Litchi Limitation

[pmshop]

While planning an extra long mission - 4 miles round trip (6.43km) I discovered a limitation.
You can only drop waypoints every 2km max (1.24mi)
And, if you are looking for a smooth transition between waypoints, use the curve setting to "fly through" the waypoint.

According to Litchi, It is not a beta issue - it is a DJI limitation.

 

[Brojon]

While planning an extra long mission - 4 miles round trip (6.43km) I discovered a limitation.
You can only drop waypoints every 2km max (1.24mi)
And, if you are looking for a smooth transition between waypoints, use the curve setting to "fly through" the waypoint.

According to Litchi, It is not a beta issue - it is a DJI limitation.

Actually you *don't* want to fly through a waypoint - you want the curve to be wide enough to miss it.
Every time you hit a waypoint it pauses. It is in fact a Dji SDK issue.
As far as the 2 km limitation - I don't think I've ever flown a mission with a segment that long. I guess it would be a drag to have it pause at that waypoint for no good reason.
However - better than no waypoint missions at all right?

 

[pmshop]

Actually you *don't* want to fly through a waypoint - you want the curve to be wide enough to miss it.
Every time you hit a waypoint it pauses. It is in fact a Dji SDK issue.
As far as the 2 km limitation - I don't think I've ever flown a mission with a segment that long. I guess it would be a drag to have it pause at that waypoint for no good reason.
However - better than no waypoint missions at all right?

You are correct sir!

 

[IanSR]

Silly ot question, but what happens with this software if the remote looses connection to the craft? Does it return to home or does it continue the mission?

 

[pmshop]

Silly ot question, but what happens with this software if the remote looses connection to the craft? Does it return to home or does it continue the mission?

Continues the mission.
Litchi loads the flight plan to some kind of available memory for execution.
Example: I lost contact after the 4th turn until 1:40

Low battery is the only RTH failsafe when flying a mission.
You have guidance how long the mission is when planning.
For a Spark, keep the mission under 12 minutes to be safe.

 

[RENOV8R]

only an educated guess, but I would assume that since the mission is entered into the app, not the RC, that it would continue on it's mission. Basically the same as Ardupilot Mission Planner. The problem would arise that you would not be able to alter the course of your planned mission if need be.

 

[Brojon]

Continues the mission.
Litchi loads the flight plan to some kind of available memory for execution.
Example: I lost contact after the 4th turn until 1:40

Low battery is the only RTH failsafe when flying a mission.
You have guidance how long the mission is when planning.
For a Spark, keep the mission under 12 minutes to be safe.

Litchi will only execute RTH at the end of mission if that's what you explicitly told it to do.
Otherwise it sits there dumb as a rock - well, a flying rock anyway.
So rule #1 when using Litchi is to set and end of mission action or prepare to walk or run to where it ended if you're out of range.

 

[Brojon]

Silly ot question, but what happens with this software if the remote looses connection to the craft? Does it return to home or does it continue the mission?

It will continue the mission. One of its strong points actually.
When the mission finishes it will execute whatever you specified as the end of mission action or just sit there hovering.
I usually set the end of mission back to where I started so I don't have to worry about remembering if I set it.

 

[pmshop]

It will continue the mission. One of its strong points actually.
When the mission finishes it will execute whatever you specified as the end of mission action or just sit there hovering.
I usually set the end of mission back to where I started so I don't have to worry about remembering if I set it.

It will RTH when it runs low on battery.
I tested that this morning.

 

[Brojon]

That's a drone failsafe and not a Litchi function. You can set the RTH value to something stupid that won't make it home.
As far as RTH goes, I was fascinated to see that it works slightly different with the Spark.
It's a good idea to familiarize yourself with the nuances..

 

[Tafische]

From what I can tell so far playing with Litchi, the Spark does not appear to know how much battery it needs to get home while on a mission (but still testing). It may very well initiate a RTH, but if you have gone too far out you probably will not make it back and it will failsafe land.

Also I would not solely rely on the time that Litchi says the mission will take. I am still experimenting, but I dont think they times are all that accurate on accent and decent. They also dont take into account a strong headwind.

I am doing no more than 8 minute missions until I get quite a few flights under my belt.

 

[Brojon]

From what I can tell so far playing with Litchi, the Spark does not appear to know how much battery it needs to get home while on a mission (but still testing). It may very well initiate a RTH, but if you have gone too far out you probably will not make it back and it will failsafe land.

Also I would not solely rely on the time that Litchi says the mission will take. I am still experimenting, but I dont think they times are all that accurate on accent and decent. They also dont take into account a strong headwind.

I am doing no more than 8 minute missions until I get quite a few flights under my belt.

Interesting. I have a standard test pattern mission I run to test flying time and RTH behavior. It'll be interesting to see if this is the case. I would assume the RTH is always triggered at the critical setpoint - admittedly I'm assuming the same setting exists as the Mavic and Phantom. On those drones Go 4 has a warning level and then a critical level. The warning is just that - an incessant beep to let you know that level was reached. Critical however triggers the action you have selected - land or fly home.
You *can* set it to a value that won't make it back. At some point - I think 5-7% - it will land and nothing you can do will stop it.

 

[pmshop]

From what I can tell so far playing with Litchi, the Spark does not appear to know how much battery it needs to get home while on a mission (but still testing). It may very well initiate a RTH, but if you have gone too far out you probably will not make it back and it will failsafe land.

Also I would not solely rely on the time that Litchi says the mission will take. I am still experimenting, but I dont think they times are all that accurate on accent and decent. They also dont take into account a strong headwind.

I am doing no more than 8 minute missions until I get quite a few flights under my belt.

It will not let you go out too far.
I saw the red failsafe bar grow as the Spark got further away.
I was sending it out on the 4km round trip mission with too low of battery to even reach 1km and it came back.

Litchi won't let you fail it seems.

 

[Tafische]

This is what I THINK is the RTH Algorithm

Manually Flying (Litchi and DJI) -
* Loss of Signal - Go home
* Low Battery - software RTH or push button activated. RTH point is calculated much more conservatively in DJI App and is based on distance and height from home point
* Very low battery - force land in place

Mission Flying (Litchi)
* Loss of Signal - Continue on Mission
* Low Battery with Signal - Will trigger RTH based on distance from controller
* Low Battery w/o signal - Still TBD. It does not appear Litchi/Spark has any type of failsafe that would force a RTH based on distance from home point.
* Very low battery - force land in place


Please feel free to correct / add to this list.

 

[pmshop]

This is what I THINK is the RTH Algorithm

Manually Flying (Litchi and DJI) -
* Loss of Signal - Go home
* Low Battery - software RTH or push button activated. RTH point is calculated much more conservatively in DJI App and is based on distance and height from home point
* Very low battery - force land in place

Mission Flying (Litchi)
* Loss of Signal - Continue on Mission
* Low Battery with Signal - Will trigger RTH based on distance from controller
* Low Battery w/o signal - Still TBD. It does not appear Litchi/Spark has any type of failsafe that would force a RTH based on distance from home point.
* Very low battery - force land in place


Please feel free to correct / add to this list.

You must have been typing while I was posting

Verified RTH kicks in if the battery failsafe is triggered during a mission

 

[Brojon]

This is what I THINK is the RTH Algorithm

Manually Flying (Litchi and DJI) -
* Loss of Signal - Go home
* Low Battery - software RTH or push button activated. RTH point is calculated much more conservatively in DJI App and is based on distance and height from home point
* Very low battery - force land in place

Mission Flying (Litchi)
* Loss of Signal - Continue on Mission
* Low Battery with Signal - Will trigger RTH based on distance from controller
* Low Battery w/o signal - Still TBD. It does not appear Litchi/Spark has any type of failsafe that would force a RTH based on distance from home point.
* Very low battery - force land in place


Please feel free to correct / add to this list.

Well, I know with both the Mavic and Phantom it works almost exactly like the Dji Go4 when on a mission and it hits low battery.
It even gives you the option to cancel RTH. There's no refusing critical battery landing.

 

[Bob Johnston]

Critical battery landing is determined by ac as just enough power to land the ac. On both my spark and P3 standard the RTH behaviors are the same. I wonder if RTH and critical landing are common to all the DJI aircraft?

 

[IanSR]

Wow thanks for the answers, a couple more, does the software change the ac into ce wifi mode, or does it just ignore that setting?

And can you side load the app onto a phone? My phone doesn't have google play on it, so even though I'd happily pay for the software, I'd need to side load it.

 

[Brojon]

You talking about Litchi or the Dji Go 4 Mod 2.0 app?
Litchi is only available thru Play. the modded dji app is able to be sideloaded

 

[IanSR]

Litchi, I was wondering if it's an account login type authentication or whether it's tied to the device when downloaded via play, I assume you don't have to login then at any stage?