TY - CHAP

T1 - On the Impact of GNSS Receiver Settings on the Estimation of Codephase Center Corrections

AU - Breva, Yannick

AU - Kröger, Johannes

AU - Kersten, Tobias

AU - Schön, Steffen

N1 - Publisher Copyright: © The Author(s) 2023.

PY - 2024

Y1 - 2024

N2 - The role of codephase center corrections (CPC), also known as group delay variations (GDV), becomes more important nowadays, e.g. in navigation applications or ambiguity resolution. CPC are antenna dependent delays of the received codephase. They are varying with the angle of arrival of the signal at the GNSS antenna, i.e. with azimuth and elevation. CPC can be determined with a robot in the field with a similar approach as used for phase center corrections (PCC) for carrierphase measurements. The big challenge in the estimation of reliable CPC pattern is to deal with relatively noisy codephase observations compared to the correction magnitude. A better repeatability can be reached by reducing the overall codephase noise. One possibility to do this is to understand and improve the tracking loops of the receiver, especially the loop filters, within the calibration process. Due to highly dynamic stress caused by the fast robot motion, a perfect tracking of the GNSS signals is challenging. In this paper, a detailed look on the impact of different loop filter settings, like the noise bandwidth, the filter order or the use of an aided or unaided delay lock loop, on the time differenced single differences is done. To this end, an antenna calibration experiment was carried out, where, in addition to the hardware receivers, the IFEN Sx3 software receiver was used. The software receiver allows to change the settings in post-processing. The experiment shows, that the noise of the observations can be reduced by decreasing the noise bandwidth, but pattern information can be lost by using a bandwidth, which is too small. The trade-off between a small bandwidth and consequently less overall noise and the signal dynamics, caused by the fast robot motion, must be chosen carefully. At the end, an improvement in the pattern repeatability from 99.2 mm, using a hardware receiver, to 65.6 mm, using a software receiver with carefully chosen parameters, can be achieved.

AB - The role of codephase center corrections (CPC), also known as group delay variations (GDV), becomes more important nowadays, e.g. in navigation applications or ambiguity resolution. CPC are antenna dependent delays of the received codephase. They are varying with the angle of arrival of the signal at the GNSS antenna, i.e. with azimuth and elevation. CPC can be determined with a robot in the field with a similar approach as used for phase center corrections (PCC) for carrierphase measurements. The big challenge in the estimation of reliable CPC pattern is to deal with relatively noisy codephase observations compared to the correction magnitude. A better repeatability can be reached by reducing the overall codephase noise. One possibility to do this is to understand and improve the tracking loops of the receiver, especially the loop filters, within the calibration process. Due to highly dynamic stress caused by the fast robot motion, a perfect tracking of the GNSS signals is challenging. In this paper, a detailed look on the impact of different loop filter settings, like the noise bandwidth, the filter order or the use of an aided or unaided delay lock loop, on the time differenced single differences is done. To this end, an antenna calibration experiment was carried out, where, in addition to the hardware receivers, the IFEN Sx3 software receiver was used. The software receiver allows to change the settings in post-processing. The experiment shows, that the noise of the observations can be reduced by decreasing the noise bandwidth, but pattern information can be lost by using a bandwidth, which is too small. The trade-off between a small bandwidth and consequently less overall noise and the signal dynamics, caused by the fast robot motion, must be chosen carefully. At the end, an improvement in the pattern repeatability from 99.2 mm, using a hardware receiver, to 65.6 mm, using a software receiver with carefully chosen parameters, can be achieved.

KW - Absolute Antennenkalibrierung

KW - Codephasenzentrumskorrekturen

KW - Group Delay Variations

KW - Loop filter

KW - Absolute antenna calibration

KW - Code phase corrections

KW - Group delay variation

KW - Loop filter

KW - Codephase center correction

KW - Group delay variations

UR - http://www.scopus.com/inward/record.url?scp=85200666459&partnerID=8YFLogxK

U2 - 10.1007/1345_2023_206

DO - 10.1007/1345_2023_206

M3 - Contribution to book/anthology

SN - 9783031638541

T3 - International Association of Geodesy Symposia

SP - 101

EP - 108

BT - Gravity, Positioning and Reference Frames - Proceedings of the IAG Symposia - GGHS2022

A2 - Freymueller, Jeffrey T.

A2 - Sánchez, Laura

PB - Springer Nature

CY - Berlin

ER -