enferex / satnow

satnow: Collect satellite data and calculate look angles.

satnow: Collect satellite data and calculate look angles.

This is alpha (which is my excuse if something doesn't function accurately or correctly).

satnow is a utility for collecting satellite position information and for displaying satellite look angles. This might be useful for those interested in satellite observation. The list of satellites is presented based on the range from the user's latitude/longitude/altitude. Closer things appear first.

satnow will create a database, by default .satnow.sqlite3, in your current working directory. That database contains all of the collected TLE entries you have specified while updating. You can override the default by using the --db command line option.

satnow works on position information presented in the Two-Line Element (TLE). satnow can download the TLE data or load pre-existing data from a text file on disk.

Usage

If you do not have TLE data, download some! (Use the --update=<source file> option and pass it a path to a file that contains a list of URLs to TLE data). In other words, the file argument to --update is just a newline delimited list of files or URLs that have the actual TLE information. Example: ./satnow --update=sources.txt

When running the tool, pass in your latitude and longitude in decimal degrees: (via the --lat and --lon command line options).

The --update=<source file> command line option is used to retrieve, store, and update satellite position information. This updates the database. The file argument to --update must point to a text file that contains a list of file paths and URLs. Each URL and path must be on its own line. Those paths and URLs contain the actual set of TLE data. For example:

    # Example source file for use with the --update option
    /path/to/TLE.txt  # Some of my favorite TLE data
    /path/to/TLE2.txt # More awesome TLE entries
    http://some.example.com/noaa-tle.txt # A fictitious URL containing TLE data.

The (optional) --gui support is recommended, as it presents the data in a clean manner that is easy to refresh. The refresh of data means re-calculating the satellite look angles at the current time (satellites move quickly so their position changes predictably quick).

Building

1. Create a build directory. mkdir satnow/build
2. From the just created build directory, invoke cmake with the path to the satnow sources. cd satnow/build; cmake ../
3. Invoke make to download and build the libsgp4 dependency, as well as build satnow.

Dependencies

• libsgp4: dnwr's awesome libsgp4 library. This library provides some useful clock and TLE classes, calculates look angles, and performs other positioning magic via the SGP4 model. This library is downloaded and built automatically.
• sqlite3: Database library used for storing the collected TLE information.
• curl: Used to download TLE data from remote sources specfied via a URL.
• ncurses: (Optional) Curses library used to render the --gui mode.

Resources

• https://celestrak.com: Tons of SGP orbital information and updated TLE listings.
• https://tle.info: Another source of TLE data.
• https://space-track.org: US Gov't contract developed site for producing TLE information. Data is provided by the Joint Space Operations Center.
• TLESniff: Much of the frontend of this tool was based on functionality also presented in my TLESniff program. If all you want to do is collect and store TLE data, use that.

Screen Shot

Contact

Matt Davis: https://github.com/enferex