDF) is used to control the intensity of the injected light field from the DFB. In order to ensure that the polarized light of the DFB is injected into the x-polarization component (PC) and y-PC of the optically pumped spin VCSEL in parallel, the polarized light output from the DFB needs to be split and adjusted into x-PC and y-PC through a polarization control optical path (PCOC). In the PCOC, the switching between x-PC and y-PC is achieved by some passive devices, such as a fiber polarizer (FP), a fiber polarization controller (FPCO), a fiber depolarizer (FD), and a fiber polarization coupler (FPC). Target 1 (T1) and target T2 are complex-shaped targets to be measured. PD is a photodetector. AM is an amplitude modulator. EA is an electrical amplifier. TA and RA are the transmitting antenna and receiving antenna, respectively. The fiber polarization beam splitter (FPBS) splits the chaotic light waves generated by injecting light into the optically pumped spin VCSEL into two PCs, which are defined as x-polarized chaotic laser radar (XP-CLR) and y-polarized chaotic laser radar (YP-CLR). XP-CLR is further split into two light waves by 1×1 fiber beam splitter 1 (FBS1). One of them is used as a reference signal (RS) and the other is used as a detection signal (PS). For the convenience of discussion, they are named XP-CLR-RS and XP-CLR-PS, respectively. At the same time, FBS2 further splits YP-CLR into two beams, one of which is used as RS and the other as PS. They are named YP-CLR-RS and YP-CLR-PS, respectively.

For the ranging of complex-shaped target T ₁ , XP-CLR-PS is divided into N beams of chaotic radar detection waveforms by 1×N FBS ₁ , which are modulated with random noise by using AMs with subscripts 11-1N. These modulated detection waveforms are converted into N beams of probe current signals by PDs with subscripts 11-1N, and then amplified by EAs with subscripts 11-1N. These amplified current signals are transmitted to multiple areas of T ₁ by TAs with subscripts 11-1N. After being reflected or scattered by multiple areas of T ₁ , they first have delay information, and then are received by RA ₁ and amplified by EA _2. On the other hand, XP-CLR-RS is divided into N beams of reference waveforms by 1×N FBS ₂ , which are modulated with random noise by using AMs with subscripts 21-2N. These modulated reference waveforms are converted into N beams of reference current signals by PDs with subscripts 21-2N. The correlation between the detection current signal and its corresponding reference current signal can be calculated by using the correlation function calculation module (CFCM). By observing the time position of the maximum expected value of the correlation, the position vectors of multiple regions of _T1 can be further calculated using the target range calculation module (TRCM). Similarly, the position vectors of multiple regions of _T2 can be obtained by TRCM.

For spin VCSELs, the left-handed and right-handed circularly polarized components of the light field can be re-expressed in terms of orthogonal linear components as:

Where E ₊ and E _- are the complex amplitudes of the left and right circular polarization components, respectively, and _Ex and _Ey are the complex amplitudes of the two orthogonal linear components x-PC and y-PC, respectively. Based on formula (1), the four coupling rate equations of the light-injected optically pumped spin VCSEL can be shown as follows:

Wherein, the subscripts x and y denote x-PC and y-PC, respectively. The circularly polarized field component is coupled through the crystal birefringence and is characterized by the rate _γp and the dichroism _γa . The normalized carrier variables M and n of formulas (2)-(5) are defined as M=(n ₊₊ n _- )/2andn=(n ₊ -n _- )/2, where n ₊ and _n- are the corresponding normalized densities of spin-down and spin-up electrons, respectively. k is the cavity decay rate and a is the linewidth gain factor. γ is the electron density decay rate. _γs is the spin relaxation rate. η is the total normalized pump power. P is the pump polarization ellipticity. _kxinj and _kyinj are the external injection intensities of x-PC and y-PC, respectively; β is the spontaneous scattering coefficient, also known as the noise intensity. _ξ1 and _ξ2 are both independent Gaussian white noises with mean 0 and variance 1, where Δω is the frequency detuning between the center frequency of the DFB and the reference frequency of the spinning VCSEL.

As shown in Figure 4, by using N beams of chaotic polarization radar detection waves at the same time, any small area in T ₁ or T ₂ can be detected. After being reflected or scattered at the target, N beams of chaotic polarization radar detection waveforms with different delays are received by RA at the same time. In this case, according to the correlation theory, in order to easily detect the position vector of each small area, the N beams of XP-CLR-PSs and the N beams of YP-CLR-PSs need to satisfy orthogonal irrelevance in time and orthogonal irrelevance in space. In order to meet these conditions, the N beams of XP-CLR-PSs and the N beams of YP-CLR-PSs are modulated with random noise, that is:

Similarly, random noise is used to modulate N beams of XP-CLR-RSs and N beams of YP-CLR-RSs, which can be expressed as:

Wherein, subscripts 1 and 2 represent PS and RS respectively. and are the complex amplitudes of the j-th XP-CLR-RSs and the j-th YP-CLR-RSs, respectively. and are the complex amplitudes of the j-th XP-CLR-PSs and the j-th YP-CLR-PSs, respectively. ζ is random noise. According to formulas (6)-(9), N beams of XP-CLR-PSs or N beams of YP-CLR-PSs are orthogonal to each other and can be expressed in space by cross-correlation as follows:

and

Moreover, the jth bundle in XP-CLR-PSs or the jth bundle in YP-CLR-PSs is uncorrelated at different times, which can be expressed by temporal autocorrelation as:

Since XP-CLR-RS and YP-CLR-RS are the replica samples of XP-CLR-PS and YP-CLR-PS respectively, the j-th beam of XP-CLR-PS and its corresponding reference signal are mutually orthogonal. Similarly, the j-th beam of YP-CLR-PS and its corresponding reference signal can also be mutually orthogonal. They are expressed in space by cross-correlation as:

The temporal cross-correlation between the j-th XP-CLR-PS and its corresponding reference signal and the temporal cross-correlation between the j-th YP-CLR-PS and its corresponding reference signal are expressed as:

From formulas (10)-(17), we can derive the correlation functions of N-beam XP-CLR-PSs and N-beam YP-CLR-PSs in time and space, respectively, as follows:

The temporal and spatial correlation functions of N beams of XP-CLR-PSs and their corresponding reference signals and N beams of YP-CLR-PSs and their corresponding reference signals can be expressed as:

As shown in Figure 4, we use the modulated N-beam XP-CLR-PSs and N-beam YP-CLR-PSs to detect the target point (A) in the small area of T ₁ (T ₂ ), and receive the reflected or scattered signals through RA ₁ (RA ₂ ). Therefore, the received signals of RA ₁ and RA ₂ can be written as

Where τ _1,j and τ _2,j are the time delays from TA _1j to RA ₁ and from TA _2j to RA ₂ , respectively. Therefore, according to equations (20)-(22), the cross-correlation function of the received signal from RA ₁ and the jth beam XP-CLR-RS can be obtained as

The cross-correlation function between the received signal from RA ₁ and the j-th YP-CLR-RS beam is

Where _Tint is the effective correlation time. The time delays τ _1,j and τ _2,j can be estimated as the values corresponding to the maximum position, respectively, as follows

in, is the expected value. As shown in Figure 4, the actual position vector of point A is set to r _A , and the position vector of the j-th beam XP-CLR-PS or j-th beam YP-CLR-PS to be measured is set to r _Aj . The position vectors of the transmitting antennas TA _1j and TA _2j are set to r _1j and r _2j , respectively. The position vectors of the receiving antennas RA ₁ and RA ₂ are set to r _r1 and r _r2 . According to the geometric relationship of point A, we get

From formula (26), we can solve We use the almost equal equations to solve the position vector of point A. We take the average value as the exact position vector of point A and express it as

Table 1. Parameter values used in the calculations for the system

The parameter values used in the following calculations are given in Table 1. Using formulas (6)-(9), we calculated and The time trajectory after random noise modulation is shown in Figure 5. In the figure, and They are the first beam XP-CLR-PS and the first beam YP-CLR-PS respectively. and They are the first beam of XP-CLR-RS and the first beam of YP-CLR-RS. As can be seen from Figure 5, and The time trajectories of all beams show chaotic states and fast dynamic characteristics at the femtosecond level, indicating that XP-CLR-PS, YP-CLR-PS, XP-CLR-RS and YP-CLR-RS show chaotic time trajectories with fast dynamic characteristics. These modulated chaotic radar elements from XP-CLR-PS or YP-CLR-PS all satisfy the irrelevance in time and space (see equations (10)-(13)). In order to understand their irrelevance, we take the 5th beam XP-CLR-PS and the 5th beam YP-CLR-PS as examples to calculate their autocorrelations ( _TPx and _TPy ) at different times and their cross-correlations ( _RPx and _RPy ) in space, as shown in Figure 6.

From Figure 6, we can see that the maximum values of T _Px and T _Py appear at t = 0. Except for t = 0, the values of T _Px and T _Py at other times are almost 0. The peak values of R _Px and R _Py appear at j = 5. At other j values except 5, their values are equal to 0. According to (18)-(21), the spatiotemporal evolution of the correlation functions of 10-beam XP-CLR-PSs and 10-beam YP-CLR-PSs are shown in Figures 7(a) and 7(b), respectively: and Figure 7(c) shows the temporal and spatial correlations between 10 XP-CLR-PSs and 10 XP-CLR-RSs. Figure 7(c) shows the temporal and spatial correlations between 10 YP-CLR-PSs and 10 YP-CLR-RSs. From Figures 7(a) and 7(b), we can see that for the Nth beam XP-CLR-PS, The maximum value of appears at t = 0 and j = N (N = 1, 2, 3, ..., 10, the same below). The maximum value appears at t = 0 and j = N. As shown in Figure 7(c), for the Nth XP-CLR-PS and Nth XP-CLR-RS The maximum value appears at t = 0 and j = N. As can be seen from Figure 7(d), for the Nth YP-CLR-PS and Nth YP-CLR-RS The maximum value appears at t = 0 and j = N. These indicate that XP-CLR-PS and YP-CLR-PS have the characteristics of temporal and spatial incorrelation. Similarly, the temporal and spatial incorrelation of N beams of XP-CLR-PSs and their corresponding reference signals, as well as the temporal and spatial incorrelation of N beams of YP-CLR-PSs and their corresponding reference signals can be achieved. Below, based on their temporal and spatial incorrelation, 12 small areas in complex shape targets T ₁ and T ₂ are taken as examples to discuss their ranging.

As shown in Figure 8, we give the ranging geometry of 12 small areas in complex shape targets T ₁ and T _2. As shown in Figure 8(a), the 12 small areas in T ₁ are defined as A ₁ -A ₁₂ , and then their position vectors are regarded as The 10 beams of XP-CLR-PSs transmitted by the transmitting antennas (TA _1,1 -TA _1,10 ) are used to detect the distances of targets A ₁ -A ₁₂ in sequence. The position vectors of these transmitting antennas are assumed to be r _1,1 -r _1,10 in sequence. As shown in Figure 8(b), 12 small areas in T ₂ are defined as A' ₁ -A' ₁₂ , and their position vectors are considered to be Ten beams of XP-CLR-PSs transmitted by the transmitting antennas (TA _2,1 -TA _2,10 ) are used to detect the distances of targets A' ₁ -A' ₁₂ in sequence. The position vectors of these transmitting antennas are assumed to be r _2,1 -r _2,10 in sequence. In addition, these transmitting antennas (TA _1,1 -TA _1,10 and TA _2,1 -TA _2,10 ) are arranged linearly with a distance of 0.5m between antennas.

In order to verify the feasibility of measuring the distance between two groups of small areas of 10 targets, we assume that the actual distances of targets A ₁ -A ₁₂ are The actual distances of targets _A'1 - _A'12 are assumed to be The values of these actual distances are given in Tables (3) and (4). The position vectors of the two sets of transmitting antennas (TA _1,1 -TA _1,10 and TA _2,1 -TA _2,10 ) are listed in Table 2. To further describe the accuracy of the two sets of 12 targets in a small area, we introduce their relative errors as follows:

Among them, j=1,2,3,…,12.

The measured position vectors of the targets in two groups of 12 small areas can be obtained by using equations (26) and (27). The two groups of delay times (τ _1,1 -τ _1,10 and τ _2,1 -τ _2,10 ) can be obtained by applying the maximum expected values of the correlation operations CC ₁ and CC ₂ given in equation (25). Below, the ranging process of small area A ₁ is explained as an example. The received signal from RA ₁ , including 10 beams of XP-CLR-PSs from TA _1,1 -TA _1,10 transmitting antennas, is used to detect target A _1. We calculate the cross-correlation of the received signal from RA ₁ and the 10 beams of XP-CLR-RSs in time and space (CC _1,1 -CC _1,10 ), as shown in Figure 9(b). It can be seen from the figure that the maximum expected value of the cross-correlation is located at 10 different time delays in turn. The 10 time delays can be obtained from Figures 9(a) and 9(c): τ ₁ = 34.149ns; τ ₂ = 32.770ns; τ ₃ = 31.443ns; τ ₄ = 30.182ns; τ ₅ = 29.004ns; τ ₆ = 27.932ns; τ ₇ = 26.994ns; τ ₈ = 26.222ns; τ ₉ = 25.652ns; τ ₁₀ = 25.316ns. Based on these time delays, we can use formulas (26)-(28) to obtain the target's precise measured position vector Similarly, the measured position vectors of the remaining small areas (A ₂ -A ₁₂ ) in T ₁ can be obtained, as shown in Table 3. In the same way, the position vectors of the small areas (A' ₁ -A' ₁₂ ) in T ₂ can be calculated, as shown in Figure 6. Therefore, according to formula (29), we obtain the relative errors of the ranging of the 12 small areas in T ₁ and T ₂ , as shown in Tables 3 and 4. From Tables 3 and 4, we can observe that the relative error of the ranging of the small targets in A ₁ -A ₁₂ is between 0.04% and 0.23%. The relative error of the ranging of the 12 small targets in area A' ₁ -A' ₁₂ is between 0 and 0.23%. These results show that the multi-area ranging of two complex shape targets has a small relative error, which is less than 0.23%.

Table 2. Position vectors of two groups of transmitting radars (TA _1,1 -TA _1,10 and TA _2,1 -TA _2,10 )

Table 3. Actual position vectors of the targets in the 12 small regions in _{T 1} and the measured position vector and their relative errors.

Table 4. Actual position vectors of the targets in the 12 small regions in _{T 2} and the measured position vector and their relative errors.

As is known to all, the full width at half maximum (FWHM) of the correlation peak is usually used to describe the ranging resolution. As shown in Figure 9(d), the corresponding peak FWHM of CC _1,1 is 4/3ps, and the ranging resolution is 0.2mm. It can be seen from Figure 9(c) that the FWHMs of the correlation operation (CC _1,1 -CC _1,10 ) are all 4/3ps, which means that the ranging resolution of all small targets A ₁ -A ₁₂ in T ₁ can reach 0.2mm. Similarly, the ranging resolution of all small targets A' ₁ -A' ₁₂ in T ₂ can also reach 0.2mm. In order to observe the influence of the two key parameters of injection intensity and noise intensity on the ranging resolution, Figure 10 shows the influence of the injection intensity k _xinj (k _yinj. ) and the noise intensity β on the ranging resolution of targets A ₁ -A ₁₂ and A' ₁ -A' ₁₂ . As can be seen from the figure, their range resolution always remains at 0.2mm and is independent of the injection intensity and noise intensity. The results show that by using two chaotic polarization radars modulated by random noise, it is possible to achieve ranging of multiple areas of two complex-shaped targets with a ranging resolution of up to 0.2mm. They also have excellent strong noise immunity.

In summary, we propose a novel scheme for accurate ranging of multiple regions in two complex-shaped targets, using two chaotic polarimeter radars generated by light-injection optically pumped spin VCSELs, where the two chaotic polarimeter radars are modulated with random noise. The two modulated chaotic polarimeter radars have excellent characteristics such as spatiotemporal uncorrelation and fast dynamic characteristics in the order of femtoseconds. Using these characteristics, the delay times from multiple regions can be obtained by observing the time position corresponding to the maximum expected value of the cross-correlation between the chaotic polarimeter detection waveform and its corresponding reference waveform. Based on these delay times, the position vectors of multiple regions in two complex-shaped targets can be accurately measured. The results show that the relative error of ranging of multi-region small targets is very low and less than 0.23%. Their resolution is very stable, up to 0.2mm, and they have excellent strong noise resistance. The attractive advantages of our proposed scheme for ranging of multi-region small targets are: stable and high ranging resolution, strong noise resistance, and low relative error required to measure the position vectors of multi-region targets in complex shapes. The ranging ideas and methods proposed in our scheme have great potential for intelligent precision machining and quality inspection of complex-shaped targets.

The second aspect.

Referring to FIG. 11 , an embodiment of the present invention provides a multi-region ranging system based on chaotic polarization radar, including:

The polarization controller splitting module 10 is used to split the light beam emitted by the distributed feedback laser through the polarization controller to generate polarization component beams; wherein the polarization component beams include an x-polarization component beam and a y-polarization component beam.

In a specific implementation, the polarization controller segmentation module 10 is further used for:

The light beam emitted by the distributed feedback laser is converted into a unidirectional propagating light beam through an optical isolator;

The unidirectionally propagating light beam is split by a polarization controller to generate polarization component light beams.

The optical fiber polarization beam splitter division module 20 is used to split the polarization component light beam into a reference signal and a detection signal through an optical fiber polarization beam splitter.

The reference current signal and detection current signal acquisition module 30 is used for the reference signal and the detection signal to pass through the optical fiber beam splitter and the signal processing module in sequence to obtain the reference current signal and the detection current signal.

The position vector calculation module 40 is used for the reference current signal and the detection current signal to generate the position vector of the first ranging target through the calculation module; the calculation module includes: a correlation function calculation module and a target ranging calculation module.

In a specific implementation, the position vector calculation module 40 is further used to:

Calculating the signal correlation between the reference current signal and the detection current signal through a correlation function calculation module;

The position vector of the first ranging target is generated through the target ranging calculation module and the signal correlation.

Please refer to FIG. 12 . In a specific embodiment, the reference current signal and detection current signal acquisition module 30 includes: a detection current signal acquisition submodule 31, which is used for the following steps:

The detection signal is divided into at least one chaotic radar detection waveform by a first optical fiber beam splitter;

The chaotic radar detection waveform is passed through a signal processing module to obtain an incident photocurrent signal; wherein the signal processing module includes: a first noise modulator, a first signal converter, a signal amplifier and a signal transmitter;

The incident photocurrent signal is transmitted to the first ranging target, and an outgoing photocurrent signal is obtained through an optical reaction; wherein the optical reaction includes: reflection and/or scattering;

The output photocurrent signal passes through a signal receiver and a signal amplifier in sequence to obtain a detection current signal.

Please refer to FIG. 12 . In a specific embodiment, the reference current signal and detection current signal acquisition module 30 further includes: a reference current signal acquisition submodule 32, which is used for the following steps:

The reference signal is divided into at least one chaotic radar reference waveform by a second optical fiber beam splitter;

The chaotic radar reference waveform is passed through a signal processing module to obtain a reference current signal; the signal processing module includes: a second noise modulator and a second signal converter.

Claims (8)

1. A multi-region ranging method based on chaotic polarization radar, which is characterized by including: The beam emitted by the distributed feedback laser is divided by the polarization controller to generate a polarized component beam; wherein the polarized component beam includes an x-polarized component beam and a y-polarized component beam; The polarized component beam is divided into a reference signal and a detection signal through an optical fiber polarization beam splitter; The reference signal and the detection signal pass through the optical fiber beam splitter and the signal processing module in sequence, respectively, to obtain the reference current signal and the detection current signal; The reference current signal and the detection current signal pass through a calculation module to generate a position vector of the first ranging target; the calculation module includes: a correlation function calculation module and a target ranging calculation module; The reference signal and detection signal pass through the optical fiber beam splitter and signal processing module in sequence to obtain the reference current signal and detection current signal, including: The detection signal is divided into at least one chaotic radar detection waveform through a first optical fiber beam splitter; The chaotic radar detection waveform passes through the signal processing module to obtain the incident photocurrent signal; wherein the signal processing module includes: a first noise modulator, a first signal converter, a signal amplifier and a signal transmitter; The incident photocurrent signal is emitted to the first ranging target, and an outgoing photocurrent signal is obtained through an optical reaction; wherein the optical reaction includes: reflection and/or scattering; The emitted photocurrent signal passes through a signal receiver and a signal amplifier in sequence to obtain a detection current signal; The first noise modulator is used to modulate the chaotic radar detection waveform to be orthogonally uncorrelated in time and orthogonally uncorrelated in space. 2. A multi-region ranging method based on chaotic polarization radar as claimed in claim 1, characterized in that the reference signal and the detection signal pass through the optical fiber beam splitter and the signal processing module in sequence to obtain the reference current signal and Detecting current signals also includes: The reference signal is divided into at least one chaotic radar reference waveform through a second optical fiber beam splitter; The chaotic radar reference waveform passes through a signal processing module to obtain a reference current signal; the signal processing module includes: a second noise modulator and a second signal converter. 3. A multi-region ranging method based on chaotic polarization radar as claimed in claim 1, characterized in that the reference current signal and the detection current signal calculation module generate the position vector of the first ranging target. ,include: Calculate the signal correlation between the reference current signal and the detection current signal through a correlation function calculation module; The position vector of the first ranging target is generated through the target ranging calculation module and the signal correlation. 4. A multi-region ranging method based on chaotic polarization radar as claimed in claim 1, characterized in that the beam emitted by the distributed feedback laser is divided by a polarization controller to generate a polarized component beam, including: The beam emitted by the distributed feedback laser passes through the optical isolator to generate a unidirectional propagation beam; The unidirectionally propagating light beam is divided by a polarization controller to generate polarized component light beams. 5. A multi-region ranging system based on chaotic polarization radar, which is characterized by including: A polarization controller splitting module is used to split the beam emitted by the distributed feedback laser through the polarization controller to generate a polarization component beam; wherein the polarization component beam includes an x-polarization component beam and a y-polarization component beam; An optical fiber polarization beam splitter splitting module, used for the polarization component beam to be divided into a reference signal and a detection signal through the optical fiber polarization beam splitter; The reference current signal and the detection current signal acquisition module are used for the reference signal and the detection signal to pass through the optical fiber beam splitter and the signal processing module in sequence to obtain the reference current signal and the detection current signal; A position vector calculation module is used to generate the position vector of the first ranging target through the calculation module of the reference current signal and the detection current signal; the calculation module includes: a correlation function calculation module and a target ranging calculation module; The reference current signal and detection current signal acquisition module includes: a detection current signal acquisition sub-module, which is used for the following steps: The detection signal is divided into at least one chaotic radar detection waveform through a first optical fiber beam splitter; The chaotic radar detection waveform passes through the signal processing module to obtain the incident photocurrent signal; wherein the signal processing module includes: a first noise modulator, a first signal converter, a signal amplifier and a signal transmitter; The first noise modulator is used to modulate the chaotic radar detection waveform to be orthogonally uncorrelated in time and orthogonally uncorrelated in space; The incident photocurrent signal is emitted to the first ranging target, and an outgoing photocurrent signal is obtained through an optical reaction; wherein the optical reaction includes: reflection and/or scattering; The emitted photocurrent signal passes through a signal receiver and a signal amplifier in sequence to obtain a detection current signal. 6. A multi-region ranging system based on chaotic polarization radar as claimed in claim 5, characterized in that the reference current signal and detection current signal acquisition module further includes: a reference current signal acquisition sub-module for Following steps: The reference signal is divided into at least one chaotic radar reference waveform through a second optical fiber beam splitter; The chaotic radar reference waveform passes through a signal processing module to obtain a reference current signal; the signal processing module includes: a second noise modulator and a second signal converter. 7. A multi-region ranging system based on chaotic polarization radar as claimed in claim 5, characterized in that the position vector calculation module is also used to: Calculate the signal correlation between the reference current signal and the detection current signal through a correlation function calculation module; The position vector of the first ranging target is generated through the target ranging calculation module and the signal correlation. 8. A multi-region ranging system based on chaotic polarization radar as claimed in claim 5, characterized in that the polarization controller segmentation module is also used to: The beam emitted by the distributed feedback laser passes through the optical isolator to generate a unidirectional propagation beam; The unidirectionally propagating light beam is divided by a polarization controller to generate polarized component light beams.