RU2577846C1 - Method of determining integrity of high-precision navigation determinations of consumer and system therefor - Google Patents

Abstract

FIELD: navigation system.

SUBSTANCE: protection levels are calculated on the horizontal and vertical, compared with appropriate emergency limits. Calculation of levels of protection is carried out with due allowance for error position, which can be caused by current measurements, introduction of factors reflecting the confidence range on the horizontal and vertical, for taking into account errors caused by signal during propagation from navigation space vehicles (NSV), and also errors of ephemerical-time data or corrections of satellite hours and orbit, or in case of use of the correcting information transferred from a wide-band functional auxiliaries.

EFFECT: technical result consists in improvement of reliability of high-precision navigation determination and shorter time for alerting the user on the integrity of navigation.

3 cl, 9 dwg

Description

The invention relates to the field of satellite navigation and can be used as an assessment of the accuracy of a high-precision navigation determination.

A known method of intra-system monitoring of navigation signals of each GPS satellite (article “Precise Point Positioning and Integrity Monitoring with GPS and GLONASS”, authors: AlttiJokinen, ShaojunFeng, Carl Milner, Wolfgang Schuster and Washington Ochieng, URL: http://www.rin.org. uk / Uploadedpdfs / ConferenceProceedings / Jokinen% 20paper% 202A-web.pdf (accessed March 28, 2014)), which is carried out as part of solving the task of ephemeris-time support of the system based on non-query measurements of the GPS control segment. All assessments of the quality of functioning of the navigation spacecraft (NSC) are made on the basis of measurements by the P-code, since it is believed that the behavior of the signal parameters in the P and C / A codes is identical. Parameters of the C / A code are monitored only for a brief period of time when the spacecraft ascends in the station visibility sector.

The disadvantage is a long period of time from the moment of determining the malfunction of the spacecraft to the moment of notification to the consumer, since several hours may elapse between the time of the occurrence of the failure of the spacecraft and the moment the flag is set to “not healthy”.

The work “GNSS navigation solution integrity in non-controlled environments” (US 8131463, prior. February 26, 2009) describes an algorithm for assessing the integrity of navigation determination for a single receiver.

The disadvantage of this patent is that the described algorithm does not use corrective information from any functional complement of the global navigation satellite system (GNSS) and does not use the least squares method for determining the location, which leads to a decrease in the accuracy of high-precision navigation determination.

The technical result of the claimed invention is to increase the reliability of high-precision navigation definitions and reduce the time for notifying consumers about a violation of the integrity of navigation.

The technical result of the claimed invention is achieved by the fact that the method for determining the integrity of high-precision navigation definitions of the consumer consists in receiving, using the antenna-feeder device of the receiver, the first radio signal of all visible navigation spacecraft of the global navigation satellite systems containing navigation information, the second radio signal containing corrective navigation information from at least one spacecraft of wide-gap differential systems s, and the third radio signal containing measurements of the primary radio navigation parameters (pseudorange and pseudo-phase) from the reference receiver of the local differential system, then form the measurements of the primary radio navigation parameters (pseudorange and pseudo-phase) in the radio-frequency part of the receiver, using the first signal, transmit the first, to the receiver’s computing device, the second and third radio signals, then in the block of formation of the array of primary measurements of the computing device of the receiver form the second and third aznosti primary navigation parameters using the first and third signals are formed in a block mode of realization relative navigation receiver computing device error covariance matrix

, где R_S - подматрица ошибок невязок вторых разностей измерений псевдодальности; R_δФ - подматрица ошибок невязок вторых разностей измерений приращений псевдофазы; R_Ф - подматрица ошибок невязок вторых разностей измерений псевдофазы,

where R _S is the submatrix of residual errors of the second differences of the pseudorange measurements; R _δФ - submatrix of errors of residuals of the second differences of measurements of increments of the pseudophase; R _f - submatrix of errors of residuals of the second differences of the measurements of the pseudophase,

and projection matrix

,

,

(направляющих косинусов) вектора оцениваемых параметров, с использованием первого, второго и третьего сигналов, определяют в блоке реализации режима относительной навигации вычислительного устройства приемника параметры неоднозначности фазовых измерений на основе полученных вторых и третьих разностей первичных радионавигационных параметров, соответствующих им ковариационной матрицы ошибок и проекционной матрицы, вычисляют в блоке реализации режима относительной навигации вычислительного устройства приемника высокоточное навигационное определение на основе калмановской фильтрации, определяют в блоке определения целостности навигационных определений вычислительного устройства приемника величины ошибок в горизонтальной плоскости и по вертикали, обусловленные текущими измерениями первичных радионавигационных параметровwhere H is the matrix of the second differences of the partial derivatives

(directing cosines) of the vector of the estimated parameters, using the first, second and third signals, determine the ambiguity parameters of the phase measurements on the basis of the obtained second and third differences of the primary radio navigation parameters corresponding to them the covariance error matrix and projection matrix in the relative navigation mode of the receiver computing device , calculate in the block implementation of the relative navigation mode of the computing device of the receiver high-precision navigation The operational determination based on Kalman filtering is used to determine, in the unit for determining the integrity of the navigation definitions of the receiver’s computing device, the horizontal and vertical errors due to current measurements of primary radio navigation parameters

where P ₁₁ , P ₂₂ , P ₃₃ are the elements of the covariance error matrix, determine in the integrity determination unit of the navigation definitions of the receiver computing device horizontal and vertical levels of protection using specified factors reflecting confidence ranges in the plane and in height, reflecting inaccuracies in modeling atmospheric errors and errors caused by multipath, as well as using the accuracy of the formation of the correction of the time-frequency parameters and the orbit of the spacecraft in the wide-gap differential flax system

where A _N is the projection coefficient of errors in the horizontal plane; A _V is the projection coefficient of errors in the vertical plane.

where HPL _VNO is the radius of the circle in the horizontal plane with the center at the point of the real position of the consumer;

VPL _VNO - half the length of the segment in the vertical direction with the center at the point of the real position of the consumer;

K _H - factor reflecting the confidence range in the plane;

K _V - factor reflecting the confidence range in height;

S _bias - accuracy of the formation of corrections of the time-frequency parameters and the orbit of the spacecraft,

In the unit for determining the integrity of the navigation definitions of the computing device of the receiver, the integrity of the high-precision navigation determination of the consumer is evaluated by comparing with the emergency horizontal and vertical limits set by the consumer, then the integrity of the high-precision navigation definitions of the consumer obtained from the computing device of the receiver is reported using the receiver information display device.

The integrity determination system of a high-precision navigation consumer determination consists of all visible navigation spacecraft of the global navigation satellite system, at least one spacecraft of a wide-area differential system, a reference receiver of the local differential system and a receiver, in turn, the receiver consists of the first antenna-feeder device, the input of which is the first input of the receiver, the radio frequency part, the input of which is connected to the output of the first antenna-feeder of the first device, a computing device, the first input of which is connected to the output of the radio frequency part, an information display device, the input of which is connected to the output of the computing device, the receiver also consists of a second antenna-feeder device connected in series, the input of which is the second input of the receiver, and a local receiving device corrective information, the output of the device for receiving corrective information is connected to the second input of the computing device, while all visible navigation The spacecraft of the global navigation satellite system are connected by one-way radio communication with the first input of the receiver and the input of the reference receiver of the local differential system, at least one spacecraft of the wide-gap differential system is connected by one-way radio communication with the first input of the receiver, and the output of the reference receiver of the local differential system is connected by one-way radio communication with the second receiver input.

The computing device of the receiver includes a series-connected block for generating an array of primary measurements, a block for implementing the relative navigation mode and a block for determining the integrity of navigation definitions, respectively, the first and second inputs of a block for forming an array of primary measurements are the first and second inputs of a computing device, respectively, the output of the block for determining the integrity of navigation definitions is the output of a computing device.

The essence and features of the claimed invention are further illustrated by the drawings, which show the following:

in FIG. 1 is a block diagram of a system for determining the integrity of high-precision navigation definitions, where:

1 ... 1 _N - spacecraft wide-gap differential system;

2 ... 2 _N - navigation spacecraft of the global navigation satellite system;

3 - local differential system;

4 - reference receiver of the local differential system;

5 - receiver;

6 - the first antenna feeder device;

7 - second antenna feeder device;

8 - radio frequency part;

9 - a device for receiving local corrective information;

10 - computing device;

11 - device display information;

12 - the first radio signal from the NKA;

13 - the second radio signal from the SC of a wide-gap differential system;

14 - the third radio signal from the reference receiver of the local differential system;

in FIG. 2 is a block diagram of a receiver computing device, where:

10 - computing device;

15 - block forming an array of primary measurements;

16 - block implementation of the relative navigation mode;

17 - unit for determining the integrity of navigation definitions;

in FIG. 3 is a block diagram of an algorithm for determining the integrity of high-precision navigation definitions, where:

18 - the formation of primary measurements;

19 - local differential system;

20 - primary measurements of the reference receiver;

21 - primary measurements of the receiver;

22 - a general array of primary measurements;

23 - relative navigation algorithm;

24 - the formation of the second and third measurement differences;

25 - corrective information wide-gap DS;

26 - the formation of covariance and projection matrices;

27 - determination of the ambiguity parameters of phase measurements;

28 - integrity of navigation definitions;

29 - determination of error values in the horizontal plane and vertically, determined by current measurements;

30 - definition of horizontal (HPL) and vertical (VPL) levels of protection;

31 - integrity determination of a high-precision navigation determination;

32 - collateral integrity;

33 - output of the results of high-precision navigation definitions not provided with a sign of integrity;

34 - the conclusion of reliable results of high-precision navigation definitions;

in FIG. 4 - horizontal, vertical levels of protection and horizontal and vertical position error for the length of the baseline of 20 km;

in FIG. 5 - horizontal, vertical levels of protection and horizontal and vertical position error for the length of the baseline of 35 km;

in FIG. 6 - horizontal, vertical levels of protection and horizontal and vertical position error for the length of the baseline of 45 km;

in FIG. 7 - horizontal, vertical levels of protection and horizontal and vertical position error for the length of the baseline of 20 km;

in FIG. 8 - horizontal, vertical levels of protection and horizontal and vertical position error for the length of the baseline of 35 km;

in FIG. 9 - horizontal, vertical levels of protection and horizontal and vertical position error for the length of the baseline of 45 km when working on the combined constellation NKA GPS / GLONASS.

The solution of the consumer navigation problem based on measurements of the growing volume (Kalman filter) allows us to find an estimate of the consumer position vector taking into account all previously performed measurements, which reduces the influence of anomalous measurement errors on the result of solving the location problem. When describing the model of motion of an object, linearization is used in the vicinity of the current phase vector of the consumer X _k . The transition matrix of the linear model of the object’s motion is F.

A priori estimates of the consumer vector (X) and the covariance matrix of the error in determining the consumer vector (P) are indicated by the superscript "-", and a posteriori estimates are indicated by the index "+".

The procedure for applying the Kalman filter at each measurement step k (k = 0,1,2, ...) has the following form:

• The expected measurement vector is calculated.

(1)

(one)

• The measurement matrix is calculated

(2)

(2)

• The feedback matrix K _{k is} calculated using the equation:

(3)

(3)

• An a posteriori estimation of the consumer phase vector is determined:

(4)

(four)

• The posterior covariance matrix of the error in determining the consumer phase vector is determined:

(5)

(5)

here I is the identity matrix

• An a priori estimate of the covariance matrix is calculated at the next k + 1 step:

(6)

(6)

- ковариационная матрица возмущенийhere

- covariance perturbation matrix

• The consumer phase vector is calculated at the next k + 1 step:

(7)

(7)

In the relative high-precision navigation mode on the GNSS GNA radio signals (2 ₁ ... 2 _N ) received by the reference receiver (4) of the local differential system (3) and the first antenna-feeder device (6) of the receiver (5), in the radio-frequency part (8) of the receiver (5) the formation of measurements of primary radio navigation parameters (pseudorange and pseudo-phase) is carried out (see Fig. 1). The first antenna-feeder device (6) of the receiver (5) receives radio signals from the spacecraft of the wide-gap differential system (1 ₁ ... 1 _N ) with corrections to the satellite clock and the orbit of the GNSS satellite. The reference receiver (4) of the local differential system (3) is located at a point with coordinates known with high accuracy. By means of a second antenna-feeder device (7) and a device for receiving local correction information (9), measurements from the reference receiver (4) of the local differential system (3) are made available in the computing device (10) of the receiver (5). According to measurements from navigation spacecraft (2 ₁ ... 2 _N ), simultaneously observed at the reference receiver (4) and receiver (5), the second and third differences are formed in the computing device (10). The vector of measured parameters can be represented as:

(8)

(8)

where ΔΔS are the second differences of the pseudorange measurements; ΔΔδF - the second difference of the increments of the pseudophase (third difference); ΔΔF - the second difference of the measurements of the pseudophase.

The covariance matrix of measurement errors has the form:

(9)

(9)

where R _S is the submatrix of residual errors of the second differences of the pseudorange measurements; R _δФ - submatrix of errors of residuals of the second differences of measurements of increments of the pseudophase; R _f - submatrix of errors of residuals of the second differences of the measurements of the pseudophase.

In general, the vector of estimated parameters for relative high-precision navigation has the form:

(10)

(10)

where X, Y, Z are the coordinates of the item being determined; N is the ambiguity of the measurements of the pseudophase.

In the claimed method for determining the integrity of high-precision navigation definitions of the consumer, it is proposed to use parameters for assessing the accuracy characteristics of consumer navigation, similar to parameters for wide-area GNSS functional additions (horizontal and vertical level of protection):

• HPL _VNO - the radius of the circle in the horizontal plane with the center at the point of the real position of the consumer.

• VPL _VNO - half the length of the segment in the vertical direction, centered at the point of the real position of the consumer.

The use of these estimates of accuracy characteristics makes it possible to obtain a quantitative assessment of the quality of the navigation definition and display it to the consumer using an information display device (11). Error values for determining the position of the consumer in the horizontal plane and vertically are calculated based on the coefficients of the covariance matrix of errors in determining the position vector:

(11)

(eleven)

(12)

(12)

where P ₁₁ , P ₂₂ , P ₃₃ are the elements of the covariance error matrix (5).

The calculation of HPL _VNO and VPL _{VNO is} carried out according to the following formulas:

(13)

(13)

(14)

(fourteen)

where K _H is the factor reflecting the confidence range in the plane;

K _V - factor reflecting the confidence range in height.

Problems with the calculation of horizontal and vertical levels of protection appear, especially in static cases, when the position estimate in the Kalman filter converges to some very small value. Therefore, it is impossible to use this data to calculate realistic levels of protection. The protection levels calculated by the claimed method only describe the magnitude of the position error that may be caused by current measurements, but these protection levels do not inform the user of complete position errors. The tropospheric, ionospheric errors, as well as the multipath effect present in satellite navigation cannot be modeled or completely corrected. In addition, errors in the ephemeris-time support of navigation spacecraft (NSC), or in satellite clock corrections and orbit corrections, if corrective information is used from a wide-area functional supplement, can have a noise effect on the measurement of navigation parameters.

The above provisions should be taken into account when calculating realistic levels of protection. To ensure the probability of a correct determination of the consumer’s position, ~ 99.9% of the factors reflecting the confidence range in the plane (K _H ) and height (K _V ) are taken equal to 6.

In the claimed method for determining the integrity for high-precision navigation of the consumer, the projection matrix has the form:

(15)

(fifteen)

Then the projection coefficients of errors in the horizontal region (A _H ) and vertically (A _V ) are calculated by the following formulas:

(16)

(16)

(17)

(17)

The horizontal and vertical levels of protection for high-precision navigation mode, taking into account the quality of measurements and the accuracy of the formation of corrections of the time-frequency parameters (CVP) and the orbit of the spacecraft in wide-area functional additions, are calculated by the following formulas:

(18)

(eighteen)

(19)

(19)

where S _bias is the accuracy of the formation of corrections of the FWP and the orbit of the spacecraft.

The accuracy level of the formation of corrections of the FWM and the orbit of the spacecraft in wide-area systems is about 5 cm.

After calculating the horizontal and vertical levels of protection, they are compared with the emergency limit set by the consumer and a decision is made on the integrity of the high-precision navigation definition of the consumer.

An experimental assessment of determining the integrity of navigational definitions was carried out for the mode of relative determinations at different lengths of the baseline and the different composition of the sighted constellation of the NCA. When processing the experimental data, we used an algorithm for the integrated processing of local and wide-area corrective information. As the wide-area corrective information, the corrective information from the wide-area SDKM functional supplement was used: correction of the clock and orbits of the spacecraft, data on the suitability of the spacecraft to perform the target task. The determination of the parameters HPL and VPL was carried out according to the claimed method for determining the integrity of high-precision navigation definitions of the consumer. When calculating HPL and VPL, the following parameter values were used: S _bias = 5 cm; K _H = K _V = 6. Errors in determining the position in the plane (Eh) and height (Ev) were estimated relative to the known a priori coordinates of the point.

The first set of experiments was conducted for a baseline length of about 20 km for the constellation NKA GPS, NKA GLONASS and the combined constellation NKA GLONASS / GPS (figure 4).

The second set of experiments was carried out for a baseline length of about 35 km for the constellation NKA GPS and the combined constellation NKA GLONASS / GPS (figure 5).

The third set of experiments was carried out for a baseline length of about 45 km for the constellation NKA GPS and the combined constellation NKA GLONASS / GPS (Fig.6).

To confirm the repeatability of the results of experimental testing of the developed methodology for determining the integrity of high-precision navigation definitions, a similar set of experiments was carried out on another day. The results of the experimental evaluation for the length of the baseline of 20 km are presented in figure 7, for the length of the baseline of 35 km - in figure 8, for the length of the baseline of 45 km - in figure 9.

The experimental evaluations of the inventive method and system for determining the integrity of high-precision navigation definitions of the consumer show that the calculation of the protection levels in the plane and in height reflects the real picture of the distribution of the error of the navigation definitions of the consumer.

Claims (2)

1. A method for determining the integrity of high-precision navigation definitions of a consumer is that they receive, using the antenna-feeder device of the receiver, the first radio signal of all visible navigation spacecraft of global navigation satellite systems containing navigation information, the second radio signal containing corrective navigation information from at least one space apparatus of a wide-gap differential system, and a third radio signal containing measurements of primary radio navigation parameters (pseudorange and pseudo phase) from the reference receiver of the local differential system, then the primary radio navigation parameters (pseudorange and pseudo phase) are formed in the radio frequency part of the receiver, using the first signal, the first, second and third radio signals are transmitted to the receiver computing device, then in the generating unit the array of primary measurements of the computing device of the receiver form the second and third differences of the primary radio navigation parameters using the first and third signals are formed in a block mode of realization relative navigation receiver computing device error covariance matrix
$$R=\left[\begin{array}{ccc}{R}_s& 0& 0\\ 0& R_{\delta \Phi }& 0\\ 0& 0& R_{\Phi }\end{array}\right]$$

where R _S is the submatrix of residual errors of the second differences of the pseudorange measurements; R _δФ - submatrix of errors of residuals of the second differences of measurements of increments of the pseudophase; R _f - submatrix of errors of residuals of the second differences of the measurements of the pseudophase,
and projection matrix
$$G={\left(H^T{R}_{}^{-\mathrm{one}}H\right)}^{-\mathrm{one}}{H}^T{R}^{-\mathrm{one}}$$

,
where H is the matrix of the second differences of the partial derivatives $$H\left(X\right)=\frac{\partial h\left(X\right)}{\partial X}$$

(guide cosines) of the vector of estimated parameters,
using the first, second, and third signals, the phase measurement ambiguity parameters are determined in the relative navigation mode mode of the receiver computing device based on the obtained second and third differences of the primary radio navigation parameters corresponding to the covariance error matrix and projection matrix, and the relative navigation mode implementation block is calculated receiver computing device high-precision navigation determination based on Kalman filtering, predelyayut block definitions determine the integrity of the navigation receiver error magnitude computing device in the horizontal plane and vertically, due to the current measurements of the primary navigation parameters
$${\sigma }_H=\sqrt{P_{\mathrm{eleven}}+P_{22}}$$

$${\sigma }_V=\sqrt{P_{33}}$$

where P ₁₁ , P ₂₂ , P ₃₃ - elements of the covariance matrix of errors,
the horizontal and vertical levels of protection are determined in the integrity determination unit of the navigation definitions of the receiver computing device using specified factors reflecting confidence ranges in the plane and in height, reflecting inaccuracies in modeling atmospheric errors and errors caused by multipath, and also using the accuracy of the formation of frequency-time correction parameters and orbits of the spacecraft in a wide-gap differential system
$$A_H={\displaystyle \sum _{i=\mathrm{one}}^n\sqrt{G_{\mathrm{one,}i}^2+G_{2i}^2}}$$

$$A_V={\displaystyle \sum _{i=\mathrm{one}}^n\left|G_{3i}^{}\right|}$$

where A _H is the projection coefficient of errors in the horizontal plane; A _V is the projection coefficient of errors in the vertical plane.
$$HP{L}_{\mathrm{AT}N\mathrm{ABOUT}}=K_H\cdot {\sigma }_H+S_{bias}{A}_H$$

$$VP{L}_{\mathrm{AT}N\mathrm{ABOUT}}=K_V\cdot {\sigma }_V+S_{bias}{A}_V$$

where HPL _VNO is the radius of the circle in the horizontal plane with the center at the point of the real position of the consumer;
VPL _VNO - half the length of the segment in the vertical direction with the center at the point of the real position of the consumer;
K _H - factor reflecting the confidence range in the plane;
K _V - factor reflecting the confidence range in height;
S _bias - accuracy of the formation of corrections of the time-frequency parameters and the orbit of the spacecraft,
In the unit for determining the integrity of the navigation definitions of the computing device of the receiver, the integrity of the high-precision navigation determination of the consumer is evaluated by comparing with the emergency horizontal and vertical limits set by the consumer, then the integrity of the high-precision navigation definitions of the consumer obtained from the computing device of the receiver is reported using the receiver information display device.

2. The integrity determination system of a high-precision navigation consumer determination consists of all visible navigation spacecraft of the global navigation satellite system, at least one spacecraft of a wide-gap differential system, a reference receiver of a local differential system and a receiver, in turn, the receiver consists of the first antenna-feeder device, the input of which is the first input of the receiver, the radio frequency part, the input of which is connected to the output of the first antenna feeder a device, a computing device, the first input of which is connected to the output of the radio frequency part, an information display device, the input of which is connected to the output of the computing device, the receiver also consists of a second antenna-feeder device connected in series, the input of which is the second input of the receiver, and a local receiving device correction information, the output of the correction information receiving device is connected to the second input of the computing device, while all visible navigation The spacecraft of the global navigation satellite system are connected by one-way radio communication with the first input of the receiver and the input of the reference receiver of the local differential system, at least one spacecraft of the wide-gap differential system is connected by one-way radio communication with the first input of the receiver, and the output of the reference receiver of the local differential system is connected by one-way radio communication with the second receiver input. 3. The system according to claim 2, in which the computing device of the receiver includes a series-connected unit for forming an array of primary measurements, a unit for implementing the relative navigation mode and a unit for determining the integrity of navigation definitions, respectively, the first and second inputs of the unit for forming an array of primary measurements are first and second the inputs of the computing device, respectively, the output of the integrity determination unit of the navigation definitions is the output of the computing device.

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