KR101792114B1 - Method of detecting object and measuring distance with rader in complicated circumstances - Google Patents

Method of detecting object and measuring distance with rader in complicated circumstances Download PDF

Info

Publication number
KR101792114B1
KR101792114B1 KR1020150092619A KR20150092619A KR101792114B1 KR 101792114 B1 KR101792114 B1 KR 101792114B1 KR 1020150092619 A KR1020150092619 A KR 1020150092619A KR 20150092619 A KR20150092619 A KR 20150092619A KR 101792114 B1 KR101792114 B1 KR 101792114B1
Authority
KR
South Korea
Prior art keywords
signal
clutter
distance
radar
information
Prior art date
Application number
KR1020150092619A
Other languages
Korean (ko)
Other versions
KR20170002816A (en
Inventor
차상희
Original Assignee
비아이에스웍스 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 비아이에스웍스 주식회사 filed Critical 비아이에스웍스 주식회사
Priority to KR1020150092619A priority Critical patent/KR101792114B1/en
Publication of KR20170002816A publication Critical patent/KR20170002816A/en
Application granted granted Critical
Publication of KR101792114B1 publication Critical patent/KR101792114B1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
    • G01S7/4021—Means for monitoring or calibrating of parts of a radar system of receivers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/0218—Very long range radars, e.g. surface wave radar, over-the-horizon or ionospheric propagation systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/04—Systems determining presence of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The present invention eliminates a shadow effect that is mistakenly detected as a motion of fixed objects around a sensing object when detecting an object through the radar and a distance measurement, or a multipath phenomenon in which a signal reflected by the sensing object is reflected by another object We propose a method to accurately detect the object and measure the distance.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for detecting objects in a complex situation using a radar,

The present invention relates to an object detecting method and a distance measuring method in a complex situation using a radar, and more particularly, to an object detecting method and a distance measuring method which detect a shadow effect or a shadow The present invention relates to a method of detecting a multi-path phenomenon in which a signal reflected by an object is reflected by another object, thereby detecting the object more accurately and measuring the distance.

A radar is a device that measures the direction of an object and its direction and distance by detecting the reflected wave reflected from the object by using the directivity of the radio wave and measuring the time until the received time.

For example, FIG. 1 shows a schematic diagram of an ultra-wide band radar (UWB). A typical UWB radar 50 propagates an UWB signal through a transmission antenna 51, The receiving antenna 55 receives a reflected wave that is reflected by the moving object 10 or the fixed object 30 and returns. The received signal is sampled, the object is detected based on the change of the received signal with respect to the transmitted signal, and the distance is measured through the time when the propagated signal is received.

2 shows a schematic flow chart of a method for detecting and measuring an object of a radar according to the prior art.

Generally, when a radar transmits a transmission signal (S10) and receives a reflected wave signal (S30), it removes a reflection obstacle clutter (echo) due to unnecessary reflected waves from the received signal (S50) (S70) and calculates a distance to the sensed object (S90). At this time, a clutter map is generated to remove the clutter, and the clutter-removed detection signal is extracted by reflecting the clutter map on the received signal.

In the case of object detection and distance measurement using such a radar, a shadow effect or an error due to a multipath phenomenon occurs, and a shadow effect and a multipath phenomenon will be briefly described.

First, the shadow effect is a phenomenon similar to the shadow we are experiencing in everyday life. In the radar measurement, a shielded area is generated from the radar irradiation by the interventional medium or absorption medium that affects the object, The area without target or the actual object is distorted.

3, in a situation where the bookcase 33 is placed in a space without a moving object as shown in FIG. 3A, the reflected wave signal 41 for the bookcase is received almost constantly, and the bookcase 33 Can be detected.

3 (b), the signal 42 to the desk 33 disappears due to intervention reflection or absorption of the radar wave of the moving object 13, The desk 33 does not appear on the radar indicator.

When the clutter is removed using the clutter map, signals are detected at two positions as shown in FIG. 3 (c), and in addition to the signals 43 for the two moving objects, that is, the actual moving object 13, A signal 44 appears, which is called a shadow effect.

Next, the multipath phenomenon is a phenomenon in which multiple signals appear on a moving object. As the reflected wave from the object is reflected on another object and reaches the radar, the propagation of different paths to the object is received by the radar It says.

4, when an object such as the wall 35 exists in the vicinity of the moving object 15 as shown in FIG. 4 (a), the reflected signal from the moving object 15 travels in various directions And reflected by the wall 35 and received by the radar.

In this case, as shown in FIG. 4 (b), the multipath signal 46 reflected by the wall 35 after the signal 45 by the actual moving object 15 is received, Two are recognized.

In the case of such a conventional radar, a shadow effect or a multipath phenomenon occurs in a complex situation in which a moving object and a fixed object are mixed together, thereby causing confusion in detecting the object to be detected, There is a problem that an error occurs in measurement of

Conventionally, there have been proposed various methods for eliminating such errors in the object detection and distance measuring technology using radar, but the conventional techniques have not been able to properly remove errors due to shadow effect or multipath phenomenon In order to compensate for such errors, there are various problems that are difficult to remove errors in a practically appropriate manner, such as a large-sized equipment and a rapid increase in the manufacturing cost of the equipment itself.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a radar apparatus and a radar apparatus capable of generating a shadow effect or a multipath phenomenon in a complex situation in which a moving object and a fixed object are mixed together, So as to solve the problem that confusion occurs in detecting the object to be sensed or errors occur in the measurement of the direction or distance of the object to be sensed.

According to an aspect of the present invention, there is provided a method for detecting and measuring an object in a complex situation using a radar, including the steps of: A clutter map generating step of receiving a reflected wave signal for generating a clutter map including a clutter signal based on the received signal; A clutter region confirmation step of confirming a clutter region according to the position and size of the object causing the shadow effect based on the clutter map; A fluctuation information extracting step of extracting stochastic fluctuation information of a clutter signal through statistical analysis on the clutter map in the clutter area; A clutter information generation step of generating clutter information including the clutter signal and the variation information in the clutter area; And a correction signal generation step of removing the clutter signal from the received signal based on the clutter map to extract a detection signal and generating a correction signal from which the shadow effect is removed from the detection signal based on the clutter information And the sensing and distance of the sensing object are measured based on the correction signal.

Preferably, the clutter region checking step comprises: template matching the clutter map with the transmission signal to identify an area signal according to the location and size of the object causing the shadow effect; The clutter area can be confirmed.

More preferably, the clutter region checking step may include: calculating a cross correlation value between the clutter map and the transmission signal; Checking the area signal by comparing the cross-correlation value with a preset reference value; And estimating a position and a size of the object causing the shadow effect based on the area signal.

And when the region signal is confirmed according to a result of performing the clutter region checking step, the fluctuation information extracting step may include a step of extracting the fluctuation information, ; And generating the variation information based on the standard deviation.

The clutter information generating step may generate clutter information on the object by matching the correlation information with the cross-correlation value corresponding to the clutter region.

Preferably, the generating of the correction signal includes: a sensing signal extracting step of extracting a sensing signal by removing the clutter signal from the received signal based on the clutter map; A detection signal generation step of generating a detection signal by template matching the detection signal with the transmission signal; And a correction signal generation step of generating a correction signal by removing the shadow effect from the detection signal by reflecting the clutter information on the detection signal.

More preferably, the detection signal generation step may generate the detection signal by calculating a cross correlation value between the detection signal and the transmission signal.

And generating the correction signal includes: calculating a weight based on the variation information of the clutter information; Calculating an error signal according to the shadow effect by reflecting the weight to the cross-correlation value of the clutter information; And generating a correction signal in which the detection signal is corrected by subtracting the error signal from the detection signal.

The second embodiment of the object detection and distance measuring method using a radar according to the present invention is a method for detecting and measuring an object using a radar, A clutter map generating step of generating a clutter map including a clutter signal based on the received signal; A subject measurement step of extracting a detection signal by removing the clutter signal from the received signal based on the clutter map, and calculating a distance for each of a plurality of sensed objects by sensing a target object based on the sensing signal; An object comparison step of setting a sequence number for a plurality of objects according to a distance size and calculating a comparison value according to a time variation of a difference value of a distance difference between two objects in adjacent two sequences; And a multipath eliminating step of judging multipath based on the comparison value and removing any one of the objects of the two sequences from the detected plurality of objects.

Preferably, the object comparing step may include setting an order for a plurality of objects according to the distance size; Extracting objects of two adjacent sequences; A first difference value calculation step of calculating a first difference value for a distance difference at a first time between the extracted objects; A second difference value calculation step of calculating a second difference value between the extracted objects and the distance difference at the second time; And a comparison value calculation step of calculating a comparison value between the first difference value and the second difference value, wherein the multipath elimination step can determine the multipath by comparing the comparison value with a preset reference value .

More preferably, the object comparing step includes a first comparing step of comparing the first difference value with a first reference value to determine whether to multiply the first difference value; And a second comparing step of comparing the second difference value with a second reference value to determine whether the multi-path is multipath, the second difference value calculating step being performed according to a result of the first comparing step, The comparing value calculating step may be performed according to a result of the second comparing step.

Further, the object measuring step may include a sensing signal extracting step of extracting a sensing signal by removing the clutter signal from the received signal based on the clutter map; A detection signal generation step of generating a detection signal by template matching the detection signal with the transmission signal; Determining a presence or absence of an object by comparing the detection signal with a preset reference value; And a distance calculating step of sensing a target object based on the detection signal and calculating a distance of each of the plurality of detected target objects.

Here, the detection signal generation step may generate the detection signal by calculating a cross correlation value between the detection signal and the transmission signal.

The third embodiment of the object detection and distance measurement method in a complex situation using a radar according to the present invention is a method of detecting an object and measuring a distance using a radar according to the present invention is characterized in that it transmits a transmission signal of a radar, A clutter map generating step of generating a clutter map including a clutter signal based on the received signal; A clutter region confirmation step of confirming a clutter region according to the position and size of the object causing the shadow effect based on the clutter map; A fluctuation information extracting step of extracting stochastic fluctuation information of a clutter signal through statistical analysis on the clutter map in the clutter area; A clutter information generation step of generating clutter information including the clutter signal and the variation information in the clutter area; A correction signal generation step of removing the clutter signal from the received signal based on the clutter map to extract a detection signal and generating a correction signal from which the shadow effect is removed from the detection signal based on the clutter information; A subject measurement step of sensing a target object based on the correction signal and calculating a distance between the plurality of target objects sensed; An object comparison step of setting a sequence number for a plurality of objects according to a distance size and calculating a comparison value according to a time variation of a difference value of a distance difference between two objects in adjacent two sequences; And a multipath eliminating step of judging multipath based on the comparison value and removing any one of the objects of the two sequences from the detected plurality of objects.

According to the present invention, when detecting objects through the radar and measuring distances, a shadow effect that is mistaken for detecting the movement of fixed objects around the object to be sensed, or a shadow effect that is reflected on another object, The phenomenon can be removed to more accurately detect the object and measure the distance.

1 shows a schematic diagram of a UWB (ultra-wide band) UWB radar,
2 shows a schematic flow chart of a method for detecting and measuring an object of a radar according to the prior art,
FIG. 3 shows a conceptual diagram of a shadow effect generated when an object is detected and a distance is measured using a radar,
FIG. 4 is a conceptual diagram of a multipath phenomenon occurring when an object is detected and a distance is measured using a radar,
5 is a schematic block diagram of an embodiment of a radar system for implementing object detection and distance measurement in a complex situation using a radar according to the present invention,
6 shows a flowchart of a first embodiment of an object detection and distance measuring method in a complex situation using a radar according to the present invention,
7 is a conceptual diagram of a clutter map generating process in the first embodiment of the object detecting and distance measuring method in a complex situation using a radar according to the present invention,
FIG. 8 is a flowchart illustrating an example of a clutter region checking process and a variation information extracting process in the first embodiment of the object detecting and distance measuring method in a complex situation using the radar according to the present invention,
FIG. 9 shows an example of generating clutter information according to the clutter region checking process and the variation information extracting process in the first embodiment of the object detecting and distance measuring method in a complex situation using the radar according to the present invention,
10 is a flowchart illustrating an example of a correction signal generation process in which a shadow effect is removed in the first embodiment of the object detection and distance measurement method in a complex situation using a radar according to the present invention,
11 shows a flowchart of a second embodiment of object detection and distance measuring method in a complex situation using a radar according to the present invention,
12 is a flowchart illustrating an example of an object detection process in a second embodiment of the object detection and distance measurement method in a complex situation using a radar according to the present invention,
13 shows the characteristics of the multipath phenomenon,
14 is a flowchart illustrating an example of a multipath elimination process in the second embodiment of the object detection and distance measurement method in a complex situation using a radar according to the present invention,
FIG. 15 shows a flowchart of a third embodiment of an object detection and distance measuring method in a complex situation using a radar according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

First, the terminology used in the present application is used only to describe a specific embodiment, and is not intended to limit the present invention, and the singular expressions may include plural expressions unless the context clearly indicates otherwise. Also, in this application, the terms "comprise", "having", and the like are intended to specify that there are stated features, integers, steps, operations, elements, parts or combinations thereof, But do not preclude the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention eliminates multipath phenomenon in which a shadow effect that is mistakenly detected as a motion of fixed objects around a sensing object in detecting an object through a radar and a distance measurement or a signal reflected by a sensing object reflects to another object Discloses a method for detecting an object more accurately and measuring a distance.

An embodiment of a radar system for implementing object detection and distance measurement in a complex situation using a radar according to the present invention will be described with reference to FIG.

Since the configuration diagram of the embodiment of FIG. 5 is for explaining the configuration for implementing the features of the present invention, the detailed configuration of the radar system is shown in a simplified form. Generally, the configuration of the radar system and the detailed A description thereof will be omitted. In addition, the radar system embodying the present invention is not limited to the configuration shown in FIG. 5, but may selectively include various configurations that may be included in a known radar system.

The radar system to which the present invention shown in FIG. 5A is applied basically includes a transmitting unit 110, a receiving unit 120, a synchronizing unit 130, a signal processing unit 140, an output unit 150, can do.

The transmitting unit 110 roughly includes a pulse generator and a controller to generate and propagate a radar transmission signal. In this case, the transmission signal may include various frequency bands selected depending on the object detection purpose and the limiting condition of the radar And an ultra-wide band (UWB) may be applied as an example. The transmission signal generated by the transmission unit 110 is propagated through the transmission antenna 115.

The receiving unit 120 receives a reflected wave signal for a transmitting signal transmitted from the transmitting unit 110 through a receiving antenna 125 and extracts a necessary portion from the received signal including a sampler. At this time, the synchronization unit 130 supports synchronization with the transmission signal for sampling the sampler.

The signal processing unit 140 determines an object detection signal in the sampled signal and detects a target object, and generates information such as a position and a distance of the target object according to the object detection signal. The output unit 150 outputs information generated by the signal processing unit 140 Output.

In order to more accurately detect a target object, a plurality of transmission signals are propagated, a plurality of reception signals are received, a clutter map is generated based on the received signals, and a clutter signal is removed from a received signal through a clutter map Correct noise or error.

However, in this method, the error correction due to the shadow effect or the multipath phenomenon is not adequately corrected. Therefore, the present invention further configures the signal correction unit 200. The signal correction unit 200 includes a signal processing unit 140, And corrects the signal to eliminate the error in the processing of the received signal. 5 (b), the signal correction unit 200 may include a shadow effect remover 210 and a multipath developer remover 230, 210, and supports a function of correcting an error due to a multipath phenomenon through the multi-path developer remover 230. FIG.

Here, the signal correction unit 200 may be implemented as a specialized device having functions such as arithmetic operation and storage within the radar system 100 to correct an error of a radar signal, but preferably performs a sort of arithmetic function The shadow effect removing unit 210 of the signal correcting unit 200 and the multipath developer remover 230 may be programs executed on a PC.

Hereinafter, an object sensing method and a distance measuring method in a complex situation using a radar according to the present invention implemented through the radar system shown in FIG. 5 will be described with reference to embodiments. And a second feature for eliminating the multipath phenomenon will be described. Embodiments of the present invention will be described with respect to each feature. In the present invention, a third feature that combines a first feature for eliminating the shadow effect and a second feature for eliminating the multipath phenomenon is presented, and a description will be given of the third feature.

In the following embodiments, signals may denote the signals themselves, but they may also mean the magnitudes of the signals depending on the circumstances, which need to be properly interpreted as needed.

A first feature of the present invention is to remove a shadow effect in an object detection and distance measurement method in a complex situation using a radar according to the present invention. The outline of the first feature of the present invention is that a radar transmission signal is propagated Generating a clutter map including a clutter signal based on the received signal; receiving a reflected wave signal from the clutter map; A clutter region confirmation step of confirming a clutter region according to the position and size of the object causing the shadow effect based on the clutter map; A fluctuation information extracting step of extracting stochastic fluctuation information of a clutter signal through statistical analysis on the clutter map in the clutter area; A clutter information generation step of generating clutter information including the clutter signal and the variation information in the clutter area; And a correction signal generation step of removing the clutter signal from the received signal based on the clutter map to extract a detection signal and generating a correction signal from which the shadow effect is removed from the detection signal based on the clutter information And a result of removing the shadow effect can be obtained by measuring the sensing object and the distance based on the correction signal.

In this regard, FIG. 6 shows a flowchart of a first embodiment of an object detection and distance measuring method in a complex situation using a radar according to the present invention.

The radar transmission signal is transmitted (S110) through the radar system shown in FIG. 5 and the reflected wave signal of the propagated signal is received (S130). The process of receiving the transmission signal propagation and the reception signal therefrom is repeated a plurality Respectively.

Clutter is an undesired reflection wave of a radar. It is a kind of noise that is reflected on a radar screen, such as ground, sea, rain, obstacle, jamming, and so on.

In order to remove the clutter, a clutter map for a plurality of received signals is generated (S150).

FIG. 7 shows an example of a process of generating a clutter map. Referring to FIG. 7, the clutter map includes a stationary component by a fixed object and a motion component by a moving object ), And the received signals of I 1 to I 5 storing a plurality of received signals are added up and averaged, and as shown in the I av signal of FIG. 7, the elements of the fixed object are the same However, as the number of received signals increases, the element due to the moving object gradually disappears and only the element due to the fixed object remains.

That is, the clutter map is information obtained by summing the received signals a plurality of times and extracting the average signal, thereby enabling to extract the clutter signal generated by the fixed object, which is the main factor of the clutter of the radar.

Referring back to FIG. 6, the first embodiment of the present invention will be described. When the clutter map is generated, the clutter region is confirmed based on the clutter map (S210) The method comprising the steps of: determining whether a target object exists in which position and size; identifying the region signal according to the position and size of the object causing the shadow effect by template matching the clutter map with the transmission signal; , And confirms the clutter area based on the area signal.

When the clutter region is confirmed, a statistical analysis is performed on the clutter map (S230), and the variation of the signal is statistically determined by the object causing the clutter, and the variation information about the clutter is generated based thereon.

The clutter information is generated by matching the clutter region with the fluctuation information (S250).

8, in the first embodiment of the object detecting and distance measuring method in a complex situation using the radar according to the present invention, the clutter region checking process (S210) and the clutter statistical analyzing process (S230) FIG. 8 is a flowchart illustrating an example of a confirmation process and a variation information extracting process. Referring to FIG. 8, a detailed description will be given of a clitoral region checking process (S210) and a clutter statistical analysis process (S230).

The clutter map CM is generated as an average of the plurality of received signals (S155), and then the clutter map CM is template-matched to the transmission signal TS (S210) Template matching computes the similarity by multiplying the transmitted signal's value by moving the clutter map for the received signal from the beginning to the end of the signal. , The largest value appears at the portion where the clutter map CM and the transmission signal TS are most similar to each other.

At this time, as a template matching, a cross-correlation value cross-correlated with the clutter map CM and the transmission signal TS is calculated (S211). The cross correlation is a method of comparing the similarity between the signals, Can be calculated by applying Equation (1).

[Formula 1]

Figure 112015063148372-pat00001

Where P v is the cross-correlation value, CW is the clutter map, TS is the transmit signal, and N is the total number of transmit signals.

And by the cross-correlation value P v for the predetermined reference value Th d and compared (S215) to determine the area signal for the clutter present. In this case, the reference value can be appropriately selected as needed, and if it is desired to find the existence of the clutter in detail, the value can be lowered and the value can be increased if it is desired to find the existence of the more accurate clutter. That is, it can be estimated that there is a clutter in a region where the cross-correlation value P v of the transmission signal TS to the clutter map CM is larger than a preset reference value.

Next, a statistical analysis is performed between the received signal RD and the clutter map CM with respect to the portion where the clutter region is confirmed. In order to grasp the degree of fluctuation of the difference between the plurality of received signals and the clutter map, And calculates the standard deviation C dev for the difference between the clutter map CM and the clutter map CM (S235).

Through the above-described process, the cross-correlation value P v of the portion identified as the clutter region and the C dev , which is the variation information of the clutter, are included in the clutter region confirmation process (S210) (S255).

As an example of this, in the first embodiment of the object detecting and distance measuring method in a complex situation using the radar according to the present invention shown in FIG. 9, the clutter information checking process and the clutter information When a reference, determine the clutter region to the fixed target chain shelves J1 to cause clutter and the cross-correlation value for that P v (J1) and variation information, the standard deviation of C dev (J1) a clutter information CO (J1 ).

Referring back to FIG. 6, the following steps will be further described. The clutter signal is removed from the received signal based on the clutter map, and the detection signal is extracted. Based on the clutter information generated through the above- The process of removing the shadow effect from the signal (S270) is performed to generate a correction signal from which the shadow effect is removed (S290).

In other words, even when the clutter signal is removed from the received signal to the clutter map, the signal according to the shadow effect still exists. In the present invention, the clutter region confirmation process is performed on the detection signal from which the clutter signal is removed from the received signal to the clutter map The correction signal is extracted by removing the error signal according to the shadow effect by reflecting the magnitude of the clutter signal calculated in step S210 and the degree of fluctuation of the clutter signal calculated through the statistical analysis process of the clutter S230 .

The process of removing the shadow effect (S270) and the process of generating the correction signal (S290) through the process (S270) are similar to those of the first embodiment of the object detection and distance measuring method in a complex situation using the radar according to the present invention A more detailed description will be given with reference to a flowchart of an example of a correction signal generation process in which a shadow effect is removed.

First, the clutter map CM is subtracted from the stored received signal RD to extract the clutter-removed detection signal CW (S271).

Then, the detection signal P is generated by template matching the transmission signal TS with the sensing signal CW (S272). As has been described in the template matching, the transmission signal TS is cross-correlated with the sensing signal CW, It is possible to generate the detection signal P according to the degree.

If the value of the currently calculated detection signal is greater than the value of the detection signal calculated in the previous transmission signal (S273), the shadow effect is removed from the detection signal. In this case, If the value of the currently calculated detection signal is smaller than the value of the detection signal calculated in the previous transmission signal, it is determined that the object itself does not exist. This is because, in the case of the moving object to be measured, the size of the moving object changes from the previous transmission signal and the current transmission signal, the moving object to be measured can be discriminated by considering the degree of change.

In detail, the error signal P err is calculated by reflecting the fluctuation information C dev included in the clutter information and the cross-correlation value P v in the clutter region, wherein the error signal P err can be calculated by the following equation (2).

[Formula 2]

Figure 112015063148372-pat00002

Where P err is the error signal value, α is the weight, k is the predetermined constant, C dev is the variation information included in the clutter information, and P v is the cross-correlation value included in the clutter information. In this case, k is a constant that is set as needed, and can be selected according to the setting of the accuracy of the error signal. If C dev is 0, the weight α is set to zero.

Looking at the meaning of the error signal P err, location and size of the stationary target object to cause the clutter, as previously discussed in the clutter area check process (S210) may be considered as a cross-correlation value P v, also Clutter As shown in the statistical analysis process (S230), the degree of fluctuation of the clutter can be considered as the standard deviation C dev , so that the degree of the error signal P err due to the fixed object inducing the clutter can be grasped.

Then, the corrected detection signal P sh is extracted by subtracting the error signal P err from the detection signal P (S274), and the corrected detection signal P sh is set as the correction signal from which the error corresponding to the shadow effect is removed.

If this same process, a correction signal is generated by P sh, sh P to the correction signal to a predetermined threshold value Th and d compared (S275), and determines the target object will be counted (S276) an object DO based on the result. At this time, the preset reference value Th d for comparing the correction signal P sh can be set as needed. For example, when the accuracy of the object detection is increased, the numerical value is set lower and when the accuracy of object detection is increased, You can set the value higher.

Further, the above process is repeatedly performed (S277, S278) by the total number W of the plurality of received signals, and the detection result for the object is generated by combining the results (S295).

Through the above process, the present invention removes the shadow effect by a simple process, thereby further improving the accuracy of the radar, thereby enabling accurate detection and distance measurement of the moving object.

A second aspect of the present invention is a method for eliminating a multipath phenomenon in an object detection and distance measuring method using a radar according to the present invention. A clutter map generating step of generating a clutter map including a clutter signal based on the received signal by receiving the reflected wave signal; A subject measurement step of extracting a detection signal by removing the clutter signal from the received signal based on the clutter map, and calculating a distance for each of a plurality of sensed objects by sensing a target object based on the sensing signal; An object comparison step of setting a sequence number for a plurality of objects according to a distance size and calculating a comparison value according to a time variation of a difference value of a distance difference between two objects in adjacent two sequences; And a multipath eliminating step of judging multipath based on the comparison value and removing one of the objects of the two sequences from the detected plurality of objects.

In this regard, FIG. 11 shows a flowchart of a second embodiment of object detection and distance measurement method in a complex situation using a radar according to the present invention.

5, a radar transmission signal is transmitted (S510) and a reflected wave signal of the propagated signal is received (S530). A process of receiving a transmission signal propagation and a reception signal therefrom is repeated a plurality Respectively.

Then, the clutter map is generated and the clutter is removed from the received signal through the clutter map (S550). Since the process has been described in detail in the first embodiment, a description thereof will be omitted.

When the detection signal from which the clutter is removed from the received signal is extracted, a process of detecting an object by performing template matching of the detection signal and the transmission signal (S570) is performed.

Referring to a flow chart of an object detecting process in the second embodiment of the object detecting and distance measuring method in a complex situation using the radar according to the present invention shown in FIG. 12 in connection with the object detecting process (S570) Let's look at it.

First, the clutter map CM is subtracted from the stored received signal RD to extract the clutter-removed detection signal CW (S555).

The detection signal P is generated by template matching the transmission signal TS with the sensing signal CW (S5712). As has been described in the template matching, the transmission signal TS is cross-correlated with the sensing signal CW, Can be generated.

If the current detection signal value is greater than the detection signal value calculated in the previous transmission signal (S572), the object detection is performed. In the case of the moving object to be measured, the previous transmission signal and the current transmission signal It is possible to determine the moving object to be measured in consideration of the degree of change.

Next, the detection signal P is compared with the preset reference value Th d to determine whether or not the object exists (S573), and the object DO is counted according to the result (S574).

Further, the above process is repeatedly performed by the total number W of the plurality of received signals (S575, S576), and the detection result for the target object is generated by combining the results (S580).

Through such a process, a result of sensing each object is generated (S580).

11, the distance to the target object is calculated (S590). The distance to the target object is calculated from the distance from the transmission signal to the reception signal in consideration of the time lapse from the transmission signal to the reception signal, Can be calculated.

Then, in step S650, the multi-path elimination process is performed in step S650. In step S650, the corrected multi-path is calculated based on the calculated distance value.

Hereinafter, a process of removing a multipath will be described in more detail with reference to an example. First, the characteristics of a multipath will be described with reference to FIG.

13 shows a case where a wall exists as a fixed object 30 in the periphery of the moving object 10 and a multipath phenomenon occurs. When the moving object 10 is moved from the position shown in FIG. 13 (a) In the case of moving to the position shown in FIG. 13 (b), a phenomenon that the signal due to the multipath is moved as the main signal by the moving object 10 appears as shown in FIG. That is, when the main signal advances according to the movement of the moving object 10, the signal due to the multipath advances as well. When the main signal is backward, the signal due to the multipath also reverses. At this time, The gap has the property to remain constant.

In the present invention, a method of eliminating a signal by multipath using the characteristics of a multipath signal is disclosed. In the present invention, distance variation between two objects located within a certain distance of a sensed object is compared, And estimates it as a multi-path.

FIG. 14 is a flow chart illustrating an example of a multi-path removal process according to the second embodiment of the object detection and distance measurement method in a complex situation using a radar according to the present invention (S610) do.

First, the distance to each of the sensed objects is calculated (S595), and the sequence number is set according to the distance size of the sensed objects. And adjacent to the first difference value DD t1 of the two sequence numbers I and I + extracts the target object 1 to I distance times the target object in time t1 D t1 (I) and a distance of one I + 1 object D t1 (I + 1) (S611).

The first difference value DD t1 is compared with the first reference value D th1 (S612), and if it exceeds the first difference value DD t1 , it is regarded as not multipath. If the first difference value DD t1 is smaller than the first reference value D th1, the second difference between the distance D t2 (I) of the object I at the time t2 and the distance D t2 (I + 1) of the object I + The value DD t2 is calculated (S613) and compared with the second reference value D th2 (S614).

When the second difference value DD t2 is smaller than the second reference value D th2 , a comparison value DS between the first difference value DD t1 and the second difference value DD t2 is calculated (S615), and the comparison value DS is compared with the predetermined reference value DS th (S616), and determines whether or not the multipath exists.

If it is determined that there is a multipath, either one of the signal of the object I and the signal of the object I + 1 is estimated to be generated by multipath, and one of the two objects is eliminated (S617).

14, the process of comparing the first difference value DD t1 with the first reference value D th1 and comparing the second difference value DD t2 with the second reference value D th2 is omitted, and the first difference value DD t1 and It is also possible to determine whether the multipath exists by calculating the comparison value DS for the second difference value DD t2 and determining the comparison value DS.

This process is repeatedly applied to all the detected objects (S618 and S619), and the detected object is corrected (S655) by integrating the results.

In addition, in the present invention, a method for sensing objects and measuring distances in a complex situation using a radar, which combines the first characteristic for eliminating the shadow effect and the second characteristic for eliminating the multipath phenomenon, A flow chart of a third embodiment of object detection and distance measurement method in a complex situation using a radar according to the invention is shown.

The third embodiment shown in FIG. 15 is an embodiment for simultaneously removing the shadow effect and the multipath phenomenon by combining the first embodiment shown in FIG. 6 and the second embodiment shown in FIG. 11 The description of the first embodiment shown in FIG. 6 and the second embodiment shown in FIG. 11 will be briefly described.

When a reflected wave signal of a propagated signal is received (S530) by propagating a radar transmission signal (S510), a plurality of received signals are stored and a clutter map is generated based on the received signals (S730).

Then, the shadow effect removal process (S740) is performed as described above with reference to the first embodiment.

In the third embodiment, as described in the first embodiment of FIG. 6, the process of removing the shadow effect is performed by checking the clutter region and analyzing the variation information And generates clutter information including the clutter region and the variation information, and removes the shadow effect using the clutter information.

Through the above process, a correction signal from which the shadow effect is removed is generated (S750), the object is detected through the correction signal, and the distance is calculated (S760). Then, the multipath elimination process (S770) is performed according to the second embodiment.

In the process of removing the multipaths (S770), as described in the second embodiment of FIG. 11, it is determined whether a multipath exists based on a comparison value obtained by comparing the variation of the detected objects, And eliminates multipath by removing one of two adjacent objects.

After obtaining the correction signal through the process of removing the shadow effect, the distance is calculated by sensing the object with the obtained correction signal, and multipath is removed by the comparison value according to the distance variation of the objects. Finally, It is possible to obtain a corrected result of removing the multipath and removing the error (S780).

As described above, according to the present invention, a shadow effect, which is mistakenly detected as a motion of fixed objects around a sensing object, or a signal reflected from the sensing object, By eliminating the multipath phenomenon, it is possible to detect the object more accurately and measure the distance.

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. Therefore, the embodiments of the present invention are not intended to limit the scope of the present invention but to limit the scope 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 thereof should be construed as being included in the scope of the present invention.

10: Moving object,
30: fixed object,
100: radar system,
110: transmitting unit, 115: transmitting antenna,
120: receiving section, 125: receiving antenna,
130: synchronization unit,
140: a signal processor,
150: output section,
200: signal correction unit,
210: Shadow effect removal,
230: Multi-path developer rejection.

Claims (14)

A method for detecting and measuring an object using a radar,
A clutter map generation step of propagating a transmission signal of the radar, receiving a reflected wave signal therefrom, and generating a clutter map including a clutter signal based on the received signal;
A clutter region confirmation step of confirming a clutter region according to the position and size of the object causing the shadow effect based on the clutter map;
A fluctuation information extracting step of extracting stochastic fluctuation information of a clutter signal through statistical analysis on the clutter map in the clutter area;
A clutter information generation step of generating clutter information including the clutter signal and the variation information in the clutter area; And
A correction signal generation step of removing the clutter signal from the received signal based on the clutter map to extract a detection signal and generating a correction signal from which the shadow effect is removed from the detection signal based on the clutter information In addition,
And detecting the sensing object and the distance based on the correction signal. The method of sensing an object and measuring distance in a complex situation using a radar. The method according to claim 1,
The clutter region checking step includes:
The clutter map is template-matched to the transmission signal to identify an area signal according to the location and size of the object causing the shadow effect, and confirms the clutter area based on the area signal. Object detection and distance measurement in complex situations using radar. 3. The method of claim 2,
The clutter region checking step includes:
Calculating a cross correlation value between the clutter map and the transmission signal;
Checking the area signal by comparing the cross-correlation value with a preset reference value; And
And estimating a position and a size of a target object causing a shadow effect on the basis of the area signal. A method for detecting and measuring an object in a complex situation using a radar. 3. The method of claim 2,
If the region signal is confirmed according to a result of the clutter region checking step, performing the fluctuation information extracting step,
In the variation information extracting step,
Calculating a standard deviation of a difference value between the received signal and the clutter map; And
And generating the variation information on the basis of the standard deviation. 5. The method of claim 4,
The clutter information generation step includes:
And the clutter information for the object is generated by matching the mutual correlation value corresponding to the clutter region with the variation information, and detecting the object in the complex situation using the radar. 6. The method of claim 5,
Wherein the correction signal generation step comprises:
A sensing signal extracting step of extracting a sensing signal by removing the clutter signal from the received signal based on the clutter map;
A detection signal generation step of generating a detection signal by template matching the detection signal with the transmission signal; And
And generating a correction signal by removing the shadow effect from the detection signal by reflecting the clutter information on the detection signal. The method of detecting an object and the distance in a complex situation using a radar. The method according to claim 6,
The detection signal generation step includes:
And a cross correlation value between the sensing signal and the transmission signal is calculated to generate the detection signal, and the object sensing and distance sensing method in a complex situation using the radar. The method according to claim 6,
Wherein the correction signal generation step comprises:
Calculating a weight based on the fluctuation information of the clutter information;
Calculating an error signal according to the shadow effect by reflecting the weight to the cross-correlation value of the clutter information; And
And generating a correction signal by subtracting the error signal from the detection signal and correcting the detection signal. A method for detecting and measuring an object using a radar,
A clutter map generation step of propagating a transmission signal of the radar, receiving a reflected wave signal therefrom, and generating a clutter map including a clutter signal based on the received signal;
A subject measurement step of extracting a detection signal by removing the clutter signal from the received signal based on the clutter map, and calculating a distance for each of a plurality of sensed objects by sensing a target object based on the sensing signal;
An object comparison step of setting a sequence number for a plurality of objects according to a distance size and calculating a comparison value according to a time variation of a difference value of a distance difference between two objects in adjacent two sequences; And
And a multipath eliminating step of multipath detection based on the comparison value and removing any one of the objects of the two sequences from the detected plurality of objects. Distance measurement method. 10. The method of claim 9,
The object comparison step may include:
Setting an order for a plurality of objects according to a distance size;
Extracting objects of two adjacent sequences;
A first difference value calculation step of calculating a first difference value for a distance difference at a first time between the extracted objects;
A second difference value calculation step of calculating a second difference value between the extracted objects and the distance difference at the second time; And
And a comparison value calculating step of calculating a comparison value between the first difference value and the second difference value,
Wherein the multipath elimination step comprises:
And comparing the comparison value with a preset reference value to determine multipath. The method of detecting and measuring an object in a complex situation using a radar. 11. The method of claim 10,
The object comparison step may include:
A first comparing step of comparing the first difference value with a first reference value to determine whether to multiply the first difference value; And
Further comprising a second comparing step of comparing the second difference value with a second reference value to determine whether to multiply the difference value,
Wherein the second difference value calculation step comprises:
Wherein the second contrast step is performed according to the result of the first contrast step,
The comparison value calculating step may include:
And the second contrast step is performed according to the result of the second contrast step. 12. The method of claim 11,
Wherein the object measurement step comprises:
A sensing signal extracting step of extracting a sensing signal by removing the clutter signal from the received signal based on the clutter map;
A detection signal generation step of generating a detection signal by template matching the detection signal with the transmission signal;
Determining a presence or absence of an object by comparing the detection signal with a preset reference value; And
And a distance calculating step of sensing a target object based on the detection signal and calculating a distance of each of the plurality of detected target objects. 13. The method of claim 12,
The detection signal generation step includes:
And a cross correlation value between the sensing signal and the transmission signal is calculated to generate the detection signal, and the object sensing and distance sensing method in a complex situation using the radar. A method for detecting and measuring an object using a radar,
A clutter map generation step of propagating a transmission signal of the radar, receiving a reflected wave signal therefrom, and generating a clutter map including a clutter signal based on the received signal;
A clutter region confirmation step of confirming a clutter region according to the position and size of the object causing the shadow effect based on the clutter map;
A fluctuation information extracting step of extracting stochastic fluctuation information of a clutter signal through statistical analysis on the clutter map in the clutter area;
A clutter information generation step of generating clutter information including the clutter signal and the variation information in the clutter area;
A correction signal generation step of removing the clutter signal from the received signal based on the clutter map to extract a detection signal and generating a correction signal from which the shadow effect is removed from the detection signal based on the clutter information;
A subject measurement step of sensing a target object based on the correction signal and calculating a distance between the plurality of target objects sensed;
An object comparison step of setting a sequence number for a plurality of objects according to a distance size and calculating a comparison value according to a time variation of a difference value of a distance difference between two objects in adjacent two sequences; And
And a multipath eliminating step of multipath detection based on the comparison value and removing any one of the objects of the two sequences from the detected plurality of objects. Distance measurement method.
KR1020150092619A 2015-06-30 2015-06-30 Method of detecting object and measuring distance with rader in complicated circumstances KR101792114B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020150092619A KR101792114B1 (en) 2015-06-30 2015-06-30 Method of detecting object and measuring distance with rader in complicated circumstances

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150092619A KR101792114B1 (en) 2015-06-30 2015-06-30 Method of detecting object and measuring distance with rader in complicated circumstances

Publications (2)

Publication Number Publication Date
KR20170002816A KR20170002816A (en) 2017-01-09
KR101792114B1 true KR101792114B1 (en) 2017-11-02

Family

ID=57810752

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020150092619A KR101792114B1 (en) 2015-06-30 2015-06-30 Method of detecting object and measuring distance with rader in complicated circumstances

Country Status (1)

Country Link
KR (1) KR101792114B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20200131526A (en) * 2019-05-14 2020-11-24 주식회사 마크에이트 Position Detecting System and Method of Ultra Wide Band Using the Optimized Detection Threshold at Objects Size and Motion Strenth
WO2022220969A1 (en) * 2021-04-13 2022-10-20 Aurora Operations, Inc. Multipath correction for reflections

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102666977B1 (en) 2017-01-09 2024-05-20 삼성전자주식회사 Electronic device and method for photographing image thereof
KR101885922B1 (en) * 2018-01-17 2018-08-06 엘아이지넥스원 주식회사 Apparatus and system for generating model of clutter using radar video signal and method thereof
KR102105161B1 (en) * 2018-09-27 2020-04-28 알에프코어 주식회사 Hybrid radar sensor and method of operating the same
KR20200101142A (en) 2019-02-19 2020-08-27 삼성전자주식회사 Electronic apparatus and method for controlling image in electronic apparatus
KR102136245B1 (en) * 2020-01-13 2020-07-21 국방과학연구소 Apparatus, method, computer-readable storage medium and computer program for detecting and selecting target
KR102333582B1 (en) * 2021-03-03 2021-12-01 (주)노바코스 Ghost removal apparatus and method of smart radar vehicle detection system for road traffic
KR102333486B1 (en) * 2021-03-03 2021-12-01 (주)노바코스 Ghost treatment apparatus and method of smart radar vehicle detection system for road traffic

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008164494A (en) 2006-12-28 2008-07-17 Mitsubishi Electric Corp Guidance device
JP2011095120A (en) 2009-10-30 2011-05-12 Tokyo Keiki Inc Target tracking device and target tracking method
JP2011257204A (en) 2010-06-08 2011-12-22 Kitakyushu Foundation For The Advancement Of Industry Science & Technology Clutter suppression device and radar device
JP2015021966A (en) 2013-07-22 2015-02-02 三菱電機株式会社 Method and system for detecting target in scene behind wall

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008164494A (en) 2006-12-28 2008-07-17 Mitsubishi Electric Corp Guidance device
JP2011095120A (en) 2009-10-30 2011-05-12 Tokyo Keiki Inc Target tracking device and target tracking method
JP2011257204A (en) 2010-06-08 2011-12-22 Kitakyushu Foundation For The Advancement Of Industry Science & Technology Clutter suppression device and radar device
JP2015021966A (en) 2013-07-22 2015-02-02 三菱電機株式会社 Method and system for detecting target in scene behind wall

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20200131526A (en) * 2019-05-14 2020-11-24 주식회사 마크에이트 Position Detecting System and Method of Ultra Wide Band Using the Optimized Detection Threshold at Objects Size and Motion Strenth
KR102322480B1 (en) 2019-05-14 2021-11-05 주식회사 마크에이트 Position Detecting System and Method of Ultra Wide Band Using the Optimized Detection Threshold at Objects Size and Motion Strenth
WO2022220969A1 (en) * 2021-04-13 2022-10-20 Aurora Operations, Inc. Multipath correction for reflections

Also Published As

Publication number Publication date
KR20170002816A (en) 2017-01-09

Similar Documents

Publication Publication Date Title
KR101792114B1 (en) Method of detecting object and measuring distance with rader in complicated circumstances
JP6188640B2 (en) A system to detect targets in scenes behind walls
KR100791179B1 (en) Location calculating method and location estimating apparatus
EP2284569B1 (en) Automatic focussing of SAR raw data based on the estimation of the phase error function
JP6415288B2 (en) Radar equipment
KR20090125283A (en) System and method for positioning
CN102193089B (en) Method and device for processing echo signal, radar device and echo signal processing program
CN110988834B (en) Pulse arrival time measuring method based on self-adaptive threshold value double thresholds
US11061102B2 (en) Position estimating apparatus, position estimating method, and terminal apparatus
KR101897763B1 (en) Method and apparatus for distance measurement using radar
CN114285500A (en) UWB indoor positioning channel quality assessment method
JP5752481B2 (en) Passive radar device, guidance device, and radio wave detection method
US7916814B2 (en) Method and apparatus for real-time pulse parameter estimator
CN107271973A (en) CFAR detection method based on degree of skewness and average ratio under Weibull clutter environment
EP3249424B1 (en) Distance measuring method and device
KR102011959B1 (en) Method and Apparatus for Processing Radar Received Signal for Detecting Interference Signals in Pulse Compression Process
RU2550576C1 (en) Method to measure distance to noisy object
KR20170061019A (en) Method of detecting parking lot with rader
US20100081426A1 (en) Method for Classifying Radio Channels
KR20130034095A (en) Apparatus and method estimating doa/toa of mobile signal
JP7006587B2 (en) Feature measurement device, radio environment calculation device, feature measurement method, radio environment measurement method, program
RU2559310C2 (en) Method of estimating distance to noisy object at sea
US10480932B2 (en) Automated computation of a dimension of a moving platform
RU2646857C1 (en) Method of moving target selection
JP5911315B2 (en) Signal processing apparatus, PRI estimation apparatus, and PRI estimation method

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant