The high-resolution sensors that UAS can carry offer incredible enhancement opportunities relative to the amount, resolution, persistence, and analytics applied to remotely collected data. Previously operated DOI UAS platforms and associated sensors have provided image resolution improvements of 1,200% over Landsat 8 satellite scenes and a 400% increase over manned aircraft collections. Several of these UAS compatible sensors are also interchangeable in the field, allowing for the collection of high-resolution natural color, thermal, hyperspectral, multispectral, LiDAR, RADAR, geomagnetic and other types of data over the same area at approximately the same time.
Sensor Specifications and Imagery Examples
Natural Color
Natural color sensors, also known as electro-optical (EO) or RGB, operate in the visible light range of the electromagnetic spectrum, i.e., the wavelengths that the human eye can detect. EO cameras are available in a wide range of light-weight inexpensive full-motion video (FMV) or single-lens reflex models easily mounted on UAS platforms. Combined with surveyed ground control points (GCPs), overlapping imagery from these cameras is processed using SfM photogrammetry software to produce high-resolution orthophotos, 3D point clouds, and digital elevation models.
Current Sensors: Phase One iXM-100, Ricoh GR II, Sony a6000, Sony a7R, Sony RX1R II
Thermal
Thermal infrared (IR) are heat sensors that detect emitted radiation within the IR part of the spectrum to measure temperature differences. Thermal sensors mounted on UAS can collect non-contact temperature measurements of surfaces in the form of raster images to generate absolute and relative temperature orthophotos. Absolute temperature orthophotos have a pixel value associated with a surface temperature. Relative temperature orthophotos display the neighboring temperatures (within the image) of different features using false color palettes such as white hot, black hot, etc.
Current Sensors: FLIR Vue Pro
Multispectral
Multispectral cameras collect information across the entire electromagnetic spectrum, using multiple bandwidths, usually split into less than 12 distinct regions of the spectrum. Most commercially available UAS compatible multispectral cameras can collect images in the visible and near-infrared (VNIR) wavelengths (400 – 1000 nm). Image data acquired in this range are commonly utilized for land surface classification and vegetation monitoring. One of the most popular uses for VNIR imagery is calculating a normalized difference vegetation index (NDVI).
Current Sensors: MicaSense Altum, MicaSense RedEdge 3, MicaSense RedEdge-MX, MicaSense RedEdge-MX Dual
LiDAR
LiDAR (Light Detection and Ranging) is an active sensor used to obtain highly accurate and precise three-dimensional (3D) measurements of surface locations in the form of point clouds, i.e., collections of points with associated locations in x,y,z space. LiDAR sensors mounted on a low-altitude UAS platform collect surface elevations for ground positions sampled at regularly spaced horizontal intervals to generate high-resolution point clouds. These point clouds provide critical information about the Earth's surface, such as light intensity/reflectivity, structural forest canopy metrics, structural heights, and bare-ground elevation.
Current Sensors: YellowScan Surveyor
Radar
Radar is an active sensor that operates with polarization at dual or quad-polarization with phase to measure an object's full polarization response. Radar systems operate in the radio wavelengths (on the order of 103 m), while LiDAR systems utilize light with shorter wavelengths in the visible, near-infrared, and ultraviolet wavelengths (10-7 to 10-9 m).
Current Sensors: QCam
Retired Sensors
Canon Powershot S100
Canon Powershot SX230
Canon Powershot SX260
GoPro Hero2
GoPro Hero3
GoPro Hero4
Sony A5100
Sony A5100 with Voigtlander lens
