scholarly journals Impact of flex power on GPS Block IIF differential code biases

GPS Solutions ◽  
2020 ◽  
Vol 24 (4) ◽  
Author(s):  
Özge Gizem Esenbuğa ◽  
André Hauschild
Keyword(s):  
Density Ratio ◽  
Bias Estimation ◽  
International Gnss Service ◽  
Transmit Power ◽  
Differential Code Bias ◽  
Regional Area ◽  
Code Bias ◽  
Block Iif ◽  
German Aerospace ◽  
Gps Block Iif

Abstract GPS Block IIF satellites are able to redistribute the transmit power between the signal components. This ability is called flex power, and it has been developed as a remedy against jamming. Since it is operationally not possible to increase the transmit power for all signal components simultaneously, a redistribution between them is necessary under certain operational situations. Flex power has been active on Block IIF satellites since January 2017 over a specific regional area and has an impact on differential code bias estimation as well as the signal-to-noise density ratio. A network of the International GNSS Service stations containing only Septentrio PolaRx5 and PolaRx5TR receivers between August 1 and November 21, 2019 has been used for differential code bias estimation using GPS L1 C/A, L1 P(Y), L2 P(Y), and L2C signals with and without consideration of the flex power in the estimation process for Block IIF satellites. The estimation results are compared with the German Aerospace Center as well as the Chinese Academy of Sciences DCB products to validate the results.

scholarly journals Characterization of GNSS Signals Tracked by the iGMAS Network Considering Recent BDS-3 Satellites

2018 ◽  
Vol 10 (11) ◽  
pp. 1736 ◽  
Author(s):  
Xin Xie ◽  
Rongxin Fang ◽  
Tao Geng ◽  
Guangxing Wang ◽  
Qile Zhao ◽  
...  
Keyword(s):  
Density Ratio ◽  
Assessment System ◽  
Triple Frequency ◽  
Signal Characteristics ◽  
Open Service ◽  
Code Bias ◽  
Block Iif ◽  
Navigation Signals ◽  
Gps Block Iif

The international GNSS monitoring and assessment system (iGMAS) tracking network has been established by China to track multi-GNSS satellites. A key feature of iGMAS stations is the capability to fully track new navigation signals from the recently deployed BDS-3 satellites. In addition to the B1I and B3I signals inherited from BDS-2 satellites, the BDS-3 satellites are capable of transmitting new open service signals, including B1C at 1575.42 MHz, B2a at 1176.45 MHz, and B2b at 1207.14 MHz. In this contribution, we present a comprehensive analysis and characterization of GNSS signals tracked by different receivers and antennas equipped in the iGMAS network, especially as they relate to BDS-3 signals. Signal characteristics are analyzed in terms of the carrier-to-noise density ratio for the different signals as measured by the receiver, as well as pseudo-range noise and multipath. Special attention is given to discussion of the satellite-induced code bias, which has been identified to exist in the code observations of BDS-2, and the inter-frequency clock bias (IFCB), which has been observed in the triple-frequency carrier phase combinations of GPS Block IIF and BDS-2 satellites. The results indicate that the satellite-induced code bias is negligible for all signals of BDS-3 satellites, while small IFCB variations with peak amplitudes of about 1 cm can be recognized in BDS-3 triple-carrier combinations.

Influence of the GLONASS inter-frequency bias on differential code bias estimation and ionospheric modeling

GPS Solutions ◽  
2017 ◽  
Vol 21 (3) ◽  
pp. 1355-1367 ◽  
Author(s):  
Xiaohong Zhang ◽  
Weiliang Xie ◽  
Xiaodong Ren ◽  
Xingxing Li ◽  
Keke Zhang ◽  
...  
Keyword(s):  
Bias Estimation ◽  
Differential Code Bias ◽  
Ionospheric Modeling ◽  
Code Bias

scholarly journals Investigation and Validation of the Time-Varying Characteristic for the GPS Differential Code Bias

2019 ◽  
Vol 11 (4) ◽  
pp. 428 ◽  
Author(s):  
Haojun Li ◽  
Jingxin Xiao ◽  
Weidong Zhu
Keyword(s):  
Single Point ◽  
Time Varying ◽  
International Gnss Service ◽  
Data Set ◽  
Differential Code Bias ◽  
Triple Frequency ◽  
Code Bias ◽  
Constant Part ◽  
The Difference ◽  
Better Than

The time-varying characteristic of the bias in the GPS code observation is investigated using triple-frequency observations. The method for estimating the combined code bias is presented and the twelve-month (1 January–31 December 2016) triple-frequency GPS data set from 114 International GNSS Service (IGS) stations is processed to analyze the characteristic of the combined code bias. The results show that the main periods of the combined code bias are 12, 8, 6, 4, 4.8 and 2.67 h. The time-varying characteristic of the combined code bias, which is the combination of differential code bias (DCB) (P1–P5) and DCB (P1–P2), shows that the real satellite DCBs are also time-varying. The difference between the two sets of the computed constant parts of the combined code bias, with the IGS DCB products of DCB (P1–P2) and DCB (P1–P2) and the mean of the estimated 24-h combined code bias series, further show that the combined code bias cannot be replaced by the DCB (P1–P2) and DCB (P1–P5) products. The time-varying part of inter-frequency clock bias (IFCB) can be estimated by the phase and code observations and the phase based IFCB is the combinations of the triple-frequency satellite uncalibrated phase delays (UPDs) and the code-based IFCB is the function of the DCBs. The performances of the computed the IFCB with different methods in single point positioning indicate that the accuracy for the constant part of the combined code bias is reduced, when the IGS DCB products are used to compute. These performances also show that the time-varying part of IFCB estimated with phase observation is better than that of code observation. The predicted results show that 98% of the predicted constant part of the combined code bias can be corrected and the attenuation of the predicted accuracy is much less evident. However, the accuracy of the predicted time-varying part decreases significantly with the predicted time.

scholarly journals BDS-3 differential code bias estimation with undifferenced uncombined model based on triple-frequency observation

2020 ◽  
Vol 94 (4) ◽  
Author(s):  
Shengfeng Gu ◽  
YinTong Wang ◽  
Qile Zhao ◽  
Fu Zheng ◽  
Xiaopeng Gong
Keyword(s):  
Bias Estimation ◽  
Differential Code Bias ◽  
Model Based ◽  
Triple Frequency ◽  
Code Bias ◽  
Frequency Observation

scholarly journals MGR-DCB: A Precise Model for Multi-Constellation GNSS Receiver Differential Code Bias

2015 ◽  
Vol 69 (4) ◽  
pp. 698-708 ◽  
Author(s):  
Mohamed Abdelazeem ◽  
Rahmi N. Çelik ◽  
Ahmed El-Rabbany
Keyword(s):  
Total Electron Content ◽  
Satellite System ◽  
Mean Difference ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
International Gnss Service ◽  
Total Electron ◽  
Differential Code Bias ◽  
Gnss Receiver ◽  
Code Bias

In this study, we develop a Multi-constellation Global Navigation Satellite System (GNSS) Receiver Differential Code Bias (MGR-DCB) model. The model estimates the receiver DCBs for the Global Positioning System (GPS), BeiDou and Galileo signals from the ionosphere-corrected geometry-free linear combinations of the code observations. In order to account for the ionospheric delay, a Regional Ionospheric Model (RIM) over Europe is developed. GPS observations from 60 International GNSS Servoce (IGS) and EUREF reference stations are processed in the Bernese-5·2 Precise Point Positioning (PPP) module to estimate the Vertical Total Electron Content (VTEC). The RIM has spatial and temporal resolutions of 1° × 1° and 15 minutes, respectively. The receiver DCBs for three stations from the International GNSS Service Multi-GNSS Experiment (IGS-MGEX) are estimated for three different days. The estimated DCBs are compared with the MGEX published values. The results show agreement with the MGEX values with mean difference and Root Mean Square Error (RMSE) values less than 1 ns. In addition, the combined GPS, BeiDou and Galileo VTEC values are evaluated and compared with the IGS Global Ionospheric Maps (IGS-GIM) counterparts. The results show agreement with the GIM values with mean difference and RMSE values less than 1 Total Electron Content Unit (TECU).

scholarly journals GPS and BeiDou Differential Code Bias Estimation Using Fengyun-3C Satellite Onboard GNSS Observations

2017 ◽  
Vol 9 (12) ◽  
pp. 1239 ◽  
Author(s):  
Wenwen Li ◽  
Min Li ◽  
Chuang Shi ◽  
Rongxin Fang ◽  
Qile Zhao ◽  
...  
Keyword(s):  
Bias Estimation ◽  
Differential Code Bias ◽  
Code Bias ◽  
Gnss Observations

Differential Code Bias Estimation using Multi-GNSS Observations and Global Ionosphere Maps

Navigation ◽  
2014 ◽  
Vol 61 (3) ◽  
pp. 191-201 ◽  
Author(s):  
O. Montenbruck ◽  
A. Hauschild ◽  
P. Steigenberger
Keyword(s):  
Bias Estimation ◽  
Differential Code Bias ◽  
Code Bias ◽  
Gnss Observations
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