We Do Space Research.

# 问题

• 学习 attitude estimation 算法
• QUEST

Again, I run into the question that “what’s the difference between GP and GPs”? Here, GP is Gaussian process while GPs is Gaussian processes. So you see the difference?

In this post, I decided to solve this confusion (a better words? puzzle? bewilderment? perplexity?) once and for all.

# Call-for-abstract Open

Conjunction Analysis
satellite orbital conjunction
NOT conjuncture analysis !

In practice, not in the practice.

successively v.s. consecutively

start v.s. conduct

This is some collections and summaries of TLE-related papers in my Zotero collection. Questions and discussions are welcomed.

Publications summarized here are all worth studying.

(Some notes are in Chinese.)

# DTM2000

See Orekit implementation here.

It is described in the paper:

The DTM-2000 empirical thermosphere model with new data assimilation and constraints at lower boundary: accuracy and properties S. Bruinsma, G. Thuillier and F. Barlier
Journal of Atmospheric and Solar-Terrestrial Physics 65 (2003) 1053–1070

This model provides dense output for altitudes beyond 120 km.

The model needs geographical and time information to compute general values, but also needs space weather data : mean and instantaneous solar flux and geomagnetic indices.

Mean solar flux is (for the moment) represented by the F10.7 indices. Instantaneous flux can be set to the mean value if the data is not available. Geomagnetic activity is represented by the Kp indice, which goes from 1 (very low activity) to 9 (high activity).

All these data can be found on the NOAA (National Oceanic and Atmospheric Administration) website.

USNavalResearchLaboratory/TrackerComponentLibrary at GitHub

The Tracker Component Library is a collection of Matlab routines for simulating and tracking targets in various scenarios. Due to the complexity of the target tracking problem, a great many routines can find use in other areas including combinatorics, astronomy, and statistics.

Recently, I ran into a very comprehensive MATLAB repository, which is very rare to my knowledge. Usually people find comprehensive packages in other languages, like Orekit in Java, GMAT in C++, many others in Python, and even one in Julia.
So, I decide to have a look at it and take nots here.