KR102632928B1 - Target location determine apparatus using extrapolation and method thereof - Google Patents

Abstract

A target positioning device is disclosed. This target positioning device is a radar device that emits a radar signal and receives a received signal reflected by the target, separates a plurality of chirp signals included in the received signal, and uses the plurality of chirp signals It includes a processor that generates an extended reception signal and generates distance information between the target and the radar using the extended reception signal.

Description

Target location determination device and method using extrapolation {TARGET LOCATION DETERMINE APPARATUS USING EXTRAPOLATION AND METHOD THEREOF}

The present disclosure relates to a target positioning device and method using extrapolation, and specifically, to a radar detection device and method with improved accuracy and resolution even in a short detection time.

Doppler detection using radar is used in a variety of fields, including vehicle radar as well as biological signal detection. In a radar system, in order to estimate the target's moving speed, Doppler generated by the target's moving speed is estimated.

For Doppler estimation with high accuracy or high resolution, a large number of symbols are required. As such, Doppler detection performance in radar systems has a trade-off between detection time and accuracy/resolution.

If the detection time is insufficient, multiple targets with similar movement speeds or similar biometric information may be detected as one target. However, if multiple targets are distinguished as the detection time increases after being detected as one target, errors may occur due to target changes.

Therefore, a method was required to improve the resolution and accuracy of Doppler estimation even when detection time is insufficient.

Therefore, the purpose of the present disclosure is to provide a target positioning device and method using extrapolation with improved accuracy and resolution even in a short detection time.

A target positioning device according to the present disclosure for achieving the above object includes a radar device that emits a radar signal and receives a received signal reflected by the target, and a plurality of chirps included in the received received signal. It includes a processor that separates signals, generates an extended received signal using the plurality of chirp signals, and generates distance information between a target and a radar using the extended received signal.

In this case, the processor extends the chirp signal by pasting a certain section of symbols to the rear end of the chirp signal for each chirp signal composed of a plurality of symbols, and performs calculations between the corresponding symbols for each of the expanded plurality of chirp signals. By performing this, an extended reception signal can be generated.

In this case, the operation between the symbols may be a multiplication operation.

Meanwhile, the radar device may be a biological FMCW radar.

Meanwhile, a method for determining a target position according to an embodiment of the present disclosure includes receiving a received signal in which a radar signal output by a radar is reflected from the target, separating a plurality of chirp signals included in the received received signal. and generating an extended received signal using the plurality of chirp signals, and generating distance information between the target and the radar using the extended received signal.

In this case, the step of generating the extended received signal is to extend the chirp signal by pasting a symbol of a certain section to the rear end of the chirp signal for each chirp signal composed of a plurality of symbols, and to each of the expanded plurality of chirp signals. An extended received signal can be generated by performing operations between corresponding symbols.

In this case, the operation between the symbols may be a multiplication operation.

Meanwhile, in a computer-readable recording medium including a program for executing a method for determining a target position according to an embodiment of the present disclosure, the method for determining a target position is a received signal in which a radar signal output from a radar is reflected to the target. Receiving, separating a plurality of chirp signals included in the received reception signal, generating an extended reception signal using the plurality of chirp signals, and using the extended reception signal It includes generating distance information between the target and the radar.

As described above, according to various embodiments of the present disclosure, the received signal can be expanded through multiplication between symbols, thereby increasing the resolution of Doppler estimation.

1 is a diagram illustrating a specific configuration of a target positioning device according to an embodiment of the present disclosure;
Figure 2 is a diagram showing the specific configuration of the processor of Figure 1;
3 is a diagram showing an example of a radar signal transmitted and a reflected signal received by a biological radar according to an embodiment of the present disclosure;
4 is a diagram for explaining a Doppler estimation method according to an embodiment of the present disclosure;
5 is a diagram for explaining an extrapolation method according to an embodiment of the present disclosure, and
Figure 6 is a flowchart explaining a method for determining a target position according to an embodiment of the present disclosure.

Terms used in this specification will be briefly described, and the present disclosure will be described in detail.

The terms used in the embodiments of the present disclosure were selected from general terms that are currently widely used as much as possible while considering the functions in the present disclosure, but this may vary depending on the intention or precedent of a technician working in the art, the emergence of new technology, etc. . In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description part of the relevant disclosure. Therefore, the terms used in this disclosure should be defined based on the meaning of the term and the overall content of this disclosure, rather than simply the name of the term.

Embodiments of the present disclosure may be subject to various changes and may have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the scope to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the disclosed spirit and technical scope. In describing the embodiments, if it is determined that a detailed description of related known technology may obscure the point, the detailed description will be omitted.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. Terms are used only to distinguish one component from another.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, “comprises.” Or “made up.” Terms such as are intended to designate the presence of features, numbers, steps, operations, components, parts, or a combination thereof described in the specification, but are intended to indicate the presence of one or more other features, numbers, steps, operations, components, parts, or It should be understood that the existence or addition possibility of combinations of these is not excluded in advance.

In an embodiment of the present disclosure, a 'module' or 'unit' performs at least one function or operation, and may be implemented as hardware or software, or as a combination of hardware and software. Additionally, a plurality of 'modules' or a plurality of 'units' may be integrated into at least one module and implemented with at least one processor, except for 'modules' or 'units' that need to be implemented with specific hardware.

Below, with reference to the attached drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily practice them. However, the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present disclosure in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Hereinafter, the present disclosure will be described in more detail with reference to the drawings.

1 is a diagram illustrating a specific configuration of a target positioning device according to an embodiment of the present disclosure.

Referring to FIG. 1, the target position determination device 100 includes a radar device 110 and a processor 120. Here, the target positioning device 100 is a radar capable of emitting radar signals, a navigation device for autonomous driving, a hazard detection device that detects hazards while driving the vehicle, or a vehicle including these, or a biological signal (e.g., It may be a device for measuring a breathing signal or heart rate signal.

The radar device 110 emits a radar signal and receives a signal reflected from the target. This radar device 110 may use a phased array antenna. Here, a phased array antenna (or phased array system) is a large antenna that scans a radiation beam by electronically changing the phase fed to each element of the array antenna. In particular, such a radar device may be a device that operates in a Frequency Modulation Continuos Wave (FMCW) radar (eg, FMCW for living organisms or FMCW for vehicles).

Here, FMCW is a radar signal that is transmitted by modulating the frequency of a sine wave and reflected from the front. It is a system that can simultaneously measure the distance and speed of the target by using the time-frequency domain simultaneously. The FMCW radar method has very high bandwidth efficiency and low complexity, so it is widely used in automotive radar systems.

When operating in the FMCW radar method, the radar device 110 can generate and transmit a regular wave frequency-modulated with time through a waveform generator and a voltage-controlled oscillator. For example, the radar device 110 may create and transmit a transmission signal by modulating the preceding frequency by the frequency BW (Bandwidth) during △t.

The propagated signal is reflected by an object in front and can be received by the radar device 110 with a time delay depending on the distance and a Doppler frequency due to the speed difference. Here, the received radar signal can be multiplied by the received signal and the transmitted signal using a mixer, and the distance can be estimated based on the frequency difference between them. The received radar signal described later may be the radar signal itself received through an antenna, or may be a signal obtained by multiplying the received signal and the transmitted signal by a mixer as described above.

Additionally, the radar device 110 may perform analog-to-digital conversion on the received radar signal and provide the digitally converted radar signal to the processor 120. That is, the radar signal described later can be expressed as a digital value.

The processor 120 controls each component within the target position detection device 100. Specifically, the processor 120 controls the radar device 110 to emit a radar signal to detect objects in front of (or around) the device in real time, and uses the radar signal received from the radar device 110 to The target location can be detected through analysis.

And the processor 120 can predict the location of the target. Specifically, the processor 120 can predict the distance to the target and the angle of the target, respectively, and predict the location of the target using the predicted distance and angle.

Below, the operation of predicting the distance to the target will be described.

First, the processor 120 separates a plurality of chirp signals included in the received signal.

Then, the processor 120 generates an expanded received signal using a plurality of chirp signals. Specifically, the processor 120 extends the chirp signal by pasting a symbol of a certain section to the rear end of the chirp signal for each chirp signal composed of a plurality of symbols, and performs an operation between the corresponding symbols for each of the expanded plurality of chirp signals. You can generate an extended reception signal by performing . Here, the operation between symbols may be a multiplication operation. Details of this extrapolation method are described later in FIG. 5.

And the processor 120 generates distance information between the target and the radar using the extended received signal.

Additionally, the processor 120 can predict the angle of the target by performing Discrete Fourier Transform (DFT) on radar signals received through a plurality of channels. At this time, the processor 120 can determine the location of the target by applying the radar signal of the radar channel to a high-resolution algorithm.

Here, the high-resolution algorithm (or super-resolution algorithm) may be a multiple signal classification algorithm (MUSIC), and when implemented, ESPRIT (estimation of signal parameters via rotational invariance techniques) or other high-resolution frequency detection algorithms may be used. It may be possible.

As described above, the target positioning device according to the present disclosure detects the distance by expanding each of a plurality of chirp signals using an extrapolation method, so that Doppler estimation is possible with high resolution even when the detection time is short.

In showing and describing FIG. 1, the target detection device is shown and described as including only two components, but may further include other components when implemented. For example, it may further include a communication device for transmitting the detected target location to another device or a display for displaying the detected target location.

In addition, in showing and describing FIG. 1, the processor 120 is shown and described as calculating the target location, but when implemented, the radar device 110 performs an operation of calculating the target location, and the processor 120 may only perform control operations for the radar device 110. Additionally, the target detection device 100 may be mounted on a vehicle and operate as an autonomous driving or danger detection device.

Meanwhile, in describing FIG. 1 , the target detection device 100 is described as detecting one target, but the target detection device 100 can determine the positions of a plurality of targets in the above-described process. In addition, when implementing, it is also possible to predict the distance after proactively performing preprocessing on the radar signal.

FIG. 2 is a diagram showing a specific configuration of the processor of FIG. 1.

Referring to FIG. 2 , the processor 120 may include a signal processing unit 121, a symbol generating unit 123, and a distance calculating unit 125. Hereinafter, the description will be made assuming that the radar device in FIG. 1 is a biological FMCW radar.

The signal processing unit 121 may receive a received signal (or reflected signal) obtained from the radar device 110.

And the signal processing unit 121 may separate the breathing signal and the heart rate signal from the received signal. For example, the signal processing unit 121 may separate the breathing signal and the heart rate signal using a respiration and heart rate filter including a low-pass filter (LPF) and a high-pass filter (HPF). Additionally, the signal processing unit 121 may perform preprocessing operations of a general radar device.

And the signal processing unit 121 may separate the received signal into a plurality of chirp signals. Such chirp signal separation may be performed by the symbol generation unit 123, which will be described later.

The symbol generator 123 generates an expanded received signal using the filtered received signal. Specifically, the symbol generator 123 may separate the received signal into a plurality of chirp signals and perform expansion on each of the separated chirp signals. For example, the symbol generator 123 may expand a chirp signal by pasting one or more symbols included in the chirp signal to the rear end of the chirp signal.

When the chirp signal is expanded, the symbol generator 123 may generate an expanded received signal through calculations between symbols corresponding to the same position in the expanded chirp signal. This type of operation may be a multiplication operation, but various operation methods may be used, such as reflecting weights, rather than simple multiplication. The specific operation of the symbol generator 123 will be described with reference to FIG. 5.

The distance calculation unit 125 generates distance information using the extended received signal. Specifically, a peak may be calculated by performing a one-dimensional FFT (Fast Fourier Transform) on the extended received signal, and the distance between the target and the radar device 110 may be estimated using the calculated peak.

FIG. 3 is a diagram illustrating an example of a radar signal transmitted and a reflected signal received by a biological radar according to an embodiment of the present disclosure.

Referring to FIG. 3, the radar device 110 may generate and output a radar signal 210 having a constant period. This radar signal 210 can be defined as follows:

Here, s(t) is the radar signal 210, ω _s is the initial frequency, and μ is the rate of change of the instantaneous frequency of the chirp symbol. And, ω _BW is the bandwidth of the radar signal, and T _SYM is the signal period of the radar symbol. Here, μ is It can be.

In this way, a signal within a certain period is referred to as a chirp signal, and the radar device can combine the chirp signal into a chirp signal unit (or a preset period) and transmit it.

In this case, the distance (dm(t)) between the biological radar and the target may be d _0,m + X _m (t). Here, x _m (t) is the time-varying displacement due to the movement of the target, and d _0,m is the nominal distance of the M target with the corresponding time-varying displacement. This time-varying displacement can be expressed as Equation 2 below.

Here, x _m (t) is the time-varying displacement, x _m,h (t) is the amplitude a _m,h , and the signal of the mth target can be expressed as a sinusoid with angular frequency ω _m,h. am.

The reflected signal 220 received by the radar signal may include harmonics caused by non-linear phase modulation and movement.

A method of estimating the distance to the target using the reflection signal 220 will be described below with reference to FIG. 3.

Figure 4 is a diagram for explaining a Doppler estimation method according to an embodiment of the present disclosure.

Referring to FIG. 4, one chirp signal 401 includes a plurality of symbols. When receiving a received signal 401 having such a plurality of symbols, FFT 402 is performed on the received signal to detect peaks 403, and the distance to the target can be calculated using the interval between detected peaks. there is.

Meanwhile, if the number of symbols included in one chirp signal is small, the detected peak may not be constant. If the peak is not constant, inaccuracy may occur in the distance calculation.

In this regard, in the present disclosure, the received reflected signal (or received signal) is expanded using an extrapolation method, and the peak is detected using the expanded reflected signal. These operations will be described below with reference to FIG. 5 .

Figure 5 is a diagram for explaining an extrapolation method according to an embodiment of the present disclosure.

Referring to FIG. 5, one chirp signal will first be described. One chirp signal contains multiple symbols. At this time, the symbol 501 of one or more cycles in the chirp signal can be pasted to the rear end of the corresponding chirp signal. For example, two meaningful symbols (for example, the area with the smallest or largest phase value) in the chirp signal are detected, and a plurality of symbols between the symbols are pasted at the rear of the chirp signal to create the chirp signal. Signals can be expanded. This symbol search can be performed on one of a plurality of chirp signals, and the determined symbol interval can be equally applied to other chirp signals. Additionally, during implementation, symbol detection may not be performed, and a preset number of symbols starting from the last symbol may be pasted to the rear of the chirp signal.

In this way, when each of the plurality of chirp signals is expanded, the corresponding symbols between the plurality of chirp signals are multiplied to generate an expanded received signal. As an example, referring to FIG. 5, the first symbol of the first chirp signal at the first symbol position is , and the first symbol of the second chirp signal corresponding to the first symbol is If , the value of the first symbol of the extended received signal is This can be. As another example, referring to FIG. 5, the second symbol of the first chirp signal at the second symbol position , and the second symbol of the second chirp signal corresponding to the second symbol is If , the value of the second symbol of the extended received signal is It can be.

Meanwhile, in the illustrated example, only two chirp signals are used, but in implementation, three or more chirp signals may be used. In addition, in the present disclosure, an operation using the product between symbols is used, but in implementation, various mathematical operation methods other than the product operation can be applied. For example, various calculation methods can be used, such as additionally multiplying the product of two symbols by a weight, multiplying each symbol by a weight, and adding the two values multiplied by the weights. In addition, not only one calculation method but also a combination of multiple calculation methods may be applied.

In this way, since each of the plurality of symbols in the extended received signal has a product value between the chirp signals, the variation of the value in the extended received signal becomes larger than that of each chirp signal, making peak detection easier in the step described later. .

Figure 6 is a flowchart explaining a method for determining a target position according to an embodiment of the present disclosure.

Referring to FIG. 6, the radar signal output from the radar receives a signal reflected from the target (S610). Here, the radar signal may be a signal transmitted by a biological FMCW radar.

Then, a plurality of chirp signals included in the received reception signal are separated, and an extended reception signal is generated using the plurality of chirp signals (S620). Specifically, for each chirp signal composed of multiple symbols, the chirp signal is expanded by pasting a certain section of symbols to the rear end of the chirp signal, and the expansion is performed by performing an operation between the corresponding symbols for each of the expanded plurality of chirp signals. A received signal can be generated.

Then, distance information between the target and the radar is generated using the expanded received signal (S630). Specifically, the distance to the target can be calculated by performing FFT (fast Fourier transform) on the extended received signal.

Therefore, the target location determination method according to this embodiment estimates the distance by expanding the received signal using an extrapolation method, so that the resolution of Doppler estimation can be increased even when the observation time is short. In addition, the chirp signal is expanded and extrapolation is performed using the product between symbols within each chirp signal, so it can be performed even on hardware with low resources. The target positioning method as shown in FIG. 6 can be executed on a target positioning device having the configuration of FIG. 1, and can also be executed on a target positioning device having another configuration.

In addition, the target position determination method as described above can be implemented as a program including an executable algorithm that can be executed on a computer, and the above-described program is stored and provided in a non-transitory computer readable medium. It can be.

A non-transitory readable medium refers to a medium that stores data semi-permanently and can be read by a device, rather than a medium that stores data for a short period of time, such as registers, caches, and memories. Specifically, programs for performing the various methods described above include magnetic media, CD (Compact Disk), DVD (Digital Video Disk), hard disk, Blu-ray disk, USB, memory card, ROM (Read Only Memory), etc. It may be stored and provided in a non-transitory readable medium.

In addition, although the preferred embodiments of the present disclosure have been shown and described above, the present disclosure is not limited to the specific embodiments described above, and the technical field to which the disclosure pertains without departing from the gist of the present disclosure as claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be understood individually from the technical ideas or perspectives of the present disclosure.

100: target positioning device 110: radar device
120: processor

Claims (8)

In the target positioning device,
A radar device that emits a radar signal and receives a signal reflected from the target; and
Separate a plurality of chirp signals included in the received reception signal, generate an extended reception signal using the plurality of chirp signals, and use the extended reception signal to obtain distance information between the target and the radar. Includes a processor that generates,
The processor,
For each chirp signal composed of a plurality of symbols, each chirp signal is expanded by pasting one or more cycles of symbols to the rear end of the chirp signal, and the expansion is performed by performing an operation between the corresponding symbols for each of the expanded plurality of chirp signals. generates a received signal,
A target positioning device wherein the operation between the symbols is a multiplication operation. delete delete According to paragraph 1,
The radar device is,
Target positioning device, a biometric FMCW radar. In the target location determination method,
Receiving a signal in which the radar signal output from the radar is reflected to the target;
separating a plurality of chirp signals included in the received reception signal and generating an extended reception signal using the plurality of chirp signals; and
Comprising: generating distance information between the target and the radar using the extended received signal,
The step of generating the extended received signal is,
For each chirp signal composed of a plurality of symbols, each chirp signal is expanded by pasting one or more cycles of symbols to the rear end of the chirp signal, and the expansion is performed by performing an operation between the corresponding symbols for each of the expanded plurality of chirp signals. Including generating a received signal,
A method for determining target position, wherein the operation between the symbols is a multiplication operation. delete delete In the computer-readable recording medium including a program for executing a target position determination method,
The target position determination method is,
Receiving a signal in which the radar signal output from the radar is reflected to the target;
separating a plurality of chirp signals included in the received reception signal and generating an extended reception signal using the plurality of chirp signals; and
Comprising: generating distance information between the target and the radar using the extended received signal,
The step of generating the extended received signal is,
For each chirp signal composed of a plurality of symbols, each chirp signal is expanded by pasting one or more cycles of symbols to the rear end of the chirp signal, and the expansion is performed by performing an operation between the corresponding symbols for each of the expanded plurality of chirp signals. Including generating a received signal,
A computer-readable recording medium, wherein the operation between the symbols is a multiplication operation.

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