scholarly journals Temporal Stability of GPS Transmitter Group Delay Variations

Sensors ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 1744 ◽  
Author(s):  
Susanne Beer ◽  
Lambert Wanninger
Keyword(s):  
Group Delay ◽  
Temporal Stability ◽  
Delay Variations

scholarly journals Very compact UWB antenna with group delay improvement

2015 ◽  
Vol 12 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Esmaeel Tahanian ◽  
Hamidreza Hasani
Keyword(s):  
Time Domain ◽  
Return Loss ◽  
Group Delay ◽  
Frequency Characteristics ◽  
Back Side ◽  
Antenna Gain ◽  
Uwb Antenna ◽  
Delay Variations ◽  
The Time Domain

In this paper, very compact (12mm?17mm) and simple UWB antenna is proposed. The achieved bandwidth of the presented antenna is from 3.05 GHz to 12.5 GHz and in the most of the bandwidth, the return loss is less than -20dB. In addition to frequency characteristics, time characteristics such as group delay variations for three different antenna positions, namely, front to front, back to back and side by side using CST MW studio are simulated and discussed. To improve the group delay variations, by changing the radius of the circle on the back side of the antenna, the antenna gain in different frequencies will be tuned, therefore, the time domain characteristics of the proposed antenna are greatly improved.

scholarly journals Group delay variations of GPS transmitting and receiving antennas

2017 ◽  
Vol 91 (9) ◽  
pp. 1099-1116 ◽  
Author(s):  
Lambert Wanninger ◽  
Hael Sumaya ◽  
Susanne Beer
Keyword(s):  
Group Delay ◽  
Delay Variations

scholarly journals Estimation of absolute GNSS satellite antenna group delay variations based on those of absolute receiver antenna group delays

GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Susanne Beer ◽  
Lambert Wanninger ◽  
Anja Heßelbarth
Keyword(s):  
Group Delay ◽  
Observation Data ◽  
Satellite Antenna ◽  
Phase Measurements ◽  
Gps Satellites ◽  
Antenna Phase ◽  
Antenna Phase Center ◽  
Delay Variations ◽  
Phase Center Variations ◽  
Code Pseudorange

AbstractGNSS satellite and receiving antennas exhibit group delay variations (GDV), which affect code pseudorange measurements. Like antenna phase center variations, which affect phase measurements, they are frequency-dependent and vary with the direction of the transmitted and received signal. GNSS code observations contain the combined contributions of satellite and receiver antennas. If absolute GDV are available for the receiver antennas, absolute satellite GDV can be determined. In 2019, an extensive set of absolute receiver antenna GDV was published and, thus, it became feasible to estimate absolute satellite antenna GDV based on terrestrial observations. We used the absolute GDV of four selected receiver antenna types and observation data of globally distributed reference stations that employ these antenna types to determine absolute GDV for the GPS, GLONASS, Galileo, BeiDou, and QZSS satellite antennas. Besides BeiDou-2 satellites whose GDV are known to reach up to 1.5 m peak-to-peak, the GPS satellites show the largest GDV at frequencies L1 and L5 with up to 0.3 and 0.4 m peak-to-peak, respectively. They also show the largest satellite-to-satellite variations within a constellation. The GDV of GLONASS-M satellites reach up to 25 cm at frequency G1; Galileo satellites exhibit the largest GDV at frequency E6 with up to 20 cm; BeiDou-3 satellites show the largest GDV of around 15 cm at frequencies B1-2 and B3. Frequencies L2 of GPS IIIA, E1 of Galileo FOC, and B2a/B2b of BeiDou-3 satellites are the least affected. Their variations are below 10 cm.

scholarly journals Nadir-Dependent GNSS Code Biases and Their Effect on 2D and 3D Ionosphere Modeling

2020 ◽  
Vol 12 (6) ◽  
pp. 995
Author(s):  
Martin Håkansson
Keyword(s):  
Total Electron Content ◽  
Group Delay ◽  
Three Dimensional ◽  
Satellite System ◽  
Integer Ambiguity ◽  
Electron Content ◽  
Two Dimensional ◽  
Total Electron ◽  
Ionosphere Modeling ◽  
Delay Variations

Recent publications have shown that group delay variations are present in the code observables of the BeiDou system, as well as to a lesser degree in the code observables of the global positioning system (GPS). These variations could potentially affect precise point positioning, integer ambiguity resolution by the Hatch–Melbourne–Wübbena linear combination, and total electron content estimation for ionosphere modeling from global navigation satellite system (GNSS) observations. The latter is an important characteristic of the ionosphere and a prerequisite in some applications of precise positioning. By analyzing the residuals from total electron content estimation, the existence of group delay variations was confirmed by a method independent of the methods previously used. It also provides knowledge of the effects of group delay variations on ionosphere modeling. These biases were confirmed both for two-dimensional ionosphere modeling by the thin shell model, as well as for three-dimensional ionosphere modeling using tomographic inversion. BeiDou group delay variations were prominent and consistent in the residuals for both the two-dimensional and three-dimensional case of ionosphere modeling, while GPS group delay variations were smaller and could not be confirmed due to the accuracy limitations of the ionospheric models. Group delay variations were, to a larger extent, absorbed by the ionospheric model when three-dimensional ionospheric tomography was performed in comparison with two-dimensional modeling.

Galileo and GLONASS group delay variations

GPS Solutions ◽  
2019 ◽  
Vol 24 (1) ◽  
Author(s):  
Susanne Beer ◽  
Lambert Wanninger ◽  
Anja Heßelbarth
Keyword(s):  
Group Delay ◽  
Delay Variations
Sign in / Sign up

Export Citation Format

Share Document