DJI - RTH: How It Works and What to Avoid.

RTH: How It Works and What to Avoid

DJI drones have simple controls, excellent image transmission, and the power to show us the world as it's never been seen before. However, not all of their functions are as intuitive as they seem. Some users have said that the Return to Home function, one of the touchstone functions of our drones, is in fact a button designed to lose your drone. However, this is certainly not the case. The objective of this article is to clear up some misunderstands related to the RTH button.

RTH: Failsafe

This illustration from the manual may look a little complicated. But no worries, let take a closer look.
What are the prerequisites of RTH?
When GPS signal strength is GREATER THAN SIX BARS and you hear the app say "Home Point Recorded."
Please take note of your location. There will also be a green H on the map, which means the Home Point is set and the RTH function is ready to use.

Some users have had accidents after pressing the RTH button, because their drones unexpectedly ascend and crash into something. Therefore, it is essential to understand the logic of the RTH function. Let's have a look of these pictures from the manual:

RTH: Failsafe Safety Notice

There are two '20 meters' mentioned in the pictures above. One of the measurements is altitude and the other is horizontal distance.
If RTH is triggered below an altitude of 20 meters, the aircraft will automatically ascend to 20 meters, since that is the altitude set by default in the app. The drone can't be controlled during ascension. This parameter can be adjusted in Flight Control Settings > Advanced Settings > RTH.The default value is 20 meters, but can be modified it according to the situation.

RTH: Failsafe Settings

Once RTH is pressed, this is what the drone thinks:
"Master is commanding me to return home." (When receiving the RTH command)
"Alright, I'm ascending to the preset RTH altitude! Nothing can stop me from ascending!' (To the predetermined height)
"Ok, now I'm adjusting my nose towards master.' (Adjusts direction)
"I'm on my way back now!" (Returns to the Home Point)
"I'm going to land now!" (Descends after reaching the Home Point)
Please remember that the drone can't be controlled while rising to the RTH altitude!

What is the 20 meters of horizontal distance?

"Aircraft automatically descends and lands if RTH is triggered when the aircraft flies within a 20 meter (65 foot) radius of the Home Point. Aircraft will stop ascending and immediately return to the Home Point if you move the throttle stick if the aircraft reaches 20 meters (65 feet) altitudes or beyond during Failsafe."
When the drone flies within a 20 meters radius of the Home Point and the RTH button is pressed,the aircraft thinks:
"Master is directing me back to home." (When receiving the RTH command)
"I'm in within 20 meters, and I can land now! I don't need to ascend." (The drone descends and lands without turning the nose)

TIPS:

The drone automatically lands when RTH is triggered within a 20 meter radius, BUT users can operate the control stick to avoid dangers!

PS: If the flight altitude is higher than the RTH altitude,the drone will just turn the direction of the nose and return to the HomePoint.
PPS: If the RTH altitude is set as 50 meters and the user pushes the throttle stick, the drone will return at the current flight altitude. It's easy to crash into something.
DO NOT operate the control stick when the drone is returning to the Home Point!
In the next section, we'll look at some examples of crashes and flyaways while using RTH.

Example 1:
"After pressing RTH button, the drone ascended and hit an obstacle."
Remember that the drone will ascend to the RTH altitude when RTH is triggered!

Example 2:
"When flying the drone on a mountain, I lost image transmission. When pressing the RTH button, the remote controller sounded, but I could not find my drone. So I operated the sticks, and the drone lost."
Don't operate the control sticks if you can't see your drone! Just wait patiently for it to return to you. Make sure you record a Home Point before flying.

Example 3:
"When pressing RTH button, the drone automatically descended into the water."
Remember, the drone automatically lands if RTH is triggered when the drone is within a 20 meters radius of the Home Point. Unlike in the previous case, use the control sticks to stop the drone from descending!
Let's stop here today.

Please remember to set the Home Point before using RTH and wait patiently during the return. DO NOT look for the drone anywhere else.
Also, please remember to set the RTH altitude.
Lastly, hope all of you have a great time flying!


(soure: http://forum.dji.com/thread-38269-1-1.html)