Calibration of atmospheric density model using two-line element data

Ren, Yuan; Shan, Jinjun

doi:10.1007/s42064-017-0008-3

Cited by 3 publications

(3 citation statements)

References 13 publications

(16 reference statements)

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“…Where φ = ω+M, ω is the argument of perigee, and M is the mean anomaly. The above equation implies that the variety of semi-major axis cause the variety of phase relative to the perigee (Yang et al 2016;Ren and Shan 2018). Considering the semi-major axis and the inclination have perturbations with the change of time, let…”

Section: Motion Equationmentioning

confidence: 99%

Evolution of space debris for spacecraft in the Sun-synchronous orbit

Jiang

Yue³

2020

Open Astronomy

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In this paper, the evolution of space debris for spacecraft in the Sun-Synchronous orbit has been investigated. The impact motion, the evolution of debris from the Sun-Synchronous orbit, as well as the evolution of debris clouds from the quasi-Sun-Synchronous orbit have been studied. The formulas to calculate the evolution of debris objects have been derived. The relative relationships of the velocity error and the rate of change of the right ascension of the ascending node have been presented. Three debris objects with different orbital parameters have been selected to investigate the evolution of space debris caused by the Sun-Synchronous orbit. The debris objects may stay in quasi-Sun-Synchronous orbits or non-Sun-Synchronous orbits, which depend on the initial velocity errors of these objects.

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Section: Motion Equationmentioning

confidence: 99%

Evolution of space debris for spacecraft in the Sun-synchronous orbit

Jiang

Yue³

2020

Open Astronomy

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“…Stiffness optimization is mainly based on the three muscle states of stroke patients [54], who have special muscle characteristics in different periods and requires the specific muscle exercises listed in Table 1 [55]- [59]. During the active separation period, the muscle stiffness is proportional to the port stiffness; during the spasm period, the muscle stiffness is inversely proportional to the port stiffness; during the soft period, there is a force boundary point.…”

Section: ) Stabilitymentioning

confidence: 99%

Stiffness Adjustment for a Single-Link Robot Arm Driven by Series Elastic Actuator in Muscle Training

Tian

et al. 2019

IEEE Access

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Series elastic actuators (SEAs) can improve the performance of robots and ensure their safety; therefore, they are widely applied in rehabilitation robots. To effectively exercise muscles in late rehabilitation training, robots utilize different impedance characteristics according to human muscle conditions. In this study, a novel real-time parallel variable-stiffness control method is proposed. The method predicts the muscle stiffness of the human body during the interaction process, and then adjusts the port stiffness of the SEA as needed to improve strength training. The impedance controller is used to meet the port stiffness and stability requirements during interactions. The predictive stiffness control method not only assesses the stiffness of human muscles in real time but also meets the constraint conditions associated with interaction stability, speed, and position. This control structure enables effective and safe strength training. Finally, the experimental results indicate that the stiffness control method based on muscle stiffness prediction can accurately match the port stiffness and provide interaction stability for effective muscle exercise.INDEX TERMS Series elastic actuator, stiffness predictive algorithm, rehabilitation interactive design.

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“…By assimilating observed density data to estimate model parameter corrections, the process that called density model calibration is able to effectively improve model accuracy. Many studies have been carried out on the calibration method, such as high accuracy satellite drag model (HASDM) (Storz et al, 2005), parameterization method (Doornbos et al, 2005;Doornbos, 2012), the scale calibration (Shi et al, 2015;Ren and Shan, 2018), the neural network-based calibration (Perez and Bevilacqua, 2015) and the inter-calibration approach (Weimer et al, 2016). Significant progress has already been made on the HASDM and the research presented by Doornbos. In HASDM, a weighted least-squares algorithm, which is called dynamic calibration atmosphere (DCA) (Casali and Barker, 2002), is used to estimate the corrections of satellite states and Jacchia-70 density model parameters.…”

Section: Introductionmentioning

confidence: 99%

The application of nonlinear least-squares estimation algorithms in atmospheric density model calibration

Zhang

Duan

et al. 2020

AEAT

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Purpose The purpose of this paper is to focus on the performance of three typical nonlinear least-squares estimation algorithms in atmospheric density model calibration. Design/methodology/approach The error of Jacchia-Roberts atmospheric density model is expressed as an objective function about temperature parameters. The estimation of parameter corrections is a typical nonlinear least-squares problem. Three algorithms for nonlinear least-squares problems, Gauss–Newton (G-N), damped Gauss–Newton (damped G-N) and Levenberg–Marquardt (L-M) algorithms, are adopted to estimate temperature parameter corrections of Jacchia-Roberts for model calibration. Findings The results show that G-N algorithm is not convergent at some sampling points. The main reason is the nonlinear relationship between Jacchia-Roberts and its temperature parameters. Damped G-N and L-M algorithms are both convergent at all sampling points. G-N, damped G-N and L-M algorithms reduce the root mean square error of Jacchia-Roberts from 20.4% to 9.3%, 9.4% and 9.4%, respectively. The average iterations of G-N, damped G-N and L-M algorithms are 3.0, 2.8 and 2.9, respectively. Practical implications This study is expected to provide a guidance for the selection of nonlinear least-squares estimation methods in atmospheric density model calibration. Originality/value The study analyses the performance of three typical nonlinear least-squares estimation methods in the calibration of atmospheric density model. The non-convergent phenomenon of G-N algorithm is discovered and explained. Damped G-N and L-M algorithms are more suitable for the nonlinear least-squares problems in model calibration than G-N algorithm and the first two algorithms have slightly fewer iterations.

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Calibration of atmospheric density model using two-line element data

Cited by 3 publications

References 13 publications

Evolution of space debris for spacecraft in the Sun-synchronous orbit

Evolution of space debris for spacecraft in the Sun-synchronous orbit

Stiffness Adjustment for a Single-Link Robot Arm Driven by Series Elastic Actuator in Muscle Training

The application of nonlinear least-squares estimation algorithms in atmospheric density model calibration

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