A modified carrier-to-code leveling method for retrieving ionospheric observables and detecting short-term temporal variability of receiver differential code biases

Sensing the ionosphere with the global positioning system involves two sequential tasks, namely the ionospheric observable retrieval and the ionospheric parameter estimation. A prominent source of error has long been identified as short-term variability in receiver differential code bias (rDCB). We modify the carrier-to-code leveling (CCL), a...

Joint estimation of vertical total electron content (VTEC) and satellite differential code biases (SDCBs) using low-cost receivers

Vertical total electron content (VTEC) parameters estimated using global navigation satellite system (GNSS) data are of great interest for ionosphere sensing. Satellite differential code biases (SDCBs) account for one source of error which, if left uncorrected, can deteriorate performance of positioning, timing and other applications. The...

Single-Frequency L5 PPP-RTK with GPS, IRNSS, QZSS and Galileo

The concept of PPP-RTK is to achieve integer ambiguity resolution (IAR) at a single GNSS user by providing network-derived satellite phase biases (SPBs) in addition to the standard precise point positioning (PPP) corrections. These corrections enable recovering integerness of user ambiguities, thereby recovering the full capability of the...

GNSS integer ambiguity estimation and evaluation: LAMBDA and Ps-LAMBDA

Successful integer carrier-phase ambiguity resolution is crucial for high precision GNSS applications. It includes both integer estimation and evaluation. For integer estimation, the LAMBDA method has been applied in a wide variety of GNSS applications. The method’s popularity stems from its numerical efficien-cy and statistical optimality....

GNSS ambiguity resolution: Which subset to fix?

A key issue with GNSS carrier phase ambiguity resolution is that often the full set of ambiguities cannot be fixed fast and reliably. A possible strategy is then to resolve only a subset of ambiguities, one for which the probability of correct fixing, the so-called success rate, is sufficiently close to 1. However, a proper subset selection...