Height Variation Depending on the Source of Antenna Phase Centre Corrections: LEIAR25.R3 Case Study

In this study, we compared two sets of antenna phase center corrections for groups of the same type of antenna mounted at the continuously operating global navigation satellite system (GNSS) reference stations. The first set involved type mean models provided by the International GNSS Service (release igs08), while the second set involved individual models developed by Geo++. Our goal was to check which set gave better results in the case of height estimation. The paper presents the differences between models and their impact on resulting height. Analyses showed that, in terms of the stability of the determined height, as well as its variability caused by increasing the facade mask, both models gave very similar results. Finally, we present a method for how to estimate the impact of differences in phase center corrections on height changes.

A PROPOSED SIMPLIFIED TECHNIQUE FOR CONFIRMING HIGH PRECISION GNSS ANTENNA OFFSETS

The purpose of this research was to independently investigate and determine confirmatory calibration procedures for GNSS antennas. This paper focuses on the aspect of simplified techniques for confirming high precision GNSS antenna offsets. In the other words, the aim is to verify GNSS antenna offset parameters ‐ results, which will be used to find the consequences on ground positions of orbital distortions caused by solar activity. It is well known that the computation of GNSS observations using high precision GNSS antennas requires knowledge of the relevant antenna phase centre offsets. These offsets are the distance in three dimensions from the antenna's physical centre to the point in space at which the antenna ‘measures’ position. The calibration processes used by manufacturers appear to vary, and, where receivers of different models are to be used together, it is essential that the calibration parameters used are all produced using the same methods and by the same authoritative sources. Meanwhile, with the growth in the use of high precision GNSS systems, the likelihood of antennas being accidentally mishandled is possibly higher than previously. Finally, it is noted that it has long been the practise for surveyors to check their instruments to ensure that they are properly calibrated. In the modern electronic age, however, it seems that this practise has been allowed to lapse as far as GNSS instrumentation is concerned. With the above in mind, it has been decided to attempt to create a simplified procedure for calibrating high precision GNSS antennas. The aim is that it will be possible for the average surveyor to check his antenna without great effort or trouble. The objective can also be described as finding a simplified field procedure to determine whether a specific antenna's offset parameters are within reasonable agreement with published figures. Santrauka Straipsnyje analizuojamas supaprastintas metodas, kuriuo galima aprobuoti aukšto tikslumo globalines navigacines palydovines sistemos (GNPS) antenos nukrypimus. Siekiama patinkrinti GNPS antenos nukrypimo parametrus ‐ rezultatus, kurie bus naudojami nustatant GNPS palydovo orbitos iškraipymu padarinius. Nagrinejama procedūra, kai siekiama nustatyti, ar konkrečios GNPS antenos kalibravimo parametrai yra pagristi, palyginti su publikuotais duomenimis. Analizuojama problema yra aktuali, kai GNPS matavimams naudojamos aukšto tikslumo GNPS antenos ir reikalingos žinios, susijusios su antenos fazes centro nukrypimais.