Context: Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 uses satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible. The area that can be serviced is from longitude 70°E to 140°E and from latitude 5°N to 55°N. A frequency of the system is 2491.75 MHz.

Question: What type of satellites does the American GPS system use?
Answer: medium Earth orbit satellites

Question: What type of satellites does the BeiDou-1 system use?
Answer: satellites in geostationary orbit

Question: What is the purpose of the BeiDou-1 system using stallites in geostationary orbit?
Answer: the system does not require a large constellation of satellites

Question: What service area is covered by the BeiDou-1 system?
Answer: from longitude 70°E to 140°E and from latitude 5°N to 55°N

Question: What is the frequency of the BeiDou-1 system?
Answer: 2491.75 MHz

Question: BeiDou-1, along with American GPS, use which type of satellites? 
Answer: Unanswerable

Question: BeiDou-1, along with Russian GLONASS, use which type of satellites? 
Answer: Unanswerable

Question: BeiDou-1, along with European Galileo systems, use which type of satellites? 
Answer: Unanswerable

Question: Which is a frequency of the vehicular system?
Answer: Unanswerable

Question: Although, BeiDou-1 uses medium Earth orbit satellites, American GPS systems use which kind?
Answer: Unanswerable