KR101486329B1 - Apparatus for evaluate ground based augmentation system and method thereof - Google Patents

Abstract

Disclosed are a device and a method for evaluating a ground-based satellite navigation reinforcing system. The device comprises: a residual error calculation unit to calculate a residual error by each satellite altitude according to a performance grade of a ground-based satellite navigation reinforcing system; a first standard deviation calculation unit to calculate a B-value standard deviation by each satellite altitude using B-value data included in a VHF data broadcast signal of the ground-based satellite navigation reinforcing system; a second standard deviation calculation unit to calculate a code minus carrier (CMC) value using an L1 carrier signal and an L2 carrier signal of a GPS and to calculate a CMC standard deviation by each satellite altitude using the CMC value; and a performance evaluation unit to compare the residual error, the B-value standard deviation and the CMC standard deviation by each satellite altitude and to determine whether the ground-based satellite navigation reinforcing system meets required performance.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaluation system for a ground-based satellite navigation reinforcement system,

The present invention relates to an apparatus and method for evaluating a ground-based satellite navigation reinforcement system, and more particularly, to an apparatus and method for evaluating a ground-based satellite navigation reinforcement system capable of improving accuracy performance evaluation of a pseudo range .

Instrumental Landing System (ILS) technology is used for precise approach and landing of aircraft. The instrument landing system is a technology that directs the direction, angle, and distance of the runway to the aircraft by generating directional radio waves at the facilities installed on the ground to approach or land the aircraft.

The instrument landing system includes a localizer that provides directional information on the runway centerline, a glide path that provides landing glide information, and a maker beacon that provides location information.

The localizer is a ground-mounted transmitter and a receiver installed on the aircraft. A pair of radio-frequency modulated 108 ~ 112MHz carrier waves at 90 ~ 150Hz are emitted to the center of the landing ramp. And performs a function of providing a center line.

The glide pass is an instrument to indicate the landing route or its entry route of the aircraft and to provide the safest glide angle information to the approaching aircraft for landing on the runway.

The marker beacon is used to inform the pilot of the passage of a specific point on the airway or in the course of an instrument approach flight, and consists of a marker beacon on the ground and a receiver for the aircraft.

Although the performance of such an instrument landing system is excellent, it requires a large space as well as a huge installation cost because it is a ground fixing system in which a localizer, a glide pass and a marker beacon are installed for each runway on the ground. There is a problem in installation and operation of an instrument landing system in a small airport in a mountainous terrain area.

In order to solve such a problem, a ground based augmentation system (hereinafter referred to as GBAS (Global Positioning System)), which provides a positioning service and an approach service to an aircraft by using a Global Positioning System (GPS) ) Has been developed and operated.

The GBAS ground system periodically checks the function and performance of the equipment through ground tests and flight tests after installation of the equipment. The performance evaluation of the pseudo range domain is one of the evaluation items of the ground test for the GBAS ground system, and periodic performance evaluation is required.

The accuracy of the pseudo range is evaluated using B-value analysis. The B-value analysis method is a method of analyzing and evaluating the actual broadcast B-value value for at least 24 hours in the GBAS terrestrial system. The B-value analysis method can be evaluated through a simple analysis process without complicated data processing, and it is advantageous that it can be evaluated using only the L1 carrier signal of GPS.

However, the B-value analysis method can only evaluate the B-value data broadcasted for at least 24 hours and can only be evaluated through post-processing, and it is difficult to estimate the specific error factors and exact error values There are disadvantages.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and method for evaluating a ground-based satellite navigation reinforcement system capable of improving accuracy performance evaluation of a pseudo range region by making up for shortcomings of a B-value analysis technique.

The apparatus for evaluating a ground-based satellite navigation reinforcement system according to an embodiment of the present invention includes a residual error calculator for calculating a residual error of each satellite altitude angle according to the performance class of the ground-based satellite navigation reinforcement system, A first standard deviation calculation unit for calculating a B-value standard deviation of each satellite altitude angle using the B-value data included in the VHF data broadcast signal, a CMC (Code-Minus) calculation unit using the L1 carrier signal and the L2 carrier signal of GPS, A second standard deviation calculation unit for calculating a CMC standard deviation for each satellite elevation angle by using the CMC value, and a second standard deviation calculation unit for calculating a CMC standard deviation using the CMC standard deviation and the B- And a performance evaluation unit for determining whether the ground-based satellite navigation system augmentation system satisfies the required performance.

And a VDB receiver for receiving the VHF data broadcasting signal of the terrestrial-based satellite navigation system.

And at least one GPS receiver for receiving the L1 carrier signal and the L2 carrier signal of the GPS.

And a data collecting unit receiving the B-value data included in the VHF data broadcasting signal from the VDB receiver and receiving and storing the L1 carrier signal and the L2 carrier signal of the GPS from the at least one GPS receiver, .

The B-value data, the L1 carrier signal and the L2 carrier signal of the GPS are divided into 24 time units, the B-value data divided into 24 time units are transmitted to the first standard deviation calculation unit, And a data distribution unit for transmitting the L1 carrier signal and the L2 carrier signal of the separated GPS to the second standard deviation calculation unit.

The first standard deviation calculation unit may extract a B-value sample from the B-value data divided by the 24-hour unit, classify the B-value sample according to the satellite altitude angle, The B-value standard deviation of each satellite altitude angle can be calculated by calculating the variance value of the B-value at each altitude angle.

Wherein the first standard deviation calculation unit calculates a scale factor of variance for ensuring that the variance value of the B-value has a certain reliability and multiplies the variance value of the B-value by the scale factor to obtain a variance of the B- Value can be calculated.

The second standard deviation calculation unit performs a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information, calculates an ionospheric delay amount using the L1 carrier signal and the L2 carrier signal of the GPS, The CMC value can be calculated by applying the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information.

The second standard deviation calculator may perform a smoothing on a code of an L1 carrier signal of the GPS for each of the at least one GPS receiver, and then perform a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information.

The second standard deviation calculator may remove the ambiguous integer of the L1 carrier signal from the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information.

The second standard deviation calculation unit may extract a CMC sample from the CMC value, classify the CMC sample according to the satellite altitude angle, calculate a variance value of CMC for each satellite altitude angle using the CMC sample, It is possible to calculate the standard CMC standard deviation.

The second standard deviation calculation unit may calculate a variance scale factor for making the variance value of the CMC have a certain reliability and multiply the variance value of the CMC by the scale factor to calculate the variance value of the CMC having a certain reliability have.

The performance class of the ground-based satellite navigation reinforcement system is divided into Letter A, B, and C, and five parameters are determined according to each performance class. The remaining error of each satellite altitude angle is determined by the GPS receiver And the above-mentioned five parameters.

The performance evaluation unit may determine that the terrestrial-based satellite navigation system enhances the first performance if the B-value standard deviation is less than or equal to the satellite altitude residual error.

The performance evaluation unit may determine that the terrestrial-based satellite navigation system reinforcing system satisfies the second required performance when the CMC standard deviation is less than or equal to the satellite altitude residual error.

The performance evaluation unit may determine that the terrestrial-based satellite navigation system augmentation satisfies the final required performance when the terrestrial-based satellite navigation augmentation system satisfies both the first required performance and the second required performance.

A method for evaluating a ground-based satellite navigation reinforcement system according to another embodiment of the present invention includes calculating a residual error of each satellite altitude angle according to a performance class of a ground-based satellite navigation reinforcement system, calculating a VHF data broadcast Calculating a B-value standard deviation for each satellite elevation angle using the B-value data included in the signal, calculating a CMC value using the L1 carrier signal and the L2 carrier signal of the GPS, Calculating a CMC standard deviation for each altitude angle, comparing the remaining altitude difference with the altitude difference, the B-value standard deviation, and the CMC standard deviation to determine whether the terrestrial- .

The performance class of the ground-based satellite navigation reinforcement system is divided into Letter A, B, and C, and five parameters are determined according to each performance class. The remaining error of each satellite altitude angle is determined by the GPS receiver And the above-mentioned five parameters.

The step of calculating the B-value standard deviation of each satellite elevation angle includes: dividing the B-value data by 24 hours; extracting a B-value sample from the B-value data classified by the 24 hour unit; Classifying the B-value samples according to the satellite elevation angle, and calculating a variance value of the B-value for each satellite elevation angle using the B-value sample.

The step of calculating the B-value standard deviation of each satellite altitude angle comprises: calculating a scale factor of variance such that the variance value of the B-value has a certain reliability; and calculating a scale factor of the variance of the B- And calculating a variance value of the B-value having a certain reliability.

The step of calculating the CMC standard deviation of each satellite altitude difference comprises: performing a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information; calculating a difference between the L1 carrier signal and the L2 carrier signal of the GPS, And calculating the CMC value by applying the ionospheric delay amount to a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information.

The step of calculating the CMC standard deviation of each satellite altitude step comprises smoothing the code of the L1 carrier signal of the GPS before performing the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information As shown in FIG.

The step of calculating the CMC standard deviation of each satellite altitude step comprises the step of removing the ambiguous integer of the L1 carrier signal from the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information .

Wherein the step of calculating the CMC standard deviation of each satellite altitude comprises the steps of: extracting CMC samples from the CMC values; classifying the CMC samples according to a satellite altitude angle; And calculating a variance value of the first and second threshold values.

Wherein the step of calculating the CMC standard deviation of each satellite altitude angle comprises: calculating a scale factor of variance for ensuring that the variance value of the CMC has a certain reliability; multiplying the variance value of the CMC by the scale factor, And calculating a variance value of the CMC.

Wherein the step of determining whether the ground-based satellite navigation augmentation system satisfies the required performance comprises: if the B-value standard deviation is less than or equal to the satellite altitude residual error, If the CMC standard deviation is less than or equal to the satellite altitude residual error, determining that the terrestrial-based satellite navigation augmentation system satisfies a second required performance, and determining that the terrestrial- And determining that the terrestrial-based satellite navigation system reinforcement system satisfies the final required performance if the reinforcement system satisfies both the first required performance and the second required performance.

In addition to the B-value analysis method, the accuracy of the performance evaluation can be improved by adding a code-minus-carrier (CMC) analysis technique to evaluate the accuracy of the pseudo range of the GBAS terrestrial system.

In addition, quasi-real-time performance evaluation can be performed using an ordinary performance monitoring algorithm rather than a simple one-time post-processing evaluation. Semi-real-time performance evaluation results can be provided to administrators and controllers who manage and maintain the GBAS ground system, and can be very useful in the management of GBAS ground systems.

1 is a block diagram illustrating an apparatus for evaluating a ground-based satellite navigation reinforcement system according to an embodiment of the present invention.
2 is a flowchart illustrating a process of calculating a B-value standard deviation according to an exemplary embodiment of the present invention.
3 is a flowchart illustrating a process of calculating a CMC standard deviation according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In addition, in the various embodiments, components having the same configuration are represented by the same reference symbols in the first embodiment. In the other embodiments, only components different from those in the first embodiment will be described .

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is a block diagram illustrating an apparatus for evaluating a ground-based satellite navigation reinforcement system according to an embodiment of the present invention.

1, the GBAS evaluation apparatus 100 includes a VDB receiver 101, a GPS receiver 102, a data collection unit 103, a data distribution unit 104, a residual error calculation unit 105, a first standard A deviation calculating unit 106, a second standard deviation calculating unit 107, and a performance evaluating unit 108.

The VDB receiver 101 receives a VHF data broadcast (VDB data) signal of a GBAS terrestrial system. The VDB receiver 101 transmits the B-value data included in the VDB signal to the data collecting unit 103.

The GPS receiver 102 receives dual frequency signals of the L1 carrier of the GPS and the L2 carrier at 2 Hz intervals. The GPS receiver 102 may be a GPS receiver of the reference station of the GBAS terrestrial system. Or the GPS receiver 102 may be provided separately from the GPS receiver of the reference station of the GBAS terrestrial system. The GPS receiver 102 can receive the dual frequency signals of the L1 carrier and the L2 carrier of the GPS from the receiving antenna of the reference station. The GPS receiver 102 transmits the L1 carrier signal and the L2 carrier signal of the GPS to the data collecting unit 103. [ A plurality of GPS receivers 102 may be provided and each of the plurality of GPS receivers 102 may transmit an L1 carrier signal and an L2 carrier signal of GPS to the data collecting unit 103. [

The data collecting unit 103 stores the B-value data received from the VDB receiver 101 and the L1 carrier signal and the L2 carrier signal of the GPS received from the GPS receiver 102 in real time. The data collecting unit 103 may collect pseudo range information and carrier information of the L1 carrier signal and L2 carrier signal of the GPS from each of the plurality of GPS receivers 102. [

The data distribution unit 104 divides the B-value data stored in the data collecting unit 103, the L1 carrier signal of GPS, and the L2 carrier signal by 24 hours (one day). The data distribution unit 104 transmits the B-value data or the L1 carrier signal divided into 24-hour units to the first standard deviation calculation unit 106. [ The data distribution unit 104 transmits the L1 carrier signal and the L2 carrier signal of GPS classified in units of 24 hours to the second standard deviation calculation unit 107. [

)를 산출한다. The residual error calculator 105 calculates a residual error (GAD) according to the ground accuracy designator (GAD) of the GBAS ground system

).

The first standard deviation calculation unit 106 calculates the B-value standard deviation of each satellite altitude angle using the B-value data divided into 24 hours.

The second standard deviation calculator 107 calculates a CMC (code-minus-carrier) value using the L1 carrier signal and the L2 carrier signal of the GPS classified in units of 24 hours, and calculates the satellite altitude The CMC standard deviation of each star is calculated.

)와 B-value 표준 편차 및 CMC 표준 편차를 비교하여 GBAS 지상시스템이 요구 성능을 만족하는지 여부를 판단한다. The performance evaluation unit 108 estimates the residual error of each satellite altitude angle (

) And the B-value standard deviation and the CMC standard deviation to determine whether the GBAS terrestrial system satisfies the required performance.

)를 산출하는 과정에 대하여 설명한다. First, the residual error of satellite altitude according to GAD of the GBAS ground system (

Will be described.

The GPS receiver 102 generates pseudo range information using signals received from GPS satellite signals. The generated pseudo range information includes a satellite clock offset, a troposphere delay, an ionosphere delay, a receiver clock offset, a multipath error, and a receiver thermal noise (thermal noise). The GPS position information calculated using the pseudo range information including the error component has a certain position error according to the size of the error component.

The GBAS ground system estimates the error component (PRC) contained in the GPS signal currently being broadcast on the ground and transmits it to the aircraft. The GPS receiver mounted on the aircraft receives the PRC and corrects the GPS error component to obtain more accurate position information. In order to improve the accuracy of the position information, a more accurate PRC value should be estimated and provided. If a wrong PRC value is provided, errors in the aircraft location information will occur, which can cause serious problems with aircraft safety. Therefore, the GBAS system always estimates and provides the error components included in the PRC information when providing the PRC information.

)가 포함하게 된다.The PRC is a value (PRCsca) obtained by calibrating the GPS satellite clock error and receiver clock error after calibrating the pseudo range between the GPS satellite and the receiver measured by the GPS receiver in the geometric range between the GPS satellite and the GPS receiver Can be calculated. In this case, the PRC has various GPS pseudorange error components such as ionospheric delay error, convective layer delay error, multipath error, and receiver thermal noise, that is, PRC residual error

).

The PRC error component is an error component included in the PRC information provided by the ground station of the GBAS system, which means an error component that is not common between the GPS receiver of the GBAS reference station and the GPS receiver mounted in the aircraft. The PRC error component may include a multipath error, a receiver thermal noise, a receiver tracking error, and the like among the GPS error components mentioned above.

On the other hand, the GBAS terrestrial system can use a smoothing PRC value using code information and carrier information included in the L1 carrier signal of GPS to minimize the influence on the noise component included in the PRC value .

Equation 1 represents the PRC value (PRCcsc) in which the GPS satellite clock error is corrected.

Where R is the geometric distance between the GPS satellite and the GPS receiver, Pcsc is the smoothed PRC value using the code information and carrier information, Δt is the satellite clock error, and c is the speed of light.

Equation (2) represents the smoothed PRC value (Pcsc) using the code information and the carrier information.

Where Pcsc _n is the smoothed PRC value, Pcsc _n-1 is the smoothed PRC value, P is the raw pseudorange correction information, λ is the wavelength of the L1 carrier, φ _n is the carrier, φ _n-1 is the previous carrier, α represents the weight according to the smoothing constant.

Equation (3) represents the PRC value (PRCsca) in which the GPS satellite clock error and the receiver clock error are corrected. This is the pseudorange correction information (PRCsca) generated at the GPS receiver.

Here, i represents the satellite index, j represents the GPS receiver index of the GBAS reference station, and k _i represents the weight according to the GPS satellite altitude angle.

The pseudorange correction information (PRCsca) generated by each GPS receiver of the reference station can be averaged to generate the pseudorange correction information (PRC _TX ) for each GPS satellite generated by the GBAS reference station.

Equation (4) represents pseudorange correction information (PRC _TX ) for each GPS satellite generated by the GBAS reference station and provided to the aircraft.

Here, i is the satellite index, j is the GPS receiver index of the GBAS reference station, M is the total number of GPS receivers of the reference station used to calculate the pseudorange correction information (PRC _TX ), Si is the effective pseudo distance Indicates a reference station GPS receiver set with information.

The B-value information is calculated for each GPS satellite and the average of the PRC information of the corresponding satellite generated by each GPS receiver based on the pseudorange correction information (PRC _TX ) generated in the GBAS reference station for a specific GPS satellite is subtracted Can be calculated.

Equation (5) represents B-value (B (i, j)) information.

Here, i is the satellite index, j is the GPS receiver index of the GBAS reference station, M is the total number of GPS receivers of the reference station used to calculate the pseudorange correction information (PRC _TX ), Si is the effective pseudo distance Indicates a reference station GPS receiver set with information.

)와 거의 일치할 것이다는 가정하에 구해지고, GAD 평가에 활용된다. 이때, PRC 잔여 오차(

)는 GBAS 지상시스템에서 생성된 의사거리보정정보(PRCsca)에 대한 잔여 오차 성분이 된다. Thus, the B-value is not an accurate estimate of the error contained in the pseudorange correction information (PRC _TX ) provided by the GBAS terrestrial system. Instead, the approximate deviation is obtained and the PRC residual error

), And is used for GAD evaluation. At this time, PRC residual error (

) Is the residual error component for the pseudorange correction information (PRCsca) generated in the GBAS terrestrial system.

GAD of the GBAS ground system is divided into Letter A, B and C according to the accuracy of the pseudorange correction information (PRC _TX ) generated by the GBAS reference station for each GPS satellite provided to the aircraft, and five parameters (θ _{0, θ i, a 0,} a 1, a 2) , the value is determined.

Table 1 shows parameters according to GAD.

)가 결정될 수 있다. The residual error of the pseudorange correction information (PRC _TX ) at the satellite altitude provided by the GBAS ground system using the five parameter information determined by GAD

) Can be determined.

)를 나타낸다. Equation (6) is the residual error of the pseudo distance correction information (PRC _TX ) for each satellite altitude

).

Here, M is the number of the GPS receiver in a reference station of the GBAS ground system, i is the GPS satellite index, θ _i represents the elevation angle of the GPS satellite.

)를 산출할 수 있다.As described above, the residual error calculator 105 calculates the residual error (PRC _TX ) of the pseudo range correction information (PRC _TX ) at the satellite altitude in accordance with GAD using Tables 1 and 6

) Can be calculated.

Next, the process of calculating the B-value standard deviation of each satellite altitude angle using the B-value data will be described with reference to FIG.

2 is a flowchart illustrating a process of calculating a B-value standard deviation according to an exemplary embodiment of the present invention.

2, the first standard deviation calculation unit 106 extracts B-value samples from B-value data classified in units of 24 hours, and classifies B-value samples according to satellite altitude angles (S110) . At this time, the first standard deviation calculating unit 106 may extract independent B-value samples at intervals of 200 seconds.

The first standard deviation calculating unit 106 calculates an average and a variance of B-value values for each satellite altitude angle using a B-value sample (S120).

The first standard deviation calculating unit 106 calculates a scale factor of the dispersion so that the calculated B-value variance has a certain reliability (S130). The reliability of the B-value variance can be approximately 95%.

Equation 7 represents the scale factor of the variance.

는 각 위성고도각 별 B-value 샘플의 수,

는

의 자유도를 갖는 x²의 α 백분위수(percentile)를 나타낸다. here,

Is the number of B-value samples at each satellite elevation angle,

The

Represents the alpha percentile of x ² with degrees of freedom.

The first standard deviation calculation unit 106 calculates a B-value variance value with a certain reliability by multiplying the calculated B-value variance value by a scale factor (S140). That is, a B-value variance value having a reliability of approximately 95% can be calculated.

The first standard deviation calculation unit 106 calculates the B-value standard deviation according to the satellite altitude angle of each GPS receiver from the B-value variance value (S150).

Equation (8) is a formula for calculating a B-value standard deviation (RMS _{pr_gnd} ) according to a satellite altitude angle of each GPS receiver from a B-value variance value.

Where M is the number of GPS receivers in the base station of the GBAS terrestrial system, N is the number of B-value samples at each satellite elevation angle, and σ _B is the B-value variance.

Next, the process of calculating the CMC standard deviation of each satellite altitude angle by using the CMC value will be described with reference to FIG.

3 is a flowchart illustrating a process of calculating a CMC standard deviation according to an embodiment of the present invention.

Referring to FIG. 3, the CMC scheme directly calculates the multi-path error, receiver thermal noise, and receiver tracking error generated in each reference station receiver using the dual frequency information of the L1 carrier and the L2 carrier of the GPS, It is a technique to derive the residual error value included. That is, the residual error value included in the actual PRC is calculated, and the result is compared with the reference value according to the GAD to evaluate the performance.

The CMC method is a technique used for evaluating the surrounding environment of a GPS receiver. Since the multipath error, receiver thermal noise, and receiver tracking error are directly estimated, the error included in the GPS signal can be directly derived. This is a way to verify the direct GPS signal quality.

Since the PRC residual error component also includes multipath error, receiver thermal noise, and receiver tracking error, it is possible to derive a direct value when using the CMC technique.

The dual frequency signals of the L1 carrier and the L2 carrier of GPS are received via the plurality of GPS receivers 102 and the pseudo range information of the L1 carrier signal and the L2 carrier signal of GPS from each of the plurality of GPS receivers 102 And carrier information are collected.

The second standard deviation calculation unit 107 performs smoothing on the code P1 of the L1 carrier signal of each GPS receiver 102 (S210). In the CMC method, the estimation accuracy of the CMC value may differ depending on the method of estimating the ionospheric delay amount and the smoothing of the code (pseudo-range) component. In the case of the GBAS system, smoothing is always performed to minimize the noise included in the code component, that is, the error component, and the B-value is also calculated as the PRC using the smoothed pseudorange information. Therefore, smoothing is performed on the code component in using the CMC technique. Smoothing can be performed as shown in Equation (2).

The second standard deviation calculation unit 107 performs a difference between the code P1 information of the L1 carrier signal of the GPS and the L1 carrier information L1 for each GPS receiver 102 at step S220.

Equation (9) represents code (P1) information for the L1 carrier signal of GPS, and Equation (10) represents L1 carrier (L1) information of GPS.

는 GPS 위성과 GPS 수신기 간의 기하학적 거리(geometric range),

는 시계오차(time offset),

은 상대오차(relativistic correction), T는 대류층 지연량, I는 전리층 지연량, K는 하드웨어 바이어스, B는 모호정수,

는 다중경로 오차, MEAS는 수신기 트래킹 오차,

는 수신기 열잡음을 나타낸다.here,

A geometric range between the GPS satellite and the GPS receiver,

Time offset,

T is the amount of delay in the convection layer, I is the amount of ionospheric delay, K is the hardware bias, B is the ambiguity constant,

MEAS is the receiver tracking error,

Represents the receiver thermal noise.

Subtracting Equation (10) from Equation (9), the common error component of the pseudorange and carrier is removed and is expressed as Equation (11).

), 수신기 트래킹 오차(

), 수신기 열잡음 오차(

)는 그 값이 매우 작으므로 소거될 수 있으며, 사이클 슬립(cycle slip)이 발생하지 않는 것으로 가정하면, 수학식 11은 수학식 12와 같이 정리될 수 있다.Multipath Error of Carrier in Subharmonic (11)

), Receiver tracking error (

), Receiver thermal noise error (

) Can be canceled because its value is very small and assuming that no cycle slip occurs, Equation (11) can be summarized as Equation (12).

의 평균을 통해 반송파의 모호정수가 제거될 수 있다. The second standard deviation calculation unit 107 cancels the ambiguity of the carrier wave (S230). That is, in Equation (12), the combination of the GPS satellite and the GPS receiver

The ambiguous integer of the carrier wave can be removed through the average of the carrier frequency.

의 평균을 통해 반송파의 모호정수를 제거하여 정리한 것이다.Equation (13) represents the combination of the GPS satellite and the GPS receiver in Equation (12)

The average of the carrier wave is removed by eliminating the ambiguity.

The second standard deviation calculating section 107 calculates the ionospheric delay amount using the L1 carrier signal and the L2 carrier signal (S240). In the calculation of the ionospheric delay amount, the ionospheric delay amount is calculated using the L1 carrier signal and the L2 carrier signal instead of the GPS code values (P1 and P2) for the purpose of improving estimation accuracy. This is because the estimation accuracy of the ionospheric delay is better when L1 and L2 carrier signals are used than the GPS code value.

Equation (14) represents the ionospheric delay amount calculated using the L1 carrier signal and the L2 carrier signal.

Here, f1 is 1575.42 MHz as the frequency of the L1 carrier signal, and f2 is 1227.6 MHz as the frequency of the L2 carrier signal.

)이다.The second standard deviation calculation unit 107 derives the CMC by substituting Equation (14) into Equation (13) (S250). The CMC includes multipath errors, receiver tracking errors, and receiver thermal noise errors. The CMC including the multipath error, receiver tracking error, receiver thermal noise error, etc., can calculate the residual error of the pseudorange correction information (PRC _TX )

)to be.

Equation (15) represents a CMC including a multipath error, a receiver tracking error, a receiver thermal noise error, and the like.

The second standard deviation calculation unit 107 extracts CMC samples from the derived CMC values and classifies the CMC samples according to the satellite altitude angle (S260). At this time, CMC samples can extract independent CMC samples at intervals of 200 seconds.

The second standard deviation calculation unit 107 calculates an average and variance of the CMC values for each satellite altitude angle using the CMC samples (S270).

The second standard deviation calculation unit 107 calculates a scale factor of variance which makes the calculated CMC variance value have a certain reliability (S280). The reliability of the CMC variance value can be approximately 95%. The scale factor can be calculated as shown in Equation (16).

는 각 위성고도각 별 CMC 샘플의 수,

는

의 자유도를 갖는 x²의 α 백분위수(percentile)를 나타낸다. here,

Is the number of CMC samples at each satellite altitude,

The

Represents the alpha percentile of x ² with degrees of freedom.

The second standard deviation calculation unit 107 calculates the CMC standard deviation according to the satellite altitude angle for each GPS receiver from the CMC variance value (S290). The second standard deviation calculation unit 107 can calculate the CMC standard deviation by multiplying the CMC variance value by the scale factor.

Equation (17) is a formula for calculating the CMC standard deviation (RMS _{pr_gnd} ') according to the satellite altitude angle for each GPS receiver from the CMC variance value.

Where M is the number of GPS receivers in the base station of the GBAS terrestrial system, N is the number of CMC samples at each satellite altitude, and σ _B 'is the CMC variance.

As described above, in applying the CMC scheme, a more accurate CMC value can be extracted by using the smoothed GPS code value and estimating the ionospheric delay amount using the L1 and L2 carrier signals.

Now, a method for evaluating whether or not the performance evaluation unit 108 satisfies the required performance of the GBAS terrestrial system will be described.

)를 전달받고, 제1 표준 편차 산출부(106)에서 각 GPS 수신기 별 위성고도각에 따른 B-value 표준 편차(RMS_{pr_gnd})를 전달받고, 제2 표준 편차 산출부(107)에서 각 GPS 수신기 별 위성고도각에 따른 CMC 표준 편차(RMS_{pr_gnd}')를 전달받는다. The performance evaluating unit 108 calculates the remaining error of the satellite altitude angle according to the GAD in the residual error calculating unit 105

And receives a B-value standard deviation (RMS _{pr_gnd} ) according to a satellite altitude angle of each GPS receiver in a first standard deviation calculation unit 106 and receives a B-value standard deviation (RMS _{pr_gnd} ) The CMC standard deviation (RMS _{pr_gnd} ') corresponding to each satellite altitude angle is received.

)를 비교하여 B-value 표준 편차(RMS_{pr_gnd})가 GAD에 따른 위성 고도각 별 잔여 오차(

)보다 작거나 같은 경우 GBAS 지상시스템이 제1 요구 성능을 만족하는 것으로 판단한다. The performance evaluating unit 108 evaluates the residual error of each altitude of the satellite according to the B-value standard deviation (RMS _{pr_gnd} ) and GAD

), And the B-value standard deviation (RMS _{pr_gnd} ) is _{calculated as the} residual error

), It is judged that the GBAS terrestrial system satisfies the first required performance.

)를 비교하여 CMC 표준 편차(RMS_{pr_gnd}')가 GAD에 따른 위성 고도각 별 잔여 오차(

)보다 작거나 같은 경우 GBAS 지상시스템이 제2 요구 성능을 만족하는 것으로 판단한다. Then, the performance evaluation unit 108 calculates the residual error of each elevation angle of the satellite according to the CMC standard deviation (RMS _{pr_gnd} ') and GAD

), And the CMC standard deviation (RMS _{pr_gnd} ') is _{calculated as the} residual error

), It is judged that the GBAS terrestrial system satisfies the second required performance.

The performance evaluation unit 108 can determine that the GBAS terrestrial system satisfies the final required performance when the GBAS terrestrial system satisfies both the first required performance and the second required performance. That is, the performance evaluation unit 108 can determine that the GBAS terrestrial system is providing suitable pseudorange correction information.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are illustrative and explanatory only and are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention as defined by the appended claims. It is not. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

101: VDB receiver
102: GPS receiver
103: Data collection unit
104: Data distribution unit
105: GPS error component calculating section
106: first standard deviation calculating section
107: second standard deviation calculating section
108: Performance evaluation section

Claims (26)

A residual error calculator for calculating the residual error of the satellite altitude angle according to the performance class of the ground based satellite navigation system;
A first standard deviation calculation unit for calculating a B-value standard deviation of each satellite altitude angle using B-value data included in a VHF data broadcast signal of the ground-based satellite navigation reinforcement system;
A second standard deviation calculation unit for calculating a CMC (Code-Minus-Carrier) value using an L1 carrier signal and an L2 carrier signal of GPS and calculating a CMC standard deviation for each satellite altitude using the CMC value; And
And a performance evaluation unit for determining whether the ground-based satellite navigation system reinforcing system satisfies the required performance by comparing the remaining altitude difference of the satellite altitude with the B-value standard deviation and the CMC standard deviation, Evaluation device. The method according to claim 1,
And a VDB receiver for receiving a VHF data broadcast signal of the ground-based satellite navigation reinforcement system. 3. The method of claim 2,
Further comprising at least one GPS receiver for receiving the L1 carrier signal and the L2 carrier signal of the GPS. The method of claim 3,
Value data included in the VHF data broadcast signal from the VDB receiver, and a data collector for receiving and storing the L1 carrier signal and the L2 carrier signal of the GPS from the at least one GPS receiver, Evaluation system of satellite navigation reinforcement system. 5. The method of claim 4,
The B-value data, the L1 carrier signal and the L2 carrier signal of the GPS are divided into 24 time units, the B-value data divided into 24 time units are transmitted to the first standard deviation calculation unit, And a data distribution unit for transmitting the L1 carrier signal and the L2 carrier signal of the separated GPS to the second standard deviation calculation unit. 6. The method of claim 5,
The first standard deviation calculation unit may extract a B-value sample from the B-value data divided by the 24-hour unit, classify the B-value sample according to the satellite altitude angle, Wherein the B-value standard deviation of each satellite altitude angle is calculated by calculating a variance value of the B-value for each altitude angle. The method according to claim 6,
Wherein the first standard deviation calculation unit calculates a scale factor of variance for ensuring that the variance value of the B-value has a certain reliability and multiplies the variance value of the B-value by the scale factor to obtain a variance of the B- Based evaluation system for a ground-based satellite navigation reinforcement system. 6. The method of claim 5,
The second standard deviation calculation unit performs a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information, calculates an ionospheric delay amount using the L1 carrier signal and the L2 carrier signal of the GPS, Based on the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information to calculate the CMC value. 9. The method of claim 8,
Wherein the second standard deviation calculation unit performs smoothing on the code of the L1 carrier signal of the GPS for each of the at least one GPS receiver and then performs a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information, . 10. The method of claim 9,
And the second standard deviation calculation unit removes the ambiguous integer of the L1 carrier signal from the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information. 9. The method of claim 8,
The second standard deviation calculation unit may extract a CMC sample from the CMC value, classify the CMC sample according to the satellite altitude angle, calculate a variance value of CMC for each satellite altitude angle using the CMC sample, Evaluation system for terrestrial - based satellite navigation reinforcement system that calculates star CMC standard deviation. 12. The method of claim 11,
Wherein the second standard deviation calculation unit calculates a variance scale factor that makes the variance value of the CMC have a certain reliability and multiplies the variance value of the CMC by the scale factor to calculate a variance value of the CMC having a certain reliability Evaluation system for satellite - based navigation reinforcement system. The method according to claim 1,
The performance class of the ground-based satellite navigation reinforcement system is divided into Letter A, B, and C, and five parameters are determined according to each performance class. The remaining error of each satellite altitude angle is determined by the GPS receiver Based on the number and the parameters of the ground-based satellite navigation reinforcement system. The method according to claim 1,
Wherein the performance evaluation unit determines that the terrestrial-based satellite navigation-enhanced system satisfies the first required performance when the B-value standard deviation is less than or equal to the satellite altitude-specific residual error. 15. The method of claim 14,
Wherein the performance evaluation unit determines that the terrestrial-based satellite navigation-enhanced system satisfies the second required performance when the CMC standard deviation is less than or equal to the satellite altitude-specific residual error. 16. The method of claim 15,
Wherein the performance evaluation unit determines that the terrestrial-satellite-navigation-reinforcement system satisfies the final required performance when the terrestrial-based satellite-navigation-reinforcement system satisfies both the first required performance and the second required performance . Calculating a residual error of the satellite altitude angle according to the performance class of the ground-based satellite navigation reinforcement system;
Calculating a B-value standard deviation of each satellite altitude angle by using B-value data included in a VHF data broadcast signal of a ground-based satellite navigation reinforcement system;
Calculating a CMC value using an L1 carrier signal and an L2 carrier signal of GPS, and calculating a CMC standard deviation of each satellite altitude using the CMC value; And
Based satellite navigation system to determine whether or not the ground-based satellite navigation system satisfies the required performance by comparing the satellite altitude residual error with the B-value standard deviation and the CMC standard deviation. Way. 18. The method of claim 17,
The performance class of the ground-based satellite navigation reinforcement system is divided into Letter A, B, and C, and five parameters are determined according to each performance class. The remaining error of each satellite altitude angle is determined by the GPS receiver Based on the number of the satellite-navigation-reinforcement systems and the five parameters. 18. The method of claim 17,
The step of calculating the B-value standard deviation of each satellite altitude angle comprises:
Dividing the B-value data into units of 24 hours;
Extracting a B-value sample from the B-value data divided by the 24-hour unit;
Classifying the B-value samples according to a satellite elevation angle; And
And calculating a variance value of B-value for each satellite altitude angle using the B-value sample. 20. The method of claim 19,
The step of calculating the B-value standard deviation of each satellite altitude angle comprises:
Calculating a scale factor of variance such that the variance value of the B-value has a certain reliability; And
And multiplying the variance value of the B-value by the scale factor to calculate a variance value of the B-value having a certain reliability. 18. The method of claim 17,
Wherein the step of calculating the CMC standard deviation of each satellite altitude angle comprises:
Performing a difference between code information of the L1 carrier signal of the GPS and the L1 carrier information;
Calculating an ionospheric delay amount using the L1 carrier signal and the L2 carrier signal of the GPS; And
And calculating the CMC value by applying the ionospheric delay amount to a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information. 22. The method of claim 21,
Wherein the step of calculating the CMC standard deviation of each satellite altitude angle comprises:
Further comprising smoothing the code of the L1 carrier signal of the GPS before performing the difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information. 22. The method of claim 21,
Wherein the step of calculating the CMC standard deviation of each satellite altitude angle comprises:
Wherein the second standard deviation calculating unit further comprises removing an ambiguous integer of the L1 carrier signal in a difference between the code information of the L1 carrier signal of the GPS and the L1 carrier information. 22. The method of claim 21,
Wherein the step of calculating the CMC standard deviation of each satellite altitude angle comprises:
Extracting a CMC sample from the CMC value;
Classifying the CMC samples according to a satellite elevation angle; And
And calculating a variance value of CMC for each satellite altitude angle using the CMC sample. 25. The method of claim 24,
Wherein the step of calculating the CMC standard deviation of each satellite altitude angle comprises:
Calculating a scale factor of variance such that the variance value of the CMC has a certain reliability; And
And multiplying the variance value of the CMC by the scale factor to calculate a variance value of the CMC having a certain reliability. 18. The method of claim 17,
Wherein the step of determining whether the ground-based satellite navigation system enhances the required performance comprises:
Determining that the terrestrial-satellite-navigation-reinforcement system satisfies the first required performance if the B-value standard deviation is less than or equal to the satellite altitude residual error;
If the CMC standard deviation is less than or equal to the satellite altitude residual error, determining that the terrestrial-based satellite navigation system enhances the second required performance; And
Based satellite navigation reinforcement system satisfies the final required performance when the terrestrial-based satellite navigation reinforcement system satisfies both the first required performance and the second required performance, Evaluation method of the system.

Images