Institute Of Navigation Research Articles

Fusion of 3D GIS, Vision, Inertial and Magnetic Data for Improved Urban Pedestrian Navigation and Augmented Reality Applications

n the context of pedestrian navigation and Augmented Reality applications in urban environments, we propose to fuse the pose estimated through a vision process, thanks to a precisely known 3D model, with inertial and magnetic measurements. First, this allows for updating a Pedestrian DeadReckoning process and improving the positioning accuracy. Second, a trusted pose estimate allows us to reproject 3D Geographical Information System content in Augmented Reality with qualified confidence. Because 3D Geographical Information System data are provided by many sources inducing an inhomogeneous precision and level of quality, being able to qualify these 3D contents is important to validate their relevance to use them. A long pedestrian path of 3 km in an urban environment with a sparsely known 3D model of urban furniture was conducted. This has permitted validation of the contribution of sensor fusion that improves the positioning accuracy and allows characterization of the 3D Geographical Information System content directly onsite using Augmented Reality. Performance is presented in terms of positioning accuracy in urban spaces. © 2018 Institute of Navigation.

Corrigendum

NAVIGATIONVolume 65, Issue 2 p. 287-288 CorrigendumFree Access Corrigendum First published: 22 July 2018 https://doi.org/10.1002/navi.246AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Performance Analysis of Optimal Combinations for Triple-Frequency BDS LEIZHENG SHU et al. (2017) 1, In the paper, “Performance Analysis of Optimal Combinations for Triple-Frequency BDS” (NAVIGATION, Vol. 64, No. 4, Winder 2017). The following information was incorrect. The author list and affiliation of the three authors were incorrectly published on page 447. The Table 2 on Page 452 was incorrectly published. The ACKNOWLEDGMENTS on page 460 was incorrectly published. The author list and affiliation were published as: Table 2. Proposed combinations including characteristics in the S1a region crossing the line k = 0 k i1 i2 i3 λ (m) n (cycle units) (length units, m) q (cycle units) (length units, m) 11 –3 –2 6 13.3206 7 93.2442 2.298 159.3939 41 –3 –1 5 3.5738 5.9161 21.1430 2.2355 41.6009 71 –3 0 4 2.0637 5 10.3185 2.1729 23.3499 18 –4 4 1 8.1403 5.7446 46.7628 2.2158 93.9224 48 –4 5 0 3.0526 6.4031 19.5461 2.1532 34.2257 –5 –5 9 3 –29.302 10.7238 −314.2290 2.1961 –335.1157 2 –6 15 –8 73.2631 18.0278 1320.773 2.1139 806.4319 LEIZHENG SHU and WENBIN WANG Key Laboratory of Space Utilization, Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing, China RAN DING Beijing Research Institute of Telemetry, Beijing, China HUABO WEI China Aeronautical Radio Electronics Research Institute, Shanghai, China They should be as: LEIZHENG SHU School of Astronautics, Beihang University, Key Laboratory of Space Utilization, Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing, China PEI CHEN School of Astronautics, Beihang University RAN DING School of Astronautics, Beihang University Beijing Research Institute of Telemetry, Beijing, China HUABO WEI School of Astronautics, Beihang University China Aeronautical Radio Electronics Research Institute, Shanghai, China WENBIN WANG Key Laboratory of Space Utilization, Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing, China CHAO HAN School of Astronautics, Beihang University, China The value of i3 on the 6th row of Table 2 on Page 452 should be corrected from 3 to -3, to avoid any further confusion to the readers. The Table 2 was published as: Table 2. Proposed combinations including characteristics in the S1a region crossing the line k = 0 k i1 i2 i3 λ (m) n (cycle units) (length units, m) q (cycle units) (length units, m) 11 –3 –2 6 13.3206 7 93.2442 2.298 159.3939 41 –3 –1 5 3.5738 5.9161 21.1430 2.2355 41.6009 71 –3 0 4 2.0637 5 10.3185 2.1729 23.3499 18 –4 4 1 8.1403 5.7446 46.7628 2.2158 93.9224 48 –4 5 0 3.0526 6.4031 19.5461 2.1532 34.2257 –5 –5 9 –3 –29.302 10.7238 −314.2290 2.1961 –335.1157 2 –6 15 –8 73.2631 18.0278 1320.773 2.1139 806.4319 Table 2 should be as: The ACKNOWLEDGMENTS were published as: The authors wish to thank Associate Professor Chen Pei of Beihang University for providing the experimental equipment and many beneficial discussions. The authors are grateful to the associate editor and two anonymous reviewers whose comments have largely contributed to the improvement of this manuscript. This work was supported in part by the Chinese Academy of Sciences (Contract No. CXJJ-16Q211) and the National Natural Science Foundation of China (Grant No. 11603057). Based on a conference paper presented at The Institute of Navigation's GNSS+ 2016, Portland, Oregon, September 2016. They should be as: The authors are grateful to the associate editor and two anonymous reviewers whose comments have largely contributed to the improvement of this manuscript. This work was supported in part by the National Natural Science Foundation of China through cooperative agreement No. 11002008 and No.11603057, and has been funded in part by the Ministry of Science and Technology of China through cooperative agreement No. 2014CB845303, by the Chinese Academy of Sciences through contract No. CXJJ-16Q211. Based on a conference paper presented at The Institute of Navigation's GNSS+2016, Portland, Oregon, September 2016. The authors apologize for these errors. REFERENCE 1Shu, L., Wang, W., Ding, R., and Wei, H., “Performance Analysis of Optimal Combinations for Triple-Frequency BDS,” NAVIGATION, Vol. 64, No. 4, Winter 2017, pp. 447- 461. Volume65, Issue2Summer 2018Pages 287-288 ReferencesRelatedInformation

Accuracy Analysis of an Integrated Inertial Navigation System in Slow Maneuvers

In-motion alignment of a strapdown inertial navigation system, during slow maneuvers, is studied. Terrestrial velocity is fed back to the navigation system to estimate and compensate for the navigation errors. Observability of the errors is analyzed since the integrated navigation system is not fully observable. Then, the accuracy bounds of the navigation system in different motion scenarios are obtained analytically. Also, in order to minimize the errors of the navigation system, special maneuvers are designed based on the analytical derivations. The analytical results, obtained using the linearized error model, are verified through nonlinear simulation of different maneuvering and non-maneuvering scenarios. It is shown that the proposed analytical method can be used to predict the errors of the navigation system with a high level of accuracy. Copyright © 2017 Institute of Navigation

Enhanced GNSS Signal Tracking in Fading Environments using Frequency Diversity

A new methodology to enhance the GNSS parameter estimation accuracy in multipath fading environments using the frequency diversity reception is proposed herein. In such environments, fading occurrences observed in different frequency bands are independent of each other. Characteristics of frequency diversity reception using GPS L1 and L2C signals in dense fading conditions are first discussed and compared with those of spatial diversity reception. Comparative analyses of characterization metrics between frequency diversity and spatial diversity signals support the argument that the former is as effective as the latter. A frequency diversity based combined tracking approach is then proposed, and the performance is evaluated using the data collected in dense foliage and residential environments. Results show that frequency diversity based combined tracking results in improved performance compared to that of single frequency tracking. 3D position error reduction achieved by the proposed method is 52% in foliage conditions and 50% in residential environments. Copyright © 2017 Institute of Navigation

An Improved Acquisition Method for GNSS in High Dynamic Environments: Differential Acquisition Based on Compressed Sensing Theory

Due to the influence of bit sign and frequency error on integration peak, the Deterministic Compressed GNSS Acquisition Method (DCGAM) has poor detection performance in high dynamic environments. For fast acquisition in high dynamic environments, this paper has proposed an improved compressed GNSS acquisition method using adjacent part differential coherence. First, the adjacent part differential coherence process between the two neighbor milliseconds is used. This reduces the impact of bit sign and frequency error on the integration amplitude. Then, the decision variable is built when the differential signal goes through the compressed process. The detection probability, false alarm probability, and miss probability are derived to calculate the Mean Acquisition Time (MAT). Finally, the simulation results show that the proposed method has better detection probability and lower MAT than DCGAM under the same false alarm probability. Moreover, the experimental results yield these same results. Copyright © 2017 Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Autonomous Vehicle Dynamic Model-Based Navigation for Small UAVs

This paper presents a novel approach to autonomous navigation for small UAVs, with no extra sensor added to the conventional INS/GNSS setup. The proposed method significantly increases the accuracy and reliability of autonomous navigation, especially for small UAVs with low-cost IMUs. This improvement is of special interest in the case of GNSS outages, where inertial coasting drifts very quickly. In the proposed architecture, the VDM provides the estimate of position, velocity, and attitude, which is updated within a filter based on available observations, such as IMU data or when available, GNSS measurements. The filter is capable of estimating wind velocity and dynamic model parameters, in addition to navigation states and IMU sensor errors. Monte Carlo simulations reveal major improvements in navigation accuracy compared to conventional INS/GNSS systems during GNSS outages of 5 min. A discussion on the observability is also presented at the end. Copyright (C) 2016 Institute of Navigation.

Issue information - Proceedings of the Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Issue information - Proceedings of the Institute of Navigation

Methodology of Creation the Simulation Basin based on the Projected Canal through the Vistula Spit

Abstract The biggest problem in the process of implementation of the new sea areas project or aids to navigation systems is to check the assumptions without compromising security on real waters. Today, digital models are available for easy and inexpensive replacement of the research methods used so far. For this purpose the navigational and maneuvering simulators are perfect. Simulators as a research tools allow you to define a more realistic and accurate data for the study and evaluation sea areas. The purpose of the simulation is to identify and reduce the risk for seafarers during navigation on the waterways, canals and port areas. These include quantitative and qualitative assessment of the canals and fairways construction. The main requirement for a simulation system is to have a multi-task simulation software, which includes effective tools for repositioning and designing safe waterways and port infrastructure. The Institute of Navigation and Maritime Hydrography of the Polish Naval Academy since the eighties of the twentieth century is carried out projects in the field of navigational and hydrographic support of human activities at sea. This is possible thanks to the extensive set of simulation tools. Planning this tasks in a simulators software environment allow not only to design of virtual counterparts of real sea areas, but also to evaluate the quality of manufactured parts before their actual exposure to sea areas.

Quasi-tightly Coupled GNSS-INS Integration

Quasi-tightly coupled integration of Global Navigation Satellite System (GNSS) and inertial navigation system (INS) data is a method of loosely coupled integration that has the salient characteristic of continued aiding with fewer than four satellites that a tightly coupled integration typically exhibits. This method is intended for the integration of an existing GNSS navigation engine into a GNSS-INS closed-loop configuration with little or no modification of the GNSS navigation engine. The method of integration uses the range measurement model matrix typically used to compute dilutions of precision to identify the observable subspace in the time-space frame generated by the available satellites and project the loosely coupled INS–GNSS position measurement into this subspace. The GNSS navigation engine can therefore be any linear estimator. This paper describes the quasi-tightly coupled method applied to a single point positioning least squares adjustment and to a Kalman filter for GNSS position estimation. Copyright © 2015 Institute of Navigation

Automatic Identification and Calibration of Stochastic Parameters in Inertial Sensors

We present an algorithm for determining the nature of stochastic processes and their parameters based on the analysis of time series of inertial errors. The algorithm is suitable mainly (but not only) for situations where several stochastic processes are superposed. The proposed approach is based on a recently developed method called the Generalized Method of Wavelet Moments (GMWM), whose estimator was proven to be consistent and asymptotically normally distributed. This method delivers a global selection criterion based on the wavelet variance that can be used to determine the suitability of a candidate model (compared to other models) and apply it to low-cost inertial sensors. By allowing candidate model ranking, this approach enables us to construct an algorithm for automatic model identification and determination. The benefits of this methodology are highlighted by providing practical examples of model selection for two types of MEMS IMUs. Copyright (C) 2015 Institute of Navigation.

A Robust Shadow Matching Algorithm forGNSSPositioning

Commercial GNSS devices tend to perform poorly in urban canyon environments. The dense and tall buildings block the signals from many of the satellites. In this work, we present a particle filter algorithm for a Shadow Matching framework to face this problem. Given a 3D city map and given the satellites' signal properties, the algorithm calculates in real-time invalid regions inside the Region Of Interest (ROI). This approach reduces the ROI to a fraction of its original size. We present a general framework for a Shadow Matching positioning algorithm based on a modified particle filter. Using simulation experiments we have shown that the suggested method can improve the accuracy of existing GNSS devices in urban regions. Moreover, the proposed algorithm can be efficiently extended to 3D positioning in high sampling rate, inherently applicable for UAVs and Drones. Copyright © 2015 Institute of Navigation.

Design of a Passive Ranging System Using Existing Distance Measuring Equipment (DME) Signals & Transmitters

The US Federal Aviation Administration (FAA) is developing alternative navigation concepts to maintain operational capacity and efficiency even with the loss of Global Positioning System (GPS). One concept being studied for alternative position navigation and timing (APNT) is a ground based passive ranging system. This system has few capacity constraints and can provide other benefits. The APNT passive ranging system would use existing FAA terrestrial infrastructure, particularly distance measuring equipment (DME) ground beacons. APNT project team has developed a DME Pseudolite (PL) concept that enables a passive ranging signal on DME that is compatible with existing DME operations. It can provide additional benefits for APNT and non-APNT users with its data transmission. This paper introduces the DME PL concept and assesses the potential performance of the system. The paper focuses on signal structure design for best data capacity. It formulates a methodology and modeling for the developing the design. Copyright © 2015 Institute of Navigation.

An Investigation via Simulation and Measurements to Assess Vehicle Impact on Personal Privacy Device Antenna Radiation Patterns

This article presents a study of the radiation pattern of a personal privacy device (PPD) antenna on a fabricated vehicle and three commercial vehicles. Initially, electromagnetic modeling of the PPD antenna on the fabricated vehicle in three distinct antenna locations and two orientations per location was performed. Measurements were then conducted to gauge the accuracy of the simulations. Next, the same PPD antenna was placed in three locations and two orientations per location on three commercial vehicles to create 18 unique configurations. The maximum right hand circularly polarized gain vs. theta angle was analyzed. The results show that electromagnetic modeling of antennas mounted inside a vehicle differ significantly from measurements of the same scenario but acceptable agreement was achieved for exterior-mounted antennas on a vehicle. It also provides a vehicle efficiency value corresponding to the vehicle body frame's impact on a component-level PPD antenna radiation pattern over theta angles. Copyright © 2015 Institute of Navigation.

Improvement of INS-Aided GPS Tracking Performance under Strong Ionospheric Scintillation

Ionospheric anomalies are major error sources that affect the performance of the GPS (Global Positioning System). In particular, ionospheric scintillation may cause GPS satellite signal loss, and multiple losses can degrade the availability of positioning/navigation services such as GBAS (Ground-Based Augmentation Systems). In order to improve the tracking performance of GPS receivers under scintillation conditions, a tracking loop aided by INS (Inertial Navigation System) has been developed, and flight tests to evaluate it were conducted around the island of Ishigaki where ionosphere scintillation frequently occurs. Phase tracking performance evaluation was carried out off-line using a software-defined GPS receiver which processes stored IF (Intermediate Frequency) data. The use of INS enabled a longer integration time of GPS signals, which increased the signal-to-noise ratio (SNR). As a result, the INS-aided tracking loop achieved continuous phase tracking even under strong scintillation conditions. Copyright © 2015 Institute of Navigation.

Performance Analysis of L2 and L5 CNAV Broadcast Ephemeris for Orbit Calculation

Ephemeris error is a limiting factor in GPS position accuracy. The newly introduced GPS Civil Navigation (CNAV) broadcast message, an upgraded version of the legacy NAV message, is designed to provide users with more precise satellite orbit and timing parameters. A CNAV broadcast test was conducted in 2013 on the L2C and L5 bands. Since April 2014, pre-operational CNAV started to broadcast to civilian users. Baseband civil GPS signals on L1, L2, and L5 were recorded during the broadcast test and the pre-operational broadcast using wideband software radio front ends. The signals were acquired and tracked, with navigation messages decoded by the conventional Viterbi method and a computationally efficient matrix-based method. GPS ephemerides were extracted from the messages to compute satellite orbit solutions. This paper evaluates the orbit solution of both CNAV and Legacy NAV during the same time period to demonstrate the improvements in the CNAV ephemeris accuracy. Copyright © 2015 Institute of Navigation.

A Detailed Analysis of GPS Live-Sky Signals Without a Dish

This paper explores a premise that, with appropriate application of digital signal processing techniques, much of the detailed signal analysis typically associated with a dish can instead be done with a standard low-gain GNSS antenna. To do so, the signals of the recently launched GPS IIF satellites are examined, with particular attention on the L5 signal. Notably, using a high-quality non-directional GNSS antenna, we demonstrate observations of: (1) signal bandpass and dispersive characteristics, (2) chip shape, (3) eye and constellation diagrams, and (4) millisecond-level transient events. Such observations are enabled by use of the computationally efficient GNSS Complex Ambiguity Function (GCAF) technique. The methods used to process the GCAF data to produce these results are discussed in detail, with careful attention to the limitations of the techniques. Qualitative comparisons are made to similar dish-based measurements found in open literature. Copyright © 2014 Institute of Navigation.

Stability Criteria for GNSS Receiver Tracking Loops

This paper analyzes the stability criteria for closed loop tracking in a GNSS receiver using Bode analysis techniques. This defines the stable limits of predetection integration time (T) for a given loop filter design, including its order and noise bandwidth (Bn) in combination with all of the other components involved in the closed receiver tracking loop. The loop filter design used in this paper is based on a traditional analog design converted to digital using the bilinear transform. The shortcomings of this traditional design are briefly described, but the traditional design suffices for small T and ample phase margin. Clearly, a pilot channel in modern GNSS signals permits much longer T than allowed by the original GPS data channels, but the stability assurance must be considered in either case. The methodology applies to both data (Costas) and data-less (pilot) tracking loops. Additional insight is provided using the results of this analysis. Copyright © 2014 Institute of Navigation.