diff --git a/CoLo-AT/robots/robot_system.py b/CoLo-AT/robots/robot_system.py
index 079d1ad01092564199180c18042ce245a292232c..e072873133ab19e422d0346f8c2dc12760b9ec87 100644
--- a/CoLo-AT/robots/robot_system.py
+++ b/CoLo-AT/robots/robot_system.py
@@ -113,6 +113,7 @@ class RobotSystem:
 					sensor_input = [obser_index, meas_range, bearing, message_data['time'], obj_id]
 				else:
 					update_type = 'invalid observation'
+					print("No measurements for robot:", self.robot_labels[robot_index], " at time:", self.time)
 					valid_update = False
 					sensor_input = None