HHQ-9 — Naval version.[19] HQ-9A — Upgraded version, first tested in 1999 and service entry in 2001.[19] Chinese sources claim that the HQ-9 family of systems employ much newer computing technology than imported Russian S-300PMU/PMU1/PMU2 systems, because HQ-9 is developed more than a decade later, thus allowing it to incorporate advancement in microelectronics. Due to the superior computing capability for signal processing, data processing and guidance support, this missile can have an optional semi-active radar homing (SARH) mode, because more info can be processed on board the missile itself.