An Adaptive Weighting based on Modified DOP for Collaborative Indoor Positioning

Indoor localisation has always been a challenging problem due to poor Global Navigation Satellite System (GNSS) availability in such environments. While inertial measurement sensors have become popular solutions for indoor positioning, they suffer large drifts after initialisation. Collaborative positioning enhances positioning robustness by integrating multiple localisation information, especially relative ranging measurements between local users and transmitters. However, not all ranging measurements are useful throughout the whole positioning process and integrating too much data will increase the computation cost. To enable a more reliable positioning system, an adaptive collaborative positioning algorithm is proposed which selects units for the collaborative network and integrates ranging measurement to constrain inertial measurement errors. The algorithm selects the network adaptively from three perspectives: the network geometry, the network size and the accuracy level of the ranging measurements between the units. The collaborative relative constraint is then defined according to the selected network geometry and anticipated measurement quality. In the case of trials with real data, the positioning accuracy is improved by 60% by adjusting the range constraint adaptively according to the selected network situation, while also improving the system robustness.

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Design of a Multiband Global Navigation Satellite System Radio Frequency Interference Monitoring Front-End with Synchronized Secondary Sensors

Sensors ◽

10.3390/s18082594 ◽

2018 ◽

Vol 18 (8) ◽

pp. 2594

Author(s):

Aiden Morrison ◽

Nadezda Sokolova ◽

James Curran

Keyword(s):

Radio Frequency ◽

Global Navigation Satellite System ◽

Low Cost ◽

Satellite System ◽

Radio Frequency Interference ◽

Navigation Satellite ◽

Inertial Measurement ◽

Front End ◽

Global Navigation ◽

Global Navigation Satellite

This paper investigates the challenges of developing a multi-frequency radio frequency interference (RFI) monitoring and characterization system that is optimized for ease of deployment and operation as well as low per unit cost. To achieve this, we explore the design and development of a multiband global navigation satellite system (GNSS) front-end which is intrinsically capable of synchronizing side channel information from non-RF sensors, such as inertial measurement units and integrated power meters, to allow the simultaneous production of substantial amounts of sampled spectrum while also allowing low-cost, real-time monitoring and logging of detected RFI events. While the inertial measurement unit and barometer are not used in the RFI investigation discussed, the design features that provide for their precise synchronization with the RF sample stream are presented as design elements worth consideration. The designed system, referred to as Four Independent Tuners with Data-packing (FITWD), was utilized in a data collection campaign over multiple European and Scandinavian countries in support of the determination of the relative occurrence rates of L1/E1 and L5/E5a interference events and intensities where it proved itself a successful alternative to larger and more expensive commercial solutions. The dual conclusions reached were that it was possible to develop a compact low-cost, multi-channel radio frequency (RF) front-end that implicitly supported external data source synchronization, and that such monitoring systems or similar capabilities integrated within receivers are likely to be needed in the future due to the increasing occurrence rates of GNSS RFI events.

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Fused inertial measurement unit and real time kinematic-global navigation satellite system data assessment based on robotic total station information for in-field dynamic positioning

Precision agriculture '15 ◽

10.3920/978-90-8686-814-8_33 ◽

2015 ◽

pp. 275-282 ◽

Cited By ~ 2

Author(s):

D.S. Paraforos ◽

H.W. Griepentrog ◽

J. Geipel ◽

T. Stehle

Keyword(s):

Satellite System ◽

Measurement Unit ◽

Dynamic Positioning ◽

Navigation Satellite ◽

Inertial Measurement ◽

Data Assessment ◽

Field Dynamic ◽

System Data ◽

Global Navigation Satellite ◽

Robotic Total Station

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Rigorous Boresight Self-Calibration of Mobile and UAV LiDAR Scanning Systems by Strip Adjustment

Remote Sensing ◽

10.3390/rs11040442 ◽

2019 ◽

Vol 11 (4) ◽

pp. 442 ◽

Cited By ~ 10

Author(s):

Zhen Li ◽

Junxiang Tan ◽

Hua Liu

Keyword(s):

Inertial Measurement Unit ◽

Point Clouds ◽

Calibration Method ◽

Satellite System ◽

Measurement Unit ◽

Inertial Measurement ◽

Self Calibration ◽

Global Navigation Satellite ◽

Mean Square Errors ◽

Scanning Systems

Mobile LiDAR Scanning (MLS) systems and UAV LiDAR Scanning (ULS) systems equipped with precise Global Navigation Satellite System (GNSS)/Inertial Measurement Unit (IMU) positioning units and LiDAR sensors are used at an increasing rate for the acquisition of high density and high accuracy point clouds because of their safety and efficiency. Without careful calibration of the boresight angles of the MLS systems and ULS systems, the accuracy of data acquired would degrade severely. This paper proposes an automatic boresight self-calibration method for the MLS systems and ULS systems using acquired multi-strip point clouds. The boresight angles of MLS systems and ULS systems are expressed in the direct geo-referencing equation and corrected by minimizing the misalignments between points scanned from different directions and different strips. Two datasets scanned by MLS systems and two datasets scanned by ULS systems were used to verify the proposed boresight calibration method. The experimental results show that the root mean square errors (RMSE) of misalignments between point correspondences of the four datasets after boresight calibration are 2.1 cm, 3.4 cm, 5.4 cm, and 6.1 cm, respectively, which are reduced by 59.6%, 75.4%, 78.0%, and 94.8% compared with those before boresight calibration.

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A Method for Determination and Compensation of a Cant Influence in a Track Centerline Identification Using GNSS Methods and Inertial Measurement

Applied Sciences ◽

10.3390/app9204347 ◽

2019 ◽

Vol 9 (20) ◽

pp. 4347 ◽

Cited By ~ 6

Author(s):

Wladyslaw Koc ◽

Cezary Specht ◽

Jacek Szmaglinski ◽

Piotr Chrostowski

Keyword(s):

Local Coordinate System ◽

Target Position ◽

Satellite System ◽

Railway Track ◽

Inertial Measurement ◽

Track Geometry ◽

Method Of Calculation ◽

Mobile Satellite ◽

Global Navigation Satellite ◽

Geometric Layout

At present, the problem of rail routes reconstruction in a global reference system is increasingly important. This issue is called Absolute Track Geometry, and its essence is the determination of the axis of railway tracks in the form of Cartesian coordinates of a global or local coordinate system. To obtain such a representation of the track centerline, the measurement methods are developed in many countries mostly by the using global navigation satellite system (GNSS) techniques. The accuracy of this type of measurement in favorable conditions reaches one centimeter. However, some specific conditions cause the additional supporting measurements with a use of such instruments as tachymetry, odometers, or accelerometers to be needed. One of the common issues of track axis reconstruction is transforming the measured GNSS antenna coordinates to the target position, i.e., to the place between rails on the level of rail heads. The authors in their previous works described the developed methodology, while this article presents a method of determining the correction of horizontal coordinates for measurements in arc sections of the railway track. The presence of a cant causes the antenna’s center to move away from the track axis, and for this reason, the results must be corrected. This article presents a method of calculation of mentioned corrections for positions obtained from mobile satellite surveying with additional inertial measurement. The algorithm presented in the article and its implementation have been illustrated on an example of a complex geometric layout, where cant transitions exist without transition curves in horizontal plane. Such a layout is not preferable due to the additional accelerations and their changes. However, it allows the verification of the presented methods.

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Research on Absolute Calibration of GNSS Receiver Delay through Clock-Steering Characterization

Sensors ◽

10.3390/s20216063 ◽

2020 ◽

Vol 20 (21) ◽

pp. 6063

Author(s):

Feng Zhu ◽

Huijun Zhang ◽

Luxi Huang ◽

Xiaohui Li ◽

Ping Feng

Keyword(s):

Measurement Errors ◽

Periodic Variation ◽

Satellite System ◽

Absolute Calibration ◽

Universal Method ◽

Gnss Receiver ◽

Combined Uncertainty ◽

Zero Baseline ◽

Global Navigation Satellite ◽

Operation Status

The receiver delay has a significant impact on global navigation satellite system (GNSS) time measurement. This article comprehensively analyzes the difficulty, composition, principle, and calculation of GNSS receiver delay. A universal method, based on clock-steering characterization, is proposed to absolutely calibrate all types of receivers. We use a hardware simulator to design several experiments to test the performance of GNSS receiver delay for different receiver types, radio frequency (RF) signals, operation status and time-to-phase (TtP). At first, through the receivers of Novatel and Septentrio, the channel delay of Septentrio is 2 ns far lower than 65 ns for Novatel, and for the inter-frequency bias of GLONASS L1, Septentrio tends to increase within 10 ns compared with decreasing of Novatel within 5 ns. Secondly, a representative receiver of UniNav-BDS (BeiDou) is chosen to test the influence of Ttp which may be ignored by users. Under continuous operation, the receiver delay shows a monotone reduction of 10 ns as TtP increased by 10 ns. However, under on-off operation, the receiver delay represents periodic variation. Through a zero-baseline comparison, we verifies the relation between receiver delay and TtP. At last, the article analyzes instrument errors and measurement errors in the experiment, and the combined uncertainty of absolute calibration is calculated with 1.36 ns.

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A Vessel Positioning Algorithm Based on Satellite Automatic Identification System

Journal of Electrical and Computer Engineering ◽

10.1155/2017/8097187 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Shexiang Ma ◽

Jie Wang ◽

Xin Meng ◽

Junfeng Wang

Keyword(s):

Satellite System ◽

Automatic Identification ◽

Identification System ◽

Multiple Model ◽

Additional Measurement ◽

Automatic Identification System ◽

Interactive Multiple Model ◽

Global Navigation Satellite ◽

Positioning Algorithm ◽

Model Algorithm

Vessels can obtain high precision positioning by using the global navigation satellite system (GNSS), but when the ship borne GNSS receiver fails, the existence of an alternative positioning system is important for the navigation safety of vessel. In this paper, a localization method based on the signals transmitted by satellite-based automatic identification system (AIS) is proposed for vessel in GNSS-denied environments. In the proposed method, the positioning model is a modification on the basis of time difference and frequency difference of arrival measurements by introducing an additional measurement, and the measurement is obtained through the interactive multiple model algorithm. The performance of the proposed strategy is evaluated through simulations, and the results validate the feasibility and reliability of vessel localization based on satellite-based AIS.

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Train Wheel Condition Monitoring via Cepstral Analysis of Axle Box Accelerations

Applied Sciences ◽

10.3390/app11041432 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1432

Author(s):

Benjamin Baasch ◽

Judith Heusel ◽

Michael Roth ◽

Thorsten Neumann

Keyword(s):

Condition Monitoring ◽

Synthetic Data ◽

Real Data ◽

Satellite System ◽

Data Representation ◽

Operating Conditions ◽

Measurement Unit ◽

Railway Network ◽

Cepstral Analysis ◽

Global Navigation Satellite

Continuous wheel condition monitoring is indispensable for the early detection of wheel defects. In this paper, we provide an approach based on cepstral analysis of axle-box accelerations (ABA). It is applied to the data in the spatial domain, which is why we introduce a new data representation called navewumber domain. In this domain, the wheel circumference and hence the wear of the wheel can be monitored. Furthermore, the amplitudes of peaks in the navewumber domain indicate the severity of possible wheel defects. We demonstrate our approach on simple synthetic data and real data gathered with an on-board multi-sensor system. The speed information obtained from fusing global navigation satellite system (GNSS) and inertial measurement unit (IMU) data is used to transform the data from time to space. The data acquisition was performed with a measurement train under normal operating conditions in the mainline railway network of Austria. We can show that our approach provides robust features that can be used for on-board wheel condition monitoring. Therefore, it enables further advances in the field of condition based and predictive maintenance of railway wheels.

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Quality assessment of integrated water vapour measurements at St. Petersburg site, Russia: FTIR vs. MW and GPS techniques

10.5194/amt-2017-135 ◽

2017 ◽

Author(s):

Yana A. Virolainen ◽

Yury M. Timofeyev ◽

Vladimir S. Kostsov ◽

Dmitry V. Ionov ◽

Vladislav V. Kalinnikov ◽

...

Keyword(s):

Quality Assessment ◽

Water Vapour ◽

Measurement Errors ◽

Microwave Radiometer ◽

Satellite System ◽

Data Sets ◽

Atmospheric Conditions ◽

Assessment Protocol ◽

Integrated Water Vapour ◽

Global Navigation Satellite

Abstract. The cross-comparison of different techniques for atmospheric integrated water vapour (IWV) measurements is the essential part of their quality assessment protocol. We inter-compare the synchronised data sets of IWV values measured by Fourier-transform infrared spectrometer Bruker 125 HR (FTIR), microwave radiometer RPG-HATPRO (MW) and global navigation satellite system receiver Novatel ProPak-V3 (GPS) at St. Petersburg site between August 2014 and October 2016. Generally, all three techniques agree well with each other and therefore are suitable for monitoring IWV values at St. Petersburg site. We show that GPS and MW data quality depends on the atmospheric conditions; in dry atmosphere (IWV smaller than 6 mm), these techniques are less reliable at St. Petersburg site than the FTIR method. We evaluate the upper bound of statistical measurement errors for clear-sky conditions as 0.33 ± 0.03 mm (2.0 ± 0.3 %), 0.54 ± 0.03 mm (4.5 ± 0.3 %), and 0.76 ± 0.04 mm (6.3 ± 0.7 %) for FTIR, GPS and MW methods, respectively. We conclude that accurate spatial and temporal matching of different IWV measurements is necessary for achieving the better agreement between various methods for IWV monitoring.

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Resolving dynamic ground motions with high-rate GNSS and implications for data fusion in broadband seismology and Earthquake Early Warning

10.5194/egusphere-egu2020-13360 ◽

2020 ◽

Author(s):

Roland Hohensinn ◽

Nikolaj Dahmen ◽

John Clinton ◽

Alain Geiger ◽

Markus Rothacher

Keyword(s):

Data Fusion ◽

Real Time ◽

Early Warning ◽

Ground Motions ◽

Real Data ◽

Satellite System ◽

Earthquake Early Warning ◽

High Rate ◽

Velocity Waveform ◽

Global Navigation Satellite

In this paper we highlight the potential of geodetic high-precision and high-rate GNSS (Global Navigation Satellite System) sampling (1 to 100 Hz) for resolving seismic ground motions, of both the near and the far field of an earthquake. The analysis of the budget and characteristics of the error of high-rate GNSS displacement time series yields results, discussion, and conclusions on the sensitivity and waveform resolvability as well as on the derivation of a minimum detectable displacement (in the statistical sense).Based on these analyses, we show how GNSS can contribute to optimal broadband displacement and velocity waveform products by means of data fusion by combining measurements taken from co-located sensors &#8211; e.g. accelerometers or gyroscopes &#8211; in real-time, near real-time and postprocessing mode. Concerning the inclusion of GNSS for such an analysis, we also briefly explore the ability of GNSS to record signals from different earthquake magnitudes and epicentral distances. We show that high-rate GNSS is sensitive to displacements down to the level of a few millimeters, and even below &#8211; an example also comes from the detection of very small vibrations from 100 Hz GNSS data.We analyze measurements of synthetized signals obtained from experiments with a shake table, as well as from real data from strong earthquakes, namely the 6.5 Mw event of 2016 near the city of Norcia (Italy) and the 7.0 Mw Kumamoto earthquake of 2016 (Japan). Based on these data and our main findings, we finally discuss the role of GNSS in Earthquake Early Warning in terms of a fast hypocenter localization and reliable magnitude estimation.

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