Abstract
Precise ionospheric information, as like precise satellite orbits, clocks, and code/phase biases, is a critical factor for achieving fast integer ambiguity resolution in precise point positioning (PPP-AR). This study develops an ionosphere-weighted (IW) undifferenced and uncombined PPP real-time kinematic (PPP-RTK) network model using code and phase observations. We introduce between-station single-differenced ionospheric delay pseudo-observations to take advantage of the similar characteristics of ionospheric delays between two receivers tracking the same satellite. The estimable ionospheric parameters are commonly affected by the differential code bias referring to a particular receiver assigned as pivot, which facilitates the ionospheric interpolation at the user side. Then, the kinematic positioning performance of the IW PPP-RTK user model is analyzed and compared with those of PPP-AR without ionospheric corrections, RTK, and IW-RTK models during low and high solar activity days. The results show that for the PPP-RTK model, the positioning errors converge to thresholds of 2 cm for the horizontal components and 5 cm for the vertical component within 20 epochs, and the positioning errors become stable after an initialization of 20 epochs with root-mean-squared (RMS) values of approximately 0.47, 0.58 and 1.66 cm for the east, north and up components, respectively, which are superior to those of the other three models. Owing to the high ionospheric disturbance influence, the RMS values of the east and up components increase by approximately double and the mean time-to-first-fix increases by 61.5% for the PPP-RTK case.
Highlights
Precise point positioning (PPP) proposed by Malys and Jensen (1990) and Zumberge et al (1997) has advantages such as a high level of flexibility without the limitation of dense networks, supporting unidirectional or broadcast communication and requiring a low bandwidth with statespace representative corrections
Low and high solar activity conditions are considered in our experiment to analyze the influence of ionospheric disturbance, as the PPP realtime kinematic (PPP-RTK) network the user models are constrained by extra ionospheric delays
The regional ionospheric total electron contents (TECs) estimated by the IW undifferenced and uncombined (UDUC) PPP-RTK network model during high and low solar activity days are presented and analyzed
Summary
Precise point positioning (PPP) proposed by Malys and Jensen (1990) and Zumberge et al (1997) has advantages such as a high level of flexibility without the limitation of dense networks, supporting unidirectional or broadcast communication and requiring a low bandwidth with statespace representative corrections. Over the past few years, several popular PPP-RTK methods, such as the integer recovery clock model (Laurichesse et al 2009), the decoupled satellite clock model (Collins et al 2008), the uncalibrated phase delay model (Ge et al 2008), and the undifferenced and uncombined (UDUC) model (Teunissen et al 2010) have been proposed. Compared with the former three ionosphere-free PPP-RTK methods, the UDUC PPP-RTK network model simultaneously estimates the ionospheric delays, which are the key for fast integer AR and are convenient for multi-frequency applications. Low and high solar activity conditions are considered in our experiment to analyze the influence of ionospheric disturbance, as the PPP-RTK network the user models are constrained by extra ionospheric delays
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
