# Summary of High Area-to-Mass Ratio (HAMR)

## brack_inorbit_2017

In-Orbit Tracking of High Area-to-Mass Ratio Space Objects

这篇的intro介绍了许多新内容，值得学习

## Singla, Puneet. 2016. “Certain Thoughts on Uncertainty Analysis for Dynamical Systems.” Department of Mechanical and Aerospace Engineering, University of Texas at Arlington, August 17. http://lairs.eng.buffalo.edu/wiki/images/a/ac/SinglaTalk.pdf.

The fusion of observational data with numerical simulation promises to provide greater understanding of physical phenomenon than either approach alone can achieve.

The most critical challenge here is to provide a quantitative assessment of how closely our estimates reflect reality in the presence of model uncertainty as well as measurement errors and uncertainty.

Uncertainty Propagation: Nonlinear Systems

- Approximate Solution to exact problem: Multiple-model estimation method, Unscented Kalman Filter (UKF), Monte Carlo (MC) methods.
- Exact solution to approximate problem: Extended Kalman Filter (EKF), Gaussian closure, Stochastic Linearization…

这两者的区别在哪里？为什么EKF是exact solution？

**Fokker-Planck-Kolmogorov equation (FPKE)**

With sufficient number of Gaussian components, any pdf can be approximated as closely as desired.