CN106707270A - Spinning object detection method based on vortex electromagnetic wave - Google Patents
Spinning object detection method based on vortex electromagnetic wave Download PDFInfo
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- CN106707270A CN106707270A CN201710128926.2A CN201710128926A CN106707270A CN 106707270 A CN106707270 A CN 106707270A CN 201710128926 A CN201710128926 A CN 201710128926A CN 106707270 A CN106707270 A CN 106707270A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/50—Systems of measurement based on relative movement of target
- G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
- G01S13/583—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
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Abstract
The invention provides a spinning object detection method based on vortex electromagnetic wave. According to the technical solution, the method comprises the following steps: 1, emitting vortex electromagnetic wave by using an antenna array; 2, receiving and processing echo signals to obtain a Doppler frequency offset; and 3, calculating object spinning angular velocity information by using a corresponding relation between the spinning Doppler frequency offset and the orbital angular momentum mode for emitting signals as well as the object spinning angular velocity. The method does not depend on radial motion between the object and a radar as required by traditional Doppler detection, can detect the spinning object under the foresight condition, and can provide a reference for object recognition and development of new system radar technologies.
Description
Technical field
The present invention relates to Radar Targets'Detection and identification technology field, more particularly to a kind of rotation based on vortex electromagnetic wave
Class object detection method.
Background technology
In recent years, municipal public safety receives more and more extensive concern, in particular with the popularization of small aircraft, city
City's low altitude safe is faced with increasing challenge.Meanwhile, the military requirement towards under current Information Condition, target identification exists
Military attack and defence etc. are played an important role in task, to the target of many rotation category features (such as helicopter, transporter
Deng) recognize there is urgent demand.
Vortex electromagnetic wave carries orbital angular momentum, phase front twist structure.Electromagnetic angular momentum can be divided into two
Individual part：Spin angular momentaum and orbital angular momentum.Wherein spin angular momentaum is relevant with polarization of electromagnetic wave, orbital angular momentum and light
Polarization, Wave-front phase it is relevant, be the important physical quantity for not yet being made full use of of electromagnetic wave one.Loaded when to electromagnetic wave
When orbital angular momentum is modulated, vortex electromagnetic wave will be formed, can thereon modulate required information, the information that improve electromagnetic wave is passed
Pass and acquisition capability, there are larger potentiality in the application field such as rolling target detection and target identification.
Existing rolling target detection technique mainly carries out target identification using the feature extraction of fine motion doppler information
(Target detection and feature extraction in indoor and outdoor environments
using micro-Doppler analysis[R].Ottawa:Defense Research and Development
Canada,2008).Translation between radar and target causes the rotation of translation Doppler, target will to cause Doppler frequency
Deflection, i.e. micro-Doppler effect.And work as radar line of sight radially without Doppler component or Doppler shift it is smaller in the case of
Almost cannot effective detection.Relative to conventional planar ripple, can be realized to many using the orbital angular momentum information of vortex electromagnetic wave
The high efficiency extraction of general Le information.Rolling target detection method based on vortex electromagnetic wave, is not required to rely on flat between radar and target
It is dynamic, it is possible to achieve to rotation doppler information, the high efficiency extraction of faint Doppler shift information, so as to realize rolling target
Detection.Existing detection method can find in optical field, see document Detection of a Spinning
Object Using Light's Orbital Angular Momentum[J].Martin P.J.Lavery et
al.Science 341,537,2013.But the rolling target detection method based on vortex electromagnetic wave not yet has money in microwave regime
Material can be looked into.
The content of the invention
The technical problem to be solved in the present invention is to realize rolling target using the vortex electromagnetic wave for carrying orbital angular momentum
Detection.
Basic thought of the invention as shown in figure 1, by launching vortex electromagnetic wave irradiation rolling target, to the target for receiving
Echo carries out treatment and obtains rotation Doppler shift information, and using orbital angular momentum state model, (state model is also referred to as and opens up
Flutter lotus number) and the corresponding relation between Doppler shift, target angular velocity of rotation Ω is rotated, obtain the anglec of rotation speed of target
Degree information.
Technical scheme is as shown in Fig. 2 specifically include following steps：
The first step, vortex electromagnetic wave is launched using aerial array.
N number of bay is evenly spaced on a circumference and forms uniform circular array；Apply signal to each bay to swash
Encourage, vortex electromagnetic wave is formed as transmission signal, wherein signal excitation is that frequency is identical, excitation amplitude is identical, initial phase
The position single-frequency constant amplitude relevant with bay orientation incrementally phase modulated signal.
Second step, receives and processes echo-signal.
Target echo is received using individual antenna, acquisition Doppler is processed using following any one mode to target echo
Frequency shift (FS)：1. the plant mode, and transmission signal is carried out into coherent mixing with the target echo for receiving, and obtains target rotation Doppler
Frequency shift (FS)；2. the plant mode, and phase changing capacity of the measurement target echo within a period of time obtains mesh by time derivation
The frequency of echo is marked, the frequency that the frequency subtracts transmission signal can obtain target rotation Doppler shift.
3rd step, calculates target angular velocity of rotation information.
Doppler shift is rotated based on the target that second step is obtained, is believed with transmitting using Doppler shift is rotated
Number orbital angular momentum pattern and target angular velocity of rotation between corresponding relation, calculate target angular velocity of rotation information, it is real
Now to the detection of rolling target.
Orbital angular momentum is carried the beneficial effects of the invention are as follows vortex electromagnetic wave, with spiral phase front, is improved
Modulates information dimension.The present invention carries out rolling target detection using vortex electromagnetic wave, in detection process, using track angular motion
Corresponding relation between amount pattern and target angular velocity of rotation, rotation Doppler shift, obtains the angular velocity of rotation of target
Information, detection process is simple, detection efficiency is high.Additionally, the method does not rely on target and the thunder that traditional Doppler's detection is required
Radial motion between reaching, can realize the detection to rolling target under the conditions of forward sight, can be target identification, new system radar
Technology development is offered reference.
Accompanying drawing (table) explanation
Fig. 1 is rolling target detection schematic diagram of a scenario of the present invention；
Fig. 2 is rolling target detection scheme schematic flow sheet of the present invention；
Fig. 3 is radar observation space coordinates；
Fig. 4 is target echo signal phase distribution when target angular velocity of rotation is 40 π rad/s；
Fig. 5 is target echo signal phase distribution when target angular velocity of rotation is 61.7 π rad/s.
Specific embodiment
With reference to specific embodiment, the present invention is described in detail.
The first step, N number of bay is equally spaced arranged on the circumference that a radius is a, forms emission array, right
Each bay applies signal excitation, forms vortex electromagnetic radiation signal, and wherein signal is actuated to single-frequency, constant amplitude, incrementally
Phase modulated signal.
The parameter selection of the bay number N and array radius a of uniform circular array is set according to actually detected demand, leads to
Often, accuracy of detection requirement is higher, and element number of array N is bigger, and a is bigger for array radius.
With emission array center as the origin of coordinates, aerial array is positioned over XOY plane, sets up radar observation space coordinates
It is XYZ, as shown in Figure 3.In Fig. 3, a bay is represented at the position where each dashed arrows, at origin of coordinates O
Reception antenna position is represented, uniformly to place N number of transmitting antenna array element, each array element sequence number is followed successively by 1,2 to circumference shown in dotted line,
3 ..., N, n-th transmitting antenna azimuth are 2 π n/N, wherein n=1,2 ..., N.
To transmitting antenna array element apply exciting signal frequency be f, excitation amplitude it is identical, incrementally phase-modulation when, i.e., n-th
Individual bay phase modulation is φnDuring=2 π nl/N, the vortex electromagnetic wave that orbital angular momentum pattern is l, wherein n can be produced
=1,2 ..., N, l are orbital angular momentum pattern (i.e. topological charge number).
Encouraged using above-mentioned array configuration and signal, uniform circular array can produce the vortex electromagnetism that orbital angular momentum pattern is l
Ripple.For radar observation coordinate system space any point P (r, θ, φ), its electric-field intensity Es(r, θ, φ l) are represented by
Wherein i is imaginary unit, and r, θ, φ are respectively distance, pitching, the azimuthal coordinates of arbitrfary point P, and k=2 π f/c are represented
The vortex electromagnetic wave wave number of transmitting, c is light spread speed, J in vacuuml() represents l rank Bessel function of the first kind.
Second step, encourages according to the array configuration described in the first step and signal, and it is f, track angle that uniform circular array produces frequency
The vortex electromagnetic wave beam irradiation target of momentum mode l, target echo, echo-signal E are received using individual antennar(r,θ,φ,
L) can be expressed as
Wherein σ (r, θ, φ) represents Target scatter section area, and Δ k=2 π Δs f/c draws for rotation Doppler shift Δ f
The wave-number migration for rising.
The target echo signal for receiving, can use two kinds of processing modes：
1. plant mode：By the way of transmission signal and the coherent mixing of reception signal, Doppler frequency is obtained in frequency domain
Skew.Coherent mixing on the target echo signal of reception i.e. to being multiplied by ei2krPhase term, obtains
From formula (3) as can be seen that after target echo signal is mixed through coherent, being extracted through frequency-domain frequency can be rotated
Doppler shift amount Δ f=Δ kc/2 π.
2. plant mode：Phase changing capacity of the measurement target echo signal within a period of time, obtains by time derivation
Obtain the frequency of target echo signalD Φ and dt represent that phase place change and corresponding observing time are long respectively
Degree, wherein required precision is higher, and observing time, dt was bigger.Target echo frequency f ' subtracts emission signal frequency f and is rotated
Doppler shift Δ f=f '-f.
3rd step, between rotation Doppler shift and the orbital angular momentum and target angular velocity of rotation of transmission signal
Corresponding relation meet
Wherein Δ f is that target rotates Doppler shift, and l is the orbital angular momentum pattern of transmission signal, and Ω represents mesh
Mark angular velocity of rotation.
The target obtained based on formula (4) and second step rotates Doppler shift amount Δ f, can obtain detected
The angular velocity of rotation Ω of target.
The present invention has passed through experimental verification.In experiment, setting emission signal frequency f=9.9GHz, vortex electromagnetism wave trajectory
Angular momentum pattern l=1, transmission signal vertical irradiation rolling target, in the absence of radial motion, many without translation between radar and target
General Le information；Target echo is received using individual antenna；Target angular velocity of rotation sets and is respectively 40 π rad/s and 61.7 π rad/
S, obtains the echo-signal phase distribution obtained after coherent mixing under different rotary angular speed successively, as shown in Figure 4 and Figure 5, its
Middle abscissa represents the sampling time, and ordinate is the phase at the moment；Extracted through frequency-domain frequency and can obtain corresponding Doppler frequently
Move side-play amount and be respectively Δ f=20Hz and Δ f=31.25Hz.Using rolling target detection method proposed by the invention, obtain
Target angular velocity of rotation under two kinds of scenes is respectively 40 π rad/s and 62.5 π rad/s.Result shows, inspection proposed by the present invention
Survey method can effectively realize the detection of target rotation Doppler and angular velocity of rotation.
Claims (1)
1. a kind of rolling target detection method based on vortex electromagnetic wave, it is characterised in that comprise the steps：
The first step, vortex electromagnetic wave is launched using aerial array：
N number of bay is evenly spaced on a circumference and forms uniform circular array；Apply signal excitation, shape to each bay
Into vortex electromagnetic wave as transmission signal, wherein signal excitation is identical frequency, identical excitation amplitude, initial phase and day
The linear array unit relevant single-frequency constant amplitude in orientation incrementally phase modulated signal；
Second step, receives and processes echo-signal：
Using individual antenna receive target echo, to target echo using following any one mode process acquisition target rotate it is many
General Le frequency shift (FS)：1. the plant mode, and transmission signal is carried out into coherent mixing with the target echo for receiving, and obtains target rotation many
General Le frequency shift (FS)；2. the plant mode, and phase changing capacity of the measurement target echo within a period of time is obtained by time derivation
The frequency of target echo is obtained, the frequency that the frequency subtracts transmission signal obtains target rotation Doppler shift；
3rd step, calculates target angular velocity of rotation information：
Using target rotation Doppler shift and transmission signal orbital angular momentum pattern and target angular velocity of rotation it
Between corresponding relation, calculate target angular velocity of rotation information.
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107290728A (en) * | 2017-06-09 | 2017-10-24 | 清华大学 | A kind of equivalent electromagnetic wave orbital angular momentum pulse radar detection method and system |
| CN107656253A (en) * | 2017-08-25 | 2018-02-02 | 北京航空航天大学 | Electromagnetism vortex Synthetic Aperture Radar Echo emulation mode and device |
| CN108287334A (en) * | 2018-02-06 | 2018-07-17 | 西安四方星途测控技术有限公司 | A kind of Spin Satellite Attitude method of estimation and system based on rcs measurement data |
| CN108572363A (en) * | 2018-04-27 | 2018-09-25 | 中国人民解放军国防科技大学 | Electromagnetic vortex high-resolution imaging method based on sparse Bayesian learning |
| CN108594198A (en) * | 2018-07-03 | 2018-09-28 | 中国人民解放军国防科技大学 | Composite moving target detection method based on orbital angular momentum |
| CN109541594A (en) * | 2018-11-12 | 2019-03-29 | 中国人民解放军国防科技大学 | Stripe SAR three-dimensional imaging method based on vortex electromagnetic waves |
| CN109856618A (en) * | 2018-12-04 | 2019-06-07 | 上海无线电设备研究所 | A kind of target angular velocity of rotation calculation method based on rolling target RCS feature |
| CN112114311A (en) * | 2020-08-21 | 2020-12-22 | 西安空间无线电技术研究所 | Nondestructive detection method based on terahertz vortex electromagnetic waves |
| CN112285730A (en) * | 2020-10-28 | 2021-01-29 | 哈尔滨工业大学 | Multi-dimensional information detection system based on orbital angular momentum modulation |
| CN112731433A (en) * | 2020-12-28 | 2021-04-30 | 中国人民解放军战略支援部队航天工程大学 | Target compound motion detection device based on dual-frequency stack state vortex optical rotation |
| CN112731367A (en) * | 2020-12-18 | 2021-04-30 | 桂林电子科技大学 | Rotor wing target characteristic analysis and extraction method based on vortex electromagnetic waves |
| CN112904346A (en) * | 2021-01-19 | 2021-06-04 | 鹏城实验室 | Rotating speed measuring method, device, equipment and storage medium |
| WO2022117019A1 (en) * | 2020-12-04 | 2022-06-09 | 华为技术有限公司 | Communication method and apparatus, and computer readable storage medium |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105676204A (en) * | 2016-01-25 | 2016-06-15 | 中国人民解放军国防科学技术大学 | Estimation method for rotation micro Doppler frequency based on radar HRRP (High Resolution Range Profile) |
-
2017
- 2017-03-06 CN CN201710128926.2A patent/CN106707270B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105676204A (en) * | 2016-01-25 | 2016-06-15 | 中国人民解放军国防科学技术大学 | Estimation method for rotation micro Doppler frequency based on radar HRRP (High Resolution Range Profile) |
Non-Patent Citations (3)
| Title |
|---|
| MARTIN P.J.LAVERY ET AL.: "Detection of a spinning object using light"s orbital angular momentum", 《SCIENCE》 * |
| MINGYANG ZHAO ET AL.: "Measurement of the rotational Doppler frequency shift of a spinning object using a radio frequency orbital angular momentum beam", 《OPTICS LETTERS》 * |
| 江月松: "《微多普勒效应及其应用》", 31 August 2013 * |
Cited By (22)
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|---|---|---|---|---|
| CN107290728A (en) * | 2017-06-09 | 2017-10-24 | 清华大学 | A kind of equivalent electromagnetic wave orbital angular momentum pulse radar detection method and system |
| CN107290728B (en) * | 2017-06-09 | 2020-07-10 | 清华大学 | Equivalent electromagnetic wave orbital angular momentum pulse radar detection method and system |
| CN107656253A (en) * | 2017-08-25 | 2018-02-02 | 北京航空航天大学 | Electromagnetism vortex Synthetic Aperture Radar Echo emulation mode and device |
| CN107656253B (en) * | 2017-08-25 | 2019-12-13 | 北京航空航天大学 | Electromagnetic vortex synthetic aperture radar echo signal simulation method and device |
| CN108287334A (en) * | 2018-02-06 | 2018-07-17 | 西安四方星途测控技术有限公司 | A kind of Spin Satellite Attitude method of estimation and system based on rcs measurement data |
| CN108572363A (en) * | 2018-04-27 | 2018-09-25 | 中国人民解放军国防科技大学 | Electromagnetic vortex high-resolution imaging method based on sparse Bayesian learning |
| CN108594198A (en) * | 2018-07-03 | 2018-09-28 | 中国人民解放军国防科技大学 | Composite moving target detection method based on orbital angular momentum |
| CN108594198B (en) * | 2018-07-03 | 2020-06-19 | 中国人民解放军国防科技大学 | Composite moving target detection method based on orbital angular momentum |
| CN109541594A (en) * | 2018-11-12 | 2019-03-29 | 中国人民解放军国防科技大学 | Stripe SAR three-dimensional imaging method based on vortex electromagnetic waves |
| CN109856618A (en) * | 2018-12-04 | 2019-06-07 | 上海无线电设备研究所 | A kind of target angular velocity of rotation calculation method based on rolling target RCS feature |
| CN112114311A (en) * | 2020-08-21 | 2020-12-22 | 西安空间无线电技术研究所 | Nondestructive detection method based on terahertz vortex electromagnetic waves |
| CN112114311B (en) * | 2020-08-21 | 2022-03-04 | 西安空间无线电技术研究所 | Nondestructive detection method based on terahertz vortex electromagnetic waves |
| CN112285730A (en) * | 2020-10-28 | 2021-01-29 | 哈尔滨工业大学 | Multi-dimensional information detection system based on orbital angular momentum modulation |
| CN112285730B (en) * | 2020-10-28 | 2023-10-20 | 哈尔滨工业大学 | Multidimensional information detection system based on orbital angular momentum modulation |
| WO2022117019A1 (en) * | 2020-12-04 | 2022-06-09 | 华为技术有限公司 | Communication method and apparatus, and computer readable storage medium |
| CN112731367A (en) * | 2020-12-18 | 2021-04-30 | 桂林电子科技大学 | Rotor wing target characteristic analysis and extraction method based on vortex electromagnetic waves |
| CN112731367B (en) * | 2020-12-18 | 2023-07-14 | 桂林电子科技大学 | Rotor wing target feature analysis and extraction method based on vortex electromagnetic waves |
| CN112731433A (en) * | 2020-12-28 | 2021-04-30 | 中国人民解放军战略支援部队航天工程大学 | Target compound motion detection device based on dual-frequency stack state vortex optical rotation |
| CN112731433B (en) * | 2020-12-28 | 2023-11-03 | 中国人民解放军战略支援部队航天工程大学 | Target compound motion detection device based on double-frequency superposition state vortex rotation |
| CN112904346A (en) * | 2021-01-19 | 2021-06-04 | 鹏城实验室 | Rotating speed measuring method, device, equipment and storage medium |
| WO2022155997A1 (en) * | 2021-01-19 | 2022-07-28 | 鹏城实验室 | Rotational speed measurement method, apparatus and device, and storage medium |
| CN112904346B (en) * | 2021-01-19 | 2024-01-23 | 鹏城实验室 | Rotational speed measuring method, rotational speed measuring device, rotational speed measuring equipment and storage medium |
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