scholarly journals Indoor Carrier Phase Positioning Technology Based on OFDM System

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6731
Author(s):  
Zhenyu Zhang ◽  
Shaoli Kang ◽  
Xiang Zhang
Keyword(s):  
High Resolution ◽  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Phase Measurement ◽  
Research Direction ◽  
Global Navigation Satellite Systems ◽  
Integer Ambiguity ◽  
Ofdm Systems ◽  
Carrier Phase Measurement ◽  
Phase Measurements

Carrier phase measurement is a ranging technique that uses the receiver to determine the phase difference between the received signal and the transmitted signal. Carrier phase ranging has a high resolution; thus, it is an important research direction for high precision positioning. It is widely used in global navigation satellite systems (GNSS) systems but is not yet commonly used inwireless orthogonal frequency division multiplex (OFDM) systems. Applying carrier phase technology to OFDM systems can significantly improve positioning accuracy. Like GNSS carrier phase positioning, using the OFDM carrier phase for positioning has the following two problems. First, multipath and non-line-of-sight (NLOS) propagation have severe effects on carrier phase measurements. Secondly, ambiguity resolution is also a primary issue in the carrier phase positioning. This paper presents a ranging scheme based on the carrier phase in a multipath environment. Moreover, an algorithm based on the extended Kalman filter (EKF) is developed for fast integer ambiguity resolution and NLOS error mitigation. The simulation results show that the EKF algorithm proposed in this paper solves the integer ambiguity quickly. Further, the high-resolution carrier phase measurements combined with the accurately estimated integer ambiguity lead to less than 30-centimeter positioning error for 90% of the terminals. In conclusion, the presented methods gain excellent performance, even when NLOS error occur.

scholarly journals Performance Improvement of Time-Differenced Carrier Phase Measurement-Based Integrated GPS/INS Considering Noise Correlation

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3084 ◽  
Author(s):  
Jungbeom Kim ◽  
Younsil Kim ◽  
Junesol Song ◽  
Donguk Kim ◽  
Minhuck Park ◽  
...  
Keyword(s):  
Navigation System ◽  
Carrier Phase ◽  
Phase Measurement ◽  
Integrated System ◽  
Integer Ambiguity ◽  
Noise Correlation ◽  
Carrier Phase Measurement ◽  
Phase Measurements ◽  
Performance Improvements ◽  
Global Positioning

In this study, we combined a time-differenced carrier phase (TDCP)-based global positioning system (GPS) with an inertial navigation system (INS) to form an integrated system that appropriately considers noise correlation. The TDCP-based navigation system can determine positions precisely based on high-quality carrier phase measurements without difficulty resolving integer ambiguity. Because the TDCP system contains current and previous information that violate the format of the conventional Kalman filter, a delayed state filter that considers the correlation between process and measurement noise is utilized to improve the accuracy and reliability of the TDCP-based GPS/INS. The results of a dynamic simulation and an experiment conducted to verify the efficacy of the proposed system indicate that it can achieve performance improvements of up to 70% and 60%, respectively, compared to the conventional algorithm.

scholarly journals Initial Assessment of the LEO Based Navigation Signal Augmentation System from Luojia-1A Satellite

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3919 ◽  
Author(s):  
Lei Wang ◽  
Ruizhi Chen ◽  
Deren Li ◽  
Guo Zhang ◽  
Xin Shen ◽  
...  
Keyword(s):  
Carrier Phase ◽  
Phase Measurement ◽  
Global Navigation Satellite Systems ◽  
Initial Assessment ◽  
Dual Frequency ◽  
Carrier Phase Measurement ◽  
Phase Measurements ◽  
Satellite Systems ◽  
Navigation Signal ◽  
Global Navigation Satellite

A low Earth orbiter (LEO)-based navigation signal augmentation system is considered as a complementary of current global navigation satellite systems (GNSS), which can accelerate precise positioning convergence, strengthen the signal power, and improve signal quality. Wuhan University is dedicated to LEO-based navigation signal augmentation research and launched one scientific experimental satellite named Luojia-1A. The satellite is capable of broadcasting dual-frequency band ranging signals over China. The initial performance of the Luojia-1A satellite navigation augmentation system is assessed in this study. The ground tests indicate that the phase noise of the oscillator is sufficiently low to support the intended applications. The field ranging tests achieve 2.6 m and 0.013 m ranging precision for the pseudorange and carrier phase measurements, respectively. The in-orbit test shows that the internal precision of the ephemeris is approximate 0.1 m and the clock stability is 3 × 10−10. The pseudorange and carrier phase measurement noise evaluated from the geometry-free combination is about 3.3 m and 1.8 cm. Overall, the Luojia-1A navigation augmentation system is capable of providing useable LEO navigation augmentation signals with the empirical user equivalent ranging error (UERE) no worse than 3.6 m, which can be integrated with existing GNSS to improve the real-time navigation performance.

scholarly journals Partial Carrier-Phase Integer Ambiguity Resolution for High Accuracy GNSS Positioning

2020 ◽  
Author(s):  
Andreas Brack
Keyword(s):  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Real Data ◽  
Global Navigation Satellite Systems ◽  
Integer Ambiguity ◽  
Phase Measurements ◽  
Satellite Systems ◽  
Partial Ambiguity Resolution ◽  
Gnss Positioning ◽  
Global Navigation Satellite

Global navigation satellite systems provide ranging based positioning and timing services. The use of the periodic carrier-phase signals is the key to fast and accurate solutions, given that the inherent ambiguities of the carrier-phase measurements are correctly resolved. The idea of partial ambiguity resolution is to resolve a subset of all ambiguities, which enables faster solutions but does not fully exploit the high precision of the carrier-phase measurements. Theory, methods, and algorithms for partial ambiguity resolution are discussed and analyzed with simulated and real data.

scholarly journals Carrier Phase Measurement in IRNSS using Antenna swapping Method

2019 ◽  
Vol 8 (3) ◽  
pp. 1685-1688
Keyword(s):  
Carrier Frequency ◽  
Carrier Phase ◽  
Phase Measurement ◽  
Satellite System ◽  
Space Research ◽  
Integer Ambiguity ◽  
Navigation Satellite ◽  
Carrier Phase Measurement ◽  
Accurate Position

Indian has been established its regional navigational satellite system i.e., IRNSS (Indian space research navigation satellite system). It is launched successfully with seven satellites. It provide accurate position to user in Indian and up to 1500km around the India. In this paper, calculated the integer ambiguity (N) which is one of the parameter of the carrier phase measurement. Carrier phase measurement is measure the range between the satellite and receiver expressed units of cycle of the carrier frequency.

scholarly journals Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning

2021 ◽  
Vol 13 (15) ◽  
pp. 2904
Author(s):  
Juan Manuel Castro-Arvizu ◽  
Daniel Medina ◽  
Ralf Ziebold ◽  
Jordi Vilà-Valls ◽  
Eric Chaumette ◽  
...  
Keyword(s):  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Real Data ◽  
Global Navigation Satellite Systems ◽  
Integer Ambiguity ◽  
Satellite Systems ◽  
Partial Ambiguity Resolution ◽  
Complete Vector ◽  
Global Navigation Satellite ◽  
Long Baselines

The use of carrier phase data is the main driver for high-precision Global Navigation Satellite Systems (GNSS) positioning solutions, such as Real-Time Kinematic (RTK). However, carrier phase observations are ambiguous by an unknown number of cycles, and their use in RTK relies on the process of mapping real-valued ambiguities to integer ones, so-called Integer Ambiguity Resolution (IAR). The main goal of IAR is to enhance the position solution by virtue of its correlation with the estimated integer ambiguities. With the deployment of new GNSS constellations and frequencies, a large number of observations is available. While this is generally positive, positioning in medium and long baselines is challenging due to the atmospheric residuals. In this context, the process of solving the complete set of ambiguities, so-called Full Ambiguity Resolution (FAR), is limiting and may lead to a decreased availability of precise positioning. Alternatively, Partial Ambiguity Resolution (PAR) relaxes the condition of estimating the complete vector of ambiguities and, instead, finds a subset of them to maximize the availability. This article reviews the state-of-the-art PAR schemes, addresses the analytical performance of a PAR estimator following a generalization of the Cramér–Rao Bound (CRB) for the RTK problem, and introduces Precision-Driven PAR (PD-PAR). The latter constitutes a new PAR scheme which employs the formal precision of the (potentially fixed) positioning solution as selection criteria for the subset of ambiguities to fix. Numerical simulations are used to showcase the performance of conventional FAR and FAR approaches, and the proposed PD-PAR against the generalized CRB associated with PAR problems. Real-data experimental analysis for a medium baseline complements the synthetic scenario. The results demonstrate that (i) the generalization for the RTK CRB constitutes a valid lower bound to assess the asymptotic behavior of PAR estimators, and (ii) the proposed PD-PAR technique outperforms existing FAR and PAR solutions as a non-recursive estimator for medium and long baselines.

scholarly journals The performance of bds relative positioning usage with real observation data

2014 ◽  
Vol 20 (2) ◽  
pp. 223-236 ◽  
Author(s):  
Xu Tang ◽  
Xiufeng He ◽  
Samuel A. Andam-Akorful
Keyword(s):  
Carrier Phase ◽  
Phase Measurement ◽  
Observation Data ◽  
Relative Positioning ◽  
Carrier Phase Measurement ◽  
Phase Measurements ◽  
Short Baselines ◽  
Better Than

With the first phase of COMPASS/BeiDou-2 (BDS) completed, the assessment of positioning performance and the characterization of its system are analyzed and presented. Pseudo-range and carrier phase measurements modulated on B1 and B2 have been collected in Shanghai, from 00:00 to 24:00 on 28 December, 2012. Compared with GPS, visibility and measurement quality of BDS's GEO, IGSO and MEO satellites are analyzed. DOP during the whole orbital period is also analyzed the results demonstrate that BDS's HDOP is better than GPS's one, but VDOP opposite. Furthermore, the result of positioning is also presented and analyzed. Short baselines are estimated by standalone BDS and GPS's carrier phase measurement, respectively, using 48 segmentations of observations during a whole day (24 hours, each segmentation, is about 30 minutes observation). The analysis of static relative positioning demonstrates that BDS could achieve to millimeter level, corresponding to GPS. Kinematic result is produced by double differenced carrier phase observations with the ambiguities fixed under the constraint of precise short baseline.The result shows that the centimeter accuracy could be achieved. When comparing the results of kinematic baseline solutions, performance of BDS is worse than GPS on North and Up components, but oppositely on the component of East in the kinematic baseline processing.

Low Cost AHRS Aids GPS Attitude Navigation System

2014 ◽  
Vol 536-537 ◽  
pp. 748-755
Author(s):  
Tong Yue Gao ◽  
Hai Lang Ge
Keyword(s):  
Navigation System ◽  
Carrier Phase ◽  
Phase Measurement ◽  
Low Cost ◽  
Integer Ambiguity ◽  
Baseline Length ◽  
Carrier Phase Measurement ◽  
Basic Model ◽  
Aircraft Type ◽  
Gps System

Recently, the SUAV has become the research focus at home and abroad. There is a new aircraft type: double ducted tilting Subminiature UAV system, this paper put forward a new attitude navigation system:AHRS-based low-cost GPS carrier phase orientation Navigation System. AHRS aids GPS fastly fix the attitude.This article proposed application the constraint solving the ambiguity basic model, which is based on the double differential equations of the carrier phase measurement. Then we use baseline length and the inaccurate attitude angle constraint to solver integer ambiguity. By the static experimental results show that this method is fast, effective, the AHRS-GPS system can provide high accuracy navigation for SUAV.

scholarly journals Integration and Simulations of INS/GNSS System using the Approach of Carrier Phase Measurements

2015 ◽  
Vol 4 (4) ◽  
pp. 243
Author(s):  
Khan Badshah ◽  
Qin Yongyuan
Keyword(s):  
Kalman Filtering ◽  
Carrier Phase ◽  
Closed Loop ◽  
Position Estimation ◽  
Integrated System ◽  
Integer Ambiguity ◽  
Font Size ◽  
Phase Measurements ◽  
Simulation Results ◽  
Lever Arm Effect

<p class="MsoNormal" style="margin-top: 12.0pt; margin-right: 0in; margin-bottom: 6.0pt; margin-left: 0in; text-align: justify;"><em><span style="font-size: 9.0pt; font-family: &quot;Arial&quot;,sans-serif; mso-ascii-theme-font: minor-bidi; mso-hansi-theme-font: minor-bidi; mso-bidi-theme-font: minor-bidi;" lang="EN-GB">This paper discusses the techniques of attitude, velocity ad position estimation from GNSS carrier phase measurements, and investigates the performance of the lower precision MEMS-based INS/GNSS system based on carrier phase measurements. Double differenced carrier phase measurements provide more accurate velocity and position estimation compared to code and Doppler measurements. However, integer ambiguity is required to be removed for precise positioning. Multiples<span style="color: red;"> </span>antennae approach is used to derive the attitude information from carrier phase measurements in order to control the large initial misalignment angles for initialization of the integration process or to utilize during benign dynamics. Lever arm effect is considered to compensate for the separation of GNSS antenna and IMU location. The derived three GNSS observables are used to correct the INS through optimal Kalman filtering in a closed loop. Simulation results indicates the effectiveness of the integrated system for airborne as well as for land navigation vehicles</span></em><span lang="EN-GB">. </span></p><div id="_mcePaste" class="mcePaste" style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow: hidden;"><p class="MsoNormal" style="margin-top: 12.0pt; margin-right: 0in; margin-bottom: 6.0pt; margin-left: 0in; text-align: justify;"><em><span style="font-size: 9.0pt; font-family: &quot;Arial&quot;,sans-serif; mso-ascii-theme-font: minor-bidi; mso-hansi-theme-font: minor-bidi; mso-bidi-theme-font: minor-bidi;" lang="EN-GB">This paper discusses the techniques of attitude, velocity ad position estimation from GNSS carrier phase measurements, and investigates the performance of the lower precision MEMS based INS/GNSS system based on carrier phase measurements. Double differenced carrier phase measurements provide more accurate velocity and position estimation compared to code and Doppler measurements. However, integer ambiguity is required to be removed for precise positioning. Multiples<span style="color: red;"> </span>antennae approach is used to derive the attitude information from carrier phase measurements in order to control the large initial misalignment angles for initialization of the integration process or to utilize during benign dynamics. Lever arm effect is considered to compensate for the separation of GNSS antenna and IMU location. The derived three GNSS observables are used to correct the INS through optimal Kalman filtering in a closed loop. Simulation results indicates the effectiveness of the integrated system for airborne as well as for land navigation vehicles</span></em><span lang="EN-GB">. </span></p></div>

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