KR102491948B1 - Method to determine the horizontal speed of ionospheric plasma irregularity using single gnss receiver - Google Patents

Abstract

The present invention relates to a method for determining the velocity of an ionospheric plasma inhomogeneity, and more specifically, band filtering from an L1 channel signal and an L2 channel signal received from a GPS receiver to derive a dither component due to each refraction, and calculating a correlation coefficient A technique for determining the horizontal velocity of ionospheric plasma heterogeneity.

Description

High-latitude ionospheric plasma heterogeneous horizontal speed determination method using a single GNSS receiver

The present invention relates to a method for determining the velocity of an ionospheric plasma inhomogeneity, and more specifically, band filtering from an L1 channel signal and an L2 channel signal received from a GPS receiver to derive a dither component due to each refraction, and calculating a correlation coefficient A technique for determining the horizontal velocity of ionospheric plasma heterogeneity.

The ionosphere is a layer in which the Earth's atmosphere is photoionized by extreme ultra violet rays and X-rays, and exists in the form of electrons and ions, that is, in a plasma state. The ionospheric scintillation phenomenon is a phenomenon in which the amplitude or phase of a radio wave signal passing through an area in which the electron density of the ionosphere is non-uniform changes very rapidly, making it difficult to receive signals normally.

Conventionally, an ionospheric scintillation monitor was used to observe this ionospheric scintillation phenomenon. An ionospheric scintillation monitor is a device that receives a GPS signal with a high time resolution of 50 Hz or more and 100 Hz or less in order to observe ionosphere scintillation.

However, in order to analyze the ionosphere more precisely through the ionospheric scintillation monitor, the speed of the plasma in an area with non-uniform electron density and various parameters resulting therefrom must be derived, but it is still difficult to infer the speed of the ionosphere plasma.

Korean Registered Patent No. 10-0129134 (“Ionosphere electron count monitoring device”, 1997.11.07.)

The present invention has been made to solve the above problems, and by band-filtering the L1 channel signal and the L2 channel signal using a Fresnel frequency according to the expected plasma speed, phase shaking signals due to refraction are extracted, respectively, and the L1 channel signal and The present invention relates to a method for determining an ionospheric plasma heterogeneous horizontal direction speed, in which an expected plasma speed that meets a condition is determined as the plasma speed according to a correlation coefficient of a phase shake signal of an L2 channel signal and a phase component ratio.

In order to solve the above problems, the present invention relates to a method for inferring ionospheric plasma speed, and more specifically, a processor receives a first channel signal (L ₁ ) and a second channel signal (L ₂ ) from a GPS receiver (a) and (b) filtering the first channel signal (L ₁ ) and the second channel signal (L ₂ ) based on a predetermined expected plasma velocity (v _p ), respectively, to obtain a first filter output signal (L _1B ). ) and calculating the second filter output signal (L _2B ), and (c) calculating the correlation coefficient (C) between the first filter output signal (L _1B ) and the second filter output signal (L _2B ). and (d) repeatedly performing steps (b) and (c) while changing the expected plasma speed (v _p ), and performing the step (c) according to the changed expected plasma speed (v _p ). and storing the correlation coefficient (C) calculated in , and providing the expected plasma speed (v _p ) at which the correlation coefficient (C) is maximized as a plasma speed estimation value (v).

In the step (b), a first band filter for calculating a first filter output signal (L _1B ) by band-filtering the first channel signal (L ₁ ) based on a first predetermined Fresnel frequency (f ₁ ). (B ₁ ) and band-filtering the second channel signal (L ₂ ) based on a predetermined second Fresnel frequency (f ₂ ) to calculate a second filter output signal (L _2B ). It is characterized by band filtering with a band filter (B ₂ ).

The band of the first band filter (B ₁ ) is equal to or greater than 0.1 Hz and equal to or less than the first Fresnel frequency (f ₁ ), and the band of the second band filter (B ₂ ) is greater than or equal to 0.1 Hz to the second Fresnel frequency (f 1 ). f ₂ ) or less.

The first Fresnel frequency f ₁ is calculated based on Equation 1 below, and the second Fresnel frequency f ₂ is calculated based on Equation 2 below.

The frequency of the first channel signal (L ₁ ) is 1575.42 MHz, and the frequency of the second channel signal (L ₂ ) is 1227.60 MHz.

The correlation coefficient (C) is characterized in that it is calculated based on Equation 3 below.

The step (d) is characterized in that steps (b) and (c) are repeatedly performed while increasing the expected plasma speed (v _p ) by 10 m/s.

The initial value of the expected plasma speed (?? _?? ) is 100 m/s, and the maximum value is 2000 m/s.

In the step (d), the correlation coefficient (C) according to the changed expected plasma speed (v _p ) is 0.9 or more, and the component ratio is 1.3 or more and 1.9 or less, among the expected plasma speeds (v _p ), the correlation coefficient ( C) is characterized in that the expected plasma speed (v _p ) at which maximum is provided as the plasma heterogeneous horizontal direction speed estimate value (v).

The present invention according to the above configuration has an effect of more accurately deriving parameters necessary for ionosphere analysis by determining the plasma speed of the high latitude ionosphere having a non-uniform electron density.

1 is a flow chart of a preferred ionospheric plasma speed determination method of the present invention
2 is a block diagram of a preferred ionosphere plasma speed determination method of the present invention
3 is a flowchart of a specific ionospheric plasma speed determination method of the present invention

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, it should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, the technical idea of the present invention will be described in more detail using the accompanying drawings.

Since the accompanying drawings are only examples shown to explain the technical idea of the present invention in more detail, the technical idea of the present invention is not limited to the form of the accompanying drawings.

The present invention relates to a method for determining the speed of electrons by using the dither component due to refraction by applying the reverse method of extracting the dither component due to refraction when the speed of electrons in the ionosphere is known.

In summary, as shown in FIG. 1, the L1 channel signal and the L2 channel signal are band-filtered using the Fresnel frequency according to the expected plasma speed to extract phase shift signals due to refraction, respectively, and the L1 channel signal and the L2 channel signal An expected plasma speed that meets the conditions is determined as the plasma inhomogeneity speed according to the correlation coefficient of the signal and the phase component ratio of the signal.

More specifically, as shown in FIG. 1, a processor receives (a) a first channel signal (L ₁ ) and a second channel signal (L ₂ ) from a GPS receiver; and (b) a predetermined Based on the expected plasma speed (v _p ), the first channel signal (L ₁ ) and the second channel signal (L ₂ ) are filtered, respectively, to obtain a first filter output signal (L _1B ) and a second filter output signal (L ). _2B ), (c) calculating a correlation coefficient (C) between the first filter output signal (L _1B ) and the second filter output signal (L _2B ), and (d) the plasma Steps (b) and (c) are repeatedly performed while changing the expected speed (v _p ), and the correlation coefficient (C) calculated in step (c) according to the changed expected speed (v _p ) of the plasma is and providing the expected plasma speed (v _p ) at which the correlation coefficient (C) is maximized as a plasma heterogeneity speed estimation value (v).

In the step (b), a first band filter for calculating a first filter output signal (L _1B ) by band-filtering the first channel signal (L ₁ ) based on a first predetermined Fresnel frequency (f ₁ ). (B ₁ ) and band-filtering the second channel signal (L ₂ ) based on a predetermined second Fresnel frequency (f ₂ ) to calculate a second filter output signal (L _2B ). It is characterized by band filtering with a band filter (B ₂ ).

The band of the first band filter (B ₁ ) is equal to or greater than 0.1 Hz and equal to or less than the first Fresnel frequency (f ₁ ), and the band of the second band filter (B ₂ ) is greater than or equal to 0.1 Hz to the second Fresnel frequency (f 1 ). f ₂ ) or less.

The first Fresnel frequency f ₁ is calculated based on Equation 1 below, and the second Fresnel frequency f ₂ is calculated based on Equation 2 below.

The frequency of the first channel signal (L ₁ ) is 1575.42 MHz, and the frequency of the second channel signal (L ₂ ) is 1227.60 MHz.

In other words, the first channel signal L ₁ may be an L1 channel signal having a frequency of 1575.42 MHz in the ionosphere, and the second channel signal L ₂ may be an L2 channel signal having a frequency of 1227.60 MHz in the ionosphere. .

)은 약 0.19m이고, 제 2 채널 신호(L₂)의 파장(

)은 약 0.24m일 수 있다. 또한, 전리권의 고도(z)는 통상 350km으로 가정한다. Therefore, the wavelength of the first channel signal (L ₁ ) (

) is about 0.19 m, and the wavelength of the second channel signal (L ₂ ) (

) may be about 0.24 m. In addition, it is assumed that the altitude (z) of the ionosphere is normally 350 km.

On the other hand, at high latitudes, the Fresnel frequency increases because the speed of electrons in the ionosphere is very fast. Here, the refractive component causes a shaking phenomenon in the phase of the signal. In the high latitude region, only the high-frequency dither at or above the Fresnel frequency is a diffraction component, and the diffraction at a lower frequency is a refraction component. Therefore, it is preferable that the bandwidth of the band filter is greater than or equal to 0.1 Hz and less than or equal to the Fresnel frequency, and only the phase refraction component of the signal remains in the channel signal passing through the band filter.

In other words, the bands of the first and second band filters B ₁ and B ₂ will be determined according to the first Fresnel frequency f ₁ and the second Fresnel frequency f ₂ calculated by Equations 1 and 2 above. can

In addition, the first filter output signal (L _1B ) calculated by passing the first channel signal (L ₁ ) through the first band filter (B ₁ ) and performing band-pass filtering by the processor has a phase shift of the first channel signal (L ₁ ). The second filter output signal (L _2B ) calculated by passing the second channel signal (L ₂ ) through the second band filter (B ₂ ) and band-filtering the second channel signal (L ₂ ) includes the phase of the second channel signal (L 2 ). It may contain a tremor component.

At this time, the phase shaking components due to refraction of the first channel signal (L ₁ ) and the second channel signal (L ₂ ) have a high correlation coefficient and a constant phase component ratio (L ₂ /L ₁ ).

The correlation coefficient (C) is characterized in that it is calculated based on Equation 3 below.

In addition, the phase component ratio (L ₂ /L ₁ ) can be obtained as a ratio of the second filter output signal (L _2B ) to the first filter output signal (L _1B ). That is, it is calculated by dividing the second filter output signal (L _2B ) by the first filter output signal (L _1B ).

The step (d) is characterized in that steps (b) and (c) are repeatedly performed while increasing the expected plasma speed (v _p ) by 10 m/s.

The initial value of the expected plasma speed (?? _?? ) is 100 m/s, and the maximum value is 2000 m/s.

Plasma in the ionosphere usually has a speed of 100 m/s or more and 2000 m/s or less at high latitudes.

In the step (d), the correlation coefficient (C) according to the changed expected plasma speed (v _p ) is 0.9 or more, and among the expected plasma speeds (v _p ) where the phase component ratio is 1.3 or more and 1.9 or less, the correlation coefficient It is characterized in that (C) provides the plasma expected speed (v _p ) at which maximum is provided as the plasma heterogeneous speed estimation value (v).

Hereinafter, the operation of the present invention will be described in detail with reference to FIGS. 1 to 3.

= 0.19m) 및 전리권의 고도(z=350km)를 상기 수식 1에 대입하여 계산한 제 1 프레넬 주파수(f₁)는 약 0.274Hz이며, 제 2 채널 신호의 파장(

= 0.24m) 및 전리권의 고도(z=350km)를 상기 수식2에 대입하여 계산한 제 2 프레넬 주파수(f₂)는 약 0.244Hz이다. 제 1 및 2 프레넬 주파수가 계산됨에 따라 제 1 및 2 대역 필터의 대역이 정해진다. 즉, 제 1 대역 필터(B₁)의 대역은 0.1Hz 이상 0.274Hz 이하이며, 제 2 대역 필터(B₂)의 대역은 0.1Hz 이상 0.244Hz 이하이다. 프로세서는 GPS 수신기로부터 수신한 제 1 채널 신호(L₁)를 제 1 대역 필터(B₁)로 필터링한 제 1 필터 출력 신호(L_1B)를 산출하고, 제 2 채널 신호(L₂)를 제 2 대역 필터(B₂)로 필터링한 제 2 필터 출력 신호(L_2B)를 산출한다. 프로세서는, 제 1 및 2 필터 출력 신호를 수식 3에 대입하여 상관관계(C)를 산출한다. 이 값을 C₁₀₀이라고 하자. 프로세서는 C₁₀₀를 상관관계 데이터베이스(130)에 저장한다. 또한, 프로세서는 제 1 및 2 필터 출력 신호에 대한 위상 성분 비율(L₂/L₁)를 산출한다. 이 값을 L₂/L_{1_100}이라고 하자. 프로세서는 L₂/L_{1_100}을 비율 데이터베이스(140)에 저장한다. After the processor sets the expected plasma speed (v _p ) to an initial value of 100 m/s, the wavelength of the first channel signal (

= 0.19m) and the altitude of the ionosphere (z = 350 km) calculated by substituting the above Equation 1, the first Fresnel frequency (f ₁ ) is about 0.274 Hz, and the wavelength of the second channel signal (

= 0.24 m) and the altitude of the ionosphere (z = 350 km) into Equation 2, the second Fresnel frequency (f ₂ ) is about 0.244 Hz. As the first and second Fresnel frequencies are calculated, bands of the first and second band filters are determined. That is, the band of the first band filter (B ₁ ) is greater than or equal to 0.1 Hz and less than or equal to 0.274 Hz, and the band of the second band filter (B ₂ ) is greater than or equal to 0.1 Hz and less than or equal to 0.244 Hz. The processor calculates a first filter output signal (L _1B ) obtained by filtering the first channel signal (L ₁ ) received from the GPS receiver with a first band filter (B ₁ ), and generates a second channel signal (L ₂ ). A second filter output signal (L _2B ) filtered by a two-band filter (B ₂ ) is calculated. The processor calculates the correlation (C) by substituting the first and second filter output signals into Equation 3. Let's call this value C ₁₀₀ . The processor stores C ₁₀₀ in the correlation database 130 . Also, the processor calculates a phase component ratio (L ₂ /L ₁ ) for the first and second filter output signals. Let's call this value L ₂ /L _{1_100} . The processor stores L ₂ /L _{1_100} in the ratio database 140 .

Next, the processor sets the expected plasma speed (v _p ) to 110 m/s, which is increased by 10 m/s, and then repeats the above process. The processor stores C ₁₁₀ in the correlation database 130 and stores L ₂ /L _{1_110} in the ratio database 140 .

In this way, the processor increases the expected plasma speed (v _p ) by 10 m/s and repeats until the expected plasma speed (v _p ) reaches 2000 m/s. C ₁₀₀ to C ₂₀₀₀ are stored in the correlation database 130 , and L ₂ /L _{1_100} to L ₂ /L _{1_2000} are stored in the ratio database 140 . The speed calculator 150 calculates the expected plasma speed (v) at which the correlation coefficient (C) is the maximum among the expected plasma speeds (v _p ) in which the correlation coefficient (C) is 0.9 or more and the phase component ratio is 1.3 or more and 1.9 or less. _p ) as the plasma inhomogeneity velocity estimate (v).

With this configuration, the speed of plasma heterogeneity in the ionosphere can be determined.

The present invention is not limited to the above embodiments, and the scope of application is diverse, and various modifications and implementations are possible without departing from the gist of the present invention claimed in the claims.

50: GPS receiver
100: processor
B ₁ : first band filter
B ₂ : second band filter
130: correlation database
140: ratio database
150: speed calculation unit

Claims (9)

processor,
(a) receiving a first channel signal (L ₁ ) and a second channel signal (L ₂ ) from a GPS receiver;
(b) filtering the first channel signal (L ₁ ) and the second channel signal (L ₂ ) based on a predetermined expected plasma speed (v _p ), respectively, to obtain a first filter output signal (L _1B ) and a second channel signal (L 2 ). calculating a filter output signal (L _2B );
(c) calculating a correlation coefficient (C) between the first filter output signal (L _1B ) and the second filter output signal (L _2B ); and
(d) Steps (b) and (c) are repeatedly performed while changing the expected plasma speed (v _p ), and the correlation calculated in step (c) according to the changed expected plasma speed (v _p ) Storing a coefficient (C) and providing the expected plasma velocity (v _p ) at which the correlation coefficient (C) is maximized as a plasma heterogeneous velocity estimation value (v); including
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.
According to claim 1,
In the step (b),
The first channel signal (L ₁ ) is band-pass filtered by a first band filter (B ₁ ) that calculates a first filter output signal (L _1B ) by band-filtering the first channel signal (L 1 ) based on a first predetermined Fresnel frequency (f ₁ ). do,
The second channel signal (L ₂ ) is band-filtered by a second band filter (B ₂ ) that performs band-filtering based on a predetermined second Fresnel frequency (f ₂ ) to generate a second filter output signal (L _2B ). to do
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.
According to claim 2,
The band of the first band filter (B ₁ ) is equal to or greater than 0.1 Hz and equal to or less than the first Fresnel frequency (f ₁ );
The band of the second band filter (B ₂ ) is equal to or greater than 0.1 Hz and equal to or less than the second Fresnel frequency (f ₂ )
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.
According to claim 3,
The first Fresnel frequency (f ₁ ) is calculated based on Equation 1 below,
The second Fresnel frequency (f ₂ ) is calculated based on Equation 2 below
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.

According to claim 1,
The frequency of the first channel signal (L ₁ ) is 1575.42 MHz,
The frequency of the second channel signal (L ₂ ) is 1227.60 MHz
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.
According to claim 1,
The correlation coefficient (C) is calculated based on Equation 3 below.

According to claim 1,
In the step (d),
Repeating steps (b) and (c) while increasing the expected plasma speed (v _p ) by 10 m/s
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.
According to claim 7,
The initial value of the expected plasma speed (?? _?? ) is 100 m/s, and the maximum value is 2000 m/s
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.
According to claim 1,
In the step (d),
The correlation coefficient (C) according to the changed expected plasma speed (v _p ) is 0.9 or more, and among the expected plasma speeds (v _p ) in which the phase component ratio is 1.3 or more and 1.9 or less, the correlation coefficient (C) is maximized. To provide the expected plasma speed (v _p ) as a plasma speed estimate (v)
High-latitude ionospheric plasma heterogeneous horizontal direction speed determination method using a single GNSS receiver, characterized by.

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