| Acronym/Jargon | Explanation |
|---|---|
| AGL | Above ground level (Altitude) |
ATL | Above take-off level (Altitude) |
| CAD | Computer-aided design [document] Here, generally used to refer to schematic drawings of the layout of a solar plant. |
| Delta-Tm (ΔTm) | The measured temperature gradient of an anomaly (peak temperature of the anomaly minus reference temperature from a neighbouring, normal panel). |
| Delta-Tn (ΔTn) | Temperature gradient normalized to a standard irradiance of 1000 W/m². |
| DJI | SZ Dà-Jiāng Innovations Co., Ltd., a Chinese company selling drones and cameras. |
| Ec | Corrected Irradiance. Irradiance, E, measures the strength of sunlight falling on the photovoltaic modules, as measured using a pyranometer on the drone. To calculate Ec, this reading is corrected using the date, time and module plane.. |
| FLIR | FLIR systems. ('Forward-looking infrared'). A USA company producing infrared sensors and cameras. |
| FLIR-DPR | FLIR Duo Pro R [camera]. A type of hybrid (IR + visual) camera used for aerial thermography. * See also, FLIR |
| FOV | Field of view. Of a camera – the field of view produced by a lens of given focal length. Usually measured in degrees subtended. |
| GAP Device | Geolocation, accelerometry and pyranometry device. A bespoke device developed by Essex University and Above Surveying to capture irradiance readings and other telemetry. |
| GNSS | Global navigation satellite system. The standard term for satellite navigation systems. The most widely used of these currently is GPS, which is owned by the US military. |
| GPS | Global positioning system. See GNSS |
| GSD | Ground-sampling distance. Of a camera mounted on a UAV – the distance on the ground represented by 1 pixel in the resulting digital image. |
| IR | Infrared. * See above also, LWIR |
| LWIR | Long-wavelength infrared. The 8–15 µm region of the infrared spectrum, used for thermal imaging. Requires specialist cameras with sensors sensitive to these wavelengths. |
| O&M | Operations and management [organisation]. |
| One row per pass | See Rows per pass. |
| PID | Potential-induced degradation. A cause if mid-life failure of photovoltaic (PV) modules due to the unwanted migration of electrical charge carriers from the external materials of the panel into the semiconductors making up the PV cells. PID must be confirmed by ground-based testing of a PV module, and cannot be diagnosed using thermography alone. * See also, SEHP. |
| Pseudocolour | Infrared images are natively single-channel (greyscale). Various colour-maps (e.g. "iron" palette) can be applied to these images to improve presentation and feature-detection by the human eye. |
| RAMS | Risk assessment and methods statement |
| RGB | Red-green-blue [image]. An image captured in the visual spectrum (of the human eye), rather than in the infrared (thermal) spectrum, which only special sensors/cameras can detect. |
| Rows per pass | The number of "rows per pass" is the number of rows of solar panel tables which we capture in a single camera frame. If tables are close-enough together, then we can capture "two rows per pass", but typically we capture "one row per pass", and therefore our drone flies along every row of the solar farm. |
| SEHP | String-end heating pattern. A stereotypical pattern of hot-spots located at the ends of strings of photovoltaic (PV) modules, which is suggestive (but not pathognomonic) of PID. SEHP is readily detected by drone-based thermography. * See also, PID. |
| TA | Technical advisor |
| Two rows per pass | See Rows per pass |
| UAV | Unmanned aerial vehicle - the technical term for a 'drone'. |