KR20190081257A - Radar apparatus and method for detecting High Resolution Doppler using the same - Google Patents

Abstract

The present invention relates to a radar apparatus and a high-resolution doppler extraction method using the same. According to the present invention, the high-resolution doppler extraction method using the radar apparatus includes: a step of transmitting M radar signals, and receiving M signals reflected through a plurality of reception antennas; a step of executing range-FFT with an ADC in regard to the M received signals and storing a processing result in M memories; a step of generating a low-resolution range-speed two-dimensional map; a step of selecting a range-speed signal value higher than a first threshold value; and a step of determining whether a new interest target enters a detection area. According to the present invention, since a high-resolution range-speed doppler spectrum component is selected and extracted, computation can be considerably reduced.

Description

The present invention relates to a radar apparatus and a high resolution Doppler extracting method using the same,

The present invention relates to a radar apparatus and a high-resolution Doppler extracting method using the same, and more particularly, to a high-resolution Doppler extracting method using a radar apparatus capable of greatly reducing a calculation amount and rapidly detecting a target.

Radar is a device that can find out information such as distance, speed, and angle of target. That is, the radar emits an electromagnetic wave signal through the transmission antenna, receives a signal reflected from the target and returns from the reception antenna, and can use the received signal to find the distance and velocity information of the target.

According to the target detection method using the existing radar, the distance, speed and angle of the target are extracted, and all the targets are extracted as one point. However, in order to recognize the target type, motion, etc. based on the radar, high-resolution Doppler spectrum for each moving target should be extracted.

FIG. 1 is a view for explaining a distance-velocity extraction method of a general FMCW radar, and FIG. 2 is a diagram illustrating a distance-velocity-angle extraction method of the FMCW radar according to FIG.

According to the general FMCW radar distance-velocity extraction method according to FIG. 1, first, the FMCW radar sensor transmits M sawtooth-shaped frequency modulated signals at periodic intervals of T. FIG. Where the Doppler resolution is proportional to the number of M's.

For each lamp cycle, the received signal is stored in memory via an ADC (Analog Digital Converter) and a distance-FFT. Once the radar signals received for each ramp cycle are stored in the memory, the Doppler spectrum is extracted via Doppler-FFT for signals of the same distance spanning M lamps. Then, the 2D map corresponding to the distance is extracted and the distance is taken as the distance.

Next, the thresholding module scans both the distance-velocity 2D map and recognizes the corresponding cell as a target when the magnitude of the signal stored in each cell is higher than a specific criterion. Therefore, target information (distance and speed) corresponding to the finally corresponding cell is extracted.

In order to extract the high-resolution Doppler, the number of lamps M must be large, but the distance-velocity 2D map also has to be large. As a result, more cells need to be scanned in the Thresholding module. This lowers the overall signal processing speed and makes real-time processing difficult.

On the other hand, as shown in FIG. 2, when the number of receiving antennas is plural (K), the distance-velocity-angle of the target can be extracted. 1, except that a digital beamforming algorithm is inserted before the Doppler FFT and the FFT is performed once more in the direction of the receive channel. That is, the Thresholding module scans the 3D map.

Therefore, as the number of pulses M increases, the number of cells to be scanned for thresholding increases and the total amount of calculation increases accordingly.

That is, both FMCW radar or Pulse-Doppler radar in the form of a general sawtooth modulation must increase the number of ramps or pulses to extract a high-resolution Doppler spectrum. However, this increases the calculation amount of the Doppler FFT and increases the total signal processing time because the number of cells to be scanned by the thresholding module increases.

The technology of the background of the present invention is disclosed in Korean Patent Laid-Open Publication No. 2017-0133804 (published on December 12, 2017).

An object of the present invention is to provide a radar device capable of greatly reducing the amount of calculation and detecting a target quickly, and a high-resolution Doppler extracting method using the same.

According to the present invention, there is provided a high-resolution Doppler extracting method using a radar device, comprising the steps of: transmitting M radar signals at regular intervals through a transmitting antenna and receiving M signals reflected through a plurality of receiving antennas; Performing FFT (Range-FFT) conversion on an ADC with respect to a received signal and storing the result of the processing in M memories, processing the distance of N received signals corresponding to a part of the M received signals, Comparing the signal value of the distance-velocity stored in the low resolution distance-velocity 2D map with the first threshold value by performing Doppler-FFT (Doppler-FFT) Selecting a signal value of a distance-velocity higher than the first threshold value, comparing the signal value of the selected distance-velocity with a previously stored 2D map database, Speed 2D map by performing Doppler-FFT transform on the result of processing the distance-FFT of M received signals corresponding to the distance-velocity of the target of interest, And comparing the signal value of the distance-velocity of the target of interest stored in the high resolution distance-velocity 2D map with a second threshold to determine whether the target of interest is an actual target or clutter do.

Performs Doppler-FFT (Doppler-FFT) conversion on the angle-component values of the target by performing digital beamforming on the received signals corresponding to the plurality of reception-channels subjected to the distance-FFT transformation, And generating a 3D map.

The first threshold value may have a value lower than the second threshold value.

The 2D map database may store the distance-speed signal values of the targets fixed in the detection area.

The step of determining whether or not the new interest target has entered has been performed by determining that a new interest target has entered the detection area when the cell corresponding to the selected distance-speed signal value is not stored in the previously stored 2D map database can do.

According to another aspect of the present invention, there is provided a radar apparatus including a radar transmitter for transmitting M radar signals at regular intervals through a transmission antenna, a radar receiver for receiving M signals reflected through a plurality of reception antennas, A distance-FFT conversion unit for performing ADC-to-FFT (Range-FFT) conversion on the received signal and storing the processed result in M memories, A first Doppler-FFT transformer for performing a Doppler-FFT (FFT) transformation on the result of the FFT processing to generate a low resolution distance-velocity 2D map, a first Doppler- Comparing the signal value with a first threshold value, selecting a signal value of a distance-velocity higher than the first threshold value, comparing the signal value of the selected distance-velocity with a previously stored 2D map database A map comparing unit for determining whether a new target of interest has entered the detection area, a DFT-FFT transforming unit for performing Doppler-FFT processing on the distance-FFT processing result of M received signals corresponding to the distance- A second Doppler-FFT transformer for generating a velocity 2D map, and comparing the distance-velocity signal value of the target of interest stored in the high resolution distance-velocity 2D map to a second threshold value, And determines whether the target is a target or a clutter.

According to the present invention, when a target enters a radar detection area or a target moves, a target of interest is preferentially detected using a part of received signals, and a Doppler spectrum component of a high resolution distance-velocity is selected only for the detected target of interest The amount of calculation can be greatly reduced.

Also, according to the present invention, it is possible to quickly detect a target by reducing the amount of calculation required for extracting the Doppler spectrum.

1 is a view for explaining a distance-velocity extraction method of a general FMCW radar.
FIG. 2 is a view showing a distance-velocity-angle extraction method of the FMCW radar according to FIG.
3 is a configuration diagram of a radar apparatus according to an embodiment of the present invention.
4 is a view for explaining a process of monitoring a detection area by the radar device according to FIG.
5 is a flowchart of a high-resolution Doppler extracting method according to an embodiment of the present invention.
6 is an overall block diagram of a high-resolution Doppler extracting method according to an embodiment of the present invention.
7 is a diagram for explaining a first step of a high-resolution Doppler extracting method according to an embodiment of the present invention.
8 is a diagram for explaining a second step of the high-resolution Doppler extracting method according to the embodiment of the present invention.
9 is a diagram for explaining a third step of the high-resolution Doppler extracting method according to the embodiment of the present invention.
FIG. 10 is a diagram for explaining a process of a cell corresponding to each step of the high-resolution Doppler extracting method according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

FIG. 3 is a block diagram of a radar device according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating a process of monitoring a detection area by the radar device according to FIG.

3, the radar apparatus 300 according to the embodiment of the present invention includes a radar transmitter 310, a radar receiver 320, a distance-FFT converter 330, a first Doppler-FFT unit 340 A map comparing unit 350, a second Doppler-FFT unit 360, and a target determining unit 370, and may further include a digital beamforming unit 380.

First, the radar transmitter 310 transmits M radar signals at predetermined intervals to the detection area using one transmission antenna.

Here, the radar signal is an FMCW signal of a sawtooth modulation method, and may be a pulse Doppler signal of a rectangular wave form.

The radar receiver 320 receives M signals reflected from the object through a plurality of reception antennas.

The distance-to-FFT converter 330 performs an analog-to-digital converter (ADC) and a distance-to-FFT (FFT) conversion on M received signals and stores the processed results in M memories.

The first Doppler-FFT conversion unit 340 performs Doppler-FFT (Doppler-FFT) conversion on the result of processing the distance-FFT of N received signals corresponding to a part of the M received signals, Create a 2D map.

The map comparing unit 350 compares the signal value of the distance-velocity stored in the low resolution distance-velocity 2D map with the first threshold value, and selects the signal value of the distance-velocity higher than the first threshold value.

Then, the map comparing unit 350 compares the signal value of the selected distance-speed with the pre-stored 2D map database to determine whether a new interest target has entered the detection area.

The second Doppler-FFT transform unit 360 performs Doppler-FFT transform on the processing result of the distance-FFT of M received signals corresponding to the distance-velocity of the target of interest to generate a high resolution distance-velocity 2D map.

Meanwhile, the second Doppler-FFT conversion unit 360 is separated from the first Doppler-FFT conversion unit 340 for the sake of convenience of description, and can operate substantially as a single component.

The target determination unit 370 compares the distance-velocity signal value of the target of interest stored in the high-resolution distance-velocity 2D map with a second threshold value to determine whether the target of interest is an actual target or clutter.

The digital beamforming unit 380 performs digital beamforming on the received signals corresponding to the plurality of receive-channels subjected to the distance-FFT transform, detects the angle component value of the target, Thereby generating an angular 3D map.

As described above, the radar device 300 according to the embodiment of the present invention is a sensor device that extracts target information based on a reflected signal by transmitting a radio wave signal. A target is detected in a radar detection area When the target enters or moves, the distance-angle of the target is detected first, and only the Doppler spectrum component of the detected distance-angle is selected and extracted, thereby reducing the amount of calculation.

Hereinafter, a high-resolution Doppler extracting method according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a flowchart illustrating a method of extracting a high-resolution Doppler according to an embodiment of the present invention, and FIG. 6 is a block diagram of an overall method of extracting a high-resolution Doppler according to an exemplary embodiment of the present invention.

The high-resolution Doppler extracting method according to the embodiment of the present invention is largely composed of three steps. The first step is to store the data in the memory after the ADC and distance-FFT processing. The second step is to extract the distance-angle to the ROI, Is a step of extracting a high-resolution Doppler.

7 is a view for explaining a first step of a high-resolution Doppler extracting method according to an embodiment of the present invention, FIG. 8 is a view for explaining a second step of a high-resolution Doppler extracting method according to an embodiment of the present invention, 9 is a diagram for explaining a third step of the high-resolution Doppler extracting method according to the embodiment of the present invention.

10 is a diagram for explaining a process of a cell corresponding to each step of the high-resolution Doppler extracting method according to the embodiment of the present invention.

For convenience of description, the FMCW radar apparatus will be described as an example of the present invention, and the pulse-Doppler radar apparatus can detect the Doppler spectrum in the same manner.

First, the process of storing data in the memory after the ADC and the distance-FFT process of the first step of the present invention will be described with reference to FIGS. 5, 6, 7 and 10. FIG.

First, the radar transmitter 310 transmits M frequency-modulated signals every interval T (S510).

That is, one transmitting antenna emits M radar signals at intervals of T intervals.

Here, if the radar apparatus is an FMCW radar apparatus, a sawtooth-shaped frequency modulated signal is transmitted, and if the radar apparatus is a pulse-Doppler radar apparatus, a spherical-wave shaped frequency modulated signal is transmitted.

Then, a plurality of (K) receiving antennas included in the radar receiving unit 320 receive a sawtooth signal reflected from the target as shown in FIG. 7 (S520).

The distance-to-FFT conversion unit 330 performs distance-to-FFT (FFT) conversion on the M signals received for each of the lamp periods with an ADC (Analog Digital Converter), and the processing results are stored in M memories S530).

Here, the signals are stored in the memory in the order in which the signals are received. Since the time difference of the received signals corresponds to the range of the target, the distance to the target can be mapped in the order stored in the memory.

As shown in FIG. 10, the received signal is converted into a range-bin format through the distance-FFT process, and is stored in the memory for each of the reception channels corresponding to the number of reception antennas.

When a digital beam forming (DBF) process is performed, a plurality of reception channels are converted into an angle-bin format and stored. Therefore, the digital beamforming (DBF) is performed only when an angle component to the target is required. Since the plurality of reception antennas are spaced apart from each other and the angles to the target are different from each other, The angular component can be detected.

Next, a description will be given of a process of extracting the distance-angle with respect to the target of interest (ROI), which is the second step of the present invention, with reference to FIGS. 5, 6, 8 and 10. FIG.

8, the first Doppler-FFT conversion unit 340 converts the radar signals received into the N lamps, which are part of the M lamps, And performs Doppler-FFT transform on the corresponding distance-FFT processing result to generate a distance-velocity 2D map (S540). At this time, the distance-velocity 2D map represents a velocity in a horizontal direction and a range in a vertical direction, and has a low-resolution Doppler component.

That is, since the 2D map is generated through the Doppler-FFT transform only for N lamp signals which are a part of the M ramp signals, the 2D map has lower resolution than the case where Doppler-FFT transform is performed using all the M lamp signals.

On the other hand, when a digital beamforming (DBF) process is performed by the digital beamforming unit 380, a 3D map of the distance-velocity-angle is generated.

Next, the map comparator 350 compares the distance-velocity signal value stored in the distance-velocity 2D map with a first threshold value and calculates a distance-velocity corresponding to the distance-velocity having a signal value higher than the first threshold value Cells are selected (S550).

That is, since the distance-velocity value stored in the distance-velocity 2D map may include clutter or noise, the map comparing unit 350 may calculate a distance-velocity value having a signal value higher than the first threshold value, And estimates the signal as a target.

At this time, the map comparator 350 may adaptively change the first threshold value for the distance-speed according to the resolution of the distance-speed stored in the distance-speed 2D map (Adaptive Thresholding).

In particular, since the distance-velocity 2D map generated in step S550 has a low resolution, the map comparator 350 can set the first threshold value for distance and angle lower than the reference. Therefore, in some cases, non-target clutters may be selected, and multiple targets of interest (ROI) may be selected.

Next, the map comparator 350 compares the signal value of the selected distance-speed with a pre-stored 2D map database (Map 2D comparator) to determine whether or not a new ROI has entered the detection area (S560).

Since the distance-velocity components of the targets that are normally fixed in the detection area are stored in the previously stored 2D map database (DB 2D map), the target determination unit 260 determines the distance-velocity 2D map and the 2D map database DB 2D map) to determine whether a new interest target has entered the detection area.

That is, when the cell corresponding to the signal value of the selected distance-speed is not stored in the pre-stored 2D map database, the map comparator 350 determines that a new interest target has entered the detection area.

When the target of interest is detected through the second step, in step 3, a high resolution Doppler component for the target of interest is extracted using all the M lamp signals.

Hereinafter, a process of extracting a high-resolution Doppler for a target ROI according to a third embodiment of the present invention will be described with reference to FIGS. 5, 6, 9, and 10. FIG.

The second Doppler-FFT transform unit 360 performs Doppler-FFT transform on the M ramp signals corresponding to the cell corresponding to the distance-angle of the ROI selected in step S560 to obtain a high-resolution distance-velocity 2D And generates a map (S570).

At this time, the second Doppler-FFT transform unit 360 extracts the Doppler spectrum for all of the M lamps, so that a high-resolution distance-velocity 2D map is generated.

If only one ROI is selected in step S560, only one Doppler-FFT conversion may be performed.

The target determining unit 370 compares a cell corresponding to the distance-angle of the ROI with a second threshold value among the high-resolution distance-velocity 2D maps to search for a high-resolution Doppler component, It is determined whether the target is a clutter or not (S580).

That is, if the value of the Doppler spectrum (distance and angle) of the ROI is higher than the second threshold value, the target is determined as an actual target. If the value is lower than the second threshold value, the clutter is determined.

At this time, since the 2D map generated in step S570 is acquired using M ramp signals and has a high resolution, the target determining unit 370 may set the level of the second threshold to be higher than the first threshold in step S550 have.

As described above, according to the embodiment of the present invention, when the target enters the radar detection region or the target moves, the target of interest is preferentially detected using a part of the received signals, and only the high-resolution distance- By selecting and extracting Doppler spectral components, the amount of calculation can be greatly reduced.

Further, according to the embodiment of the present invention, it is possible to quickly detect the target by reducing the amount of calculation required for extracting the Doppler spectrum.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

300: Radar device 310: Radar transmitter
320: Radar reception unit 330: Distance-FFT conversion unit
340: first Doppler-FFT unit 350: map comparing unit
360: second Doppler-FFT unit 370:
380: digital beam forming section

Claims (10)

A high-resolution Doppler extracting method using a radar device,
Transmitting M radar signals at regular intervals through a transmission antenna and receiving M signals reflected through a plurality of reception antennas,
Performing a range-to-FFT (ADC-to-FFT) conversion on the M received signals and storing the processed results in M memories,
Performing Doppler-FFT (Doppler-FFT) conversion on the result of processing the distance-FFT of N received signals corresponding to a part of the M received signals to generate a low resolution distance-speed 2D map;
Comparing the signal value of distance-velocity stored in the low resolution distance-velocity 2D map with a first threshold value, selecting a signal value of distance-velocity higher than the first threshold value,
Comparing the signal value of the selected distance-speed with a pre-stored 2D map database to determine whether a new interest target has entered the detection area,
Generating a high resolution distance-velocity 2D map by performing Doppler-FFT transform on the processing result of the distance-FFT of M received signals corresponding to the distance-velocity of the target of interest; and
Comparing the signal value of the distance-velocity of the target of interest stored in the high resolution distance-velocity 2D map with a second threshold to determine whether the target of interest is an actual target or clutter, Way. The method according to claim 1,
Performs Doppler-FFT (Doppler-FFT) conversion on the angle-component values of the target by performing digital beamforming on the received signals corresponding to the plurality of reception-channels subjected to the distance-FFT transformation, And generating a 3D map. The method according to claim 1,
Wherein the first threshold value is lower than the second threshold value. The method according to claim 1,
Wherein a distance-velocity signal value of targets fixed in the detection area is previously stored in the 2D map database. The method of claim 4,
Wherein the step of determining whether the new interest target has entered comprises:
Wherein when a cell corresponding to the selected distance-velocity signal value is not a cell stored in a previously stored 2D map database, it is determined that a new interest target has entered the detection area. A radar transmitter for transmitting M radar signals at regular intervals through a transmission antenna,
A radar receiver for receiving M signals reflected through a plurality of reception antennas,
A distance-to-FFT (M-FFT) converter for performing ADC-to-FFT (Range-FFT) conversion on the M received signals,
A first Doppler-FFT (DFT-FFT) process for performing Doppler-FFT (Doppler-FFT) conversion on the distance-FFT processing result of N received signals corresponding to a part of the M received signals to generate a low- Conversion section,
Comparing the signal value of distance-velocity stored in the low resolution distance-velocity 2D map with a first threshold value, selecting a signal value of distance-velocity higher than the first threshold value, A map comparator for comparing the detected 2D map database with a previously stored 2D map database to determine whether a new interest target has entered the detection area,
A second Doppler-FFT transformer for performing a Doppler-FFT transform on the processing result of the distance-FFT of M received signals corresponding to the distance-velocity of the target of interest to generate a high-resolution distance-velocity 2D map,
And a target determining unit for determining whether the target of interest is an actual target or clutter by comparing the signal value of the distance-velocity of the target of interest stored in the high resolution distance-velocity 2D map with a second threshold value. . The method of claim 6,
Performs a digital beamforming on the received signals corresponding to the plurality of reception channels corresponding to the distance-FFT transform to detect the angle component value of the target, and generates a distance-velocity-angle 3D map through Doppler- And a digital beamforming unit. The method of claim 6,
Wherein the first threshold value has a value lower than the second threshold value. The method of claim 6,
Wherein the 2D map database stores the distance-velocity signal values of the targets fixed in the detection area. The method of claim 9,
The map comparing unit,
And determines that a new interested target has entered the detection area when the cell corresponding to the selected distance-speed signal value is not stored in the pre-stored 2D map database.

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