Reconnaissance – this legal term applies in the area of Military Law. Reconnaissance details a preliminary investigation about the forces of the enemy, situated on a particular territory – subject of the survey. Usually, the investigation examines the structure of enemy forces, their power, mobility, etc. In addition, parts of the survey may include population, the infrastructure of help to the army force movement, rate of military supplies and others. Sometimes investigations are secret and only for the needs of the government in relation to prospective military actions. Modern armies use airplanes and drones to perform visual observation as part of the surveyance mission.
Synonyms are “exploration” and also “surveillance”.