CN112526618B - Ionospheric tomography measuring instrument based on multi-band multi-constellation satellite signals and observation method thereof - Google Patents

Abstract

The invention discloses an ionosphere tomography measuring instrument based on multi-band multi-constellation satellite signals and an observation method thereof. According to the ionosphere tomography measuring instrument based on the multi-band multi-constellation satellite signals, disclosed by the invention, the measurement of the medium-high orbit satellite signals and the low orbit satellite signals are combined, so that the measurement accuracy of the ionosphere electron density is improved; multiple GNSS satellite navigation systems are combined, satellite observation paths are expanded, and more accurate TEC distribution is given out; the multi-band satellite signals are combined, and comprehensive measurement of multi-band wide-scale ionosphere scintillation and inhomogeneous body parameters is realized.

Description

Ionospheric tomography measuring instrument based on multi-band multi-constellation satellite signals and observation method thereof

Technical Field

The invention belongs to the technical field of ionosphere detection, and particularly relates to an ionosphere tomography measuring instrument based on multi-band multi-constellation satellite signals and an observation method thereof.

Background

The accurate detection of ionosphere changes has important supporting effects on optimizing a plurality of radio information systems such as short wave communication, satellite navigation, measurement and control monitoring and the like. Among the characteristic parameters of the ionosphere, the ionosphere electron density is the most critical detection parameter, and detecting and acquiring the space-time variation of the ionosphere electron density has important theoretical significance and application value in the fields of satellite communication, satellite navigation, space weather and the like. The traditional ionosphere electron density detection mainly depends on active detection means such as a digital altimeter and an oblique detector, and has the defects of electromagnetic environment pollution, large occupied area, high maintenance cost and the like.

With the development of satellite technology, satellite signal based technology has become an important development direction in the field of ionosphere detection technology. In order to obtain a fine structure of the spatial-temporal distribution of the electron density of the ionosphere, austen et al, university of Ill. In 1986, revolutionarily proposed the concept of ionosphere tomography (Computerized Tomography, CT), i.e. the realization of a fast and accurate imaging of the electron density of the ionosphere by means of satellite transmitted beacon signals in combination with terrestrial station chain reception, which technology has now gained widespread attention and application internationally.

Currently, passive detection of the ionosphere relies mainly on GPS satellite signals to achieve a large-scale, continuous measurement of the ionosphere. However, because the GPS satellite orbit is high and the GPS satellite orbit passes the top of the GPS satellite for more than three to four hours at a time, the static assumption condition of the ionosphere is not satisfied, and the high-precision chromatographic measurement of the electronic density of the ionosphere is difficult to realize; and the GPS satellite is only an L-band signal, the measurement frequency band is relatively high, and the method has larger limitation in measuring ionosphere scintillation and non-uniformity.

Along with the in-orbit operation of a large number of navigation satellites, communication satellites and scientific detection satellites, the passive measurement of the ionosphere by satellite signals becomes a trend and tide, and the equipment for realizing the large-scale, long-term continuous and high-precision ionosphere measurement by combining the satellite measurement with different heights and different frequency bands becomes the direction of future development.

Disclosure of Invention

The invention aims to provide an ionospheric tomography measuring instrument capable of simultaneously receiving low-orbit LEO satellites and high-orbit MEO, GEO satellites VHF, UHF and L frequency band satellite signals in multiple constellations and an observation method thereof.

The invention adopts the following technical scheme:

in an ionospheric tomography measurement instrument based on a multi-band multi-constellation satellite signal, the improvement comprising: the system comprises a data comprehensive processing unit, a low-orbit satellite beacon ionosphere measuring component, a GNSS satellite signal ionosphere measuring component, a data storage unit, a power supply unit and a data display control unit, wherein the low-orbit satellite beacon ionosphere measuring component is electrically connected with the data comprehensive processing unit;

the data comprehensive processing unit comprises a three-dimensional time-varying multi-scale ionosphere electron density tomography unit and a multi-band wide-scale ionosphere inhomogeneous structure parameter inversion unit;

the low-orbit satellite beacon ionosphere measuring component comprises a VHF, UHF, L multi-band antenna, a low-orbit satellite signal radio frequency module, a low-orbit satellite signal intermediate frequency processing module and a low-orbit satellite ionosphere data processing module;

the GNSS satellite signal ionosphere measurement component comprises a GNSS antenna, a GNSS satellite signal receiving measurement module, a TEC and a flicker index calculation module.

Further, the three-dimensional time-varying multi-scale ionosphere electron density tomography unit comprises a low-orbit satellite beacon, a middle-high orbit GNSS data fusion processing module, a three-dimensional time-varying tomography mapping matrix construction module and a multi-resolution ionosphere tomography inversion module;

the low-orbit satellite beacon and middle-high-orbit GNSS data fusion processing module is used for carrying out fusion processing on data obtained by receiving the low-orbit satellite beacon and the middle-high-orbit GNSS satellite signals, integrating and converting TEC into a matrix form, and fusing the observed data of the middle-high-orbit GNSS satellite and the low-orbit satellite beacon into a projection matrix based on a discretization characterization method of the total electronic content of an ionosphere, so as to obtain local high-density projection data;

the three-dimensional time-varying tomography mapping matrix construction module adopts a transformation technology, selects a proper mapping matrix and discretizes the space-time distribution of the ionosphere electron density; the construction method of the mapping matrix is that the orthogonal basis functions formed by classical or physical models are converted into linear combination of multidimensional basis functions by constructing the mapping matrix in the horizontal and vertical directions; or a pixel basis function is adopted;

the multi-resolution ionosphere tomographic inversion module flexibly gives the scale of the tomographic structure according to the quantity and distribution of available projection data in an inversion area, the projection data density is high, then the ionosphere structure with small and medium scale is reconstructed, the ionosphere electron density distribution map with large scale is reconstructed by inversion with sparse data, the scale of the inversion result of the first stage is maximum, the inversion result of the second stage is performed again on the result of the first stage, and the steps are analogized in a step-by-step manner, so that the scale of the ionosphere tomographic structure is gradually decreased, and the image is gradually refined;

the multi-band wide-scale ionosphere non-uniform body structure parameter inversion unit comprises a large-scale ionosphere disturbance reconstruction module based on space-time variation of ionosphere characteristic parameters and a small-scale ionosphere non-uniform body parameter inversion module based on scintillation signal power spectrum analysis;

the large-scale ionosphere disturbance reconstruction module based on the space-time variation of the ionosphere characteristic parameters carries out differential calculation on time and space based on the ionosphere TEC and scintillation index data extracted by the measuring instrument to obtain horizontal gradient ionosphere disturbance parameters of the ionosphere ROTI and the TEC, and the evolution of the ionosphere large-scale disturbance structural strength and the spatial distribution along with the time is reproduced; the module simultaneously utilizes the cooperative observation of a ground receiving station chain and a network to extract ionosphere large-scale traveling disturbance LS-TID information, wherein the information comprises amplitude, period and horizontal phase velocity parameters;

the small-scale ionosphere non-uniform body parameter inversion module based on scintillation signal power spectrum analysis obtains ionosphere non-uniform body spectrum index, drift speed and non-uniform body intensity parameters by inversion based on ionosphere scintillation observation information of different satellites at the same moment and combining parameter information of an ionosphere non-uniform body experience model.

Furthermore, the VHF, UHF, L multiband antenna adopts an active orthogonal feed orthogonal dipole antenna, the polarization mode is circular polarization, the antenna comprises a filter, a combiner, a low-noise amplifier and a power supply module, and radio frequency signals received by the antenna array enter the combiner after passing through the filters and the low-noise amplifier of each frequency band and are output after being combined by the combiner.

Further, the low-orbit satellite signal radio frequency module comprises a receiving channel, a frequency synthesis part and a control circuit, and converts the four-frequency-band signal output by the antenna into an intermediate frequency signal of 1.7MHz, wherein the receiving channel finishes down-conversion; the frequency synthesis part provides local oscillation signals for all channels and provides reference clock signals for the intermediate frequency processing module; the control circuit is responsible for communicating with the intermediate frequency processing module, receiving the control command sent by the intermediate frequency processing module, and then completing various control functions.

Further, the low-orbit satellite signal intermediate frequency processing module comprises a signal conditioning circuit and an FPGA chip, the intermediate frequency processing module firstly conditions intermediate frequency signals of three channels, then converts the intermediate frequency signals into numerical signals through an AD chip, inputs the numerical intermediate frequency signals into the FPGA chip for filtering and synchronization, and then outputs the numerical intermediate frequency signals to the DSP chip for further completing signal capturing processing, and meanwhile, the intermediate frequency processing module controls the radio frequency module to complete various control functions.

Further, the low-orbit satellite ionosphere data processing module outputs the signal intensity and the phase of the three frequency band signals in real time by acquiring the sampling rate of 50Hz of the intermediate frequency processing module, so as to acquire the total electronic content TEC of the ionosphere of the low-orbit satellite beacon.

Further, the GNSS antenna adopts a choke coil antenna; the GNSS satellite signal receiving and measuring module comprises a radio frequency processing unit, a data acquisition unit, a baseband information processing unit, a navigation data resolving and observing quantity extracting unit and a data interface unit, and is used for receiving the double-frequency signals of the Beidou, GPS and GLONASS satellite systems, carrying out tracking measurement on the double-frequency signals and extracting I, Q information and carrier phase original information; the TEC and scintillation index calculation module adopts a hardware processing platform taking ARM as a core, the module obtains the ionosphere TEC of GNSS signals through observation data preprocessing, puncture point calculation, ionosphere observation equation construction, hardware delay calculation, residual error statistics and coarse difference detection and ionosphere TEC calculation, and the module receives statistics and filtering processing is carried out on signal amplitude information and carrier phase information obtained by the GNSS satellite signal intermediate frequency module, so that scintillation index calculation is completed.

Furthermore, the data storage unit adopts a standard storage hard disk, and the capacity of the hard disk is not less than 1TB; the power supply unit adopts 220V commercial power, and a power supply conversion circuit is internally arranged in the power supply unit to convert alternating current into 12V, 5V and 3.3V direct current voltages for meeting the power supply requirements of each module; the data display and control unit adopts an industrial computer.

Furthermore, the low-orbit satellite beacon ionosphere measuring component, the GNSS satellite signal ionosphere measuring component, the data comprehensive processing unit, the data storage unit, the power supply unit and the data display and control unit are integrated on a universal bus hardware platform and adopt a unified interface design, and control signals and data information are transmitted by using CPCI buses.

An observation method using the ionospheric tomography measuring instrument based on the multi-band multi-constellation satellite signal, the improvement comprising the steps of:

in a selected observation area, the observation of an regional ionosphere TEC, electron density and non-uniformity is realized by a networking observation method of at least 4 measuring instruments, wherein the mutual interval between the measuring instruments is not more than 500 km, the mutual communication capability is realized, the measuring instruments are powered by single-phase mains supply, and data communication is realized through the Internet or private network;

step 2, arranging measuring instruments in a designated observation field, wherein no receiver near the field receives interference signals in a frequency band, and grounding each measuring instrument and installing on-line UPS and power protection equipment;

step 3, erecting an observation antenna outside the field, simultaneously installing a measuring instrument and an industrial personal computer in the same cabinet, transmitting measurement data to the industrial personal computer by the measuring instrument through a network cable, and exchanging working instructions, time systems, working states and observation data with the industrial personal computer;

step 4, after the measuring instrument is installed and operated, the measuring data and the working state are automatically transmitted to the industrial personal computer, and the remote data center can monitor the equipment state and receive the data for processing and release;

step 5, the measuring instrument receives the GNSS satellite and the low orbit satellite beacon data, performs non-uniform inversion, and performs data transmission, information and result display to the central end through the Internet or private network;

and 6, the data center receives data transmitted by each measuring instrument through the Internet or a private network, performs multi-station data fusion processing and three-dimensional time-varying ionosphere tomography, is provided with a database, and is responsible for warehousing, storing and managing the data transmitted by the measuring instrument and the data processed by the data center.

The beneficial effects of the invention are as follows:

the ionosphere tomography measuring instrument based on the multi-band multi-constellation satellite signals combines the advantages of measuring TEC and electron density of a middle-high orbit GNSS satellite and a low-orbit ionosphere beacon satellite, and simultaneously adds a Beidou satellite navigation system, a Russian GLONASS satellite navigation system and a European GALILEO satellite navigation system of China on the basis of measuring only GPS satellite signals of the prior art, thereby greatly expanding the observation path of the middle-high orbit satellite (more than 20 visible satellites in any place of the world); meanwhile, on the basis of the GNSS L frequency band, low-orbit LEO satellite ionosphere VHF, UHF and L beacon frequency bands are added. The large-scale, continuous and high-precision measurement of the TEC and the electron density distribution, the flicker and the uneven body structure is realized by carrying out fusion processing on satellite signal measurement information of different orbits, different paths and different frequency bands.

The ionosphere tomography measuring instrument based on the multi-band multi-constellation satellite signals disclosed by the invention performs inversion imaging of electron density by using the medium-high orbit satellite beacons to obtain continuous ionosphere electron density distribution with a large range; meanwhile, the low-orbit ionosphere beacon signal is used for acquiring short-time and high-precision ionosphere electron density to update the low-orbit ionosphere beacon signal at fixed time, so that the defect of the existing satellite signal ionosphere detection instrument is effectively overcome, and the detection precision of the ionosphere electron density is effectively improved; meanwhile, the invention combines the multi-band satellite signals, thereby simultaneously acquiring ionosphere flicker and inhomogeneous information of VHF frequency band, UHF frequency band, L frequency band and other wide frequency bands, and greatly improving the detection capability of ionosphere disturbance.

According to the ionosphere tomography measuring instrument based on the multi-band multi-constellation satellite signals, disclosed by the invention, the measurement of the medium-high orbit satellite signals and the low orbit satellite signals are combined, so that the measurement accuracy of the ionosphere electron density is improved; multiple GNSS satellite navigation systems are combined, satellite observation paths are expanded, and more accurate TEC distribution is given out; the multi-band satellite signals are combined, and comprehensive measurement of multi-band wide-scale ionosphere scintillation and inhomogeneous body parameters is realized.

The observation method disclosed by the invention has the advantages of passive detection, automatic operation, low power consumption, strong environmental adaptability and the like, and is particularly suitable for application with higher reliability requirements.

Drawings

FIG. 1 is a block diagram of the measuring instrument disclosed in embodiment 1 of the present invention;

FIG. 2 is a flow chart of the operation of three-dimensional time-varying multiscale ionosphere electron density tomography software in the measuring instrument disclosed in example 1 of the present invention;

FIG. 3 is a flow chart of the operation of the parameter inversion software for the ionosphere non-uniform volume structure with multiple frequency bands and wide dimensions in the measuring instrument disclosed in the embodiment 1 of the present invention;

fig. 4 is a block diagram of a VHF, UHF, L multiband antenna according to an embodiment 1 of the present invention;

FIG. 5 is a block diagram of a RF module for low-orbit satellite signals in the measuring instrument according to the embodiment 1 of the present invention;

FIG. 6 is a block diagram showing the hardware components of the intermediate frequency processing module of the low-orbit satellite signal in the measuring instrument disclosed in the embodiment 1 of the present invention;

fig. 7 is a block diagram of a GNSS satellite signal reception measurement module in the measurement apparatus according to embodiment 1 of the present invention.

Description of the embodiments

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

An embodiment 1, as shown in fig. 1, discloses an ionospheric tomography measuring instrument based on multi-band multi-constellation satellite signals, which comprises a data comprehensive processing unit, a low-orbit satellite beacon ionosphere measuring component, a GNSS satellite signal ionosphere measuring component, a data storage unit, a power supply unit and a data display control unit, wherein the low-orbit satellite beacon ionosphere measuring component is electrically connected with the data comprehensive processing unit;

the data comprehensive processing unit comprises three-dimensional time-varying multi-scale ionosphere electron density tomography software and multi-band wide-scale ionosphere inhomogeneous structure parameter inversion software;

as shown in fig. 2, the three-dimensional time-varying multiscale ionosphere electron density tomography software comprises a low-orbit satellite beacon and middle-high orbit GNSS data fusion processing module, a three-dimensional time-varying tomography mapping matrix construction module and a multi-resolution ionosphere tomographic inversion module;

the low-orbit satellite beacon and the middle-high-orbit GNSS data fusion processing module is used for carrying out fusion processing on data obtained by receiving the low-orbit satellite beacon and the middle-high-orbit GNSS satellite signals, integrating and converting TEC into a matrix form, and based on a discretization characterization method of total electronic content of an ionosphere, fusing observed data of the middle-high-orbit GNSS satellite and the low-orbit satellite beacon to generate a projection matrix, so that mutual complementation of data is realized, local high-density projection data is obtained, system errors caused by inconsistent measurement geometric distribution among measurement means are eliminated, and a reliable data source is provided for time-varying three-dimensional tomography;

the three-dimensional time-varying tomography mapping matrix construction module adopts a transformation technology, selects a proper mapping matrix and discretizes the space-time distribution of the ionosphere electron density; the mapping matrix is typically large and it may be taken to construct the matrix using different methods in different directions. One approach is to transform orthogonal basis functions, consisting of classical or physical models, into linear combinations of multidimensional basis functions by constructing a mapping matrix in the horizontal and vertical directions; another simple method is to use pixel basis functions;

the multi-resolution ionosphere tomographic inversion module flexibly gives the scale of the tomographic structure according to the quantity and distribution of available projection data in an inversion area, the projection data density is high, then the ionosphere structure with small and medium scale is reconstructed, the ionosphere electron density distribution map with large scale is reconstructed by inversion with sparse data, the scale of the inversion result of the first stage is maximum, the inversion result of the second stage is performed again on the result of the first stage, and the steps are analogized in a step-by-step manner, so that the scale of the ionosphere tomographic structure is gradually decreased, and the image is gradually refined;

as shown in fig. 3, the multi-band wide-scale ionosphere non-uniform volume structure parameter inversion software comprises a large-scale ionosphere disturbance reconstruction module based on space-time variation of ionosphere characteristic parameters and a small-scale ionosphere non-uniform volume parameter inversion module based on scintillation signal power spectrum analysis;

the large-scale ionosphere disturbance reconstruction module based on the space-time variation of the characteristic parameters of the ionosphere carries out differential calculation on time and space based on the data such as the ionosphere TEC and the scintillation index extracted by the measuring instrument to obtain the ionosphere disturbance parameters such as the horizontal gradient of the ionosphere ROTI and the TEC, and the evolution of the large-scale disturbance structural strength, the spatial distribution and the like of the ionosphere along with the time is reproduced; the module simultaneously utilizes the cooperative observation of a ground receiving station chain (network) to extract ionosphere large-scale traveling disturbance LS-TID information, and parameters such as amplitude, period, horizontal phase speed and the like;

the small-scale ionosphere non-uniform body parameter inversion module based on scintillation signal power spectrum analysis obtains ionosphere non-uniform body spectrum index, drift speed and non-uniform body intensity parameters by inversion based on ionosphere scintillation observation information of different satellites at the same moment and combining parameter information of an ionosphere non-uniform body experience model.

The low-orbit satellite beacon ionosphere measuring component comprises a VHF, UHF, L multi-band antenna, a low-orbit satellite signal radio frequency module, a low-orbit satellite signal intermediate frequency processing module and a low-orbit satellite ionosphere data processing module;

as shown in fig. 4, because the frequencies (VHF band, UHF band, L band) of the satellite beacon signal are far apart, the three bands are all orthogonal dipole antennas with active orthogonal feed, the polarization mode is circular polarization, and the antenna comprises a filter, a combiner, a low noise amplifier and a power supply module, and the radio frequency signals received by the antenna array enter the combiner after passing through the filters and the low noise amplifier of each frequency band, and are output after being combined by the combiner.

As shown in fig. 5, the low-orbit satellite signal radio frequency module comprises a receiving channel, a frequency synthesis part and a control circuit, and the main function is to convert the four-frequency band signal output by the antenna into an intermediate frequency signal of 1.7MHz, wherein the receiving channel performs the function of down-conversion; the frequency synthesis part provides local oscillation signals for all channels and provides reference clock signals for the intermediate frequency processing module; the control circuit is responsible for communicating with the intermediate frequency processing module, receiving the control command sent by the intermediate frequency processing module, and then completing various control functions.

As shown in fig. 6, the low-orbit satellite signal intermediate frequency processing module comprises a signal conditioning circuit and an FPGA chip, the intermediate frequency processing module firstly conditions intermediate frequency signals of three channels, then converts the intermediate frequency signals into numerical signals through an AD chip, inputs the numerical intermediate frequency signals into the FPGA chip for digital algorithm processing such as filtering and synchronization, and then outputs the numerical signals to the DSP chip for further signal capturing processing, and meanwhile, the intermediate frequency processing module controls the radio frequency module to complete various control functions.

The low-orbit satellite ionosphere data processing module comprises the functions of differential Doppler phase calculation, phase inversion judgment and identification, phase restoration and connection, phase smoothing filtering, ionosphere TEC calculation, ionosphere scintillation index S4 calculation and the like, and the module acquires the total electronic content TEC of the ionosphere of the low-orbit satellite beacon by acquiring the original observation values such as the signal intensity, the phase and the like of signals of three frequency bands at the sampling rate of 50Hz of the intermediate frequency processing module.

The GNSS satellite signal ionosphere measurement component comprises a GNSS antenna, a GNSS satellite signal receiving measurement module, a TEC and a flicker index calculation module.

The GNSS antenna adopts a mature choke coil antenna in the market; as shown in fig. 7, the GNSS satellite signal receiving and measuring module includes a radio frequency processing unit, a data acquisition unit, a baseband information processing unit, a navigation data resolving and observing amount extracting unit, a data interface unit and other functional units, and the module receives dual-frequency signals of satellite systems such as beidou, GPS and GLONASS, and performs tracking measurement on the dual-frequency signals to extract I, Q information, carrier phase and other original information;

the TEC and scintillation index calculation module is mainly used for calculating the ionized layer TEC and scintillation index, and adopts a hardware processing platform taking ARM as a core and an embedded software operating system. The module acquires the ionosphere TEC of the GNSS signals through the processes of observation data preprocessing, puncture point calculation, ionosphere observation equation construction, solution hardware delay, residual statistics, coarse difference detection, ionosphere TEC calculation and the like, and the module receives statistics and filtering processing on signal amplitude information (broadband power and narrowband power) and carrier phase information obtained by the GNSS satellite signal intermediate frequency module to complete calculation of a flicker index.

The data storage unit adopts a standard storage hard disk, and the capacity of the hard disk is not less than 1TB; the power supply unit adopts 220V commercial power, and a power supply conversion circuit is internally arranged in the power supply unit to convert alternating current into common direct current voltages of 12V, 5V, 3.3V and the like, so as to meet the power supply requirements of each module; the data display and control unit adopts a mature industrial computer and has the three-dimensional visual display capability of instrument parameter setting, data transmission, data receiving, log management and data products.

The low-orbit satellite beacon ionosphere measuring component, the GNSS satellite signal ionosphere measuring component, the data comprehensive processing unit, the data storage unit, the power supply unit and the data display and control unit are integrated on a universal bus hardware platform and adopt a unified interface design, and control signals and data information are transmitted by using a CPCI bus, so that each component completes ionosphere tomography measurement according to corresponding working flow and logic relation.

An observation method, using the ionospheric tomography measuring instrument based on the multi-band multi-constellation satellite signal, is described by taking ionospheric tomography networking observation as an example, and specifically comprises the following steps:

in a selected observation area, the observation of an regional ionosphere TEC, electron density and non-uniformity is realized by a networking observation method of at least 4 measuring instruments, wherein the mutual interval between the measuring instruments is not more than 500 km, the mutual communication capability is realized, the measuring instruments are powered by single-phase mains supply, and data communication is realized through the Internet or private network;

step 2, selecting a proper observation field, arranging ionosphere tomography measuring instruments in the appointed observation field, wherein the periphery of the arranged field is relatively wide, no obvious shielding exists, no receiver near the field receives interference signals in a frequency band, and each measuring instrument is grounded and is installed in an online UPS and power protection equipment; ensuring a sufficiently good view of each antenna and ensuring a stable and reliable mounting of the antennas.

Step 3, erecting an observation antenna outside the field, simultaneously installing an ionosphere tomography measuring instrument and an industrial personal computer in the same cabinet, transmitting measurement data to the industrial personal computer through a network cable by the ionosphere tomography measuring instrument, and exchanging information such as working instructions, time systems, working states, observation data and the like with the industrial personal computer;

step 4, after the ionosphere tomography measuring instrument is installed and operated, the equipment automatically transmits measurement data and working states to the industrial personal computer, personnel duty is not needed during normal operation of the equipment, and the remote data center can monitor the equipment states and receive data for processing and issuing;

installing equipment terminal software of the ionosphere tomography measuring instrument, receiving GNSS satellite and low-orbit satellite beacon data by the software, inverting the non-uniform body, transmitting data to central terminal software through the Internet or private network, and displaying related information and results;

and 6, installing center software in the data center, wherein the software receives data transmitted by a plurality of equipment terminal software through the Internet or private network, has the functions of multi-station data fusion processing, three-dimensional time-varying ionosphere tomography and the like, and is provided with a database at the same time, and the database is responsible for warehousing, storing and managing the data transmitted by an instrument terminal and the data obtained by the center processing.

Claims (9)

1. An ionospheric tomography measuring instrument based on multi-band multi-constellation satellite signals, which is characterized in that: the system comprises a data comprehensive processing unit, a low-orbit satellite beacon ionosphere measuring component, a GNSS satellite signal ionosphere measuring component, a data storage unit, a power supply unit and a data display control unit, wherein the low-orbit satellite beacon ionosphere measuring component is electrically connected with the data comprehensive processing unit;

the data comprehensive processing unit comprises a three-dimensional time-varying multi-scale ionosphere electron density tomography unit and a multi-band wide-scale ionosphere inhomogeneous structure parameter inversion unit;

the low-orbit satellite beacon ionosphere measuring component comprises a VHF, UHF, L multi-band antenna, a low-orbit satellite signal radio frequency module, a low-orbit satellite signal intermediate frequency processing module and a low-orbit satellite ionosphere data processing module;

the GNSS satellite signal ionosphere measuring component comprises a GNSS antenna, a GNSS satellite signal receiving and measuring module, a TEC and a flicker index calculating module;

the three-dimensional time-varying multiscale ionosphere electron density tomography unit comprises a low-orbit satellite beacon, a middle-high orbit GNSS data fusion processing module, a three-dimensional time-varying tomography mapping matrix construction module and a multi-resolution ionosphere tomographic inversion module;

the low-orbit satellite beacon and middle-high-orbit GNSS data fusion processing module is used for carrying out fusion processing on data obtained by receiving the low-orbit satellite beacon and the middle-high-orbit GNSS satellite signals, integrating and converting TEC into a matrix form, and fusing the observed data of the middle-high-orbit GNSS satellite and the low-orbit satellite beacon into a projection matrix based on a discretization characterization method of the total electronic content of an ionosphere, so as to obtain local high-density projection data;

the three-dimensional time-varying tomography mapping matrix construction module adopts a transformation technology, selects a proper mapping matrix and discretizes the space-time distribution of the ionosphere electron density; the construction method of the mapping matrix is that the orthogonal basis functions formed by classical or physical models are converted into linear combination of multidimensional basis functions by constructing the mapping matrix in the horizontal and vertical directions;

the multi-resolution ionosphere tomographic inversion module flexibly gives the scale of the tomographic structure according to the quantity and distribution of available projection data in an inversion area, the projection data density is high, then the ionosphere structure with small and medium scale is reconstructed, the ionosphere electron density distribution map with large scale is reconstructed by inversion with sparse data, the scale of the inversion result of the first stage is maximum, the inversion result of the second stage is performed again on the result of the first stage, and the steps are analogized in a step-by-step manner, so that the scale of the ionosphere tomographic structure is gradually decreased, and the image is gradually refined;

the multi-band wide-scale ionosphere non-uniform body structure parameter inversion unit comprises a large-scale ionosphere disturbance reconstruction module based on space-time variation of ionosphere characteristic parameters and a small-scale ionosphere non-uniform body parameter inversion module based on scintillation signal power spectrum analysis;

the large-scale ionosphere disturbance reconstruction module based on the space-time variation of the ionosphere characteristic parameters carries out differential calculation on time and space based on the ionosphere TEC and scintillation index data extracted by the measuring instrument to obtain horizontal gradient ionosphere disturbance parameters of the ionosphere ROTI and the TEC, and the evolution of the ionosphere large-scale disturbance structural strength and the spatial distribution along with the time is reproduced; the large-scale ionosphere disturbance reconstruction module simultaneously utilizes the cooperative observation of a ground receiving station chain and a network to extract ionosphere large-scale traveling disturbance LS-TID information, including amplitude, period and horizontal phase velocity parameters;

the small-scale ionosphere non-uniform body parameter inversion module based on scintillation signal power spectrum analysis obtains ionosphere non-uniform body spectrum index, drift speed and non-uniform body intensity parameters by inversion based on ionosphere scintillation observation information of different satellites at the same moment and combining parameter information of an ionosphere non-uniform body experience model.

2. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the VHF, UHF, L multiband antenna adopts an active orthogonal feed orthogonal dipole antenna, the polarization mode is circular polarization, the antenna comprises a filter, a combiner, a low-noise amplifier and a power supply module, and radio frequency signals received by the antenna array enter the combiner after passing through the filters and the low-noise amplifier of each frequency band, and are output after being combined by the combiner.

3. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the low-orbit satellite signal radio frequency module comprises a receiving channel, a frequency synthesis part and a control circuit, and converts a four-frequency-band signal output by an antenna into an intermediate frequency signal of 1.7MHz, wherein the receiving channel finishes down-conversion; the frequency synthesis part provides local oscillation signals for all channels and provides reference clock signals for the intermediate frequency processing module; the control circuit is responsible for communicating with the intermediate frequency processing module, receiving the control command sent by the intermediate frequency processing module, and then completing various control functions.

4. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the low-orbit satellite signal intermediate frequency processing module comprises a signal conditioning circuit and an FPGA chip, the intermediate frequency processing module firstly conditions intermediate frequency signals of three channels, then converts the intermediate frequency signals into numerical signals through the AD chip, inputs the numerical intermediate frequency signals into the FPGA chip for filtering and synchronization, then outputs the numerical intermediate frequency signals to the DSP chip for further completing the capturing processing of the signals, and meanwhile, the intermediate frequency processing module controls the radio frequency module to complete various control functions.

5. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the low-orbit satellite ionosphere data processing module outputs the signal intensity and the phase of three frequency band signals in real time by acquiring the sampling rate of 50Hz of the intermediate frequency processing module, and acquires the total electronic content TEC of the ionosphere of the low-orbit satellite beacon.

6. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the GNSS antenna adopts a choke coil antenna; the GNSS satellite signal receiving and measuring module comprises a radio frequency processing unit, a data acquisition unit, a baseband information processing unit, a navigation data resolving and observing quantity extracting unit and a data interface unit, and is used for receiving the double-frequency signals of the Beidou, GPS and GLONASS satellite systems, carrying out tracking measurement on the double-frequency signals and extracting I, Q information and carrier phase original information; the TEC and scintillation index calculation module adopts a hardware processing platform taking ARM as a core, the TEC and scintillation index calculation module obtains an ionized layer TEC of GNSS signals through observation data preprocessing, puncture point calculation, ionosphere observation equation construction, solution hardware delay, residual error statistics and coarse difference detection, and ionosphere TEC calculation, and the TEC and scintillation index calculation module receives statistics and filtering processing on signal amplitude information and carrier phase information obtained by the GNSS satellite signal intermediate frequency module to complete calculation of scintillation indexes.

7. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the data storage unit adopts a standard storage hard disk, and the capacity of the hard disk is not less than 1TB; the power supply unit adopts 220V commercial power, and a power supply conversion circuit is internally arranged in the power supply unit to convert alternating current into 12V, 5V and 3.3V direct current voltages for meeting the power supply requirements of each module; the data display and control unit adopts an industrial computer.

8. Ionospheric tomography meter based on multi-band multi-constellation satellite signals according to claim 1, characterized in that: the low-orbit satellite beacon ionosphere measuring component, the GNSS satellite signal ionosphere measuring component, the data comprehensive processing unit, the data storage unit, the power supply unit and the data display and control unit are integrated on a universal bus hardware platform and adopt a unified interface design, and control signals and data information are transmitted by using a CPCI bus.

9. An observation method using the ionospheric tomography measurement instrument based on multi-band multi-constellation satellite signals according to claim 1, characterized by comprising the steps of:

in a selected observation area, the observation of an regional ionosphere TEC, electron density and non-uniformity is realized by a networking observation method of at least 4 measuring instruments, wherein the mutual interval between the measuring instruments is not more than 500 km, the mutual communication capability is realized, the measuring instruments are powered by single-phase mains supply, and data communication is realized through the Internet or private network;

step 2, arranging measuring instruments in a designated observation field, wherein no receiver near the field receives interference signals in a frequency band, and grounding each measuring instrument and installing on-line UPS and power protection equipment;

step 3, erecting an observation antenna outside the field, simultaneously installing a measuring instrument and an industrial personal computer in the same cabinet, transmitting measurement data to the industrial personal computer by the measuring instrument through a network cable, and exchanging working instructions, time systems, working states and observation data with the industrial personal computer;

step 4, after the measuring instrument is installed and operated, the measuring data and the working state are automatically transmitted to the industrial personal computer, the equipment state is monitored in a remote data center, and the data is received for processing and release;

step 5, the measuring instrument receives the GNSS satellite and the low orbit satellite beacon data, performs non-uniform inversion, and performs data transmission, information and result display to the central end through the Internet or private network;

and 6, the data center receives data transmitted by each measuring instrument through the Internet or a private network, performs multi-station data fusion processing and three-dimensional time-varying ionosphere tomography, is provided with a database, and is responsible for warehousing, storing and managing the data transmitted by the measuring instrument and the data processed by the data center.

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