High-speed terahertz radar rough velocity inversion and fusion fine velocity estimation method and device

Abstract

The invention provides a method and device for high-speed terahertz radar rough velocity inversion and fusion fine velocity estimation, which comprises the following steps: each slow-time signal corresponding to an acquired full-aperture terahertz echo signal is uniformly divided into sub-aperture signals in the distance direction; each sub-aperture signal is subjected to distance pulse compression processing to obtain sub-aperture pulse compression signals, which is the total number of slow-time signals; sub-aperture pulse compression signal samples are screened out from the sub-aperture pulse compression signals; a rough velocity is determined according to each sub-aperture pulse compression signal sample; a rough velocity error is compensated for a full-aperture terahertz echo signal to obtain a rough velocity error compensated signal, and a distance differential velocity is determined according to the compensated signal; the full-aperture terahertz echo signal is compensated to obtain a secondary velocity compensated signal; an envelope error velocity and a Doppler velocity are determined according to the secondary velocity compensated signal; and the radar's fine velocity is estimated according to the distance differential velocity, the envelope error velocity and the Doppler velocity, thereby improving the estimation accuracy.

Description

Technical Field

[0001] The present invention relates to the field of radar technology, and in particular to a method and device for high-speed terahertz radar rough velocity inversion and fusion fine velocity estimation. Background Art

[0002] The one-dimensional range image of the target is widely used in the radar field because of its characteristics of reflecting the target information concisely and intuitively. When the radar moves towards the target at a relatively high speed, in order to obtain an accurate one-dimensional range image of the target, it is necessary to estimate the relative speed information between the high-speed radar and the target from the echo signal, and then perform motion error compensation. When the relative speed between the high-speed radar and the target is much higher than the maximum unambiguous speed, the speed ambiguity number and speed estimation error obtained by the Doppler speed measurement method are large, so the Doppler speed measurement method is rarely used directly in high-speed radars.

[0003] The velocity estimation method based on quadratic fitting of motion trajectory of demultiplexing frequency modulation is a traditional high-speed radar velocity estimation method. However, the fitting of motion trajectory in this method relies on the measurement of demultiplexing frequency modulation reference distance by narrowband ranging signal. At this time, the system needs to be equipped with at least two types of signals. Under the high carrier frequency and large bandwidth terahertz radar system, the complexity of the system will be increased. In addition, the motion parameter estimation accuracy of this method relies on a high number of accumulated pulses. For high carrier frequency terahertz radar, it is necessary to accumulate tens of thousands of pulses to achieve high-precision motion parameter estimation. It is difficult for the system to process such a large amount of data. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a method and device for high-speed terahertz radar coarse velocity inversion and fusion fine velocity estimation, which specifically includes:

[0005] In a first aspect, the present invention provides a method for high-speed terahertz radar rough velocity inversion and fusion fine velocity estimation, comprising:

[0006] Each slow-time signal corresponding to the full-aperture terahertz echo signal is evenly divided into sub-aperture signals. Slow time is the azimuth sampling time, slow time signal is the signal corresponding to the azimuth sampling time, and the number of accumulated slow time signals is hereinafter referred to as the accumulated pulse number. is a positive integer greater than or equal to 1;

[0007] Perform range pulse compression processing on each sub-aperture signal to obtain sub-aperture pulse pressure signals, where M represents the total number of slow-time signals contained in the full-aperture terahertz echo signal;

[0008] According to the peak energy of the pulse pressure signal of each sub-aperture, From the sub-aperture pulse pressure signals, a plurality of sub-aperture pulse pressure signal samples are screened out;

[0009] Calculate the rough distance curve and rough velocity according to the pulse pressure signal samples of each sub-aperture;

[0010] According to the coarse velocity, the coarse velocity error compensation function constructed in advance is used to perform coarse velocity error compensation on the full aperture terahertz echo signal to obtain a coarse velocity error compensated signal;

[0011] Calculate the distance differential speed based on the signal after the coarse speed error compensation;

[0012] According to the distance differential velocity, the full-aperture terahertz echo signal is compensated by a pre-constructed quadratic velocity compensation function to obtain a quadratic velocity compensated signal;

[0013] Based on the envelope alignment method, the envelope error velocity and Doppler velocity are determined according to the signal after secondary velocity compensation;

[0014] The precise velocity of the radar is estimated based on the range differential velocity, envelope error velocity and Doppler velocity.

[0015] In a second aspect, the present invention further provides an electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0016] Memory, used to store computer programs;

[0017] The processor is used to implement any method provided in the first aspect when executing a program stored in the memory.

[0018] Beneficial effects of the present invention:

[0019] The high-speed terahertz radar rough velocity inversion and fusion fine velocity estimation method and device provided by the present invention divides each slow-time signal corresponding to the acquired full-aperture terahertz echo signal into sub-aperture signals, the slow time is the azimuth sampling time, and the slow time signal is the signal corresponding to the azimuth sampling time. is a positive integer greater than or equal to 1; performing range pulse compression processing on each sub-aperture signal to obtain each sub-aperture pulse compression signal; screening out multiple sub-aperture pulse compression signal samples from each sub-aperture pulse compression signal according to the peak energy of each sub-aperture pulse compression signal; determining a coarse velocity according to each sub-aperture pulse compression signal sample; constructing a coarse velocity error compensation function according to the coarse velocity; performing coarse velocity error compensation on the full-aperture terahertz echo signal through the coarse velocity error compensation function to obtain a coarse velocity error compensated signal; determining a range differential velocity according to the coarse velocity error compensated signal; constructing a secondary velocity compensation function according to the range differential velocity; compensating the full-aperture terahertz echo signal through the secondary velocity compensation function to obtain a secondary velocity compensated signal; determining an envelope error velocity and a Doppler velocity according to the secondary velocity compensated signal based on an envelope alignment method; estimating the precise velocity of a high-speed terahertz radar according to the range differential velocity, the envelope error velocity and the Doppler velocity. Through this method, the complexity of the radar system and the number of accumulated pulses required for speed estimation can be effectively reduced, breaking through the limitation of the number of accumulated pulses required for speed estimation and improving the accuracy of speed estimation.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a flow chart of a high-speed terahertz radar speed estimation method provided by the present invention;

[0022] Figure 2 A schematic diagram of a rough distance curve provided by the present invention;

[0023] FIG3( a ) is a schematic diagram of a pulse pressure result after coarse velocity error compensation provided by the present invention;

[0024] FIG3( b ) is a schematic diagram of a one-dimensional range image at a certain moment after coarse velocity error compensation provided by the present invention;

[0025] Figure 4 A schematic diagram of a precise speed error estimation provided by the present invention;

[0026] FIG5( a ) is a schematic diagram of a precision speed error compensation result provided by the present invention;

[0027] FIG5( b ) is a schematic diagram of a one-dimensional range image at a certain moment after precise velocity error compensation provided by the present invention;

[0028] FIG5(c) is a schematic diagram of a pulse distance motion correction result provided by the present invention;

[0029] FIG5(d) is a schematic diagram of a one-dimensional range image of a target after inter-pulse range motion correction provided by the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0031] The one-dimensional range image of the target is widely used in the radar field because it reflects the target information concisely and intuitively. To obtain the one-dimensional range image of the target, it is first necessary to obtain the accurate relative speed information between the radar and the target, and then perform motion error compensation. Under the traditional radar "one step and one stop" echo model, the echo can be directly processed using the range pulse compression technology, and then the speed information can be further calculated through signal processing. Assuming that the target is stationary, when the radar moves toward the target, the speed When the following formula is met:

[0032] ,

[0033] in, is the speed of light, is the radar signal bandwidth, is the pulse repetition time. At this time, the relative motion distance between the radar and the target within a single pulse repetition time is less than one radar range resolution unit, which can obtain a more accurate estimated speed and an accurate one-dimensional range image of the target.

[0034] However, with the development of radar technology, the requirements for radar range resolution are getting higher and higher, and the demand for broadband radars is also increasing. For broadband radars with bandwidths of hundreds of megabytes or more, if the above formula is to be satisfied, the radar speed must be reduced to the order of hundreds of meters per second or even lower. For high-speed radars, the "one step and one stop" echo model condition no longer holds. If the echo is directly subjected to range pulse compression, the echo signal cannot be fully coherently accumulated after processing, and one-dimensional image range broadening, range offset, envelope movement, and expansion and contraction will occur. Effective speed information cannot be obtained through this method. Therefore, it is necessary to further study the method of high-speed radar speed estimation.

[0035] The velocity estimation method based on quadratic fitting of motion trajectory of demultiplexing frequency modulation is an existing commonly used high-speed radar velocity estimation method. However, for high-speed terahertz radars with high carrier frequency, large bandwidth, and large pulse width, this method has the following disadvantages:

[0036] 1. Motion trajectory fitting depends on narrowband ranging signals.

[0037] This method requires first using a narrowband ranging signal to calculate the instantaneous reference distance, and then fitting the demultiplexing frequency modulation reference distance to obtain a rough radar motion trajectory curve, which contains initial distance information and speed information. For broadband radars, this method requires the system to be configured with at least two different types of signals, which increases the complexity of the system.

[0038] 2. The accuracy of motion parameter estimation depends on a higher number of accumulated pulses.

[0039] Accumulated pulse number Must meet:

[0040] ,

[0041] in, is the signal carrier frequency, is the signal frequency modulation slope, and the reference distance estimation error is , which can be expressed as ,in, For narrowband ranging signals, in a high signal-to-noise ratio environment The typical absolute value ranges from 1m to 10m. is the speed estimation error, which can be expressed as , is the pulse repetition time.

[0042] For high-speed terahertz radar, The range is 0.1THz~10THz. High carrier frequency may result in the number of accumulated pulses reaching tens of thousands, and the system is difficult to handle such a huge amount of data. When determining the target, reducing the number of accumulated pulses will inevitably lead to an increase in the velocity estimation error, and an accurate one-dimensional range image of the target cannot be obtained after compensation.

[0043] In view of the above problems, the present invention proposes a method for high-speed terahertz radar rough velocity inversion and fusion fine velocity estimation, which is a high-speed terahertz radar velocity estimation method based on sub-aperture rough velocity inversion and multi-characterization fusion fine estimation. The method introduces a strategy of dividing the full-aperture terahertz echo signal into multiple sub-aperture signals, inverts and estimates the rough velocity by linear regression fitting the sub-aperture rough distance curve, and estimates the distance differential velocity, envelope error velocity and Doppler velocity after compensating the rough velocity error of the full-aperture terahertz echo signal. The fine velocity is obtained by fusing the three and finely estimating, thereby realizing the accurate estimation of the relative velocity information between the high-speed terahertz radar and the target and the accurate acquisition of the target's one-dimensional range image.

[0044] The high-speed terahertz radar velocity estimation method provided by the present invention is described in detail below:

[0045] Figure 1 A schematic diagram of a high-speed terahertz radar velocity estimation method provided by the present invention is shown in FIG. Figure 1 As shown, the method includes:

[0046] S101, each slow-time signal corresponding to the acquired full-aperture terahertz echo signal is evenly divided into sub-aperture signal.

[0047] in, is a positive integer greater than or equal to 1, the slow time is the azimuth sampling time, and the slow time signal is the signal corresponding to the azimuth sampling time.

[0048] The full-aperture terahertz echo signal is the echo of the target scattering point. After passing through the radar receiver, it is conjugate-multiplied with the reference signal to perform a de-line frequency modulation operation to obtain the de-line frequency modulated terahertz echo signal.

[0049] Assume that the terahertz echo signal data matrix size is ,in is the number of distance sampling points corresponding to each slow-time signal, The number of accumulated pulses.

[0050] The radar signal is , the fast time (distance sampling time) is , the slow time (azimuth sampling time) is , the pulse repetition time is During the movement, the relative movement direction between the radar and the target scattering point and the beam irradiation direction remain unchanged. The instantaneous slant distance from the target scattering point to the radar is set to , the relative speed between the radar and the target scattering point is set to ,but After Taylor expansion, it can be expressed as: .

[0051] Optionally, the full-aperture terahertz echo signal can be expressed as:

[0052] ,

[0053] in,

[0054] ,

[0055] ,

[0056] ,

[0057] represents the fast time, i.e. the distance sampling time, represents the slow time, i.e. the azimuth sampling time, represents the backscattering coefficient of the target scattering point, represents a rectangular window, Indicates the instantaneous slant range from the target scattering point to the radar, represents the speed of light, Indicates the signal pulse width, represents the phase index, To indicate a plural unit, Indicates the signal carrier frequency, represents the frequency modulation slope, Indicates the reference distance of the de-interlacing frequency modulation. It represents the instantaneous slant distance from the target scattering point to the radar at the fast time zero. represents the relative speed between the radar and the target scattering point, , and is an intermediate variable.

[0058] Specifically, each slow-time signal corresponding to the acquired full-aperture terahertz echo signal is evenly divided into Sub-aperture signals, including: Terahertz echo signal for full aperture , each slow-time signal is evenly divided into The full-aperture terahertz echo signal is divided into Each sub-aperture signal contains The sub-aperture division needs to meet two conditions: each slow-time signal can be evenly divided in the range direction, and after the range pulse compression, an obvious one-dimensional range image of the sub-aperture target can be obtained.

[0059] For example, the radar imaging mode is the forward-looking mode, and the signal carrier frequency is , pulse repetition frequency , pulse accumulation time 0.02s, distance sampling points For example, the high-speed terahertz radar echo is taken as an example, when the relative height between the radar and the target is 250m, the slant distance from the center of the scene is 2000m, the target is stationary, and the radar has an upward speed of 2000m / s. , pulse accumulation time 0.02s, then the accumulated pulse number . Preset signal-to-noise ratio after coherent accumulation , each slow-time signal is divided into Sub-aperture signals are obtained, and a total of 64 sub-aperture pulse compression signal samples are obtained. Each signal sample contains 128 range sampling units, which meets the two conditions of sub-aperture division.

[0060] S102, perform range pulse compression processing on each sub-aperture signal to obtain Sub-aperture pulse pressure signal.

[0061] Wherein, M represents the total number of slow-time signals contained in the full-aperture terahertz echo signal.

[0062] Specifically, after the sub-apertures are divided, each sub-aperture signal is processed by Fast Fourier Transform (FFT) in the range direction to perform range pulse compression, and then coherent accumulation is performed to obtain each sub-aperture pulse compression signal.

[0063] S103, according to the peak energy of each sub-aperture pulse pressure signal, From the sub-aperture pulse pressure signals, multiple sub-aperture pulse pressure signal samples are screened out.

[0064] By screening samples of the pulse pressure signals of each sub-aperture, it is possible to ensure that the sample signals have high coherence.

[0065] In a possible implementation, a plurality of sub-aperture pulse compression signal samples are screened out from each sub-aperture pulse compression signal according to the peak energy of each sub-aperture pulse compression signal, including the following steps A1 and A2:

[0066] A1. Determine the highest value of the peak energy of each sub-aperture pulse compression signal, and determine the energy threshold according to the highest value and a preset signal-to-noise ratio after coherent accumulation.

[0067] The energy threshold is expressed as:

[0068] ,

[0069] in, represents the energy threshold, Represents the preset signal-to-noise ratio after coherent integration, Represents the highest value among the peak energies of the sub-aperture pulse compression signal.

[0070] A2. Determine whether the peak energy of each sub-aperture pulse compression signal is greater than an energy threshold, and determine the sub-aperture pulse compression signal with a peak energy greater than the energy threshold as a sub-aperture pulse compression signal sample.

[0071] Specifically, compare the peak energy and energy threshold of each sub-aperture pulse pressure signal , and the sub-aperture pulse compression signal with a peak energy greater than the energy threshold is determined as the sub-aperture pulse compression signal sample, which is expressed as:

[0072] ,

[0073] in, Indicates The peak energy of the sub-aperture pulse compression signal, Represents the energy threshold. When Keep the sample when The sample is discarded.

[0074] S104: Determine a rough velocity according to the pulse pressure signal samples of each sub-aperture.

[0075] Specifically, the sub-aperture distance sampling unit number at the signal peak of each sub-aperture pulse compression signal sample is calculated, the coarse distance at the signal peak of each sub-aperture pulse compression signal sample is estimated, and the estimated result is subjected to linear regression fitting to obtain a coarse distance curve; after obtaining the coarse distance curve, the slope of the coarse distance curve is calculated, and the coarse velocity value is obtained by inverting and estimating the slope of the coarse distance curve.

[0076] Optionally, determining the rough velocity according to the pulse pressure signal samples of each sub-aperture includes the following steps B1-B6:

[0077] B1. Determine the sub-aperture distance sampling unit number at the signal peak of each sub-aperture pulse pressure signal sample.

[0078] B2. Determine the sub-aperture signal sampling distance axis according to the sub-aperture distance sampling unit and the reference distance.

[0079] B3. Determine the coarse distance at the peak value of each sub-aperture pulse compression signal sample according to the sub-aperture distance sampling unit number at the signal peak value of each sub-aperture pulse compression signal sample and the sub-aperture signal sampling distance axis.

[0080] B4. Based on the linear regression fitting method, a rough distance curve is obtained according to the calculated rough distance.

[0081] B5. Determine the slope of the rough distance curve.

[0082] B6. The rough velocity is estimated by inverting the slope of the rough distance curve.

[0083] For example, assume that the full aperture distance sampling unit is ,in is the range sampling rate of the signal after demultiplexing, and the subaperture range sampling unit size can be expressed as .

[0084] When the full-aperture terahertz echo signal is close to the sampling rate , then the full aperture distance to the sampling unit size is calculated as , the sub-aperture distance is calculated to the sampling unit size , the preset reference distance for de-interlacing frequency modulation is , determine the sub-aperture signal sampling distance axis range :

[0085] ,

[0086] According to the sub-aperture distance sampling unit number and the sub-aperture signal sampling distance axis, the fitted rough distance curve is calculated as follows: Figure 2 The rough velocity is estimated by using the slope of the curve. .

[0087] S105 , according to the coarse velocity, using a pre-constructed coarse velocity error compensation function, performing coarse velocity error compensation on the full-aperture terahertz echo signal to obtain a coarse velocity error compensated signal.

[0088] Optional, coarse velocity error compensation function, expressed as:

[0089] ,

[0090] in,

[0091] ,

[0092] represents the frequency modulation slope, represents the rough speed, Indicates the signal carrier frequency, Indicates the preset reference distance for line decoupling and frequency modulation. represents the speed of light, represents the fast time, i.e. the distance sampling time, represents the slow time, i.e. the azimuth sampling time, is an intermediate variable.

[0093] Optionally, performing coarse velocity error compensation on the full-aperture terahertz echo signal by using a coarse velocity error compensation function to obtain a coarse velocity error compensated signal, including: multiplying the coarse velocity error compensation function by the full-aperture terahertz echo signal and then performing a distance-direction fast Fourier transform to obtain a coarse velocity error compensated signal, which is expressed as:

[0094] ,

[0095] in, represents the distance frequency of the signal, represents the fast Fourier transform, represents the full-aperture terahertz echo signal, represents the coarse velocity error compensation function, represents the fast time, i.e. the distance sampling time, Represents slow time, that is, azimuth sampling time.

[0096] The rough velocity estimated by the slope of the curve has a large error, as shown in Figure 3(a) and Figure 3(b). The rough velocity error compensation initially reduces the range image broadening phenomenon, but the target one-dimensional range image still has a slight range broadening. At the same time, errors such as range offset, envelope movement and shrinkage have not been corrected. Therefore, more precise velocity estimation and motion error compensation are needed.

[0097] S106: Determine the distance differential speed according to the signal after the coarse speed error compensation.

[0098] After the coarse velocity compensation, the coarse velocity error compensated signal is used to perform differential calculation through the distance information of the target one-dimensional range image of each adjacent slow-time signal to estimate the range differential velocity information.

[0099] Optionally, determining the distance differential speed according to the signal after the coarse speed error compensation includes the following steps C1-C3:

[0100] C1. Obtain the first and last two slow-time signals of the target one-dimensional range image in the signal after coarse velocity error compensation, and determine the time difference between signal pulses.

[0101] C2. Determine the full-aperture range sampling unit numbers of the target one-dimensional range images of the first and last slow-time signals.

[0102] C3. Determine the distance differential velocity according to the sampling unit number of each full-aperture distance and the time difference between signal pulses, expressed as:

[0103] ,

[0104] in, represents the distance differential velocity, To indicate the absolute value, and They represent the full aperture range sampling unit numbers of the target one-dimensional range images of the first and last slow-time signals, Indicates the time difference between signal pulses. Represents the full-aperture distance sampling unit.

[0105] S107 , according to the distance differential velocity, the full-aperture terahertz echo signal is compensated by a pre-constructed quadratic velocity compensation function to obtain a quadratic velocity compensated signal.

[0106] Optional, quadratic velocity compensation function, expressed as:

[0107] ,

[0108] in,

[0109] ,

[0110] Indicates the signal carrier frequency, represents the frequency modulation slope, Indicates the preset reference distance for line decoupling and frequency modulation. represents the speed of light, represents the distance differential velocity, represents the fast time, i.e. the distance sampling time, represents the slow time, i.e. the azimuth sampling time, is an intermediate variable.

[0111] Specifically, the quadratic velocity compensation function is combined with the full-aperture terahertz echo signal Multiply to get the signal after secondary speed compensation , expressed as:

[0112] .

[0113] S108. Based on the envelope alignment method, determine the envelope error velocity and the Doppler velocity according to the secondary velocity compensated signal.

[0114] Optionally, based on the envelope alignment method, the envelope error velocity and the Doppler velocity are determined according to the signal after secondary velocity compensation, including the following steps D1-D4:

[0115] D1. Perform envelope alignment operation on the signal after secondary velocity compensation to obtain the envelope aligned signal.

[0116] D2. Estimate the envelope distance based on the envelope aligned signal.

[0117] D3. According to the envelope distance, determine the envelope error speed, expressed as:

[0118] ,

[0119] in, represents the envelope error velocity, represents the envelope distance difference, , represents the envelope distance, Indicates the preset reference distance for line decoupling and frequency modulation. Indicates the time difference between signal pulses.

[0120] D4. Perform azimuth pulse compression processing on the envelope aligned signal through fast Fourier transform, and determine the Doppler unit number of the signal peak of the azimuth pulse compression result, and determine the Doppler velocity according to the Doppler unit number of the signal peak, which is expressed as:

[0121] ,

[0122] in, represents the Doppler velocity, The Doppler cell number representing the signal peak, represents the speed of light, Indicates the signal carrier frequency, To accumulate the number of pulses, Indicates the pulse repetition frequency.

[0123] S109. Estimate the precise velocity of the radar according to the range differential velocity, the envelope error velocity and the Doppler velocity.

[0124] The precise speed of the radar is the more accurate speed corresponding to the radar platform.

[0125] Specifically, the speed is determined by distance differential , envelope error speed , Doppler velocity The triple representation velocity fusion estimation is used to obtain the precise velocity , expressed as:

[0126] .

[0127] Exemplarily, based on the specific example shown in the detailed description of S104, the precise velocity can be estimated to be: , the precision velocity estimation error is .like Figure 4 As shown in the figure, in the actual high-speed range of 1000m / s~2000m / s, the absolute value of the estimated precision velocity estimation error is less than 10m / s, and the resulting range migration is less than a full-aperture range sampling unit. , thereby achieving accurate estimation of the relative speed between the high-speed radar and the target.

[0128] Optionally, the method further includes: constructing a precise velocity error compensation function according to the precise velocity; compensating the full-aperture terahertz echo signal by means of the precise velocity error compensation function to obtain a precise velocity error compensation result; constructing a migration correction function or a Keystone transform according to the precise velocity, and using the constructed migration correction function or the Keystone transform to correct the pulse-to-pulse distance migration of the full-aperture terahertz echo signal to obtain a one-dimensional range image of the target.

[0129] Specifically, the precise velocity is estimated through the above steps. After that, the precision velocity error compensation function is constructed to compensate the full-aperture terahertz echo signal again, and the fine compensation of the echo range broadening, range offset, envelope movement and shrinkage caused by high-speed radar motion errors is completed, and the coherent accumulation of the echo signal is realized. The precision velocity error compensation result and the one-dimensional range image of the target at a certain moment after the precision velocity error compensation are shown in Figure 5 (a) and Figure 5 (b), respectively. Finally, by constructing the range migration correction function or selecting the Keystone transformation method, the inter-pulse range migration is corrected to obtain an accurate one-dimensional range image of the target. The inter-pulse range migration correction result and the one-dimensional range image of the target after the inter-pulse range migration correction are shown in Figure 5 (c) and Figure 5 (d). Furthermore, the correction result can also be used for subsequent signal processing.

[0130] Compared with the prior art method that needs to use additional narrowband ranging signals to calculate the reference distance of the demultiplexing frequency modulation, the high-speed terahertz radar velocity estimation method provided by the present invention adopts a single broadband signal and introduces a strategy of dividing it into multiple sub-aperture signals in the distance direction, and then fits the sub-aperture coarse distance curve through linear regression, so as to estimate the coarse distance and coarse velocity parameters. The implementation method is relatively simple and can effectively reduce the complexity of the radar system. In addition, the present invention adopts a secondary velocity estimation strategy of sub-aperture coarse velocity inversion and multi-characterization fusion fine estimation, so that more accurate motion parameters can be estimated and an accurate one-dimensional range image of the target can be obtained by using echoes of fewer accumulated pulses. Compared with the prior art that needs to accumulate a certain number of Only a large number of pulses can achieve higher motion parameter estimation accuracy. In the high-carrier terahertz radar system, more than tens of thousands of pulses need to be accumulated. The method effectively reduces the burden of data processing and is more suitable for terahertz radar. Furthermore, the present invention calculates the coarse speed by coarse distance curve fitting, and estimates the distance characterization speed, envelope characterization speed and Doppler characterization speed information respectively after coarse speed error compensation to obtain the distance differential speed, envelope error speed and Doppler speed, and obtains the precise speed by fusing the three. The absolute value of the precise speed estimation error is less than 10m / s. When the radar moves at a high speed relative to the target and the same amount of data is processed, the present invention improves the speed estimation accuracy compared with the prior art.

[0131] The present invention also provides a structure of an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus.

[0132] Memory, used to store computer programs;

[0133] The processor is used to implement the steps provided in the above method embodiment when executing the program stored in the memory.

[0134] The communication interface is used for communication between the above electronic device and other devices.

[0135] The method provided in the embodiment of the present invention can be applied to electronic devices. Specifically, the electronic device can be: a desktop computer, a portable computer, an intelligent mobile terminal, a server, etc. This is not limited here, and any electronic device that can implement the present invention belongs to the protection scope of the present invention.

[0136] As for the electronic device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the specific contents and beneficial effects and other related matters can be referred to the partial description of the method embodiment.

[0137] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0138] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for high-speed terahertz radar rough velocity inversion and fusion fine velocity estimation, characterized in that: include: Each slow-time signal corresponding to the acquired full-aperture terahertz echo signal is evenly divided into sub-aperture signals, the slow time is the azimuth sampling time, and the slow time signal is the signal corresponding to the azimuth sampling time, is a positive integer greater than or equal to 1; Perform range pulse compression processing on each of the sub-aperture signals to obtain sub-aperture pulse pressure signals, where represents the total number of slow-time signals contained in the full-aperture terahertz echo signal; According to the peak energy of each sub-aperture pulse pressure signal, Filtering out a plurality of sub-aperture pulse pressure signal samples from the sub-aperture pulse pressure signals; Determining a rough velocity based on the pulse pressure signal samples of each of the sub-apertures; According to the rough velocity, the full-aperture terahertz echo signal is subjected to rough velocity error compensation by using a pre-constructed rough velocity error compensation function to obtain a rough velocity error compensated signal; Determining the distance differential speed according to the rough speed error compensated signal; According to the distance differential velocity, the full-aperture terahertz echo signal is compensated by a pre-constructed quadratic velocity compensation function to obtain a quadratic velocity compensated signal; Based on the envelope alignment method, the envelope error velocity and the Doppler velocity are determined according to the secondary velocity compensated signal; The accurate speed of the radar is estimated according to the range differential speed, the envelope error speed and the Doppler speed.

2. The method according to claim 1, characterized in that: Determining the rough velocity according to each of the sub-aperture pulse pressure signal samples includes: Determine the sub-aperture distance sampling unit number at the signal peak of each sub-aperture pulse pressure signal sample; Determining a coarse distance at a signal peak of each sub-aperture pulse compression signal sample according to the sub-aperture distance sampling unit number at a signal peak of each sub-aperture pulse compression signal sample; Based on a linear regression fitting method, a coarse distance curve is obtained according to the coarse distance at the signal peak of each sub-aperture pulse pressure signal sample; determining a slope of the coarse distance curve; The rough velocity is estimated by inversion through the slope of the rough distance curve.

3. The method according to claim 1 or 2, characterized in that: The full-aperture terahertz echo signal is expressed as: ， in, ， ， ， represents the fast time, i.e. the distance sampling time, represents the slow time, i.e. the azimuth sampling time, represents the backscattering coefficient of the target scattering point, represents a rectangular window, Indicates the instantaneous slant range from the target scattering point to the radar, represents the speed of light, Indicates the signal pulse width, represents the phase index, To indicate a plural unit, Indicates the signal carrier frequency, represents the frequency modulation slope, Indicates the reference distance of the de-interlacing frequency modulation. It represents the instantaneous slant distance from the target scattering point to the radar at the fast time zero. represents the relative speed between the radar and the target scattering point, , and is an intermediate variable.

4. The method according to claim 1 or 2, characterized in that: According to the peak energy of each sub-aperture pulse pressure signal, From the sub-aperture pulse pressure signals, a plurality of sub-aperture pulse pressure signal samples are screened out, including: The highest value of the peak energy of each sub-aperture pulse compression signal is determined, and the energy threshold is determined according to the highest value and a preset signal-to-noise ratio after coherent integration, which is expressed as: ， in, represents the energy threshold, Represents the preset signal-to-noise ratio after coherent integration, Represents the highest value among the peak energies of the sub-aperture pulse compression signal; It is determined whether the peak energy of each sub-aperture pulse compression signal is greater than the energy threshold, and the sub-aperture pulse compression signal with a peak energy greater than the energy threshold is determined as a sub-aperture pulse compression signal sample.

5. The method according to claim 1 or 2, characterized in that: The coarse speed error compensation function is expressed as: ， in, ， represents the phase index, To indicate a plural unit, represents the frequency modulation slope, represents the rough speed, Indicates the signal carrier frequency, Indicates the preset reference distance for line decoupling and frequency modulation. represents the speed of light, represents the fast time, i.e. the distance sampling time, represents the slow time, i.e. the azimuth sampling time, is an intermediate variable.

6. The method according to claim 1 or 2, characterized in that: The coarse velocity error compensation is performed on the full-aperture terahertz echo signal by using the coarse velocity error compensation function to obtain a coarse velocity error compensated signal, including: The coarse velocity error compensation function is multiplied by the full-aperture terahertz echo signal and then a distance-direction fast Fourier transform is performed to obtain the coarse velocity error compensated signal, which is expressed as: ， in, represents the distance frequency of the signal, represents the fast Fourier transform, represents the full-aperture terahertz echo signal, represents the coarse velocity error compensation function, represents the fast time, i.e. the distance sampling time, Represents slow time, that is, azimuth sampling time.

7. The method according to claim 1 or 2, characterized in that: Determining the distance differential speed according to the rough speed error compensated signal includes: Acquire the first and last two slow-time signals of the target one-dimensional range image in the signal after the coarse velocity error compensation, and determine the time difference between the signal pulses; Determine the full aperture range sampling unit numbers of the target one-dimensional range images of the first and last slow-time signals respectively; According to the number of each full-aperture distance sampling unit and the time difference between the signal pulses, the distance differential speed is determined, which is expressed as: ， in, represents the distance differential velocity, To indicate the absolute value, and They represent the full aperture range sampling unit numbers of the target one-dimensional range images of the first and last slow-time signals, Indicates the time difference between signal pulses. Represents the full-aperture distance sampling unit.

8. The method according to claim 1 or 2, characterized in that: The quadratic speed compensation function is expressed as: ， in, ， represents the phase index, To indicate a plural unit, Indicates the signal carrier frequency, represents the frequency modulation slope, Indicates the preset reference distance for line decoupling and frequency modulation. represents the speed of light, represents the distance differential velocity, represents the fast time, i.e. the distance sampling time, represents the slow time, i.e. the azimuth sampling time, is an intermediate variable.

9. The method according to claim 1 or 2, characterized in that: The envelope alignment method is based on the secondary velocity compensation signal to determine the envelope error velocity and the Doppler velocity, including: Performing an envelope alignment operation on the signal after secondary velocity compensation to obtain an envelope aligned signal; Estimate the envelope distance according to the envelope aligned signal; According to the envelope distance, the envelope error speed is determined, which is expressed as: ， in, represents the envelope error velocity, represents the envelope distance difference, , represents the envelope distance, Indicates the preset reference distance for line decoupling and frequency modulation. Indicates the time difference between signal pulses; The envelope aligned signal is processed by fast Fourier transform, and the Doppler unit number of the signal peak of the azimuth pulse compression result is determined, and the Doppler velocity is determined according to the Doppler unit number of the signal peak, which is expressed as: ， in, represents the Doppler velocity, The Doppler cell number representing the signal peak, represents the speed of light, Indicates the signal carrier frequency, Indicates the number of accumulated pulses. Indicates the pulse repetition frequency.

10. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, for implementing any of the methods described in claims 1-9 when executing a program stored in a memory.

Images