Block I and Block II

Block I and Block II refer to different versions of the GPS Satellite Block series. Block I, the original design launched in the 1970s and early 1980s, provided the first operational GPS signals. Block II, introduced later, is an improved version with enhanced accuracy, signal strength, and reliability. These upgrades included better atomic clocks and signal processing, ensuring more precise GPS navigation. The transition from Block I to Block II marked the progression toward a more robust and accurate satellite system, supporting military and civilian users worldwide.