scholarly journals Multiplexing modulation design optimization and quality evaluation of BDS-3 PPP service signal

2022 ◽  
Vol 3 (1) ◽  
Author(s):  
Cheng Liu ◽  
Zheng Yao ◽  
Dun Wang ◽  
Weiguang Gao ◽  
Tianxiong Liu ◽  
...  
Keyword(s):  
Average Length ◽  
Large Diameter ◽  
Satellite System ◽  
Transmission Efficiency ◽  
Actual State ◽  
Signal Design ◽  
Binary Offset Carrier ◽  
Modulation Technique ◽  
Constant Envelope ◽  
S Curve

AbstractThe Precise Point Positioning (PPP) service of BeiDou-3 Navigation Satellite System (BDS-3) is implemented on its Geostationary Earth Orbit (GEO) satellites. However, its signal design is limited by the actual power of satellite and other conditions. Furthermore, the design needs to fully consider the compatibility of different service phases. Starting from the actual state of the BDS-3 GEO satellite, this paper studies the multiplexing modulation of the BDS PPP service signal that is based on the Asymmetric Constant Envelope Binary Offset Carrier (ACE-BOC) technique and proposes several feasible schemes for this signal. Comparison and optimization of these techniques are made from the aspects of transmission efficiency, multiplexing efficiency, and service forward compatibility. Based on the Type-III ACE-BOC multiplexing modulation technique, phase rotation and intermodulation reconstruction techniques are proposed to suppress the intermodulation interference issue. Finally, a signal based on improved ACE-BOC multiplexing is designed. The quality of the proposed signal was continuously monitored and tested using large-diameter antennas. The evaluation results show that the power spectrum deviation of the signal is 0.228 dB, the correlation loss is 0.110 dB, the S-curve slope deviation is 1.558% on average, the average length difference between the positive/negative chip and the ideal chip is only 0.0006 ns, and the coherence between the carrier and the pseudo code is 0.082°. All quality indicators are satisfactory, indicating that the proposed signal multiplexing modulation technique is an ideal solution that meets all the requirements of the design constraints, and can achieve efficient information broadcasting and forward compatibility of the BDS PPP service.

A Unified Dual-frequency Constant Envelope Multiplexing Design Framework for Modernised GNSS Signals

2018 ◽  
Vol 71 (6) ◽  
pp. 1511-1530
Author(s):  
Tao Yan ◽  
Bo Qu ◽  
Ying Wang ◽  
Guoyong Wang ◽  
Wenying Lei ◽  
...  
Keyword(s):  
Design Method ◽  
Phase Relationship ◽  
Satellite System ◽  
Single Frequency ◽  
Design Framework ◽  
Signal Design ◽  
Dual Frequency ◽  
Binary Offset Carrier ◽  
Constant Envelope ◽  
Special Cases

In the field of modernised Global Navigation Satellite System (GNSS) signal design, several Dual-frequency Constant Envelope Multiplexing (DCEM) methods have been recently proposed. However, the existing DCEM methods, such as Alternative Binary Offset Carrier (AltBOC), generalised AltBOC and Asymmetric Constant Envelope Binary Offset Carrier (ACE-BOC), are only applied in some special cases. In this paper, we present a unified DCEM design framework for GNSS signals. The existing DCEM methods can be unified in this framework. First, the signal components at two carrier frequencies are combined into two single-frequency constant envelope signals. Then, the linear sum of dual-frequency signals with non-constant envelopes is obtained. Finally, the linear sum is converted into the corresponding DCEM signal by solving an optimisation problem. The proposed design framework has no strict constraints on the number, power ratio and phase relationship of the signal components. Moreover, some special design cases under this framework are also analysed in detail. The analytical results show that the proposed design method can reach higher multiplexing efficiency compared with the existing methods. Based on the proposed method, we suggest a scheme to multiplex the BeiDou regional signals and global signals at the B2 frequency. The simulation results of correlation functions and Power Spectrum Density (PSD) verify the correctness and effectiveness of the proposed design method.

Signal Structure and Simulation of Compass Satellite Navigation System

2013 ◽  
Vol 390 ◽  
pp. 485-489
Author(s):  
Z. Huang ◽  
H. Yuan
Keyword(s):  
Navigation System ◽  
Satellite Navigation ◽  
Satellite System ◽  
Signal Design ◽  
Characteristic Analysis ◽  
Binary Offset Carrier ◽  
Satellite Navigation System ◽  
Signal Structure ◽  
Power Spectral ◽  
Compass System

Due to Chinas compass satellite navigation system which is under development, signals will be designed to obey some constraints and cooperate with other satellite system. Binary offset carrier BOC characterizing good correlation, band sharing and spectral separability is proposed for Compass system. Signal structure and development of Compass system is first analyzed in this paper, and then the principles of several BOC modulations are elaborated. The emphasis is put on a characteristic analysis of power spectral density and autocorrelation function. Further, the frequency spectrum of AltBOC modulation is simulated with Matlab due to B2 signal structure. The simulation results will be instructive meaning for compass phase Ш signal design and engineer implementation.

Phase-aligned Dual-frequency Constant Envelope Multiplexing Technique for GNSS Signals

2018 ◽  
Vol 71 (4) ◽  
pp. 899-918
Author(s):  
Zhihui Zhou ◽  
Zuping Tang ◽  
Jiaolong Wei ◽  
Xuan Xia ◽  
Tao Yan
Keyword(s):  
Phase Relationship ◽  
Global Navigation Satellite Systems ◽  
Lookup Table ◽  
Signal Design ◽  
Dual Frequency ◽  
Binary Offset Carrier ◽  
Signal Model ◽  
Frequency Signal ◽  
Satellite Systems ◽  
Constant Envelope

In the new generation of Global Navigation Satellite Systems (GNSS), dual-frequency constant envelope multiplexing is widely desired and is becoming an important subject in signal design. Considerable work has been devoted to multiplexing for the Alternative Binary Offset Carrier (AltBOC)-like signal model, for which each sideband consists of two or fewer signal components. In this paper, a phase-aligned dual-frequency constant envelope multiplexing technique is proposed for a general dual-frequency signal model. This multiplexing technique can be used to combine two constant-envelope-modulated signals in two sidebands into a composite signal with a constant envelope, where the constant-envelope-modulated signal in each sideband consists of an arbitrary number of signal components with an arbitrary power ratio and phase relationship among the signal components. A Lookup Table (LUT)-based signal generation method is also proposed, for which the required driving clock rate of the signal generator can be flexibly adjusted to meet the requirements of the satellite payload. Applications for the AltBOC-like signal model and a general dual-frequency signal model in the Beidou B1 band validate the flexibility and high multiplexing efficiency of our method. Specifically, AltBOC is a special case of the proposed method.

Multicarrier constant envelope OFDM signal design for radar applications

2010 ◽  
Vol 64 (11) ◽  
pp. 999-1008 ◽  
Author(s):  
Reza Mohseni ◽  
Abbas Sheikhi ◽  
Mohammad Ali Masnadi-Shirazi
Keyword(s):  
Signal Design ◽  
Constant Envelope ◽  
Ofdm Signal ◽  
Radar Applications

Numerical Simulation Analysis of Bearing Characteristics on Super-Large Diameter Rock Socketed Pile

2014 ◽  
Vol 580-583 ◽  
pp. 432-435 ◽  
Author(s):  
Cheng Zhong Gong ◽  
Chun Lin He ◽  
Ming Xing Zhu
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Large Diameter ◽  
Flow Analysis ◽  
Test Method ◽  
Main Stress ◽  
Pile Cap ◽  
Pile Caps ◽  
S Curve ◽  
Stress Flow

Wujiang Bridge is located on the Wujiang River in Chongqing Province in China. Based on test method of numerical simulation, the bearing characteristics of this large-diameter rock-socket pile with super-thick pile caps have been analyzed, including pile foundation load-bearing characteristics, pile-soil load sharing, and stress flow analysis of thick pile caps. The results indicated that Q-s curve of this kind of pile is approximate to linear. Under the action of ultimate load, the main load was supported by pile end résistance. And according to main stress distribution of pile cap, there is an obvious spatial truss effect phenomenon in it.

scholarly journals A Quasi-constant Envelope Multiplexing Technique for GNSS Signals

2015 ◽  
Vol 68 (4) ◽  
pp. 791-808 ◽  
Author(s):  
Tao Yan ◽  
Zuping Tang ◽  
Jiaolong Wei ◽  
Bo Qu ◽  
Zhihui Zhou
Keyword(s):  
Satellite System ◽  
Significant Feature ◽  
Constant Envelope ◽  
Modulation Techniques ◽  
Combining Efficiency ◽  
The First Variation ◽  
Global Navigation Satellite ◽  
The Second Variation ◽  
Numerical Optimisation ◽  
Composite Signal

A significant feature of the modernised Global Navigation Satellite System (GNSS) signals is that there are multiple signal components needing to be transmitted on a carrier frequency. How to combine these signal components into a constant envelope composite signal is a challenge. Existing constant envelope modulation techniques have some limitations, and are not effective enough. To solve this problem, we propose a quasi-constant-envelope multiplexing technique in this paper. The proposed method is based on numerical optimisation, and can work in two ways. The corresponding objective functions are provided. To verify the performance of the proposed method, we present three application examples. Results show that the first variation of our method can reach the same combining performance as Phase-Optimised Constant-Envelope Transmission (POCET). In the second variation, the combining efficiency can be pre-set. We can reach higher combining efficiency than POCET, and the envelope of the composite signal becomes quasi-constant. Furthermore, the inter-modulation signals in the final composite signal are adjustable. With the help of the proposed method, we can learn more details of the combining scheme than with POCET.

scholarly journals Analysis on the Potential Performance of GPS and Galileo Precise Point Positioning using Simulated Real-Time Products

2018 ◽  
Vol 72 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Francesco Basile ◽  
Terry Moore ◽  
Chris Hill
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Convergence Time ◽  
Alternative Methods ◽  
International Gnss Service ◽  
Binary Offset Carrier ◽  
Time Service ◽  
Point Positioning ◽  
The Impact

With the evolving Global Navigation Satellite System (GNSS) landscape, the International GNSS Service (IGS) has started the Multi-GNSS Experiment (MGEX) to produce precise products for new generation systems. Various analysis centres are working on the estimation of precise orbits, clocks and bias for Galileo, Beidou and Quasi-Zenith Satellite System (QZSS) satellites. However, at the moment these products can only be used for post-processing applications. Indeed, the IGS Real-Time service only broadcasts Global Positioning System (GPS) and Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) corrections. In this research, a simulator of multi-GNSS observations and real-time precise products has been developed to analyse the performance of GPS-only, Galileo-only and GPS plus Galileo Precise Point Positioning (PPP). The error models in the simulated orbits and clocks were based on the difference between the GPS Real-Time and the Final products. Multiple scenarios were analysed, considering different signals combined in the Ionosphere Free linear combination. Results in a simulated open area environment show better performance of the Galileo-only case over the GPS-only case. Indeed, up 33% and 29% of improvement, respectively, in the accuracy level and convergence time can be observed when using the full Galileo constellation compared to GPS. The dual constellation case provides good improvements, in particular in the convergence time (47% faster than GPS). This paper will also consider the impact of different linear combinations of the Galileo signals, and the potential of the E5 Alternative Binary Offset Carrier (AltBOC) signal. Even though it is significantly more precise than E5a, the PPP performance obtained with the Galileo E1-E5a combination is either better or similar to the one with Galileo E1-E5. The reason for this inconsistency was found in the use of the ionosphere free combination with E1. Finally, alternative methods of ionosphere error mitigation are considered in order to ensure the best possible positioning performance from the Galileo E5 signal in multi-frequency PPP.

scholarly journals Detection of Induced GNSS Spoofing Using S-Curve-Bias

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 922 ◽  
Author(s):  
Wenyi Wang ◽  
Na Li ◽  
Renbiao Wu ◽  
Pau Closas
Keyword(s):  
Detection Method ◽  
Satellite System ◽  
Adjustment Process ◽  
Dynamic Nature ◽  
Correct Position ◽  
Tracking Loops ◽  
False Position ◽  
Series Of Experiments ◽  
S Curve ◽  
Global Navigation Satellite

In Global Navigation Satellite System (GNSS), a spoofing attack consists of forged signals which possibly cause the attacked receivers to deduce a false position, a false clock, or both. In contrast to simplistic spoofing, the induced spoofing captures the victim tracking loops by gradually adjusting it’s parameters, e.g., code phase and power. Then the victims smoothly deviates from the correct position or timing. Therefore, it is more difficult to detect the induced spoofing than the simplistic one. In this paper, by utilizing the dynamic nature of such gradual adjustment process, an induced spoofing detection method is proposed based on the S-curve-bias (SCB). Firstly, SCB in the inducing process is theoretically derived. Then, in order to detect the induced spoofing, a detection metric is defined. After that, a series of experiments using the Texas spoofing test battery (TEXBAT) are performed to demonstrate the effectiveness of the proposed algorithm.

scholarly journals Galileo E5 AltBOC Signals: Application for Single-Frequency Total Electron Content Estimations

2021 ◽  
Vol 13 (19) ◽  
pp. 3973
Author(s):  
Artem M. Padokhin ◽  
Anna A. Mylnikova ◽  
Yury V. Yasyukevich ◽  
Yury V. Morozov ◽  
Gregory A. Kurbatov ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Noise Level ◽  
Satellite System ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Binary Offset Carrier ◽  
Total Electron ◽  
Galileo E5 ◽  
Global Navigation Satellite

Global navigation satellite system signals are known to be an efficient tool to monitor the Earth ionosphere. We suggest Galileo E5 AltBOC phase and pseudorange observables— a single-frequency combination—to estimate the ionospheric total electron content (TEC). We performed a one-month campaign in September 2020 to compare the noise level for different TEC estimations based on single-frequency and dual-frequency data. Unlike GPS, GLONASS, or Galileo E5a and E5b single-frequency TEC estimations (involving signals with binary and quadrature phase-shift keying, such as BPSK and QPSK, or binary offset carrier (BOC) modulation), an extra wideband Galileo E5 AltBOC signal provided the smallest noise level, comparable to that of dual-frequency GPS. For elevation higher than 60 degrees, the 100-sec root-mean-square (RMS) of TEC, an estimated TEC noise proxy, was as follows for different signals: ~0.05 TECU for Galileo E5 AltBOC, 0.09 TECU for GPS L5, ~0.1TECU for Galileo E5a/E5b BPSK, and 0.85 TECU for Galileo E1 CBOC. Dual-frequency phase combinations provided RMS values of 0.03 TECU for Galileo E1/E5, 0.03 and 0.07 TECU for GPS L1/L2 and L1/L5. At low elevations, E5 AltBOC provided at least twice less single-frequency TEC noise as compared with data obtained from E5a or E5b. The short dataset of our study could limit the obtained estimates; however, we expect that the AltBOC single-frequency TEC will still surpass the BPSK analogue in noise parameters when the solar cycle evolves and geomagnetic activity increases. Therefore, AltBOC signals could advance geoscience.

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