GPS Constellation Status Screensaver
The GPS Constellation Status screensaver shows the real, current health of every GPS satellite (SV), parsed straight from the US Space Force's Yuma almanac as republished by CelesTrak. Healthy SVs get a green dot, unhealthy ones red, grouped by orbital plane. It's free, needs an internet connection, and ESC exits.
How the GPS Constellation Status screensaver works
Your browser fetches the current Yuma almanac text from CelesTrak (key-less, CORS-enabled) about once an hour.
Each PRN block's Health field is parsed: 000 means healthy, anything else means the satellite is set unhealthy or unusable.
Satellites are grouped into the constellation's six orbital planes by bucketing each SV's right ascension of ascending node from the same almanac.
The headline counts healthy SVs, and the header shows the almanac week it came from.
A worked example
On a typical day the board reads something like '31 of 32 SVs healthy' — six tidy plane rows of green dots with one red chip pulsing, say PRN-13 set unhealthy for maintenance. When the Space Force sets it healthy again, the chip flips back to green on the next hourly refresh. In Multi-view it pairs well with other space boards.
Settings & tips
- Group by orbital plane — on, you get six RAAN-bucketed rows; off, a flat PRN grid.
- Plane letters are assigned in longitude order from the almanac's RAAN values — a close, honest approximation of the official A–F planes.
- The almanac updates about daily, so a fresh outage can take a little while to appear.
Frequently asked questions
- Is this real, live GPS status?
- Yes — it parses the US Space Force's current Yuma almanac, republished by CelesTrak, about once an hour. Health flags are exactly what the almanac publishes.
- Do I need an API key?
- No. The CelesTrak almanac is public, key-less and CORS-enabled, so your browser reads it directly.
- Does it work offline?
- No — it needs an internet connection to fetch the almanac; offline it shows a short notice.
- Is it free?
- Yes — free, no download, runs in your browser.
- What does an unhealthy SV mean?
- A non-zero health code means the Space Force has marked that satellite unusable — often for maintenance or repositioning. GPS receivers ignore it until it's set healthy again.