mirror of https://github.com/gnss-sdr/gnss-sdr synced 2026-01-30 06:40:19 +00:00

Files

Carles Fernandez 9cf944b8f8 skyplot: more improvements:

Add reading of RINEX 4 navigation files
More robust finding of RINEX obs files when --use-obs is set
Add type hints to some functions for improved documentation and readability
Improve reading of RINEX obs files
Make labels more transparent and colorful
Update documentation

2025-08-23 15:53:28 +02:00

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GNSS Skyplot utility

A Python script that generates polar skyplots from RINEX navigation files, showing satellite visibility over time.

Features

Processes RINEX navigation files.
Calculates satellite positions using broadcast ephemeris.
Plots satellite tracks in azimuth-elevation coordinates.
Customizable observer location.
Color-codes satellites by constellation (GPS, Galileo, GLONASS, BeiDou).
Elevation mask set to 5°, configurable via the --elev-mask optional argument.
Outputs high-quality image in PDF format. EPS, PNG, and SVG formats are also available via the --format optional argument.
Non-interactive mode for CI jobs with the --no-show optional argument.
Constellations to plot can be configured via the --system optional argument.
Optionally, it uses the corresponding RINEX observation file to limit the plot to the receiver observation time via the--use-obs optional argument.
- If this argument is set, the tool looks for a matching file following standard RINEX naming conventions, and uses it if found.

Requirements

Python 3.6+
Required packages:
- numpy
- matplotlib

Usage

Basic Command

./skyplot.py <RINEX_FILE> [LATITUDE] [LONGITUDE] [ALTITUDE]
             [--elev-mask ELEV_MASK]
             [--format {pdf,eps,png,svg}]
             [--no-show]
             [--system SYSTEM [SYSTEM ...]]
             [--use-obs]

Arguments

Argument	Type	Units	Description	Default
`RINEX_NAV_FILE`	Required	-	RINEX nav file path	-
`LATITUDE`	Optional	degrees (°)	North/South position	41.275°N
`LONGITUDE`	Optional	degrees (°)	East/West position	1.9876°E
`ALTITUDE`	Optional	meters (m)	Height above sea level	80.0 m
`--elev-mask`	Optional	degrees (°)	Elevation mask	5°
`--format`	Optional	-	Output {pdf,eps,png,svg}	pdf
`--no-show`	Optional	-	Do not show plot	-
`--system`	Optional	-	Systems to plot	All
`--use-obs`	Optional	-	Use RINEX obs data	-

Examples

Skyplot from default location (Castelldefels, Spain):
```
./skyplot.py brdc0010.22n
```
Skyplot from custom location (New York City, USA):
```
./skyplot.py brdc0010.22n 40.7128 -74.0060 10.0
```
Skyplot from custom location (Santiago, Chile) using receiver observation time:
```
./skyplot.py brdc0010.22n -33.4592 -70.6453 520.0 --use-obs
```

Non-interactive mode (for CI jobs):

./skyplot.py brdc0010.22n -33.4592 -70.6453 520.0 --no-show

Only plot GPS and Galileo satellites:

./skyplot.py brdc0010.22n -33.4592 -70.6453 520.0 --system GPS Galileo

./skyplot.py brdc0010.22n -33.4592 -70.6453 520.0 --system G E

Get a PNG file:

./skyplot.py brdc0010.22n -33.4592 -70.6453 520.0 --format png

Output

The script generates a PDF file named skyplot_<RINEX_FILE>.pdf (with dots in <RINEX_FILE> replaced by _) with:

Satellite trajectories over all epochs in the file.
- NAV file - ephemeris time range (default).
- Receiver observation time if --use-obs is specified and the RINEX OBS file is found.
Color-coded by constellation.
Observer location in title.
Time range in footer.
Embedded fonts that display consistently across all systems and generate publication-ready figures.
EPS, PNG, and SVG output formats available via --format eps, --format png, and --format svg.

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