fix: change coordinate system of simulator and autopilot, reduce approximation error

timer.py

@@ -0,0 +1,31 @@
+import time
+
+class Timer:
+    elapsed: float
+    last_enabled: float
+    enabled: bool
+
+    def __init__(self):
+        self.elapsed = 0.
+        self.enabled = False
+
+    def get_diff(self) -> float:
+        if not self.enabled: return 0.
+        return time.time() - self.last_enabled
+
+    def start(self):
+        if self.enabled: return
+        self.enabled = True
+        self.last_enabled = time.time()
+
+    def stop(self):
+        self.elapsed += self.get_diff()
+        self.enabled = False
+
+    def get_elapsed(self) -> float:
+        return self.elapsed + self.get_diff()
+    
+    def reset(self):
+        self.elapsed = 0.
+        self.enabled = False
+        self.last_enabled = 0.