KR101626867B1 - Radio altimeter using adaptive threshold value and operating method thereof - Google Patents

Radio altimeter using adaptive threshold value and operating method thereof Download PDF

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KR101626867B1
KR101626867B1 KR1020150142388A KR20150142388A KR101626867B1 KR 101626867 B1 KR101626867 B1 KR 101626867B1 KR 1020150142388 A KR1020150142388 A KR 1020150142388A KR 20150142388 A KR20150142388 A KR 20150142388A KR 101626867 B1 KR101626867 B1 KR 101626867B1
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threshold value
received signal
adaptive threshold
signal
value
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KR1020150142388A
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Korean (ko)
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전재우
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엘아이지넥스원 주식회사
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    • 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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/882—Radar or analogous systems specially adapted for specific applications for altimeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C5/00—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels
    • G01C5/005—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels altimeters for aircraft

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

Abstract

Disclosed are a radio altimeter using an adaptive threshold value and an operating method. The radio altimeter comprises: a transmitting / receiving unit which transmits a radio frequency (RF) signal through an antenna installed on one side of a flight, and collects a receiving signal reflected from the surface or a structure in response to the RF signal; a signal processing unit which converts the collected receiving signal into an intermediate frequency (IF) bandwidth; and a controlling unit which generates the adaptive threshold value by using the converted receiving signal, and detects the receiving signal reflected from the surface among the receiving signal received through the antenna by using a basic threshold value, which is previously generated depending on an altitude measuring mode, or the adaptive threshold value.

Description

TECHNICAL FIELD [0001] The present invention relates to a radio altimeter using an adaptive threshold, and a radio altimeter using the adaptive threshold,

Field of the Invention [0002] The present invention relates to a radio altimeter, and more particularly, to a radio altimeter using an adaptive threshold considering an interference signal by a structure and a method of operating the radio altimeter.

In general, a radio altimeter is one of the altimeters used for finding the altitude (absolute altitude) from the ground surface in an airborne aircraft. The radio altimeter is a satellite altimeter that fires radio waves toward the ground and reflects from the ground surface. .

These radio altimeters include a frequency-modulated altimeter that emits frequency-modulated continuous waves and a pulse-type altimeter that emits pulses. The former is for low altitude, the latter for high altitude, and the frequency is 1,600 ~ 1,660MHz or 4,200 ~ 4,400MHz.

The radio altimeter transmits a signal toward the ground through a transmission antenna mounted on the back of the aircraft, and receives a signal reflected from the ground surface through the reception antenna and returns.

However, if a variety of structures are mounted on the back of an aircraft or if an aircraft is developed in a small size, physical and electrical interference with other equipment may occur when the antenna is mounted, which may cause malfunctions.

In addition, if the received signal is equal to or greater than a predetermined threshold value, it is determined to be an effective signal. However, there is a possibility that a false signal is detected when the interference signal to the structure around the antenna is equal to or more than the threshold value.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for collecting interference signals for a structure for each RF transmission output, generating an adaptive threshold using the collected interference signals, And a method of operating the radio altimeter using an adaptive threshold for detecting a reflected signal.

However, the objects of the present invention are not limited to those mentioned above, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above objects, a radio altimeter according to one aspect of the present invention transmits an RF (Radio Frequency) signal through an antenna mounted on one side of a flying body, and collects a reception signal reflected from the ground surface or the structure in response thereto A transmission / reception unit; A signal processor for converting the collected reception signal into an intermediate frequency (IF) band; And generating an adaptive threshold value using the converted received signal and detecting a reception signal reflected from the surface of the reception signal collected through the antenna using a preliminarily generated basic threshold value or the adaptive threshold value according to the altitude measurement mode And a control unit.

Preferably, the transceiving unit collects a reception signal for a structure mounted on the other side of the air vehicle according to the RF transmission output according to the threshold measurement mode.

Preferably, the control unit generates the adaptive threshold value using the received signal reflected from the structure, and generates a value obtained by adding a predetermined size to the magnitude of the received signal reflected from the structure over time to the adaptive threshold value .

Preferably, the control unit adds a predetermined size to the size of the received signal reflected from the structure over time, performs a smoothing process on the maximum value based on the added value, and generates a smoothing processed value with the adaptation threshold .

Preferably, the controller determines the use of the adaptive threshold by determining that there is an influence on the structure if the magnitude of the received signal is greater than the basic threshold when the RF transmission power is at its maximum, Determining that there is no influence on the structure if the value is smaller than the threshold, and determining use of the basic threshold value.

According to another aspect of the present invention, there is provided a method of operating a radio altimeter, comprising: transmitting an RF (Radio Frequency) signal through an antenna mounted on a side of a flying object and collecting a reception signal reflected from the ground surface or a structure in response thereto; ; Converting the collected reception signals into IF (Intermediate Frequency) bands; And generating an adaptive threshold value using the converted received signal and detecting a reception signal reflected from the surface of the reception signal collected through the antenna using a preliminarily generated basic threshold value or the adaptive threshold value according to the altitude measurement mode .

Preferably, the collecting step collects received signals for a structure mounted on the other side of the air vehicle according to the RF transmission output according to the threshold measurement mode.

Preferably, the detecting step generates the adaptive threshold value using the received signal reflected from the structure, and generates a value obtained by adding a predetermined size to the magnitude of the received signal reflected from the structure over time to the adaptive threshold value .

Preferably, the detecting includes adding a preset size to the size of the received signal reflected from the structure over time, performing a smoothing process on the maximum value based on the added value, and applying the smoothed value to the adaptation threshold .

Preferably, the detecting step determines that there is an influence on the structure when the magnitude of the received signal is greater than the basic threshold value, determines use of the adaptive threshold, and determines the size of the received signal, Determining that there is no influence on the structure if the threshold value is smaller than the basic threshold value, and determining use of the basic threshold value.

Accordingly, the present invention collects interference signals for a structure for each RF transmission output, generates an adaptive threshold using the collected interference signals, and detects reflected signals from the ground using the generated adaptive threshold, There is an effect that the threshold design for each platform can be made without changing.

Further, the present invention has the effect of minimizing the influence on the structure around the antenna.

Further, since the present invention minimizes the influence on the structure around the antenna, it is possible to efficiently locate the antenna to the air vehicle.

Further, since the present invention can detect a signal reflected from the ground using the adaptive threshold value, the possibility of false detection of the received signal can be reduced.

1 is a diagram showing a schematic configuration of a radio wave altimeter according to an embodiment of the present invention.
2 is a diagram illustrating a principle of collecting a structure interference signal according to an embodiment of the present invention.
3 is a diagram illustrating a process of collecting a structure interference signal according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a design process of an adaptive threshold according to an exemplary embodiment of the present invention. Referring to FIG.
5 is a diagram illustrating a process of designing an adaptive threshold according to another embodiment of the present invention.
6 is a diagram illustrating a method for operating a radio altimeter according to an embodiment of the present invention.

Hereinafter, an apparatus and method for detecting an interference signal for a radio altimeter according to an embodiment of the present invention will be described with reference to the accompanying drawings. The present invention will be described in detail with reference to the portions necessary for understanding the operation and operation according to the present invention.

In describing the constituent elements of the present invention, the same reference numerals may be given to constituent elements having the same name, and the same reference numerals may be given thereto even though they are different from each other. However, even in such a case, it does not mean that the corresponding component has different functions according to the embodiment, or does not mean that the different components have the same function. It should be judged based on the description of each component in the example.

In particular, according to the present invention, an adaptive threshold is generated by using an interference signal collected for a structure of each RF (Radio Frequency) transmission output, and a reflected signal from the ground is detected by using the generated low threshold. Suggest a plan.

1 is a diagram showing a schematic configuration of a radio wave altimeter according to an embodiment of the present invention.

1, the radio altimeter according to the present invention may include a transmission antenna 110, a reception antenna 120, a transmission / reception unit 130, a signal processing unit 140, and a control unit 150.

The transmission antenna 110 may be mounted on one side of the airplane, for example, and may transmit an RF (Radio Frequency) signal.

The reception antenna 120 may be mounted on one side of the airplane, for example, to the backside thereof to receive the RF signal.

The transceiver 130 may transmit an RF signal through a transmission antenna and collect a reception signal reflected from the ground surface or the structure in response to the RF signal through the reception antenna.

At this time, when the threshold measurement mode is operated, the transmission / reception unit 130 can receive only the received signals reflected from the surrounding structure mounted on the air vehicle, excluding the ground propagation path.

2 is a diagram illustrating a principle of collecting a structure interference signal according to an embodiment of the present invention.

As shown in FIG. 2, when the threshold measurement mode is operated, the ground wave propagation path is excluded by using a radio wave absorber to design an adaptive threshold value that is not a basic threshold value. That is, it is possible to receive only the received signal reflected from the surrounding structure.

Therefore, only the received signal reflected from the structure can be received in the threshold measurement mode.

The signal processing unit 140 can convert the collected reception signal into an IF (Intermediate Frequency) band.

The control unit 150 may measure the altitude from the surface of the ground using a part or all of the converted received signals or may generate an adaptive threshold considering the influence of the structure.

For example, when the altitude measurement mode is operated, the controller 150 may detect the reflected signal from the surface of the converted received signal and perform the altitude measurement using the detected signal.

As another example, when operating the threshold measurement mode, the controller 150 may generate an adaptive threshold using only the received signals reflected from the structure.

At this time, when the altitude measurement mode is operated, the controller 150 can detect the received signal reflected from the surface of the received signal received through the antenna using the previously generated basic threshold value or the adaptive threshold value.

First, the basic threshold value is used to determine an effective signal and is generated in various ways, for example, it may be generated using a radar equation or may be generated using a radar altimeter characteristic.

For example, the radar equation used to generate the basic threshold is shown in Equation (1) below.

[Equation 1]

Figure 112015098415254-pat00001

Here, Pr denotes the intensity of the received signal, Pt denotes the transmission power, Gt denotes the transmission antenna gain, Gr denotes the reception antenna gain,? Denotes the wavelength,? Denotes the RCS (Rader Cross Section) , R represents distance and altitude.

3 is a diagram illustrating a process of collecting a structure interference signal according to an embodiment of the present invention.

As shown in FIG. 3, when the threshold measurement mode is selected according to the user's menu or key operation, the radio altimeter according to the present invention can transmit the RF signal while excluding the ground wave propagation path using the radio wave absorber.

Next, the radio altimeter can receive the reflected RF signal reflected from the structure.

Next, the inspection apparatus can design or generate a basic threshold value using a radar equation after signal processing (e.g., FFT (Fast Fourier Transform), etc.) of the received RF signal.

Next, the radio altimeter can check whether the received signal is larger than the base threshold value generated. That is, if the check result is that the received signal is larger than the predetermined threshold value, it is determined that there is an influence on the structure, so that the position of the structure is identified, the position of the identified structure is stored, Can be stored.

On the other hand, if the received signal is smaller than the basic threshold value, the radio altimeter can determine that there is no image for the structure and store the result of the influence on the structure of the received signal.

Next, the radio altimeter can confirm that the transmission power is the maximum. That is, the radio altimeter can increase the size of the RF signal and transmit it if the transmission power is not the maximum as a result of the confirmation.

On the other hand, the radio altimeter can determine the use of the basic threshold or the adaptive threshold according to the comparison result of the received signal and the basic threshold value, when the transmission power is maximum.

That is, the radio altimeter determines that there is an influence on the structure if the received signal is larger than the basic threshold as a result of the determination, and decides to use the adaptive threshold in the subsequent altitude measurement mode. If the received signal is smaller than the basic threshold, And determines to use the basic threshold value in the subsequent altitude measurement mode.

FIG. 4 is a diagram illustrating a design process of an adaptive threshold according to an exemplary embodiment of the present invention. Referring to FIG.

As shown in FIG. 4, there is shown an example of designing an adaptive threshold for excluding the influence on a structure interference by using a received signal when the transmission power is maximum.

If the transmission power is the maximum, the signal reflected from the surface of the ground is excluded and only the received signal reflected from the surrounding structure is collected (400a), and the adaptive threshold can be generated using the collected received signal (400b).

At this time, the adaptive threshold value is generated by adding a predetermined magnitude, for example, 10 dB to the magnitude of the received signal over time, and smoothing the adaptive threshold value through the maximum value. The reason why the smoothing process is performed is to remove discontinuity and fine fluctuation.

Only the received signal reflected from the surface of the ground can be detected at the altitude measurement using the generated adaptive threshold (400c). That is, the adaptive threshold according to the present invention is designed to exclude the interference signal for the structure and to detect only the received signal reflected from the ground surface.

5 is a diagram illustrating a process of designing an adaptive threshold according to another embodiment of the present invention.

As shown in FIG. 5, there is shown an example of designing an adaptive threshold for excluding influence of structure interference by using a received signal when the transmission power is minimum.

If the transmission power is the minimum, the signal reflected from the surface of the ground is excluded and only the reception signal reflected from the surrounding structure is collected (500a), and the adaptive threshold can be generated using the collected reception signal (500b).

At this time, the adaptive threshold value is generated by adding a predetermined magnitude, for example, 10 dB to the magnitude of the received signal over time, and smoothing the adaptive threshold value through the maximum value. The reason why the smoothing process is performed is to remove discontinuity and fine fluctuation.

Only the received signal reflected from the surface of the ground can be detected at the time of altitude measurement using the generated adaptive threshold (500c). That is, the adaptive threshold according to the present invention is designed to exclude the interference signal for the structure and to detect only the received signal reflected from the ground surface.

6 is a view illustrating a checking method for a radio altimeter according to an embodiment of the present invention.

As shown in FIG. 6, the altitude measurement mode according to the present invention can be selected according to a user's menu or key operation (S601). The mode operated here includes an altitude measurement mode for measuring altitude and a threshold measurement mode for generating a threshold value.

Next, when the altitude measurement mode is selected, the radio altimeter can transmit the RF signal (S602) and receive the reflected signal from the surface or the structure in response thereto (S603).

Next, when the radio altimeter receives the reception signal reflected from the ground surface or the structure, it can confirm whether the basic threshold value or the adaptation threshold value is used (S604).

Next, in step S605, the radio altimeter compares the received received signal with the basic threshold value in step S605, and detects the received signal reflected from the ground surface as a result of the comparison in step S606.

At this time, the radio altimeter can judge that the received signal reflected from the ground surface is a received signal when the received signal is larger than the basic threshold as a result of the comparison.

On the other hand, if the adaptive threshold value is used as a result of the verification, the radio altimeter compares the received received signal with the basic threshold value (S607), and the received signal reflected from the ground surface can be detected as a result of the comparison (S608).

At this time, if the received signal is larger than the adaptive threshold value, the radio altimeter can determine that the received signal is a reflected signal from the ground surface, otherwise it can be determined as a peripheral signal.

It is to be understood that the present invention is not limited to these embodiments, and all of the elements constituting the embodiments of the present invention described above are described as being combined or operated together. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. In addition, although all of the components may be implemented as one independent hardware, some or all of the components may be selectively combined to perform a part or all of the functions in one or a plurality of hardware. As shown in FIG. In addition, such a computer program may be stored in a computer-readable medium such as a USB memory, a CD disk, a flash memory, etc., and read and executed by a computer, thereby implementing embodiments of the present invention. As the storage medium of the computer program, a magnetic recording medium, an optical recording medium, a carrier wave medium, or the like may be included.

While the invention has been shown and described with reference to certain embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. 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.

110: transmitting antenna
120: receiving antenna
130: Transmitting /
140: Signal processor
150:

Claims (10)

A transmitting and receiving unit transmitting an RF (Radio Frequency) signal through an antenna mounted on one side of a flying object and collecting a reception signal reflected from the ground surface or the structure in response thereto;
A signal processor for converting the collected reception signal into an intermediate frequency (IF) band; And
And generating an adaptive threshold using the converted received signal and detecting a reception signal reflected from the surface of the reception signal collected through the antenna using a preliminarily generated basic threshold value or the adaptive threshold value according to the altitude measurement mode A control unit;
, Wherein the control unit
And determining the use of the adaptive threshold by determining that there is an influence on the structure if the magnitude of the received signal is greater than the basic threshold,
And determines the use of the basic threshold value by determining that there is no influence on the structure if the magnitude of the received signal is smaller than the basic threshold value. The method according to claim 1,
The transmitting /
Wherein the ground wave propagation path is excluded according to the threshold measurement mode, and the received signal is collected for the structure mounted on the other side of the flying object for each RF transmission output. 3. The method of claim 2,
Wherein,
Wherein the adaptive threshold value is generated using a received signal reflected from the structure, and a value obtained by adding a predetermined size to a magnitude of a received signal reflected from the structure over time is generated as the adaptive threshold value. The method of claim 3,
Wherein,
A predetermined size is added to the size of the received signal reflected from the structure over time,
And performs smoothing processing using a maximum value based on the added value to generate the smoothed value as the adaptive threshold value. delete Transmitting an RF (Radio Frequency) signal through an antenna mounted on one side of a flying object and collecting a reception signal reflected from the ground surface or the structure in response thereto;
Converting the collected reception signals into IF (Intermediate Frequency) bands; And
And generating an adaptive threshold using the converted received signal and detecting a reception signal reflected from the surface of the reception signal collected through the antenna using a preliminarily generated basic threshold value or the adaptive threshold value according to the altitude measurement mode step;
, The detecting step
And determining the use of the adaptive threshold by determining that there is an influence on the structure if the magnitude of the received signal is greater than the basic threshold,
And determining the use of the basic threshold value by determining that there is no influence on the structure if the magnitude of the received signal is smaller than the basic threshold value. The method according to claim 6,
Wherein the collecting comprises:
Wherein the ground wave propagation path is excluded according to the threshold measurement mode and the reception signal for the structure mounted on the other side of the air vehicle is collected for each RF transmission output. 8. The method of claim 7,
Wherein the detecting comprises:
Wherein the adaptive threshold value is generated using a received signal reflected from the structure, and a value obtained by adding a predetermined size to a magnitude of a received signal reflected from the structure over time is generated as the adaptive threshold value. How to operate. 9. The method of claim 8,
Wherein the detecting comprises:
A predetermined size is added to the size of the received signal reflected from the structure over time,
And a smoothing process is performed on the maximum value based on the added value and the smoothed value is generated as the adaptive threshold value. delete
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090006543A (en) * 2007-07-12 2009-01-15 주식회사 토비스 A source of light type touch sensing method, touch panel and the system
KR101335503B1 (en) * 2013-03-26 2013-12-02 국방과학연구소 Radio altimeter efficiency analysis system and operation algorism therefor
KR101387664B1 (en) * 2013-04-10 2014-04-29 한국과학기술원 A terrain-aided navigation apparatus using a radar altimeter based on the modified elevation model
KR20140102452A (en) * 2013-02-14 2014-08-22 삼성탈레스 주식회사 Apparatus for laser range finder and method for estimating laser range

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090006543A (en) * 2007-07-12 2009-01-15 주식회사 토비스 A source of light type touch sensing method, touch panel and the system
KR20140102452A (en) * 2013-02-14 2014-08-22 삼성탈레스 주식회사 Apparatus for laser range finder and method for estimating laser range
KR101335503B1 (en) * 2013-03-26 2013-12-02 국방과학연구소 Radio altimeter efficiency analysis system and operation algorism therefor
KR101387664B1 (en) * 2013-04-10 2014-04-29 한국과학기술원 A terrain-aided navigation apparatus using a radar altimeter based on the modified elevation model

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