KR20180064127A - Method for detecting target object and apparatus thereof - Google Patents

Abstract

The present invention relates to a method for detecting a target object by a radar apparatus for a vehicle and an apparatus thereof and, more specifically, to a method for increasing the detection performance of a target object by recognizing an interference signal, received by a radar apparatus of another vehicle, and suppressing the same, and to an apparatus thereof. According to one embodiment of the present invention, the apparatus comprises: a signal transmission unit for transmitting a transmission signal for detecting a target object; a signal reception unit for receiving a reception signal including a target signal, generated by reflecting the transmission signal from the target object; a signal analysis unit for calculating frequency spectrum information of the reception signal, and extracting periodic information for confirming periodicity of the frequency spectrum information; a determination unit for determining whether an interference signal is included in the reception signal on the basis of periodicity information; and a target detection unit for extracting the target signal by suppressing the interference signal.

Description

[0001] METHOD FOR DETECTING TARGET OBJECT AND APPARATUS THEREOF [0002]

The present invention relates to a method and apparatus for detecting a target object by a radar apparatus for a vehicle, and more particularly to a method and apparatus for detecting a target object by detecting an interference signal received by a radar apparatus of another vehicle And apparatus. .

The term "vehicle radar" refers to various types of radar devices that can be mounted on a vehicle. The term "vehicle radar" refers to a device used to detect an object around a vehicle and prevent the occurrence of an accident due to poor weather conditions or carelessness of a driver.

[0003] Recently, as interest in safety and driver convenience has increased, various vehicle safety and convenience technologies using such a vehicle radar device have been developed. For example, various technologies such as a smart cruise technology, an automatic driving technology, and an automatic emergency stop technology have been developed such that a front vehicle is detected and the front vehicle detected is automatically followed and driven.

Automotive radars, which can be used extensively in these technologies, can detect nearby objects by using a signal that is reflected by the object after transmitting the signal.

However, due to the widespread use of radars for vehicles, there is a problem of interference between radar signals. In particular, when the radar signal of the interfering vehicle is transmitted with a pulse that is very short compared to the radar signal of the subject vehicle, the radar signal of the interfering vehicle is received in a highly repetitive and periodic manner within one period of the subject vehicle radar receiving signal. As a result, it is difficult to detect the target signal of the subject vehicle.

In this background, the present embodiment proposes a method and apparatus for analyzing a received signal acquired by a radar device to check whether an interference signal due to another radar signal exists.

In addition, the present embodiment intends to improve the target object detection performance by checking the type of the interference signal through analyzing the received signal and setting the target object detection parameter classified according to the type of the interference signal.

In order to solve the above-described problems, one embodiment of the present invention provides a signal receiving apparatus including: a signal transmitter for transmitting a transmission signal for detecting a target object; a signal receiver for receiving a reception signal including a target signal generated by reflecting a transmission signal on a target object; A signal analyzer for calculating frequency spectrum information of the signal and extracting periodicity information for confirming the periodicity of the frequency spectrum information, a determination unit for determining whether the interference signal is included in the received signal based on the periodicity information, And a target detector for extracting a target signal from the target object.

One embodiment includes a signal transmission step of transmitting a transmission signal for detecting a target object, a signal reception step of receiving a reception signal including a target signal generated by reflecting a transmission signal on a target object, and calculating frequency spectrum information of the reception signal A signal analysis step of extracting periodicity information for confirming the periodicity of the frequency spectrum information, a determination step of determining whether an interference signal is included in the received signal based on the periodicity information, a target step of extracting a target signal by removing the interference signal, And detecting the target object.

As described above, according to the present embodiment, there is an effect that the target object detection performance can be improved by effectively removing the interference signal by analyzing the received signal acquired by the target object detection device.

Also, according to the present embodiment, the target object detection performance can be improved even in an environment where various interference signals exist by classifying the types of the interference signals and adjusting the target detection parameters accordingly.

FIG. 1 is a diagram for explaining deterioration of detection performance of a target signal according to an interference signal.
2 is a block diagram of a target object detection apparatus according to an embodiment of the present invention.
3 is a diagram illustrating exemplary periodic information extracted through Fast Fourier Transform according to an embodiment.
4 is a diagram illustrating an example of a binary frequency spectrum according to an exemplary embodiment of the present invention.
5 is a diagram exemplarily showing periodicity information extracted using a binary frequency spectrum according to an exemplary embodiment.
6 is an exemplary diagram illustrating a binary peak frequency spectrum according to one embodiment.
FIG. 7 is a diagram illustrating exemplary periodic information extracted using a binary peak frequency spectrum according to an exemplary embodiment. Referring to FIG.
FIG. 8 is an exemplary diagram illustrating periodicity information extracted through inverse fast Fourier transform according to an embodiment.
FIG. 9 is a diagram for explaining an operation for classifying an interference signal type according to an embodiment.
10 is a diagram exemplarily showing a spectrum suppressing a peak value component in periodicity information according to an embodiment.
11 is a view for explaining a converted frequency spectrum after suppressing a peak value component according to an embodiment.
12 is a flowchart illustrating a method of detecting a target object according to an embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In describing the components of the present invention, the terms first, second, A, B, (a), (b), and the like can be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

The present invention discloses a target object detection apparatus and a target object detection method.

A variety of driver convenience functions are being developed using radar in the situation where the radar for vehicles is becoming popular. The Adaptive Cruise Control (ACC) function is one such convenience feature that automatically controls the speed or steering of the vehicle while automatically maintaining the safety distance to the target vehicle ahead.

However, the high reliability of the radar device capable of continuously detecting and tracking the vehicle ahead is very important in order for these functions to operate normally and provide convenience to the driver. The radar device is more reliable than other sensors such as a camera in a heavy rain or fog situation where the field of view is not ensured. However, in the presence of radar signals transmitted from various structures on the road or opposite vehicles, various types of interference signals Thereby deteriorating the performance of detecting a target object.

For example, the mutual interference of a frequency modulated continuous waveform (FMCW) radar appears in the form of a noise power increase resulting in the failure of target detection due to interference signals. In particular, when the interference signal of the interfering vehicle transmits a pulse that is very short compared to the radar of the vehicle, the interfering signal is received in a very repetitive and periodic manner in the time domain within one period of the vehicle radar reception signal, . Also, in a road environment with dense steel structures, the transmission signal transmitted by the vehicle can be reflected on the iron structure and received as a clutter signal, and this clutter signal also has an adverse effect on the target detection by an interference signal.

In order to solve such a problem, the present embodiment describes a target object detection apparatus and a target object detection method which can detect a target object quickly and accurately by detecting and removing an interference signal even in an environment where an interference signal is generated due to a number of factors do. In addition, in the present embodiment, a method and an apparatus for providing more accurate target object detection performance by dynamically changing parameters in a signal processing process for detecting a target object by distinguishing types of interference signals will be described.

Clutter described below refers to reflection obstacles such as echo caused by unwanted reflection waves generated from the ground, sea surface, raindrops, etc. in the radar technology. In the present specification, the clutter structure means an object causing the clutter, and the clutter signal means a signal component received by the radar by unnecessary reflected waves. The clutter signal is distinguished from the general noise signal and can be received at a stronger intensity than the target signal by the target object, thus causing a problem in the detection of the target object. In the following, the described clutter structure may refer to a structure on the roadway or on the road that generates a clutter signal when a radar signal is received.

In this specification, a radar signal due to another vehicle or a clutter signal due to a clutter structure is described as an interference signal. That is, the interference signal may be used to include a radar signal and a clutter signal, and may also mean various signals that can weaken the detection performance of a target signal.

FIG. 1 is a diagram for explaining deterioration of detection performance of a target signal according to an interference signal.

1, in a situation 100 where the vehicle 110 and the other vehicle 120 travel in opposite directions, the radar transmission signal of the vehicle 110 and the radar transmission signal of the other vehicle 120 are mutually interference Lt; / RTI > For example, the radar transmission signal of the other vehicle 120 may be received by the reception signal of the own vehicle 110. [ When the radar transmission signal of the other vehicle 120 has a short period on the time axis as compared with the radar transmission signal of the own vehicle 110, the own vehicle 110 receives the repetitive periodic interference signal within one period And adversely affect target signal detection.

Further, when a vehicle passes through a steel tunnel or the like, a reflected signal reflected by a plurality of steel tunnel structures may be received as a received signal, which may adversely affect target detection. For example, in a circumstance where a plurality of steel structures with high reflectance for a transmission signal are arranged at a predetermined interval, a plurality of interference signals are reflected and transmitted to the steel structure, and the target signal detection performance may be degraded.

Specifically, when an interference signal is received in the received signal, the frequency spectrum 150 of the received signal includes a plurality of interfering signal components. It may be difficult to detect the target signal component 160 by the target object due to a large number of interference signal components. That is, since the magnitude of the interference signal component excluding the target signal component 160 is calculated to be large, the detection performance of the target signal component 160 may be degraded or distortion may occur.

In this embodiment, a target object detection device for solving such a problem will be described.

2 is a block diagram of a target object detection apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the target object detection apparatus 200 includes a signal transmission unit 210 for transmitting a transmission signal for detecting a target object. The transmitted signal may refer to an RF signal having a frequency band for a radar signal. The target object sensing apparatus 200 can transmit or continuously transmit a transmission signal to a vehicle ahead or to a vehicle periphery to detect a target object.

In addition, the target object sensing apparatus 200 includes a signal receiving unit 220 that receives a reception signal including a target signal generated by reflecting a transmission signal on a target object. The reception unit 220 receives a reception signal that is reflected by an object generating the various reflected waves of the target or the surroundings and received by the reception antenna. In addition, the received signal may include an interference signal, a noise signal, and the like. The target object sensing apparatus 200 may transmit a transmission signal for a predetermined period or continuously and sense a target object using a reception signal that is a reflection signal of the transmission signal. The target object sensing apparatus 200 in the present embodiment may be a radar apparatus using various transmission and reception signals and is not limited by the type of transmission signal or reception signal and the signal transmission / reception method. Hereinafter, for convenience of explanation, it is assumed that a forward looking FMCW radar for 77 GHz long-range (for example, a long distance FMCW radar for forward surveillance) is assumed.

The target object detection apparatus 200 includes a signal analysis unit 230 for calculating frequency spectrum information of a received signal and extracting periodicity information for confirming the periodicity of the frequency spectrum information. The signal analyzer 230 calculates the frequency spectrum information of the received signal. The frequency spectrum information can be calculated through Fourier transform of the received signal. In this case, a number of interference signal components may exist as indicated by reference numeral 150 in FIG. The signal analyzer 230 may extract the periodicity information using the calculated frequency spectrum information. For example, the signal analyzer 230 can extract periodicity information by performing fast Fourier transform (FFT) on frequency spectrum information. As another example, the signal analyzer 230 may calculate the binary frequency spectrum information using the frequency spectrum information and the binary reference value, and extract the periodicity information by performing fast Fourier transform (FFT) on the calculated binary frequency spectrum information . As another example, the signal analyzer 230 may calculate the binary peak frequency spectrum information using the frequency spectrum information and the binary reference value, perform fast Fourier transform (FFT) on the calculated binary peak frequency spectrum information, Can be extracted. As another example, the signal analyzer 230 may extract periodicity information by performing inverse fast Fourier transform (IFFT) on the frequency spectrum information. As another example, the signal analyzer 230 may extract the periodicity information by performing fast Fourier transform on the frequency spectrum information after taking a log. As another example, the signal analyzer 230 may extract periodicity information by performing inverse fast Fourier transform (IFFT) on the frequency spectrum information after taking a log. That is, the signal analyzer 230 can obtain a Cepstrum of the received signal and use it to check periodicity information. As another example, the signal analyzer 230 may extract periodicity information by performing a fast Fourier transform or an inverse fast Fourier transform (IFFT) after squaring the magnitude of the frequency spectrum information. That is, the signal analyzer 230 can obtain the auto-correlation of the received signal and use it for checking the periodicity information. In addition, the signal analyzer 230 may extract the periodic information of the frequency spectrum by changing the frequency spectral information to another domain. Various methods such as the FFT, the binary FFT, and the IFFT described above can be used for changing to another domain, and the method is not limited to the specific method. Hereinafter, some of the above-described periodic information extraction methods will be mainly described for convenience of understanding, but these are for convenience of understanding, and each of the embodiments described above may be performed in the same manner.

In addition, the target object sensing apparatus 200 includes a determination unit 240 that determines whether an interference signal is included in the received signal based on the periodicity information. The determination unit 240 may determine whether an interference signal exists in the received signal using the peak value component of the periodicity information. For example, when the peak value component exists in the periodicity information, the determination unit 240 may determine that the received signal includes an interference signal that generates the corresponding peak value component. Alternatively, the determination unit 240 may determine that the interference signal is included when the peak value components included in the periodicity information appear at regular intervals.

Meanwhile, when the peak value component of the periodicity information is detected, the determination unit 240 may classify the type of the interference signal included in the received signal using the band information in which the corresponding peak value component is detected. For example, when the peak value component detected in the periodicity information is detected in a band lower than a preset band reference value, it can be determined that the received signal includes an interference signal generated by another radar signal. On the contrary, when the peak value component detected in the periodicity information is detected in a band exceeding a predetermined band reference value, it may be determined that the clutter signal is included in the received signal as an interference signal. Alternatively, when the peak value components included in the periodicity information appear at regular intervals, the determination unit 240 may determine that the clutter signal due to the clutter structure is included in the received signal as an interference signal. Therefore, the determination unit 240 can confirm the periodic expression of the peak value component that is not confirmed in the frequency spectrum information by using the periodicity information, and can determine that the interference signal is included in the received signal by using the periodicity information.

In addition, the target object detection apparatus 200 includes a target detection unit 250 for removing an interference signal and extracting a target signal. The target detector 250 may suppress the peak value component of the periodicity information when it is determined that the interference signal exists based on the periodicity information. Here, in order to suppress the peak value component of the periodicity information, the corresponding component may be removed (set to zero), or the value of the corresponding component may be changed using an interpolation method. Or a smoothing filter may be used to change the value of the component to be suppressed. The above-described suppression method is merely illustrative and various methods for changing the peak value of the periodicity information to suppress the peak value component can be applied, and there is no limitation thereto. Thereafter, the target detector 250 may detect the target object by converting periodic information whose peak value component is suppressed to frequency spectrum information. The target detector 250 may convert the periodicity information into the frequency spectrum information in the reverse of the method of converting the frequency spectrum information into the periodicity information. For example, the target detector 250 may convert the periodic information suppressing the peak value component to a frequency spectrum by FFT or IFFT. As another example, the target detector 250 may IFFT the periodic information suppressing the peak value component and multiply it by the existing frequency spectrum to convert it into a frequency spectrum. As another example, the target detector 250 may perform FFT on the periodicity information suppressing the peak value component and convert the periodicity information into a frequency spectrum. In addition, the target detector 250 may apply various methods to convert the domain of the periodicity information into the frequency domain.

The target detector 250 can detect the target object using the converted frequency spectrum information converted to the frequency spectrum after the peak value is suppressed in the periodicity information. In this case, since the peak value component is suppressed in the periodicity information, the peak component due to the interference signal in the frequency spectrum is significantly reduced, and the detection of the target signal becomes easier. Therefore, the target detector 250 can easily detect the target signal through the transformed frequency spectrum analysis after suppressing the peak value component of the periodic information even in a situation where it is difficult to detect the target signal using the frequency spectrum of the received signal.

In addition, the target detector 250 may dynamically adjust a parameter for detecting a target signal using a result of discriminating whether the interference signal is generated by another radar signal or by a clutter structure in the determiner 240 . For example, a reference value for detecting a target signal may be previously set in accordance with the type of the interference signal, and if the type of the interference signal is determined, the reference value may be applied differently according to the interference signal. In addition, parameters for target signal detection can be variously set in advance, and the parameters can be changed dynamically according to the types of interference signals.

Hereinafter, a target object sensing apparatus according to the present embodiment will be described in detail with reference to the drawings.

3 is a diagram illustrating exemplary periodic information extracted through Fast Fourier Transform according to an embodiment.

Referring to FIG. 3, the received signal received by the target object detection apparatus may include at least one of a noise signal, an interference signal, and a target signal according to a situation. The signal analyzer converts the received signal into a frequency domain to calculate the frequency spectrum information 300. The frequency spectrum information 300 may include an interference signal, a noise signal, and a frequency component according to a target signal. Therefore, when the interference signal is included, a plurality of peak value components may be included in the frequency spectrum information 300, thereby making it difficult to detect the peak value component by the target signal.

For example, in the case of an FMCW radar, a method of calculating frequency spectrum information using a received signal is as follows.

The signal for each channel transmitted by the FMCW radar and reflected by the L objects can be defined as Equation (1).

A _k (i) is the amplitude of the signal reflected on each object. f (i) is the sum or difference of f _r (i), which is the difference between the frequencies due to the distance of the object, and f _d (i), which is the difference between the frequencies caused by the relative speed, . f (i) can be determined as the sum or difference of f _r (i) and f _d (i) depending on the up-chirp or down-chirp of the signal.

Where B is the bandwidth, T is the duration of the chirp, c is the speed of light, f _c is the center frequency, R (i) and V _r (i) And relative speed. Also, φ _k (i) is the phase component of each received signal for each channel

S _k (n) is the discrete-time (discrete-time) signal of S _k (t)

Where n is the discrete-time index of the received signal during a single scan and N is the total number of samples of the received signal during a single scan.

The short-time Fourier transform (STFT) or FFT of the received signal can be expressed as Equation (5).

Where f is the frequency index and m is the scan index.

The magnitude response (size response) plus the frequency domain signal for each receiving channel can be obtained as shown in Equation (6).

As described above, the signal analyzer can calculate the frequency spectrum information using the received signal. Although the example of calculating the frequency spectrum information is described above, various frequency related response information such as frequency response information can be calculated. There is no limitation on the method of calculating the frequency spectrum information.

The signal analyzer can calculate the periodicity information 310 using the frequency spectrum information 300 calculated by the above method. In the present embodiments, the X axis and the Y axis of the periodicity information are represented by indices and sizes, respectively, and the units may be variously changed according to a signal processing method for extracting the periodicity information. For example, the periodicity information 310 extracted by FFT of the frequency spectrum information 300 includes a plurality of peak value components. The signal analyzing unit extracts the periodicity information 310 using the frequency spectrum 300. The determining unit 310 determines at least one of the presence or absence of the peak value component of the periodicity information 310 and the detection form of the peak value component and the detection position of the peak value component It is possible to check whether the interference signal is contained in the received signal by using one. Alternatively, the determination unit may determine a cause of the interference signal included in the received signal (for example, an interference signal type).

In the above description, a method of using FFT to extract periodicity information using a frequency spectrum of a received signal of a signal analysis unit has been mainly described. Hereinafter, various methods for extracting periodicity information will be described with reference to FIGS. .

4 is a diagram illustrating an example of a binary frequency spectrum according to an exemplary embodiment of the present invention. 5 is a diagram exemplarily showing periodicity information extracted using a binary frequency spectrum according to an exemplary embodiment.

Referring to FIG. 4, the signal analyzer may calculate frequency spectrum information 400 for a received signal. When the interference signal is included in the received signal, the frequency spectrum information 400 includes a plurality of peak value components, and detection of the target signal component 401 may be difficult. To solve this problem, the signal analyzer can calculate the periodicity information using the frequency spectrum information.

For example, the signal analyzing unit may calculate the binary frequency spectrum information 410 obtained by converting the frequency spectrum information 400 to a value of 0 or 1 on the basis of a predetermined binary reference value, and may convert the binary frequency spectrum information 410 into a fast Fourier transform (fast Fourier transform (FFT)) to extract periodicity information. Specifically, the signal analyzing unit converts the frequency component equal to or higher than the binary reference value to 1 using the frequency spectrum information 400 and the preset binary reference value, and outputs the binary frequency spectrum information 410 obtained by converting the frequency component lower than the binary reference value to 0 Can be generated. Reference numeral 410 denotes an example in which the frequency spectrum information 400 is binarized using a binary reference value of 10,000. The signal analysis unit may extract the periodicity information by performing FFT on the binary frequency spectrum information 410. [

Referring to FIG. 5, the signal analyzer can confirm the periodicity information 500 obtained by FFTing the binary frequency spectrum information 410 shown in FIG. In this case, when the frequency spectrum information 400 is binarized to 0 and 1, the peak value components 501, 502, 503, 504, 505, and 506 in the periodicity information 500 are confirmed easy. The target object detection apparatus uses the peak value components 501, 502, 503, 504, 505, and 506 of the periodicity information 500 to determine whether an interference signal exists.

FIG. 6 is a diagram illustrating a binary peak frequency spectrum according to an exemplary embodiment. Referring to FIG. FIG. 7 is a diagram illustrating exemplary periodic information extracted using a binary peak frequency spectrum according to an exemplary embodiment. Referring to FIG.

The signal analyzer calculates binary peak frequency spectrum information obtained by converting a peak component of the frequency spectrum information into a value of 0 or 1 on the basis of a predetermined binary reference value and outputs the binary peak frequency spectrum information to a fast Fourier transform FFT) to extract the periodicity information.

Referring to FIG. 6, the signal analyzer can calculate the binary peak frequency spectrum information 600 by converting the frequency spectrum information 400 in FIG. 4 into 0 and 1 values according to the binary reference value and the peak. For example, the signal analyzer may compare the binary reference value in the frequency spectrum information 400 and convert it to 1 only for the peak component among components having a size larger than the binary reference value. The value of the peak component having a magnitude less than the binary reference value can be converted to zero. In addition, all values other than the peak of the frequency spectrum information 400 can be converted to zero. In this case, the number of indexes having a value of 1 can be reduced in comparison with the binary frequency spectrum information 410 in FIG. FIG. 6 shows an example in which the frequency spectral information 400 of FIG. 4 is binarized with respect to a peak component by using a binary reference value of 10,000.

Referring to FIG. 7, the signal analyzer may extract the periodicity information 700 by performing FFT on the binary peak frequency spectrum information 600 shown in FIG. The periodicity information 700 extracted by performing the FFT on the binary peak frequency spectrum information 600 can confirm that the peak value components 701, 702, 703, 704, 705, and 706 are periodically generated within a predetermined interval. The determination unit determines that the interference signal is included in the received signal using the presence or absence of the peak value components 701, 702, 703, 704, 705, and 706 of the periodicity information 700 or periodically within a predetermined interval It can be judged.

FIG. 8 is an exemplary diagram illustrating periodicity information extracted through inverse fast Fourier transform according to an embodiment.

The signal analyzer may extract periodicity information by inverse fast Fourier transform (IFFT) of the frequency spectrum information.

Referring to FIG. 8, the signal analyzer may IFFT the frequency spectrum information to extract periodicity information 800. For example, the signal analyzing unit can extract the periodicity information 800 by FFTing the received signal and obtaining a magnitude response (magnitude response) by performing IFFT on the frequency spectrum information obtained from the magnitude response (magnitude response). In this case, it is also confirmed that the peak value components 801, 802, 803, 804, 805, and 806 are extracted in the periodicity information 800 and periodically appear within a predetermined interval.

As described above, the signal analyzer can extract the periodicity information using various signal processing methods based on the frequency spectrum information of the received signal.

The target object detection apparatus in this embodiment can determine whether or not an interference signal exists based on the periodicity information. For this, the determination unit may use the peak value component of the periodicity information.

For example, the determination unit may determine that the interference signal is included in the received signal if the peak value component exceeding the preset reference value exists in the periodicity information. Alternatively, the determination unit may determine that the interference signal is included when the peak value components exceeding the preset reference value are periodically detected at predetermined intervals in the periodicity information.

FIG. 9 is a diagram for explaining an operation for classifying an interference signal type according to an embodiment.

If necessary, the determination unit may determine the type of the interference signal using the peak value component extracted from the periodicity information. For example, the determination unit may classify the type of the interference signal based on the band information in which the peak value component of the periodicity information is detected. Alternatively, the determination unit may classify the type of the interference signal by using whether the peak value component of the periodicity information is periodically detected within a predetermined predetermined interval.

9, when a peak value component of the periodicity information 900 extracted by the signal analysis unit is detected at a predetermined band reference value 905 or less, the interference signal included in the received signal is transmitted to another radar It can be judged that it is generated by the signal. Alternatively, when the peak value component of the periodicity information 910 extracted by the signal analysis unit is detected at a predetermined band reference value 905 or more, the interference signal included in the received signal is generated by the clutter structure . That is, the determination unit can classify the type of the interference signal based on the position where the peak value component of the periodicity information occurs.

On the other hand, when the peak value component of the periodicity information periodically occurs within a predetermined interval, the determination unit may determine that an interference signal due to the clutter structure exists. For example, when the periodicity information is extracted, the determination unit can check whether the peak value component in the extracted periodicity information is generated within a predetermined interval to check whether the clutter signal is present. That is, when the peak value component of the periodicity information exists within a predetermined interval, it can be determined that the clutter signal is included in the received signal and the clutter structure exists. On the contrary, if there is no peak value component that appears relatively large in the periodicity information as compared with the surrounding value, or if the peak value component does not exist periodically within a predetermined interval, it is determined that the interference signal generated by the clutter signal does not exist .

For example, the periodicity information may include a peak value component periodically generated within a predetermined interval, and may determine that a clutter signal is included in the received signal when a periodically generated peak value component exists have. However, the peak value components in the periodicity information may not be generated at the same intervals, so that it can be determined that the peak value components are generated periodically in the case where the peak value component exists within the preset constant interval range. The peak value in the periodicity information can be extracted by extracting only peaks exceeding a preset reference value or comparing the average value of the surrounding size values with a peak that is larger than a predetermined size. That is, it is possible to extract a peak value exceeding a predetermined reference value as a peak value for periodicity confirmation, and determine whether the peak value occurs periodically. Alternatively, it is possible to compare the average of the surrounding peak values with the magnitudes of the respective peak values, extract peak values having a magnitude difference greater than a predetermined value, and determine whether the corresponding peak value occurs periodically.

Since the periodicity information 900 and 910 described above are calculated in a bilaterally symmetrical form on the basis of the index, the determination unit can determine based on only a part of the symmetric shape to determine the type of the interference signal.

As described above, the target object detection apparatus extracts the periodicity information by various methods using the frequency spectrum information of the received signal, and detects the existence of the interference signal or the type of the interference signal using the peak value component of the extracted periodicity information Can be confirmed.

10 is a diagram exemplarily showing a spectrum suppressing a peak value component in periodicity information according to an embodiment.

The target detection unit of the present embodiment can suppress the peak value component equal to or higher than the predetermined peak reference value in the periodicity information and convert the periodicity information with the peak value component into the converted frequency spectrum information to extract the target signal reflected by the target object .

Referring to FIG. 10, the target detector may calculate the periodicity information 1000 in which the peak value component is suppressed by suppressing the peak value component periodically generated in the periodicity information. The target detector may calculate the periodicity information 1000 in which the peak value component is suppressed by changing the peak value selected for periodicity confirmation to 0 in the periodicity information. Alternatively, the target detector may suppress the peak value component by changing the peak value selected for the periodicity check to the size of the surrounding index or by changing the average value of the surrounding index. In FIG. 10, the peak value component of the periodicity information 310 shown in FIG. 3 is converted into 0, and the periodicity information 1000 in which the peak value component is suppressed is calculated. Thus, the target detector can suppress the frequency component generated by the interference signal by suppressing the peak value component in the periodicity information.

11 is a view for explaining a converted frequency spectrum after suppressing a peak value component according to an embodiment.

Referring to FIG. 11, the target detector may extract the target signal component 1110 from the target object by converting the periodicity information into the converted frequency spectrum information 1100 after suppressing the peak value component in the periodicity information. In this case, the method of converting the periodicity information in which the peak value component is suppressed to the converted frequency spectrum may vary depending on the method of extracting the periodicity information.

For example, when the periodicity information is extracted by performing FFT on the frequency spectrum information, the target detector may calculate the converted frequency spectrum information 1100 by performing IFFT on the periodicity information on which the peak value component is suppressed. In this case, since the converted frequency spectrum information suppresses the peak value component in the periodicity information, it differs from the frequency spectrum information calculated using the received signal. That is, the target signal in the initial frequency spectrum information has a problem that detection is difficult due to a plurality of clutter signals. However, in the converted frequency spectrum information 1100, it is confirmed that the peak value component suppressed in the periodicity information makes it easier to detect the peak 1110 of the target signal. Thus, the present invention provides the effect of facilitating detection of a target signal in the presence of an interfering signal.

As another example, when the periodicity information is extracted using the binary frequency spectrum information, the target detecting unit performs IFFT on the periodicity information in which the peak value component is suppressed, and then weights the initial frequency spectrum information to obtain the converted frequency spectrum information 1100. [ Can be calculated. Specifically, the target detector may suppress the peak value component in the extracted periodicity information using the binary frequency spectrum information, and perform the IFFT using the periodicity information in which the peak value component is suppressed. Thereafter, the transformed frequency spectrum information 1100 can be calculated by multiplying the IFFT-performed spectrum by the original frequency spectrum generated using the received signal to compensate for the binary value. The peak 1110 of the target signal in the converted frequency spectrum information 1100 is more clearly detected.

As another example, when the periodic information is extracted using the binary peak frequency spectrum information, the target detector performs IFFT on the periodic information in which the peak value component is suppressed, and then weights the initial frequency spectrum information to obtain converted frequency spectrum information 1100). As in the case of using the above-described binary frequency spectrum, the target detector can suppress the peak value component in the extracted periodicity information using the binary peak frequency spectrum information and perform the IFFT using the periodicity information in which the peak value component is suppressed have. Thereafter, the transformed frequency spectrum information 1100 can be calculated by multiplying the IFFT-performed spectrum by the original frequency spectrum generated using the received signal to compensate for the binary value.

As another example, when the periodicity information is extracted by performing IFFT on the frequency spectrum information, the target detector may calculate the converted frequency spectrum information 1100 by performing FFT or IFFT on the periodicity information on which the peak value component is suppressed. Specifically, the target detector may IFFT the frequency spectrum information, suppress the peak value component in the extracted periodicity information, and perform the FFT or IFFT using the periodicity information with the peak value component suppressed. The target detecting unit can detect the target object using the target signal peak 1110 in the converted frequency spectrum information 1100 calculated through this process.

As described above, the target detector can detect the target signal more easily than the initial frequency spectrum by suppressing the peak value component periodically generated in the periodicity information and converting it into the frequency domain. That is, even when the clutter signal is included, the target signal can be easily detected.

Meanwhile, the target detector may detect the target signal using the initial frequency spectrum information or the converted frequency spectrum information and the detection threshold value. The target detection unit can use detection threshold information to detect a target signal from a noise signal or the like. That is, when the detection threshold value is set and the signal strength of each frequency exceeds the detection threshold value, it can be detected as a target signal, not a noise.

However, when an interference signal exists as in the present invention, it may be difficult to detect the target object when the target signal is detected to be smaller than the interference signal. If it is determined that the interference signal is present, the target detection unit can detect the target object by adjusting the detection threshold value so that the target signal is detected. The detection threshold value in the present invention may be a fixed value, a value changed by setting, or a value calculated dynamically in consideration of the intensity of the surrounding frequency and the like.

The target detection unit can detect the final target object using an adaptive algorithm that corrects the detection threshold and detects the target. For example, an adaptive algorithm for detecting a target may use a Constant false alarm rate (CFAR). In addition, it detects target objects in response to background noise such as noise, clutter, or interference from a received signal Various algorithms may be used.

The target detection unit of the present invention can correct the detection threshold calculation parameter such that, when it is determined that the interference signal exists, the detection threshold value is lowered in calculating the detection threshold value for target object detection. Further, the detection threshold value calculation parameter can be configured differently depending on the type of the interference signal.

The presence or absence of the interference signal is checked according to the determination result of the determination unit, and if it is confirmed that the interference signal does not exist, the target signal is detected using the preset detection threshold value. If it is confirmed that an interference signal exists, the parameter correction for adjusting the detection threshold value can be performed. Thereafter, the target detection unit may calculate the detection threshold value using the corrected parameter. The detection threshold value may be calculated using various algorithms for detecting the target signal when the target signal is received with an intensity equal to or higher than the detection threshold value for noise removal or the like. For example, in the CFAR algorithm or the like for determining the detection threshold value using the intensity information of the surrounding frequency, the parameter for determining the detection threshold value may be corrected to a predetermined value to lower the detection threshold value. This makes it possible to detect the target signal even if the interference signal is strongly received.

On the other hand, the target detector can detect the peak signal exceeding the threshold value using the determined detection threshold value. In this case, the detection threshold value may be lower than the target signal, and thus the target signal and the interference signal can be partially detected.

The target detecting unit may detect the final target object using the detected one or more peak signals. For example, when the target object is a moving vehicle and the interference signal is a clutter signal, the clutter signal is a fixed object that is generated by an iron tunnel or the like. Therefore, the target object which is the final moving object can be detected through an algorithm such as filtering the detected peak signal. As another example, when the target object is an object traveling in the same direction as the vehicle, and the interference signal is a signal generated by another radar, the interference signal is in a direction opposite to the moving direction of the target object. The target object may be detected.

Hereinafter, a method of detecting a target object according to an embodiment of the present invention described with reference to FIGS. 1 to 11 will be briefly described again.

12 is a flowchart illustrating a method of detecting a target object according to an embodiment.

A method of detecting a target object according to an exemplary embodiment includes a signal transmitting step of transmitting a transmission signal for detecting a target object, a signal receiving step of receiving a reception signal including a target signal generated by reflecting a transmission signal on a target object, A signal analysis step of calculating frequency spectrum information of the frequency spectrum information and extracting periodicity information for confirming the periodicity of the frequency spectrum information, a determination step of determining whether an interference signal is included in the received signal based on the periodicity information, And a target detection step of extracting a target signal.

Referring to FIG. 12, the target object detection method includes a signal transmission step of transmitting a transmission signal for detecting a target object (S1200). The transmitted signal may refer to an RF signal having a frequency band for a radar signal.

In addition, the target object detection method includes a signal reception step of receiving a reception signal including a target signal generated by reflecting a transmission signal on a target object (S1210). The receiving step receives the received signal, which is reflected by an object generating the various reflected waves of the target or the surroundings, and the received signal is received by the receiving antenna. In addition, the received signal may include an interference signal, a noise signal, and the like.

In addition, the target object detection method includes a signal analysis step of calculating frequency spectrum information of the received signal and extracting periodicity information for confirming the periodicity of the frequency spectrum information (S1220). The signal analysis step calculates the frequency spectrum information of the received signal. The frequency spectrum information can be calculated through Fourier transform of the received signal. The signal analysis step can extract the periodicity information using the calculated frequency spectrum information. For example, the signal analysis step can extract the periodicity information by performing fast Fourier transform on the frequency spectrum information. As another example, the signal analysis step may calculate the binary frequency spectrum information using the frequency spectrum information and the binary reference value, and extract the periodicity information by fast Fourier transforming the calculated binary frequency spectrum information. As another example, the signal analysis step may calculate the binary peak frequency spectrum information using the frequency spectrum information and the binary reference value, and extract the periodicity information by fast Fourier transforming the calculated binary peak frequency spectrum information. As another example, the signal analysis step may extract periodicity information by inverse fast Fourier transforming the frequency spectrum information. As another example, the signal analysis step may extract the periodicity information by performing a fast Fourier transform on a log of the frequency spectrum information. That is, the signal analysis step can obtain a cepstrum of the received signal and use it to check the periodicity information.

In addition, the target object detection method includes a determination step of determining whether an interference signal is included in the received signal based on the periodicity information (S1230). The determining step may determine whether an interference signal exists in the received signal using the peak value component of the periodicity information. For example, if the peak value component exists in the periodicity information, the determination step may determine that the received signal includes an interference signal that generates the peak value component. Or the determination step may determine that the interference signal is included when the peak value components included in the periodicity information appear at regular intervals.

Meanwhile, when the peak value component of the periodicity information is detected, the determination step may classify the type of the interference signal included in the received signal using the band information in which the corresponding peak value component is detected. For example, when the peak value component detected in the periodicity information is detected in a band lower than a preset band reference value, it can be determined that the received signal includes an interference signal generated by another radar signal. On the contrary, when the peak value component detected in the periodicity information is detected in a band exceeding a preset band reference value, it may be determined that the clutter signal is included in the received signal as an interference signal. Alternatively, when the peak value components included in the periodicity information appear at regular intervals, the determination step may determine that the clutter signal due to the clutter structure is included in the received signal as an interference signal.

In addition, the target object detection method includes a target detection step of removing an interference signal and extracting a target signal (S1240). The target detecting step may suppress the peak value component of the periodicity information when it is determined that the interference signal exists based on the periodicity information. Thereafter, the target detection step may detect the target object by converting periodic information whose peak value component is suppressed to converted frequency spectrum information. As described above, the method of converting the periodicity information into the converted frequency spectrum information in the target detecting step may be performed in the reverse of the method of converting the frequency spectrum information into the periodicity information.

The target detection step may detect the target object using the converted frequency spectrum information converted into the frequency spectrum after the peak value component is suppressed in the periodicity information. In this case, since the peak value component is suppressed in the periodicity information, the peak component due to the interference signal in the frequency spectrum is significantly reduced, and the detection of the target signal becomes easier.

In addition, the target detection step can dynamically adjust a parameter for detecting a target signal using a result of discriminating whether an interference signal is generated by another radar signal or a clutter structure in a determination step. For example, the threshold reference value for detecting a target signal may be determined in advance according to the kind of the interference signal, and if the type of the interference signal is determined, the threshold reference value may be applied differently according to the interference signal. In addition, parameters for target signal detection can be variously set in advance, and the parameters can be changed dynamically according to the types of interference signals.

As described above, according to the present embodiment, there is an effect that the target object detection performance can be improved by effectively removing the interference signal by analyzing the received signal acquired by the target object detection device. Also, according to the present embodiment, the target object detection performance can be improved even in an environment where various interference signals exist by classifying the types of the interference signals and adjusting the target detection parameters accordingly.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (18)

A signal transmitter for transmitting a transmission signal for detecting a target object;
A signal receiver for receiving a reception signal including a target signal generated by reflecting the transmission signal on the target object;
A signal analyzer for calculating frequency spectrum information of the received signal and extracting periodicity information for confirming the periodicity of the frequency spectrum information;
A determination unit for determining whether an interference signal is included in the received signal based on the periodicity information; And
And a target detection unit for suppressing the interference signal and extracting the target signal. The method according to claim 1,
Wherein the signal analyzer comprises:
Wherein the periodic information is extracted by a fast Fourier transform (FFT) or an inverse fast Fourier transform (IFFT) of the frequency spectrum information. The method according to claim 1,
Wherein the signal analyzer comprises:
Calculating binary frequency spectrum information in which the frequency spectrum information is converted into a value of 0 or 1 on the basis of a predetermined binary reference value, and extracting the periodicity information by performing fast Fourier transform (FFT) on the binary frequency spectrum information Wherein the target object detecting device detects the target object. The method according to claim 1,
Wherein the signal analyzer comprises:
Calculating binary peak frequency spectrum information obtained by converting a peak component of the frequency spectrum information into a value of 0 or 1 on the basis of a predetermined binary reference value and outputting the binary peak frequency spectrum information by a fast Fourier transform And extracts the periodicity information. The method according to claim 1,
Wherein the signal analyzer comprises:
The frequency spectrum information is converted into a log scale, and the frequency spectrum information converted into the log scale is subjected to fast Fourier transform (FFT) or inverse fast Fourier transform (IFFT) to extract the periodicity information Wherein the target object detecting device detects the target object. The method according to claim 1,
Wherein the signal analyzer comprises:
And the periodicity information is extracted by performing a fast Fourier transform (FFT) or an inverse fast Fourier transform (IFFT) on the magnitude component of the frequency spectrum information, . The method according to claim 1,
Wherein,
Wherein the presence or absence of the interference signal is determined using the peak value component of the periodicity information. The method according to claim 1,
Wherein,
And classifies the type of the interference signal included in the received signal by using the band information in which the peak value component of the periodicity information is detected. 9. The method of claim 8,
Wherein,
When the peak value component of the periodicity information is detected at a predetermined band reference value or less, it is determined that the interference signal is generated by the radar,
Wherein when the peak value component of the periodic information is detected at a predetermined band reference value or more, it is determined that the interference signal is generated by the clutter structure. The method according to claim 1,
Wherein the target detecting unit comprises:
Wherein the target signal is detected by suppressing a peak value component equal to or higher than a predetermined peak reference value in the periodicity information and converting the periodicity information in which the peak value component is suppressed to converted frequency spectrum information. The method according to claim 1,
Wherein the target detecting unit comprises:
Suppressing the first peak value component when the difference between the first peak value located before and after the first peak value and the first peak value is equal to or greater than a reference value based on the first peak value included in the periodicity information, Converting the information into converted frequency spectrum information, and extracting a target signal reflected by the target object. The method according to claim 1,
The shopping target detecting unit,
And a parameter for detecting the target signal is separately applied according to the type of the interference signal. A signal transmission step of transmitting a transmission signal for detecting a target object;
A signal receiving step of receiving a reception signal including a target signal generated by reflecting the transmission signal on the target object;
A signal analysis step of calculating frequency spectrum information of the received signal and extracting periodicity information for confirming the periodicity of the frequency spectrum information;
Determining whether an interference signal is included in the received signal based on the periodicity information; And
And a target detecting step of suppressing the interference signal and extracting the target signal. 14. The method of claim 13,
Wherein the signal analysis step comprises:
Wherein the periodic information is extracted by performing fast Fourier transform (FFT) or inverse fast Fourier transform (IFFT) on the frequency spectrum information. 14. The method of claim 13,
Wherein,
Wherein the presence or absence of the interference signal is determined using the peak value component of the periodicity information. 14. The method of claim 13,
Wherein,
And classifying the type of the interference signal included in the received signal by using the band information in which the peak value component of the periodicity information is detected. 14. The method of claim 13,
The target detecting step may include:
Wherein the target signal is detected by suppressing a peak value component equal to or higher than a predetermined peak reference value in the periodicity information and converting the periodicity information in which the peak value component is suppressed to converted frequency spectrum information. 14. The method of claim 13,
The dwelling target detecting step includes:
Wherein a parameter for detecting the target signal is separately applied according to the type of the interference signal.

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