WPNAV_RADIUS set to 0 causes Copter to Loiter xx times at Waypoint 1?

Ground Control Software Mission Planner
1

Hi All

I am flying a quadcopter with AC3.5.4 , Mission 1.3.52 .

I do an AUTO Mission with WPNAV_RADIUS set to zero .
I plan a mission with first Waypoint [LOITER_TIME] with delay [3 seconds] and the second Waypoint set to RTL.

Problem:
During Auto Mission , copter navigates to Waypoint # 1 and then loiters there for more than 60 seconds until i manually RTL it.
{ Copter should loiter there for 3 seconds and then Return to Launch } .
I have checked everything regarding this problem as i know , the only Parameter i change was i set WPNAV_RADIUS to Zero .
Is this the parameter that causes Auto Mission to stop at Waypoint # 1.

Kindly help !!!
If someone could explain why this is happening i would be very thankful.
( Copter would have crashed loitering there but thanks to the Telemetry connection that informs me ).

2

Why would you ask it to hit an exact point with perfect precision in all axes ? You are asking for sub millimetre precision.

3

I set this parameter accidentally.

I wanna confirm that setting WPNAV_RADIUS to zero causes Copter to halt at Waypoint.

4

So if it is true then next time i would be very careful about this parameter and even include this in my Pre-flight
checklist.

Also i would like to raise this issue (in Github Issues Forum ) to add it as a Pre Arm Check like :
Pre-Arm : Check WPNAV_Radius Value .

5

One Question:
"
I have found this line in Releases Notes : Copter 3.5-rc7 25-May-2017

e) sanity check WPNAV_RADIUS is non-zero. "

Although i had no warning from Mission Planner about it.

6

You basically asked it to hit the point within 0.0000000m in all axis. It’s not stuck there, it just won’t hit it that perfectly.

It would be a ton of code to foolproof all parameters in preflight.

Beware of Mission planner, there are plenty of less … messy alternatives.

7

Ok. I understand this.

8

So from now on , i am adding this Parameter [WPNAV_RADIUS == 0] in my Pre-flight Checklist.

I had almost crashed my Copter due to this mistake.

Thankyou very much @Andre-K.