gps related minor fixes

pi/backend/gps_service.py

@@ -45,6 +45,7 @@ class GPSService:
 
         # Periodic status logging
         self._last_status_log = 0.0
+        self._last_state_emit = 0.0
         self._fix_count = 0
 
     def set_on_data(self, callback):
@@ -165,11 +166,20 @@ class GPSService:
                         timeout_s = "120s" if not self._has_ever_fixed else "10s"
                         print(f"[GPS] No GPS fix after {timeout_s}, will retry connection")
                         raise ConnectionError("No GPS fix within timeout")
+                    # Emit state periodically so UI knows we're alive
+                    now = time.time()
+                    if now - self._last_state_emit >= 5.0:
+                        self._last_state_emit = now
+                        with self._lock:
+                            self._latest = fix
+                        if self._on_data_callback:
+                            self._on_data_callback(fix)
                     continue  # Skip empty fixes
 
                 # Got real data — mark first fix, reset timeout to shorter window
                 if not self._has_ever_fixed:
                     self._has_ever_fixed = True
+                    self._last_state_emit = 0.0  # Force immediate emit on transition
                     print("[GPS] First fix acquired")
                 fix_timeout = time.time() + 10.0  # 10s timeout for signal loss
 

pi/backend/main.py

@@ -140,6 +140,10 @@ def on_arduino_data(data):
     data = dict(data)  # Don't mutate original
     data["theme_switch"] = gpio.theme_switch
     
+    # backend voltage offset correction
+    if "voltage" in data:
+        data["voltage"] += 0.2  # Calibration offset
+
     def emit_fn(d):
         socketio.emit("arduino", d)
 

pi/ui/lib/widgets/gps_compass.dart

@@ -61,7 +61,7 @@ class GpsCompass extends StatelessWidget {
               _hasSignal ? "${_displayHeading} ${_compassDirection}" : (_isAcquiring ? "ACQ" : "N/A"),
               style: TextStyle(
                 fontSize: 80,
-                color: theme.subdued,
+                color: theme.subdued, // less emphasis on text, let the icon have semantic colour
                 fontFamily: 'DIN1451',
               ),
             ),

pi/ui/lib/widgets/system_bar.dart

@@ -70,7 +70,7 @@ class SystemBar extends StatelessWidget {
                   value: gpsState == 'acquiring' ? 'ACQ'
                        : gpsState == 'fix' ? (gpsSatellites?.toString() ?? 'N/A')
                        : '0',  // lost or unknown
-                  isAbnormal: gpsState != 'fix',
+                  isAbnormal: gpsState != 'fix' || gpsSatellites == null,
                   alignment: Alignment.centerLeft,
                   labelSize: labelSize,
                   valueSize: valueSize,