Galileo and GLONASS group delay variations

Beer, Susanne; Wanninger, Lambert; Heßelbarth, Anja

doi:10.1007/s10291-019-0939-7

Cited by 9 publications

(5 citation statements)

References 17 publications

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“…Based on these absolute receiver antenna GDV we are now able to estimate absolute multi-frequency GNSS satellite antenna GDV for GPS, GLONASS, Galileo, BeiDou, and QZSS. Since no such receiver antenna GDV corrections were available in earlier studies (Wanninger et al 2017;Beer et al 2020), the results for satellite antenna GDV differ from earlier estimations, especially at frequencies with large receiver antenna GDV.…”

Section: Introductioncontrasting

confidence: 83%

“…Our estimation of absolute multi-frequency and multi-GNSS satellite antenna GDV is based on terrestrial observations of globally distributed reference stations and the code-minuscarrier (CMC) linear combination, which is also known as the linear multipath combination. For detailed descriptions of estimating GDV with the CMC approach, please refer to Wanninger and Beer (2015), Wanninger et al (2017), andBeer et al (2020).…”

Section: Methodsmentioning

confidence: 99%

“…The CMC approach was also applied to observations of reference stations to estimate Galileo and GLONASS GDV (Beer et al 2020). Homogenous results for antennas of the same satellite type indicate mainly receiver antenna specific GDV.…”

Section: Previous Work On Gdvmentioning

confidence: 99%

“…Because of the daily orbit repeat cycle of GPS, a globally distributed set of reference stations was necessary for this system. For the other MEO constellations, it was important to use data of a whole orbit repeat cycle but there was no need for globally distributed stations (Beer et al 2020). In the case of the IGSO satellites, reference stations in the Asia-Pacific region were needed.…”

Section: Datamentioning

confidence: 99%

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

2021

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GNSS 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.

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Section: Introductioncontrasting

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Section: Previous Work On Gdvmentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

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

2021

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“…Wübbena et al (2008) estimated CPC with their robot in a real-time process in a Kalman filter based on undifferentiated observations. The group from TU Dresden determined satellite and receiver antenna GDV together in a network approach by using code-minus-carrier linear combinations (CMC, Wanninger et al (2017), Beer et al (2019)). In 2019, Geo++ published absolute GDV for a set of 36 antennas (Wübbena et al 2019); based on these values Beer et al (2021) were able to estimate absolute GDV for GNSSsatellite antennas with their CMC approach.…”

Section: Introductionmentioning

confidence: 99%

Estimation and Validation of Codephase Center Correction Using the Empirical Mode Decomposition

Breva

Kröger

Kersten

et al. 2022

International Association of Geodesy Symposia

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In high precision Global Navigation Satellite Systems (GNSS) applications, it is necessary to take phase center corrections (PCC) into account. Beside these corrections for carrier phase measurements, also corrections for the codephase are necessary, so called codephase center corrections (CPC). The CPC, also known as group delay variations, are antenna dependent delays of the received codephase, which are varying with azimuth and elevation of the incoming GNSS signal. A concept for estimating absolute CPC and PCC for multi GNSS signals has been established by the Institut für Erdmessung.In this paper, the standard calibration approach with a sampling rate of 1 Hz is briefly described, which works well for PCC estimation. The main challenge of this approach for estimating repeatable CPC patterns is the significantly higher noise to pattern ratio in the observations compared to PCC determination. Therefore, an alternative processing strategy is presented in this contribution. By increasing the sampling rate to 10 Hz, the empirical mode decomposition can be used to reduce the noise of the input observations by maintaining all pattern information. With this method, the calibration repeatability is improved by 46% to 60% for GPS and Galileo C1C signals for a geodetic antenna. Moreover, the estimated pattern is validated in the positioning domain with a single point positioning approach. By considering the estimated CPC the accuracy of the height component can be improved.

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

Breva

Kröger

Kersten

et al. 2023

International Association of Geodesy Symposia

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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.

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Galileo and GLONASS group delay variations

Cited by 9 publications

References 17 publications

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

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

Estimation and Validation of Codephase Center Correction Using the Empirical Mode Decomposition

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

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