This surface-to-air defense system is very advanced.
Tips
usage
地对空 is a military adjective always used attributively before nouns: 地对空导弹 (SAM, surface-to-air missile), 地对空防御 (SAM defense system). Counterparts in the family: 空对空 (air-to-air), 空对地 (air-to-ground), 地对地 (surface-to-surface).
memory
地 'ground' + 对 'toward/against' + 空 'air/sky' = 'ground-against-sky'. The 对 here means 'directed at', exactly like English 'to' in 'surface-to-air'. Once you learn the four-way grid (地/空 × 地/空), the whole family of terms unlocks at once.
