Citation X (C750)
Flight Crew Air Transport Pilot (ATP)
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Took Evasive Action
Environment - Non Weather Related; Procedure
At approximately 25 NM from DAWNA and descending through FL180; we experienced moderate wake turbulence from a preceding G-IV. The airplane recovered initially; however the second blast of disturbed air knocked the autopilot off with some pretty good upsets. I decided to maneuver the aircraft upwind (south of course) with a momentary level off; as the winds were out of that direction and should have helped the situation. I instructed my First Officer to notify ATC immediately but the frequency was pretty tied up. We hit a third round of wake turbulence after now paralleling the course 3/4 dot left; approximately 1.5 miles. Finally getting in touch with ATC and explaining our situation followed by a return to the KAYOH FIVE Arrival and instructing ATC of the need to remain above the glide path of the G-IV; we continued on the arrival and approach for a normal landing.Looking back; the only thing I would have done differently is hit the ID button to flash the ATC scope; possibly alerting the Controller that we needed to break in on the conversation. Maybe even squawking 7700 if we weren't able to reach ATC or get back on course in a timely manner. I didn't execute my emergency authority because I wasn't even a full dot off course and still was able to get back on course and make the altitude and speed restrictions.
CE-750 Captain reported encountering wake turbulence descending through FL180 in trail of a G-IV on arrival into SNA.