The Ground Observer Corps was a series of Civil Defense

Civil defense

Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...

 programs in the United States to protect against air attack. First begun in World War II by the Army Air Forces

United States Army Air Forces

The United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....

, the 1.5 million civilian observers at 14,000 coastal observation posts used naked eye and binocular searches to find invading German and Japanese aircraft. The program ended in 1944.

In early 1950, the Continental Air Command

Continental Air Command

Continental Air Command was a Major Command of the United States Air Force responsible primarily for administering the Air National Guard and Air Force Reserve.-Lineage:...

 formed a new 8,000 post civilian Ground Observer Corps to supplement what would become the NORAD system. Over 200,000 volunteers participated in nationwide drills, telephoning dozens of coordination centers which in turn relayed information to the Air Defense Command (ADC) ground control interception centers.

By 1952 the program was expanded with a new organizational plan named Operation Skywatch with over three-quarters of a million volunteers taking shifts at over 16 thousand posts and 75 relay centers.

By the late 1950s, a major semi-automatic aircraft warning and detection system had been developed, Semi Automatic Ground Environment

Semi Automatic Ground Environment

The Semi-Automatic Ground Environment was an automated control system for tracking and intercepting enemy bomber aircraft used by NORAD from the late 1950s into the 1980s...

(SAGE), and was in the early stages of installation. Due to the dramatic technological improvements provided by this new system, the Air Force canceled the Ground Observer Corps program in 1959.

Sources

• Morgan, Mark Rings of Supersonic Steel: Air Defenses of the United States Army 1950-1974 HID Press 2002 [ISBN 0-615-12012-1]

• Schaffel, Kenneth The Emerging Shield (48 MB): The Air Force and the Evolution of Continental Air Defense, 1945-1960 USAF 1991 [ISBN 0-912799-60-9]