  Micro aerial vehicles (MAVs) have high potential for information gathering
tasks to support situation awareness in search and rescue scenarios. Manually
controlling MAVs in such scenarios requires experienced pilots and is
error-prone, especially in stressful situations of real emergencies. The
conditions of disaster scenarios are also challenging for autonomous MAV
systems. The environment is usually not known in advance and GNSS might not
always be available.
  We present a system for autonomous MAV flights in unknown environments which
does not rely on global positioning systems. The method is evaluated in
multiple search and rescue scenarios and allows for safe autonomous flights,
even when transitioning between indoor and outdoor areas.
