KR101851079B1 - A moving target detection apparatus and method using the fmcw radar - Google Patents

Abstract

Disclosed are a moving target detection apparatus and method using an FMCW radar. The moving target detection method comprises the steps of: extracting two received radar signals having a specific time interval among received radar signals received through reflection of transmitted radar signals, continuously transmitted via an antenna, on a target; calculating power spectrum density (PSD) indicating whether or not a phase change between the extracted two received radar signals occurs; and determining whether or not the target moves based on the calculated PSD, wherein the transmitted radar signals and the received radar signals can have a chirp shape of which frequency linearly changes according to time. The present invention uses the phase change when the transmitted radar signals with the chirp shape are reflected and received, thereby being capable of determining whether the target moves or not.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a moving target detection apparatus and method using an FMCW radar,

The present invention relates to an apparatus and method for detecting a moving target using an FMCW radar, and more particularly, to an apparatus and method for detecting a moving target by using a phase change when a continuously transmitted transmitted radar signal is reflected by a target and received And methods.

An algorithm for obtaining information on a moving target using radar technology is generally a Fast Fourier Transform (FFT) of radar signals of each concavity type, and the result is subjected to fast Fourier transform A 2D fast Fourier transform method is used to extract information about the target. Thus, the distance value and velocity value for the moving target can be obtained by using the radar technique using the 2D fast Fourier transform method.

In this case, if 60 radix signals of the concordance type are computed as 512 points for the first FFT and 64 points for the second FFT, the computation amount (60 * 512 point FFT computation amount) + (256 [ Use] * 64 point FFT calculation amount).

Therefore, an algorithm including such a complex calculation amount must use a hardware system capable of processing a large number of operations quickly.

However, if a target surveillance radar or a target surveillance radar is needed, the 2D fast Fourier transform algorithm consumes too much computation amount.

Accordingly, the present invention proposes a new algorithm that can determine the presence or absence of a moving target by using a phase change when a continuously transmitted transmitted radar signal is reflected and received by a target.

The present invention relates to an apparatus and method for detecting a moving target using an FMCW radar, and more particularly, to an apparatus and method for detecting a moving target by using a phase change when a continuously transmitted transmitted radar signal is reflected by a target and received And methods.

A moving target detection method according to an embodiment of the present invention includes a step of extracting two receiving radar signals having a specific time interval among received radar signals reflected from a target by a transmission radar signal continuously transmitted through an antenna ; Calculating a power spectral density (PSD) indicating whether the phase difference between the two received radar signals is changed; And determining whether the target is moved based on the calculated power spectral density, wherein the transmitting radar signal and the receiving radar signal may have a chirp shape in which the frequency varies linearly with time .

Wherein the step of calculating the power spectral density comprises: generating each beat signal using the extracted two received radar signals; Determining ADC (Analog Digital Converter) data for each bit signal by sampling each of the generated bit signals using a specific sampling frequency; And performing frequency conversion on the ADC data for each of the determined bit signals to calculate a power spectral density indicating whether the phase difference between the two received radar signals is changed.

The step of calculating the power spectral density may use the I / Q phase information of the ADC data for each bit signal subjected to the frequency conversion.

Further comprising the step of outputting the position of the moving target when it is determined that the target is moving, wherein the step of outputting the position of the moving target comprises the steps of: The frequency of the bit signal can be used.

A moving target detection apparatus according to an embodiment of the present invention includes an extraction unit that extracts two received radar signals having a specific time interval among received radar signals reflected from a target by a transmission radar signal continuously transmitted through an antenna, part; A calculation unit for calculating a power spectral density (PSD) indicating whether the phase difference between the two received radar signals is changed; And a determination unit determining whether the target is moved based on the calculated power spectral density, and the transmission radar signal and the reception radar signal may have a chirp shape in which the frequency varies linearly with time .

The calculation unit generates each beat signal using the extracted two received radar signals and samples each of the generated bit signals using a specific sampling frequency to obtain an ADC Digital converter) data, and performs frequency conversion on the ADC data of each of the determined bit signals to calculate a power spectral density indicating whether the phase difference between the two received radar signals is changed.

The calculator may use the I / Q phase information of the ADC data for each bit signal subjected to the frequency conversion.

And an output unit outputting the position of the moving target when it is determined that the target is moving, and the output unit may use the frequency of each bit signal generated using the extracted two receiving radar signals .

According to the embodiment of the present invention, it is possible to judge whether or not the target is moved by using the phase change when the concatenated transmission radar signal transmitted continuously is reflected and received by the target.

1 is a view illustrating a moving target detection apparatus according to an embodiment of the present invention.
2 is a diagram illustrating a background of an algorithm for a moving target detection apparatus to detect a moving target according to an embodiment of the present invention.
3 is a diagram illustrating an example of a radar signal used by a moving target detection apparatus according to an embodiment of the present invention.
4 is a diagram illustrating a moving target detection method performed by the moving target detection apparatus according to an embodiment of the present invention.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, for example, "between" and "immediately" or "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", and the like, are used to specify one or more of the features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

1 is a view illustrating a moving target detection apparatus according to an embodiment of the present invention.

The moving target detection apparatus 100 of the present invention provides a method of determining whether or not a target is moved using an FMCW radar. At this time, the radar signal transmitted / received through the antenna of the moving target detection apparatus 100 may have a chirp shape in which the frequency varies linearly with time.

Specifically, the moving target detection apparatus 100 can continuously transmit the concave transmission radar signals with a constant period as shown in FIG. Then, the continuously transmitted transmission radar signal can be reflected by the target and received through the moving target detection apparatus 100.

In the moving target detection method using the conventional FMCW radar, as shown in FIG. 3, a continuously transmitted transmission radar signal is reflected by the target and all received radar signals are used. Therefore, the computation to be processed is complicated and a lot of resources are required.

In contrast, the moving target detection apparatus 100 of the present invention uses only two received radar signals having a specific time interval among the received radar signals reflected from the target by continuously transmitting transmitted radar signals, A new algorithm is provided to judge whether or not there is a problem. At this time, this new algorithm can be made in the background of the following two conditions.

(1) If the target is stationary, the continuously transmitted transmitted radar signals are reflected by the target, and the received radar signals have a constant value without change in phase.

For example, assume that the mobile target detection apparatus 100 has transmitted L transmitted radar signals continuously toward a stationary target. The mobile target detection apparatus 100 may then receive L received radar signals whose L transmitted radar signals are reflected by the target. At this time, the receiving radar signal received by the moving target detecting apparatus 100 has a constant value without changing the phase because the target is stopped.

Therefore, in this case, all of the bit signals from the first beat signal, in which the first transmission radar signal and the first reception radar signal are mixed, to the L th bit signal where the L th transmission radar signal and the L reception radar signal are mixed, And can have the same phase.

2 (a) shows a graph in which the first bit signal and the L-bit signal of the plurality of bit signals are selected and overlapped when the target is stopped. Since the target is stationary and all bit signals have the same phase, the first bit signal and the L bit signal can be combined into one as shown in FIG. 2A.

FIG. 2 (b) is a graph showing a phase change with respect to a specific index part of the first bit signal to the L-bit signal when the target is stopped. Since the target is stationary and all bit signals have the same phase, it can be seen that there is no phase change of the stationary target.

(2) Otherwise, if the target is in a moving state, the received radar signals reflected from the target by the continuously transmitted transmission radar signals are received at different times, and a phase change occurs.

Therefore, in this case, a first beat signal in which the first transmission radar signal and the first reception radar signal are mixed, and a L th bit signal in which the L th transmission radar signal and the L th reception radar signal are mixed, The phase can be changed.

2C shows a graph in which the first bit signal and the L bit signal of the plurality of bit signals are selected and overlapped when the target moves. Since the phases of all the bit signals are different due to the movement of the target, the first bit signal and the L th bit signal may not overlap with each other as shown in (c) of FIG.

FIG. 2 (d) shows a graph of the phase change with respect to a specific index part of the first bit signal to the L-bit signal when the target moves. Since the phase of all the bit signals is changed due to the movement of the target, it can be confirmed that the phase change of the moving target occurs.

In this way, the moving target detection apparatus 100 of the present invention can determine whether or not the target is moved by using the phase change of the received radar signals. At this time, the moving target detection apparatus 100 can reduce the required memory space and calculation amount by determining whether or not the target is moved by using two receiving radar signals having a specific time interval among the receiving radar signals, unlike the existing method .

More specifically, referring to FIG. 1, the moving target detection apparatus 100 may include an extraction unit 110, a calculation unit 120, a determination unit 130, and an output unit 140. The extracting unit 110 may extract two receiving radar signals having a specific time interval among the receiving radar signals reflected from the target by the transmission radar signal continuously transmitted through the antenna. For example, the extracting unit 110 may select and extract the first transmission radar signal among the plurality of reception radar signals and the reception radar signals corresponding to the Nth transmission radar signal transmitted after the user-defined delay time have.

The calculation unit 120 may calculate a power spectral density (PSD) indicating whether the phase difference between the two received radar signals is changed. More specifically, the calculated power spectral density may have a larger value when moving, than when the target is stationary.

Specifically, the calculation unit 120 may include a configuration of the generation unit 121, the determination unit 122, the conversion unit 123, and the processing unit 124. [ The generating unit 121 may generate each beat signal using the two received radar signals. For example, if it is assumed that the first transmission radar signal among the plurality of reception radar signals and the reception radar signals corresponding to the Nth transmission radar signal transmitted after the predetermined delay time are extracted through the extraction unit 110 . The generator 121 multiplies each first transmission radar signal by the first reception radar signal to generate a first bit signal, multiplies the Nth transmission radar signal by the Nth reception radar signal to generate an Nth bit signal . At this time, the generated bit signal includes the distance information of the target.

The determination unit 122 may determine ADC (Analog Digital Converter) data for each bit signal by sampling each bit signal generated through the generation unit 121 using a specific sampling frequency.

The conversion unit 123 may perform frequency conversion on the ADC data for each determined bit signal. Specifically, the conversion unit 123 may perform fast Fourier transform on the ADC data for each bit signal. At this time, the ADC data for each bit signal subjected to the fast Fourier transform may include phase information of the I channel and the Q channel.

The processing unit 124 obtains the difference between the I-channel phase information and the Q-channel phase information obtained through the transform unit 123, and then applies a root square to obtain a power spectrum indicating the phase change between the two received radar signals. The density can be calculated.

The determination unit 130 may determine whether the target is moved based on the calculated power spectral density. More specifically, the determination unit 130 may determine that the target is moving if the calculated power spectral density is greater than a threshold value specified by the user, and may determine that the target is stationary if the calculated power spectral density is less than the threshold value.

The output unit 140 may output the position of the moving target when it is determined that the target is moving. Specifically, the output unit 140 can output the position of the moving target by using the frequency of each bit signal generated using the two received radar signals.

As described above, the moving target detection apparatus 100 of the present invention is advantageous in that a required memory space and a computation amount can be reduced by determining whether a target is moved using only two received radar signals having a specific time interval among received radar signals .

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

100: Moving target detection device
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120:
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Claims (8)

A transmission radar signal continuously transmitted through the antenna is reflected by the target, and a first reception radar signal corresponding to a first transmission radar signal of the received reception radar signals and a second reception radar signal corresponding to a predefined delay Extracting a second received radar signal corresponding to a second transmitted radar signal transmitted after the second received radar signal;
Mixing the first transmission radar signal and the first reception radar signal to generate a first bit signal and mixing the second transmission radar signal and the second reception radar signal to generate a second bit signal;
Sampling the first bit signal and the second bit signal using a specific sampling frequency to determine ADC (Analog Digital Converter) data for the first bit signal and the second bit signal;
Identifying an I-channel phase and a Q-channel phase for the first bit signal and the second bit signal, respectively, by frequency-converting the determined ADC data;
And a difference between I channel phase differences for the identified first bit signal and the second bit signal and Q channel phase for the identified first bit signal and the second bit signal, Calculating a phase change between two received radar signals; And
Determining that the target is in motion if the calculated phase difference between the first received radar signal and the second received radar signal is greater than a preset threshold value and determining that the target is in motion if it is smaller
Lt; / RTI >
The transmission radar signal and the reception radar signal are transmitted,
A moving target detection method having a chirp type in which the frequency varies linearly with time delete delete The method according to claim 1,
If it is determined that the target is moving, outputting the position of the moving target
Further comprising:
Wherein the step of outputting the position of the moving target comprises:
Wherein the frequency of each bit signal generated using the extracted two received radar signals is used. A transmission radar signal continuously transmitted through the antenna is reflected by the target, and a first reception radar signal corresponding to a first transmission radar signal of the received reception radar signals and a second reception radar signal corresponding to a predefined delay An extracting unit for extracting a second received radar signal corresponding to a second transmitted radar signal transmitted after a predetermined time;
Mixes the first transmission radar signal and the first reception radar signal to generate a first bit signal, mixes the second transmission radar signal and the second reception radar signal to generate a second bit signal, Signal and a second bit signal using a specific sampling frequency to determine ADC (Analog Digital Converter) data for the first bit signal and the second bit signal, and frequency-converts the determined ADC data, Channel phase and a Q-channel phase for the first bit signal and the second bit signal, respectively, and for identifying the difference between the I-channel phase for the identified first bit signal and the identified first bit signal, A calculation unit for calculating a phase change between the first reception radar signal and the second reception radar signal by using a difference of a Q channel phase with respect to a 2-bit signal; And
Determining that the target is moving if the phase change between the calculated first received radar signal and the second received radar signal is greater than a preset threshold value,
Lt; / RTI >
The transmission radar signal and the reception radar signal are transmitted,
A mobile target detection device having a chirp shape in which the frequency varies linearly with time. delete delete 6. The method of claim 5,
When it is determined that the target is moving,
Further comprising:
The output unit includes:
And the frequency of each bit signal generated using the extracted two received radar signals is used.

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