GIS595/MEA792: UAV/lidar Data Analytics

Objectives

Describe phases of flight planning
Understand safety procedures and checklists
Understand the role of Ground Control Points and its distirbution and accuracy
Utilize flight planning software

UAS Photogrammetric process

Throughout the whole process, it is important to remember

What is the aim or the project? and
What will be the data used for?

Flight planning
- a multistep process

Throughout the whole process, it is important to remember

What is the aim or the project? and
What will be the data used for?

Project definition

defining the scope of the project
choosing UAS and sensor
assesing the cost, labor and time consumption
collecting information about terrain

Project definition

defining the area and resolution based on

UAS and sensor capabilies
size of mapping area
terrain constraints
project requirements

Project definition

evaluating the legal constrains, obtaining permissions
defining the coordinate system

dependent on the desired coordinate system of the final data
consistent with the coordinate system of GCP survey

Flight planning

mission area assesment
planning geometric parameters
choosing flight planning and flight logging platform
preliminary weather assesment (climate, season, forecasts)
creating a flight plan (software specific)

Placing Ground Control Points (GCPs)

A minimum number of 5 GCPs is recommended.
5 to 10 GCPs are usually enough, even for large projects.
In cases that the topography of the area is complex, use more GCPs

The GCPs should be distributed evenly in the area
Do not place the GCPs exactly at the edges of the area

Placing Ground Control Points (GCPs)

Before measuring the GCPs coordinates, the following items must be defined:

GCP coordinate system
GCP accuracy
Topographic equipment (total station or hand held GPS?)

GCPs Accuracy

Factors for defining GCP acuracy:

Accuracy needed for the final results
Ground Sampling Distance* of the images:

GCP target size: 5-10 x
GCP accuracy: at least 0.1 GSD

* distance between two consecutive pixel centers measured on the ground

Ground Sampling Distance

Distance between two consecutive pixel centers measured on the ground:

bigger GSD = lower spatial resolution

GSD depends on

flight altitude
camera focal length
camera resolution (pixel size)

Site evaluation and checklists

terrain check – high obstacles in the take-off, mission, landing and alternative landing locations
ask the locals about possible air traffic or ground activities
weather check

temperature effects battery life
most of the UAS can’t operate in rain.

use checklists, don't rely on your memory!
sample checklists: paper (for Phantom) and RMUS app

Site evaluation and checklists

Preflight inspection is required under Part 107.49;
the Remote Pilot in Comand (RPIC) is required to develop a preflight inspection checklist if the manufacture has not developed one.

NCDOT UAS Operational Procedures Guide

The checklist is usually integrated into the UAS flight software or can be obtained from the UAS vendor
In case that is not available, a standard Flight Checklist should be made and followed by the flight crew

Flight control

The UAS RPIC should launch, operate, and recover from preset locations so that the aircraft will fly according to the mission plan.
After the UAS is launched, the flight crew should have a clear view of the aircraft at all times, called Visual Line of Sight (VLOS). Observation locations should be selected for the maximum line of sight throughout the planned flight operations area (Part 107.31).

Flight control

To ensure the flight is going according to the flight plan, the RP, PMC and VO (if used) must be able to maintain effective communication with each other at all times (Part 107.33).
Upon any failure during the flight or any loss of visual contact with the UAS, the RPIC should command the aircraft back to the recovery location or utilize the built-in fail-safe features to recover the aircraft