observer-target line (OT line)

forward observer (FO), forward observation officer; (artillery) observer / spotter

factor OT/BT (observer-target/battery-target factor)

observer-target / battery-target factor (factor OT/BT)

coefficient of the line component of the observer-target factor

observer-target line

target-observer-gun

target-observer-gun method

Target, Trigger, Location, Observer, Delivery system, Attack guidance, and Communications (TTLODAC)

target scattering crossover / target scattering cross-section / electronic target profile

deployment line; line of deployment (LD); line of departure

electoral observer

forward observer team

liaison observer

military observer (MILOB)

military observer mission

observer

observer mission

United Nations Aouzou Strip Observer Group (UNASOG)

United Nations Disengagement Observer Force (UNDOF)

United Nations Iran-Iraq Military Observer Group (UNIIMOG)

United Nations Military Observer Group in India and Pakistan (UNMOGIP)

United Nations military observer mission

United Nations Observer Group in Central America (ONUCA)

United Nations Observer Mission in Angola (MONUA)

United Nations Observer Mission in Bougainville (UNOMB)

United Nations Observer Mission in El Salvador (UNOSAL / фр. ONUSAL)

United Nations Observer Mission in Georgia (UNOMIG)

United Nations Observer Mission in Liberia (UNOMIL)

United Nations Observer Mission in Sierra Leone (UNOMSIL)

United Nations Observer Mission in South Africa (UNOMSA)

United Nations Observer Mission to Verify the Referendum in Eritrea (UNOVER)

United Nations Observer Mission Uganda-Rwanda (UNOMUR)