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CN-121831726-B - Motion compensation method and device for hovering unmanned aerial vehicle-mounted through-wall radar

CN121831726BCN 121831726 BCN121831726 BCN 121831726BCN-121831726-B

Abstract

The application provides a motion compensation method and equipment for a hovering unmanned aerial vehicle-mounted through-wall radar, which convert the problem of platform motion estimation into the problem of slope estimation in a frequency domain by excavating the inherent phase frequency linear characteristic of wall echo which is shown between the wall echo and each subcarrier under the motion of the platform, deduce a closed least square estimator to realize steady unbiased time delay estimation, and further complete the frequency domain compensation of full-band coherence. By compensation, the wall echo modulated by motion is converted from time-varying clutter to an approximately time-invariant background signal, so that the separability of phase modulation caused by weak respiration is effectively improved. The method does not need an additional sensor, does not limit the motion form of the platform, and avoids iterative optimization.

Inventors

  • YANG DEGUI
  • LI YUANFENG

Assignees

  • 中南大学

Dates

Publication Date
20260512
Application Date
20260313

Claims (9)

  1. 1. The motion compensation method for the hovering unmanned aerial vehicle-mounted through-wall radar is characterized by comprising the following steps of: step frequency echo signals of step frequency radar transmitting signals are obtained; Performing pulse compression on the step frequency echo signals to obtain step frequency echo data; Determining a wall body distance gate index corresponding to the wall body position according to the energy analysis of the step frequency echo data along the distance dimension; Determining a wall echo signal by the wall distance gate index; Performing frequency domain transformation on the wall echo signals to obtain complex frequency domain data of the wall echo signals on each frequency point; extracting complex phases of a linear representation from the complex frequency domain data; solving a phase-frequency domain optimization problem constructed for the complex phase to obtain a slope closed solution; determining a platform relative displacement estimated value by the slope closed-form solution, and Compensating the step frequency echo signal by using the platform relative displacement estimated value, Wherein the complex phase is expressed as: Wherein, the Representing complex phase, k being the frequency point, m being the time, b (m) being the slope, f being the frequency, Representing the phase of the noise and, And (3) with Independently, R wall0 is the nominal distance from the phase center of the unmanned aerial vehicle antenna to the plane of the wall, c is the speed of light, Is the platform relative displacement value at the mth moment, The phase-frequency domain optimization problem is expressed as: Solving the phase-frequency domain optimization problem, specifically: solving the phase-frequency domain optimization problem using a least squares estimation framework, Closed-form solution from the slope Determining platform relative displacement estimates The method specifically comprises the following steps: , and compensating the step frequency echo signal by using the platform relative displacement estimated value, wherein the step frequency echo signal comprises the following specific steps: And eliminating radial distance disturbance caused by projection of unmanned aerial vehicle-mounted jitter on a sight line in the step frequency echo signal by using the platform relative displacement estimated value.
  2. 2. The motion compensation method for a hovering unmanned airborne wall-penetrating radar according to claim 1, wherein pulse-compressing the step frequency echo signal comprises: The step frequency echo signal is repeatedly cycled in pulse at slow time Sampling and By means of And carrying out pulse compression on the step frequency pulse train by using the point fast discrete Fourier transform to obtain the step frequency echo data of each range gate.
  3. 3. The method for motion compensation of a hovering unmanned airborne wall penetrating radar according to claim 1, wherein determining a wall range gate index corresponding to a wall position based on energy analysis of the step frequency echo data along a distance dimension, specifically comprises: acquiring echo energy indexes of the step frequency echo data at each moment and each range gate; Carrying out slow time average on the echo energy index to obtain an average energy index; And determining the wall body distance door index from the average energy index.
  4. 4. The motion compensation method for hovering unmanned airborne wall penetrating radar according to claim 1, wherein the wall echo signal is determined by the wall range gate index, specifically: extracting corresponding step frequency echo data in the determined wall distance gate and the neighborhood range thereof based on the wall distance gate index, and And weighting the extracted step frequency echo data, and synthesizing to obtain the wall echo signal.
  5. 5. The method of motion compensation for a hovering unmanned airborne wall penetrating radar according to claim 1, wherein the step frequency echo signal is modeled by a wall echo term, a human echo term, and a noise term.
  6. 6. A method for detecting a target of a hovering unmanned aerial vehicle-oriented through-wall radar, wherein the method for detecting vital signs of the hovering unmanned aerial vehicle-oriented through-wall radar is based on the method for compensating for motion of the hovering unmanned aerial vehicle-oriented through-wall radar according to any one of claims 1 to 5, and the method for detecting vital signs of the hovering unmanned aerial vehicle-oriented through-wall radar comprises: performing pulse compression on the compensated step frequency echo signal to obtain range profile data, and And extracting the target signal from the range profile data.
  7. 7. The method for detecting the target of the hovering unmanned aerial vehicle-oriented through-the-wall radar according to claim 6, wherein extracting the target signal from the range profile data specifically comprises: Selecting a distance gate corresponding to the target position in a distance dimension according to the energy distribution characteristics of the target echo in the distance image data, extracting echo signals changing along with slow time at the distance gate corresponding to the target position to form a target slow time signal sequence, and And carrying out frequency domain analysis on the target slow time sequence to obtain the frequency spectrum characteristic of the target signal, wherein the frequency spectrum characteristic is used for representing the periodic inching characteristic of the target.
  8. 8. The method for target detection for hovering unmanned airborne wall-penetrating radar according to claim 7, wherein the frequency domain analysis is performed on the target slow time sequence, in particular by fourier transform, time-frequency analysis or equivalent frequency spectrum estimation methods.
  9. 9. An electronic device comprising a processor, and a memory coupled to the processor, The memory is used for storing a computer program; The processor is configured to execute the computer program stored in the memory, to cause the electronic device to perform the method of motion compensation for a hovering unmanned airborne wall-penetrating radar according to any of claims 1-5, or to perform the method of target detection for a hovering unmanned airborne wall-penetrating radar according to any of claims 6-8.

Description

Motion compensation method and device for hovering unmanned aerial vehicle-mounted through-wall radar Technical Field The application relates to the technical field of data processing, in particular to a motion compensation method, a target detection method and target detection equipment for a hovering unmanned aerial vehicle through-wall radar. Background The unmanned airborne through-the-wall radar expands the traditional close-range vital sign detection technology to the wide-area and high-altitude non-contact penetration sensing field, and provides a new technical means for disaster rescue, anti-terrorism actions, limited space situation sensing and other applications. Unlike ground-based fixed radars, unmanned aerial vehicles are subject to airflow disturbances in flight, and their actual trajectories often deviate from a preset state. The original static wall echo is converted into time-varying strong clutter, and the platform motion is deeply coupled with the target vital sign, so that weak physiological modulation characteristics are covered, and the actual detection performance is severely restricted. How to effectively inhibit noise of a time-varying wall and realize reliable separation of vital sign signals and platform movement becomes a core problem to be solved urgently for application of the system to engineering. The hovering unmanned aerial vehicle through-wall radar provides a feasible means for medium shielding and non-contact vital sign sensing in a limited space. However, under practical conditions, the platform disturbance can cause the wall echo to show strong time variability and be coupled with weak vital sign phase modulation depth, so that the through-wall radar system faces serious challenges in motion compensation and signal separation. Existing unmanned aerial vehicle through-the-wall radar systems can be broadly divided into a synthetic aperture radar mode and a hover mode. Compared with a synthetic aperture radar mode, the hovering unmanned aerial vehicle through-wall radar can realize coherent observation under a fixed geometric configuration without accurate aperture synthesis, so that the hovering unmanned aerial vehicle through-wall radar has better robustness to platform movement and higher detection sensitivity to weak vital sign signals. Based on the target detection technology of the unmanned aerial vehicle through-wall radar, a double radar scheme is proposed, platform motion is separated by subtracting a reference signal from ground reflection echo, but the requirement of the method on radar strict isolation and beam separation limits practical applicability, in addition, a radar self-motion offset method based on static obstacle reflection and a motion compensation method combining inter-frame cross correlation and distance unit alignment are also researched, however, performance of the method is reduced under strong clutter, low signal-to-noise ratio conditions or continuous time delay change and frequency related phase error, and recently, a motion compensation frame customized for a rotary unmanned aerial vehicle radar system is reported, but a signal model and a compensation strategy of the method are not directly suitable for a hovering unmanned aerial vehicle through-wall radar configuration with a fixed visual angle. Disclosure of Invention The application provides a motion compensation method, a target detection method and target detection equipment for a hovering unmanned aerial vehicle-mounted through-wall radar, which can solve one of the problems in the background technology. In order to achieve the above purpose, the application adopts the following technical scheme: in a first aspect, a motion compensation method for a hovering unmanned aerial vehicle-oriented through-the-wall radar is provided, including: step frequency echo signals of step frequency radar transmitting signals are obtained; Performing pulse compression on the step frequency echo signals to obtain step frequency echo data; Determining a wall body distance gate index corresponding to the wall body position according to the energy analysis of the step frequency echo data along the distance dimension; Determining a wall echo signal by the wall distance gate index; Performing frequency domain transformation on the wall echo signals to obtain complex frequency domain data of the wall echo signals on each frequency point; extracting complex phases of a linear representation from the complex frequency domain data; solving a phase-frequency domain optimization problem constructed for the complex phase to obtain a slope closed solution; Determining a platform relative displacement estimated value by the slope closed solution; And compensating the step frequency echo signal by utilizing the platform relative displacement estimated value. Based on the technical scheme, the problem of platform motion estimation is converted into the problem of slope estimation in a frequency domain by excavating