I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5 degrees."?
A:
What performs the same functions as Compass-M1 in the global navigation satellite system?