Context: The ranging signals are based on the CDMA principle and have complex structure typical of Galileo or modernized GPS. Similar to the other GNSS, there will be two levels of positioning service: open and restricted (military). The public service shall be available globally to general users. When all the currently planned GNSS systems are deployed, the users will benefit from the use of a total constellation of 75+ satellites, which will significantly improve all the aspects of positioning, especially availability of the signals in so-called urban canyons. The general designer of the COMPASS navigation system is Sun Jiadong, who is also the general designer of its predecessor, the original BeiDou navigation system.

Question: What are the ranging signals of the BeiDou system based on?
Answer: the CDMA principle

Question: What positioning levels will the BeiDou system offer?
Answer: open and restricted (military)

Question: Where will the public service for the BeiDou system be available?
Answer: globally to general users

Question: Who designed the COMPASS navigation system?
Answer: Sun Jiadong

Question: How many satellites will the COMPASS navigation system use?
Answer: 75+ satellites

Question: Which signals are based on the ABCD principle? 
Answer: Unanswerable

Question: The ranging signals have a simple structure and are based on which principle? 
Answer: Unanswerable

Question: The ranging signals, based on the Galileo principle, have what type of structure?
Answer: Unanswerable

Question: Who designed the COMPASS international trade system? 
Answer: Unanswerable

Question: Which system is the predecessor of the GNSS system?
Answer: Unanswerable