Impact of Multi-GNSS Antenna-Receiver Calibrations in the Coordinate Domain

Abstract

<p>In order to obtain highly precise positions with Global Navigation Satellite Systems (GNSS), it is mandatory to take all error sources adequately into account. This includes phase center corrections (PCC), composed of a phase center offset (PCO) and corresponding azimuthal and elevation-dependent phase center variations (PCV). These corrections have to be applied to the observations since the pattern of the GNSS receiver antennas deviate from an ideal omnidirectional radiation pattern.<br>The Institut für Erdmessung (IfE) is one of the IGS accepted institutions for absolute antenna calibration. Recently, the operationally calibration procedure has been further developed to a post processing approach. Thus, PCC can also be estimated for all frequencies (including e.g. GPS L2C, L5) and systems like Galileo and Beidou. Additionally, the newly developed approach allows to assess the impact of using different receivers with different settings on an individual calibration. <br>Previous studies already have shown, that the geodetic receivers used during the absolute calibration of antennas have an impact on the estimated PCC. However, currently this impact is only analysed at the level of the respective patterns and not in the coordinate domain. Moreover, the results are always only valid for the respective antenna-receiver combination. Therefore, more samples of different combinations are required.<br>In this contribution, we study calibration results of several antenna-receiver combinations using a zero baseline configuration during the calibration process in order to assess the receiver’s impact due to different signal tracking modes. The resulting PCC are analysed on the pattern level regarding (i) the repeatability of individual calibrations and (ii) differences between different antenna-receiver combinations. Finally, the impact of the different PCC are validated in the coordinate domain by a well controlled short baseline and common clock set-up. Here, again a zero baseline configuration with the identical receivers used during the calibration process is performed. Consequently, the impact of the respective antenna-receiver combination with individually estimated PCC on the positioning is analysed.</p>

Early Results on GNSS Receiver Antenna Calibration System Development

“…To fulfill the requirements of high-accuracy positioning applications, the receiver antenna PCCs must be determined. In line with the IGS convention, and as depicted in Figure 1, PCC is divided into the phase center offset (PCO) vector and the azimuth-and elevation-dependent phase center variation (PCV) [4,6,[10][11][12]14]:…”

“…Today, absolute filed calibration is the state of the art when it comes to GNSS receiver antenna calibration. Only a few calibration systems utilizing a precise robot are operational or under development worldwide [5][6][7][8][9][10][11][12], and even fewer are accredited by the International GNSS Service (IGS) to provide antenna calibration results [13]. Since this topic is of high interest to the scientific antenna community, and a new calibration system is highly desirable, at the Laboratory for Measurements and Measuring Technique (LMMT) of the Faculty of Geodesy of the University of Zagreb in Croatia, a new antenna calibration system has been developed [14].…”

GNSS Receiver Antenna Absolute Field Calibration System Development: Testing and Preliminary Results

“…Recently, Geo++ GmbH upgraded its system for absolute multi-frequency and multi-GNSS calibrations [19]. In parallel to the operational calibration system, the Institute of Geodesy of the University of Hannover is developing its new experimental system [7,9,20,21]. In addition to the above-mentioned two, the Geo++ GmbH calibration system is additionally operational at Geoscience Australia in Canberra, Australia [22], and Senatsverwaltung für Stadtentwicklung Berlin (SenB), Germany [19].…”

“…Furthermore, with the development and modernization of GNSS [38] and the availability of new GNSS signals, the need for their calibration emerges. Today, the lack of consistent multi-frequency multi-GNSS antenna calibration values is a challenging issue [9,21]. Several research results show significant antenna calibration pattern differences between different institutions and calibration methods [39][40][41][42].…”

“…The constant parameter r, contained in Equation ( 4), is denoted as the datum parameter and is present due to the relative character of GNSS observations, i.e., because with GNSS, only one-way pseudo-ranges can be measured. This parameter does not affect the position estimates and is fully absorbed into the receiver clock error [9,12,39,47]. By analyzing Equation ( 4), it is evident that a set of PCC values can be transformed to any PCO vector and PCV set.…”