CN113433573B

CN113433573B - Method and device for positioning radiation sources by multiple satellites in combined mode and electronic equipment

Info

Publication number: CN113433573B
Application number: CN202110620750.9A
Authority: CN
Inventors: 朱建丰; 何新生
Original assignee: CETC 36 Research Institute
Current assignee: CETC 36 Research Institute
Priority date: 2021-06-03
Filing date: 2021-06-03
Publication date: 2023-06-02
Anticipated expiration: 2041-06-03
Also published as: CN113433573A

Abstract

The application discloses a method, a device and electronic equipment for jointly positioning a radiation source by multiple satellites. The method for positioning the radiation source by combining multiple satellites comprises the steps of firstly obtaining time reference errors and frequency reference errors, which are obtained by calibration, of multiple satellites aiming at an uncorrelated multiple satellite system with overlapped working frequency bands; then in a certain time span, receiving a radiation source signal emitted by a radiation source, digitally sampling the radiation source signal, downloading the sampled radiation source signal to a ground data processing system for time difference and frequency difference processing, establishing a time difference equation and a frequency difference equation by using the time reference error and the frequency reference error, and finally solving the time difference equation and the frequency difference equation to realize high-precision positioning of the radiation source. The method solves the difficult problem of non-relevant multi-star combined high-precision positioning, can realize high-precision positioning of all interested targets in the overlapped working frequency bands in a certain duration span through single calibration, and has wide application prospect.

Description

Method and device for positioning radiation sources by multiple satellites in combined mode and electronic equipment

Technical Field

The application relates to the technical field of radio positioning, in particular to a method and a device for multi-satellite combined positioning of a radiation source and electronic equipment.

Background

Multi-satellite Time Difference (TDOA) or time frequency difference (TDOA/FDOA) positioning systems are one of the means for obtaining a high accuracy positioning of the radiation source. In general, from the beginning of design, the positioning system is considered according to multi-star formation, a complex inter-star link and an ultra-stable rubidium clock are arranged between satellites, and the time reference and the frequency reference of the positioning system are realized through the inter-star link.

However, in the actual situation, the satellite design possibly has more satellites, and the application of the multi-star positioning technology is not considered, but only the single-star positioning technology is adopted, so that the positioning precision is lower, and the combat requirement cannot be met; or in the event that one or more satellites fail in some multi-satellite positioning systems, multi-satellite positioning is likewise not possible.

Disclosure of Invention

In view of the above, the main objective of the present application is to provide a method, an apparatus and an electronic device for positioning radiation sources by multiple satellites in a combined manner, which are used for solving the technical problem of poor positioning accuracy of the radiation source positioning method in the prior art.

According to a first aspect of the present application there is provided a method of co-locating a radiation source with a plurality of satellites having overlapping operating frequency bands, the method comprising:

Acquiring time reference errors and frequency reference errors of the plurality of satellites;

receiving radiation source signals emitted by the radiation sources through the satellites, and adjusting receiver frequency setting parameters of the satellites so that the frequency of the radiation source signals is in a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is in an overlapping working frequency band of the satellites;

digitally sampling the received radiation source signals through a plurality of satellites to obtain sampled radiation source signals and downloading the sampled radiation source signals to a ground data processing system;

acquiring the measured time difference and the measured frequency difference of the sampled radiation source signals at the receiving moment;

establishing a time difference equation according to the time reference errors of the satellites and the measured time difference of the sampled radiation source signals at the receiving time, and establishing a frequency difference equation according to the frequency reference errors of the satellites and the measured frequency difference of the sampled radiation source signals at the receiving time;

and positioning the radiation source through the time difference equation and the frequency difference equation.

According to a second aspect of the present application there is provided an apparatus for co-locating a radiation source with a plurality of satellites having overlapping operating frequency bands, the apparatus comprising:

A reference error acquisition unit configured to acquire time reference errors and frequency reference errors of the plurality of satellites;

the radiation source signal receiving unit is used for receiving radiation source signals emitted by the radiation sources through the satellites and adjusting receiver frequency setting parameters of the satellites so that the frequency of the radiation source signals is in a first receiver instantaneous working frequency range, wherein the first receiver instantaneous working frequency range is in an overlapping working frequency range of the satellites;

the digital sampling unit is used for digitally sampling the received radiation source signals through a plurality of satellites to obtain sampled radiation source signals and downloading the sampled radiation source signals to the ground data processing system;

the measuring time difference and measuring frequency difference acquisition unit is used for acquiring the measuring time difference and the measuring frequency difference of the sampled radiation source signal at the receiving moment;

a time difference equation and frequency difference equation establishing unit, configured to establish a time difference equation according to time reference errors of the plurality of satellites and a measured time difference of the sampled radiation source signals at a receiving time, and establish a frequency difference equation according to frequency reference errors of the plurality of satellites and a measured frequency difference of the sampled radiation source signals at the receiving time;

And the radiation source positioning unit is used for positioning the radiation source through the time difference equation and the frequency difference equation.

According to a third aspect of the present application, there is provided an electronic device comprising: a processor, a memory storing computer executable instructions,

the executable instructions, when executed by the processor, implement the aforementioned method of multi-satellite joint positioning of radiation sources.

According to a fourth aspect of the present application, there is provided a computer readable storage medium storing one or more programs which, when executed by a processor, implement the aforementioned method of multi-satellite joint positioning of radiation sources.

The beneficial effects of this application are: the method for positioning the radiation source by combining the multiple satellites is aimed at a non-relevant multiple satellite system without a time reference and a frequency reference but with an overlapped working frequency band, and firstly, time reference errors and frequency reference errors obtained by calibrating the multiple satellites are obtained; and then in a certain time span, adjusting the frequency setting parameters of the satellite receiver according to the frequency of the radiation source, enabling the frequency of the radiation source signal to be in the instantaneous working frequency band of the first receiver, digitally sampling the radiation source signal, carrying out time difference and frequency difference processing after the sampled radiation source signal is downloaded to a ground data processing system, and finally, applying the time reference error and the frequency reference error to realize the high-precision positioning of the radiation source based on the time difference or the time frequency difference. The method solves the difficult problem of the non-relevant multi-satellite combined high-precision positioning, can bring a plurality of non-relevant satellites into a positioning system, and can realize the high-precision positioning of all interested targets in the multi-satellite overlapped working frequency range within a certain duration span after single calibration, so that the method has wide application prospect in the aspect of multi-satellite high-precision positioning.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIG. 1 is a flow chart of a method for multi-satellite joint positioning of radiation sources according to one embodiment of the present application;

FIG. 2 is a schematic structural diagram of a dual-star frequency measurement positioning system according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a satellite, a ground calibration station, and a radiation source according to an embodiment of the present disclosure;

FIG. 4 is a block diagram of a calibration flow based on non-real-time digital sampling according to one embodiment of the present application;

FIG. 5 is a schematic diagram of the position relationship between the satellite sub-satellite point track and the calibration station, target radiation source according to one embodiment of the present application;

FIG. 6 is a plot of a dual-satellite time-frequency difference positioning CEP after ground calibration in accordance with one embodiment of the present application;

FIG. 7 is a block diagram of an apparatus for multiple satellite joint positioning radiation sources according to one embodiment of the present application;

fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein.

Fig. 1 is a flow chart of a method for multi-satellite joint positioning of a radiation source according to an embodiment of the present application, referring to fig. 1, where a plurality of satellites of the embodiment of the present application have overlapping operating frequency bands, the method for multi-satellite joint positioning of a radiation source of the embodiment of the present application includes steps S110 to S160 as follows:

step S110, acquiring time reference errors and frequency reference errors of a plurality of satellites;

step S120, receiving radiation source signals emitted by the radiation sources through a plurality of satellites, and adjusting receiver frequency setting parameters of each satellite so that the frequency of the radiation source signals is in a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is in a working frequency band overlapped by the satellites;

Step S130, digital sampling is carried out on the received radiation source signals through a plurality of satellites, and the sampled radiation source signals are obtained and are downloaded to a ground data processing system;

step S140, obtaining the measured time difference and the measured frequency difference of the sampled radiation source signal at the receiving moment;

step S150, a time difference equation is established according to the time reference errors of the satellites and the measured time difference of the sampled radiation source signals at the receiving time, and a frequency difference equation is established according to the frequency reference errors of the satellites and the measured frequency difference of the sampled radiation source signals at the receiving time;

step S160, positioning the radiation source is achieved through a time difference equation and a frequency difference equation.

The method for positioning the radiation source by combining the multiple satellites is aimed at a non-relevant multiple satellite system without a time base and a frequency base but with an overlapped working frequency band, and firstly, time reference errors and frequency reference errors obtained by calibrating the multiple satellites are obtained; and then in a certain time span, adjusting the frequency setting parameters of the satellite receiver according to the frequency of the radiation source, enabling the frequency of the radiation source signal to be in the instantaneous working frequency band of the first receiver, digitally sampling the radiation source signal, carrying out time difference and frequency difference processing after the sampled radiation source signal is downloaded to a ground data processing system, and finally, applying the time reference error and the frequency reference error to realize the high-precision positioning of the radiation source based on the time difference or the time frequency difference.

The method solves the difficult problem of the combined high-precision positioning of the uncorrelated multiple satellites, can bring multiple uncorrelated satellites into a positioning system, and has wide application prospect in the aspect of the high-precision positioning of multiple satellites because the digital sampling is completed on the satellites, so that the high-precision positioning of all interested targets in the overlapping working frequency bands of the multiple satellites can be realized within a certain duration span after single calibration.

It should be noted that, the number of satellites for the method for positioning the radiation source by combining multiple satellites in the embodiment of the application may be two, or may be any number of more than two, for example, the method for positioning the radiation source by combining multiple satellites in the application may be applied to an uncorrelated double-satellite/triple-satellite positioning system, and may implement high-precision positioning of a ground stationary or slow target by a double-satellite time-frequency-difference positioning technique/a triple-satellite time-difference positioning technique; or can also be applied to an uncorrelated four-star positioning system, and can realize high-precision positioning of an aerial target by a four-star time difference positioning technology and the like.

To facilitate an understanding of the various embodiments of the present application, the following embodiments are described by taking as an example a positioning system consisting of two non-associated satellites.

In one embodiment of the present application, acquiring the time reference error and the frequency reference error for a plurality of satellites includes: transmitting calibration signals through a ground calibration station, and adjusting receiver frequency setting parameters of each satellite so that the frequency of the calibration signals is in a second receiver instantaneous working frequency band, wherein the second receiver instantaneous working frequency band is in an overlapped working frequency band; receiving calibration signals through a plurality of satellites, digitally sampling the calibration signals, obtaining sampled calibration signals, and downloading the sampled calibration signals to a ground data processing system; extracting the measured time difference and the measured frequency difference of the sampled calibration signals, and extracting the real time difference and the real frequency difference of the sampled calibration signals reaching a plurality of satellites; determining time reference errors of the plurality of satellites according to the measured time difference of the sampled calibration signals and the real time difference of the sampled calibration signals reaching the plurality of satellites, and determining frequency reference errors of the plurality of satellites according to the measured frequency difference of the sampled calibration signals, the real frequency difference of the sampled calibration signals reaching the plurality of satellites and the frequency of the sampled calibration signals.

As shown in fig. 2, a schematic structural diagram of a dual star frequency measurement positioning system according to an embodiment of the present application is provided. The double-star frequency measurement positioning system mainly comprises a satellite i, a satellite j, a ground calibration station, a radiation source and a ground data processing system.

Based on the double-satellite frequency measurement positioning system, when acquiring the time reference error and the frequency reference error of two satellites, the embodiment of the application can firstly utilize the satellite i and the satellite j to respectively receive the calibration signals transmitted by the ground calibration station, and the satellite i and the satellite j can be regarded as having an overlapped working frequency band M _f The instantaneous operating frequency band of the second receiver of satellite i and satellite j needs to be located in the overlapping operating frequency band M of these two satellites _f In the second receiver, the frequency of the calibration signal transmitted by the ground calibration station also needs to be within the instantaneous operating frequency band of the second receiver, so that the transmitted calibration signal can be received by the satellite i and the satellite j simultaneously.

It should be noted that, the second receiver instantaneous operating frequency band and the first receiver instantaneous operating frequency band of the above embodiment are independent of each other, and may be the same or different, for example, the frequency of the calibration signal transmitted by the ground calibration station may be N _f2 (N _f2 ∈M _f ) The frequency of the radiation source signal emitted by the radiation source may be N _f1 (N _f1 ∈M _f )。

The working frequency ranges of the calibration signal and the radiation source signal are mutually independent, so that the frequency setting parameters of the receiver on the satellite can be flexibly adjusted when the radiation source signal is transmitted, and the frequency of the radiation source signal is only required to be in the instantaneous working frequency range of the first receiver, so that the radiation source signal in the whole working frequency range can be positioned by single calibration.

Then, the satellite i and the satellite j respectively carry out digital sampling on the calibration signals, the sampled calibration signals are downloaded to a ground data processing system to obtain sampled calibration signals, and the ground data processing system adopts a direct or indirect method to extract the measurement time difference and the measurement frequency difference of the sampled calibration signals and the real time difference and the real frequency difference of the sampled calibration signals reaching the satellite i and the satellite j from the sampled calibration signals. And finally, establishing a time reference error of the double-star positioning system according to the measured time difference of the sampled calibration signal and the real time difference of the sampled calibration signal reaching the satellite i and the satellite j, and establishing a frequency reference error of the double-star positioning system according to the measured frequency difference of the sampled calibration signal and the real frequency difference of the sampled calibration signal reaching the satellite i and the satellite j.

In one embodiment of the present application, extracting the real time differences and the real frequency differences of the sampled calibration signals to the plurality of satellites includes: determining a ground calibration station, a position vector and a relative speed vector of each satellite in a geocentric fixedly connected system, and the frequency of a calibration signal; extracting the real time difference of the sampled calibration signals reaching a plurality of satellites according to the ground calibration station and the position vector of each satellite in the earth center fixedly connected system; and extracting the actual frequency difference of the sampled calibration signals reaching a plurality of satellites according to the ground calibration station, the position vector and the relative speed vector of each satellite in the earth center fixedly connected system and the frequency of the calibration signals.

As shown in fig. 3, a schematic diagram of the positional relationship of the satellite, the ground calibration station, and the radiation source under the ground center fastening system according to an embodiment of the present application is provided.

When the true time difference and the true frequency difference of the sampled calibration signals reaching the satellite i and the satellite j are extracted, the GPS data acquired by the ground data processing system can be utilized to determine t ₁ The time ground calibration station (B) is fixedly connected with the ground center (S) _e ) Lower position vector r _b And a relative velocity vector v _b Satellite i (S _i ) Position vector r of (2) _i1 And a relative velocity vector v _i1 Satellite j (S) _j ) Position vector r of (2) _j1 And a relative velocity vector v _j1 And the frequency f of the calibration signal _b The calibration signal reaches S _i 、S _j Is the true time difference t of (2) _ij ^bt And true frequency difference f _ij ^bt Can be represented by formula (1) and formula (2), respectively:

thereafter, S _i 、S _j The received calibration signals are digitally sampled and then downloaded to a ground data processing system, and the ground data processing system extracts the sampled calibration signals to S through a direct or indirect method _i 、S _j Is a measured time difference t _ij ^bm And measuring frequency difference f _ij ^bm . Then, the time reference error delta t of the uncorrelated multi-star positioning system established based on the calibration signal _ij And a frequency reference error Δref _ij Can be expressed as formula (3) and formula (4), respectively:

Δt _ij ＝t _ij ^bt -t _ij ^bm ， (3)

because the calibration signal transmitted by the ground calibration station is sampled on two satellites and then is transmitted to the ground data processing system, the frequency of the calibration signal directly influences the calculation of the real frequency difference and the measured frequency difference, and therefore the frequency reference error delta ref is calculated _ij Can further consider the calculation of the calibration signalFrequency f _b This can be expressed in a normalized manner.

In one embodiment of the present application, establishing a time difference equation based on time reference errors of the plurality of satellites and a measured time difference of the sampled radiation source signals at the receiving time, and establishing a frequency difference equation based on frequency reference errors of the plurality of satellites and a measured frequency difference of the sampled radiation source signals at the receiving time includes: determining a position vector and a relative speed vector of the radiation source, each satellite in the geocentric fastening system, and the frequency of the radiation source signal; correcting the time reference errors of a plurality of satellites according to the frequency reference errors and the time difference between the radiation source signals and the calibration signals, and establishing a time difference equation according to the corrected time reference errors of the plurality of satellites, the measured time difference of the sampled radiation source signals and the position vector of the radiation source and each satellite in the earth center fixedly connected system; correcting the frequency reference error according to the frequency of the radiation source signal, and establishing a frequency difference equation according to the corrected frequency reference error, the measured frequency difference of the sampled radiation source signal, the position vector and the relative speed vector of the radiation source and each satellite in the earth center fixedly connected system and the frequency of the radiation source signal.

Time reference error Δt based on the above embodiment _ij And a frequency reference error Δref _ij The multi-star positioning method can be used as a compensation value, and a time difference equation and a frequency difference equation of a non-relevant multi-star positioning system are established by considering certain correction, and after the time difference equation and the frequency difference equation are obtained, the multi-star positioning of the radiation source can be performed.

Specifically, at t ₂ At the moment, the radiation source signal is S _i 、S _j Receiving, the receiver on the satellite digitally samples the signal and then downloads the signal to the ground data processing system, and the ground data processing system extracts the sampled radiation source signal to arrive at S _i 、S _j Is a measured time difference t _ij ^pm And measuring frequency difference f _ij ^pm . Then, the time reference error Δt is compensated _ij And a frequency reference error Δref _ij And taking certain correction value into consideration to obtain radiation source signal reaching satellite S _i 、S _j Is the true time difference t of (2) _ij ^pt And true frequency difference f _ij ^pt The following formulas (5) and (6) show:

t _ij ^pt ＝t _ij ^pm +Δt _ij -Δref _ij (t ₂ -t ₁ )+ξ _ij ， (5)

f _ij ^pt ＝f _ij ^pm +Δref _ij ·f _p +ε _ij ， (6)

wherein Deltref _ij (t ₂ -t ₁ ) For correction of time scale drift of sampled data due to frequency source accuracy, f _p Is the frequency of the radiation source signal, ζ _ij 、ε _ij Respectively after passing the calibration, S _i 、S _j The time reference residual error and the frequency reference residual error between are random gaussian white noise, the variance of which becomes larger with time, and can be considered as constant values within a certain time span, wherein the time span depends on the tolerable positioning accuracy.

At t ₂ At moment, the position vector and the relative velocity vector of the radiation source in the earth center fixedly connected system are respectively r _p 、v _p ，S _i The position vector and the relative velocity vector in the earth center fixed connection are respectively r _i2 、v _i2 ，S _j The position vector and the relative velocity vector in the earth center fixed connection are respectively r _j2 、v _j2 Frequency f of the radiation source signal _p The equation of time difference and the equation of frequency difference including the position of the radiation source can be expressed as formula (7) and formula (8), respectively:

by combining the above equations (7) and (8), the position vector r of the radiation source can be solved _p And the relative velocity vector is v respectively _p Thereby realizing high-precision positioning of the radiation source.

It should be noted that although the accuracy of the frequency source on the satellite can be calibrated, the stability cannot be calibrated, and the timing on the satellite is based on the frequency source, so the frequency source needs to have a high stability, so that the effect on the time scale of the sampled data in a certain time span is negligible.

Further, t of the above embodiment ₁ Time sum t ₂ The time is not equal, namely, the time is not real-time, so compared with a method for realizing multi-star positioning by carrying out real-time calibration on associated signals, the method and the device for realizing multi-star positioning do not need to carry out digital sampling on the calibration signals and the radiation source signals by a receiver on a satellite at the same time, and therefore, the application of the method and the device has higher flexibility and stronger concealment.

In one embodiment of the present application, the positioning of the radiation source by the equation of time difference and the equation of frequency difference includes: determining a type of radiation source; if the type of the radiation source is a ground target, establishing a geosphere constraint equation according to the position vector of the radiation source, and realizing the positioning of the radiation source according to the geosphere constraint equation, the time difference equation and the frequency difference equation; if the type of the radiation source is a non-ground target, the radiation source is positioned directly through a time difference equation and a frequency difference equation.

In practical application, the types of the radiation source can be two, one is a ground radiation source and the other is a non-ground radiation source, and if the radiation source to be positioned currently is determined to be the ground radiation source according to priori information, the position of the radiation source is also subject to a geodesic constraint, as shown in the following formula (9):

wherein [ x ] _p ,y _p ,z _p ] ^T ＝r _p A and e are the earth semi-long axis and the flat rate, respectively.

Simultaneous equations (7), (8) and (9) and thus high accuracy positioning of the radiation source can be achieved by solving the system of equations.

In one embodiment of the present application, transmitting the calibration signal by the ground calibration station comprises: the receiver channelized sampling parameters on the plurality of satellites are set to be the same as the receiver channelized sampling parameters at calibration.

The receiver-channelized sampling parameters on the satellite according to the embodiment of the present application need to be consistent with the receiver-channelized sampling parameters at calibration time, so that the time reference error calculated by the above embodiment can be applied.

In addition, in engineering application, because the data after digital sampling can be stored on the satellite, the ground receiving station is not required to be in the visible range of the satellite at any time, the data after digital sampling can be downloaded to ground for receiving in a non-real-time mode, and the application range of the method for jointly positioning the radiation source by the multiple satellites in the embodiment of the application is greatly expanded.

In one embodiment of the present application, the method further comprises: performing accuracy analysis on time reference errors and frequency reference errors of a plurality of satellites; calculating the total error of the time difference measurement according to the accuracy analysis result of the time reference error, and calculating the total error of the frequency difference measurement according to the accuracy analysis result of the frequency reference error; the total time difference measurement error is the sum of the time reference residual error, the time difference error in the accumulated time during positioning and the time difference estimation error, and the total frequency difference measurement error is the sum of the frequency reference residual error, the frequency difference error in the accumulated time during positioning and the frequency difference estimation error of the radiation source signal; and carrying out precision evaluation on the positioning result of the radiation source according to the total time difference measurement error and the total frequency difference measurement error.

In order to further measure the positioning accuracy of the method for positioning the radiation source by combining multiple satellites in the embodiment, the time reference and the frequency reference after calibration are subjected to accuracy analysis, and the total time difference measurement error and the total frequency difference measurement error of the positioning system are calculated on the basis of the accuracy analysis.

As shown in FIG. 4, a block diagram of a calibration flow based on non-real-time digital sampling is provided in accordance with one embodiment of the present application. Calibration signals transmitted by the ground calibration station are transmitted by satellite S _i And S is _j After receiving, digitally sample and download itThe surface data processing system, the ground data processing system respectively reaches S through calibration signals _i And S is _j And (3) combining the time difference and the frequency difference of the satellite platform to obtain the time reference precision and the frequency reference precision of the calibrated uncorrelated multi-star positioning system.

The specific calculation process is as follows:

(1) Time reference accuracy analysis after calibration

Based on the ground calibration signal, the relative satellite errors of the digital sampling channels between two satellites, the relative analog down-conversion channel delay and the relative AD sampling/channelizing delay can be calibrated, and meanwhile, the uplink path delay errors, the time difference errors in the accumulated time and the ground processing errors are introduced, so that the calibrated time reference residual errors mainly comprise:

(a) Uplink path delay error: the error is mainly determined by satellite position error due to fixed position of the ground calibration station caused by the distance between the ground calibration station and the satellite, and cannot be eliminated due to the change of satellite position error with time. Assume that the orbit determination precision of two satellites is sigma respectively _si 、σ _sj The delay error between two stars due to path propagation can be expressed as

(b) Time difference error in accumulated time of calibration: the value is smaller when the orbits are similar and is larger when the orbits differ greatly, caused by the relative motion between the satellite platforms. The value is represented as an uncertainty random error, which can be expressed as sigma _rt ；

(c) Satellite up-sampling time point error: the data sampling time point of the receiving channel and the data packaging time stamp cannot be aligned completely, and a certain deviation exists, which can be represented by the counting point error of the AD counter. Assume that the sampling frequencies of two satellites are f respectively _si 、f _sj The error of the count point of the on-board AD counter is N (preferably 2), and the time delay error caused by the error can be expressed as

(d) The on-satellite AD counter counts drift errors: the AD counter may indicate time, the counting errors of which are mainly linear deviations and drift errors, the former being linear with time and the latter being random with time. After ground calibration, the linear deviation can be compensated, the drift error cannot be compensated, and the linear deviation is related to the short-term stability of the frequency source and the calibration time interval. Assume that the short-term stability of the frequency sources of the two satellites is sigma _fi 、σ _fj The maximum drift error in the calibration time interval t is about

(c) Ground time difference estimation error: time error sigma, primarily for time-frequency difference estimation _ct 。

To sum up, based on the calibration signal, the time reference residual error after calibration by non-real-time digital sampling, i.e. the time reference precision, can be expressed as:

(2) Frequency reference accuracy analysis after calibration

Based on the calibration signal, the frequency error (fixed deviation) of the analog down-conversion channel and the AD sampling/channelizing frequency error (fixed deviation) can be calibrated, and meanwhile, the uplink Doppler frequency shift error, the frequency difference error in the accumulated time and the ground processing error are introduced, so that the calibrated frequency reference residual error mainly comprises:

(a) Uplink doppler shift error: the error is mainly determined by satellite position and speed errors due to the fact that the ground calibration station is fixed in position and the errors of the ground calibration station are caused by projection of the relative movement speed of the ground calibration station and the satellite on a relative position vector, and the errors cannot be eliminated and are shown as uncertain random errors due to the fact that the satellite position and speed errors change with time. Assume two pairsThe speed measurement errors of the satellites are sigma respectively _vi 、σ _vj The calibration source uplink frequency is f _b The maximum doppler shift errors can be expressed as

(

Is satellite S _i Edge-to-satellite S of antenna beam of (2) _i Maximum included angle with the connecting line of the earth center),

(

Is satellite S _j Edge-to-satellite S of antenna beam of (2) _j Maximum angle with the geocentric line), then the upstream doppler shift error σ between two stars _udi j can be expressed as:

(b) Frequency difference error in accumulated time during calibration: the value is smaller when the orbits are similar and is larger when the orbits differ greatly, caused by the relative motion between the satellite platforms. The value is represented as an uncertainty random error, which can be expressed as sigma _rf ；

(c) Digital sampling channel relative frequency drift error: the digital sampling channel relative frequency error comprises an analog down-conversion part and an AD/channelized sampling part, and is mainly determined by satellite payload frequency source error and channel characteristics and is divided into fixed deviation and short-term drift error. After ground calibration, the fixed offset can be compensated, short-term drift errors cannot be compensated, and the short-term drift errors are related to the short-term stability of the signal frequency and the frequency source (calibration intervals need to be considered, corresponding to different stabilities, and different drift errors are obtained) with time.

Assume that the frequency stability of two satellites is sigma _fi 、σ _fj The signal frequency of the radiation source is f _p The maximum relative frequency drift error of the digital sampling channel obtained after calibration can be expressed as

(d) Sampling frequency relative drift error: the sampling frequency relative error includes a fixed frequency offset that is relatively constant and a drift error that varies with time. After ground calibration, the fixed frequency offset can be compensated, the drift error cannot be compensated, and the fixed frequency offset is related to the short-term stability of the frequency source (the calibration interval needs to be considered, and different drift errors are obtained corresponding to different stabilities). Assume that the short-term stability of the frequency sources of the two satellites is sigma _fi 、σ _fj The sampling frequency is f _si 、f _sj The maximum relative drift error of the sampling frequency obtained after calibration can be expressed as

(e) Ground calibration signal frequency difference estimation error: frequency error sigma, primarily for time-frequency difference estimation of calibration signals _cf 。

To sum up, based on the calibration signal, the frequency reference residual error after calibration by non-real-time digital sampling, i.e. the frequency reference precision, can be expressed as:

as can be seen from equation (12) above, the frequency reference accuracy is related to the stability of the frequency source, which in turn is related to the time span (the longer the time span, the worse the stability), so the reference frequency accuracy varies with time and can be considered to be a constant value over a certain time span after calibration by the ground.

Based on the above embodiment, the time reference precision and the frequency reference precision of the positioning system are obtained after the ground calibration. Then, the total time difference measurement error of the non-correlated multi-star combined high-precision positioning system based on the non-real-time digital sampling calibration can be expressed as the sum of time reference precision, time difference error in the accumulated time of positioning and time difference estimation error; the total error of the frequency offset measurement can be expressed as the sum of the frequency reference accuracy, the frequency offset error in the accumulated time at the time of positioning, and the frequency offset estimation error of the target signal. Based on the total error of time difference measurement, the total error of frequency difference measurement, satellite positioning accuracy and the set of positioning equations, CEP (Circular Error Probable, circular probability error) distribution of system positioning accuracy can be obtained, and specific deductions of the embodiments of the present application will not be described in detail.

In order to verify the positioning effect of the method for positioning the radiation source by combining multiple satellites in the embodiment of the application, the embodiment of the application also provides a positioning accuracy analysis process of the double-satellite combined positioning radiation source. A high-precision positioning system combining an uncorrelated low-orbit satellite with a high-orbit satellite is first established, and then the CEP distribution of the positioning system is given.

The low orbit satellite is in a solar synchronous orbit with the height of 800km, the beam width of the antenna is 120 degrees, the high orbit satellite is in a geosynchronous orbit, the beam width of the antenna is 5 degrees, and the relative position relationship of the two is shown in figure 5.

The position self-positioning error of the low orbit satellite is 5m (1 sigma), the speed self-positioning error is 0.1m/s (1 sigma), the position self-positioning error of the high orbit satellite is 500m (1 sigma), and the speed self-positioning error is 1m/s (1 sigma). Because two stars do not have a co-design consideration, there is no frequency reference between the two stars, or the error of the frequency reference is very large (more than tens of kHz or hundreds of kHz), and meanwhile, the time service modes of the satellite platforms can be different, so that the error of the two stars time reference is also very large (possibly in the range of seconds), and therefore, the time-frequency difference positioning of the two stars combination cannot be carried out at all.

Based on this, in order to solve the high-precision positioning of the double-star combination, a ground calibration is necessary. As shown in fig. 5, a ground calibration station (BJZ) and a target radiation source (clip) exist on the ground, a low-orbit satellite and a high-orbit satellite first co-watch the calibration station, a calibration signal (with the frequency of 280 MHz) is transmitted through the calibration station, the low-orbit satellite and the high-orbit satellite simultaneously digitally sample the calibration signal and then download the signals to the ground, and a ground data processing system performs system calibration. After calibration, the fixed errors can be eliminated, and finally the available time reference precision and frequency reference precision are calculated according to formulas (10) and (12) respectively.

The initial conditions and the final results of the time reference accuracy calculation are shown in table 1, and the time interval for calibration is 1 hour, so that the time reference accuracy of two stars after calibration is better than the calculated value within 1 hour, and the time span is longer than 1 hour, and the time calibration needs to be carried out again.

TABLE 1

High orbit satellite positioning accuracy (m)	500
		Low orbit satellite positioning accuracy (m)	5
High orbit satellite sampling frequency (MHz)	56
		Low orbit satellite sampling frequency (MHz)	500
Counting point error of AD counter	2
		High orbit satellite frequency source stability (second stability)	1.00E-10
Low orbit satellite frequency source stability (second stability)	1.00E-10
		Calibration time interval t(s)	3600
Uplink path delay error (ns)	1667
		Time difference error (ns) in accumulated time of calibration	500
On-satellite sampling time point error (ns)	36
		On-board AD counter count drift error (ns)	170
Ground time difference estimation error (ns)	150
		Residual error of time reference (ns)	1755

Let the time difference error in the accumulated time of positioning be 1000ns, the time difference estimation error of the target signal be 600ns, then the total error of time difference measurement be 2124ns, as shown in table 2.

TABLE 2

Residual error of time reference (ns)	1775
		PositioningTime difference error (ns) in time accumulation	1000
Signal time difference estimation error (ns)	600
		Total error of time difference measurement (ns)	2124

The initial conditions and the final results of the frequency reference accuracy calculation are given in table 3, the stability of the satellite frequency source and the stability of the ground frequency source are both given in table 3, so that the calibrated two-star frequency reference accuracy is better than the calculated value within 1 hour, and the frequency calibration needs to be carried out again after the time span is longer than 1 hour.

TABLE 3 Table 3

High orbit satellite speed measuring precision (m/s)	1
		Low orbit satellite speed measurement accuracy (m/s)	0.1
Short-term stability of high orbit satellite frequency source (time stability)	1.00E-09
		Short-term stability of low orbit satellite frequency source (time stability)	1.00E-09
High orbit satellite sampling frequency (MHz)	56
		Low orbit satellite sampling frequency (MHz)	500
Calibration signal frequency (MHz)	280
		Target signal frequency (MHz)	300
Uplink Doppler shift error (Hz)	0.2
		Frequency error (Hz) within the accumulated time of calibration	2.2
Digital sampling channel relative frequency drift error (Hz)	0.4
		Sampling frequency relative drift error (Hz)	0.5
Ground frequency difference estimation error (Hz)	1.0
		Frequency reference accuracy (Hz)	2.5

Let the frequency difference error in the accumulated time during positioning be 2.2Hz, the frequency difference estimation error of the target signal be 1.0Hz, and the total error of the frequency difference measurement be 3.5Hz, as shown in Table 4.

TABLE 4 Table 4

Frequency reference accuracy (Hz)	2.5
		Frequency difference error (Hz) in accumulated time during positioning	2.2
Signal frequency offset estimation error (Hz)	1
		Total error of frequency difference measurement (Hz)	3.5

After ground calibration, the CEP distribution of the double-star time-frequency difference positioning is shown in fig. 6. As can be seen from fig. 6, the positioning accuracy near the lower point of the low-orbit satellite is better than 2km, and the high-accuracy positioning of the target is realized.

The method for positioning the radiation source by combining multiple satellites belongs to the same technical conception as the method for positioning the radiation source by combining multiple satellites, and the embodiment of the application also provides a device for positioning the radiation source by combining multiple satellites, wherein the multiple satellites have overlapped working frequency bands. Fig. 7 shows a block diagram of an apparatus for multi-satellite joint positioning of radiation sources according to an embodiment of the present application, referring to fig. 7, an apparatus 700 for multi-satellite joint positioning of radiation sources includes: a reference error acquisition unit 710, a radiation source signal receiving unit 720, a digital sampling unit 730, a measured time difference and frequency difference acquisition unit 740, a time difference equation and frequency difference equation establishing unit 750, and a radiation source positioning unit 760. Wherein,,

A reference error acquisition unit 710 for acquiring time reference errors and frequency reference errors of a plurality of satellites;

the radiation source signal receiving unit 720 is configured to receive radiation source signals emitted by the radiation sources through a plurality of satellites and digitally sample the received radiation source signals, obtain sampled radiation source signals, and download the sampled radiation source signals to the ground data processing system, where frequencies of the received radiation source signals are located in an operating frequency band overlapped by the satellites;

the digital sampling unit 730 is configured to digitally sample the received radiation source signals through a plurality of satellites, obtain sampled radiation source signals, and download the sampled radiation source signals to the ground data processing system;

a measured time difference and frequency difference acquiring unit 740, configured to acquire a measured time difference and a measured frequency difference of the sampled radiation source signal at a receiving time;

a time difference equation and frequency difference equation establishing unit 750, configured to establish a time difference equation according to time reference errors of the plurality of satellites and measured time differences of the sampled radiation source signals at the receiving time, and establish a frequency difference equation according to frequency reference errors of the plurality of satellites and measured frequency differences of the sampled radiation source signals at the receiving time;

the radiation source positioning unit 760 is configured to position the radiation source according to the equation of time difference and the equation of frequency difference.

In one embodiment of the present application, the reference error acquisition unit 710 is specifically configured to: transmitting calibration signals through a ground calibration station, and adjusting receiver frequency setting parameters of each satellite so that the frequency of the calibration signals is in a second receiver instantaneous working frequency band, wherein the second receiver instantaneous working frequency band is in an overlapped working frequency band; receiving calibration signals through a plurality of satellites, digitally sampling the calibration signals, obtaining sampled calibration signals, and downloading the sampled calibration signals to a ground data processing system; extracting the measured time difference and the measured frequency difference of the sampled calibration signals, and extracting the real time difference and the real frequency difference of the sampled calibration signals reaching a plurality of satellites; determining time reference errors of the plurality of satellites according to the measured time difference of the sampled calibration signals and the real time difference of the sampled calibration signals reaching the plurality of satellites, and determining frequency reference errors of the plurality of satellites according to the measured frequency difference of the sampled calibration signals, the real frequency difference of the sampled calibration signals reaching the plurality of satellites and the frequency of the sampled calibration signals.

In one embodiment of the present application, the reference error acquisition unit 710 is specifically configured to: determining a ground calibration station, a position vector and a relative speed vector of each satellite in a geocentric fixedly connected system, and the frequency of a calibration signal; extracting the real time difference of the sampled calibration signals reaching a plurality of satellites according to the ground calibration station and the position vector of each satellite in the earth center fixedly connected system; and extracting the actual frequency difference of the sampled calibration signals reaching a plurality of satellites according to the ground calibration station, the position vector and the relative speed vector of each satellite in the earth center fixedly connected system and the frequency of the calibration signals.

In one embodiment of the present application, the equation of time difference and equation of frequency difference establishing unit 740 is specifically configured to: determining a position vector and a relative speed vector of the radiation source, each satellite in the geocentric fastening system, and the frequency of the radiation source signal; correcting the time reference errors of a plurality of satellites according to the frequency reference errors and the time difference between the radiation source signals and the calibration signals, and establishing a time difference equation according to the corrected time reference errors of the plurality of satellites, the measured time difference of the sampled radiation source signals and the position vector of the radiation source and each satellite in the earth center fixedly connected system; correcting the frequency reference error according to the frequency of the radiation source signal, and establishing a frequency difference equation according to the corrected frequency reference error, the measured frequency difference of the sampled radiation source signal, the position vector and the relative speed vector of the radiation source and each satellite in the earth center fixedly connected system and the frequency of the radiation source signal.

In one embodiment of the present application, the radiation source positioning unit 750 is specifically configured to: determining a type of radiation source; if the type of the radiation source is a ground target, establishing a geosphere constraint equation according to the position vector of the radiation source, and realizing the positioning of the radiation source according to the geosphere constraint equation, the time difference equation and the frequency difference equation; if the type of the radiation source is a non-ground target, the radiation source is positioned directly through a time difference equation and a frequency difference equation.

In one embodiment of the present application, the apparatus further comprises: and the receiver channelized sampling parameter setting unit is used for setting the same receiver channelized sampling parameters on a plurality of satellites as those of the calibration time.

In one embodiment of the present application, the apparatus further comprises: the precision analysis unit is used for carrying out precision analysis on the time reference errors and the frequency reference errors of the plurality of satellites; a measurement total error calculation unit for calculating a time difference measurement total error according to the accuracy analysis result of the time reference error and calculating a frequency difference measurement total error according to the accuracy analysis result of the frequency reference error; the total time difference measurement error is the sum of the time reference residual error, the time difference error in the accumulated time during positioning and the time difference estimation error, and the total frequency difference measurement error is the sum of the frequency reference residual error, the frequency difference error in the accumulated time during positioning and the frequency difference estimation error of the radiation source signal; and the precision evaluation unit is used for evaluating the precision of the positioning result of the radiation source according to the total time difference measurement error and the total frequency difference measurement error.

It should be noted that:

fig. 8 illustrates a schematic structure of an electronic device. Referring to fig. 8, at a hardware level, the electronic device includes a memory and a processor, and optionally includes an interface module, a communication module, and the like. The Memory may include a Memory, such as a Random-Access Memory (RAM), and may also include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory, and the like. Of course, the electronic device may also include hardware required for other services.

The processor, interface module, communication module, and memory may be interconnected by an internal bus, which may be an ISA (Industry Standard Architecture ) bus, a PCI (Peripheral Component Interconnect, peripheral component interconnect standard) bus, or an EISA (Extended Industry Standard Architecture ) bus, among others. The buses may be divided into address buses, data buses, control buses, etc. For ease of illustration, only one bi-directional arrow is shown in FIG. 8, but not only one bus or type of bus.

And a memory for storing computer executable instructions. The memory provides computer-executable instructions to the processor via the internal bus.

A processor executing computer executable instructions stored in the memory and specifically configured to perform the following operations:

acquiring time reference errors and frequency reference errors of a plurality of satellites;

receiving radiation source signals emitted by the radiation sources through a plurality of satellites, and adjusting receiver frequency setting parameters of each satellite so that the frequency of the radiation source signals is in a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is in an overlapping working frequency band of the satellites;

acquiring the measured time difference and the measured frequency difference of the sampled radiation source signal at the receiving moment;

and positioning the radiation source through a time difference equation and a frequency difference equation.

The functions performed by the apparatus for multi-satellite joint positioning of radiation sources disclosed in the embodiment of fig. 7 of the present application may be implemented in or by a processor. The processor may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or by instructions in the form of software. The processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), etc.; but also digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware, in a decoded processor, or in a combination of hardware and software modules in a decoded processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method.

The electronic device may further execute the steps executed by the method for positioning the radiation source by combining multiple satellites in fig. 1, and implement the functions of the embodiment shown in fig. 1, which are not described herein.

The embodiments of the present application also provide a computer readable storage medium storing one or more programs that, when executed by a processor, implement the aforementioned method for multi-satellite joint positioning of radiation sources, and are specifically configured to perform:

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) containing computer-usable program code.

The present application is described in terms of flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of computer-readable media.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.

It should also be noted that 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 one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.

Claims

1. A method of multi-satellite joint positioning of a radiation source, wherein a plurality of satellites have overlapping operating frequency bands, the method comprising:

receiving radiation source signals emitted by the radiation sources through the satellites at a first moment, and adjusting receiver frequency setting parameters of the satellites so that the frequency of the radiation source signals is in a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is in an overlapping working frequency band of the satellites;

positioning the radiation source through the time difference equation and the frequency difference equation;

the acquiring the time reference error and the frequency reference error of the plurality of satellites includes:

transmitting calibration signals through a ground calibration station at a second moment, and adjusting receiver frequency setting parameters of each satellite so as to enable the frequency of the calibration signals to be in a second receiver instantaneous working frequency band, wherein the second receiver instantaneous working frequency band is positioned in the overlapped working frequency band; the first moment is different from the second moment, the first receiver instantaneous operating frequency band and the second receiver instantaneous operating frequency band are mutually independent, and the first receiver instantaneous operating frequency band and the second receiver instantaneous operating frequency band are the same or different;

Receiving the calibration signals through a plurality of satellites, digitally sampling the calibration signals, obtaining sampled calibration signals, and downloading the sampled calibration signals to a ground data processing system;

extracting the measured time difference and the measured frequency difference of the sampled calibration signals, and extracting the real time difference and the real frequency difference of the sampled calibration signals reaching the plurality of satellites;

determining time reference errors of the plurality of satellites according to the measured time difference of the sampled calibration signals and the real time difference of the sampled calibration signals reaching the plurality of satellites, and determining frequency reference errors of the plurality of satellites according to the measured frequency difference of the sampled calibration signals, the real frequency difference of the sampled calibration signals reaching the plurality of satellites and the frequency of the sampled calibration signals so as to realize high-precision positioning of all radiation sources in the whole working frequency band where the plurality of satellites are overlapped in a certain duration time span through single calibration;

the radiation source signals transmitted by the plurality of satellite receiving radiation sources include:

setting the same receiver channelized sampling parameters on a plurality of satellites as those of the standard time;

The time reference error and the frequency reference error are expressed as:

Δt _ij ＝t _ij ^bt -t _ij ^bm ，

wherein Δt is _ij And Deltaref _ij Time reference error and frequency reference error of uncorrelated multi-star positioning system established based on calibration signal respectively, t _ij ^bt And f _ij ^bt Respectively, the calibration signals arrive at satellite S _i 、S _j Real time difference and real frequency difference, t _ij ^bm And f _ij ^bm Respectively, the calibration signals arrive at satellite S _i 、S _j And the measurement time difference and the measurement frequency difference f _b Calibrating the frequency of the signal;

the radiation source signal reaching satellite S _i 、S _j Is the true time difference t of (2) _ij ^pt And true frequency difference f _ij ^pt ：

t _ij ^pt ＝t _ij ^pm +Δt _ij -Δref _ij (t ₂ -t ₁ )+ξ _ij

f _ij ^pt ＝f _ij ^pm +Δref _ij ·f _p +ε _ij

Wherein t is _ij ^pm And f _ij ^pm The sampled radiation source signals respectively extracted for the ground data processing system reach the satellite S _i 、S _j And the measured time difference and the measured frequency difference, Δref _ij (t ₂ -t ₁ ) To be guided by frequency source accuracyTime scale drift correction value f of sampled data _p Is the frequency of the radiation source signal, ζ _ij 、ε _ij Respectively after passing the calibration, S _i 、S _j A time reference residual error and a frequency reference residual error.

2. The method of claim 1, wherein the extracting the true time difference and true frequency difference of the sampled calibration signal to the plurality of satellites comprises:

determining the position vector and the relative speed vector of the ground calibration station and each satellite in the earth center fixedly connected system, and the frequency of a calibration signal;

Extracting the real time difference of the sampled calibration signals reaching the plurality of satellites according to the ground calibration station and the position vector of each satellite in the earth center fixedly connected system;

and extracting the actual frequency difference of the sampled calibration signals reaching the plurality of satellites according to the ground calibration station, the position vector and the relative speed vector of each satellite in the earth center fixedly connected system and the frequency of the calibration signals.

3. The method of claim 1, wherein the establishing a time difference equation based on the time reference errors of the plurality of satellites and the measured time differences of the sampled radiation source signals at the time of reception, and the establishing a frequency difference equation based on the frequency reference errors of the plurality of satellites and the measured frequency differences of the sampled radiation source signals at the time of reception comprises:

determining a position vector and a relative speed vector of the radiation source, each satellite in the geocentric fastening system, and the frequency of the radiation source signal;

correcting the time reference errors of the satellites according to the frequency reference errors and the time difference between the radiation source signals and the calibration signals, and establishing the time difference equation according to the corrected time reference errors of the satellites, the measured time difference of the sampled radiation source signals and the position vector of the radiation source and each satellite in the earth center fixedly connected system;

Correcting the frequency reference error according to the frequency of the radiation source signal, and establishing the frequency difference equation according to the corrected frequency reference error, the measured frequency difference of the sampled radiation source signal, the position vector and the relative velocity vector of the radiation source and each satellite in the earth center fixedly connected system and the frequency of the radiation source signal.

4. The method of claim 1, wherein said effecting positioning of said radiation source by said equation of time difference and said equation of frequency difference comprises:

determining a type of the radiation source;

if the type of the radiation source is a ground target, establishing a geosphere constraint equation according to a position vector of the radiation source, and realizing positioning of the radiation source according to the earth surface constraint equation, the time difference equation and the frequency difference equation;

if the type of the radiation source is a non-ground target, the radiation source is positioned directly through the time difference equation and the frequency difference equation.

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

performing accuracy analysis on time reference errors and frequency reference errors of the plurality of satellites;

Calculating the total error of the time difference measurement according to the accuracy analysis result of the time reference error, and calculating the total error of the frequency difference measurement according to the accuracy analysis result of the frequency reference error;

the total time difference measurement error is the sum of a time reference residual error, a time difference error in the accumulated time during positioning and a time difference estimation error, and the total frequency difference measurement error is the sum of a frequency reference residual error, a frequency difference error in the accumulated time during positioning and a frequency difference estimation error of a radiation source signal;

and carrying out precision evaluation on the positioning result of the radiation source according to the time difference measurement total error and the frequency difference measurement total error.

6. An apparatus for multiple satellite joint positioning of a radiation source, wherein a plurality of satellites have overlapping operating frequency bands, the apparatus comprising:

the radiation source signal receiving unit is used for receiving radiation source signals emitted by the radiation sources through the satellites at a first moment, and adjusting receiver frequency setting parameters of the satellites so that the frequency of the radiation source signals is in a first receiver instantaneous working frequency range, wherein the first receiver instantaneous working frequency range is in an overlapping working frequency range of the satellites;

the radiation source positioning unit is used for positioning the radiation source through the time difference equation and the frequency difference equation;

the reference error acquisition unit is specifically configured to:

the radiation source signal receiving unit is specifically configured to:

the time reference error and the frequency reference error are expressed as:

Δt _ij ＝t _ij ^bt -t _ij ^bm ，

Wherein Δt is _ij And Deltaref _ij Time reference error and frequency reference error of uncorrelated multi-star positioning system established based on calibration signal respectively, t _ij ^bt And f _ij ^bt Respectively calibrating signalsArrive at satellite S _i 、S _j Real time difference and real frequency difference, t _ij ^bm And f _ij ^bm Respectively, the calibration signals arrive at satellite S _i 、S _j And the measurement time difference and the measurement frequency difference f _b Calibrating the frequency of the signal;

t _ij ^pt ＝t _ij ^pm +Δt _ij -Δref _ij (t ₂ -t ₁ )+ξ _ij

f _ij ^pt ＝f _ij ^pm +Δref _ij ·f _p +ε _ij

Wherein t is _ij ^pm And f _ij ^pm The sampled radiation source signals respectively extracted for the ground data processing system reach the satellite S _i 、S _j And the measured time difference and the measured frequency difference, Δref _ij (t ₂ -t ₁ ) For correction of time scale drift of sampled data due to frequency source accuracy, f _p Is the frequency of the radiation source signal, ζ _ij 、ε _ij Respectively after passing the calibration, S _i 、S _j A time reference residual error and a frequency reference residual error.

7. An electronic device, comprising: a processor, a memory storing computer executable instructions,

the executable instructions, when executed by the processor, implement the method of multi-satellite joint positioning radiation source of any of claims 1-5.