- The current GPS constellation consists of 32 Block II/IIA/IIR/IIR-M satellites.
- GPS constellation and individual satellite status is updated every working day.
- Block I are referred to as the original concept validation satellites developed by Rockwell International and reflect various stages of system development.
- The first Block II satellite was launched in February 1989; the most recent Block IIR-M satellite was launched on March 15, 2008.
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