Optical satellite constellation comprehensive quality evaluation method

Abstract

The application relates to a kind of optical satellite constellation comprehensive quality evaluation methods;Satellite constellation can effectively improve the overall performance of satellite through multi-satellite networking, and the comprehensive quality evaluation of satellite constellation is an important factor in satellite efficiency analysis, while the multi-satellite comprehensive quality evaluation process is affected by the inconsistency of geometric radiation, the application proposes an optical satellite constellation comprehensive quality evaluation system based on load observation ability and orbit coverage ability analysis, and the comprehensive quality evaluation of satellite constellation is realized by using multi-satellite quality consistency processing method, and the satellite constellation comprehensive quality evaluation result obtained by the method is more comprehensive and reliable, which can provide technical basis for subsequent domestic optical satellite constellation comprehensive quality evaluation.

Description

Technical Field

[0001] This invention relates to a method for comprehensive quality assessment of optical satellite constellations. Background Technology

[0002] Currently, there are many comprehensive quality assessment methods and applications for satellites and satellite systems. These are mainly based on the characteristics of satellites and different mission requirements. Different types of satellites have different satellite performance assessment index systems proposed in different application scenarios or mission directions.

[0003] However, for the emerging satellite constellation technology, traditional satellite comprehensive performance evaluation simply calculates the comprehensive performance of each individual satellite in the constellation and uses the performance of the best individual satellite in the constellation to represent the performance of the entire constellation. It does not process or correct the overall comprehensive performance of the satellite constellation. The comprehensive performance of the satellite constellation calculated in this way cannot reflect the overall situation of the constellation well. At the same time, there is an urgent need to supplement some evaluation indicators that reflect the relationship between multiple satellites in the constellation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a comprehensive quality assessment and processing method based on satellite constellations. This method proposes a comprehensive quality assessment index system for optical satellite constellations based on payload observation capability and orbital coverage capability analysis. It adds assessment indicators reflecting the relationships between satellite constellations, optimizes the calculation strategies for each index when the satellite constellation is considered as a whole, and then adds geometric radiation quality consistency processing considering multi-temporal satellite constellations before basic index preprocessing. This method makes the calculated comprehensive quality performance of the satellite constellation more accurately reflect the overall quality of the satellite constellation, providing accurate data support for satellite use, ground processing, and design feedback.

[0005] The objective of this invention is achieved through the following technical solution: a method for comprehensive quality assessment of optical satellite constellations, comprising the following steps:

[0006] Based on the analysis of satellite constellation characteristics and satellite reconnaissance missions, a suitable comprehensive quality evaluation index system for optical satellite constellations is selected.

[0007] Based on the established comprehensive quality assessment index system for optical satellite constellations and the definitions of each basic index, calculate the specific values ​​of each basic index;

[0008] Data preprocessing is performed on each basic indicator of the overall quality assessment of the satellite constellation.

[0009] The subjective and objective weighting method is used to calculate the weights of the indicator system;

[0010] The overall quality assessment of the satellite constellation is conducted based on the calculated weights and the preprocessed values ​​of each basic indicator.

[0011] Based on the analysis of satellite constellation characteristics and satellite reconnaissance missions, a suitable comprehensive quality assessment index system for optical satellite constellations is selected, including inherent observation capabilities and mission observation capabilities. The inherent observation capabilities are payload observation capabilities, and the mission observation capabilities are orbital coverage capabilities. Furthermore, the comprehensive quality assessment of optical satellite constellations is conducted from the perspectives of radiation domain, geometric domain, temporal coverage capability, and spatial coverage capability, thus constructing a four-level comprehensive quality assessment index system for optical reconnaissance satellite constellations.

[0012] The calculation of specific values ​​for each basic indicator, based on the established comprehensive quality assessment index system for optical satellite constellations and the definitions of each basic indicator, includes:

[0013] Based on the definitions of each indicator, the characteristics of the satellite constellation, and the mission, the satellite payload observation capability and orbital coverage capability indicators are calculated separately, taking into account the satellite constellation as a whole.

[0014] The satellite payload observation capabilities are static indicators, including MTF, signal-to-noise ratio, absolute radiometric calibration accuracy, relative radiometric calibration accuracy in the radiometric domain, and geometric positioning accuracy, length distortion, and inter-spectral registration accuracy in the geometric domain. After calculating the indicator values ​​for individual satellites, a geometric radiometric consistency evaluation indicator was added to reflect the multi-satellite correlation between constellations, and the maximum, minimum, average, and consistency evaluation of the constellations were calculated respectively.

[0015] The orbital coverage capability index is a dynamic index, which includes the revisit cycle of temporal coverage capability, the acquisition time of regional target groups, the duration of continuous target tracking, the daily cumulative number of targets acquired, and the coverage area and regional coverage percentage of spatial coverage capability. The evaluation results of each index are related to the specific tasks involved. The calculation of each index of the orbital coverage capability of the constellation focuses on the overlap of capabilities between constellations and the relay expansion situation, and calculates the maximum capability, minimum capability and average capability of the constellation respectively.

[0016] The MTF metric calculation process is as follows:

[0017] The ratio of the modulation depth of the output signal to the modulation depth of the input signal for different spatial frequencies of a remote sensor

[0018] MTF max =max{MTF i}, i = 1, 2...n

[0019] MTF min =min{MTF i}, i = 1, 2...n

[0020]

[0021]

[0022] Each indicator is represented by its maximum capability (index: max), minimum capability (index: min), average capability (index: mean), and consistency assessment (index: cov); n is the number of satellites in the constellation, and MTF is... i For each satellite, the MTF index, and Represents the pixel value of the reference satellite. and Indicates the pixel values ​​of the compared satellites;

[0023] The calculation of other satellite payload observation capability indicators is similar to the MTF calculation process.

[0024] The track coverage capability index is a dynamic index. The calculation process is as follows, with each index represented by the maximum capability (index: max), the minimum capability (index: min), and the average capability (index: mean).

[0025] Revisit period: The time difference T between two visits by any satellite in a satellite constellation to a certain target. c

[0026]

[0027]

[0028]

[0029] in, The time of the (i+1)th visit of a satellite constellation to a target, sorted in ascending order, is represented by satellite s; T i t Let t be the time of the i-th visit of the satellite constellation to a certain target, and let t be the visited satellite; m is the total number of visits of the satellite constellation to the target, and n is the number of satellites;

[0030] Regional target group acquisition time: The shortest time T required for a satellite constellation to achieve complete coverage of a certain regional target or target group twice. t

[0031]

[0032]

[0033]

[0034] Considering the scenario of multi-satellite relay coverage, among which This represents the maximum time that satellite s can complete its mission to access targets in the region during the i-th regional coverage process. Let m represent the minimum start time of satellite mission t during the i-th regional coverage process, m be the total number of visits to the target by the satellite constellation, and n be the number of satellites.

[0035] Target tracking duration: The duration T during which any satellite in a satellite constellation tracks a target from the start to the end of the tracking process. wt

[0036]

[0037]

[0038]

[0039] but,

[0040]

[0041]

[0042] The scenario of multiple stars continuously accessing the site needs to be considered, among which... Let be the end time of satellite s's i-th visit to a certain target. Let be the start time of satellite t's i-th visit to the target. Let be the duration of satellite s's continuous tracking of the target during its i-th visit. Let t be the duration of satellite t's (i+1)th continuous tracking of the target. To account for the duration of continuous tracking of the nth visit of the constellation to the target after relay processing, m is the total number of visits after processing;

[0043] Daily cumulative target acquisition count: E - Number of targets accessible by the satellite constellation within a day d

[0044]

[0045]

[0046]

[0047]

[0048] Where: N s The number of targets that satellite s can access in a day. The cumulative target number of constellations acquired on day i is n, where n is the number of satellites and m is the number of days in the scenario.

[0049] Coverage area: The single-view imaging coverage area A of a satellite constellation during a single overpass. sat

[0050]

[0051]

[0052]

[0053] in, Let n be the area that satellite j can cover, and n be the number of satellites in the constellation.

[0054] Area coverage percentage: The percentage of the total area that can be covered by a satellite constellation in a single transit. sc

[0055]

[0056] but,

[0057]

[0058]

[0059] in, Let A be the sum of the coverage areas of the satellite constellation at the i-th transit time. objct The area of ​​the target region. represents the regional coverage percentage of the satellite constellation at the time of the i-th transit, and m represents the total number of transits.

[0060] The consistency assessment indexes should be based on the index results of the same ground feature at the same time and after atmospheric correction, BRDF correction and topographic correction, and the correlation of the results of multiple stars in the constellation should be analyzed.

[0061] The data preprocessing includes standardizing the basic indicators by quantitative indicators, and preprocessing them to the range of [0,1] according to cost type and benefit type.

[0062] The method of calculating the weights of the indicator system using subjective and objective weighting methods includes using a combination of subjective and objective methods to calculate the weights of the indicator system, including a combination of principal component analysis and entropy method.

[0063] The comprehensive quality assessment of the satellite constellation is conducted using either the fuzzy comprehensive method or the grey relational analysis method.

[0064] The advantages of this invention compared to the prior art are:

[0065] (1) This invention proposes an integrated quality evaluation index system for optical satellite constellations based on the analysis of payload observation capability and orbital coverage capability. Based on the overall quality effectiveness of the satellite constellation, it comprehensively considers the inherent attributes between satellites and the dynamic changes of attributes between missions. The index calculation algorithm of the integrated quality evaluation index system for satellite constellations designed effectively improves the accuracy of satellite constellation quality evaluation and is closer to the overall quality effectiveness of the satellite constellation.

[0066] (2) By adding constellation consistency evaluation index, this invention effectively overcomes the problem of using the best quality index of a single star to replace the overall satellite constellation performance, and can effectively reflect the comprehensive quality performance of the satellite constellation and multiple stars within the constellation. Attached Figure Description

[0067] Figure 1 This is a flowchart of the method of the present invention.

[0068] Figure 2 This is a schematic diagram of the comprehensive quality assessment index system for optical reconnaissance satellite constellations. Detailed Implementation

[0069] The following is in conjunction with the appendix Figure 1 , 2 The specific embodiments of the present invention will be described in further detail below, and the main steps are as follows:

[0070] (1) Based on the satellite constellation characteristics and satellite reconnaissance missions, suitable comprehensive quality assessment indicators for the satellite constellation are selected. The comprehensive quality assessment of the optical reconnaissance satellite constellation includes inherent observation capabilities and mission observation capabilities. The inherent observation capabilities mainly refer to payload observation capabilities, while the mission observation capabilities mainly consider orbital coverage capabilities. The constructed comprehensive quality assessment indicator system for the optical reconnaissance satellite constellation is as follows, which comprehensively assesses the quality of the optical satellite constellation from the perspectives of radiation domain, geometric domain, temporal coverage capability, and spatial coverage capability.

[0071] (2) Calculate the specific values ​​of each basic indicator based on the established satellite constellation comprehensive quality assessment index system.

[0072] Based on the definitions of each indicator, the characteristics of the satellite constellation, and the mission analysis, and considering the satellite constellation as a whole, the payload observation capability and orbital coverage capability indicators are calculated separately.

[0073] 1) Payload observation capabilities are static indicators, including MTF, signal-to-noise ratio, absolute radiometric calibration accuracy, relative radiometric calibration accuracy in the radiometric domain, and geometric positioning accuracy, length distortion, and inter-spectral registration accuracy in the geometric domain. After calculating the indicator values ​​for a single satellite, the maximum, minimum, and average capabilities of the constellation, as well as the indicator consistency evaluation, are calculated. The indicator consistency evaluation must be conducted on the same ground feature at the same time, after processing with atmospheric correction, BRDF correction, and topographic correction, analyzing the correlation between the results of multiple satellites within the constellation. Taking MTF as an example, the calculation of other satellite payload observation capability indicators is similar, where each indicator is represented by the subscripts: maximum capability (max), minimum capability (min), average capability (mean), and consistency evaluation (cov).

[0074] MTF: Modulation Transfer Function, the ratio of the modulation depth of the output signal to the modulation depth of the input signal for different spatial frequencies by a remote sensor.

[0075] MTF max =max{MTF i}, i = 1, 2...n

[0076] MTF min =min{MTF i}, i = 1, 2...n

[0077]

[0078]

[0079] Where n is the number of satellites in the constellation, MTF i For each satellite, the MTF index, and Represents the pixel value of the reference satellite. and This indicates the pixel value of the compared satellite.

[0080] 2) Orbital coverage capability indicators are dynamic indicators, including the revisit cycle of temporal coverage capability, the acquisition time of regional target groups, the duration of continuous target tracking, the daily cumulative number of targets acquired, and the coverage area and regional coverage percentage of spatial coverage capability. The evaluation results of each indicator are related to the specific tasks involved. The calculation of each indicator for the orbital coverage capability of a constellation needs to focus on the overlap and relay expansion of capabilities between constellations. Generally, they are represented by the constellation's maximum capability, minimum capability, and average capability, respectively. The specific definitions and calculation methods are as follows:

[0081] Revisit period: The time difference T between two visits by any satellite in a satellite constellation to a certain target. c

[0082]

[0083]

[0084]

[0085] in, The time of the (i+1)th visit of a satellite constellation to a target, sorted in ascending order, is represented by satellite s; T i t Let t be the time of the i-th visit of the satellite constellation to a certain target, and let t be the visiting satellite; m is the total number of visits of the satellite constellation to the target, and n is the number of satellites.

[0086] Regional target group acquisition time: The shortest time T required for a satellite constellation to achieve complete coverage of a certain regional target or target group twice. t

[0087]

[0088]

[0089]

[0090] Considering the scenario of multi-satellite relay coverage, among which This represents the maximum time that satellite s can complete its mission to access targets in the region during the i-th regional coverage process. Let m represent the minimum start time of satellite mission t during the i-th regional coverage process, m be the total number of visits to the target by the satellite constellation, and n be the number of satellites.

[0091] Target tracking duration: The duration T during which any satellite in a satellite constellation tracks a target from the start to the end of tracking. wt

[0092]

[0093]

[0094]

[0095] but,

[0096]

[0097]

[0098] The scenario of multiple stars continuously accessing the site needs to be considered, among which... Let be the end time of satellite s's i-th visit to a certain target. Let be the start time of satellite t's i-th visit to the target. Let be the duration of satellite s's continuous tracking of the target during its i-th visit. Let t be the duration of satellite t's (i+1)th continuous tracking of the target. To account for the duration of continuous tracking of the nth visit of the constellation to the target after relay processing, m is the total number of visits after processing.

[0099] Daily cumulative target acquisition count: E - Number of targets accessible by the satellite constellation within a day d

[0100]

[0101]

[0102]

[0103]

[0104] Where: N s The number of targets that satellite s can access in a day. Let n be the cumulative target number of constellations acquired on day i, n be the number of satellites, and m be the number of days in the scene.

[0105] Coverage area: The single-view imaging coverage area A of a satellite constellation during a single overpass. sat

[0106]

[0107]

[0108]

[0109] in, Let n be the area that satellite j can cover, and n be the number of satellites in the constellation.

[0110] Area coverage percentage: The percentage of the total area that can be covered by a satellite constellation in a single transit. sc

[0111]

[0112] but,

[0113]

[0114]

[0115] in, Let A be the sum of the coverage areas of the satellite constellation at the i-th transit time. objct The area of ​​the target region. represents the regional coverage percentage of the satellite constellation at the time of the i-th transit, and m represents the total number of transits.

[0116] (3) Perform data preprocessing on each basic indicator of the processed satellite constellation comprehensive quality assessment.

[0117] Due to differences in the dimensions, range of variation, and expected values ​​of different indicators, they cannot be directly compared and require preprocessing. Basic indicators are preprocessed to the range [0,1] by standardizing them according to their type, such as cost-based and benefit-based indicators.

[0118] (4) The subjective and objective weighting method is used to calculate the weights of the indicator system.

[0119] The weights of the indicator system are calculated using a combination of subjective and objective methods, typically including a combination of principal component analysis and entropy methods. The weights of each basic indicator should meet the following requirements:

[0120]

[0121] Where C ij Let be the weight of the j-th indicator in the i-th layer, and n be the number of indicators in the i-th layer.

[0122] (5) Conduct a comprehensive quality assessment and analysis of the satellite constellation based on the calculated weights and the preprocessed values ​​of each basic indicator.

[0123] The comprehensive quality assessment and analysis of the satellite constellation is carried out based on the calculated weights and preprocessed basic index values, generally including fuzzy comprehensive method, grey relational method, etc.

[0124] The technical solution of this invention addresses the application requirements of the comprehensive quality assessment mission for optical reconnaissance satellite constellations. It constructs a comprehensive quality assessment index system for satellite systems and calculation methods for each index based on the satellite constellation, providing a basic analytical tool for the comprehensive quality assessment of satellite systems.

[0125] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for comprehensive quality assessment of an optical satellite constellation, characterized in that, include: Based on the analysis of satellite constellation characteristics and satellite reconnaissance missions, a suitable comprehensive quality evaluation index system for optical satellite constellations is selected. Based on the established comprehensive quality assessment index system for optical satellite constellations and the definitions of each basic index, calculate the specific values ​​of each basic index; Data preprocessing is performed on each basic indicator of the overall quality assessment of the satellite constellation. The subjective and objective weighting method is used to calculate the weights of the indicator system; The overall quality assessment of the satellite constellation is conducted based on the calculated weights and the preprocessed values ​​of each basic indicator. The analysis is based on the characteristics of the satellite constellation and the satellite reconnaissance mission, and a suitable comprehensive quality evaluation index system for the optical satellite constellation is selected, including inherent observation capabilities and mission observation capabilities. The inherent observation capability is the payload observation capability, and the mission observation capability is the orbital coverage capability. Furthermore, a comprehensive quality assessment of the optical satellite constellation is conducted from the perspectives of radiation domain, geometric domain, temporal coverage capability, and spatial coverage capability, and a four-level comprehensive quality assessment index system for the optical satellite constellation is constructed. The calculation of specific values ​​for each basic indicator, based on the established comprehensive quality assessment index system for optical satellite constellations and the definitions of each basic indicator, includes: Based on the definitions of each indicator, the characteristics of the satellite constellation, and the mission, the satellite payload observation capability and orbital coverage capability indicators are calculated separately, taking into account the satellite constellation as a whole. The satellite payload observation capabilities are static indicators, including MTF, signal-to-noise ratio, absolute radiometric calibration accuracy, relative radiometric calibration accuracy in the radiometric domain, and geometric positioning accuracy, length distortion, and inter-spectral registration accuracy in the geometric domain. After calculating the indicator values ​​for individual satellites, a geometric radiometric consistency evaluation indicator was added to reflect the multi-satellite correlation between constellations, and the maximum, minimum, average, and consistency evaluation of the constellations were calculated respectively. The orbital coverage capability index is a dynamic index, which includes the revisit cycle of temporal coverage capability, the acquisition time of regional target groups, the duration of continuous target tracking, the daily cumulative number of targets acquired, and the coverage area and regional coverage percentage of spatial coverage capability. The evaluation results of each index are related to the specific tasks involved. The calculation of each index of the orbital coverage capability of the constellation focuses on the overlap of capabilities between constellations and the relay expansion situation, and calculates the maximum capability, minimum capability and average capability of the constellation respectively.

2. The method for comprehensive quality assessment of an optical satellite constellation as described in claim 1, characterized in that: The consistency assessment indexes should be based on the index results of the same ground feature at the same time and after atmospheric correction, BRDF correction and topographic correction, and the correlation of the results of multiple stars in the constellation should be analyzed.

3. The method for comprehensive quality assessment of an optical satellite constellation as described in claim 1, characterized in that: The data preprocessing includes standardizing the basic indicators by quantitative indicators, and preprocessing them to the range of [0,1] according to cost type and benefit type.

4. The method for comprehensive quality assessment of an optical satellite constellation as described in claim 1, characterized in that: The subjective and objective weighting method is used to calculate the weights of the indicator system. This includes using a combination of subjective and objective methods to calculate the weights of the indicator system, including a combination of principal component analysis and entropy analysis.

5. The method for comprehensive quality assessment of an optical satellite constellation as described in claim 1, characterized in that: The comprehensive quality assessment of the satellite constellation is conducted using either the fuzzy comprehensive method or the grey relational analysis method.

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