 
 <prompt> Wetin, we fit assume, BD for "BDS" mean? Based on the question wey dey before, write one context wey contain the answer. E fit be 1 - 20 sentences. Context: <response>: The BeiDou Navigation Satellite System (BDS) na Chinese satellite navigation system wey get two separate satellite constellations - one wey dey do small test since 2000, and one wey dey build full-scale global navigation system. 