KR101040261B1 - Apparatus and method for measuring alitude of flying object - Google Patents

Apparatus and method for measuring alitude of flying object Download PDF

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KR101040261B1
KR101040261B1 KR1020100083414A KR20100083414A KR101040261B1 KR 101040261 B1 KR101040261 B1 KR 101040261B1 KR 1020100083414 A KR1020100083414 A KR 1020100083414A KR 20100083414 A KR20100083414 A KR 20100083414A KR 101040261 B1 KR101040261 B1 KR 101040261B1
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South Korea
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frequency
signal
jamming
unit
section
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KR1020100083414A
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Korean (ko)
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이호준
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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
    • G01S13/02—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
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • 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
    • 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
    • G01S7/021—Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
    • 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
    • G01S7/38—Jamming means, e.g. producing false echoes

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for measuring altitude of a vehicle, and more particularly, to an apparatus and method for measuring altitude of a vehicle capable of detecting whether jamming is affected and detecting a frequency band of a jamming signal. The apparatus for measuring altitude of a vehicle according to the present invention includes a generator for generating a frequency signal while sweeping a frequency signal for measuring the altitude of a vehicle; A transmitter for transmitting the frequency signal to the ground when the switch is on; A receiver which receives a reflected signal in which the frequency signal transmitted from the transmitter is reflected by the ground; A detector for detecting a bit frequency that is a difference between a frequency signal of the generator and a reflected signal of the receiver, or detecting a difference frequency of a frequency signal of the generator and a jamming signal received by the receiver; And comparing the magnitude of the bit frequency with a preset intermediate frequency to control the sweep slope of the frequency signal generated by the generator, and if the jamming signal is affected by the bit frequency, turning off the switch. A processor for detecting a frequency section of the jamming signal by comparing the difference frequency output from the detector corresponding to each section after generating the frequency signal in a plurality of sections in each period; It is configured to include.

Description

Apparatus and method for measuring the altitude of an aircraft {APPARATUS AND METHOD FOR MEASURING ALITUDE OF FLYING OBJECT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for measuring altitude of a vehicle, and more particularly, to an apparatus and method for measuring altitude of a vehicle capable of detecting whether jamming is affected and detecting a frequency band of a jamming signal.

The radio altimeter is used to measure the altitude from the ground provided in an aircraft or the like, and a frequency modulation continous wave (FMCW) method is used. The FMCW method transmits a frequency-swept continuous wave and obtains the altitude of the vehicle from the frequency difference between the transmitted signal and the reflected signal.

When the jamming signal is introduced, the radio altimeter causes an error in the measured altitude value. In order to prevent an error of the altitude value, an alternative to detecting and responding to the jamming signal is needed. There is a situation.

The present invention is to solve the above-mentioned conventional problems, an object of the present invention is to detect whether the jamming signal is introduced, and furthermore an apparatus and method for measuring the altitude of the aircraft capable of detecting the frequency band of the jamming signal. To provide.

In accordance with a preferred embodiment of the present invention, an apparatus for measuring an altitude of an aircraft includes: a generator configured to generate a frequency signal for measuring an altitude of an aircraft while frequency sweeping; A transmitter for transmitting the frequency signal to the ground when the switch is on; A receiver which receives a reflected signal in which the frequency signal transmitted from the transmitter is reflected by the ground; A detector for detecting a bit frequency that is a difference between a frequency signal of the generator and a reflected signal of the receiver, or detecting a difference frequency of a frequency signal of the generator and a jamming signal received by the receiver; And comparing the magnitude of the bit frequency with a preset intermediate frequency to control the sweep slope of the frequency signal generated by the generator, and if the jamming signal is affected by the bit frequency, turning off the switch. A processor for detecting a frequency section of the jamming signal by comparing the difference frequency output from the detector corresponding to each section after generating the frequency signal in a plurality of sections in each period; Characterized in that configured to include.

Method for measuring the altitude of the aircraft according to a preferred embodiment of the present invention for achieving the above object, (a) the generation unit generating a frequency signal (sweep) while sweeping the frequency signal for the altitude measurement of the aircraft; (b) a transmitting unit transmitting the frequency signal to the ground; (c) a receiving unit receiving a reflected signal in which the frequency signal transmitted from the transmitter is reflected on the ground and returned; (d) a detector detecting a bit frequency that is a difference between a frequency signal of the generator and a reflected signal of the receiver; (e) the processor comparing the magnitude of the bit frequency with a preset intermediate frequency to generate a command for controlling a sweep slope of the frequency signal and supplying the generated command to the generation unit; And (f) if the processor determines that the jamming signal is affected by the bit frequency, the generation unit divides the frequency signal into a plurality of sections for each period, and prevents the signal from being sent to the ground. Detecting a frequency section of a jamming signal by comparing a difference frequency of a signal from the detection unit; .

According to the present invention having the above-described configuration and method, it is possible to detect whether the jamming signal is affected and to detect the frequency band of the jamming signal, thereby increasing the reliability of the altitude measurement of the aircraft.

1 is a view for explaining a method of measuring the altitude of the vehicle.
Figure 2 is a block diagram schematically showing an altitude measuring apparatus according to a preferred embodiment of the present invention.
3 is a block diagram illustrating the altitude measuring apparatus of FIG. 2 in more detail.
4 is a block diagram illustrating an example in which the altitude measuring apparatus of FIG. 3 is specifically implemented.
FIG. 5 is a graph illustrating an example of a frequency of a transmission signal, a frequency of a reception signal, a frequency of a jamming signal, and a bit frequency when the jamming signal is affected in the altitude measuring apparatus of FIG. 4. FIG.
6 is a block diagram sequentially illustrating a method for measuring altitude according to a preferred embodiment of the present invention.

Hereinafter, an apparatus and method for measuring an altitude of a vehicle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[Altitude measurement device of a vehicle]

First, an altitude measuring apparatus of a vehicle according to a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 5.

As shown in FIG. 2 and FIG. 3, the apparatus for measuring the altitude of a vehicle according to a preferred embodiment of the present invention includes a generator 100 which generates a frequency signal while sweeping a frequency signal for measuring an altitude h of the vehicle. ; A transmitter 200 for transmitting the frequency signal to the ground when the switch is turned on; A receiver 300 for receiving a reflected signal in which the frequency signal transmitted from the transmitter 200 is reflected on the ground and returned; Detect the bit frequency that is the difference between the frequency signal of the generator 100 and the reflected signal of the receiver 300, or the difference frequency of the jamming signal received by the frequency signal of the generator 100 and the receiver 300 Detecting unit 400 for detecting; And controlling the sweep slope of the frequency signal generated by the generator 100 by comparing the magnitude of the bit frequency with the magnitude of a preset intermediate frequency F 0 , and if it is determined that the jamming signal is affected by the bit frequency. After the switch is turned off and the frequency signal is generated by dividing the frequency signal into a plurality of sections in each period, the difference frequency output from the detector 400 corresponding to each section is compared to the jamming signal. A processor 500 for detecting a frequency section; .

Before describing each component of the apparatus for measuring the altitude of the aircraft according to the preferred embodiment of the present invention having such a configuration, the method for measuring the altitude h of the vehicle will be briefly described.

FIG. 1 is a view for explaining a method of measuring the altitude h of the vehicle 10.

As shown in (a) of FIG. 1, the aircraft 10 transmits a signal toward the ground, receives the reflected signal reflected back to the ground, and takes a signal to send the signal to receive the reflected signal. The distance between itself and the ground, i.e., the altitude h, is measured using the time interval T d and the transmitted and reflected signals.

As shown in FIG. 1, the signal transmitted by the vehicle 10 is a sweep frequency signal that is linear in frequency and continuously changes. This sweep frequency signal changes periodically and has a sweep period T. Thus, if the graph shown in Fig. 1B is extended on the time t axis, the sweep frequency signal will appear as a saw-tooth wave. In the following description of the present invention, the sweep frequency signal will be referred to as a frequency signal.

The time interval T d from the time at which the signal is transmitted by the vehicle 10 to the reception of the signal reflected on the ground, and the frequency of the frequency signal swept during the time interval T d and the reflected signal reflected on the ground. The altitude h of the vehicle 10 may be calculated using the bit frequency f b , which is a difference in frequency.

That is, the altitude h of the vehicle 10 may be represented by Equation 1 below.

Figure 112010055549047-pat00001

Where c is the speed of propagation

The bit frequency f b may be represented by Equation 2 below.

Figure 112010055549047-pat00002

(Where Δf is a predetermined frequency range that can be used by the frequency protocol, and T is the sweep period of the frequency signal)

When Equation 1 is substituted into Equation 2, Equation 3 below is obtained.

Figure 112010055549047-pat00003

The equation (3) is summarized as shown in the following equation (4) for the altitude (h).

Figure 112010055549047-pat00004

Therefore, by substituting the values and constants measured in Equation 4, the altitude h of the vehicle can be known.

For example, when the bit frequency f b is fixed in Equation 4, the period T is changed as the altitude h is changed to fix the bit frequency f b and the period ( By measuring the T) value, the altitude h value can be detected.

Hereinafter, each component of the altitude measurement apparatus of the aircraft according to the preferred embodiment of the present invention will be described in detail.

Referring to FIG. 2, an apparatus for measuring altitude of a vehicle according to a preferred embodiment of the present invention includes a generator 100, a transmitter 200, a receiver 300, a detector 400, and a processor 500. do.

Referring to FIG. 3, the generator 100 continuously generates a frequency signal while sweeping a frequency signal for measuring an altitude h of the aircraft and supplies the generated frequency signal to the transmitter 200.

The frequency signal is swept in a range Δf with a predetermined period T, and forms a sawtooth-shaped waveform for each period.

In addition, the frequency signal may be generated by being divided into a plurality of sections in each period according to the control of the processing unit 500, and a detailed description thereof will be described in detail with reference to the processing unit 500 below.

The transmitter 200 transmits the frequency signal from the generator 200 to the ground when the switch is turned on, and the transmitter 200 includes the distributor 201, the switch 202, and the like. The first amplifier 203 is configured to be included.

The distribution unit 201 divides and outputs the frequency signal generated by the generation unit 100, and the first amplifier 203 amplifies and outputs the output of the distribution unit 201 and switches the switching unit ( 202 is disposed between the distribution unit 201 and the first amplifier 203 to turn on or off to perform a connection between the first amplifier 203 and the distribution unit 201, or Disconnect.

The receiver 300 receives a reflected signal from which the frequency signal transmitted from the transmitter 200 is reflected on the ground and returns, and the receiver 300 includes a second amplifier 301 and a mixer 302. It is configured by.

The second amplifier 301 amplifies the received reflected signal but minimizes the amplification of the noise included in the reflected signal, and the mixing unit 302 outputs the output of the distribution unit 201 of the transmitter 200. The outputs of the two amplifiers 301 are mixed and output to the detector 400.

When the switching unit 202 of the transmitter 200 is turned on, the receiver 300 outputs a bit frequency signal obtained by mixing a reflected signal and a frequency signal, and the switching unit 202 of the transmitter 200. When () is off (off) outputs the difference frequency signal of the jamming signal and the frequency signal mixed, a detailed description thereof will be described in detail for the detection unit 400 below.

The detector 400 receives a bit frequency signal from the receiver 300 and detects and outputs a bit frequency f b , or detects and outputs a difference frequency by receiving a difference frequency signal from the receiver 300. The detector 400 includes a frequency discriminating unit 401 and an analog-digital converting unit 402.

The frequency discriminating unit 401 converts the frequency information of the signal input from the mixing unit 302 of the receiving unit 300 into amplitude information, and outputs it. The analog-digital converting unit 402 is the frequency discriminating unit 401. Outputs the bit frequency (or difference frequency) obtained by converting the output of the digital signal into a digital signal. At this time, the bit frequency f b is output to the processing unit 500 to be described later during the output of the analog-digital converting unit 402, and the processing unit 500 converts the received bit frequency f b into the memory unit 501. Store in the space corresponding to the time of the frequency signal being swept.

When the switching unit of the transmitter 200 is turned on, the detector 400 receives a bit frequency signal from the mixing unit 302 of the receiver 300 and detects and outputs a bit frequency f b . When the switching unit 202 of the transmitter 200 is turned off, the difference frequency signal is received from the mixing unit 302 of the receiver 300 to detect and output the difference frequency. In the description of the detection unit 400 will be described in detail.

The processing unit 500 includes a memory unit 501, a digital signal processing unit 502, and a time control unit (not shown), and the digital signal processing unit 502 includes a bit frequency f b stored in the memory unit 501. ) Is compared with the size of the preset intermediate frequency (F 0 ), if it is determined that there is a difference, by controlling the frequency sweep slope of the frequency signal generated by the generator 100 to be the same, judged to be the same The altitude value of the aircraft is calculated and output using the magnitude of the bit frequency f b and the time interval T d . In addition, when it is determined that the jamming signal is affected by the bit frequency f b stored in the memory unit 501, the digital signal processing unit 502 of the processing unit 500 turns off the switching unit 202. After generating the frequency signal by dividing the frequency signal into a plurality of sections in each period, the generation unit 100 compares the difference frequency, which is the output of the detection unit 400 corresponding to each section, and detects the frequency section of the jamming signal.

The processing unit 500 will be described in more detail as follows.

The processor 500 compares the size of the bit frequency f b stored in the memory unit 501 with a preset intermediate frequency F 0 so that the size of the bit frequency f b is the intermediate frequency F. If it is determined to be greater than the magnitude of 0 ), a command to reduce the frequency sweep slope of the frequency signal is transmitted to the generation unit 100, and the magnitude of the bit frequency f b is smaller than the intermediate frequency F 0 . If it is determined that the bit frequency f b is closer to the intermediate frequency F 0 by transmitting a command to increase the frequency sweep slope of the frequency signal to the generation unit 100, the bit frequency f b. ) And the magnitude of the intermediate frequency (F 0 ) is equal to the altitude value of the aircraft using the size and time interval (T d ) of the bit frequency f b stored in the memory unit 501 Output In this case, the intermediate frequency F 0 is a preset value, which is an ideal value as a difference between the frequency signal of the generator 100 and the reflected signal of the receiver 300.

In addition, the processing unit 500 has a jamming period in which there is a fluctuation among a plurality of sections forming one period of the bit frequency f b stored in the memory unit 501, and thus the jamming signal is affected. When it is determined that there is an influence of the jamming signal in the section corresponding to the jamming section even in the next period, the switching unit 202 is turned off, and the frequency generating unit 100 generates a plurality of frequency signals in each period. After it is generated by dividing the interval, if it is determined that the RMS value (signal effective magnitude) of the difference frequency, which is the output of the detection unit 400 corresponding to each interval, is greater than the jamming level, it is determined and output as the frequency interval of the jamming signal. In this case, the jamming level is a minimum level that may affect the result of measuring the altitude by the altitude measuring apparatus of the aircraft, and is stored in advance in the memory.

When the altitude measurement apparatus of the aircraft according to the present invention determines and outputs the frequency section of the jamming signal as described above, it is not a height (h) measured by itself, but a global positioning system (GPS) or an inertial navigation system (INS). It is possible to increase the reliability of the aircraft by allowing the aircraft to use the altitude (h) supplied from other equipment.

4 is a block diagram showing a specific implementation of the altitude measurement apparatus of the vehicle according to the preferred embodiment of the present invention as shown in Figs. 2 and 3, Figure 5 shows the jamming signal in the altitude measurement apparatus of FIG. An example of the frequency of the transmission signal (ie, the frequency signal), the frequency of the received signal (ie, the reflected signal), the frequency of the jamming signal, and the bit frequency f b when there is an effect is shown.

Referring to FIG. 4, an apparatus for measuring altitude of an aircraft according to an exemplary embodiment of the present invention may include an oscillator 112, a direct digital synthesizer 111, a band pass filter 113, and a first passometer. Mixer 114, frequency generator 115, coupler 211, switch 212, first amplifier AMP, 213, transmit antenna 214, receive antenna 313, second amplifier (LNA, 311), second mixer 312, high pass filter (413), low pass filter (414), frequency discriminator (411), analog-to-digital converter (analog) and a digital converter 412, a digital signal processor 512, a random access memory 511, and a timer 513.

4 and 5, the DDS 111 generates a sweep frequency signal whose frequency increases with time in synchronization with the oscillator 112. The frequency signal is implemented as a frequency signal having one sweep in one cycle, and is typically in the form of a sawtooth wave.

The band pass filter 113 may be provided to remove digital quantization noise of a frequency signal, and the frequency signal passing through the band pass filter 113 is input to the first mixer 114.

In the first mixer 114, the sweep frequency signal and the carrier frequency signal generated by the frequency oscillator 115 are mixed. Here, the frequency oscillator 115 may be typically implemented as a local oscillator.

The coupler 211 transmits the mixed transmit frequency signal from the first mixer 114 to the first amplifier 213 through the switch 212, and the amplified transmit frequency signal is transmitted to the ground through the transmit antenna 214. It is sent out. On the other hand, the coupler 211 transmits the transmission frequency signal to the second mixer 312. That is, when the switch 212 is turned on, the transmission frequency signal is transmitted to the ground through the first amplifier 213 and the transmission antenna 214 and is also transmitted to the second mixer 312, and the switch ( When 212 is off, it is transmitted only to the second mixer 312.

The reflection signal transmitted from the transmission antenna 214 and reflected on the ground is input to the reception antenna 313, and the reflection signal has a predetermined time interval T d from the transmission frequency signal. The reflected signal is amplified by the second amplifier 311, and the amplified reflected signal is transmitted to the second mixer 312.

The second mixer 312 generates a bit frequency f b signal by mixing the transmission frequency signal branched from the coupler 211 and the amplified reflection signal. In this case, when the switch 212 is turned on, the second mixer 312 outputs a bit frequency signal obtained by mixing the reflection signal and the transmission frequency signal as described above, but the switch 212 is turned off ( When off), a difference frequency signal obtained by mixing a jamming signal and a transmission frequency signal is output. A detailed description thereof will be provided later in the description of the DSP 512.

The frequency discriminator 411 outputs an amplitude signal obtained by converting frequency information of a signal input from the second mixer 312 into amplitude information, and the analog-digital converter 412 of the frequency discriminator 411 Outputs the bit frequency (or difference frequency) obtained by converting the output into a digital signal. At this time, the analog-to-digital converter 411 transmits the bit frequency f b converted into a digital signal to the DSP 512 to be stored in the RAM 511.

The frequency discriminator 411 and the analog-to-digital converter 412 detect a bit frequency f b by receiving a bit frequency signal from the second mixer 312 when the switch 212 is turned on. When the switch 212 is off (off), and receives the difference frequency signal from the second mixer 312 to detect and output the difference frequency, a detailed description thereof will be described below for the DSP 512 This will be explained in detail.

The DSP 512 calculates an altitude h value of the vehicle using the bit frequency f b and the time interval T d stored in the RAM 511.

In addition, the DSP 512 compares the magnitude of the bit frequency f b stored in the RAM 511 with the magnitude of the preset intermediate frequency F 0 , so that the magnitude of the bit frequency f b is the intermediate frequency F. If it is determined to be greater than the magnitude of 0 ), a command to reduce the frequency sweep slope of the frequency signal is transmitted to the DDS 111, and it is determined that the magnitude of the bit frequency f b is smaller than the intermediate frequency F 0 . In this case, by transmitting a command to the DDS 111 to increase the frequency sweep slope of the frequency signal, the bit frequency f b becomes close to the intermediate frequency F 0 . In this case, the intermediate frequency F 0 is a preset value and is an ideal value as a difference between the frequency signal generated by the DDS 111 and the reflected signal received by the receiving antenna 313.

In addition, the DSP 512 has a jamming section in which a plurality of sections forming one period of the bit frequency f b stored in the RAM 511 is fluctuated, and thus there is a jamming section determined to be affected by the jamming signal, and at least two If it is determined that there is an influence of the jamming signal in the section corresponding to the jamming section in the next period, the switch 212 is turned off and the frequency signal is divided into a plurality of sections in each period in the DDS 111. After it is generated, if it is determined that the RMS value (signal effective magnitude) of the difference frequency that is the output of the analog-digital converter 412 corresponding to each section is greater than the jamming level, it is determined and output as the frequency section of the jamming signal. In this case, the jamming level is a minimum level that may affect the result of measuring the altitude by the altitude measuring apparatus of the aircraft, and is stored in advance in the memory.

[Method for Measuring Altitude of a Vehicle]

Hereinafter, a method for measuring altitude of a vehicle according to a preferred embodiment of the present invention will be described with reference to FIGS. 2, 3, and 6.

First, after the system is initialized (S101), the generation unit 100 generates a frequency signal for measuring the altitude h of the vehicle continuously while generating a frequency sweep (S102) and supplies it to the transmission unit 200. (S103)

The frequency signal is swept in a range Δf with a predetermined period T, and forms a sawtooth-shaped waveform for each period.

Next, the transmitter 200 transmits the frequency signal to the ground. In this case, the switching unit 202 of the transmitter 200 is preferably in an on state.

The transmitter 200 includes a distribution unit 201, a switching unit 202, and a first amplifier 203, and the distribution unit 201 receives a frequency signal generated by the generation unit 100. The first amplifier 203 amplifies and outputs the output of the distributor 201, and the switching unit 202 is disposed between the distributor 201 and the first amplifier 203. By being disposed on or off, the connection between the first amplifier 203 and the distribution unit 201 is performed or released.

Next, the receiver 300 receives a reflected signal in which the frequency signal transmitted from the transmitter 200 is reflected by the ground and returns to generate a bit frequency signal in which the transmission frequency signal and the reflected signal are mixed (S104).

The receiver 300 includes a second amplifier 301 and a mixer 302, and the second amplifier 301 amplifies the received reflected signal, but amplifies the noise included in the reflected signal. The mixer 302 mixes the output of the distribution unit 201 of the transmitter 200 and the output of the second amplifier 301 and outputs the mixed signal to the detector 400.

Next, the detector 400 receives the bit frequency signal from the generator 100 to detect and output the bit frequency f b .

The detection unit 400 includes a frequency discriminating unit 401 and an analog-digital converting unit 402, and the frequency discriminating unit 401 is a signal input from the mixing unit 302 of the receiving unit 300. The frequency information is converted into amplitude information and output, and the analog-digital converting unit 402 outputs a bit frequency (or difference frequency) obtained by converting the output of the frequency discriminating unit 401 into a digital signal. At this time, the bit frequency f b is output to the processing unit 500 to be described later during the output of the analog-digital converting unit 402, and the processing unit 500 converts the received bit frequency f b into the memory unit 501. Store in the space corresponding to the time of the frequency signal is the frequency sweep (S110).

Next, the processor 500 compares the size of the bit frequency f b stored in the memory unit 501 with the size of a preset intermediate frequency F 0 (S105), and thus the size of the bit frequency f b . Is determined to be greater than the magnitude of the intermediate frequency F 0 , a command to reduce the frequency sweep slope of the frequency signal is transmitted to the generation unit 100 (S108), and the magnitude of the bit frequency f b is increased. If it is determined that it is smaller than the intermediate frequency F 0 , the bit frequency f b is set to the intermediate frequency F 0 by transmitting a command to increase the frequency sweep slope of the frequency signal to the generation unit 100 (S109). If it is determined that the size of the bit frequency (f b ) and the size of the intermediate frequency (F 0 ) is the same, the size of the aircraft using the size of the bit frequency (f b ) and the time interval (T d ). The altitude value is calculated (S106) and output (S107). In this case, the intermediate frequency F 0 is a preset value, which is an ideal value as a difference between the frequency signal of the generator 100 and the reflected signal of the receiver 300. In addition, the processing unit 500 has a jamming section which is determined to be affected by the jamming signal due to variation in a plurality of sections forming one period of the bit frequency f b stored in the memory unit 501 (S111). In the case where it is determined that there is an influence of the jamming signal in the section corresponding to the jamming section even in at least two next periods (S11), the switching unit 202 is turned off (S113) and the generating unit 100 After the frequency signal is generated by dividing the signal into a plurality of sections in each period (S114), if it is determined that the RMS value (signal effective magnitude) of the difference frequency that is the output of the detection unit 400 corresponding to each section is greater than the jamming level ( S115) Determining that it is a frequency section of the jamming signal and outputting the same (S116) and simultaneously repeats the process of turning off the switching unit 202, and the difference frequency is greater than the effective value of the bit frequency f b . If it is determined that the frequency signal is swept by the frequency signal is repeatedly performed in step (S114) to control the generation unit 100 to generate continuously. In this case, the jamming level is a minimum level that may affect the result of measuring the altitude by the altitude measuring apparatus of the aircraft, and is stored in advance in the memory.

[Recording medium]

On the other hand, the above-described altitude measurement method according to the present invention can be written in a program that can be executed in a computer, it can be implemented in a general-purpose digital computer to operate the program using a computer-readable recording medium. Computer-readable recording media include magnetic storage media (e.g. ROM, floppy disks, hard disks, magnetic data, etc.), optical reading media (e.g. CD-ROMs, DVDs, optical data storage devices, etc.) and carrier waves (e.g., Storage media such as, for example, transmission over the Internet.

100 generation unit 200 transmission unit
300: receiver 400: detector
500 processing unit
201: distributor 202: switching unit
203: first amplifier 301: second amplifier
302: mixing section 401: frequency discriminating section
402: analog-digital converting unit 501: memory unit
502: digital signal processor 111: DDS
112: oscillator 113: bandpass filter
114: first mixer 115: frequency generator
211: coupler 212: switch
213: first amplifier 214: transmitting antenna
311: second amplifier 312: second mixer
313: receiving antenna 411: frequency discriminator
412: analog-digital converting unit 413: high pass filter
414: low pass filter 511: RAM
512: DSP 513: timer

Claims (15)

A generator for generating a frequency signal while sweeping a frequency signal for measuring the altitude of the vehicle;
A transmitter for transmitting the frequency signal to the ground when the switch is on;
A receiver which receives a reflected signal in which the frequency signal transmitted from the transmitter is reflected by the ground;
A detector for detecting a bit frequency that is a difference between a frequency signal of the generator and a reflected signal of the receiver, or detecting a difference frequency of a frequency signal of the generator and a jamming signal received by the receiver; And
The sweep slope of the frequency signal generated by the generator is compared by comparing the magnitude of the bit frequency with a preset intermediate frequency, and when the jamming signal is determined to be affected by the bit frequency, the switch is turned off. A processor which detects a frequency section of the jamming signal by comparing the difference frequency output from the detector corresponding to each section after generating the frequency signal in a plurality of sections in each generation section;
Altitude measuring apparatus of the aircraft comprising a. The method of claim 1, wherein when the switch is turned on, the generation unit continuously generates a frequency signal while frequency sweeping to form a sawtooth-shaped waveform at each period, and the switch is turned off. In the case of the altitude measurement apparatus of the aircraft, characterized in that for generating a frequency signal divided into a plurality of sections having a predetermined interval. The method of claim 1, wherein the transmitting unit,
A distribution unit for distributing and outputting a frequency signal generated by the generation unit;
A first amplifier for amplifying and outputting the output of the distribution unit;
A transmission antenna for transmitting the output of the first amplifier to the ground; And
The switch disposed between the distribution unit and the amplifying unit and turned on or off by control of the processing unit;
Altitude measuring apparatus of the aircraft comprising a. The method of claim 3, wherein the receiving unit,
A receiving antenna for receiving the reflected signal returned from the frequency signal transmitted from the transmitter to the ground;
A second amplifier for amplifying and outputting a signal received through the reception antenna; And
A mixing unit for mixing and outputting the output of the distribution unit and the output of the second amplifier unit;
Altitude measurement apparatus of the aircraft, characterized in that configured to include. 5. The receiver of claim 4, wherein the receiver receives the jamming signal through the receiving antenna when the transmitter is switched off, amplifies the signal through the second amplifier, and then mixes and outputs the mixer in the mixer. Altitude measuring device of the aircraft. The method of claim 1, wherein the detection unit,
A high pass filter for filtering a mixed signal of the reflection signal received by the receiver and the frequency signal transmitted by the transmitter;
A low pass filter for filtering the output of the high pass filter;
A frequency discriminating unit converting the frequency information of the output of the low pass filter into amplitude information and outputting the amplitude information; And
An analog-digital converter converting the output of the frequency discriminator into a digital signal and outputting the digital signal;
Altitude measuring apparatus of the aircraft comprising a. The apparatus of claim 1, wherein the detection unit detects a bit frequency and stores the bit frequency in a memory unit provided in the processing unit, and stores the bit frequency in a space corresponding to a time of a frequency signal that is frequency-swept. The jamming section of claim 1, wherein the processing unit has a jamming section in which a jamming signal is affected among a plurality of sections forming one period of a bit frequency, and at least two subsequent periods of the jamming signal in the section corresponding to the jamming section. When it is determined that there is an effect, the switch is turned off and the frequency unit is generated by dividing the frequency signal into a plurality of sections in each period, and then the jamming is performed by comparing the difference frequencies that are outputs of the detection units corresponding to the sections. Altitude measurement apparatus of the aircraft, characterized in that for detecting the frequency section of the signal. The apparatus of claim 8, wherein the processor determines a jamming section among a plurality of sections forming one period of a bit frequency as a jamming section. The RMS value of the difference frequency according to claim 8, wherein the processing unit turns off the switch and causes the frequency signal to be generated by dividing the frequency signal into a plurality of sections in each period, and then outputs an RMS value of a difference frequency corresponding to each section. And determining that the frequency range of the jamming signal is greater than the predetermined jamming level, and outputting the determined jamming signal. (a) generating a frequency signal while sweeping the frequency signal for measuring the altitude of the vehicle;
(b) a transmitting unit transmitting the frequency signal to the ground;
(c) a receiving unit receiving a reflected signal in which the frequency signal transmitted from the transmitter is reflected on the ground and returned;
(d) a detector detecting a bit frequency that is a difference between a frequency signal of the generator and a reflected signal of the receiver;
(e) the processor comparing the magnitude of the bit frequency with a preset intermediate frequency to generate a command for controlling a sweep slope of the frequency signal and supplying the generated command to the generation unit; And
(f) If it is determined that the jamming signal is affected by the bit frequency, the processor generates the frequency signal into a plurality of sections for each period, and prevents the generator from transmitting the signal to the ground. Detecting a frequency interval of a jamming signal by comparing a difference frequency of the signal from the detector;
Altitude measurement method of a vehicle comprising a. The method of claim 11, wherein in step (f),
The processing unit determines that there is a jamming section in which a jamming signal is affected among a plurality of sections forming one period of a bit frequency and that the jamming signal is affected in a section corresponding to the jamming section in at least two subsequent periods. In order to generate the frequency signal divided into a plurality of sections for each period, the generator prevents the generator from transmitting it to the ground, and then compares the frequency difference between the frequency signal and the jamming signal of each section from the detection unit to compare the frequency section of the jamming signal. Altitude measurement method of the aircraft, characterized in that for detecting. The method of claim 12, wherein in step (f),
The processing unit determines the altitude of the aircraft, characterized in that for determining the interval of the jamming section of the plurality of sections forming any one period of the beat frequency. The method of claim 12, wherein in step (f),
If the processor determines that the RMS value of the difference frequency is greater than the predetermined jamming level, the altitude measurement method of the aircraft, characterized in that it is determined to output the frequency section of the jamming signal. A computer-readable recording medium, wherein a program for implementing a method according to any one of claims 11 to 14 is recorded.
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KR101386636B1 (en) 2012-12-18 2014-04-18 국방과학연구소 Least jammed frequency method of radar system and apparatus thereof
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