Precise point positioning (PPP) is a promising positioning technique that is based on observations from a single global positioning system (GPS) receiver together with precise satellite orbit and clock products. Traditionally, a dual-frequency receiver is used to remove the first-order ionospheric effect easily by the linear combination of dual-frequency pseudoranges and carrier phases. The position, receiver clock offset, float ambiguities, and the zenith wet tropospheric delay are the unknowns in the PPP functional model (Zumberge et al. 1997; Kouba and Heroux 2001).
PPP is a next-generation positioning technology because of its ease of practice, cost-effectiveness, and improved positioning accuracy (Gao and Shen 2002).