From 25656f5e4c4236b19a2858f966a45f542a1a77b0 Mon Sep 17 00:00:00 2001
From: sl-webui <sl-webui@saltylab.local>
Date: Fri, 3 Apr 2026 22:41:47 -0400
Subject: [PATCH] fix(sultee-tracker): subscribe to proper ROS GPS topics for
 robot marker
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Switch robot GPS subscription from custom saltybot/gps/* std_msgs/String
topics to the canonical /gps/fix (sensor_msgs/NavSatFix) and /gps/vel
(geometry_msgs/TwistStamped) published by the SIM7600X GPS driver node.

- /gps/fix: read msg.latitude/longitude/altitude/status.status directly
- /gps/vel: compute speed (sqrt(vx²+vy²) * 3.6 km/h) and heading
  (angular.z radians → degrees) from ENU velocity components

Closes #709

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 ui/sultee-tracker.html | 58 ++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 30 deletions(-)

diff --git a/ui/sultee-tracker.html b/ui/sultee-tracker.html
index 0d24c74..b6dcfa5 100644
--- a/ui/sultee-tracker.html
+++ b/ui/sultee-tracker.html
@@ -723,43 +723,41 @@ function connectRos(url) {
 }
 
 function setupRobotTopics() {
-  // saltybot/gps/fix — {lat, lon, alt, stat, t}
+  // /gps/fix — sensor_msgs/NavSatFix (SIM7600X / Pixel 5 GPS)
   new ROSLIB.Topic({
-    ros, name: 'saltybot/gps/fix',
-    messageType: 'std_msgs/String', throttle_rate: 500,
+    ros, name: '/gps/fix',
+    messageType: 'sensor_msgs/NavSatFix', throttle_rate: 500,
   }).subscribe(msg => {
-    try {
-      const d = JSON.parse(msg.data);
-      robot.lat  = d.lat  ?? robot.lat;
-      robot.lon  = d.lon  ?? robot.lon;
-      robot.alt  = d.alt  ?? robot.alt;
-      robot.stat = d.stat ?? robot.stat;
-      robot.fixes++;
-      robot.tsfix = Date.now();
+    robot.lat  = msg.latitude  ?? robot.lat;
+    robot.lon  = msg.longitude ?? robot.lon;
+    robot.alt  = msg.altitude  ?? robot.alt;
+    robot.stat = msg.status ? msg.status.status : robot.stat;
+    robot.fixes++;
+    robot.tsfix = Date.now();
 
-      if (robot.lat != null && robot.lon != null) {
-        updateRobotMap(robot.lat, robot.lon, robot.hdg);
-      }
-      $('last-msg').textContent = 'Robot: ' + new Date().toLocaleTimeString('en-US', { hour12: false });
-      render();
-    } catch(_) {}
+    if (robot.lat != null && robot.lon != null) {
+      updateRobotMap(robot.lat, robot.lon, robot.hdg);
+    }
+    $('last-msg').textContent = 'Robot: ' + new Date().toLocaleTimeString('en-US', { hour12: false });
+    render();
   });
 
-  // saltybot/gps/vel — {spd, hdg, t}
+  // /gps/vel — geometry_msgs/TwistStamped (east/north m/s + heading in radians)
   new ROSLIB.Topic({
-    ros, name: 'saltybot/gps/vel',
-    messageType: 'std_msgs/String', throttle_rate: 500,
+    ros, name: '/gps/vel',
+    messageType: 'geometry_msgs/TwistStamped', throttle_rate: 500,
   }).subscribe(msg => {
-    try {
-      const d = JSON.parse(msg.data);
-      robot.spd = d.spd ?? robot.spd;
-      robot.hdg = d.hdg ?? robot.hdg;
-      robot.tsvel = Date.now();
-      if (robotMarker && robot.lat != null) {
-        robotMarker.setIcon(makeRobotIcon(robot.hdg));
-      }
-      render();
-    } catch(_) {}
+    const vx  = msg.twist.linear.x;   // east  m/s
+    const vy  = msg.twist.linear.y;   // north m/s
+    const spd = Math.sqrt(vx * vx + vy * vy) * 3.6; // → km/h
+    const hdg = (msg.twist.angular.z * 180 / Math.PI + 360) % 360; // radians → degrees
+    robot.spd = spd;
+    robot.hdg = hdg;
+    robot.tsvel = Date.now();
+    if (robotMarker && robot.lat != null) {
+      robotMarker.setIcon(makeRobotIcon(robot.hdg));
+    }
+    render();
   });
 }