Spacecraft relative position measurement method and device based on GNSS difference

Abstract

The present application provides a method and device for measuring the relative position of a spacecraft based on GNSS differential. The method includes obtaining a first long-wave observation combination and a second long-wave observation combination; performing a double-difference integer ambiguity search according to a pseudo-range double-difference linear equation and a carrier double-difference equation to determine N first integer ambiguities to be tested of the first long-wave observation combination and M second integer ambiguities to be tested of the second long-wave observation combination; determining the first integer ambiguity and the second integer ambiguity that meet the preset integer ambiguity conditions; and then determining the short-wave double-difference integer ambiguity to measure the relative position of the spacecraft. In this way, the multiple frequency observations provided by GNSS can be used to expand the carrier wavelength by linear combination, the search space of the integer ambiguity can be sparse, the search workload can be reduced, the solution time can be compressed, and the relative position of the spacecraft can be accurately measured, so that the real-time and high-precision requirements of the relative position measurement of the spacecraft can be met at the same time.

Description

Technical Field

[0001] The present application belongs to the field of aviation technology, and in particular relates to a method and device for measuring the relative position of a spacecraft based on GNSS differential. Background Art

[0002] With the continuous development of aerospace technology, the types of space missions have become more diverse and complex, and distributed space systems (DSS) have emerged. Satellite formation flight is a typical working mode of distributed aerospace systems, in which real-time and accurate relative position measurement is the input condition for formation control and the basic premise for maintaining and reconstructing formation configuration, avoiding collisions and ensuring safety. At present, the relative position measurement of the Global Navigation Satellite System (GNSS) often has difficulty in meeting the real-time and high-precision requirements of spacecraft relative position measurement at the same time. Summary of the invention

[0003] The embodiment of the present application provides a spacecraft relative position measurement method and device based on GNSS differential to solve the technical problem that the existing relative position measurement method is difficult to simultaneously meet the real-time and high-precision requirements of spacecraft relative position measurement.

[0004] In a first aspect, an embodiment of the present application provides a method for measuring a relative position of a spacecraft based on GNSS differential, the method comprising:

[0005] Obtain a first long-wave observation combination and a second long-wave observation combination;

[0006] Performing a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation to determine N first integer ambiguities to be checked of the first long-wave observation combination and M second integer ambiguities to be checked of the second long-wave observation combination, where N and M are integers greater than 1;

[0007] Determining a first integer ambiguity from the N first integer ambiguities to be checked, and determining a second integer ambiguity from the M second integer ambiguities to be checked, wherein both the first integer ambiguity and the second integer ambiguity satisfy a preset integer ambiguity condition;

[0008] A shortwave double-difference integer ambiguity is determined according to the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft.

[0009] In a second aspect, an embodiment of the present application provides a spacecraft relative position measurement device based on GNSS differential, the device comprising:

[0010] An acquisition module, used for acquiring a first long-wave observation combination and a second long-wave observation combination;

[0011] A first determination module, configured to perform a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation, to determine N first integer ambiguities to be checked of the first long-wave observation combination and M second integer ambiguities to be checked of the second long-wave observation combination, where N and M are integers greater than 1;

[0012] a second determining module, configured to determine a first integer ambiguity from the N first integer ambiguities to be checked, and to determine a second integer ambiguity from the M second integer ambiguities to be checked, wherein both the first integer ambiguity and the second integer ambiguity satisfy a preset integer ambiguity condition;

[0013] The measurement module is used to determine the shortwave double-difference integer ambiguity according to the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft.

[0014] In a third aspect, an embodiment of the present application provides an electronic device, the device comprising:

[0015] A processor and a memory storing programs or instructions;

[0016] The above method is implemented when the processor executes the program or instruction.

[0017] In a fourth aspect, an embodiment of the present application provides a readable storage medium, on which a program or instruction is stored, and the program or instruction implements the above method when executed by a processor.

[0018] In a fifth aspect, an embodiment of the present application provides a computer program product. When instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the above method.

[0019] The spacecraft relative position measurement method and device based on GNSS differential in the embodiment of the present application can obtain a first long-wave observation combination and a second long-wave observation combination; perform a double-difference integer ambiguity search according to a preset pseudo-range double-difference linear equation and a preset carrier double-difference equation to determine N first integer ambiguities to be tested of the first long-wave observation combination and M second integer ambiguities to be tested of the second long-wave observation combination; respectively determine the first integer ambiguity and the second integer ambiguity that meet the preset integer ambiguity conditions from the N first integer ambiguities to be tested and the M second integer ambiguities to be tested; and determine the short-wave double-difference integer ambiguity based on the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft. In this way, the multiple frequency observations provided by GNSS can be used to expand the carrier wavelength through linear combination, and the integer ambiguity of the first long-wave observation combination and the second long-wave observation combination after the expanded carrier wavelength can be searched, so as to sparse the search space of the integer ambiguity, reduce the search workload, compress the solution time, and obtain the short-wave double-difference integer ambiguity to accurately measure the relative position of the spacecraft. Therefore, it can simultaneously meet the real-time and high-precision requirements of the spacecraft relative position measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 It is a flowchart of a method for measuring relative position of a spacecraft based on GNSS differential provided by an embodiment of the present application;

[0022] Figure 2 This is a flow chart of a scenario implementation of a method for measuring relative position of a spacecraft based on GNSS differential provided in an embodiment of the present application;

[0023] Figure 3 It is the baseline length accuracy based on the long-wave double-difference integer ambiguity fixation;

[0024] Figure 4 It is the accuracy of the baseline component based on the long-wave double-difference integer ambiguity fixation;

[0025] Figure 5 is a schematic structural diagram of a spacecraft relative position measurement device based on GNSS differential provided in another embodiment of the present application;

[0026] Figure 6 It is a structural schematic diagram of an electronic device provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0027] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0029] In order to solve the problems of the prior art, the embodiment of the present application provides a method and device for measuring the relative position of a spacecraft based on the Global Navigation Satellite System (GNSS) differential. The following first introduces the method for measuring the relative position of a spacecraft based on the GNSS differential provided in the embodiment of the present application.

[0030] Figure 1 FIG. 1 is a flow chart of a method for measuring the relative position of a spacecraft based on GNSS differential according to an embodiment of the present application. Figure 1 As shown, the spacecraft relative position measurement method based on GNSS difference may include the following steps:

[0031] Step 101, obtaining a first long-wave observation combination and a second long-wave observation combination;

[0032] Step 102, performing a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation, and determining N first integer ambiguities to be checked for the first long-wave observation combination and M second integer ambiguities to be checked for the second long-wave observation combination, where N and M are integers greater than 1;

[0033] Step 103, determining a first integer ambiguity from the N first integer ambiguities to be checked, and determining a second integer ambiguity from the M second integer ambiguities to be checked, wherein both the first integer ambiguity and the second integer ambiguity satisfy a preset integer ambiguity condition;

[0034] Step 104, determining the shortwave double difference integer ambiguity according to the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft.

[0035] The specific implementation of each of the above steps will be described in detail below.

[0036] In an embodiment of the present application, a spacecraft relative position measurement method based on GNSS differential can obtain a first long-wave observation combination and a second long-wave observation combination; perform a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation to determine N first integer ambiguities to be tested of the first long-wave observation combination and M second integer ambiguities to be tested of the second long-wave observation combination; respectively determine the first integer ambiguity and the second integer ambiguity that meet the preset integer ambiguity conditions from the N first integer ambiguities to be tested and the M second integer ambiguities to be tested; and determine the shortwave double-difference integer ambiguity based on the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft. In this way, the multiple frequency observations provided by GNSS can be used to expand the carrier wavelength through linear combination, and the integer ambiguity of the first long-wave observation combination and the second long-wave observation combination after the expanded carrier wavelength can be searched, so as to sparse the search space of the integer ambiguity, reduce the search workload, compress the solution time, and obtain the short-wave double-difference integer ambiguity to accurately measure the relative position of the spacecraft. Therefore, it can simultaneously meet the real-time and high-precision requirements of the spacecraft relative position measurement.

[0037] The specific implementation methods of the above steps are introduced below.

[0038] In the embodiment of the present application, the pseudo-range double difference linear equation and the carrier double difference equation can be pre-established. For example, based on the GNSS pseudo-range observation equation, the L1 frequency point C / A code pseudo-range observation value C A i For example, the pseudorange observation equation expression can be shown as formula (1):

[0039]

[0040] in, It can represent the distance between receiver A and navigation satellite i; is the deviation of the receiver A clock relative to the GPS standard time, c is the speed of light in vacuum; δp i is the ephemeris error of navigation satellite i; It is the measurement deviation caused by the ionosphere on the signal propagation path; is the measurement deviation caused by the troposphere on the signal propagation path; It is the measurement deviation caused by the multipath effect on the signal propagation path; is the deviation caused by the earth's rotation effect; ε A The noise is measured locally at receiver A. The distance between receiver A and navigation satellite i is The expression of can be shown as formula (2):

[0041]

[0042] Among them, (x s i y s i z s i ) T is the exact coordinate of navigation satellite i in the earth fixed system at the time of signal transmission; (x A y A z A ) T is the exact coordinate of receiver A in the ground fixed system at the time of signal arrival.

[0043] Based on the carrier phase observation equation, The carrier phase measurement value of navigation satellite i can be observed at the L1 and L2 frequency points received by receiver A respectively. The carrier phase observation equation expression can be shown as formula (3):

[0044]

[0045] in, are the integer ambiguities of L1 and L2 frequency points respectively; λ1 and λ2 are the carrier wavelengths; It can represent the distance between receiver A and navigation satellite i; is the deviation of the receiver A clock relative to the GPS standard time, c is the speed of light in vacuum; δp i is the ephemeris error of navigation satellite i; It is the measurement deviation caused by the ionosphere on the signal propagation path; is the measurement deviation caused by the troposphere on the signal propagation path; It is the measurement deviation caused by the multipath effect on the signal propagation path; is the deviation caused by the earth's rotation effect; ε A The noise is measured locally for receiver A.

[0046] It is understandable that when the baseline formed by the two receivers (i.e., observation points) is short, the influence of atmospheric error sources has a strong correlation. The influence of error sources can be greatly reduced by difference between observation stations. The single difference between observation stations can eliminate satellite clock error and satellite ephemeris error. Receiver A and receiver B synchronously observe navigation satellite S i The pseudorange single difference equation expression can be shown as formula (4):

[0047]

[0048] Receiver A and receiver B synchronously observe navigation satellite S i The carrier phase single difference equation expression can be shown as formula (5):

[0049]

[0050] Among them, the approximate solution point It can be obtained through the single-point positioning method. It is understandable that the three-axis error of the current GPS single-point positioning algorithm can be controlled within 10m. In order to reduce the amount of calculation and save computing power, high-order terms can be ignored and only constant terms and first-order terms are considered. It is also understandable that for a baseline within 10km, the direction cosine deviation of the two end points of the baseline observing the same navigation star is within 5e -4 The influence on the baseline correction is no more than 5 mm. Here, the direction cosines of different endpoints can be approximated to obtain formula (6):

[0051]

[0052] Among them, (Δx AB Δy AB Δz AB ) T Initial baseline The correction value, the pseudorange equation can be expressed as formula (7):

[0053]

[0054] in, is the pseudorange constant term, e i is the direction cosine. When n satellites are observed synchronously, the pseudo-range single difference equation can be expressed as formula (8):

[0055]

[0056] The carrier phase single difference equation can be expressed as formula (9):

[0057]

[0058] Based on the pseudorange single difference equation and the carrier phase single difference equation, the same reference satellite S j By performing inter-satellite differential, we can obtain the pseudo-range double-difference linear equation and the carrier double-difference equation, which can further eliminate the receiver clock error.

[0059] The expression of the pseudorange double difference linear equation can be shown as formula (10):

[0060]

[0061] The expression of the carrier double difference equation can be shown as formula (11):

[0062]

[0063] Therefore, the pseudorange double difference linear equation can be expressed as formula (12):

[0064] y ρ =EΔb+ε ρ (12)

[0065] Among them, y ρ is the pseudorange constant term; E is the direction cosine matrix; Δb is the baseline length; ε ρ is the pseudorange error term.

[0066] The carrier double difference equation can be expressed as formula (13):

[0067]

[0068] in, is the carrier constant term; λ is the carrier wavelength; E is the direction cosine matrix; Δb is the baseline length; is the integer ambiguity of the L1 frequency point; ε ρ is the carrier error term.

[0069] In the embodiment of the present application, the first long wave observation combination and the second long wave observation combination can be obtained. It can be understood that in the high-precision baseline measurement, accurate integer ambiguity can be obtained by Measurements are performed. Using the multiple frequency observations provided by GNSS, the carrier wavelength can be expanded through linear combination, thereby sparsely searching the integer ambiguity, which can reduce the search workload and compress the solution time. Therefore, the first long-wave observation combination and the second long-wave observation combination after linear combination can be obtained. It can be understood that in order to solve the subsequent short-wave double-difference integer ambiguity, the first long-wave observation combination and the second long-wave observation combination need to satisfy a nonlinear relationship.

[0070] In order to ensure the integer characteristics of the integer ambiguity, the combination coefficients α and β of the first long-wave observation combination and the second long-wave observation combination must be integers, where the wavelength of the combination equation can be expressed as formula (14):

[0071]

[0072] The possible combinations are listed below:

[0073]

[0074] The relative noise can be expressed as formula (15):

[0075]

[0076] The relative ionospheric error can be expressed as formula (16):

[0077]

[0078] It can be seen that the noise of a single observation equation is amplified after the linear combination. Therefore, the first long-wave observation combination and the second long-wave observation combination can be used only for the search and determination of integer ambiguities. When the final baseline is solved, a more accurate baseline solution can be performed based on the short-wave double-difference integer ambiguity determined by the first integer ambiguity of the first long-wave observation combination and the second integer ambiguity of the second long-wave observation combination, thereby more accurately measuring the relative position of the spacecraft.

[0079] In some embodiments, the first long wave observation combination may be The second long wave observation combination can be Based on formula (13) and formula (14), we know that The corresponding long-wave measurement equation can be expressed as formula (17):

[0080]

[0081] The corresponding long-wave measurement equation can be expressed as formula (18):

[0082]

[0083] The combined integer ambiguity to be detected can be expressed as formula (19):

[0084]

[0085] The double-difference integer ambiguity search can be performed based on the pseudo-range double-difference linear equation and the carrier double-difference equation established in advance to determine the first long-wave observation combination (such as ) of the first integer ambiguities to be checked, and the second long-wave observation combination (such as ) of multiple second integer ambiguities to be checked.

[0086] It is understandable that each long-wave observation combination can search for multiple integer ambiguities to be checked, and the only correct integer ambiguity that meets the preset integer ambiguity condition can be determined from the multiple integer ambiguities to be checked to ensure the accuracy of the integer ambiguity search. The preset integer ambiguity condition can be that the channel residual corresponding to the integer ambiguity is within a preset residual interval, or that the residual square sum corresponding to the integer ambiguity satisfies a preset relationship, etc., which is not specifically limited here and can be set according to actual conditions.

[0087] Determine the correct first integer ambiguity (such as N L(1,-1)r ) and the second integer ambiguity (such as N L(-3,4)r ) can be obtained by the shortwave double difference integer ambiguity of the L1 frequency point Its expression can be shown as formula (20):

[0088]

[0089] The relative position of the spacecraft can be measured based on the shortwave double-difference integer ambiguity. For example, the distance between receiver A and the navigation satellite can be determined based on the shortwave double-difference integer ambiguity between the receiver A and the navigation satellite, and then the position of receiver A can be determined based on the distances between receiver A and multiple navigation satellites. Similarly, the position of receiver B can be determined, and then the relative position of receiver A and receiver B can be measured based on the position of receiver A and the position of receiver B.

[0090] Optionally, in some embodiments, the above step 102 may include the following steps:

[0091] When the original observation data is received, the initial solution point and ephemeris solution are obtained based on the pseudo-range single-point positioning to obtain the position coordinates between each navigation satellite among P navigation satellites and the receiver, where P is an integer greater than 1;

[0092] Determine the altitude angle of each navigation satellite based on the position coordinates between each navigation satellite and the receiver;

[0093] Determine the prior variance of the observation value according to the altitude angle of each navigation satellite, and the reference navigation satellite;

[0094] According to the prior variance and the reference navigation satellite, a covariance matrix of the prior variance is obtained;

[0095] Based on the covariance matrix, the observation weight matrix is ​​obtained;

[0096] Based on the observation weight matrix and the pseudorange double difference linear equation, the first baseline vector, the first channel residual and the weighted variance are obtained by solving to determine the first search interval;

[0097] According to the carrier double-difference equation, a double-difference integer ambiguity search is performed in the first search interval to determine N first integer ambiguities to be checked for the first long-wave observation combination and M second integer ambiguities to be checked for the second long-wave observation combination.

[0098] In this embodiment, after receiving the original observation data, the GNSS can obtain the initial solution point and ephemeris solution based on the pseudo-range single-point positioning, obtain the position coordinates between different navigation satellites and the receiver, and then calculate the altitude angle of each navigation satellite. It can be understood that the smaller the altitude angle, the worse the quality of the observation data. By weighting the data, the observation data of the navigation satellite with a large altitude angle can be given a higher weight. In this way, the influence of low-precision observations on relative position measurement can be reduced by weighting the observation values. The improved sine function model based on the altitude angle is used to describe the influence of the altitude angle on the carrier observation quality, and the prior variance of the observation value is calculated. The prior variance of the observation value can be shown as formula (21):

[0099]

[0100] Among them, taking the empirical value, we can get a = 4mm, b = 3mm. We can set the navigation satellite with the highest elevation angle as the reference star. If the reference star of the prior variance equation is S r , S 1,2,..k For a non-reference star, the covariance matrix of the prior variance equation can be shown as formula (22):

[0101]

[0102] Based on the covariance matrix, the observation weight matrix can be obtained, which can be shown as formula (23):

[0103] W=Z -1 (twenty three)

[0104] The low-precision first baseline vector can be solved by the least squares method based on the observation weight matrix and the pseudo-range double difference linear equation First channel residual and weighted variance

[0105]

[0106] Then the covariance matrix of the baseline vector can be:

[0107]

[0108] Based on this, the first search space of integer ambiguity can be Construct a cuboid as the center, where the intervals of each side of the cuboid can be:

[0109] Σ=Π([-TσΔx Tσ Δx ],[-Tσ Δy Tσ Δy ],[-Tσ Δz Tσ Δz ]) (26)

[0110] In the actual processing, T=2.4 can be taken, at which time the correct integer ambiguity can be covered with a probability of 95.2%.

[0111] According to the carrier double-difference equation, a double-difference integer ambiguity search can be performed in the first search interval to determine N first integer ambiguities to be checked for the first long-wave observation combination and M second integer ambiguities to be checked for the second long-wave observation combination.

[0112] In this embodiment, the first search interval can be determined by solving the first baseline vector, the first channel residual and the weighted variance, and the search range of the integer ambiguity can be limited in advance to a relatively small range, thereby further reducing the search workload, compressing the solution time and improving real-time performance.

[0113] It can be understood that if the correct integer ambiguity is not found in the first search interval, the search interval can be expanded based on the first search interval to obtain a second search interval, and a double difference integer ambiguity search can be performed in the second search interval according to the carrier double difference equation.

[0114] Optionally, in some embodiments, the N second channel residuals corresponding to the N first integer ambiguities to be checked are all located in a preset residual screening interval.

[0115] In this embodiment, the first long wave observation combination can be The second long wave observation combination can be For example, the first long-wave observation combination Pre-set the residual screening interval, where the residual screening interval can be (-4σ, 4σ) to exclude the first long wave observation combination The second channel residual of the first to-be-detected integer ambiguity is outside ±4σ. In this way, the search space of integer ambiguities can be further narrowed.

[0116] It is understandable that due to the second long-wave observation combination The error magnification is high. When the pseudorange error is large, the preset screening may filter out the correct integer ambiguity. At the same time, the second long wave observation combination The wavelength can reach 1.68m, and its search space is relatively large compared to the first long-wave observation combination. is more sparse, so the second long-wave observation combination can be omitted The second integer ambiguity to be tested is screened.

[0117] Optionally, in some embodiments, the above step 103 may include the following steps:

[0118] Determine Q residual sums of squares corresponding to the integer ambiguities of Q targets to be detected, where Q is an integer greater than 1;

[0119] Determine the minimum residual sum of squares and the second minimum residual sum of squares among the Q residual sums of squares;

[0120] When the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is greater than a preset first test threshold, the target integer ambiguity to be tested corresponding to the minimum residual sum of squares is determined as the target integer ambiguity;

[0121] Among them, when the Q target integer ambiguities to be checked are N first integer ambiguities to be checked, the target integer ambiguity is the first integer ambiguity; when the Q target integer ambiguities to be checked are M second integer ambiguities to be checked, the target integer ambiguity is the second integer ambiguity.

[0122] It is understandable that the long-wave observation combination The residual expression of can be shown as formula (27):

[0123]

[0124] Therefore, the residual sum of squares corresponding to the integer ambiguity of the target to be detected can be:

[0125]

[0126] Multiple residual sums of squares can be sorted from small to large to determine the minimum residual sum of squares and the sub-minimum residual sum of squares Minimize the residual sum of squares and the sub-minimum residual sum of squares Perform the first ratio test:

[0127]

[0128] The preset first detection threshold value threshold can be set according to actual conditions, for example, the first detection threshold value threshold=3.

[0129] In the sub-minimum residual sum of squares Minimum residual sum of squares When the ratio of is greater than a preset first test threshold, the target integer ambiguity to be tested corresponding to the minimum residual square sum can be determined as the correct target integer ambiguity.

[0130] Optionally, in some embodiments, after determining the minimum residual sum of squares and the second minimum residual sum of squares among the Q residual sums of squares, the spacecraft relative position measurement method based on GNSS difference may further include the following steps:

[0131] When the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is less than or equal to the first test threshold, sort the Q residual sums of squares from small to large;

[0132] When the ratio of the kth residual sum of squares to the minimum residual sum of squares is greater than a preset second test threshold, the target integer ambiguity to be tested corresponding to the minimum residual sum of squares is determined as the target integer ambiguity, where k is an integer greater than 1 and k is less than or equal to Q.

[0133] In this embodiment, if the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is less than or equal to the first test threshold, that is, the minimum residual sum of squares and the sub-minimum residual sum of squares If the first ratio test fails, a second ratio test can be performed.

[0134] For example, the residual sums of squares can be sorted from small to large Take out the first k corresponding integer ambiguities N L(α,β)1→k ,satisfy:

[0135]

[0136] The preset second test threshold th_long can be set according to actual conditions, for example, the second test threshold th_long = 4. In addition, the k value can be set according to actual conditions, and is not specifically limited here.

[0137] When the ratio of the kth residual sum of squares to the minimum residual sum of squares is greater than a preset second test threshold, the target integer ambiguity to be tested corresponding to the minimum residual sum of squares can be determined as the correct target integer ambiguity.

[0138] In some examples, if the target integer ambiguity to be tested fails both ratio tests, it may mean that the target integer ambiguity to be tested does not contain the correct solution. At this time, the search interval can be expanded, the corresponding integer ambiguity to be tested can be re-determined, and the ratio test can be performed again until it passes.

[0139] Optionally, in some embodiments, the above step 104 may include the following steps:

[0140] Determine the shortwave double-difference integer ambiguity to be checked and the third channel residual corresponding to the shortwave double-difference integer ambiguity to be checked according to the first integer ambiguity and the second integer ambiguity;

[0141] When the third channel residual is located in the preset residual detection interval, determining the shortwave double difference integer ambiguity to be detected as the shortwave double difference integer ambiguity;

[0142] The relative position of the spacecraft is measured based on the shortwave double-difference integer ambiguity.

[0143] In order to further improve the accuracy of relative position measurement, after determining the correct first integer ambiguity and second integer ambiguity, the shortwave double difference integer ambiguity to be checked and the third channel residual corresponding to the shortwave double difference integer ambiguity to be checked can be determined according to the first integer ambiguity and the second integer ambiguity. At this time, the third channel residual needs to be subjected to a significance test for final confirmation. If it passes, the shortwave double difference integer ambiguity to be checked can be considered to be the correct shortwave double difference integer ambiguity.

[0144] For example, it can be determined whether the third channel residual is in a preset residual detection interval. If the third channel residual is in the preset residual detection interval, it can be determined that the shortwave double difference integer ambiguity to be detected is the shortwave double difference integer ambiguity. The preset residual detection interval can be set according to actual conditions. For example, the third channel residual can be There is no combined channel residual, and the preset residual detection interval can be (-3σ, 3σ).

[0145] In some examples, if the third channel residual is not within the preset residual detection interval, it may indicate that the shortwave double-difference integer ambiguity to be detected is not the correct solution. At this time, the search interval may be expanded and the integer ambiguity search may be performed again until the correct shortwave double-difference integer ambiguity is finally obtained to measure the relative position of the spacecraft.

[0146] In order to facilitate understanding of the spacecraft relative position measurement method based on GNSS differential provided in the above embodiment, the above spacecraft relative position measurement method based on GNSS differential is described below with a specific scenario embodiment. Figure 2 A flow chart of a scenario implementation of the above-mentioned method for measuring relative position of spacecraft based on GNSS difference is shown.

[0147] like Figure 2 As shown, in this scenario embodiment, the first long wave observation combination can be The second long wave observation combination can be For example.

[0148] After receiving the raw observation data, GNSS can obtain the initial solution point and ephemeris solution based on pseudorange single-point positioning, obtain the position coordinates between different navigation satellites and the receiver, and then calculate the altitude angle of each navigation satellite. The observation value is weighted according to the altitude angle to determine the prior variance of the observation value. Based on the prior variance and the reference navigation satellite with the largest altitude angle, the covariance matrix of the prior variance is obtained, and the observation weight matrix is ​​obtained based on the covariance matrix. Then, based on the observation weight matrix and the pseudorange double-difference linear equation, the first baseline vector, the first channel residual and the weighted variance can be solved to determine the first search interval, and according to the carrier double-difference equation, a double-difference integer ambiguity search can be performed in the first search interval to determine and The integer unknown test set (i.e., N first integer ambiguities to be tested and M second integer ambiguities to be tested).

[0149] right and The integer unknown test set is subjected to a ratio test. If it passes, the correct integer ambiguity of each of them can be determined. If it fails, a second ratio test is required. If the second ratio test passes, the correct integer ambiguity can be determined. If it still fails, the test threshold can be increased and the group to be tested can be expanded (that is, the search interval can be expanded on the basis of the first search interval to obtain a second search interval, and the double difference integer ambiguity search can be re-performed in the second search interval) until the correct integer ambiguity is determined. and The respective correct integer ambiguity.

[0150] Can be based on and The correct integer ambiguity of each is obtained to obtain the shortwave double difference integer ambiguity to be detected and its corresponding There is no combined channel residual (i.e., the third channel residual), if If the uncombined channel residual is located at (-3σ, 3σ) (i.e., the preset residual detection interval), the shortwave double-difference integer ambiguity to be detected can be determined to be the shortwave double-difference integer ambiguity, and the precise baseline can be determined at this time. If the residual of the uncombined channel is not located at (-3σ, 3σ), the test threshold can be increased and the group to be tested can be expanded (that is, the search interval can be expanded on the basis of the first search interval to obtain the second search interval, and the double difference integer ambiguity search can be performed again in the second search interval) until The residual of the uncombined channel is located at (-3σ, 3σ).

[0151] It is understandable that once a precise baseline is determined, The uncombined channel residual is updated to the first channel residual. When the relative position measurement is performed next time, the updated channel residual can be used as the basis of the search interval to further reduce the search workload and improve the real-time performance.

[0152] The spacecraft relative position measurement method based on GNSS differential in this scenario embodiment can be verified by relative position measurement test, and the real-time precise baseline and three-axis components such as Figure 3 and Figure 4 As shown, the visible baseline vector is stable at the centimeter level, which effectively meets the high-precision requirements for measuring the relative position of the spacecraft.

[0153] Based on the spacecraft relative position measurement method based on GNSS differential provided in the above-mentioned embodiment, the present application also provides an embodiment of a spacecraft relative position measurement device based on GNSS differential.

[0154] Figure 5 A schematic structural diagram of a spacecraft relative position measurement device based on GNSS differential provided in another embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0155] Reference Figure 5 The spacecraft relative position measurement device 500 based on GNSS differential may include:

[0156] An acquisition module 501 is used to acquire a first long-wave observation combination and a second long-wave observation combination;

[0157] A first determination module 502 is configured to perform a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation to determine N first integer ambiguities to be checked of the first long-wave observation combination and M second integer ambiguities to be checked of the second long-wave observation combination, where N and M are integers greater than 1;

[0158] A second determining module 503 is configured to determine a first integer ambiguity from the N first integer ambiguities to be checked, and to determine a second integer ambiguity from the M second integer ambiguities to be checked, wherein both the first integer ambiguity and the second integer ambiguity satisfy a preset integer ambiguity condition;

[0159] The measurement module 504 is configured to determine the shortwave double-difference integer ambiguity according to the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft.

[0160] Optionally, in some embodiments, the first determining module 502 may also be used to:

[0161] When the original observation data is received, the initial solution point and ephemeris solution are obtained based on the pseudo-range single-point positioning to obtain the position coordinates between each navigation satellite among P navigation satellites and the receiver, where P is an integer greater than 1;

[0162] Determine the altitude angle of each navigation satellite based on the position coordinates between each navigation satellite and the receiver;

[0163] Determine the prior variance of the observation value according to the altitude angle of each navigation satellite, and the reference navigation satellite;

[0164] According to the prior variance and the reference navigation satellite, a covariance matrix of the prior variance is obtained;

[0165] Based on the covariance matrix, the observation weight matrix is ​​obtained;

[0166] Based on the observation weight matrix and the pseudorange double difference linear equation, the first baseline vector, the first channel residual and the weighted variance are obtained by solving to determine the first search interval;

[0167] According to the carrier double-difference equation, a double-difference integer ambiguity search is performed in the first search interval to determine N first integer ambiguities to be checked for the first long-wave observation combination and M second integer ambiguities to be checked for the second long-wave observation combination.

[0168] Optionally, in some embodiments, the first long wave observation combination is The second long wave observation combination is

[0169] Optionally, in some embodiments, the N second channel residuals corresponding to the N first integer ambiguities to be checked are all located in a preset residual screening interval.

[0170] Optionally, in some embodiments, the second determining module 503 may also be used to:

[0171] Determine Q residual sums of squares corresponding to the integer ambiguities of Q targets to be detected, where Q is an integer greater than 1;

[0172] Determine the minimum residual sum of squares and the second minimum residual sum of squares among the Q residual sums of squares;

[0173] When the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is greater than a preset first test threshold, the target integer ambiguity to be tested corresponding to the minimum residual sum of squares is determined as the target integer ambiguity;

[0174] Among them, when the Q target integer ambiguities to be checked are N first integer ambiguities to be checked, the target integer ambiguity is the first integer ambiguity; when the Q target integer ambiguities to be checked are M second integer ambiguities to be checked, the target integer ambiguity is the second integer ambiguity.

[0175] Optionally, in some embodiments, the spacecraft relative position measurement device 500 based on GNSS differential may further include a verification module, which may be used to:

[0176] When the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is less than or equal to the first test threshold, sort the Q residual sums of squares from small to large;

[0177] When the ratio of the kth residual sum of squares to the minimum residual sum of squares is greater than a preset second test threshold, the target integer ambiguity to be tested corresponding to the minimum residual sum of squares is determined as the target integer ambiguity, where k is an integer greater than 1 and k is less than or equal to Q.

[0178] Optionally, in some embodiments, the measurement module 504 may also be used to:

[0179] Determine the shortwave double-difference integer ambiguity to be checked and the third channel residual corresponding to the shortwave double-difference integer ambiguity to be checked according to the first integer ambiguity and the second integer ambiguity;

[0180] When the third channel residual is located in the preset residual detection interval, determining the shortwave double difference integer ambiguity to be detected as the shortwave double difference integer ambiguity;

[0181] The relative position of the spacecraft is measured based on the shortwave double-difference integer ambiguity.

[0182] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application, and are devices corresponding to the above-mentioned spacecraft relative position measurement method based on GNSS differential. All implementation methods in the above-mentioned method embodiment are applicable to the embodiment of the device. Its specific functions and technical effects brought about can be found in the method embodiment part, which will not be repeated here.

[0183] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0184] Figure 6 A schematic diagram of the hardware structure of an electronic device provided in yet another embodiment of the present application is shown.

[0185] The device may include a processor 601 and a memory 602 storing programs or instructions.

[0186] When the processor 601 executes the program, the steps in any of the above method embodiments are implemented.

[0187] Exemplarily, the program may be divided into one or more modules / units, one or more modules / units are stored in the memory 602 and executed by the processor 601 to complete the present application. One or more modules / units may be a series of program instruction segments capable of completing a specific function, and the instruction segments are used to describe the execution process of the program in the device.

[0188] Specifically, the processor 601 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0189] The memory 602 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 602 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In appropriate cases, the memory 602 may include a removable or non-removable (or fixed) medium. In appropriate cases, the memory 602 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 602 is a non-volatile solid-state memory.

[0190] The memory may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical or other physical / tangible memory storage devices. Thus, typically, the memory includes one or more tangible (non-transitory) readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0191] The processor 601 implements any one of the methods in the above embodiments by reading and executing the program or instruction stored in the memory 602 .

[0192] In one example, the electronic device may further include a communication interface 603 and a bus 604. The processor 601, the memory 602, and the communication interface 603 are connected via the bus 604 and communicate with each other.

[0193] The communication interface 603 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0194] Bus 604 includes hardware, software or both, and the parts of online data flow billing equipment are coupled to each other. For example, but not limitation, bus may include accelerated graphics port (AGP) or other graphics bus, enhanced industrial standard architecture (EISA) bus, front side bus (FSB), hypertransport (HT) interconnection, industrial standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 404 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the application considers any suitable bus or interconnection.

[0195] In addition, in combination with the method in the above embodiment, the embodiment of the present application can provide a readable storage medium for implementation. The readable storage medium stores a program or instruction; when the program or instruction is executed by a processor, any one of the methods in the above embodiment is implemented. The readable storage medium can be read by a machine such as a computer.

[0196] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0197] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0198] An embodiment of the present application provides a computer program product, which is stored in a readable storage medium. The program product is executed by at least one processor to implement the various processes of the above-mentioned method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0199] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0200] The functional modules shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. Programs or code segments can be stored in machine-readable media, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable media" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. Code segments can be downloaded via computer grids such as the Internet, intranets, etc.

[0201] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0202] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device (system) and program product according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by a computer program or instruction. These programs or instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0203] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A method for measuring relative position of a spacecraft based on GNSS differential, characterized in that: include: Obtain a first long-wave observation combination and a second long-wave observation combination; Performing a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation to determine N first integer ambiguities to be checked of the first long-wave observation combination and M second integer ambiguities to be checked of the second long-wave observation combination, where N and M are integers greater than 1; Determining a first integer ambiguity from the N first integer ambiguities to be checked, and determining a second integer ambiguity from the M second integer ambiguities to be checked, wherein both the first integer ambiguity and the second integer ambiguity satisfy a preset integer ambiguity condition; Determining a shortwave double-difference integer ambiguity according to the first integer ambiguity and the second integer ambiguity to measure a relative position of the spacecraft; Among them, the first long-wave observation combination and the second long-wave observation combination satisfy a nonlinear relationship; the first integer ambiguity is the only correct integer ambiguity among the N first integer ambiguities to be checked that satisfies the preset integer ambiguity condition; the second integer ambiguity is the only correct integer ambiguity among the M second integer ambiguities to be checked that satisfies the preset integer ambiguity condition.

2. The method according to claim 1, characterized in that The performing double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation to determine N first integer ambiguities to be checked of the first long-wave observation combination and M second integer ambiguities to be checked of the second long-wave observation combination includes: When the original observation data is received, the initial solution point and ephemeris solution are obtained based on the pseudo-range single-point positioning to obtain the position coordinates between each navigation satellite among P navigation satellites and the receiver, where P is an integer greater than 1; Determining the altitude angle of each navigation satellite according to the position coordinates between each navigation satellite and the receiver; Determining a priori variance of the observation value and a reference navigation satellite according to the altitude angle of each navigation satellite; Obtaining a covariance matrix of the prior variance according to the prior variance and the reference navigation satellite; Based on the covariance matrix, obtaining an observation weight matrix; Based on the observation weight matrix and the pseudorange double difference linear equation, a first baseline vector, a first channel residual and a weighted variance are obtained by solving the equation to determine a first search interval; According to the carrier double-difference equation, a double-difference integer ambiguity search is performed in the first search interval to determine N first integer ambiguities to be checked for the first long-wave observation combination and M second integer ambiguities to be checked for the second long-wave observation combination.

3. The method according to claim 1, characterized in that The first long-wave observation combination is The second long-wave observation combination is in, The carrier phase measurement value of the L1 frequency point navigation satellite received by the receiver; It is the carrier phase measurement value of the L2 frequency point navigation satellite observed by the receiver.

4. The method according to claim 3, characterized in that The N second channel residuals corresponding to the N first integer ambiguities to be checked are all located in a preset residual screening interval.

5. The method according to claim 1, characterized in that The determining of the first integer ambiguity from the N first integer ambiguities to be checked, and the determining of the second integer ambiguity from the M second integer ambiguities to be checked, comprises: Determine Q residual sums of squares corresponding to the integer ambiguities of Q targets to be detected, where Q is an integer greater than 1; Determine the minimum residual sum of squares and the second minimum residual sum of squares among the Q residual sums of squares; When the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is greater than a preset first test threshold, determining the target integer ambiguity to be tested corresponding to the minimum residual sum of squares as the target integer ambiguity; Among them, when the Q target integer ambiguities to be checked are N first integer ambiguities to be checked, the target integer ambiguity is the first integer ambiguity; when the Q target integer ambiguities to be checked are M second integer ambiguities to be checked, the target integer ambiguity is the second integer ambiguity.

6. The method according to claim 5, characterized in that After determining the minimum residual sum of squares and the second minimum residual sum of squares among the Q residual sums of squares, the method further includes: When the ratio of the second minimum residual sum of squares to the minimum residual sum of squares is less than or equal to the first test threshold, sorting the Q residual sums of squares from small to large; When the ratio of the kth residual sum of squares to the minimum residual sum of squares is greater than a preset second test threshold, the target integer ambiguity to be tested corresponding to the minimum residual sum of squares is determined as the target integer ambiguity, where k is an integer greater than 1 and k is less than or equal to Q.

7. The method according to claim 1, characterized in that Determining the shortwave double-difference integer ambiguity according to the first integer ambiguity and the second integer ambiguity to measure the relative position of the spacecraft comprises: Determining a shortwave double-difference integer ambiguity to be detected and a third channel residual corresponding to the shortwave double-difference integer ambiguity to be detected according to the first integer ambiguity and the second integer ambiguity; In the case where the third channel residual is located in a preset residual detection interval, determining the shortwave double-difference integer ambiguity to be detected as a shortwave double-difference integer ambiguity; The relative position of the spacecraft is measured based on the shortwave double-difference integer ambiguity.

8. A spacecraft relative position measurement device based on GNSS differential, characterized in that: The device comprises: An acquisition module, used for acquiring a first long-wave observation combination and a second long-wave observation combination; A first determination module, configured to perform a double-difference integer ambiguity search according to a preset pseudorange double-difference linear equation and a preset carrier double-difference equation, to determine N first integer ambiguities to be checked of the first long-wave observation combination and M second integer ambiguities to be checked of the second long-wave observation combination, where N and M are integers greater than 1; a second determining module, configured to determine a first integer ambiguity from the N first integer ambiguities to be checked, and to determine a second integer ambiguity from the M second integer ambiguities to be checked, wherein both the first integer ambiguity and the second integer ambiguity satisfy a preset integer ambiguity condition; A measurement module, configured to determine a shortwave double-difference integer ambiguity according to the first integer ambiguity and the second integer ambiguity, so as to measure a relative position of a spacecraft; Among them, the first long-wave observation combination and the second long-wave observation combination satisfy a nonlinear relationship; the first integer ambiguity is the only correct integer ambiguity among the N first integer ambiguities to be checked that satisfies the preset integer ambiguity condition; the second integer ambiguity is the only correct integer ambiguity among the M second integer ambiguities to be checked that satisfies the preset integer ambiguity condition.

9. An electronic device, characterized in that: The device comprises: a processor and a memory storing programs or instructions; When the processor executes the program or instruction, the method according to any one of claims 1 to 7 is implemented.

10. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

Images