Dynamic positioning method, device, system and computer readable storage medium
Technical Field
The present invention relates to the field of radar technologies, and in particular, to a dynamic positioning method, device, system, and computer scale storage medium.
Background
In industrial application scenes, radar is utilized for monitoring and can be used as an effective quality monitoring and safety monitoring means, particularly in the aerospace field, technicians often need to dynamically position a dynamic target, but the effect of various schemes in the prior art cannot achieve millimeter wave level positioning precision yet, and a positioning system is complex in design, large in algorithm operation amount and high in system delay.
The paper published in IEEE at 3/15/2020 is named: the millimeter wave precision phase modulation radar (Micrometer Accuracy Phase Modulated Radar for Distance Measurement and Monitoring) for distance measurement and monitoring proposes a random binary phase modulation radar with improved precision, paper address: https:// ieeeExplore. Ieeee. Org/document/8911417, the scheme of which can be used for high-precision monitoring in the manufacturing industry, the radar system of which can be used in multi-user scenarios without occupying more bandwidth, compared to conventional high-precision radars using frequency modulated continuous waves (FMCW, frequency Modulated Continuous Wave), introduces a two-step range estimation method to estimate range, first, reduces the range estimation precision to half-wave wavelength by analyzing the envelope of the phase modulated signal; the carrier phase information then improves the range accuracy to several micrometers, and an equalization method is introduced to solve the problem of I/Q imbalance, and the radar system proposed in the paper is demonstrated under the carrier frequency of 80 GHz and the bandwidth of 2 GHz, the measured range error is within +/-7 micrometers, and in addition, the high measurement repetition rate of 500 and kHz is achieved, so that the radar system is suitable for real-time monitoring in automatic manufacturing. The solution of the paper still cannot effectively solve the problem of dynamic positioning in a dynamic target scene.
In the prior art, an imaging radar is also adopted to analyze and image the target of a target field by utilizing a multi-antenna technology, so that image positioning is realized, but under the complex condition of multiple targets, false images can be caused by background reflection, so that the imaging quality is affected, the target detection difficulty is improved, and in addition, the imaging radar has higher hardware cost and signal processing difficulty because of adopting a multi-antenna system.
Therefore, it is necessary to develop a dynamic positioning method and device for dynamic targets in order to overcome the shortcomings of the prior art.
Disclosure of Invention
The invention provides a dynamic positioning method and device of a dynamic target and a computer readable storage medium, and the technical scheme is as follows:
in a first aspect, the present invention provides a dynamic positioning method, including a processor, including the steps of:
An active tag and a receiver are arranged;
The active tag emits a signal;
a plurality of receivers receiving signals;
The multiple receivers divide the signals into a first signal and a second signal through the power divider respectively, the first signal directly enters the mixer, and the second signal enters the mixer after being delayed by the delay device;
the mixer processes the first signal and the second signal and then outputs a digital sampling signal;
The processor locates the dynamic target based on the digital sampled signal.
Further, the number of the receivers is at least one.
Further, the power divider can also be a coupler, and the delay device and the coupler are designed jointly.
Further, the active tag is an FMCW swept-frequency radar.
Further, the working frequency of the FMCW sweep radar is 76.5 GHz-77.5 GHz.
Further, the receiver is a millimeter wave receiver.
In a second aspect, the present invention provides a dynamic positioning device, including a transmitting end and a receiving end, where the transmitting end is an active tag, the receiving end is a millimeter wave receiver, and the receiving end performs target positioning by adopting the dynamic positioning method according to any one of the first aspects after receiving a signal transmitted by the transmitting end.
Further, the active tag is an FMCW swept-frequency radar.
Further, the working frequency of the FMCW sweep radar is 76.5 GHz-77.5 GHz.
Further, the millimeter wave receiver is composed of an antenna, a power divider, a time delay device, a mixer, a low-pass filter and a DSP, wherein the antenna receives signals of an active tag and then divides the signals into a first signal and a second signal through the power divider, the first signal is directly output to the mixer, the second signal enters the time delay device and then enters the mixer after time delay tau, the mixer generates quadrature IQ baseband signals, the quadrature IQ baseband signals enter the DSP after being smoothed by the low-pass filter, and the baseband signals are sampled into digital signals.
Further, the power divider can also be a coupler, and the delay device and the coupler are designed jointly.
In a third aspect, the present invention provides a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the dynamic positioning method according to any of the first aspects.
In a fourth aspect, the present invention provides a dynamic positioning system comprising:
One or more processors;
a memory; and
One or more computer programs, wherein the one or more computer programs are stored in the memory and configured to be executed by the one or more processors, which when executing the computer programs implement the steps of the dynamic positioning method according to any of the first aspects.
The method uses the sweep frequency radar as an active tag to calibrate a target point to be observed, uses a time delay millimeter wave receiver and digital processing to track and observe the moving position of the active tag, uses a plurality of receivers to observe at different angles, and further uses a triangular relation to perform three-dimensional space positioning on the active tag.
The invention uses the common FMCW radar as the active tag to be arranged on the interest point of the target, and uses a plurality of receivers to analyze the signals of the active tag, thereby realizing the accurate position tracking aiming at the fixed point of the target, effectively avoiding the problem of the migration of the radar echo reflection point and realizing the point positioning aiming at the target.
Drawings
Fig. 1: dynamic object recognition schematic of the prior art.
Fig. 2: radar echo schematic of prior art solutions.
Fig. 3: the system architecture of the positioning device of the invention is shown.
Fig. 4: the radar processing time sequence principle schematic diagram of the positioning device is shown in the specification.
Fig. 5: the radar sweep waveform diagram of the positioning device of the invention.
Fig. 6: the multi-receiver system architecture of the positioning device of the present invention.
Fig. 7: the positioning device of the invention forms a block diagram.
Fig. 8: the positioning method of the invention is a flow chart.
Detailed Description
Referring to the dynamic target recognition schematic diagram in the prior art shown in fig. 1, the imaging radar uses a multi-antenna technology to analyze and image the target of the target field, so as to realize image positioning, and in the complex multi-target situation shown in fig. 1, background reflection can cause false images, thereby affecting imaging quality and improving target detection difficulty.
The invention takes safety monitoring for the power generation windmill as an example, the radar does not need to completely image the windmill, and because the radar can accurately detect the distance and the position of key identification points such as the windmill blade, the windmill tower body and the like, the radar can analyze key indexes such as the swing of the windmill, the deformation of the blade, the settlement of the tower body and the like.
Although the imaging radar can monitor the windmill to a certain extent, the effective micron-level accuracy position information cannot be ensured because the relative positions of the windmill and the radar change, and the actual radar echo reflection points actually correspond to points of different positions of the windmill blade at different moments.
Referring to the radar echo schematic diagram of the prior art scheme of fig. 2, when radar waves irradiate on a windmill, a plurality of reflection loops are formed on the windmill blades, the reflection loops continuously change along with the rotation of the blades, so that the distance of reflection points detected by the radar also changes along with the loops to generate position drift, and the accuracy of target positioning is affected.
Referring to fig. 3, the system architecture diagram of the technical scheme of the invention sets a transmitting end on the windmill, preferably, the transmitting end is an active tag 10, the active tag 10 changes the reflected wave of the radar signal of the traditional positioning system into a signal transmitted from the active tag 10 and is transmitted in a single direction by a receiver, thereby avoiding the problem of multi-path uncertainty and solving the problem of fixing the detection point of the windmill relative to the windmill.
Preferably, the active tag 10 according to the present embodiment is a FMCW swept radar, and the present embodiment uses only the swept output end of the FMCW swept radar, and the receiving end is formed by a millimeter wave type receiver 20, where the receiver 20 is formed by an antenna 201, a power divider or coupler (not shown in the figure), shi Yanqi, 202, a mixer 203, a low-pass filter 204, and a DSP (digital signal processor) 205. The antenna 201 receives the signal of the active tag 10, and then divides the signal into a first signal and a second signal through a power divider or a coupler, the first signal is directly output to the mixer 203, the second signal enters the delay 202 and then enters the mixer 203 after passing through the delay τ, the quadrature IQ baseband signal generated by the mixer 203 represents the phase difference input by the mixer 203, and after being smoothed through the low-pass filter 204, the quadrature IQ baseband signal enters the DSP205, and the baseband signal is sampled into a digital signal for processing.
Those skilled in the art will appreciate that the delay unit 202 may be designed in combination with a coupler (not shown) to achieve signal decomposition and delay, so as to achieve the purpose of dynamic positioning of the present invention, which is not described herein.
The receiver 20 determines the position based on the phase difference between the waveforms of each frequency sweep and the last frequency sweep, and since the fixed time delay τ is equal to the frequency sweep interval at the receiving end, the repetition time of the waveform is τ correspondingly, so that the waveforms at each frequency mixer should be aligned in equal phase.
Fig. 4 is a schematic diagram of the radar processing timing sequence principle according to the technical scheme of the present invention, when a target moves, because the additional delay τ 1 is caused after the active tag 10 moves, two continuous sweep waveforms received by the receiver 20 are no longer aligned completely, a baseband waveform output is generated in a sweep interval generated by the movement of the target, the displacement of the target can be estimated through the baseband waveform output, once the movement of the target is finished, the waveforms are aligned again automatically, and in the alignment case, the baseband output is only a constant dc level.
Referring to fig. 5, according to the radar sweep waveform diagram of the present invention, the position estimation of the target tag can be obtained according to a formula based on the signal output by the baseband, for example, as follows: if the sweep frequency of the sweep radar starts from 76.5GHz to 77.5GHz, the silence time is 10ms, and the sweep time is 50ms, a signal S (t) of time t is obtained, and the signal S (t) is expressed by a formula (one):
(one),
Wherein k is a positive integer, j is an imaginary operator, f1 is a starting frequency, k is a frequency sweep number, t1 is a frequency sweep starting time point, t2 is a frequency sweep ending starting point,Is the sweep rate. When the target moves a distance d, an additional delay τ1=d/c is generated, where c is the speed of light, and the delayed signal is denoted s' (t), resulting in equation (two):
(II),
ComparisonAnd S (t), after the signals are mixed and low-pass filtered, the baseband IQ complex signals with phase difference are expressed as a formula (III):
(III) a third step;
After digitally sampling S BB (t), where fatf is the known sweep frequency rate, the unknown displacement τ1 is obtained using equations (one) and (two) because the baseband signal is only at And S (t) is generated in the staggered time, and under the condition that the moving speed of the target is not high, the displacement of the baseband signal can be accumulated each time, so that the moving path of the target can be tracked.
Referring further to fig. 6, in the multi-receiver system architecture diagram of the present invention, distances of the same active tag 10 are measured at different angles by a plurality of receivers Rx1, rx2 and Rx3, and then three-dimensional positioning is performed on the active tag 10 by a triangular relationship.
Referring to fig. 7, a block diagram of a positioning device according to the present invention, the positioning device includes a positioning device 100, a memory 101 and a processor 102, and it will be understood by those skilled in the art that all or part of the steps in the method for positioning a target in the above embodiment may be implemented by a program, where the program may be stored in a computer readable storage medium, and the memory includes: read Only Memory (ROM), random access Memory (RAM, random Access Memory), magnetic or optical disk, and the like.
Referring to fig. 8, a flowchart of a positioning method of the present invention includes the following steps:
step 301: the method comprises the steps of providing an active tag and at least one receiver; step 302: an active tag, which may be, for example, an FMCW swept frequency radar, emits a signal; step 303: the multiple receivers receive the signals, and then step 304 the multiple receivers divide the signals into a first signal and a second signal through a power divider or a coupler respectively, the first signal directly enters a mixer, and the second signal enters the mixer after being delayed by a delay device; step 305: the mixer processes the first signal and the second signal and then outputs a digital sampling signal; step 306: the processor locates the dynamic target based on the digital sampled signal.
The method uses the sweep frequency radar as an active tag to calibrate a target point to be observed, uses a time delay millimeter wave receiver and digital processing to track and observe the moving position of the active tag, uses a plurality of receivers to observe at different angles, and further uses a triangular relation to perform three-dimensional space positioning on the active tag.
The invention uses the common FMCW radar as the active tag to be arranged on the interest point of the target, and uses a plurality of receivers to analyze the signals of the active tag, thereby realizing the accurate position tracking aiming at the fixed point of the target, effectively avoiding the problem of the migration of the radar echo reflection point and realizing the point positioning aiming at the target.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.