The Effects of Antenna Setup Errors upon velocities of GNSS campaign measurement when gaps in data.

In this study, we investigate the effect of antenna setup errors upon on the accuracy of position velocities produced from GNSS campaign measurements when gaps in data. Our motivation in this study is to demonstrate the changes in station velocities in time series caused by certain antenna measurement errors, in addition to the reduced frequency of data obtained from campaign-style measurements, which are preferred due to maintenance costs, permanent stations being damaged or even lost while monitoring natural events. We used seven stations from the continuous GPS time series of JPL, NASA from a global network of the IGS. For each station, we generated 1460 data for four years synthetic GNSS campaign time serieswithout gaps and 48 data with one measurement campaign per month. Subsequently, by creating data gaps through monthly campaigns, velocity estimates were made from datasets consisting of 32, 24, 16, and 8 data respectively. The same datasets were augmented with Gaussian noise simulating ±1-3 mm of antenna setup error. Velocity estimates were also made from these augmented datasets. Rms values calculated from antenna error-free datasets ranged between 0.1~0.5 mm for North, 0.2~0.5 mm for East, and 0.5~1.3 mm for Up directions. Rms values also calculated from antenna error datasets ranged between 0.2~0.9 mm for North, 0.2~0.7 mm for East, and 0.5~1.1 mm for Up directions. All velocity estimates were subjected to student t tests. About 1% variation was found for all components, both with and without antenna setup errors. The effect of antenna setup errors on data gaps in campaign-style measurements was demonstrated.

Keywords: GPS time series; GPS campaigns; Velocity estimation; Gaps in data; Antenna Setup Errors.