The estimated remaining time, in seconds, it will take the aircraft to go home with a 10% battery buffer remaining. This time includes landing the aircraft. If the aircraft is using the simulator, this value will be 0.
The maximum radius, in meters, an aircraft can fly from its home location and still make it all the way back home, based on altitude, distance, battery, etc. If the aircraft goes out farther than the max radius, it will fly as far back home as it can and land. If the aircraft is using the simulator, this value will be 0.
The countdown (in seconds) for the Smart Return-To-Home (RTH). Once the countdown reaches 0, the aircraft will execute an automatic go-home procedure. It is only valid when getSmartRTHState is COUNTING_DOWN.