Which statement best describes the function of the channels inside a GPS receiver?

• A. The receiver must isolate simultaneous signals from several satellites using dedicated channels
• B. The receiver uses a single channel to track each satellite
• C. The receiver cannot track more than one satellite at a time
• D. The receiver relies on time-division multiplexing to separate signals

Answer: (A)

GPS receivers rely on several tracking channels that operate in parallel to pull in signals from multiple satellites at once. Each channel is a tracking loop that locks onto a specific satellite’s signal by correlating the incoming signal with that satellite’s unique spreading code and Doppler-shifted carrier. This parallel set of channels lets the receiver extract separate pseudorange measurements from several satellites simultaneously, which is essential for computing a position.

The signals from different satellites are distinguished by code division multiplexing using their own pseudorandom codes, not by dividing time into slots. That’s why dedicated channels are needed: they provide simultaneous, independent tracking for multiple satellites. If you only had a single channel, you wouldn’t be able to track several satellites at the same time, and the system wouldn’t have enough measurements for a reliable position fix.