Context: The original idea of a Chinese satellite navigation system was conceived by Chen Fangyun and his colleagues in the 1980s. According to the China National Space Administration, the development of the system would be carried out in three steps:

Question: Who first came up with the idea for a Chinese satellite navigation system?
Answer: Chen Fangyun and his colleagues

Question: When did Chen Fangyun come up with the idea for a satellite navigation system?
Answer: in the 1980s

Question: The China National Space Administration said the satellite navigation system would be developed in how many steps?
Answer: three

Question: Who first came up with the idea for a Japanese satellite navigation system?
Answer: Unanswerable

Question: When did Chen Fangyun come up with the idea for an ocean navigation system?
Answer: Unanswerable

Question: The American National Space Administration said the satellite navigation system would be developed in how many steps?
Answer: Unanswerable

Question: What idea did Chen Fangyun come up with in 1924?
Answer: Unanswerable

Question: Who said the system would be developed in four total steps?
Answer: Unanswerable