CN113433573A

CN113433573A - Method and device for multi-satellite combined positioning of radiation source and electronic equipment

Info

Publication number: CN113433573A
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: 2021-09-24
Anticipated expiration: 2041-06-03
Also published as: CN113433573B

Abstract

The application discloses a method and a device for jointly positioning a radiation source by multiple satellites and electronic equipment. The method for jointly positioning the radiation source by the multiple satellites aims at a non-relevant multi-satellite system with overlapped working frequency bands, and firstly, time reference errors and frequency reference errors obtained by the multiple satellites through calibration are obtained; and then, receiving a radiation source signal emitted by a radiation source within a certain time span, carrying out digital sampling on 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 applying the time reference error and the frequency reference error, and finally, realizing high-precision positioning on the radiation source by solving the time difference equation and the frequency difference equation. The method and the device solve the problem of non-relevant multi-satellite combined high-precision positioning, can realize high-precision positioning of all interested targets in the overlapped working frequency band in a certain duration span through single calibration, and have wide application prospect.

Description

Method and device for multi-satellite combined positioning of radiation source and electronic equipment

Technical Field

The application relates to the technical field of radio positioning, in particular to a method and a device for jointly positioning a radiation source by multiple satellites and electronic equipment.

Background

A multi-time difference of arrival (TDOA) or time frequency difference (TDOA/FDOA) positioning system is one of the means for obtaining high-precision positioning of a radiation source. Generally, such a positioning system is designed from the beginning and considered in terms of multi-satellite formation, and a complex inter-satellite link and an ultra-high stable rubidium clock are arranged between satellites, so that a time reference and a frequency reference of the positioning system are realized through the inter-satellite link.

However, the application of the multi-satellite positioning technology is not considered at the beginning of satellite design with more practical situations, and only the single-satellite positioning technology is adopted, so that the positioning accuracy is lower, and the combat requirement cannot be met; or under the condition that one or more satellites of some multi-satellite positioning systems fail, multi-satellite positioning can not be realized.

Disclosure of Invention

In view of this, a main object of the present application is to provide a method, an apparatus and an electronic device for jointly positioning a radiation source by multiple satellites, so as to solve the technical problem of poor positioning accuracy of a radiation source positioning method in the prior art.

According to a first aspect of the present application, there is provided a method for jointly positioning a radiation source by multiple satellites, the multiple 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 radiation sources through the plurality of satellites, and adjusting receiver frequency setting parameters of each satellite so as to enable the frequency of the radiation source signals to be within a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is located in a working frequency band overlapped by the plurality of satellites;

carrying out digital sampling on 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 measurement time difference and the measurement frequency difference of the sampled radiation source signal at the receiving moment;

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

and realizing the positioning of 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 jointly positioning a radiation source by multiple satellites, the multiple satellites having overlapping operating frequency bands, the apparatus comprising:

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

a radiation source signal receiving unit, configured to receive radiation source signals emitted by radiation sources through the multiple satellites, and adjust receiver set-frequency parameters of each satellite, so that a frequency of the radiation source signals is within a first receiver instantaneous operating frequency band, where the first receiver instantaneous operating frequency band is within an overlapping operating frequency band of the multiple satellites;

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

a measurement time difference and measurement frequency difference obtaining unit, configured to obtain a measurement time difference and a measurement frequency difference of the sampled radiation source signal at a receiving time;

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

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

In accordance with 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 a radiation source.

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 localization of a radiation source.

The beneficial effect of this application is: the method for jointly positioning the radiation source by the multiple satellites aims at a non-relevant multi-satellite system which does not have time reference and frequency reference and has overlapped working frequency bands, and firstly, time reference errors and frequency reference errors obtained by the multiple satellites through calibration are obtained; and then within a certain time span, adjusting a satellite receiver frequency setting parameter according to the radiation source frequency to enable the frequency of the radiation source signal to be within the instantaneous working frequency band of the first receiver, carrying out digital sampling on 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 high-precision positioning of the radiation source based on the time difference or the time frequency difference. The embodiment of the application solves the problem of non-relevant multi-satellite combined high-precision positioning, can bring a plurality of non-relevant satellites into a positioning system, and can realize high-precision positioning of all interested targets in a multi-satellite overlapped working frequency band in a certain duration span after single calibration, so that the method has a 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 refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic flow chart of a method for jointly positioning a radiation source with multiple satellites according to one embodiment of the present application;

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

FIG. 3 is a schematic diagram of a positional relationship of a satellite, a ground calibration station, and a radiation source under a ground-center fastening system 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 an embodiment of the present application;

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

FIG. 6 is a diagram of a two-satellite time difference positioning CEP distribution after ground calibration according to an embodiment of the present application;

FIG. 7 is a block diagram of an apparatus for multi-satellite joint positioning of a radiation source according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of an electronic device in 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 schematic flowchart illustrating a method for jointly positioning a radiation source by multiple satellites according to an embodiment of the present application, and referring to fig. 1, a plurality of satellites of the embodiment of the present application have overlapping operating frequency bands, and the method for jointly positioning a radiation source by multiple satellites of the embodiment of the present application includes the following steps S110 to S160:

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

step S120, a radiation source signal emitted by a radiation source is received through a plurality of satellites, and a receiver frequency setting parameter of each satellite is adjusted, so that the frequency of the radiation source signal is in a first receiver instantaneous working frequency range, wherein the first receiver instantaneous working frequency range is in a working frequency range overlapped by the plurality of satellites;

step S130, carrying out digital sampling on 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;

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

step S150, establishing a time difference equation according to the time reference errors of the plurality of satellites and the measurement time difference of the sampled radiation source signals at the receiving moment, and establishing a frequency difference equation according to the frequency reference errors of the plurality of satellites and the measurement frequency difference of the sampled radiation source signals at the receiving moment;

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

The method for jointly positioning the radiation source by the multiple satellites aims at a non-relevant multi-satellite system which does not have a time base and a frequency reference and has an overlapped working frequency band, and firstly, time reference errors and frequency reference errors obtained by the multiple satellites through calibration are obtained; and then within a certain time span, adjusting a satellite receiver frequency setting parameter according to the radiation source frequency to enable the frequency of the radiation source signal to be within the instantaneous working frequency band of the first receiver, carrying out digital sampling on 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 high-precision positioning of the radiation source based on the time difference or the time frequency difference.

The embodiment of the application solves the problem of non-relevant multi-satellite combined high-precision positioning, can bring a plurality of non-relevant satellites into a positioning system, and can realize high-precision positioning of all interested targets in a multi-satellite overlapped working frequency band in a certain duration span after single calibration because digital sampling is completed on the satellites, so the method has a wide application prospect in the aspect of multi-satellite high-precision positioning.

It should be noted that the number of satellites aimed at by the multi-satellite joint positioning radiation source method in the embodiment of the present application may be two, or may be any number of two or more, for example, the multi-satellite joint positioning radiation source method provided by the present application may be applied to a non-correlated two-satellite/three-satellite positioning system, and high-precision positioning of a ground stationary or slow target may be achieved by a two-satellite time-frequency difference positioning technique/a three-satellite time difference positioning technique; or the method can also be applied to an uncorrelated four-satellite positioning system, and can realize high-precision positioning of an aerial target through a four-satellite time difference positioning technology.

For the convenience of understanding the embodiments of the present application, the following embodiments are described by taking a positioning system composed of two uncorrelated satellites as an example.

In one embodiment of the present application, acquiring time reference errors and frequency reference errors for a plurality of satellites comprises: transmitting calibration signals through a ground calibration station, and adjusting receiver frequency setting parameters of each satellite so as to enable the frequency of the calibration signals to be within the instantaneous working frequency band of a second receiver, wherein the instantaneous working frequency band of the second receiver is within the overlapped working frequency band; receiving calibration signals through a plurality of satellites and carrying out digital sampling on the calibration signals to obtain sampled calibration signals and downloading the sampled calibration signals to a ground data processing system; extracting the measurement time difference and the measurement 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; and determining the time reference errors of the plurality of satellites according to the measurement time difference of the sampled calibration signal and the real time difference of the sampled calibration signal reaching the plurality of satellites, and determining the frequency reference errors of the plurality of satellites according to the measurement frequency difference of the sampled calibration signal, the real frequency difference of the sampled calibration signal reaching the plurality of satellites and the frequency of the sampled calibration signal.

As shown in fig. 2, a schematic structural diagram of a two-satellite frequency measurement positioning system according to an embodiment of the present application is provided. The double-satellite 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 above two-satellite frequency measurement positioning system, in the embodiment of the present application, when acquiring the time reference error and the frequency reference error of two satellites, the satellite i and the satellite j may be used to receive the calibration signals transmitted by the ground calibration station, respectively, and the satellite i and the satellite j may be regarded as having the overlapped working frequency band M_fOf a communication satellite with digital sampling, a second receiver of satellite i and of satellite jThe instantaneous operating band needs to be located in the overlapping operating band M of the two satellites_fAnd the frequency of the calibration signal transmitted by the ground calibration station also needs to be located in the instantaneous working frequency band of the second receiver, so that the transmitted calibration signal can be simultaneously received by the satellite i and the satellite j.

It should be noted that the second receiver instantaneous operating frequency band and the first receiver instantaneous operating frequency band of the above embodiments 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 at N_f1(N_f1∈M_f)。

Because the working frequency bands of the calibration signal and the radiation source signal are mutually independent, when the radiation source signal is transmitted, the receiver frequency setting parameter on the satellite can be flexibly adjusted, as long as the frequency of the radiation source signal is in the instantaneous working frequency band of the first receiver, and thus the radiation source signal in the whole working frequency band can be positioned by single calibration.

Then, the satellite i and the satellite j respectively carry out digital sampling on the calibration signals, then the sampled calibration signals are downloaded to a ground data processing system to obtain the sampled calibration signals, 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-satellite positioning system according to the measurement 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-satellite positioning system according to the measurement 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 difference and the real frequency difference of the sampled calibration signal reaching a plurality of satellites includes: determining a ground calibration station, a position vector and a relative velocity vector of each satellite in a geocentric fixed connection 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 position vectors of the ground calibration station and each satellite in the geocentric fixed connection; and extracting the real frequency difference of the sampled calibration signals reaching a plurality of satellites according to the ground calibration station, the position vector and the relative velocity vector of each satellite in the geocentric fixed connection system and the frequency of the calibration signals.

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

When the real time difference and the real 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 used for determining t₁The ground calibration station (B) is fixedly connected with the earth center (S)_e) Lower position vector r_bAnd a relative velocity vector v_bSatellite i (S)_i) Position vector r of_i1And a relative velocity vector v_i1Satellite j (S)_j) Position vector r of_j1And a relative velocity vector v_j1And the frequency f of the calibration signal_bThen the calibration signal arrives at S_i、S_jTrue time difference t_ij ^btAnd true frequency difference f_ij ^btCan be represented by formula (1) and formula (2), respectively:

then, S_i、S_jThe received calibration signal is digitally sampled and then is downloaded to a ground data processing system, and the ground data processing system extracts the calibration signal to S from the sampled calibration signal by a direct or indirect method_i、S_jMeasured time difference t_ij ^bmAnd measuring the frequency difference f_ij ^bm. ThenTime reference error delta t of the uncorrelated multi-satellite positioning system established based on calibration signals_ijAnd frequency reference error Δ ref_ijCan be expressed as formula (3) and formula (4), respectively:

Δt_ij＝t_ij ^bt-t_ij ^bm， (3)

the calibration signal transmitted by the ground calibration station is sampled on two satellites and then is downloaded to the ground data processing system, so that the frequency of the calibration signal directly influences the calculation of the real frequency difference and the measured frequency difference, and the frequency reference error delta ref is obtained_ijMay further take into account the frequency f of the calibration signal_bHere, the expression may be performed in a normalized manner.

In one embodiment of the present application, the establishing a time difference equation according to the time reference errors of the plurality of satellites and the measured time differences of the sampled radiation source signals at the receiving time, and the establishing a frequency difference equation according to the frequency reference errors of the plurality of satellites and the measured frequency differences of the sampled radiation source signals at the receiving time comprise: determining a radiation source, a position vector and a relative velocity vector of each satellite in the earth-centered solid system, and the frequency of a radiation source signal; correcting the time reference errors of the plurality of satellites according to the frequency reference errors and the time difference of the emission of 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 measurement time difference of the sampled radiation source signals and the position vectors of the radiation source and each satellite in the earth-centered solid connection; and 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 radiation source, the position vector and the relative velocity vector of each satellite in the geocentric fixed connection system and the frequency of the radiation source signal.

Time reference error Δ t obtained based on the above embodiment_ijSum frequencyReference error Δ ref_ijThe time difference equation and the frequency difference equation of the non-correlation multi-satellite positioning system can be established by taking the time difference equation and the frequency difference equation as compensation values and considering certain correction, and after the time difference equation and the frequency difference equation are obtained, multi-satellite positioning can be carried out on the radiation source.

Specifically, at t₂At the moment, the radiation source signal is S_i、S_jReceiving, the receiver on the satellite carries out digital sampling on 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 S_i、S_jMeasured time difference t_ij ^pmAnd measuring the frequency difference f_ij ^pm. Then, the time reference error Δ t is compensated_ijAnd frequency reference error Δ ref_ijAnd after a certain correction value is considered, the arrival satellite S of the radiation source signal can be obtained_i、S_jTrue time difference t_ij ^ptAnd true frequency difference f_ij ^ptAs shown in the following formulas (5) and (6):

t_ij ^pt＝t_ij ^pm+Δt_ij-Δref_ij(t₂-t₁)+ξ_ij， (5)

f_ij ^pt＝f_ij ^pm+Δref_ij·f_p+ε_ij， (6)

wherein, Δ ref_ij(t₂-t₁) Correction value for time scale drift of sampled data caused by frequency source accuracy, f_pIs the frequency, xi, of the radiation source signal_ij、ε_ijRespectively after passing calibration, S_i、S_jThe time reference residual error and the frequency reference residual error between the two are random white gaussian noise, the variance of which becomes larger with the time lapse and can be regarded as a constant value within a certain time span, and the time span depends on the tolerable positioning accuracy.

At t₂At the moment, let the position vector and the relative velocity vector of the radiation source in the earth-centered solid-fixed system be r_p、v_p，S_iThe position vector and the relative velocity vector in the earth-centered solid-connected system are r_i2、v_i2，S_jThe position vector and the relative velocity vector in the earth-centered solid-connected system are r_j2、v_j2Frequency f of radiation source signal_pThen, the equation of time difference and the equation of frequency difference including the position of the radiation source can be expressed as equation (7) and equation (8), respectively:

by combining the above equations (7) and (8), the position vector r of the radiation source can be obtained_pAnd the relative velocity vectors are respectively v_pThereby 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 higher stability so as to have negligible influence on the time scale of the sampled data within a certain time span.

Further, t of the above embodiment₁Time t and₂the time is not required to be equal, namely non-real time, so that compared with a method for realizing multi-satellite positioning by carrying out real-time calibration through an associated signal, the method does not need a calibration signal and a radiation source signal to be simultaneously digitally sampled by a receiver on a satellite, and therefore the method has higher flexibility and stronger concealment in application.

In one embodiment of the present application, the positioning of the radiation source by the time difference equation and the frequency difference equation comprises: determining the type of radiation source; if the type of the radiation source is a ground target, establishing a terrestrial surface constraint equation according to the position vector of the radiation source, and realizing the positioning of the radiation source according to the terrestrial surface constraint equation, the time difference equation and the frequency difference equation; and 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 scenarios, there may be two types of radiation sources, one is a ground radiation source, and the other is a non-ground radiation source, and if it is determined from the prior information that the radiation source currently to be positioned is a ground radiation source, the position of the radiation source also obeys a terrestrial spherical constraint, as shown in the following formula (9):

wherein, [ x ]_p,y_p,z_p]^T＝r_pAnd a and e are respectively the semimajor axis and the oblateness of the earth.

Equations (7), (8) and (9) are simultaneously established, and high-precision positioning of the radiation source can be realized by solving the equation system.

In one embodiment of the present application, transmitting the calibration signal via the ground calibration station comprises: setting the receiver channelized sampling parameters on a plurality of satellites to be the same as the receiver channelized sampling parameters in calibration.

The receiver channelization sampling parameters on the satellite in the embodiment of the application need to be consistent with the receiver channelization sampling parameters in calibration, so that the time reference error calculated in the embodiment can be applied.

In addition, in engineering application, data after digital sampling can be stored in a satellite, so that a ground receiving station is not required to be within a visual range of the satellite all the time, the data after digital sampling can be downloaded to the ground in a non-real-time manner for receiving, and the application range of the method for jointly positioning the radiation source by multiple satellites in the embodiment of the application is greatly expanded.

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

In order to further measure the positioning accuracy of the multi-satellite combined positioning radiation source method of 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.

As shown in fig. 4, a block diagram of a calibration flow based on non-real-time digital sampling according to an embodiment of the present application is provided. Calibration signal transmitted by ground calibration station is received by satellite S_iAnd S_jAfter receiving, carrying out digital sampling on the signals and downloading the signals to a ground data processing system, wherein the ground data processing system respectively reaches S through calibration signals_iAnd S_jAnd the time difference and the frequency difference are combined with the positioning precision of the satellite platform to obtain the time reference precision and the frequency reference precision of the calibrated non-correlation multi-satellite positioning system.

The specific calculation process is as follows:

(1) post calibration time reference accuracy analysis

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

(a) uplink path delay error: the distance between the ground calibration station and the satellite causes that the position of the ground calibration station is fixed, the error is mainly determined by the position error of the satellite, and the position error of the satellite changes along with the time, so the error cannot be eliminated. Assuming that the orbit determination precision of two satellites is sigma_si、σ_sjThe delay error between two stars due to path propagation can be expressed as

(b) And (3) calibrating the time difference error in the accumulated time: due to relative motion between satellite platforms, the value is small when the orbits are close, and the value is large when the orbit difference is large. This value appears as an indeterminate random error, which can be expressed as σ_rt；

(c) Satellite up-sampling time point error: the data sampling time point of the receiving channel and the data packing time stamp can not be completely aligned, certain deviation exists, and the deviation can be represented by counting point errors of an AD counter. Suppose that two satellites have sampling frequencies f_si、f_sjAnd the error of the counting point of the on-satellite AD counter is N (2 can be taken), the caused delay error can be expressed as

(d) On-satellite AD counter count drift error: the AD counter can mark time, and the counting error of the AD counter is mainly linear deviation and drift error, wherein the linear deviation changes along with the time, and the drift error randomly walks along with the time. After ground calibration, the linear deviation can be compensated, the drift error can not be compensated, and the short-term stability of the frequency source and the calibration time interval are related. Suppose that the short-term stability of the frequency sources of two satellites is respectively sigma_fi、σ_fjThe maximum drift error in the calibration time interval t is about

(c) Ground time difference estimation error: time error sigma mainly estimated for time-frequency difference_ct。

In summary, based on the calibration signal, the time reference residual error, i.e. the time reference precision, after calibration by non-real-time digital sampling 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/channelization frequency error (fixed deviation) can be calibrated, and meanwhile, the uplink doppler shift error, the frequency difference error in the accumulated time and the ground processing error are introduced, so that the frequency reference residual error after calibration mainly comprises:

(a) uplink doppler shift error: the method is caused by the projection of the relative motion speed of the ground calibration station and the satellite on a relative position vector, the position of the ground calibration station is fixed, the error is mainly determined by the position and speed error of the satellite, and the error cannot be eliminated due to the change of the position and speed error of the satellite along with time, and is represented as an uncertain random error. Suppose that the speed measurement errors of two satellites are respectively sigma_vi、σ_vjCalibration source uplink frequency is f_bThen the maximum doppler shift error can be expressed as

(

As a satellite S_iTo satellite S at the edge of the antenna beam_iMaximum included angle with the center of the earth) of the ground,

(

As a satellite S_jTo satellite S at the edge of the antenna beam_jThe maximum included angle with the line connecting the geocentric), the uplink Doppler shift error sigma between the two stars is calculated_udij can be expressed as:

(b) for calibrating cumulative timeFrequency difference error: due to relative motion between satellite platforms, the value is small when the orbits are close, and the value is large when the orbit difference is large. This value appears as an indeterminate random error, which can be expressed as σ_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/channelization sampling part, is mainly determined by satellite payload frequency source error and channel characteristics, and is divided into a fixed deviation and a short-term drift error. After ground calibration, the fixed deviation can be compensated, the short-term drift error can not be compensated, and the short-term drift error can not be compensated and can change along with time and is related to the short-term stability of the signal frequency and the frequency source (calibration intervals need to be considered, different drift errors are obtained corresponding to different stabilities).

Suppose that the frequency stability of two satellites is sigma_fi、σ_fjFrequency of radiation source signal f_pThen the maximum relative frequency drift error of the digital sampling channel obtained by calibration can be expressed as

(d) Sampling frequency relative drift error: the sampling frequency relative error comprises a fixed frequency deviation and a drift error, wherein the fixed frequency deviation is relatively constant, and the drift error is changed along with time. After ground calibration, the fixed frequency offset can be compensated, the drift error can not be compensated, and the fixed frequency offset is related to the short-term stability of the frequency source (calibration intervals need to be considered, different drift errors are obtained corresponding to different stabilities). Suppose that the short-term stability of the frequency sources of two satellites is respectively sigma_fi、σ_fjSampling frequencies of f_si、f_sjThen the maximum relative drift error of the sampling frequency obtained by calibration can be expressed as

(e) And (3) ground calibration signal frequency difference estimation error: frequency error sigma mainly for time-frequency difference estimation of calibration signal_cf。

In summary, 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 the above equation (12), the frequency reference accuracy is related to the stability of the frequency source, which is related to the time span (the stability is worse the longer the time span is), so the reference frequency accuracy changes with time, and after calibration by the ground calibration, the reference frequency accuracy can be regarded as a constant value in a certain time span.

Based on the embodiment, the time reference precision and the frequency reference precision of the positioning system are obtained through ground calibration. Then, the total time difference measurement error of the non-correlation multi-satellite combined high-precision positioning system after calibration based on non-real-time digital sampling can be expressed as the sum of time reference precision, time difference error in accumulated time during positioning and time difference estimation error; the total error of the frequency offset measurement can be expressed as the sum of the frequency reference precision, the frequency offset error in the accumulated time during 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, the satellite positioning accuracy and the positioning equation set, CEP (Circular Error basic, Circular probability Error) distribution of the system positioning accuracy can be obtained, and detailed derivation is not described in detail in the embodiments of the present application.

In order to verify the positioning effect of the multi-satellite joint positioning radiation source method, the embodiment of the application also provides a positioning precision analysis process of the double-satellite joint positioning radiation source. Firstly, a high-precision positioning system combining the uncorrelated low-orbit satellite and the high-orbit satellite is established, and then the CEP distribution of the positioning system is given.

The low-orbit satellite is in a sun-synchronous orbit with the height of 800km, the beam width of an 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 low-orbit satellite and the high-orbit satellite is shown in fig. 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 collaborative design consideration, there is no frequency reference between them, or the error of the frequency reference is very large (more than tens kHz or hundreds kHz), and meanwhile, the time service modes of the satellite platforms may be different, which will cause the error of the two-star time reference to be also very large (possibly in the range of second), so that the time-frequency difference positioning of the two-star union cannot be performed at all.

Based on this, in order to solve the high-precision positioning of the two-star combination, ground calibration is necessary. As shown in fig. 5, a ground calibration station (BJZ) and a target radiation source (Ship) exist on the ground, the low-orbit satellite and the high-orbit satellite firstly share the calibration station, calibration signals (with the frequency of 280MHz) are transmitted by the calibration station, the low-orbit satellite and the high-orbit satellite simultaneously carry out digital sampling on the calibration signals and then download to the ground, and the ground data processing system carries out system calibration. After calibration, the fixed error can be eliminated, and finally, the time reference precision and the frequency reference precision which can be obtained are calculated according to the formulas (10) and (12) respectively.

Table 1 shows initial conditions and final results of time reference accuracy calculation, and the calibration time interval is 1 hour, so that the two-star time reference accuracy after calibration is better than the calculated value within 1 hour, and time calibration needs to be performed again after the time span is more than 1 hour.

TABLE 1

High orbit satellite positioning precision (m)	500
		Low orbit satellite positioning precision (m)	5
High orbit satellite sampling frequency (MHz)	56
		Low orbit satellite sampling frequency (MHz)	500
Error of counting point of AD counter	2
		High orbit satellite frequency source stability (Steady second)	1.00E-10
Low earth orbit satellite frequency source stability (Steady second)	1.00E-10
		Calibration time interval t(s)	3600
Uplink path delay error (ns)	1667
		Timing difference error (ns) in the accumulated time of calibration	500
On-satellite sampling time point error (ns)	36
		Satellite AD counter count drift error (ns)	170
Ground time difference estimation error (ns)	150
		Time-based residual error (ns)	1755

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

TABLE 2

Time-based residual error (ns)	1775
		Time difference error (ns) in accumulated time of positioning time	1000
Signal time difference estimation error (ns)	600
		Time difference measurement total error (ns)	2124

Table 3 shows initial conditions and final results of frequency reference accuracy calculation, and in table 3, the satellite frequency source stability and the ground frequency source stability both show time stability accuracy, so that the calibrated two-satellite frequency reference accuracy is better than the calculated value within 1 hour, and the frequency calibration needs to be performed again after the time span is greater than 1 hour.

TABLE 3

High orbit satellite speed measuring precision (m/s)	1
		Low earth orbit satellite speed measuring precision (m/s)	0.1
Short-time stability (instable) of high-orbit satellite frequency source	1.00E-09
		Low earth orbit satellite frequency source short time stability (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
Up Doppler shift error (Hz)	0.2
		Frequency error (Hz) in time accumulation	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

The frequency difference error in the accumulated time during positioning is made to be 2.2Hz, the frequency difference estimation error of the target signal is made to be 1.0Hz, and the total error of the frequency difference measurement is made to be 3.5Hz, as shown in table 4.

TABLE 4

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

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

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

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

a radiation source signal receiving unit 720, configured to receive radiation source signals emitted by radiation sources through multiple satellites, perform digital sampling on the received radiation source signals, obtain sampled radiation source signals, and download the sampled radiation source signals to a ground data processing system, where a frequency of the received radiation source signals is located in an overlapping working frequency band of the multiple satellites;

the digital sampling unit 730 is used for digitally sampling the received radiation source signals through a plurality of satellites to obtain the sampled radiation source signals and downloading the sampled radiation source signals to the ground data processing system;

a measurement time difference and measurement frequency difference obtaining unit 740, configured to obtain a measurement time difference and a measurement 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 the time reference errors of the multiple satellites and the measurement time differences of the sampled radiation source signals at the receiving time, and establish a frequency difference equation according to the frequency reference errors of the multiple satellites and the measurement frequency differences of the sampled radiation source signals at the receiving time;

and the radiation source positioning unit 760 is used for realizing the positioning of the radiation source through the time difference equation and the frequency difference equation.

In an embodiment of the present application, the reference error obtaining unit 710 is specifically configured to: transmitting calibration signals through a ground calibration station, and adjusting receiver frequency setting parameters of each satellite so as to enable the frequency of the calibration signals to be within the instantaneous working frequency band of a second receiver, wherein the instantaneous working frequency band of the second receiver is within the overlapped working frequency band; receiving calibration signals through a plurality of satellites and carrying out digital sampling on the calibration signals to obtain sampled calibration signals and downloading the sampled calibration signals to a ground data processing system; extracting the measurement time difference and the measurement 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; and determining the time reference errors of the plurality of satellites according to the measurement time difference of the sampled calibration signal and the real time difference of the sampled calibration signal reaching the plurality of satellites, and determining the frequency reference errors of the plurality of satellites according to the measurement frequency difference of the sampled calibration signal, the real frequency difference of the sampled calibration signal reaching the plurality of satellites and the frequency of the sampled calibration signal.

In an embodiment of the present application, the reference error obtaining unit 710 is specifically configured to: determining a ground calibration station, a position vector and a relative velocity vector of each satellite in a geocentric fixed connection 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 position vectors of the ground calibration station and each satellite in the geocentric fixed connection; and extracting the real frequency difference of the sampled calibration signals reaching a plurality of satellites according to the ground calibration station, the position vector and the relative velocity vector of each satellite in the geocentric fixed connection system and the frequency of the calibration signals.

In an embodiment of the present application, the time difference equation and frequency difference equation establishing unit 740 is specifically configured to: determining a radiation source, a position vector and a relative velocity vector of each satellite in the earth-centered solid system, and the frequency of a radiation source signal; correcting the time reference errors of the plurality of satellites according to the frequency reference errors and the time difference of the emission of 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 measurement time difference of the sampled radiation source signals and the position vectors of the radiation source and each satellite in the earth-centered solid connection; and 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 radiation source, the position vector and the relative velocity vector of each satellite in the geocentric fixed connection 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 the type of radiation source; if the type of the radiation source is a ground target, establishing a terrestrial surface constraint equation according to the position vector of the radiation source, and realizing the positioning of the radiation source according to the terrestrial surface constraint equation, the time difference equation and the frequency difference equation; and 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 receiver channelized sampling parameters on the plurality of satellites to be the same as the receiver channelized sampling parameters in calibration.

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; the total error measurement calculating unit is used for calculating a total error of time difference measurement according to the precision analysis result of the time reference error and calculating a total error of frequency difference measurement according to the precision 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 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 accumulated time during positioning and a frequency difference estimation error of a radiation source signal; and the precision evaluation unit is used for carrying out precision evaluation on the positioning result of the radiation source according to the total error of the time difference measurement and the total error of the frequency difference measurement.

It should be noted that:

fig. 8 illustrates a schematic structural diagram of an electronic device. Referring to fig. 8, at a hardware level, the electronic device includes a memory and a processor, and optionally further 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, such as at least one disk Memory. Of course, the electronic device may also include hardware required for other services.

The processor, the interface module, the communication module, and the memory may be connected to each other via an internal bus, which may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 8, but that does not indicate only one bus or one type of bus.

A memory for storing computer executable instructions. The memory provides computer executable instructions to the processor through 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 transmitted by a radiation source through a plurality of satellites, and adjusting receiver set frequency parameters of each satellite so as to enable the frequency of the radiation source signals to be within a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is located within a working frequency band overlapped by the plurality of satellites;

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

The functions performed by the apparatus for jointly positioning multiple radiation sources according to 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 instructions in the form of software. The Processor may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but also Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components. The various methods, steps, and logic blocks disclosed 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 the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in a memory, and a processor reads information in the memory and completes the steps of the method in combination with hardware of the processor.

The electronic device may further perform the steps performed by the method for jointly positioning a radiation source by multiple satellites in fig. 1, and implement the functions of the method for jointly positioning a radiation source by multiple satellites in the embodiment shown in fig. 1, which are not described herein again.

Embodiments of the present application also provide a computer-readable storage medium storing one or more programs which, when executed by a processor, implement the foregoing method for jointly positioning multiple satellites and specifically perform:

As will be appreciated by one skilled in the art, 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.) that include 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 flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams 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 a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

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

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 computer storage media 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 that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.

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 an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

As will be appreciated by one skilled in the art, 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.) characterized by computer-usable program code.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for jointly positioning a radiation source by multiple satellites, wherein the multiple satellites have overlapping operating frequency bands, the method comprising:

2. The method of claim 1, wherein obtaining the time reference errors and the frequency reference errors for the plurality of satellites comprises:

transmitting a calibration signal through a ground calibration station, and adjusting receiver frequency setting parameters of each satellite so as to enable the frequency of the calibration signal to be within a second receiver instantaneous working frequency band, wherein the second receiver instantaneous working frequency band is located within the overlapped working frequency band;

receiving the calibration signals through a plurality of satellites and carrying out digital sampling on the calibration signals to obtain sampled calibration signals and downloading the sampled calibration signals to a ground data processing system;

extracting the measurement time difference and the measurement 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;

according to the measurement time difference of the sampled calibration signals and the real time difference that the sampled calibration signals reach the satellites, the time reference errors of the satellites are determined, and according to the measurement frequency difference of the sampled calibration signals, the real frequency difference that the sampled calibration signals reach the satellites and the frequency of the sampled calibration signals, the frequency reference errors of the satellites are determined.

3. The method of claim 2, wherein the extracting the real time difference and the real frequency difference of the sampled calibration signals arriving at the plurality of satellites comprises:

determining the position vector and the relative velocity vector of each satellite in the geocentric fixed connection system and the frequency of the calibration signal of the ground calibration station;

extracting real time differences of the sampled calibration signals reaching the plurality of satellites according to the position vectors of the ground calibration station and each satellite in the geocentric fixed connection;

and extracting the real frequency difference of the sampled calibration signals reaching the plurality of satellites according to the ground calibration station, the position vector and the relative velocity vector of each satellite in the geocentric fixed connection system and the frequency of the calibration signals.

4. The method of claim 1, wherein 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 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 radiation source, a position vector and a relative velocity vector of each satellite in the earth-centered solid system, and the frequency of a radiation source signal;

correcting the time reference errors of the plurality of satellites according to the frequency reference errors and the time difference of the emission of 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 measurement time difference of the sampled radiation source signals and the position vectors of the radiation source and each satellite in the earth-centered fixed connection;

and 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 radiation source, the position vector and the relative velocity vector of each satellite in the earth-centered solid system, and the frequency of the radiation source signal.

5. The method of claim 1, wherein said performing the localization of the radiation source via the time difference equation and the frequency difference equation comprises:

determining a type of the radiation source;

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

and 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.

6. The method of claim 2, wherein said receiving radiation source signals emitted by radiation sources via said plurality of satellites comprises:

setting the receiver channelized sampling parameters on a plurality of satellites to be the same as the receiver channelized sampling parameters in calibration.

7. The method of claim 1, further comprising:

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

calculating a time difference measurement total error according to the precision analysis result of the time reference error, and calculating a frequency difference measurement total error according to the precision 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 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 accumulated time during positioning and a frequency difference estimation error of a radiation source signal;

and 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.

8. An apparatus for jointly positioning a plurality of satellites with overlapping operating frequency bands, comprising:

the radiation source signal receiving unit is used for receiving radiation source signals emitted by the radiation sources through the satellites and adjusting receiver set frequency parameters of the satellites so that the frequency of the radiation source signals is within a first receiver instantaneous working frequency band, wherein the first receiver instantaneous working frequency band is located in a working frequency band overlapped by the satellites;

9. The apparatus according to claim 8, wherein the reference error obtaining unit is specifically configured to:

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

the executable instructions, when executed by the processor, implement a method of jointly positioning a radiation source with multiple satellites as claimed in any one of claims 1 to 7.