scholarly journals Research on Attitude Models and Antenna Phase Center Correction for Jason-3 Satellite Orbit Determination

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2408
Author(s):  
Mingming Liu ◽  
Yunbin Yuan ◽  
Jikun Ou ◽  
Yanju Chai
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Satellite Orbit ◽  
Event File ◽  
Phase Center ◽  
Special Cases ◽  
Antenna Phase ◽  
The Difference ◽  
Phase Center Variation ◽  
Antenna Phase Center

We focused on the researches of two models used for Jason-3 precise orbit determination (POD)—Jason-3 attitude modes and receiver phase center variation (PCV) model. A combined attitude mode for the Jason-3 satellite is designed based on experimental analysis used in some special cases, such as in the absence of quaternions or when inconvenient to use. We researched the linking of satellite attitude with antenna phase center. Specially, to verify the validity of the combined attitude, we analyzed the effects of different attitude modes on receiver phase center offset (PCO) estimation, PCO correction and POD. Meanwhile, the difference analysis of PCO correction based on attitude modes also contains the combined attitude modeling processes. The POD results showed that the orbital accuracies with the combined attitude are slightly more stable than those with attitude event file. By introducing receiver PCVs into POD, the mean residuals root-mean-square (RMS) is reduced by 1.9 mm and orbital 3D-RMS position difference is improved by 5.7 mm. The eight schemes were designed to integratedly verify the effectiveness of different attitude modes and receiver PCVs model. The results conclude that the accuracy using the combined attitude is higher than that of event file, which also prove the feasibility of the combined attitude in integrated POD and it can be as a revision of attitude event file. Using all mentioned attitude modes, the orbital accuracy by introducing PCVs can be improved by the millimeter level. The integrated effects of attitude modes and receiver PCVs on POD are almost consistent with the effects of a single variable. The optimal results of Jason-3 POD indicate that orbital mean radial RMS is close to 1 cm, and the 3D-RMS position difference is within 3 cm.

Impact of different attitude modes on Jason-3 precise orbit determination and antenna phase center modeling

2021 ◽  
Author(s):  
Cyril Kobel ◽  
Daniel Arnold ◽  
Adrian Jäggi
Keyword(s):  
Orbit Determination ◽  
Precise Orbit Determination ◽  
Global Navigation Satellite Systems ◽  
International Gnss Service ◽  
Error Sources ◽  
Phase Center ◽  
Precise Orbit ◽  
Yaw Attitude ◽  
Antenna Phase ◽  
Antenna Phase Center

<p>Global Navigation Satellite Systems such as the Global Positioning System (GPS) are a unique tool for deriving very precise orbits of Low Earth orbiting (LEO) satellites equipped with onboard GPS receivers. LEO precise orbit determination (POD) requires the proper modeling of antenna phase center variations (PCVs) for both the GPS transmitter and the LEO receiver antennas. While for the GPS antennas the nadir-dependent values from the official absolute antenna phase center model igs14.atx of the International GNSS Service (IGS), consistent with the underlying GPS orbit and clock products, are used, official PCV maps are usually not available for the LEO receiver antennas. If these variations are not considered, however, this may result in systematic errors in the derived LEO orbits. LEO PCV maps can be determined and exploited in different ways. One possibility is to use the PCV maps from ground calibrations provided by the manufacturer, which usually do not reflect, however, the influence of error sources which are additionally encountered in the actual spacecraft environment, e.g., near-field multipath. Alternatively, one can make use of GPS measurements and POD results to estimate the PCV map empirically, as it is done in this study.</p><p>In this study, the influence of different attitude modes on Jason-3 POD using GPS observations and PCV map estimation is investigated. As Jason-3 in an altimetry satellite, its main objective is to measure global sea-level rise. Therefore, it is of particular importance to precisely determine the radial component of the orbit and proper PCV modeling is of high importance. As Jason-3 is experiencing different attitude modes, yaw-steering and fixed-yaw attitude with either the positive or negative x-axis pointing in the direction of flight, PCV maps are expected to be better disentangled from other error sources. In this study, we are analyzing PCV maps determined from residual stacking using GPS data from the different attitude modes and from different orbit parametrizations. First results indicate that PCV maps estimated from time spans of different attitude modes differ and systematic orbit differences are occurring in a reduced-dynamic POD.</p>

Recent Advances in Galileo and BeiDou Precise Orbit Determination

2020 ◽  
Author(s):  
Florian Dilssner ◽  
Erik Schönemann ◽  
Volker Mayer ◽  
Tim Springer ◽  
Francisco Gonzalez ◽  
...  
Keyword(s):  
Orbit Determination ◽  
Rotation Axis ◽  
Laser System ◽  
Precise Orbit Determination ◽  
Recursive Least Squares ◽  
Phase Center ◽  
Precise Orbit ◽  
Antenna Phase ◽  
Antenna Phase Center ◽  
Better Than

<p>To produce Global Navigation Satellite System (GNSS) orbits and clocks with high accuracy and for all constellations, the ESA’s Navigation Support Office (NSO) continually strives to keep abreast and improve its precise orbit determination (POD) strategies. In this presentation, we report on NSO’s recent developments and progress in Galileo and BeiDou POD. We first discuss the approach of improving Galileo POD solutions through a prudent combination of radiometric and satellite laser ranging (SLR) measurements at the observation level. For this technique to be effective, SLR normal point (NP) data from the Galileo SUCCESS campaign are used. Launched by the European Laser Network (EUROLAS) in the middle of May 2019, this three-week tracking campaign provided over 1000 NPs for two selected Galileo spacecraft: GSAT0102 and GSAT0220. We show that the precision of the GSAT0102 and GSAT0220 orbits is more than 10 percent better than that produced by solutions without SLR data. In this performance evaluation, we also discuss the presence of station-specific SLR biases, taking advantage of near-simultaneous SLR tracking by two or three separate laser sites. Additionally, we demonstrate that the SLR full-rate data from a single kHz laser system can be used to determine the Galileo satellites’ yaw state during eclipse maneuvers. This approach takes advantage of the 1.0 m distance between a Galileo spacecraft’s laser retroreflector array (LRA) and rotation axis to estimate the yaw angle in a recursive least-squares algorithm epoch by epoch. The method may serve as an interesting alternative to reverse kinematic point positioning (RPP), particularly for LRA-equipped satellites without significant transmit antenna phase center offsets. Finally, we present the first centimeter-quality orbit solutions for BeiDou’s third-generation series of medium Earth orbit (MEO) spacecraft. We discuss the POD strategy underlying these orbits and evaluate its performance by way of several metrics including laser range residuals, day-to-day orbit overlaps, satellite clock residuals, as well as RPP estimates as measure for the attitude model accuracy. Challenges pertaining to the satellite antenna phase center and radiation force modeling are addressed. The results on the overlap and SLR residuals suggest that our BeiDou-3 MEO orbits are accurate to better than 5 cm in all three components. Therefore, the new BeiDou constellation is fully integrated into our operational multi-GNSS routine, bringing the total number of daily processed GNSS satellites to more than 110 (http://navigation-office.esa.int/products/gnss-products).</p>

scholarly journals SHORT STATIC GPS/GLONASS OBSERVATION PROCESSING IN THE CONTEXT OF ANTENNA PHASE CENTER VARIATION PROBLEM

2015 ◽  
Vol 21 (1) ◽  
pp. 213-230 ◽  
Author(s):  
Karol Dawidowicz ◽  
Rafal Kazmierczak ◽  
Krzysztof Swiatek
Keyword(s):  
Vertical Component ◽  
Phase Center ◽  
Positioning Systems ◽  
Height Determination ◽  
Antenna Phase ◽  
Measurement Session ◽  
Visible Effect ◽  
Phase Center Variation ◽  
Antenna Phase Center ◽  
Phase Center Variations

So far, three methods have been developed to determine GNSS antenna phase center variations (PCV). For this reason, and because of some problems in introducing absolute models, there are presently three models of PCV receiver antennas (relative, absolute converted and absolute) and two satellite antennas (standard and absolute). Additionally, when simultaneously processing observations from different positioning systems (e.g. GPS and GLONASS), we can expect a further complication resulting from the different structure of signals and differences in satellite constellations. This paper aims at studying the height differences in short static GPS/GLONASS observation processing when different calibration models are used. The analysis was done using 3 days of GNSS data, collected with three different receivers and antennas, divided by half hour observation sessions. The results show that switching between relative and absolute PCV models may have a visible effect on height determination, particularly in high accuracy applications. The problem is especially important when mixed GPS/GLONASS observations are processed. The update of receiver antenna calibrations model from relative to absolute in our study (using LEIAT504GG, JAV_GRANT-G3T and TPSHIPER_PLUS antennas) induces a jump (depending on the measurement session) in the vertical component within to 1.3 cm (GPS-only solutions) or within 1.9 cm (GPS/GLONASS solutions).

GNSS antenna phase center variation calibration for attitude determination on short baselines

Navigation ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 643-654 ◽  
Author(s):  
Daniel Willi ◽  
Michael Meindl ◽  
Hui Xu ◽  
Markus Rothacher
Keyword(s):  
Attitude Determination ◽  
Phase Center ◽  
Antenna Phase ◽  
Phase Center Variation ◽  
Antenna Phase Center ◽  
Short Baselines

scholarly journals Comparisons of CODE and CNES/CLS GPS satellite bias products and applications in Sentinel-3 satellite precise orbit determination

GPS Solutions ◽  
2021 ◽  
Vol 25 (4) ◽  
Author(s):  
Bingbing Duan ◽  
Urs Hugentobler
Keyword(s):  
Linear Combination ◽  
Orbit Determination ◽  
Fractional Part ◽  
Precise Orbit Determination ◽  
Satellite Orbit ◽  
Satellite Orbits ◽  
Satellite Clock ◽  
Analysis Center ◽  
Wide Lane ◽  
Total Difference

AbstractTo resolve undifferenced GNSS phase ambiguities, dedicated satellite products are needed, such as satellite orbits, clock offsets and biases. The International GNSS Service CNES/CLS analysis center provides satellite (HMW) Hatch-Melbourne-Wübbena bias and dedicated satellite clock products (including satellite phase bias), while the CODE analysis center provides satellite OSB (observable-specific-bias) and integer clock products. The CNES/CLS GPS satellite HMW bias products are determined by the Hatch-Melbourne-Wübbena (HMW) linear combination and aggregate both code (C1W, C2W) and phase (L1W, L2W) biases. By forming the HMW linear combination of CODE OSB corrections on the same signals, we compare CODE satellite HMW biases to those from CNES/CLS. The fractional part of GPS satellite HMW biases from both analysis centers are very close to each other, with a mean Root-Mean-Square (RMS) of differences of 0.01 wide-lane cycles. A direct comparison of satellite narrow-lane biases is not easily possible since satellite narrow-lane biases are correlated with satellite orbit and clock products, as well as with integer wide-lane ambiguities. Moreover, CNES/CLS provides no satellite narrow-lane biases but incorporates them into satellite clock offsets. Therefore, we compute differences of GPS satellite orbits, clock offsets, integer wide-lane ambiguities and narrow-lane biases (only for CODE products) between CODE and CNES/CLS products. The total difference of these terms for each satellite represents the difference of the narrow-lane bias by subtracting certain integer narrow-lane cycles. We call this total difference “narrow-lane” bias difference. We find that 3% of the narrow-lane biases from these two analysis centers during the experimental time period have differences larger than 0.05 narrow-lane cycles. In fact, this is mainly caused by one Block IIA satellite since satellite clock offsets of the IIA satellite cannot be well determined during eclipsing seasons. To show the application of both types of GPS products, we apply them for Sentinel-3 satellite orbit determination. The wide-lane fixing rates using both products are more than 98%, while the narrow-lane fixing rates are more than 95%. Ambiguity-fixed Sentinel-3 satellite orbits show clear improvement over float solutions. RMS of 6-h orbit overlaps improves by about a factor of two. Also, we observe similar improvements by comparing our Sentinel-3 orbit solutions to the external combined products. Standard deviation value of Satellite Laser Ranging residuals is reduced by more than 10% for Sentinel-3A and more than 15% for Sentinel-3B satellite by fixing ambiguities to integer values.

Experimental Determination of DRW Antenna Phase Center at mm-Wavelengths Using a Planar Scanner: Comparison of Different Methods

2011 ◽  
Vol 59 (8) ◽  
pp. 2806-2812 ◽  
Author(s):  
Pablo Padilla ◽  
Patrik Pousi ◽  
Aleksi Tamminen ◽  
Juha Mallat ◽  
Juha Ala-Laurinaho ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Phase Center ◽  
Antenna Phase ◽  
Antenna Phase Center
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