What is the role of cycle-slip detection in GNSS network processing?

• A. To identify and handle discontinuities in carrier-phase tracking that would bias solutions, often by reinitializing the phase or discarding affected data.
• B. To calibrate the receiver's clock bias automatically.
• C. To convert carrier-phase data to pseudorange data.
• D. To determine the absolute orientation of the network.

Answer: (A)

Cycle-slip detection in GNSS processing is about spotting breaks in carrier-phase measurements that would bias the solution. Carrier-phase data are extremely precise, but they can lose lock or experience sudden phase jumps, causing a jump by one or more full cycles. If these slips aren’t found, the estimated ambiguities become inconsistent, which can bias position estimates and other parameters. Detecting a cycle slip lets the system reinitialize the phase tracking or discard the affected data, preserving the integrity of the network solution.

This isn’t about automatically calibrating the receiver’s clock bias; clock bias is estimated from the observations rather than fixed by cycle-slip checks. It isn’t about converting carrier-phase data to pseudorange data, which involves different processing steps. And it doesn’t determine the absolute orientation of the network, which is a geometric property of station geometry rather than a carrier-phase continuity issue.