Every flown mission from the mission compendium for XW/TIE/XvT/BoP/XWA gains you one point. The one with most points at the end of the month wins an IS-BW and the title of "Gamma püilot of the month" for that month. The one with most points at the end of the year receives an IS-SW and the title "Gamma pilot of the year" for that year. Second at the end of the year receives an IS-BW.

IS-BW for best each month and the title "Gamma pilot of the month"
IS-SW for best at the end of the year and the title "Gamma pilot of the year"
IS-BW for second at the end of the year