5
Preflight Mission Planning
DROTAG
relies on APM messages to trigger the camera and add tags to it, so it is worth taking the time
to learn how to efficient mission planning. At Airborne Projects we do the planning of the mission and
waypoint upload through Mission Planner.
Although planning a mission in Mission Planner or others is outside the scope of this manual there are
some details that need to be taken into account. Specifically the
"Photo every (est)"
and the
"Trigger
Method"
.
Other parameters and tutorials on Mission Planner can be found on this link. We seriously advise our
customers to get comfortable with tutorials as this part of the flight is the only one which is not automated.
5.1
Time Between Pictures or "Photo every (est)"
With the Sony Alpha Series, a full resolution JPEG picture with the advised settings never exceeds the
10 MBytes size. As the
DROTAG
needs to download the picture to process it, the "
Photo every (est)
"
parameter
should not be less than 3 seconds
. If the time between triggers in your mission plan is less
than 3 seconds some pictures may be missed or triggered out of turn, producing undesirable results.
To achieve always the best results, play with your mission parameters in order to achieve more than 3
seconds between photographs.
There are many ways around the
"Photo every (est)"
parameter, each with their own drawbacks. Below,
you can find the available approaches in order of best to worse:
1.
Slightly Slower Flight -
Your mission will take longer to fly but all your pictures will be with the
desired Ground Resolution (pixel/cm) which is the normal requirement parameter when doing aerial
photography.
2.
Higher Altitude -
When flying higher you can sacrifice Ground Resolution to obtain pictures with
bigger area covered. With bigger area covered in each picture, the more time you have to take next
one. You may hit a hard limit on both the altitude as well as on the Ground Resolution requirements.
3.
Overlap or Sidelap reduction -
It may be possible, due to end use of the collected pictures to
reduce the sidelap or overlap of the pictures so that they are less frequent. This increases the time
between pictures.
3