Flying to Defined Low Heights Manually

[janoots2]

Hey guys, need some ideas. I have something coming up where 360 degree pans are required at 15', 25', 35' & 45'.

I was thinking about using a distance laser pointing it at the craft and then using that distance as the hypotenuse depending on my standing distance away from the takeoff point. But that could be challenging to get a read...

I fly wookong w/ Futaba - are there any accurate telemetry based altimeters that might work?

Any other ideas other than eyeballing it?

 

[PeterLester]

DJI sells an iOSD that can provide a data overlay onto your FPV screen.....From that program you can set an altitude alarm level.
Flying your MR in GPS mode will also help lock your MR into a fixed 3D position including altitude (to a significant degree)
However the altitude accuracy might not be as accurate as you prefer. A position marker on the ground may also help to improve accuracy.
With either tool above, an assistant can pace out an accurate distance of 50 feet from that marker so that you will have all the data necessary to do the height calculations using trig.

To further improve on altitude accuracy you might want to take advantage of one of the old model rocketry strategies for determining rocket altitude, i.e., trigonometry.
Estes Model rocketry sells a simple tool c/w instructions for doing that although it tends to be reactive versus proactive unless you plan ahead.
Another tool that will do the same c/w MR image and time recording is the following:
https://itunes.apple.com/ca/app/theodolite/id339393884?mt=8

 

[nickedw]

Well I built one of these to solve the same problem-

http://www.youtube.com/watch?v=QLOLlXz3Sss&feature=share&list=UUWxjDcSEBTgLc_xCn4PZiRQ&index=7

Since perfecting the electronics, I machined an aluminium load bearing and carbon fibre side frames, as it was for stills I didn't use a gimbal.

 

[Benjamin Kenobi]

Hey guys, need some ideas. I have something coming up where 360 degree pans are required at 15', 25', 35' & 45'.

I was thinking about using a distance laser pointing it at the craft and then using that distance as the hypotenuse depending on my standing distance away from the takeoff point. But that could be challenging to get a read...

I fly wookong w/ Futaba - are there any accurate telemetry based altimeters that might work?

Any other ideas other than eyeballing it?

I've done a few jobs like this. The iOSD is sufficient. Waypoints is apparently more accurate so I've heard.

 

[nickedw]

I've done a few jobs like this. The iOSD is sufficient. Waypoints is apparently more accurate so I've heard.

I tried using waypoints originally and it simply doesn't work. The aircraft moves off station as it turns, as well as crazy, seemingly random changes of rotation direction.
so to get from 60 to 90 degrees it doesn't necessarily move +30, it may well move -330.

Hence building something.

 

[kloner]

sounds like the rig is overloaded or not prepped as well as it can be... the flight controller can only do what it can with the equipment it is controlling. that tells me a manual method will be even more challenging. Imagine you in a ferrari, now imagine you in the same ferrari with a flat tire,,,, like that. most likely prop balance or a motor bearing issue but could include gains, insufficient thrust to weight, could be a zillion things but off what all you mentioned that'd be a good place to start

 

[nickedw]

sounds like the rig is overloaded or not prepped as well as it can be... the flight controller can only do what it can with the equipment it is controlling. that tells me a manual method will be even more challenging. Imagine you in a ferrari, now imagine you in the same ferrari with a flat tire,,,, like that. most likely prop balance or a motor bearing issue but could include gains, insufficient thrust to weight, could be a zillion things but off what all you mentioned that'd be a good place to start

I think you misunderstood me there. If you put say, six different bearings in, each +30 degrees for the same waypoint with Wookong or Naza, you will not get 6 smooth, clockwise rotations with a common centre point. Try it yourself. I have done a lot of testing of this with F550s and S800-evos, both properly trimmed, with optimum gain settings perfectly locked and stable in both normal and conventional waypoint flight.

IMHO the software treats each rotation as a new waypoint (it is) and performs re-calculation of position each time that results in deviation around the centre point.

Why it doesn't take the shortest angular route between rotations, is I suspect for the same reason.

 

[kloner]

i see what you mean, yea it's not much for a gimbal operator,,,,

 

[gtranquilla]

The Parrot "drone" has vertical sensing that enables precise height control. But I think it is sonar and needs a solid and flat surface below to work properly.
New V2V vehicle control includes a radar sensor that enables the following vehicle to automatically brake and maintain fairly accurate between vehicle distances.
The problem with conventional altitude control by means of altimeter/barometric sensor is that the barometric sensor accuracy is not very good and is affected by frequent air pressure variation including prop wash etc.

Hey guys, need some ideas. I have something coming up where 360 degree pans are required at 15', 25', 35' & 45'.

I was thinking about using a distance laser pointing it at the craft and then using that distance as the hypotenuse depending on my standing distance away from the takeoff point. But that could be challenging to get a read...

I fly wookong w/ Futaba - are there any accurate telemetry based altimeters that might work?

Any other ideas other than eyeballing it?

 

[janoots2]

I've been messing around and testing Theodolite and it seems surprisingly very accurate. I plan on measuring the distance from my 'straight up' take off point to where my assistant will be standing and have him snap the A & B points to confirm the heights. Thanks for the help everyone!!

 

[gtranquilla]

The simple way to use it is to stick with a 45 deg elevation angle and walk away from the hovering MR until the MR aligns with the 45 degree angle. The the pace distance = the altitude.

I've been messing around and testing Theodolite and it seems surprisingly very accurate. I plan on measuring the distance from my 'straight up' take off point to where my assistant will be standing and have him snap the A & B points to confirm the heights. Thanks for the help everyone!!

 

[janoots2]

I think this is the feature I'm going to try. It seems pretty accurate from my testing so far:

Height from A-B Elevation Angles
Aim at the bottom of the object to be measured and tap the A button, then aim at the top of the object and tap B. Theodolite will ask you to input the horizontal distance to the object, then it will calculate the object's approximate height based on the change in elevation angle between A and B. This is useful when you can easily make or estimate horizontal measurements but not vertical ones. You do not need to be on level ground for this measurement. Note that you do not need to specify units for this measurement -- the computed height will be in the same units as the input distance.

http://hunter.pairsite.com/mobile/theodolite/help/index4.html#ab