scholarly journals Walker: Continuous and Precise Navigation by Fusing GNSS and MEMS in Smartphone Chipsets for Pedestrians

2019 ◽  
Vol 11 (2) ◽  
pp. 139 ◽  
Author(s):  
Feng Zhu ◽  
Xianlu Tao ◽  
Wanke Liu ◽  
Xiang Shi ◽  
Fuhong Wang ◽  
...  
Keyword(s):  
Carrier Phase ◽  
Signal To Noise Ratio ◽  
Single Point ◽  
Dead Reckoning ◽  
Smartphone Application ◽  
Satellite System ◽  
Portable Devices ◽  
Navigation Solution ◽  
Global Navigation Satellite ◽  
Gnss Observations

The continual miniaturization of mass-market sensors built in mobile intelligent terminals has inspired the development of accurate and continuous navigation solution for portable devices. With the release of Global Navigation Satellite System (GNSS) observations from the Android Nougat system, smartphones can provide pseudorange, Doppler, and carrier phase observations of GNSS. However, it is still a challenge to achieve the seamless positioning of consumer applications, especially in environments where GNSS signals suffer from a low signal-to-noise ratio and severe multipath. This paper introduces a dedicated android smartphone application called Walker that integrates the GNSS navigation solution and MEMS (micro-electromechanical systems) sensors to enable continuous and precise pedestrian navigation. Firstly, we introduce the generation of GNSS and MEMS observations, in addition to the architecture of Walker application. Then the core algorithm in Walker is given, including the time-differenced carrier phase improved GNSS single-point positioning and the integration of GNSS and Pedestrian Dead Reckoning (PDR). Finally, the Walker application is tested and the observations of GNSS and MEMS are assessed. The static experiment shows that, with GNSS observations, the RMS (root mean square) values of east, north, and up positioning error are 0.49 m, 0.37 m, and 1.01 m, respectively. Furthermore, the kinematic experiment verifies that the proposed method is capable of obtaining accuracy within 1–3 m for smooth and continuous navigation.

scholarly journals A Robust GNSS/PDR Integration Scheme with GRU-Based Zero-Velocity Detection for Mass-Pedestrians

2022 ◽  
Vol 14 (2) ◽  
pp. 300
Author(s):  
Dongpeng Xie ◽  
Jinguang Jiang ◽  
Jiaji Wu ◽  
Peihui Yan ◽  
Yanan Tang ◽  
...  
Keyword(s):  
Low Cost ◽  
Single Point ◽  
Dead Reckoning ◽  
Satellite System ◽  
Integration Scheme ◽  
Fusion Algorithm ◽  
Zero Velocity ◽  
Single Antenna ◽  
Other Information ◽  
Global Navigation Satellite

Aiming at the problem of high-precision positioning of mass-pedestrians with low-cost sensors, a robust single-antenna Global Navigation Satellite System (GNSS)/Pedestrian Dead Reckoning (PDR) integration scheme is proposed with Gate Recurrent Unit (GRU)-based zero-velocity detector. Based on the foot-mounted pedestrian navigation system, the error state extended Kalman filter (EKF) framework is used to fuse GNSS position, zero-velocity state, barometer elevation, and other information. The main algorithms include improved carrier phase smoothing pseudo-range GNSS single-point positioning, GRU-based zero-velocity detection, and adaptive fusion algorithm of GNSS and PDR. Finally, the scheme was tested. The root mean square error (RMSE) of the horizontal error in the open and complex environments is lower than 1 m and 1.5 m respectively. In the indoor elevation experiment where the elevation difference of upstairs and downstairs exceeds 25 m, the elevation error is lower than 1 m. This result can provide technical reference for the accurate and continuous acquisition of public pedestrian location information.

scholarly journals Ionosphere-Constrained Single-Frequency PPP with an Android Smartphone and Assessment of GNSS Observations

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5917
Author(s):  
Guangxing Wang ◽  
Yadong Bo ◽  
Qiang Yu ◽  
Min Li ◽  
Zhihao Yin ◽  
...  
Keyword(s):  
Single Point ◽  
Application Programming Interface ◽  
Satellite System ◽  
Single Frequency ◽  
Dual Frequency ◽  
Application Programming ◽  
Point Positioning ◽  
Global Navigation Satellite ◽  
Gnss Observations ◽  
Better Than

With the development of Global Navigation Satellite System (GNSS) and the opening of Application Programming Interface (API) of Android terminals, the positioning research of Android terminals has attracted the attention of GNSS community. In this paper, three static experiments were conducted to analyze the raw GNSS observations quality and positioning performances of the smartphones. For the two experimental smartphones, the numbers of visible satellites with dual-frequency signals are unstable and not enough for dual-frequency Precise Point Positioning (PPP) processing all through the day. Therefore, the ionosphere-constrained single-frequency PPP model was employed to improve the positioning with the smartphones, and its performance was evaluated and compared with those of the Single Point Positioning (SPP) and the traditional PPP models. The results show that horizontal positioning accuracies of the smartphones with the improved PPP model are better than 1 m, while those with the SPP and the traditional PPP models are about 2 m.

scholarly journals Assessment of Dual Frequency GNSS Observations from a Xiaomi Mi 8 Android Smartphone and Positioning Performance Analysis

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 91 ◽  
Author(s):  
Umberto Robustelli ◽  
Valerio Baiocchi ◽  
Giovanni Pugliano
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Global Navigation Satellite System ◽  
Carrier Phase ◽  
Single Point ◽  
Satellite System ◽  
Navigation Satellite ◽  
Mean Square ◽  
Dual Frequency ◽  
Global Navigation Satellite

On May 2018 the world’s first dual-frequency Global Navigation Satellite System (GNSS) smartphone produced by Xiaomi equipped with a Broadcom BCM47755 chip was launched. It is able to receive L1/E1/ and L5/E5 signals from GPS, Galileo, Beidou, and GLONASS (GLObal NAvigation Satellite System) satellites. The main aim of this work is to achieve the phone’s position by using multi-constellation, dual frequency pseudorange and carrier phase raw data collected from the smartphone. Furthermore, the availability of dual frequency raw data allows to assess the multipath performance of the device. The smartphone’s performance is compared with that of a geodetic receiver. The experiments were conducted in two different scenarios to test the smartphone under different multipath conditions. Smartphone measurements showed a lower C/N0 and higher multipath compared with those of the geodetic receiver. This produced negative effects on single-point positioning as showed by high root mean square error (RMS). The best positioning accuracy for single point was obtained with the E5 measurements with a DRMS (horizontal root mean square error) of 4.57 m. For E1/L1 frequency, the 2DRMS was 5.36 m. However, the Xiaomi Mi 8, thanks to the absence of the duty cycle, provided carrier phase measurements used for a static single frequency relative positioning with an achieved 2DRMS of 1.02 and 1.95 m in low and high multipath sites, respectively.

scholarly journals Real-Time Detection of Orbital Maneuvers Using Epoch-Differenced Carrier Phase Observations and Broadcast Ephemeris Data: A Case Study of the BDS Dataset

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4584 ◽  
Author(s):  
Rui Tu ◽  
Rui Zhang ◽  
Lihong Fan ◽  
Junqiang Han ◽  
Pengfei Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Carrier Phase ◽  
Single Point ◽  
Satellite System ◽  
Velocity Estimation ◽  
Navigation Satellite ◽  
Orbital Maneuvers ◽  
Broadcast Ephemeris ◽  
Real Time Detection ◽  
Global Navigation Satellite

The orbital maneuvers of the global navigation satellite system (GNSSs) have a significant influence on the performance of the precise positioning, navigation, and timing (PNT) services. Because the Chinese BeiDou Navigation Satellite System (BDS) has three types of satellites in the geostationary orbit (GEO), inclined geosynchronous orbit (IGSO), and medium earth orbit (MEO) maneuvers occur more frequently. Thus, it is essential to determine an effective approach for the detection of orbital maneuvers. This study proposes a method for the detection of orbital maneuvers using epoch-differenced carrier phase observations and broadcast ephemeris data. When using the epoch-differenced velocity estimation as a basic data solution model, the time discrimination and satellite identification factors are defined and used for the real-time detection of the beginning and the pseudorandom noise code (PRN) of satellites. The datasets from four GNSS stations (WUH1, BJF1, POHN, CUT0) from the year 2016 were collected and analyzed. The validations showed that the beginning, the PRN of the orbital maneuver of the satellite can be precisely detected in real time for all GEO, IGSO, and MEO satellites, and the detected results also showed good consistency, with the beginning time at a difference of 1–2 min across different stations. The proposed approach was observed to be more sensitive, and the detected beginning time was about 30 min earlier than the single point positioning approach when the high-precision carrier phase observation was used. Thus, orbital maneuvering can be accurately detected by the proposed method. It not only improves the utilization of the collected data but also improves the performance of PNT services.

scholarly journals PERFORMANCE ANALYSIS OF SISPELSAT MSK-DGNSS RADIO SIGNAL IN PENINSULAR MALAYSIA

2018 ◽  
Vol XLII-4/W9 ◽  
pp. 57-65
Author(s):  
M. S. A. Razak ◽  
T. A. Musa ◽  
R. Othman ◽  
M. F. Yazair ◽  
A. Z. Sha’ameri ◽  
...  
Keyword(s):  
Radio Signal ◽  
Signal To Noise Ratio ◽  
Satellite System ◽  
Peninsular Malaysia ◽  
Observation Data ◽  
Navigation Solution ◽  
Shift Keying ◽  
Global Navigation Satellite ◽  
Radio Beacon ◽  
Beacon Signal

<p><strong>Abstract.</strong> The use of Global Navigation Satellite System (GNSS) has become essential in providing location based information and navigation. Due to low accuracy of navigation solution, differential technique such as radio-beacon DGNSS has been used widely to augment the user single positioning using GPS. The <i>Sistem Pelayaran Satelit</i> (SISPELSAT) is a national DGNSS radio-beacon system in Malaysia consists of four broadcasting and two monitoring stations operated and managed by Marine Department of Malaysia. It provides a range of frequency from 283.5 to 325<span class="thinspace"></span>kHz Minimum Shift Keying (MSK) radio-beacon DGNSS correction service within the shore of Peninsular Malaysia. In this study, the performance of SISPELSAT radio signal was assessed on-board of the Malaysian Vessel (MV) Pedoman and MV Pendamar. The study area covers 20<span class="thinspace"></span>km shore distance extending from shoreline of Peninsular Malaysia with continuous tracking from SISPELSAT radio beacon signal. The DGPS observation data as well as the coverage of the signal strength, signal-to-noise ratio, accuracy and DGPS status were recorded for data processing and further analysis of SISPELSAT radio signal performance.</p>

scholarly journals The Design a TDCP-Smoothed GNSS/Odometer Integration Scheme with Vehicular-Motion Constraint and Robust Regression

2020 ◽  
Vol 12 (16) ◽  
pp. 2550
Author(s):  
Kai-Wei Chiang ◽  
Yu-Hua Li ◽  
Li-Ta Hsu ◽  
Feng-Yu Chu
Keyword(s):  
State Estimation ◽  
Navigation System ◽  
Robust Regression ◽  
Single Point ◽  
Dead Reckoning ◽  
Satellite System ◽  
Least Square ◽  
Integration Scheme ◽  
Intelligent Transport System ◽  
Global Navigation Satellite

Global navigation satellite system (GNSS) is widely regarded as the primary positioning solution for intelligent transport system (ITS) applications. However, its performance could degrade, due to signal outages and faulty-signal contamination, including multipath and non-line-of-sight reception. Considering the limitation of the performance and computation loads in mass-produced automotive products, this research investigates the methods for enhancing GNSS-based solutions without significantly increasing the cost for vehicular navigation system. In this study, the measurement technique of the odometer in modern vehicle designs is selected to integrate the GNSS information, without using an inertial navigation system. Three techniques are implemented to improve positioning accuracy; (a) Time-differenced carrier phase (TDCP) based filter: A state-augmented extended Kalman filter is designed to incorporate TDCP measurements for maximizing the effectiveness of phase-smoothing; (b) odometer-aided constraints: The aiding measurement from odometer utilizing forward speed with the lateral constraint enhances the state estimation; the information based on vehicular motion, comprising the zero-velocity constraint, fault detection and exclusion, and dead reckoning, maintains the stability of the positioning solution; (c) robust regression: A weighted-least-square based robust regression as a measurement-quality assessment is applied to adjust the weightings of the measurements adaptively. Experimental results in a GNSS-challenging environment indicate that, based on the single-point-positioning mode with an automotive-grade receiver, the combination of the proposed methods presented a root-mean-square error of 2.51 m, 3.63 m, 1.63 m, and 1.95 m for the horizontal, vertical, forward, and lateral directions, with improvements of 35.1%, 49.6%, 45.3%, and 21.1%, respectively. The statistical analysis exhibits 97.3% state estimation result in the horizontal direction for the percentage of epochs that had errors of less than 5 m, presenting that after the intervention of proposed methods, the positioning performance can fulfill the requirements for road level applications.

On the Feasibility and Applicability of Multipath Mitigation Maps as an IGS Product

2020 ◽  
Author(s):  
Addisu Hunegnaw ◽  
Yohannes Getachew Ejigu ◽  
Felix Norman Teferle ◽  
Gunnar Elgered
Keyword(s):  
Carrier Phase ◽  
Satellite System ◽  
Screening Tests ◽  
International Gnss Service ◽  
Multipath Mitigation ◽  
Harmonic Signals ◽  
The One ◽  
Global Navigation Satellite ◽  
Gnss Observations

&lt;p&gt;Multipath is a largely unmodelled source of error and causes large range errors in Global Navigation Satellite System (GNSS) observations. The effects have strong site-specific characteristics and impact each receiver differently. Multipath errors can propagate and can cause in-situ position and velocity biases and are also contributing to the pervasive draconitic harmonic signals. We employ an empirical approach to reducing the effects of multipath by stacking one-way post-fit carrier phase residual observations by applying an appropriate averaging scheme. Our processing is based on static multi-GNSS observations using various scientific GNSS software packages (Bernese GNSS Software, NAPEOS, GAMIT-GLOBK, PRIDE and GINS). Our multipath stacking (MPS ) uses the stacking of individual residuals generated by variable azimuth cell size (congruent cells) by allocating carrier phase residuals in each cell, unlike fixed azimuth cell resolution in the standard MPS approaches. This reduces the binning of fewer residuals at higher elevation angles. Before stacking, we also apply rigorous statistical outlier screening tests for each one-way post-fit carrier phase residual assigned to each of the congruent cells. We thus correct the multipath effects by subtracting the stacked multipath map from the post-fit carrier phase residual. Using this technique we produce a model available in the form of the Antenna Exchange (ANTEX) file format, that can potentially be implemented in routine GNSS analysis with no or little additional overhead for individual analysis centers (ACs).&lt;/p&gt;&lt;p&gt;In this study, we assess the feasibility and applicability of the MPS maps as an International GNSS Service (IGS) product for routine GNSS analysis. We have selected a subset of IGS stations with and without known multipath issues in different climatic zones. We demonstrate the multipath stacking technique to result in a significant reduction of the variation in the one-way post-fit carrier phase residuals. For GPS-only solutions, the MPS technique shows a decrease of up to 30% in the RMS value of the one-way post-fit carrier phase residuals. We have also tested our MPS for other constellations such as GLONASS, Galileo and BeiDou, and combinations of these .&lt;/p&gt;

scholarly journals Improving DGNSS Performance through the Use of Network RTK Corrections

2021 ◽  
Vol 13 (9) ◽  
pp. 1621
Author(s):  
Duojie Weng ◽  
Shengyue Ji ◽  
Yangwei Lu ◽  
Wu Chen ◽  
Zhihua Li
Keyword(s):  
Carrier Phase ◽  
Local Area ◽  
Satellite System ◽  
High Accuracy ◽  
Single Frequency ◽  
Baseline Length ◽  
Low Latitude ◽  
Phase Measurements ◽  
Network Rtk ◽  
Global Navigation Satellite

The differential global navigation satellite system (DGNSS) is an enhancement system that is widely used to improve the accuracy of single-frequency receivers. However, distance-dependent errors are not considered in conventional DGNSS, and DGNSS accuracy decreases when baseline length increases. In network real-time kinematic (RTK) positioning, distance-dependent errors are accurately modelled to enable ambiguity resolution on the user side, and standard Radio Technical Commission for Maritime Services (RTCM) formats have also been developed to describe the spatial characteristics of distance-dependent errors. However, the network RTK service was mainly developed for carrier-phase measurements on professional user receivers. The purpose of this study was to modify the local-area DGNSS through the use of network RTK corrections. Distance-dependent errors can be reduced, and accuracy for a longer baseline length can be improved. The results in the low-latitude areas showed that the accuracy of the modified DGNSS could be improved by more than 50% for a 17.9 km baseline during solar active years. The method in this paper extends the use of available network RTK corrections with high accuracy to normal local-area DGNSS applications.

scholarly journals Characterization of multi-scale ionospheric irregularities using ground-based and space-based GNSS observations

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
YuXiang Peng ◽  
Wayne A Scales ◽  
Michael D Hartinger ◽  
Zhonghua Xu ◽  
Shane Coyle
Keyword(s):  
Formation Flying ◽  
Satellite System ◽  
Ionospheric Irregularities ◽  
Mission Design ◽  
Electron Content ◽  
Total Electron ◽  
Spatial And Temporal Scales ◽  
Multi Scale ◽  
Global Navigation Satellite ◽  
Gnss Observations

AbstractIonospheric irregularities can adversely affect the performance of Global Navigation Satellite System (GNSS). However, this opens the possibility of using GNSS as an effective ionospheric remote sensing tool. Despite ionospheric monitoring has been undertaken for decades, these irregularities in multiple spatial and temporal scales are still not fully understood. This paper reviews Virginia Tech’s recent studies on multi-scale ionospheric irregularities using ground-based and space-based GNSS observations. First, the relevant background of ionospheric irregularities and their impact on GNSS signals is reviewed. Next, three topics of ground-based observations of ionospheric irregularities for which GNSS and other ground-based techniques are used simultaneously are reviewed. Both passive and active measurements in high-latitude regions are covered. Modelling and observations in mid-latitude regions are considered as well. Emphasis is placed on the increased capability of assessing the multi-scale nature of ionospheric irregularities using other traditional techniques (e.g., radar, magnetometer, high frequency receivers) as well as GNSS observations (e.g., Total-Electron-Content or TEC, scintillation). Besides ground-based observations, recent advances in GNSS space-based ionospheric measurements are briefly reviewed. Finally, a new space-based ionospheric observation technique using GNSS-based spacecraft formation flying and a differential TEC method is demonstrated using the newly developed Virginia Tech Formation Flying Testbed (VTFFTB). Based on multi-constellation multi-band GNSS, the VTFFTB has been developed into a hardware-in-the-loop simulation testbed with external high-fidelity global ionospheric model(s) for 3-satellite formation flying, which can potentially be used for new multi-scale ionospheric measurement mission design.

scholarly journals Many Ways Lead to the Goal—Possibilities of Autonomous and Infrastructure-Based Indoor Positioning

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 397
Author(s):  
Hossein Shoushtari ◽  
Thomas Willemsen ◽  
Harald Sternberg
Keyword(s):  
Mobile Networks ◽  
Dead Reckoning ◽  
Simulated Data ◽  
Minimum Cost ◽  
Cost Effective ◽  
Satellite System ◽  
Position Estimation ◽  
Robust Solution ◽  
Position Data ◽  
Global Navigation Satellite

There are many ways to navigate in Global Navigation Satellite System-(GNSS) shaded areas. Reliable indoor pedestrian navigation has been a central aim of technology researchers in recent years; however, there still exist open challenges requiring re-examination and evaluation. In this paper, a novel dataset is used to evaluate common approaches for autonomous and infrastructure-based positioning methods. The autonomous variant is the most cost-effective realization; however, realizations using the real test data demonstrate that the use of only autonomous solutions cannot always provide a robust solution. Therefore, correction through the use of infrastructure-based position estimation based on smartphone technology is discussed. This approach invokes the minimum cost when using existing infrastructure, whereby Pedestrian Dead Reckoning (PDR) forms the basis of the autonomous position estimation. Realizations with Particle Filters (PF) and a topological approach are presented and discussed. Floor plans and routing graphs are used, in this case, to support PDR positioning. The results show that the positioning model loses stability after a given period of time. Fifth Generation (5G) mobile networks can enable this feature, as well as a massive number of use-cases, which would benefit from user position data. Therefore, a fusion concept of PDR and 5G is presented, the benefit of which is demonstrated using the simulated data. Subsequently, the first implementation of PDR with 5G positioning using PF is carried out.

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