From bdc0f1537fd43b8314d985b3f86910e57323b412 Mon Sep 17 00:00:00 2001
From: Mauricio Gomes <mauricio@edge14.com>
Date: Wed, 2 Sep 2026 22:23:02 -0400
Subject: [PATCH] Telemetry: say which altitude gps_alt is

---
 docs/notes/Telemetry.md | 2 +-
 src/telemetry.rs        | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/docs/notes/Telemetry.md b/docs/notes/Telemetry.md
index 4721ea7..fd78d75 100644
--- a/docs/notes/Telemetry.md
+++ b/docs/notes/Telemetry.md
@@ -11,7 +11,7 @@ the dashboard indexes by position, not by name. #telemetry #downlink
 | 3 | `imu_ax`      | m/s² | ±50          |
 | 4 | `imu_ay`      | m/s² | ±50          |
 | 5 | `imu_az`      | m/s² | ±50          |
-| 6 | `gps_alt`     | m    | 0 – 400 000  |
+| 6 | `gps_alt`     | m    | 0 – 400 000 (above the ellipsoid) |
 | 7 | `gps_vel`     | m/s  | 0 – 8 000    |
 | 8 | `bat_v`       | V    | 24 – 30      |
 | 9 | `fts_arm`     | bool |              |
diff --git a/src/telemetry.rs b/src/telemetry.rs
index ad12da9..c8b4187 100644
--- a/src/telemetry.rs
+++ b/src/telemetry.rs
@@ -7,8 +7,9 @@ pub struct Frame {
     pub chamber_pressure: f64,
     /// Oxidizer tank ullage pressure in bar.
     pub lox_pressure: f64,
-    /// Main bus voltage.
+    /// Main bus voltage in volts.
     pub battery_v: f64,
+    /// GPS altitude above the ellipsoid in metres.
     pub altitude_m: f64,
 }