Verifying correct home point after takeoff

[lomposlapos]

How one ensure and verify that the M2P has the correct home point after takeoff?

IMU calibrated
compass calibrated
....

 

[Meta4]

How one ensure and verify that the M2P has the correct home point after takeoff?

Watch the bottom of your screen when you power up.
Before you get good GPS position information, next to D (for Distance from home) it will show N/A (Not Available)

When the drone gets a good GPS position fix, it will automatically record the home point and the D number will now show the distance from home.
It should be a very small number.

You can also check the map but it isn't really necessary

IMU calibrated
compass calibrated

If there's a question there, there's nothing to check.

 

[lomposlapos]

Thank you. So after power up, but before liftoff, I must see a stable small value (<1 m) in D in order to confirm a reliable home point. Correct?

Is this D based on GPS inside the aircraft and shows the distance from the airraft's position at the moment of the GPS turned on? (i.e., ideally should be 0.0 m until takeoff)

 

[Meta4]

Is this D based on GPS inside the aircraft and shows the distance from the airraft's position at the moment of the GPS turned on? (i.e., ideally should be 0.0 m until takeoff)

Because of the way GPS works, it will usually be slightly more than 0.0 metres.
That distance is how far the drone is from the recorded home position.

 

[msinger]

If you cached the maps in DJI GO or your mobile device is connected to the Internet, you can also look for the "H" symbol on the map to see where the home point is located.

 

[lomposlapos]

If you cached the maps in DJI GO or your mobile device is connected to the Internet, you can also look for the "H" symbol on the map to see where the home point is located.

I am using SC, every week a different country, no internet connection in the field or pre-downloaded maps. So I need, a SC/M2P self-contained, no internet solution.

 

[Meta4]

I am using SC, every week a different country, no internet connection in the field or pre-downloaded maps. So I need, a SC/M2P self-contained, no internet solution.

No internet is no problem.
The maps aren't terribly important and having no maps isn't a big deal.

 

[lomposlapos]

After liftoff, is there a reason to hover the aircraft above the liftoff position to ensure/verify accurate home point or not needed?

 

[old man mavic]

if you go up over the take off point to some 20ft or so and let it hover for a few seconds it helps it to land on the exact spot when you do a return to home,when a certain no of sats are recorded you will get the message the home point is recorded check it on the map dont take off before you have a good GPS lock

 

[FoxhallGH]

After liftoff, is there a reason to hover the aircraft above the liftoff position to ensure/verify accurate home point or not needed?

If you bear in mind that the Mavic uses a pair of downward pointing cameras to 'see' what's under it, as well as the GPS coordinates, then the more opportunity you can give the Mavic to get's its bearings when it lifts off, the better. Typically, I'll take my Mavic up slowly from the auto-take-off hover altitude to 10 metres before I do any further control inputs. I've found that pretty much guarantees a landing within a few cm of the take-off point.

 

[old man mavic]

i think that the mavic and mavic pro platinums take off feature where you have a tic box to enable precision RTH was and still is a good idea,it gives you choices on how you want it to do a RTH and if chosen then i can attest that it hits the landing mat every time within a inch or two of its take off point for some reason they did away with the tic box on the mavic2 and instead pilots have to remember to go up to 25 or so feet hover and then move off, omitting this part of the process will mean the mavic2 will land sometimes several feet from the take off point,as has been stated by many people on this forum and on you tube

 

[msinger]

After liftoff, is there a reason to hover the aircraft above the liftoff position to ensure/verify accurate home point or not needed?

There's no need to hover or take off slowly. If you want to use the Precision Landing feature, then make sure you ascend straight up for at least 23 feet. See more details here:

HOW TO: Use Precision Landing with the Mavic 2 Pro/Zoom

When the Mavic 2 Pro and Mavic 2 Zoom drones were released in August, the Precision Landing feature was not included. Many people who upgraded from other DJI drone models were upset that this feature was not carried over to the Mavic 2 and a long debate started over in this thread in the DJI […]

www.djidronenews.com

 

[RedBird2020]

When executing an auto take off, let the drone ascend to what ever height "IT Wants to go" and it will stop automatically. Let it sit there for about 5 seconds.

My Mavic Air would ascend to 16 feet then stop to capture Precision Landing data. My Mavic 2 Pro ascends to 4 feet then stops to capture Precision Landing data. There is a message that pops up telling you what height your drone will ascend to and stop. WHERE EVER it stops when using auto take off is the height YOUR drone needs to record Precision Landing data.

I've tested the 5 second rule (My Rule) and when I auto ascend to XX feet and then immediately fly off the drone seldom returns to the (near) exact landing pad location (usually within 10 feet though). BUT when I let auto take off and hover (at what ever height it wants to) and let it hover there for several seconds, the drone will (almost) always land back on my orange/blue landing pad from which it departed when I use the Return To Home button.

If you do the same 5 second hover in low light conditions (like flying to capture a sunset), the sensors have a hard time matching up with the precision landing data upon returning that it recorded at time of take off (because its getting darker quickly) and the drone will have to depend solely on GPS recoded at take off for a landing location. Sometime it will hit the landing pad, sometimes it will not. Your good for about 6 to 10 feet accuracy in that case. So, Yes it does record its Precision Data at auto take off if you give it time to do so.

Upon return to home, GPS gets the drone close to landing sight and then it switches into Precision Landing mode to match the current scenery of the ground with what it recorded on take off.

In the .txt files these messages appear:

-- APP_TIP_tip message issued: Aircraft is returning to the Home Point. Minimum RTH Altitude is196ft. You can reset the RTH Altitude in Remote Controller Settings after cancelling RTH.

-- APP_TIP_tip message issued: Aircraft close to Home Point. "go home" shifts to "landing"

-- APP_TIP_tip message issued: Precision Landing__Locating Landing Point


*** "Your results may vary" LOL, had to toss that in there....