Inter-satellite laser interference ranging frequency deviation calibration method and device

Abstract

The invention belongs to the technical field of satellite precision measurement, and discloses an inter-satellite laser interference ranging frequency deviation calibration method and device, and the method comprises the steps: obtaining a double-satellite position vector, and carrying out the calculation to obtain an inter-satellite baseline vector; calculating according to the inter-satellite baseline vector to obtain an inter-satellite distance variation rate; obtaining an interference phase and an initial laser absolute frequency, and calculating to obtain an LRI instantaneous distance variation rate; according to the inter-satellite distance variability and the LRI instantaneous distance variability, calculating to obtain an LRI instantaneous variability scale factor; obtaining a daily scale factor value according to the LRI instantaneous variable rate scale factor; constructing a linear trend model according to the daily scale factor value and obtaining a scale factor observation value; iteratively calculating the scale factor observation value to obtain the iterated scale factor observation value; judging whether a convergence condition is met; and if yes, outputting the iterated scale factor observation value. The method can improve the calculation precision and efficiency of calculating the absolute frequency of the laser in the inter-satellite laser ranging by using the satellite orbit data.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of satellite precise measurement, and in particular to an intersatellite laser interferometric ranging frequency deviation calibration method and device. BACKGROUND

[0002] The LRI calculates the distance change through the interference phase, but the calculated in-orbit satellite v M There are significant deviations; the first is the initial frequency deviation in the ground calibration stage, and the second is that the optical cavity resonance frequency is affected by temperature changes and material aging, resulting in optical cavity resonance frequency deviation. The frequency deviation will introduce system errors to the intersatellite measurement distance, and further affect the subsequent gravity field inversion accuracy and scientific applications.

[0003] At present, the LRI frequency deviation calibration methods mainly include the following four types, all of which have significant limitations. The first is the cross-calibration method relying on the KBR system, which has the disadvantage of significant non-continuity. The next generation of tasks (such as TIANQIN-2 and GRACE-C) will cancel the KBR system, losing the calibration reference; the second is the iodine molecular spectrum method, which requires a complex system and needs to add new on-board hardware, greatly increasing the technical difficulty and power consumption; the third is the telemetry data modeling method, which has insufficient model accuracy, cannot meet the requirements of gravity field inversion, and has the risk of model failure caused by material aging; the fourth is to directly estimate using orbit data, which has a large precision error. SUMMARY

[0004] The application provides an intersatellite laser interferometric ranging frequency deviation calibration method and device, which can use the existing orbit data of the gravity satellite as a reference for calculation, replacing the traditional KBR cross-calibration algorithm, and through the iterative weight function adjustment strategy and the linear trend model, the orbit random error and gross error are suppressed, the scale factor observation value after multiple iterations is obtained, and the frequency deviation calibration without additional hardware is realized according to the scale factor observation value after multiple iterations, and the calculation accuracy and efficiency of the absolute frequency of laser in the intersatellite laser ranging calculation using satellite orbit data are improved.

[0005] In a first aspect, the embodiments of the application provide an intersatellite laser interferometric ranging frequency deviation calibration method, which comprises:

[0006] Obtaining the position vectors of the two satellites based on GNSS precise orbit determination, and calculating the intersatellite baseline vector;

[0007] Calculating the intersatellite distance rate from the intersatellite baseline vector;

[0008] Obtaining the interference phase and the initial absolute frequency of laser, and calculating the instantaneous distance rate of LRI;

[0009] The LRI instantaneous range rate scale factor is calculated according to the inter-satellite range rate and the LRI instantaneous range rate;

[0010] The daily scale factor value is obtained according to the LRI instantaneous range rate scale factor;

[0011] The linear trend model is constructed according to the daily scale factor value, and the scale factor observation value is obtained according to the linear trend model;

[0012] The iterative step is to iteratively calculate the scale factor observation value by using the least square method and the iterative weight function adjustment strategy, and to obtain the iterated scale factor observation value;

[0013] It is judged whether the iterated scale factor observation value meets the convergence condition; if yes, the iterated scale factor observation value is output; if no, the iterative step is returned.

[0014] Further, the double-satellite position vectors are obtained based on GNSS precise orbiting, and the inter-satellite baseline vector is calculated, including:

[0015] The double-satellite position vectors are obtained based on GNSS precise orbiting, and the inter-satellite baseline vector is calculated according to the inter-satellite baseline vector calculation formula; the double-satellite position vectors include the first satellite position and the second satellite position;

[0016] The inter-satellite baseline vector calculation formula is:

[0017] b=r M -r T ;

[0018] Wherein, b is the inter-satellite baseline vector, r M is the first satellite position; r T is the second satellite position.

[0019] Further, the inter-satellite range rate is calculated according to the inter-satellite baseline vector, including:

[0020] The inter-satellite range rate is calculated according to the inter-satellite baseline vector and the inter-satellite range rate calculation formula;

[0021] The inter-satellite range rate calculation formula is:

[0022]

[0023] Wherein, is the inter-satellite range rate, and b is the inter-satellite baseline vector.

[0024] Further, the interference phase and the initial laser absolute frequency are obtained, and the LRI instantaneous range rate is calculated, including:

[0025] The LRI instantaneous range rate is calculated according to an LRI instantaneous range rate calculation formula based on the obtained interference phase and initial laser absolute frequency.

[0026] The LRI instantaneous range rate calculation formula is:

[0027]

[0028] wherein, is the LRI instantaneous range rate, φ is the interference phase, c0 is the light speed in vacuum, v M is the initial laser absolute frequency of the first satellite.

[0029] Further, the LRI instantaneous range rate scale factor is calculated according to the inter-satellite range rate and the LRI instantaneous range rate, and the LRI instantaneous range rate scale factor comprises:

[0030] The LRI instantaneous range rate scale factor is calculated according to the inter-satellite range rate, the LRI instantaneous range rate and an LRI instantaneous calculation formula.

[0031] The LRI instantaneous calculation formula is:

[0032]

[0033] wherein, s is the LRI instantaneous range rate scale factor, is the LRI instantaneous range rate, is the inter-satellite range rate, Δt LRI-orb is the time offset between the LRI data and the GNSS data.

[0034] Further, the daily scale factor value is obtained according to the LRI instantaneous range rate scale factor, and the daily scale factor value comprises:

[0035] The standard deviation of the LRI instantaneous range rate scale factor is calculated according to the LRI instantaneous range rate scale factor.

[0036] The LRI instantaneous range rate scale factor is screened according to the outlier range formula and the standard deviation of the LRI instantaneous range rate scale factor, and the daily scale factor value is obtained.

[0037] Further, a linear trend model is constructed according to the daily scale factor value, and the scale factor observation value is obtained according to the linear trend model, and the linear trend model comprises:

[0038] The linear trend model is converted into a matrix form according to the daily scale factor value, the scale factor drift rate, the initial deviation and the residual error, and the scale factor observation value is obtained.

[0039] The linear trend model is:

[0040] s orb =a(k) • t + b (k) + v (k) ;

[0041] The linear trend model is expressed in matrix form as:

[0042] s orb = Bx (k) + v (k) ;

[0043] The scale factor observation is:

[0044] s est (k) = Bx (k) ;

[0045] wherein x (k) = [a (k) , b (k) ], a (k) is a scale factor drift rate, b (k) is an initial bias, s orb is a n*1 observation vector of daily scale factor values, n is the number of scale factor observations, v (k) is a residual of the scale factor observation, k is the number of iterations; B is an n*2 design matrix, wherein the first column is all events t and the second column is all events 1.

[0046] Further, the iteration step, the scale factor observation is iteratively calculated by using the least square method and an iteration weight function adjustment strategy, to obtain an iterated scale factor observation, including:

[0047] The scale factor observation output by the linear trend model is solved by using the least square method, to obtain a least square solution;

[0048] The residual in the least square solution is input into the iteration weight function adjustment strategy, to obtain an iteration weight matrix;

[0049] The iteration weight function adjustment strategy is:

[0050]

[0051] wherein, is a diagonal line element in the iteration weight matrix in the kth iteration, i is the ith scale factor observation, σ is a standard deviation of the daily scale factor value, ω is a small constant to prevent overflow of the denominator; is a residual of the ith scale factor observation in the k-1th iteration;

[0052] The least square solution is updated according to the iteration weight matrix, and the updated least square solution is substituted into the linear trend model, to obtain the iterated scale factor observation.

[0053] Further, the convergence condition comprises:

[0054]

[0055] wherein, is the scaled factor observation after iteration of the kth iteration, is the scaled factor observation after iteration of the k-1th iteration.

[0056] In a second aspect, the embodiments of the present application provide a device for calibrating frequency bias of inter-satellite laser interferometric ranging, which comprises:

[0057] a vector module, configured to acquire a double-satellite position vector based on GNSS precise orbiting, and calculate an inter-satellite baseline vector;

[0058] an inter-satellite variability module, configured to calculate an inter-satellite distance variability based on the inter-satellite baseline vector;

[0059] an instantaneous variability module, configured to acquire an interference phase and an initial laser absolute frequency, and calculate an LRI instantaneous distance variability;

[0060] a calculation module, configured to calculate an LRI instantaneous distance variability scale factor based on the inter-satellite distance variability and the LRI instantaneous distance variability;

[0061] a screening module, configured to acquire a daily scale factor value based on the LRI instantaneous distance variability scale factor;

[0062] a model construction module, configured to construct a linear trend model based on the daily scale factor value, and acquire a scale factor observation value based on the linear trend model;

[0063] an iteration module, configured to iteratively calculate the scale factor observation value by using a least square method and an iteration weight function adjustment strategy, and acquire a scale factor observation value after iteration;

[0064] a judgment module, configured to judge whether the scale factor observation value after iteration meets a convergence condition; if yes, output the scale factor observation value after iteration; if no, return to the iteration module.

[0065] Further, the vector module is further configured to acquire a double-satellite position vector based on GNSS precise orbiting, and calculate an inter-satellite baseline vector based on an inter-satellite baseline vector calculation formula; the double-satellite position vector comprises a first satellite position and a second satellite position;

[0066] the inter-satellite baseline vector calculation formula is:

[0067] b = r M -r T ;

[0068] wherein, b is the inter-satellite baseline vector, r Mis a first satellite position; r T is a second satellite position.

[0069] Further, the inter-satellite variability module is further configured to calculate the inter-satellite distance variability according to an inter-satellite distance variability calculation formula and the inter-satellite baseline vector;

[0070] The inter-satellite distance variability calculation formula is:

[0071]

[0072] wherein, is the inter-satellite distance variability, and b is the inter-satellite baseline vector.

[0073] Further, the instantaneous variability module is further configured to obtain the interference phase and the initial laser absolute frequency, and calculate the LRI instantaneous distance variability according to an LRI instantaneous distance variability calculation formula;

[0074] The LRI instantaneous distance variability calculation formula is:

[0075]

[0076] wherein, is the LRI instantaneous distance variability, φ is the interference phase, c0 is the speed of light in vacuum, and v M is the initial laser absolute frequency of the first satellite.

[0077] In a third aspect, an embodiment of the present application provides a computer device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to perform the steps of the inter-satellite laser interferometric ranging frequency deviation calibration method according to any one of the above embodiments.

[0078] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executable on a processor to implement the steps of the inter-satellite laser interferometric ranging frequency deviation calibration method according to any one of the above embodiments.

[0079] In summary, compared with the prior art, the technical scheme provided by the embodiments of the present application has at least the following beneficial effects:

[0080] This application provides a method for calibrating the frequency deviation in inter-satellite laser interferometric ranging. This method can use existing orbital data of gravity satellites as a reference for calculation, replacing the traditional KBR cross-calibration algorithm. Furthermore, it uses an iterative weight function adjustment strategy and a linear trend model to jointly suppress orbital random errors and gross errors, obtaining scale factor observations after multiple iterations. Based on the scale factor observations after multiple iterations, frequency deviation calibration without additional hardware is achieved, improving the accuracy and efficiency of calculating the absolute laser frequency in inter-satellite laser ranging using satellite orbital data. Attached Figure Description

[0081] Figure 1 This is a flowchart of a frequency deviation calibration method for inter-satellite laser interferometry provided as an exemplary embodiment of this application.

[0082] Figure 2 This is a structural diagram of an inter-satellite laser interferometry frequency deviation calibration device provided as an exemplary embodiment of this application. Detailed Implementation

[0083] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0084] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0085] Please see Figure 1 This application provides a method for calibrating the frequency deviation of inter-satellite laser interferometric ranging, which specifically includes the following steps:

[0086] Step S1: Obtain the position vectors of the two satellites based on GNSS precise orbit determination, and calculate the inter-satellite baseline vector.

[0087] Among them, the inter-satellite baseline vector is calculated based on the position vector of the two satellites obtained by precise GNSS orbit determination, including:

[0088] Obtain the position vectors of the two satellites, and calculate the inter-satellite baseline vector according to the formula for calculating the inter-satellite baseline vector; the position vectors of the two satellites include the positions of the first satellite and the second satellite.

[0089] The formula for calculating the inter-satellite baseline vector is:

[0090] b = r M -r T ;

[0091] Where b is the inter-satellite baseline vector, r M The first satellite position; rT is a second satellite position.

[0092] Specifically, the accurate position vectors of the two satellites (i.e., the first satellite position and the second satellite position) are obtained, and the inter-satellite baseline vector is calculated according to the accurate position vectors of the two satellites, so as to guarantee the accuracy of the satellite orbit data, and the vector calculation can further lay a solid data foundation for the accurate processing of the satellite orbit data.

[0093] In step S2, the inter-satellite distance rate of change is calculated according to the inter-satellite baseline vector.

[0094] The inter-satellite distance rate of change calculated according to the inter-satellite baseline vector includes:

[0095] The inter-satellite distance rate of change is calculated according to the inter-satellite baseline vector and the inter-satellite distance rate of change calculation formula.

[0096] The inter-satellite distance rate of change calculation formula is:

[0097]

[0098] wherein, is the inter-satellite distance rate of change, and b is the inter-satellite baseline vector.

[0099] Specifically, the inter-satellite baseline vector obtained in step S1 is calculated, the first-order derivative of the vector of the inter-satellite baseline vector is calculated, and the modulus value of the inter-satellite baseline vector is calculated, and then the above formula is substituted and calculated, so as to obtain the inter-satellite distance rate of change. The inter-satellite distance rate of change can avoid the system error when the ambiguity bias is estimated.

[0100] In some embodiments, the acceleration is obtained according to the acceleration calculation formula; and the acceleration calculation formula is:

[0101]

[0102] wherein, is the acceleration, and b is the inter-satellite baseline vector. Further calculation of the inter-satellite baseline vector can obtain the inter-satellite acceleration, which adds a data basis for subsequent possible data use.

[0103] In step S3, the interference phase and the initial laser absolute frequency are obtained, and the LRI instantaneous distance rate of change is calculated.

[0104] The interference phase and the initial laser absolute frequency are obtained, and the LRI instantaneous distance rate of change is calculated, including:

[0105] The interference phase and the initial laser absolute frequency are obtained, and the LRI instantaneous distance rate of change is calculated according to the LRI instantaneous distance rate of change calculation formula.

[0106] The LRI instantaneous range rate calculation formula is:

[0107]

[0108] wherein, is the LRI instantaneous range rate, φ is the interference phase, c0 is the light speed in vacuum, v M is the initial laser absolute frequency of the first satellite (i.e. the on-orbit nominal value).

[0109] Step S4, the LRI instantaneous range rate scale factor is calculated according to the inter-satellite range rate and the LRI instantaneous range rate.

[0110] wherein, the orbit LRI instantaneous range rate scale factor is calculated according to the inter-satellite range rate and the LRI instantaneous range rate, comprising:

[0111] The LRI instantaneous range rate scale factor is calculated according to the inter-satellite range rate, the LRI instantaneous range rate and the LRI instantaneous calculation formula;

[0112] The LRI instantaneous calculation formula is:

[0113]

[0114] wherein, s is the LRI instantaneous range rate scale factor, is the LRI instantaneous range rate, is the inter-satellite range rate, Δt LRI-orb is the time offset between the LRI data and the GNSS data.

[0115] Specifically, similar to the calculation method of the KBR system, the calculation method of the orbit scale factor is optimized. The satellite orbit data is used for further calculation in the application, instead of the calculation data of the KBR system in the traditional scheme, so that the data is more accurate and the calculation is faster in the frequency deviation calibration of the satellite data.

[0116] Specifically, the cross-calibration formula depending on the KBR system is as follows:

[0117]

[0118] wherein:

[0119]

[0120] wherein, is the LRI instantaneous range rate, is the KBR instantaneous range rate, is the LRI biased range rate, is the KBR biased range rate, is the LRI instantaneous range rate scale factor, is the KBR instantaneous range rate scale factor, is the KBR antenna phase center correction for range rate, s is the LRI instantaneous range rate scale factor, Δt LRI-KBR is the time bias between LRI and KBR ranging systems.

[0121] Step S5, obtaining a daily scale factor value according to the LRI instantaneous range rate scale factor.

[0122] wherein the daily scale factor value is obtained according to the LRI instantaneous range rate scale factor, and the obtaining comprises:

[0123] calculating a standard deviation of the LRI instantaneous range rate scale factor according to the LRI instantaneous range rate scale factor;

[0124] screening the LRI instantaneous range rate scale factor according to an outlier range formula and the standard deviation of the LRI instantaneous range rate scale factor to obtain the daily scale factor value.

[0125] Specifically, the outlier range formula is:

[0126] s orb < mean(s orb )-3std(s orb ), or s orb > mean(s orb )+3std(s orb );

[0127] wherein std(s orb ) is the standard deviation of the LRI instantaneous range rate scale factor, and s orb is the daily scale factor value.

[0128] In some embodiments, the scale factor calculated by orbit calculation is usually affected by large random errors and gross errors, and thus the application needs to remove outliers first. If the absolute value of the residual of the orbit data and the laser ranging data exceeds three times of the standard deviation, it is considered as a gross error. For example, the residual standard deviation of the range rate of the orbit data and the laser ranging range rate is usually 1x10 -5 m / s, and the data with the absolute value of the residual exceeding 3x10 -5 m / s is considered as a gross error.

[0129] Specifically, the range of the outlier is set to three times of the standard deviation of the daily scale factor value s orb . The removing step is: calculating the standard deviation (std(s orb )) of the scale factor estimate s orb ; if the s orb value is less than mean(sorb )-3std(s orb ) or greater than mean(s orb )+3std(s orb ) is considered as an outlier. The removal of outliers can make the remaining data more accurate, further improving the accuracy of laser interferometric distance measurement. Setting the range of outliers can prevent values within the range from being removed incorrectly, ensuring the integrity of the data; at the same time, it can remove the difference outside the range, ensuring the accuracy of the data.

[0130] Step S6, constructing a linear trend model according to the daily scale factor value, and obtaining a scale factor observation value according to the linear trend model.

[0131] Wherein, the linear trend model is constructed according to the daily scale factor value, and the scale factor observation value is obtained according to the linear trend model, comprising:

[0132] According to the daily scale factor value, the scale factor drift rate, the initial deviation and the residual, the linear trend model is constructed, the linear trend model is converted into a matrix form, and the scale factor observation value is obtained;

[0133] The linear trend model is:

[0134] s orb =a (k) ·t+b (k) +v (k) ;

[0135] The linear trend model is expressed in a matrix form as:

[0136] s orb =Bx (k) +v (k) ;

[0137] The scale factor observation value is:

[0138] s est (k) =Bx (k) ;

[0139] Wherein, x (k) =[a (k) ,b (k) ], a (k) is the scale factor drift rate, b (k) is the initial deviation, s orb is the daily scale factor value of the n*1 observation vector, n is the number of scale factor observation values, v (k) is the residual of the scale factor observation value, and k is the iteration number; B is an n*2 design matrix, wherein the first column is t and the second column is 1.

[0140] Step S7, iteration step, adopting least square method and iteration weight function adjustment strategy to iteratively calculate the scale factor observation value, to obtain the iterated scale factor observation value.

[0141] The least square method and the iteration weight function adjustment strategy are adopted to iteratively calculate the scale factor observation value, to obtain the iterated scale factor observation value, including:

[0142] The least square method is adopted to solve the scale factor observation value output by the linear trend model, to obtain the least square solution.

[0143] The residual in the least square solution is input into the iteration weight function adjustment strategy, to obtain the iteration weight matrix.

[0144] The iteration weight function adjustment strategy is:

[0145]

[0146] Wherein, is the diagonal element in the iteration weight matrix in the kth iteration, i is the ith scale factor observation value, σ is the standard deviation of the daily scale factor value, ω is a small constant to prevent overflow of the denominator; is the residual of the ith scale factor observation value in the k-1th iteration.

[0147] Preferably, ω can be set to 1×10 -10 .

[0148] The least square solution is updated according to the iteration weight matrix, and the updated least square solution is substituted into the linear trend model, to obtain the iterated scale factor observation value.

[0149] Wherein, the least square calculation process in the first iteration is:

[0150] x (1) =(B T P (1) B) -1 B T P (1) s orb ;

[0151] v (1) =s orb -Bx (1) ;

[0152]

[0153] Wherein, P (1) is the iteration weight matrix in the first iteration.

[0154] Step S8, judging whether the scale factor observation after iteration meets the convergence condition; if yes, outputting the scale factor observation after iteration; if no, returning to the iteration step.

[0155] The convergence condition includes:

[0156]

[0157] The convergence condition includes: is the scale factor observation after iteration of the kth iteration, is the scale factor observation after iteration of the k-1th iteration.

[0158] In some embodiments, the fitting accuracy is evaluated by the root mean square value (σ s ) of the residual of the KBR scale factor estimation (s kbr ), that is: σ s The smaller the value is, the higher the accuracy of the scale factor observation after iteration is. The iteration process is repeated until the scale factor observation after iteration converges, which can improve the accuracy of the scale factor observation after iteration through multiple calculations, and realize the frequency bias calibration without additional hardware.

[0159] The above-mentioned embodiment provides an inter-satellite laser interferometric ranging frequency bias calibration method. The method can use the existing orbit data of the gravity satellite as a reference for calculation, replacing the traditional KBR cross-calibration algorithm. The orbit random error and gross error are suppressed by the iteration weight function adjustment strategy and the linear trend model, and the scale factor observation after multiple iterations is obtained. The frequency bias calibration without additional hardware is realized according to the scale factor observation after multiple iterations, and the calculation accuracy and efficiency of the absolute frequency of laser in the inter-satellite laser ranging based on satellite orbit data are improved.

[0160] Referring to Figure 2 , another embodiment of the present application provides an inter-satellite laser interferometric ranging frequency bias calibration device, which comprises:

[0161] The vector module 101 is configured to obtain the double-satellite position vector based on the GNSS precise orbit, and calculate the inter-satellite baseline vector.

[0162] The inter-satellite variability module 102 is configured to calculate the inter-satellite distance variability based on the inter-satellite baseline vector.

[0163] The instantaneous variability module 103 is configured to obtain the interference phase and the initial absolute frequency of laser, and calculate the LRI instantaneous distance variability.

[0164] The calculation module 104 is configured to calculate the LRI instantaneous distance variability scale factor based on the inter-satellite distance variability and the LRI instantaneous distance variability.

[0165] The screening module 105 is configured to obtain a daily scale factor value according to the LRI instantaneous distance rate of change scale factor;

[0166] The model construction module 106 is configured to construct a linear trend model according to the daily scale factor value, and obtain a scale factor observation value according to the linear trend model;

[0167] The iteration module 107 is configured to iteratively calculate the scale factor observation value by using a least square method and an iterative weight function adjustment strategy, and obtain an iterated scale factor observation value;

[0168] The judgment module 108 is configured to judge whether the iterated scale factor observation value meets a convergence condition; if yes, the iterated scale factor observation value is output; if no, the iteration module 107 is returned.

[0169] In some embodiments, the vector module is further configured to obtain a double-satellite position vector based on GNSS precise orbiting, and calculate an inter-satellite baseline vector according to an inter-satellite baseline vector calculation formula; the double-satellite position vector includes a first satellite position and a second satellite position;

[0170] The inter-satellite baseline vector calculation formula is:

[0171] b = r M -r T ;

[0172] Wherein, b is the inter-satellite baseline vector, r M is the first satellite position; r T is the second satellite position.

[0173] In some embodiments, the inter-satellite rate of change module is further configured to calculate an inter-satellite distance rate of change according to the inter-satellite baseline vector and an inter-satellite distance rate of change calculation formula;

[0174] The inter-satellite distance rate of change calculation formula is:

[0175]

[0176] Wherein, is the inter-satellite distance rate of change, and b is the inter-satellite baseline vector.

[0177] In some embodiments, the instantaneous rate of change module is further configured to obtain an interference phase and an initial laser absolute frequency, and calculate an LRI instantaneous distance rate of change according to an LRI instantaneous distance rate of change calculation formula;

[0178] The LRI instantaneous distance rate of change calculation formula is:

[0179]

[0180] Wherein, is the LRI instantaneous range rate, φ is the interference phase, c0is the speed of light in vacuum, v M is the initial laser absolute frequency of the first satellite (i.e. the on-orbit nominal value).

[0181] The specific limitations of the inter-satellite laser interferometric distance measurement frequency deviation calibration device provided in the embodiments can be referred to the embodiments of the inter-satellite laser interferometric distance measurement frequency deviation calibration method, which will not be repeated here. Each module in the inter-satellite laser interferometric distance measurement frequency deviation calibration device can be realized by software, hardware and combinations thereof, in whole or in part. Each module can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to be called and executed by the processor to perform the operations corresponding to each module.

[0182] The computer device provided in the embodiments of the present application can include a processor, a memory, a network interface and a database connected by a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The network interface of the computer device is used to communicate with an external terminal through a network connection. The computer program is executed by the processor, so that the processor performs the steps of the inter-satellite laser interferometric distance measurement frequency deviation calibration method of any one of the above embodiments.

[0183] The working process, working details and technical effects of the computer device provided in the embodiments can be referred to the embodiments of the inter-satellite laser interferometric distance measurement frequency deviation calibration method, which will not be repeated here.

[0184] The computer readable storage medium provided in the embodiments of the present application has a computer program stored thereon, and the computer program is executed by the processor to implement the steps of the inter-satellite laser interferometric distance measurement frequency deviation calibration method of any one of the above embodiments. The computer readable storage medium refers to a carrier for storing data, which can include, but is not limited to, floppy disks, optical disks, hard disks, flash memories, USB flash disks and / or Memory Sticks, etc. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable devices.

[0185] The working process, working details and technical effects of the computer readable storage medium provided in the embodiments can be referred to the embodiments of the inter-satellite laser interferometric distance measurement frequency deviation calibration method, which will not be repeated here.

[0186] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, storage, databases, or other media in the embodiments provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0187] The technical features of the above embodiments can be combined in any way. In order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present application.

[0188] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, some modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for calibrating the frequency deviation of inter-satellite laser interferometric ranging, characterized in that, The method includes: Based on GNSS precise orbit determination, the position vectors of the two satellites are obtained, and the inter-satellite baseline vector is calculated. The inter-satellite distance variability is calculated based on the inter-satellite baseline vector. The interference phase and initial absolute laser frequency are obtained, and the instantaneous distance variation rate of LRI is calculated. The LRI instantaneous distance variation scale factor is calculated based on the inter-satellite distance variation and the LRI instantaneous distance variation. The day-scale factor value is obtained based on the LRI instantaneous distance variability scaling factor; A linear trend model is constructed based on the daily scale factor values, and the scale factor observation values ​​are obtained based on the linear trend model. The iterative step involves using the least squares method and an iterative weight function adjustment strategy to iteratively calculate the scale factor observations, thereby obtaining the iterative scale factor observations. Determine whether the scale factor observation value after the iteration satisfies the convergence condition; if yes, output the scale factor observation value after the iteration; if no, return to the iteration step.

2. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 1, characterized in that, The method of obtaining the position vectors of two satellites based on GNSS precise orbit determination and calculating the inter-satellite baseline vector includes: The position vectors of the two satellites are obtained based on precise orbit determination using GNSS, and the inter-satellite baseline vector is calculated according to the inter-satellite baseline vector calculation formula; the position vectors of the two satellites include the positions of the first satellite and the second satellite. The formula for calculating the inter-satellite baseline vector is: b＝r M -r T ； Where b is the inter-satellite baseline vector, r M The first satellite position; r T This is the location of the second satellite.

3. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 1, characterized in that, The calculation of inter-satellite distance variation based on the inter-satellite baseline vector includes: The inter-satellite distance variation is calculated based on the inter-satellite baseline vector and the inter-satellite distance variation calculation formula. The formula for calculating the inter-satellite distance variation is: in, denoted as , and b as the inter-satellite distance variation.

4. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 1, characterized in that, The process of acquiring the interference phase and the initial absolute laser frequency, and calculating the instantaneous distance variation rate of the LRI, includes: The interference phase and initial absolute laser frequency are obtained, and the instantaneous distance variation of LRI is calculated according to the formula for calculating the instantaneous distance variation of LRI. The formula for calculating the instantaneous distance variation rate of LRI is: in, Let φ be the instantaneous distance variation of the LRI, φ be the interference phase, c0 be the speed of light in vacuum, and v be the velocity of light. M The initial absolute frequency of the laser for the first satellite.

5. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 1, characterized in that, The calculation of the LRI instantaneous distance variation scale factor based on the inter-satellite distance variation and the LRI instantaneous distance variation includes: The LRI instantaneous distance variation scale factor is calculated based on the inter-satellite distance variation, the LRI instantaneous distance variation, and the LRI instantaneous calculation formula. The instantaneous calculation formula for LRI is as follows: Where s is the instantaneous distance variability scaling factor of LRI. For LRI instantaneous distance variability, For the interstellar distance variability, Δt LRI-orb This represents the time offset between LRI data and GNSS data.

6. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 1, characterized in that, The process of obtaining the day-scale factor value based on the LRI instantaneous distance variability scaling factor includes: Calculate the standard deviation of the LRI instantaneous distance variability scaling factor based on the LRI instantaneous distance variability scaling factor; The LRI instantaneous distance variability scale factor is selected based on the outlier range formula and the standard deviation of the LRI instantaneous distance variability scale factor to obtain the daily scale factor value.

7. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 1, characterized in that, The step of constructing a linear trend model based on the daily scale factor values ​​and obtaining the scale factor observations based on the linear trend model includes: A linear trend model is constructed based on the daily scale factor values, scale factor drift rate, initial bias and residual. The linear trend model is then converted into matrix form to obtain the scale factor observations. The linear trend model is as follows: s orb =a (k) ·t+b (k) +v (k) ; The linear trend model can be represented in matrix form as follows: s orb =Bx (k) +v (k) ; The observed values ​​for the scaling factor are: s est (k) =Bx (k) ; Where, x (k) =[a (k) ,b (k) ], a (k) b is the scale factor drift rate. (k) For the initial deviation, s orb v represents the diurnal scale factor value of an n*1 observation vector, where n is the number of scale factor observations. (k) denoted as the residual of the scale factor observations, k is the number of iterations; B is an n*2 design matrix, where the first column represents the average event t and the second column represents the average event 1.

8. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 7, characterized in that, The iterative step employs the least squares method and an iterative weight function adjustment strategy to iteratively calculate the scale factor observations, obtaining the iteratively calculated scale factor observations, including: The least squares method is used to solve for the scale factor observations output by the linear trend model to obtain the least squares solution; The residuals in the least squares solution are input into the iterative weight function to adjust the strategy, resulting in the iterative weight matrix; The iterative weight function adjustment strategy is as follows: in, Let be the diagonal element in the iteration weight matrix of the k-th iteration, i be the i-th scale factor observation, σ be the standard deviation of the daily scale factor value, and ω be a small constant to prevent denominator overflow. The residual of the observation value of the i-th scale factor at the (k-1)-th iteration; The least squares solution is updated based on the iterative weight matrix, and the updated least squares solution is substituted into the linear trend model to obtain the iterative scale factor observations.

9. The inter-satellite laser interferometric ranging frequency deviation calibration method according to claim 8, characterized in that, The convergence conditions include: in, The scale factor observation value after the k-th iteration. The scale factor observation value after the (k-1)th iteration.

10. A frequency deviation calibration device for inter-satellite laser interferometric ranging, characterized in that, The device includes: The vector module is used to obtain the position vectors of the two satellites based on GNSS precise orbit determination and to calculate the inter-satellite baseline vector. The inter-satellite rate module is used to calculate the inter-satellite distance rate based on the inter-satellite baseline vector. The instantaneous rate module is used to obtain the interference phase and the initial absolute laser frequency, and to calculate the instantaneous distance rate of the LRI. The calculation module is used to calculate the LRI instantaneous distance variation scale factor based on the inter-satellite distance variation and the LRI instantaneous distance variation. The filtering module is used to obtain the day-scale factor value based on the LRI instantaneous distance variability scale factor; The model building module is used to construct a linear trend model based on the daily scale factor values ​​and to obtain the scale factor observation values ​​based on the linear trend model. The iterative module is used to iteratively calculate the scale factor observations using the least squares method and an iterative weight function adjustment strategy to obtain the iterative scale factor observations. The judgment module is used to determine whether the scale factor observation value after iteration satisfies the convergence condition; if yes, the scale factor observation value after iteration is output; if no, the iteration module is returned.

11. The inter-satellite laser interferometric ranging frequency deviation calibration device according to claim 10, characterized in that, The vector module is also used to obtain the position vector of the two satellites based on GNSS precise orbit determination, and to calculate the inter-satellite baseline vector according to the inter-satellite baseline vector calculation formula; the position vector of the two satellites includes the position of the first satellite and the position of the second satellite. The formula for calculating the inter-satellite baseline vector is: b＝r M -r T ； Where b is the inter-satellite baseline vector, r M The first satellite position; r T This is the location of the second satellite.

12. The inter-satellite laser interferometric ranging frequency deviation calibration device according to claim 10, characterized in that, The inter-satellite variability module is also used to calculate the inter-satellite distance variability based on the inter-satellite baseline vector and the inter-satellite distance variability calculation formula. The formula for calculating the inter-satellite distance variation is: in, denoted as , and b as the inter-satellite distance variation.

13. The inter-satellite laser interferometric ranging frequency deviation calibration device according to claim 10, characterized in that, The instantaneous rate module is also used to obtain the interference phase and the initial absolute frequency of the laser, and to calculate the LRI instantaneous distance rate according to the LRI instantaneous distance rate calculation formula; The formula for calculating the instantaneous distance variation rate of LRI is: in, Let φ be the instantaneous distance variation of the LRI, φ be the interference phase, c0 be the speed of light in vacuum, and v be the velocity of light. M The initial absolute frequency of the laser for the first satellite.

14. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the inter-satellite laser interferometric ranging frequency deviation calibration method as described in any one of claims 1 to 9.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the inter-satellite laser interferometric ranging frequency deviation calibration method as described in any one of claims 1 to 9.

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