CN117055079B

CN117055079B - Method and device for determining total electron content, electronic equipment and readable storage medium

Info

Publication number: CN117055079B
Application number: CN202311320360.5A
Authority: CN
Inventors: 胡鹏; 白伟华; 孟祥广; 孙越强; 杜起飞; 王先毅; 柳聪亮; 蔡跃荣; 李伟; 谭广远; 黄飞雄; 吴汝晗
Original assignee: National Space Science Center of CAS
Current assignee: National Space Science Center of CAS
Priority date: 2023-10-12
Filing date: 2023-10-12
Publication date: 2023-12-22
Anticipated expiration: 2043-10-12
Also published as: CN117055079A

Abstract

The embodiment of the application discloses a method and a device for determining total electron content, electronic equipment and a readable storage medium, wherein the method comprises the following steps: acquiring a pseudo-range observation value and a carrier phase observation value; the pseudo-range observation value and the carrier phase observation value are received by a Global Navigation Satellite System (GNSS) receiver carried on a low orbit earth LEO satellite; establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-side pseudo-range code deviation; solving a target coefficient value of a target coefficient in a target equation and a deviation value of a receiver-end pseudo-range code deviation; and determining the vertical total electronic content VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end.

Description

Method and device for determining total electron content, electronic equipment and readable storage medium

Technical Field

The application belongs to the technical field of information processing, and particularly relates to a method and a device for determining total electron content, electronic equipment and a readable storage medium.

Background

At present, the earth ionosphere is taken as an important component of the space environment of the sun and the earth, and has important influence on the production and the life of human beings. The charged particles in the ionosphere region become abnormally active due to the effects of cosmic or solar activity, and for navigational positioning, the signal delay error generated when the radio wave signal passes through the ionosphere can reach several meters to hundreds of meters, which can severely limit satellite navigational positioning services. The total electron content (Total Electron Content, TEC) is an important index for measuring the ionosphere density in the earth atmosphere, and the index can reflect the thickness of the earth atmosphere ionosphere and also can provide signal channel information of satellite communication. Therefore, determining TEC is significant for satellite navigation.

For convenience of research, TEC on the GNSS signal propagation path can be generally converted into total electron content in the zenith direction of the puncture point, i.e., VTEC, through an ionospheric projection function.

Because a global navigation satellite system (Global Navigation Satellite System, GNSS) monitoring station needs to be established on the solid and stable ground, and most of the earth surface is covered by the ocean, most of the ocean area of the earth cannot be effectively monitored, in addition, with the development of human aerospace technology, more and more artificial satellites are launched into orbit in the future, and a GNSS receiver is carried on a low-orbit satellite, so that LEO precise position information can be acquired, and meanwhile, GNSS electronic total content information can also be acquired; GNSS TEC data can be used as one of important products for spatial weather research due to the advantages of global coverage, high precision, high space-time resolution and the like.

Disclosure of Invention

The embodiment of the application provides a method, a device, equipment and a readable storage medium for determining total electron content, which can solve the problems that the monitoring range of the current ionosphere VTEC is limited and the accuracy is not high.

In a first aspect, embodiments of the present application provide a method for determining total electron content, the method including:

Acquiring a pseudo-range observation value and a carrier phase observation value; the pseudo-range observation value and the carrier phase observation value are received by a Global Navigation Satellite System (GNSS) receiver carried on a low orbit earth LEO satellite;

establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-side pseudo-range code deviation;

solving a target coefficient value of a target coefficient in a target equation and a deviation value of a receiver-end pseudo-range code deviation;

and determining the vertical total electronic content VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end.

In a second aspect, embodiments of the present application provide a total electron content determining apparatus, including:

the acquisition module is used for acquiring a pseudo-range observation value and a carrier phase observation value; the pseudo-range observation value and the carrier phase observation value are received by a GNSS receiver carried on the LEO satellite;

the establishing module is used for establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-end pseudo-range code deviation;

the solving module is used for solving the target coefficient value of the target coefficient in the target equation and the deviation value of the pseudo-range code deviation of the receiver end;

And the determining module is used for determining VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end.

In a third aspect, an embodiment of the present application provides an electronic device, including: a processor and a memory storing computer program instructions; the processor, when executing the computer program instructions, implements the method as in the first aspect or any of the possible implementations of the first aspect.

In a fourth aspect, embodiments of the present application provide a computer readable storage medium having stored thereon computer program instructions which, when executed by a processor, implement a method as in the first aspect or any of the possible implementations of the first aspect.

In the embodiment of the application, a pseudo-range observation value and a carrier phase observation value are obtained; the pseudo-range observation value and the carrier phase observation value are received by a Global Navigation Satellite System (GNSS) receiver carried on a low orbit earth LEO satellite; here, the on-orbit LEO can fly globally, correspondingly, the GNSS receiver carried on the on-orbit LEO also moves globally, so that ionosphere monitoring above the ocean area can be realized, the monitoring range is increased, and the problem that the monitoring range of the current ionosphere VTEC is limited is solved; establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-side pseudo-range code deviation; then, solving a target coefficient value of a target coefficient in a target equation and a deviation value of a receiver-end pseudo-range code deviation, wherein the deviation value of the target coefficient value and the receiver-end pseudo-range code deviation can be rapidly and accurately determined; and finally, determining the vertical total electron content VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the solved high-precision deviation value of the pseudo-range code deviation of the receiver end, thereby realizing real-time high-precision calculation of the VTEC at the LEO end.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described, and it is possible for a person skilled in the art to obtain other drawings according to these drawings without inventive effort.

FIG. 1 is a flow chart of a method for determining total electron content provided in an embodiment of the present application;

FIG. 2 is a flow chart for establishing a target equation provided by an embodiment of the present application;

FIG. 3 is a flow chart for determining weight values provided by an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a total electron content determining device according to an embodiment of the present application;

fig. 5 is a schematic hardware structure of an electronic device according to an embodiment of the present application.

Detailed Description

Features and exemplary embodiments of various aspects of the present application are described in detail below to make the objects, technical solutions and advantages of the present application more apparent, and to further describe the present application in conjunction with the accompanying drawings and the detailed embodiments. It should be understood that the specific embodiments described herein are merely configured to explain the present application and are not configured to limit the present application. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present application by showing examples of the present application.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.

First, technical terms related to embodiments of the present application will be described.

GNSS, also known as global satellite navigation, is an air-based radio navigation positioning system that can provide all-weather 3-dimensional coordinates and velocity and time information to a user at any location on the earth's surface or near-earth space. Which includes one or more satellite constellations and augmentation systems required for supporting a particular job.

Epoch is the beginning of the mark time in calendar. At the position ofAstronomyAre points in time when some astronomical variable is used as reference, e.g. celestial coordinates orCelestial bodyBecause these are subjected toPerturbation ofAnd changes over time.

Ionosphere (Ionosphere), an ionized region of the earth's atmosphere. The whole earth atmosphere above 60 km is in a partially ionized or fully ionized state, and the ionosphere is a partially ionized atmosphere region, which is called a magnetic layer. The entire ionized atmosphere is also known as the ionosphere, and thus the magnetic layer is considered to be part of the ionosphere.

The gas molecules in the troposphere are subjected to various radiation of celestial bodies such as sun and the like to generate strong ionization to form a large number of free electrons and positive ions, the density of the free electrons and the density of the positive ions are equal, the existence of charged particles influences the propagation of electromagnetic waves, the propagation speed is changed, the propagation path is bent, and therefore the product of the signal propagation time At and the light speed C in vacuum is not equal to the geometric distance P from a signal sending point to a signal receiving point, and the deviation is called ionospheric delay or ionospheric refraction error.

The magnitude of the ionospheric delay depends on the total electron content in the signal propagation path and the frequency of the signal, which in turn is related to a number of factors such as time, station location, solar black count, season, altitude from the ground, etc. As with other electromagnetic waves, when the navigation satellite signal passes through the ionosphere, the path of the navigation satellite signal is also curved and the propagation velocity is also changed.

Charged particles are in physics referred to as charged particles. It may be a sub-atomic particle or an ion.

The orbit of low earth satellites (Low Earth Orbit Satellite, LEO) is typically between 400 and 2000 km from the ground.

The global navigation satellite system (Global Navigation Satellite System) is a Global Navigation Satellite System (GNSS), and the GNSS is a unified name for these single satellite navigation positioning systems and enhanced systems such as the beidou system, the GPS, GLONASS, galileo system and the like.

A global satellite positioning system (Global Position System), a system for performing positioning and navigation on a global scale, is called GPS.

Global satellite navigation system (GLObal Navigation Satellite System, GLONASS, GLONASS), also known as gulonass.

GALILEO satellite navigation system (GALILEO) is a global satellite navigation positioning system developed and established by the european union, which was published by the european committee, the european committee being responsible for the european community together with the european empty office in month 2 1999.

The Beidou satellite navigation system (Beidou Navigation Satellite System, BDS) is a global satellite navigation system which is self-developed in China and is also a third mature satellite navigation system after GPS and GLONASS.

The Quasi-zenith satellite system (Quasi-Zenith Satellite System, QZSS) is a satellite augmentation system that accomplishes global positioning system regional functions by time transfer of three satellites.

The broadcast ephemeris is determined and provided by a ground control part of the GNSS system, and is the message information for forecasting the satellite orbit number in a certain time on the radio signal transmitted by the navigation satellite.

Geomagnetic coordinates are astronomical proper nouns. And the magnetic layer coordinate system is various coordinate systems formulated according to the characteristics of the geomagnetic field. The process in the magnetic layer is controlled by the geomagnetic field, and the process can be described relatively simply according to a coordinate system determined by the characteristics of the geomagnetic field.

The hardware delay (Differential Code Biases, DCB) of the receiver is the main error source for extracting ionosphere TEC with GNSS data.

The receiver independent exchange format (Receiver Independent Exchange Format, RINEX) is a standard data format commonly employed in GNSS measurement applications. The format uses text files to store data, and the data recording format is independent of the manufacturer and specific model of the receiver.

The method for determining the total electron content provided by the embodiment of the application can be at least applied to the following application scenes, and the following description is provided.

The earth ionosphere is taken as an important component of the space environment of the sun and the earth, and has important influence on the production and the life of human beings. The charged particles in the ionosphere region become abnormally active due to the effects of cosmic or solar activity, and for navigation positioning, the signal delay error reaches several meters to hundreds of meters when the radio wave signal passes through the ionosphere, which severely limits satellite navigation positioning services.

The ionosphere is monitored by using a GNSS (Global navigation satellite System) method, and a ground monitoring station is often adopted, so that the GNSS monitoring station needs to be established on the ground which is solid and stable, most of the earth surface is covered by ocean, the ground station cannot be uniformly distributed, and the space above most of the ocean area of the earth cannot be effectively monitored.

With the improvement of the four navigation systems of the GNSS and the continuous development of the aerospace technology, the number of LEO satellites in the future is increased continuously, the situation that GNSS receivers are mounted on the GNSS is more, and the ionosphere on the LEO orbit can be detected while the navigation positioning function is provided.

In general, the dual-frequency ionosphere observation value calculated by the GNSS ionosphere TEC includes satellite end hardware code deviation and receiver end hardware code deviation which need to be deducted. The satellite-side code bias has good long-term stability and can be regarded as constant estimation in units of day/week/month, and the receiver-side code bias can have intra-day fluctuation change due to change of surrounding environment (such as temperature), which has adverse effects on ionospheric delay estimation.

Based on the above application scenario, the method for determining the total electron content provided in the embodiment of the present application is described in detail below.

Fig. 1 is a flowchart of a method for determining total electron content according to an embodiment of the present application.

As shown in fig. 1, the total electron content determining method may include steps 110 to 140, and the method is applied to a total electron content determining apparatus, specifically as follows:

step 110, obtaining a pseudo-range observation value and a carrier phase observation value; the pseudo-range observation value and the carrier phase observation value are received by a Global Navigation Satellite System (GNSS) receiver carried on a low orbit earth LEO satellite;

step 120, a target equation is established according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-side pseudo-range code deviation;

step 130, solving a target coefficient value of a target coefficient in a target equation and a deviation value of a receiver-side pseudo-range code deviation;

and 140, determining the vertical total electronic content VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end.

In the method for determining the total electronic content, a pseudo-range observation value and a carrier phase observation value are obtained; the pseudo-range observation value and the carrier phase observation value are received by a Global Navigation Satellite System (GNSS) receiver carried on a low orbit earth LEO satellite; here, the on-orbit LEO can fly globally, and correspondingly, the GNSS receiver carried on the on-orbit LEO also moves globally, so that ionosphere monitoring above the ocean area can be realized, and the monitoring range is increased; establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-side pseudo-range code deviation; then, solving a target coefficient value of a target coefficient in a target equation and a deviation value of a receiver-end pseudo-range code deviation, wherein the deviation value of the target coefficient value and the receiver-end pseudo-range code deviation can be rapidly and accurately determined; and finally, determining the vertical total electron content VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end, thereby realizing real-time high-precision calculation of the VTEC at the LEO end.

The following describes the contents of steps 110 to 140, respectively:

involving step 110.

wherein, the accuracy of the obtained pseudo-range observation value is generally in the meter level; the accuracy of carrier phase observations is typically in the order of millimeters, so that pseudorange observations and carrier phase observations need to be acquired while subsequent calculations are performed.

The carrier phase observation value refers to GNSS observation information, and the GNSS observation information may specifically include: the sampling interval of the GPS system double-frequency observation value, the GLONASS system double-frequency observation value, the GALILEO system double-frequency observation value, the BDS system double-frequency observation value and the QZSS system double-frequency observation value can be high-frequency sampling of 0.1 second, 1 second or 5 seconds.

The corresponding relation between the navigation system and the pseudo-range observation type is shown in table 1:

TABLE 1

In the embodiment of the application, the pseudo-range observation value and the carrier phase observation value which are received by the GNSS receiver carried on the low-orbit earth LEO satellite are obtained, the on-orbit LEO can fly globally, and correspondingly, the GNSS receiver carried on the on-orbit LEO also moves globally, so that ionosphere monitoring above the ocean area can be realized, the monitoring range is improved, and the problem that the monitoring range of the current ionosphere VTEC is limited is solved.

Involving step 120.

establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation is as follows:

wherein,is a weight matrix>For phase smoothing pseudo-range matrix, < >>Is a first matrix, wherein the first matrix comprises parameters to be estimated, < + >>Is a second matrix. The weight matrix and the phase smoothing matrix are determined by pseudo-range observation values and carrier phase observation values. Wherein the raw observations of the pseudorange observations and the carrier phase observations can be expressed as:

wherein: c is the speed of light;

s denotes a navigation satellite, r denotes an LEO satellite.

Representing pseudorange observations;

representing carrier phase observations;

representing the frequency; />Representing the satellite-to-ground distance; />Representing clock differences; />And->Representing a tropospheric projection function and zenith delay amount; />And->Representing ionospheric delay coefficients and delay values; />And->Respectively representing pseudo-range deviation and phase deviation; />And->Representing frequency wavelength and integer ambiguity; />And->Representing pseudorange and phase observation noise.

In one possible embodiment, step 120 includes:

step 210, a first matrix is established according to the target coefficient and the pseudo-range code deviation of the receiver end;

step 220, a second matrix is established according to the carrier phase observation value and a pre-established projection function;

step 230, determining a phase smoothing pseudo-range matrix according to the pseudo-range observation value and the carrier phase observation value;

step 240, establishing a weight matrix according to the carrier phase observation value;

step 250, based on the weight matrix and the phase smoothing pseudo-range matrix, the first matrix and the second matrix, a target equation is established. Next, steps 210 to 250 will be described in order:

step 210, a first matrix is established according to the target coefficient and the receiver-side pseudo-range code bias.

In one possible embodiment, the target coefficients include a first coefficient, a second coefficient, and a third coefficient, step 210 comprising:

establishing a first matrix according to the first coefficient, the second coefficient, the third coefficient and the pseudo-range code deviation of the receiver end; the function relation between the geomagnetic coordinates and the VTEC comprises a first coefficient, a second coefficient and a third coefficient.

，/>

Wherein a is ₀ 、a ₁ And a ₂ A first coefficient, a second coefficient and a third coefficient respectively; here, n satellites in m systems can be observed by presetting a certain epoch, And (3) representing a system, wherein m is a positive integer, n represents the number of navigation satellites, and n is a positive integer.Pseudo-range code bias for the receiver end; />Is the satellite end pseudo-range code deviation.

Here, the receiver-side pseudo-range code bias in the first matrix is an unknown, i.e., a numerical value to be solved.

The geomagnetic coordinates and VTEC have the following functional relationship:

wherein, the geomagnetic coordinate is (M, L), and the function relation between the geomagnetic coordinate and the VTEC comprises a first coefficient, a second coefficient and a third coefficient.

Step 220, a second matrix is established according to the carrier phase observations and the pre-established projection function.

Wherein,is a frequency coefficient;

in one possible embodiment, prior to step 220, the method further comprises:

acquiring the earth radius, the effective height of an ionosphere, the orbit height of a low orbit satellite and the zenith angle;

and establishing a projection function according to the earth radius, the ionosphere effective height, the orbit height of the low orbit satellite and the zenith angle.

Wherein,is a projection function->Is the earth radius>For ionosphere effective height (Ionosphere Effective Height, IEH),>is the orbital altitude of a low-orbit satellite, +.>Is zenith angle.

Step 230, determining a phase smoothed pseudo-range matrix based on the pseudo-range observations and the carrier phase observations.

L=

Wherein s represents navigation satellites, r represents LEO satellites, n represents the number of navigation satellites, and n is a positive integer. smth represents phase smoothing processing.

In one possible embodiment, step 230 includes:

calculating a geometric combination-free observed quantity according to the pseudo-range observed value and the carrier phase observed value;

and determining a phase smoothing pseudo-range matrix according to the geometric combination-free observables. Here, carrier phase observation data of two frequencies in the GNSS signal is used to form a geometric distance-free combination to detect cycle slip, and taking the L1 st and L2 nd frequency points as examples, the L1 nd and L2 nd frequency points are used to identify electromagnetic waves with different wavelengths respectively.

Forming a Geometry-Free (GF) combination observables based on the L1 and L2 frequency point signals;

the calculating the geometric combination-free observed quantity according to the pseudo-range observed value and the carrier phase observed value specifically comprises the following steps:

；

wherein,absolute TEC is calculated based on the pseudo-range observation value; />Is a frequency coefficient, which is determined according to the frequency of L1 and the frequency of L2;

is the absolute TEC calculated based on the carrier phase observations.

Wherein:

wherein,frequency of L1, +.>A frequency of L2;

for the first k consecutive observed pseudoranges and carrier phase GF observations, we can obtain:

Wherein,representing ambiguity;

the determining a phase smoothing pseudo-range matrix according to the geometric combination-free observed quantity specifically may include:

here, the pseudo-range observation value and the carrier phase observation value are smoothed, and the processing result can be regarded as a continuous pseudo-range observation value and carrier phase observation value.

The above formula shows that the carrier phase observations minus the ambiguity result in ionosphere observations equal to the ionosphere model plus the receiver-side pseudorange code bias.

Step 240, building a weight matrix according to the carrier phase observations. Here, according to the carrier phase observation values, comprehensive weighting is performed on all kinds of observation values from three angles of an altitude angle, a signal strength and a smoothing length of a phase smoothing pseudo-range, and a weight matrix is established.

In one possible embodiment, step 240 includes:

acquiring an altitude angle between the LEO satellite and the navigation satellite, and signal strength and smooth length of a signal sent to the LEO satellite by the navigation satellite from carrier observation information;

and establishing a weight matrix according to the altitude angle, the signal intensity and the smooth length.

The carrier observation information comprises an altitude angle between the LEO satellite and the navigation satellite, a signal strength and a smooth length of a signal sent to the LEO satellite by the navigation satellite. The altitude angle, the signal strength and the smooth length can be obtained from the carrier observation information, and the weight matrix is established according to the altitude angle, the signal strength and the smooth length.

Wherein s represents a navigation satellite, r represents an LEO satellite, and n represents the number of navigation satellites;

r1 represents a height angle weight value; r2 represents a signal strength weight value; r3 represents a smoothed length weight value.

The step of establishing the weight matrix according to the altitude angle, the signal strength and the smooth length includes:

step 310, determining an altitude angle weight value according to the altitude angle;

step 320, determining a signal strength weight value according to the signal strength;

step 330, calculating a smoothed length weight value according to the smoothed length;

wherein the weight matrix comprises: altitude angle weight, signal strength weight, and smooth length weight.

The navigation satellite transmits signals, and the signals are attenuated after being reflected by the satellite square plate through the atmosphere and water vapor in the atmosphere; since the signal transmission strength is fixed, the received signal strength reaching the receiver is changed by attenuation, and thus, a signal strength weight corresponding to the signal strength needs to be considered.

Since the measurement of the pseudo-range observation is direct measurement and coarse measurement, the pseudo-range observation can be smoothed by the carrier-phase observation.

The phase smoothed pseudo-range is a data similar to the pseudo-range obtained by smoothing the phase of the satellite signal received by the GPS receiver.

In one possible embodiment, step 310 includes:

determining a height angle weight value as a first weight value in the case that the height angle is smaller than a first threshold value; or,

determining a second weight value according to the altitude angle under the condition that the altitude angle is not smaller than the first threshold value;

determining the altitude angle weight value as a second weight value;

wherein the first weight value is greater than the second weight value.

In ionosphere modeling or monitoring applications based on ground stations, observation data with a height angle below 15 degrees are generally discarded, but the available data amount of LEO single stations is limited, errors possibly caused by low height angles are considered, and appropriate weight reduction processing is performed on the data with the height angle below 15 degrees;

wherein, ELE is the altitude angle;

in the case where the altitude angle is smaller than a first threshold value (e.g., 15 degrees), determining the altitude angle weight value as a first weight value；

In the case that the altitude angle is not smaller than the first threshold value, determining a second weight value according to the altitude angle, namely the second weight value is。

In the case of the first threshold value being 15 degrees, due toAbout 0.65%>Greater than 1, so the first weight value is greater than the second weight value.

In one possible embodiment, step 320 includes:

acquiring the bandwidth of a phase tracking loop of a signal and the carrier phase wavelength;

And determining a signal strength weight value according to the signal strength, the phase tracking loop bandwidth and the carrier phase wavelength.

The signal intensity can directly reflect the receiving quality of the observed value, and can be directly obtained from the RINEX file, the value range is 1-9, the signal intensity is represented from small to large, and the formula of the fixed weight based on the signal intensity weight value is as follows:

wherein,，/>for phase tracking loop bandwidth (HZ), +.>Is the carrier phase wavelength (m).

Thus, the signal strength weight value may be determined from the signal strength, the phase tracking loop bandwidth, and the carrier phase wavelength.

In one possible embodiment, step 330 includes:

under the condition that the smooth length is smaller than the second threshold value, determining a third weight value according to the second threshold value and the smooth length;

determining the smoothed length weight value as a third weight value; or,

determining the height angle weight value as a fourth weight value under the condition that the smooth length is not smaller than a second threshold value;

wherein the third weight value is smaller than the fourth weight value.

Different from the GNSS satellite observed by the ground station, the length of time for the high-dynamic LEO receiver to observe the GNSS satellite is shorter, multipath errors can be eliminated after being averaged by long-time arc segments, and in the real-time resolving process, the weight reduction processing is needed because part of observed data in front of a certain arc segment is greatly influenced by the multipath errors;

Wherein LEN is a smooth length;

under the condition that the smooth length is smaller than the second threshold value, determining a third weight value according to the second threshold value and the smooth length, namely taking the quotient of the second threshold value and the smooth length as the third weight value, and then determining the weight value of the smooth length as the third weight value; or,

and determining the height angle weight value as a fourth weight value in the case that the smooth length is not smaller than the second threshold value, wherein the fourth weight value can be 1.

Wherein, in the case that the smoothing length is smaller than the second threshold, the quotient of the second threshold and the smoothing length is larger than 1, and therefore, the fourth weight value is larger than the third weight value.

Step 250, based on the weight matrix and the phase smoothing pseudo-range matrix, the first matrix and the second matrix, a target equation is established.

Thus, the first matrix and the second matrix may establish the objective equation based on the weight matrix and the phase smoothed pseudo-range matrix respectively constructed as described above.

Involving step 130.

here, single-station ionosphere TEC modeling and pseudo-range code bias estimation can be performed by a sequential least square method, so that a receiver-end pseudo-range code bias value is calculated, and further, the VTEC value of each station star connection of the current epoch is calculated.

In one possible embodiment, the target coefficients include a first coefficient, a second coefficient, and a third coefficient, step 130 comprising:

and solving a first coefficient value of the first coefficient, a second coefficient value of the second coefficient, a third coefficient value of the third coefficient and a deviation value of the receiver-side pseudo-range code deviation based on the weight matrix, the phase smoothing pseudo-range matrix, the first matrix and the second matrix.

Wherein the method comprises the steps ofThe three weight determining modes are respectively corresponding to the height angle weight value, the signal strength weight value and the smooth length weight value.

Wherein the unknowns in the target equation include: target coefficient value of target coefficient and offset value of receiver end pseudo-range code offset.

In the embodiment of the application, the target coefficient value of the target coefficient and the deviation value of the receiver-end pseudo-range code deviation in the target equation established based on the pseudo-range observation value and the carrier phase observation value are solved, and here, the target coefficient value and the deviation value of the receiver-end pseudo-range code deviation can be rapidly and accurately determined, so that the vertical total electronic content VTEC of the ionosphere is determined according to the pseudo-range observation value, the target coefficient value and the solved deviation value of the high-precision receiver-end pseudo-range code deviation, and real-time high-precision calculation of the VTEC at the LEO end is realized.

Involving step 140.

The single-station ionosphere modeling can select a polynomial function model, a trigonometric function model and a low-order spherical harmonic function model, and is shown by taking the polynomial function model as an example:

in one possible embodiment, step 140 includes:

and determining VTEC according to the pseudo-range observation value, the first coefficient value, the second coefficient value, the third coefficient value and the pseudo-range code deviation of the receiver end.

The polynomial function model related to the above is:

wherein, the geomagnetic coordinates are (M, L),and->The first coefficient value, the second coefficient value and the third coefficient value are respectively solved based on the target equation.

In one possible embodiment, step 140 includes:

determining geomagnetic coordinates, satellite altitude and azimuth information according to the pseudo-range observation values and the acquired broadcast ephemeris information;

and determining VTEC according to geomagnetic coordinates, satellite altitude angle, azimuth angle information, target coefficient values and deviation values of pseudo-range code deviation of a receiver end.

Broadcast ephemeris information is textual information that indicates the number of satellite orbits in a future period of time broadcast by the navigation satellite.

In one possible embodiment, the above-mentioned steps for determining geomagnetic coordinates, satellite altitude and azimuth information according to the pseudorange observations and the acquired broadcast ephemeris information include:

performing real-time single point positioning according to the pseudo-range observation value and the broadcast ephemeris information, and calculating to obtain the position information of the receiver;

and calculating geomagnetic coordinates of the ionosphere puncture points, satellite altitude and azimuth information according to the position information of the receiver.

And carrying out real-time single-point positioning on the receiver by using the GNSS pseudo-range observation value and the broadcast ephemeris information to obtain the three-dimensional coordinates of the receiver, and further calculating to obtain geomagnetic coordinates at the ionosphere puncture point.

In one possible embodiment, a historical temperature value of the receiver is obtained, and a historical deviation value of the receiver-side pseudo-range code deviation corresponding to the historical temperature value is obtained;

according to the historical temperature value and the historical deviation value, a polynomial function between the pseudo-range code deviation of the receiver end and the temperature information of the receiver is established, wherein the polynomial function comprises a plurality of parameters;

and estimating a deviation value of the pseudo-range code deviation of the receiver end according to the polynomial function and the acquired temperature value of the receiver.

The temperature information of the GNSS receiver refers to real-time temperature conditions of the satellite-borne receiver, and the sampling interval of the temperature information is consistent with the GNSS observation value.

Meanwhile, considering that the TEC model parameters and the pseudo-range code deviation of the receiver end are estimated in each epoch, in order to prevent the matrix calculation rank from being deficient, a virtual observation equation is added for constraint;

the historical temperature value can be a temperature acquired every second, and can also be a calibration value; and constructing an ionosphere model according to the pseudo-range observation value, and estimating the deviation value of the pseudo-range code deviation of the receiver.

For receiver end code deviation constraint, constructing a corresponding function model by using the acquired receiver temperature information and the DCB value estimated by the previous epoch, and forecasting the DCB value of the current epoch; since the pseudo-range code bias varies with the change of the temperature in the day, the relationship between the pseudo-range code bias at the receiver end and the internal temperature of the receiver is established by a polynomial function:

wherein a is a model parameter, t is a temperature value, and F (t) is a pseudo-range code deviation at a receiver end.

In a possible embodiment, after the step of establishing a polynomial function between the receiver-side pseudo-range code bias and the temperature information of the receiver according to the historical temperature value and the historical bias value, the method may further include:

and adjusting parameters in the polynomial function to enable the pseudo-range code deviation of the receiver end to be within a preset range. For satellite end code deviation parameter constraint, a group of satellite end code deviation values are calculated through accumulation of a daily law equation and used as a tight constraint condition for TEC calculation in the next day; and meanwhile, zero mean constraint is adopted for standard unification of satellite end code deviation of each system.

Because the space environment is stable, the GNSS satellite has stable internal delay;

LEO is in a high-speed flight state, and the pseudo-range code deviation of a receiver end changes more frequently;

the parameters in each polynomial function correspond to a matrix respectively, and the polynomial functions can be adjusted in order that the pseudo-range code deviation of the receiver end is within a preset range. I.e. the parameters in the polynomial function can be adjusted so that the estimated value of the receiver-side pseudo-range code bias in the predetermined range does not exceed the predetermined range.

Therefore, in the embodiment of the application, the real-time TEC calculation can be performed on the satellite, the ionosphere delay change of the upper layer of the satellite orbit can be monitored in real time, and beneficial assistance is brought to researching the boundary height of each layer of the ionosphere, monitoring the solar activity, ionosphere abnormality, ionosphere chromatography and the like.

In summary, in the embodiment of the present application, a pseudo-range observation value and a carrier phase observation value are obtained; the pseudo-range observation value and the carrier phase observation value are received by a Global Navigation Satellite System (GNSS) receiver carried on a low orbit earth LEO satellite; here, the on-orbit LEO can fly globally, and correspondingly, the GNSS receiver carried on the on-orbit LEO also moves globally, so that ionosphere monitoring above the ocean area can be realized, and the monitoring range is increased; establishing a target equation according to the pseudo-range observation value and the carrier phase observation value, wherein the target equation comprises a target coefficient and a receiver-side pseudo-range code deviation; then, solving a target coefficient value of a target coefficient in a target equation and a deviation value of a receiver-end pseudo-range code deviation, wherein the deviation value of the target coefficient value and the receiver-end pseudo-range code deviation can be rapidly and accurately determined; and finally, determining the vertical total electron content VTEC of the ionosphere according to the pseudo-range observation value, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end, thereby realizing real-time high-precision calculation of the VTEC at the LEO end.

Based on the above method for determining the total electron content shown in fig. 1, the embodiment of the present application further provides a data processing apparatus, as shown in fig. 4, the apparatus 400 may include:

an acquisition module 410, configured to acquire a pseudo-range observation value and a carrier phase observation value; the pseudo-range observation value and the carrier phase observation value are received by a GNSS receiver carried on the LEO satellite;

the establishing module 420 is configured to establish a target equation according to the pseudo-range observation value and the carrier phase observation value, where the target equation includes a target coefficient and a receiver-side pseudo-range code bias;

a solving module 430, configured to solve a target coefficient value of a target coefficient in the target equation and a bias value of a receiver-side pseudo-range code bias;

a determining module 440, configured to determine VTEC of the ionosphere according to the pseudorange observation value, the target coefficient value and the deviation value of the receiver-side pseudorange code deviation.

In one possible embodiment, the determining module 440 is specifically configured to:

and determining the VTEC according to the geomagnetic coordinates, the satellite altitude angle, the azimuth angle information, the target coefficient value and the deviation value of the pseudo-range code deviation of the receiver end.

performing real-time single-point positioning according to the pseudo-range observation value and the broadcast ephemeris information, and calculating to obtain the position information of the receiver;

and calculating geomagnetic coordinates, satellite altitude and azimuth information of the ionosphere puncture point according to the position information of the receiver.

In one possible embodiment, the establishing module 420 is specifically configured to:

establishing a first matrix according to the target coefficient and the pseudo-range code deviation of the receiver end;

establishing a second matrix according to the carrier phase observation value and a pre-established projection function;

determining a phase smoothing pseudo-range matrix according to the pseudo-range observation value and the carrier phase observation value;

establishing a weight matrix according to the carrier phase observation value;

and establishing the target equation based on the weight matrix and the phase smoothing pseudo-range matrix, and the first matrix and the second matrix.

before the phase observations and the pre-established projection functions establish the second matrix, the method further comprises:

And establishing the projection function according to the earth radius, the ionosphere effective height, the orbit height of the low orbit satellite and the zenith angle.

and determining the phase smoothing pseudo-range matrix according to the geometric combination-free observed quantity.

establishing the first matrix according to the first coefficient, the second coefficient, the third coefficient and the pseudo-range code deviation of the receiver end; wherein the first coefficient, the second coefficient and the third coefficient are included in a functional relationship between geomagnetic coordinates and the VTEC.

acquiring an altitude angle between the LEO satellite and a navigation satellite, and signal strength and smooth length of a signal sent by the navigation satellite to the LEO satellite from the carrier observation information;

and establishing the weight matrix according to the altitude angle, the signal intensity and the smooth length.

determining a height angle weight value according to the height angle;

determining a signal strength weight value according to the signal strength;

calculating a smooth length weight value according to the smooth length;

wherein the weight matrix comprises: the altitude angle weight value, the signal strength weight value, and the smoothed length weight value.

determining the altitude angle weight value as a first weight value in the case that the altitude angle is smaller than a first threshold value; or,

determining the altitude angle weight value as the second weight value;

wherein the first weight value is greater than the second weight value.

acquiring the phase tracking loop bandwidth and carrier phase wavelength of the signal;

and determining the signal strength weight value according to the signal strength, the phase tracking loop bandwidth and the carrier phase wavelength.

Determining a third weight value according to the second threshold value and the smooth length under the condition that the smooth length is smaller than the second threshold value;

determining the smoothed length weight value as the third weight value; or,

determining the altitude angle weight value as a fourth weight value in the case that the smoothed length is not less than the second threshold value;

wherein the third weight value is smaller than the fourth weight value.

In one possible embodiment, the solving module 430 is specifically configured to:

and solving the deviation value of the first coefficient value, the second coefficient value of the second coefficient, the third coefficient value of the third coefficient and the receiver-side pseudo-range code deviation based on the weight matrix and the phase smoothing pseudo-range matrix, wherein the first matrix and the second matrix.

and determining the VTEC according to the pseudo-range observation value, the first coefficient value, the second coefficient value, the third coefficient value and the receiver-side pseudo-range code deviation.

In one possible embodiment, the apparatus 400 may include:

the estimation module is specifically configured to:

Acquiring a historical temperature value of the receiver and a historical deviation value of the receiver-end pseudo-range code deviation corresponding to the historical temperature value;

establishing a polynomial function between the pseudo-range code deviation of the receiver end and the temperature information of the receiver according to the historical temperature value and the historical deviation value, wherein the polynomial function comprises a plurality of parameters;

and estimating a deviation value of the pseudo-range code deviation of the receiver according to the polynomial function and the acquired temperature value of the receiver.

In one possible embodiment, the apparatus 400 may include:

and the adjusting module is used for adjusting parameters in the polynomial function so as to enable the pseudo-range code deviation of the receiver end to be in a preset range.

Fig. 5 shows a schematic hardware structure of an electronic device according to an embodiment of the present application.

A processor 501 and a memory 502 storing computer program instructions may be included in an electronic device.

In particular, the processor 501 may include a Central Processing Unit (CPU), or an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or may be configured to implement one or more integrated circuits of embodiments of the present application.

Memory 502 may include mass storage for data or instructions. By way of example, and not limitation, memory 502 may comprise a Hard Disk Drive (HDD), floppy Disk Drive, flash memory, optical Disk, magneto-optical Disk, magnetic tape, or universal serial bus (Universal Serial Bus, USB) Drive, or a combination of two or more of the foregoing. Memory 502 may include removable or non-removable (or fixed) media, where appropriate. Memory 502 may be internal or external to the integrated gateway disaster recovery device, where appropriate. In a particular embodiment, the memory 502 is a non-volatile solid state memory. In a particular embodiment, the memory 502 includes Read Only Memory (ROM). The ROM may be mask programmed ROM, programmable ROM (PROM), erasable PROM (EPROM), electrically Erasable PROM (EEPROM), electrically rewritable ROM (EAROM), or flash memory, or a combination of two or more of these, where appropriate.

The processor 501 reads and executes the computer program instructions stored in the memory 502 to implement any one of the total electron content determination methods in the embodiments shown in the figures.

In one example, the electronic device may also include a communication interface 503 and a bus 510. As shown in fig. 5, the processor 501, the memory 502, and the communication interface 503 are connected to each other by a bus 510 and perform communication with each other.

The communication interface 503 is mainly used to implement communication between each module, apparatus, unit and/or device in the embodiments of the present application.

Bus 510 includes hardware, software, or both that couple components of the electronic device to one another. By way of example, and not limitation, the buses may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an infiniband interconnect, a Low Pin Count (LPC) bus, a memory bus, a micro channel architecture (MCa) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a video electronics standards association local (VLB) bus, or other suitable bus, or a combination of two or more of the above. Bus 510 may include one or more buses, where appropriate. Although embodiments of the present application describe and illustrate a particular bus, the present application contemplates any suitable bus or interconnect.

The electronic device may perform the method for determining the total electron content in the embodiments of the present application, thereby implementing the method for determining the total electron content described in connection with fig. 1 to 3.

In addition, in combination with the method for determining the total electron content in the above embodiments, embodiments of the present application may be implemented by providing a computer-readable storage medium. The computer readable storage medium has stored thereon computer program instructions; the computer program instructions, when executed by the processor, implement the total electron content determination method of fig. 1-3.

It should be clear that the present application is not limited to the particular arrangements and processes described above and illustrated in the drawings. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method processes of the present application are not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps, after appreciating the spirit of the present application.

The functional blocks shown in the above-described structural block diagrams may be implemented in hardware, software, firmware, or a combination thereof. When implemented in hardware, it may be, for example, an electronic circuit, an Application Specific Integrated Circuit (ASIC), suitable firmware, a plug-in, a function card, or the like. When implemented in software, the elements of the present application are the programs or code segments used to perform the required tasks. The program or code segments may be stored in a machine readable medium or transmitted over transmission media or communication links by a data signal carried in a carrier wave. A "machine-readable medium" may include any medium that can store or transfer information. Examples of machine-readable media include electronic circuitry, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio Frequency (RF) links, and the like. The code segments may be downloaded via computer networks such as the internet, intranets, etc.

It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above-described steps, that is, the steps may be performed in the order mentioned in the embodiments, may be different from the order in the embodiments, or several steps may be performed simultaneously.

In the foregoing, only the specific embodiments of the present application are described, and it will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the systems, modules and units described above may refer to the corresponding processes in the foregoing method embodiments, which are not repeated herein. It should be understood that the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the present application, which are intended to be included in the scope of the present application.

Claims

1. A method for determining total electron content, the method comprising:

solving a target coefficient value of the target coefficient in the target equation and a deviation value of the receiver-side pseudo-range code deviation;

2. The method of claim 1, wherein said determining the vertical total electron content VTEC of the ionosphere based on said pseudorange observations, said target coefficient values and bias values of said receiver-side pseudorange code bias comprises:

and determining the VTEC according to the geomagnetic coordinates, the satellite altitude angle, the azimuth angle information, the target coefficient value and the deviation value of the receiver-side pseudo-range code deviation.

3. The method of claim 2, wherein said determining geomagnetic coordinates, satellite altitude and azimuth information from said pseudorange observations and acquired broadcast ephemeris information comprises:

and calculating geomagnetic coordinates of the ionosphere puncture points, satellite altitude angles and azimuth angle information according to the position information of the receiver.

4. The method of claim 1, wherein said establishing a target equation from said pseudorange observations and carrier phase observations comprises:

establishing a weight matrix according to the carrier phase observation value;

5. The method of claim 4, wherein prior to said establishing a second matrix from said carrier phase observations and a pre-established projection function, the method further comprises:

6. A method as defined in claim 4, wherein said determining a phase smoothed pseudorange matrix from said pseudorange observations and said carrier phase observations comprises:

7. The method of claim 4, wherein the target coefficients comprise a first coefficient, a second coefficient, and a third coefficient, and wherein the establishing a first matrix based on the target coefficients and the receiver-side pseudorange code bias comprises:

8. The method of claim 4, wherein said establishing a weight matrix from said carrier phase observations comprises:

9. The method of claim 8, wherein the establishing the weight matrix based on the altitude angle, the signal strength, and the smoothed length comprises:

determining a height angle weight value according to the height angle;

determining a signal strength weight value according to the signal strength;

calculating a smooth length weight value according to the smooth length;

10. The method of claim 9, wherein said determining a altitude angle weight value from said altitude angle comprises:

determining the altitude angle weight value as the second weight value;

wherein the first weight value is greater than the second weight value.

11. The method of claim 9, wherein said determining a signal strength weight value from said signal strength comprises:

12. The method of claim 9, wherein said calculating a smoothed length weight value from said smoothed length comprises:

determining the smoothed length weight value as the third weight value; or,

wherein the third weight value is smaller than the fourth weight value.

13. The method of claim 7, wherein the target coefficients comprise a first coefficient, a second coefficient, and a third coefficient, and wherein solving for target coefficient values and receiver-side pseudorange code deviations for the target coefficients in the target equation comprises:

14. The method of claim 13, wherein said determining the vertical total electron content VTEC of the ionosphere based on said pseudorange observations, said target coefficient values, and bias values of said receiver-side pseudorange code bias comprises:

15. The method according to claim 1, wherein the method further comprises:

16. The method of claim 15, after said establishing a polynomial function between said receiver-side pseudorange code bias and said temperature information of said receiver based on said historical temperature values and said historical bias values, said method further comprising:

and adjusting parameters in the polynomial function so as to enable the pseudo-range code deviation of the receiver end to be within a preset range.

17. A total electron content determining device, the device comprising:

The solving module is used for solving a target coefficient value of the target coefficient in the target equation and a deviation value of the receiver-side pseudo-range code deviation;

18. The apparatus according to claim 17, wherein the establishing module is specifically configured to:

establishing a weight matrix according to the carrier phase observation value;

19. An electronic device, the device comprising: a processor and a memory storing computer program instructions; the processor, when executing the computer program instructions, implements the total electron content determination method as claimed in any one of claims 1-16.

20. A readable storage medium, characterized in that the readable storage medium has stored thereon computer program instructions, which when executed by a processor, implement the total electron content determination method according to any of claims 1-16.