Which of the following describes a characteristic of a multiplexing receiver in GPS?

• A. It is a hybrid receiver combining both code correlation tracking and code-less tracking.
• B. It uses only code correlators with continuous code tracking.
• C. It relies on carrier-phase tracking without code tracking.
• D. It cannot track multiple satellites simultaneously.

Answer: (A)

Multiplexing in GPS receivers means handling several satellites at once by sharing processing resources and often switching between tracking modes. In this sense, the described receiver is a hybrid that combines code correlation tracking with code-less (carrier-based) tracking. Code correlation tracking locks onto each satellite’s pseudorandom C/A code to obtain the pseudorange measurements that form the navigation solution. Code-less tracking, or carrier-based tracking without relying on the code, allows the receiver to maintain a stable carrier phase lock even when the code tracking is weak or unavailable, which helps preserve high-rate phase measurements and overall continuity. The multiplexing capability is what makes it practical to track multiple satellites simultaneously while employing these different tracking strategies as needed. This is why it’s the best description: it captures both the multi-satellite capability and the combination of tracking modes that a multiplexing receiver uses. The other options describe single-mode or non-satellite-tracking scenarios (or imply you can’t track multiple satellites), which do not fit the concept of a multiplexing, hybrid GPS receiver.