strf/GUIDE.md

Guide for RF doppler analysis from SatNOGS Observation Waterfall Images

Forum post: https://community.libre.space/t/new-software-satnogs-waterfall-tabulation-helper/4380

This tool evolved from the need to tabulate doppler data from the lunar Change-4 probe, see https://gitlab.com/kerel-fs/jupyter-notebooks/-/tree/master/change4/data#data-tabulation-method-new.

Installation

Install dependencies

pip install -r contrib/requirements.txt

First Setup

Choose a folder where TLEs are stored and a folder where RF doppler observatons (.dat-files) are stored.

For now the paths are configured via environment variables, so make sure to set them correctly before each usage.

Example:

# Filename convention: {TLE_DIR}/{observation_id}.txt
SATNOGS_TLE_DIR="./data/tles"

# absulute frequency measurement storage
# Filename convention: {DOPPLER_OBS_DIR}/{observation_id}.txt
SATNOGS_DOPPLER_OBS_DIR="./data/obs"

# SATTOOLS/STRF/STVID sites.txt file
SATNOGS_SITES_TXT="./data/sites.txt"

mkdir -p $SATNOGS_TLE_DIR
mkdir -p $SATNOGS_DOPPLER_OBS_DIR

Usage

0. Make sure the (3) env variables are set.

1. Choose SatNOGS Observation ID from network and run the tabulation helper

   ./contrib/satnogs_waterfall_tabulation_helper.py 1102230
   

   An interactive plot will show up. Clicking inside the plot will add a signal marker. If you are finished with adding signal markers, save the signal markers using the keyboard shortcut f.

   Custom keyboard shortcuts:

   • u - undo last signal marker
     

   • f - save the signal markers in an strf-compatible file
     

   Useful Matplotlib navigation keyboard shortcuts (documentation):

   p - toggle 'Pan/Zoom' modus
   o - toggle 'Zoom-to-rect' modus
   h - Home/Reset (view)
   c - Back (view)
   

2. Run rffit for orbit fitting, e.g.

   ./rffit -d $SATNOGS_DOPPLER_OBS_DIR/1102230.dat -i 44356 -c $SATNOGS_TLE_DIR/1102230.txt -s 7669
   

Known issues

• A site id of the form 7{station_id} is automatically assigned and written to the sites.txt (e.g. station 669 should get 7669 assigned). Only SatNOGS stations <999 are supported, as the strf sites.txt parse only allows 4-digit site ids. In case of problems, choose a free site id and manually correct the doppler obs (.dat-files, last colum).