Aerial Survey

Applications
Title	Aerial Survey
Author(s)	GMV.
Level	Medium
Year of Publication	2011

Aerial Survey is a form of collection of geographical information using airborne vehicles. The collection of information can be made using different technologies such as aerial photography, radar, laser or from remote sensing imagery using other bands of the electromagnetic spectrum, such as infrared, gamma, or ultraviolet. For the information collected to be useful this information needs to be georeferenced. The georeferencing of information is usually done using GNSS with similar techniques as the techniques used for dynamic land surveying.

Application Architecture

Aerial Surveying is normally done using maned aeroplanes were the sensors (cameras, radars, lasers, detectors, etc) and the GNSS receiver are setup and are calibrated for the adequate georeferencing of the collected data. Apart from maned aeroplanes, other aerial vehicles can be also used such as UAVs, ballons, helicopters.

Multiple sensors of different or similar types can be used in order to collect different types of information or to be able to build 3D computer models of the terrain (e.g. stereoscopic cameras).

The data collected can be used for different purposes such as:

• Sea surveys (sea level, temperature, undulation, etc)
• Land survey (cartography, topography, feature recognition, etc)
• Monitoring vegetation and ground cover
• Reconnaissance

Application Characterization

Laser profiling from helicopters, carrying special electromagnetic sensors, which allow thickness estimates to be made of individual ice floes, will examine ice properties. Alternatively, ice core drilling and subsequent laboratory analysis may be carried out.

Aircrafts with radar and laser altimeters can measure ice sheet profiles.

Application Examples

Two of the most used forms of Aerial Survey are:

• Aerial Laser Profiling - Aerial Laser Profiling uses short duration laser pulses that are emitted towards the ground, reflected and detected by a receiver in the airborne vehicle. The time between the emission of the pulse and the reception can be used to determined the distance traveled by the pulse.
• Aerial Photogrammetry - In aerial photogrammetry aerial photos are taken in order to produce 2D or 3D terrain models. Multiple cameras might need to be used to build 3D models.