Which statement best describes the primary advantage of precise point positioning (PPP) in GNSS processing?

• A. It enables real-time positioning using only local base stations.
• B. It relies on a dense network of reference stations to constrain the solution.
• C. It provides centimeter- to millimeter-level accuracy without a nearby reference station network.
• D. It reduces the need for dual-frequency observations.

Answer: (C)

Precise point positioning provides high-precision GNSS positioning without needing a nearby reference station network. It does this by using globally available precise satellite orbit and clock corrections, plus advanced models for ionospheric and tropospheric effects. With those global corrections and enough observation data, a single receiver can achieve centimeter- to millimeter-level accuracy anywhere, without relying on a dense local network of base stations.

While dual-frequency observations help improve accuracy and speed up convergence by better handling ionospheric delay and enabling precise ambiguity resolution, the standout advantage of PPP is its network-free capability. The other scenarios depend on nearby reference stations or networks to constrain the solution, which is not required for PPP.