Fixed-Wing vs Multi-Rotor UAS Platforms for Survey Operations

How to choose the platform you need

There are two main types of Unmanned Aerial Systems (UAS): fixed-wing and multi-rotor. There are benefits to each platform, and choosing a platform depends on several factors.

Fixed-Wing vs. Multi-Rotor

Fixed-wing UAS are well suited for collecting geospatial information over large areas as they typically fly at higher speeds and have greater endurance. They come as gasoline powered or battery operated - some are even hybrids. Unlike a rotor platform, they require a landing strip for takeoff and landing operations. 

Because fixed-wing aircraft are capable of flying at higher altitudes, they are ideal geospatial data capturing tools for medium scale mapping activities. For larger scale mapping, the fixed-wing platforms typically need to operate Beyond Visual Line of Sight (BVLOS) from the observer, an operation that currently comes with many restrictions. BVLOS technology is viewed by many as a means to replace mapping from manned aircraft.  This could be happening more and more in the near future.

Fixed-wing platforms are well suited for mapping linear assets such as pipelines, powerlines, and other corridor-type structures. Small fixed-wing platforms are susceptible to atmospheric conditions such as winds and tend to cause these aircrafts to bounce around during flight. This adversely affects the mapping activity and the ultimate accuracy of the results. For example, data from fixed-wing platforms on a windy day will result in reduced and irregular side lap and end lap of the sensor data collected. One way to mitigate this shortfall is to integrate a stabilization mount, so the sensor data is not affected by the turbulence experienced by the aircraft. The problem in doing so is that many of these small UAS today have a limited payload volume which prohibits adding a gimballed mount into the equation.

Multi-rotor aircraft, on the other hand, are more stable platforms tailored to performing small area geospatial surveys. They move at slower speeds and have the ability to hover in confined spaces, making them ideal for close-up inspections of bridges, communications towers, and for applications such as facade scanning of buildings. Multi-rotor aircraft typically have shorter flight times compared to fixed-wing aircraft since they are almost always battery operated.

The Application Matters

The mapping application dictates the type of platform that is required to carry out the job. There is no single type of UAS that fits all geospatial applications. For small area collects that require a high spatial and temporal accuracy, multi-rotor aircraft may be the solution, while for linear assets such as powerline mapping, fixed-wing aircraft might be better suited. Even within the spectrum of corridor mapping, the choice of platform type depends on the geospatial information being extracted from the map products. For example, if the insulator discs of high voltage powerlines need to be inspected, a multi-rotor aircraft might be better suited since it flies slowly and can get up close to the asset. On the other hand, if the right of way or unwanted vegetation growth needs to be mapped along a corridor, a fixed-wing might be better suited.

The UAS market is gaining momentum, and many professional mapping solutions are coming to market. More and more UAS platform manufacturers and system integrators are offering Directly Georeferenced turnkey mapping solutions equipped with sensor stabilization mounts, which are resulting in highly efficient, cost-effective, high accuracy, and aesthetically pleasing map products.