fix: Improve GPS position retrieval with error handling and retry logic

turtle.lua

@@ -555,12 +555,35 @@ end
 
 -- Main loop
 print("Initializing...")
-updatePosition()
+print("Checking for wireless modem...")
+if not modem then
+    print("ERROR: Wireless modem not found!")
+else
+    print("Wireless modem: OK")
+end
+
+print("Attempting to get GPS position (this may take 10 seconds)...")
+local gpsAttempts = 0
+local maxGpsAttempts = 3
+
+while not state.position and gpsAttempts < maxGpsAttempts do
+    gpsAttempts = gpsAttempts + 1
+    print("GPS attempt " .. gpsAttempts .. " of " .. maxGpsAttempts .. "...")
+    updatePosition()
+    if not state.position then
+        print("Waiting 2 seconds before retry...")
+        sleep(2)
+    end
+end
+
 updateFuel()
 
 if not state.position then
-    print("WARNING: No GPS signal!")
-    print("Limited functionality available")
+    print("WARNING: No GPS signal after " .. maxGpsAttempts .. " attempts!")
+    print("Make sure GPS hosts are set up correctly.")
+    print("Limited functionality available - position tracking disabled.")
+else
+    print("GPS: OK - Position acquired!")
 end
 
 print("Ready! Waiting for commands...")