Context: In-mid 2015, China started the build-up of the third generation BeiDou system (BDS-3) in the global coverage constellation. The first BDS-3 satellite was launched 30 September 2015. As of March 2016, 4 BDS-3 in-orbit validation satellites have been launched.

Question: When did China begin constructing the third BeiDou system?
Answer: mid 2015

Question: What is the third BeiDou system called?
Answer: BDS-3

Question: When was the first BDS-3 satellite launched?
Answer: 30 September 2015

Question: How many BDS-3 satellites have been launched?
Answer: 4

Question: Which system did China start building in March of 2017?
Answer: Unanswerable

Question: Which satellite was first launched on September 27th, 2015?
Answer: Unanswerable

Question: As of which month during 2016 were there 17 BDS-3 satellites in orbit?
Answer: Unanswerable

Question: When did Africa begin constructing the third BeiDou system?
Answer: Unanswerable

Question: How many BDS-20 satellites have been launched?
Answer: Unanswerable