Search the entire archive like a dossier index.

Program 621B Early GPS Navigation Satellite Program

Program 621B mattered because it gave satellite navigation a military architecture before GPS had a name that would last. What the Air Force wanted was not simply another way to find position at sea or in occasional updates. It wanted continuous three-dimensional navigation for fast-moving aircraft, missiles, and precision weapons. In that form, 621B became more than an obscure research line. It became one of the decisive early black programs in the history of military positioning, because it supplied core ideas later absorbed into NAVSTAR: full-time satellite coverage, ranging signals built around pseudorandom noise, and a system-level view linking satellites, control, and receivers into one precision network.