Remote sensing of the earth (RS) is a type of geospatial technology that collects samples of emitted and reflected electromagnetic (EM) radiation from terrestrial, atmospheric and aquatic ecosystems to detect and monitor the physical characteristics of an area without physical contact. Most commonly, this data collection method typically involves aerial (at this stage exclusively UAVs) and satellite sensors, which are categorized as passive or active sensors (detectors). Ground-based sensors (instruments) are used locally and to enhance the quality of satellite and airborne data.

In recent years, ground-based sensors have been included in the field of remote sensing, which, in conjunction with space and aviation-based sensors, allows for obtaining a new level of detail for the investigated area or object.

Passive sensors respond to external stimuli by collecting radiation that is reflected or emitted by objects or the surrounding environment. The most common source of radiation measured by passive remote sensing is reflected sunlight. Popular examples of passive remote sensors include charge-coupled devices (CCD), digital images and video cameras, radiometers, hyperspectral, and infrared sensors.

Active sensors, on the other hand, use internal stimuli to collect data by emitting energy to scan objects and areas, after which the sensor measures the energy reflected from the target.

For example, RADAR and LiDAR sensors are typical active remote sensing instruments that measure the time delay between emission and return to establish the location, direction, and speed of an object. The collected remote sensing data is then processed and analyzed using remote sensing equipment and computer software (most advanced solutions offer quasi-real-time analytical products), which are available in various applications, primarily in Geographic Information Systems (GIS).