Binary offset carrier modulation

Binary offset carrier modulation (BOC modulation) was developed by John Betz in order to allow interoperability of satellite navigation systems. It is currently used in the US GPS system, Indian IRNSS system and in Galileo and is a square sub-carrier modulation, where a signal is multiplied by a rectangular sub-carrier of frequency f sc {\displaystyle f_{\text{sc}}} equal to or greater than the chip rate.

Source: Wikipedia — Binary offset carrier modulation (CC BY-SA 4.0)