A Lesson on Observation Posts (OP)
During the GWOT we started slanting known definitions, mostly out of misunderstandings and no time to correct them. Or, everyone knew the terms were overly-generalized, but no one cared to correct the issue. A good example of this is the Observation Post (OP). In GWOT, we established many OPs along main supply routes, on roof tops in the cities; sometimes a patrol would turn into an overnight OP. Sometimes you will see training during which an individual goes and just sits in a position for a few hours, and will call it an OP.
Most veterans understand the extremely generalized usage of the term; however, this may mislead the average citizen, who does not understand what an OP actual is, and what it is utilized for. As it turns out, Observation Posts serve very specific tasks and purposes. FM 3-21.8 Infantry Rifle & Platoon (the updated FM 7-8) 3-93. An observation post provides the primary security in the defense. Observation posts provide early warning of impending enemy contact by reporting direction, distance, and size. It detects the enemy early and sends accurate reports to the platoon. The platoon leader establishes observation posts along the most likely enemy avenues of approach into the position or into the area of operation. Leaders ensure that observation posts (mounted or dismounted) have communication with the platoon. 3-94. Early detection reduces the risk of the enemy overrunning the observation post. Observation post may be equipped with a Javelin command launch unit; class 1 unmanned aircraft system; seismic, acoustic, or frequency detecting sensors to increase its ability to detect the enemy. They may receive infrared trip flares, infrared parachute flares, infrared M203 or M320 rounds, and even infrared mortar round support to illuminate the enemy. The platoon leader weighs the advantages and disadvantages of using infrared illumination when the enemy is known to have night vision devices that detect infrared light.
Although infrared and thermal equipment within the platoon enables the platoon to see the observation post at a greater distance, the observation post should not be positioned outside the range of the platoon’s small-arms weapons. 3-95. To further reduce the risk of fratricide, observation posts use GPS to navigate to the exit and entry point in the platoon’s position. The platoon leader ensures he submits an observation post location to the company team commander to ensure a no fire area is established around each observation post position.
As you can see, an OP typically is associated with the Patrol Base of a Squad or Platoon. A unit cannot defend their Patrol Base without an OP - on the other end, an OP cannot be supported at all unless it is connected to a Patrol Base. One last note: although the Marines use the term "LP/OP," to include Listening Posts, the Army does not. The Army shifted to just using "OP" because, the listening part is what is referred to as an "implied task." Basically, if you are observing, you are also listening. Unlike the rest of the Army, the Infantry tries to reduce redundancies!
Patrol Bases and OPs are just 10% of what we cover in the online academies and on-site SUT courses: https://www.gruntproof.us/p/training.html
Carry on
