scholarly journals Validity of the AdMos, Advanced Sport Instruments, GNSS Sensor for Use in Alpine Skiing

2021 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Petter Andre Husevåg Jølstad ◽  
Robert Cortas Reid ◽  
Jon Glenn Omholt Gjevestad ◽  
Matthias Gilgien
Keyword(s):  
Accuracy Assessment ◽  
Satellite System ◽  
Low Noise ◽  
Alpine Skiing ◽  
Performance Parameters ◽  
Position Data ◽  
Turn Radius ◽  
Using Data ◽  
Global Navigation Satellite ◽  
Over Time

The AdMos receiver from Advanced Sport Instruments is a global navigation satellite system (GNSS) frequently used in alpine ski racing, with users from national and professional teams. Therefore, a validation was conducted for use of the AdMos in alpine skiing, using data from both recreational and competitive skiers. Athletes skied a total of 60 km in different measurement and skiing conditions, while carrying both an AdMos and a differential GNSS, which was used as the gold standard. From the GNSS position data, speed, acceleration, turn radius, trajectory incline and impulse were calculated as instantaneous and turn average measures for both GNSS systems and errors between the systems were calculated. The median and interquartile range (IQR) for the instantaneous errors were below 3.5 (3.5) m for horizontal plane position and below 7.0 (4.3) m for the 3D position. The median and IQR for instantaneous errors and turn average errors, respectively, were below 0.04 (0.24)/0.04 (0.16) m/s for speed, below 0.23 (1.06)/0.35 (0.63) m/s2 for acceleration, below 0.47 (5.65)/0.73 (5.3) m for turn radius, and below 0.043 (1.96)/0.42 (1.42) degrees for trajectory incline. The median and IQR for turn average impulse were 0.025 (0.099) BWs. The position error changed gradually and randomly over time, with low noise levels causing smooth trajectories of similar shape but spatially shifted from the true trajectory that allowed the position–time derivation of the performance parameters, and detection of turns with 3% median and 5% IQR error. The accuracy assessment revealed that (1) the error levels were comparable to other consumer-grade standalone GNSS units designed for sport; (2) the trajectories closely resembled the true trajectories but with a random shift that changed over time and had a low noise level; (3) there was a very low instantaneous speed error that may allow the detection of many performance aspects of skiing and other sports; and (4) there were larger instantaneous errors for the remaining performance parameters, which decreased substantially when averaged over a turn.

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.

Metode Deteksi ‘Potential Security Threats’ Pada ADS-B Data dengan Memonitor EM Emisi Radiasi pada Jaringan Ethernet

2019 ◽  
Vol 11 (1) ◽  
pp. 39-44
Author(s):  
Reza Septiawan ◽  
I Made Astawa ◽  
Arief Rufiyanto ◽  
Tahar Agastani
Keyword(s):  
Traffic Management ◽  
Air Traffic Management ◽  
Satellite System ◽  
Traffic Monitoring ◽  
Air Traffic ◽  
Security Threats ◽  
Signal Source ◽  
Position Data ◽  
Accurate Position ◽  
Global Navigation Satellite

Precision, Navigation, and Timing (PNT) system based on Global Navigation Satellite System (GNSS) becomes significant in the air traffic management, especially in the use of Automatic Dependent Surveillance Broadcast system (ADS-B) for air traffic monitoring. Therefore the integrity of GNSS is significant to provide a reliable data necessary for ADS-B. GNSS Interference due to intentional or unintentional surrounding signal source may decrease the integrity of GNSS signal and therefore may result in the in-accurate position data of ADS-B message. ADS-B message itself is also vulnerable from potential security threats in their network. This paper proposed a methodology to detect potential security threats of ADS-B network system for both GNSS signal and ADS-B data by measuring and monitoring the electromagnetic radiated emission from ethernet cable IPv4 Cat5.

scholarly journals Simulation of GNSS Availability in Urban Environments Using a Panoramic Image Dataset

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Sakpod Tongleamnak ◽  
Masahiko Nagai
Keyword(s):  
Urban Areas ◽  
Accuracy Assessment ◽  
Satellite System ◽  
Urban Environments ◽  
Panoramic Image ◽  
Image Processing Techniques ◽  
Gnss Positioning ◽  
Image Dataset ◽  
Global Navigation Satellite ◽  
Processing Techniques

Performance of Global Navigation Satellite System (GNSS) positioning in urban environments is hindered by poor satellite availability because there are many man-made and natural objects in urban environments that obstruct satellite signals. To evaluate the availability of GNSS in cities, this paper presents a software simulation of GNSS availability in urban areas using a panoramic image dataset from Google Street View. Photogrammetric image processing techniques are applied to reconstruct fisheye sky view images and detect signal obstacles. Two comparisons of the results from the simulation and real world observation in Bangkok and Tokyo are also presented and discussed for accuracy assessment.

scholarly journals SibNet — Siberian Global Navigation Satellite System Network: Current state

2018 ◽  
Vol 4 (4) ◽  
pp. 82-94 ◽  
Author(s):  
Юрий Ясюкевич ◽  
Yury Yasyukevich ◽  
Артем Веснин ◽  
Artem Vesnin ◽  
Наталья Перевалова ◽  
...  
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
General Information ◽  
Navigation Satellite ◽  
Main Research ◽  
Current State ◽  
Wide Range ◽  
Global Navigation ◽  
Using Data ◽  
Global Navigation Satellite

In 2011, ISTP SB RAS began to deploy a routinely operating network of receivers of global navigation satellite system signals. To date, eight permanent and one temporal sites in the Siberian region are operating on a regular basis. These nine sites are equipped with 12 receivers. We use nine multi-frequency multi-system receivers of Javad manufacturer, and three specialized receivers NovAtel GPStation-6 designed to measure ionospheric phase and amplitude scintillations. The deployed network allows a wide range of ionospheric studies as well as studies of the navigation system positioning quality under various heliogeophysical conditions. This article presents general information about the network, its technical characteristics, and current state, as well as the main research problems that can be solved using data from the network.

scholarly journals MOVING OBJECT CLASSIFICATION USING MULTILAYER LASER SCANNING WITH SPACE SUBDIVISION FRAMEWORK

2020 ◽  
Vol V-4-2020 ◽  
pp. 103-108
Author(s):  
M. Nakagawa ◽  
M. Taguchi
Keyword(s):  
Real Time ◽  
Urban Areas ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Object Classification ◽  
Point Clouds ◽  
Satellite System ◽  
Space Subdivision ◽  
Position Data ◽  
Global Navigation Satellite

Abstract. In this paper, we focus on the development of intelligent construction vehicles to improve the safety of workers in construction sites. Generally, global navigation satellite system positioning is utilized to obtain the position data of workers and construction vehicles. However, construction fields in urban areas have poor satellite positioning environments. Therefore, we have developed a 3D sensing unit mounted on a construction vehicle for worker position data acquisition. The unit mainly consists of a multilayer laser scanner. We propose a real-time object measurement, classification and tracking methodology with the multilayer laser scanner. We also propose a methodology to estimate and visualize object behaviors with a spatial model based on a space subdivision framework consisting of agents, activities, resources, and modifiers. We applied the space subdivision framework with a geofencing approach using real-time object classification and tracking results estimated from temporal point clouds. Our methodology was evaluated using temporal point clouds acquired from a construction vehicle in drilling works.

scholarly journals The Effect of Different Global Navigation Satellite System Methods on Positioning Accuracy in Elite Alpine Skiing

Sensors ◽  
2014 ◽  
Vol 14 (10) ◽  
pp. 18433-18453 ◽  
Author(s):  
Matthias Gilgien ◽  
Jörg Spörri ◽  
Philippe Limpach ◽  
Alain Geiger ◽  
Erich Müller
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Alpine Skiing ◽  
Positioning Accuracy ◽  
Global Navigation ◽  
Global Navigation Satellite

The Velocity and Energy Profiles of Elite Cross-Country Skiers Executing Downhill Turns With Different Radii

2014 ◽  
Vol 9 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Øyvind Sandbakk ◽  
Silvana Bucher Sandbakk ◽  
Matej Supej ◽  
Hans-Christer Holmberg
Keyword(s):  
Lower Energy ◽  
Satellite System ◽  
Energy Characteristics ◽  
Energy Profiles ◽  
Single Turn ◽  
Turn Radius ◽  
Cross Country Skiing ◽  
Cross Country ◽  
Global Navigation Satellite

This study examined the influence of turn radius on velocity and energy profiles when skidding and step turning during more and less effective downhill turns while cross-country skiing. Thirteen elite female cross-country skiers performed single turns with a 9- or 12-m radius using the skidding technique and a 12- or 15-m radius with step turning. Mechanical parameters were monitored using a real-time kinematic Global Navigation Satellite System and video analysis. Step turning was more effective during all phases of a turn, leading to higher velocities than skidding (P < .05). With both techniques, a greater radius was associated with higher velocity (P < .05), but the quality of turning, as assessed on the basis of energy characteristics, was the same. More effective skidding turns involved more pronounced deceleration early in the turn and maintenance of higher velocity thereafter, while more effective step turning involved lower energy dissipation during the latter half of the turn. In conclusion, the single-turn analysis employed here reveals differences in the various techniques chosen by elite cross-country skiers when executing downhill turns of varying radii and can be used to assess the quality of such turns.

scholarly journals An Extended Kalman Filter and Back Propagation Neural Network Algorithm Positioning Method Based on Anti-lock Brake Sensor and Global Navigation Satellite System Information

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2753 ◽  
Author(s):  
Jie Hu ◽  
Zhongli Wu ◽  
Xiongzhen Qin ◽  
Huangzheng Geng ◽  
Zhangbin Gao
Keyword(s):  
Back Propagation ◽  
Satellite System ◽  
Back Propagation Neural Network ◽  
Low Noise ◽  
Navigation Satellite ◽  
Vehicle Speed ◽  
T Box ◽  
Positioning Method ◽  
Heading Angle ◽  
Global Navigation Satellite

Telematics box (T-Box) chip-level Global Navigation Satellite System (GNSS) receiver modules usually suffer from GNSS information failure or noise in urban environments. In order to resolve this issue, this paper presents a real-time positioning method for Extended Kalman Filter (EKF) and Back Propagation Neural Network (BPNN) algorithms based on Antilock Brake System (ABS) sensor and GNSS information. Experiments were performed using an assembly in the vehicle with a T-Box. The T-Box firstly use automotive kinematical Pre-EKF to fuse the four wheel speed, yaw rate and steering wheel angle data from the ABS sensor to obtain a more accurate vehicle speed and heading angle velocity. In order to reduce the noise of the GNSS information, After-EKF fusion vehicle speed, heading angle velocity and GNSS data were used and low-noise positioning data were obtained. The heading angle speed error is extracted as target and part of low-noise positioning data were used as input for training a BPNN model. When the positioning is invalid, the well-trained BPNN corrected heading angle velocity output and vehicle speed add the synthesized relative displacement to the previous absolute position to realize a new position. With the data of high-precision real-time kinematic differential positioning equipment as the reference, the use of the dual EKF can reduce the noise range of GNSS information and concentrate good-positioning signals of the road within 5 m (i.e. the positioning status is valid). When the GNSS information was shielded (making the positioning status invalid), and the previous data was regarded as a training sample, it is found that the vehicle achieved 15 minutes position without GNSS information on the recycling line. The results indicated this new position method can reduce the vehicle positioning noise when GNSS information is valid and determine the position during long periods of invalid GNSS information.

scholarly journals Asymmetries in Ground Reaction Forces During Turns by Elite Slalom Alpine Skiers Are Not Related to Asymmetries in Muscular Strength

2021 ◽  
Vol 12 ◽  
Author(s):  
Jan Ogrin ◽  
Nejc Šarabon ◽  
Mads Kjær Madsen ◽  
Uwe Kersting ◽  
Hans-Christer Holmberg ◽  
...  
Keyword(s):  
Muscular Strength ◽  
Satellite System ◽  
The Body ◽  
Ground Reaction Forces ◽  
Alpine Skiing ◽  
Reaction Forces ◽  
Left And Right ◽  
Alpine Skiers ◽  
Global Navigation Satellite ◽  
Right Turns

The ground reaction forces (GRF) associated with competitive alpine skiing, which are relatively large, might be asymmetric during left and right turns due to asymmetries in the strength of the legs and torso and the present investigation was designed to evaluate this possibility. While skiing a symmetrical, 20-gate slalom course, the asymmetries of 9 elite alpine skiers were calculated on the basis of measurements provided by inertial motion units (IMU), a Global Navigation Satellite System and pressure insoles. In addition, specialized dynamometers were utilized to assess potential asymmetry in the strength of their legs and torso in the laboratory. In total, seven variables related to GRF were assessed on-snow and eight related to strength of the legs and torso in the laboratory. The asymmetries in these parameters between left and right turns on snow were expressed in terms of the symmetry (SI) and Jaccard indices (JI), while the asymmetries between the left and right sides of the body in the case of the laboratory measurements were expressed as the SIs. The three hypotheses to be tested were examined using multivariable regression models. Our findings resulted in rejection of all three hypotheses: The asymmetries in total GRF (H1), as well as in the GRF acting on the inside and outside legs (H2) and on the rear- and forefeet GRF (H3) during left and right turns were not associated with asymmetries in parameters related to muscular strength. Nevertheless, this group of elite slalom skiers exhibited significant asymmetry between their right and left legs with respect to MVC during ankle flexion (0.53 ± 0.06 versus 0.60 ± 0.07 Nm/kg, respectively) and hip extension (2.68 ± 0.39 versus 2.17 ± 0.26 Nm/kg), as well as with respect to the GRFs on the inside leg while skiing (66.8 ± 7.39 versus 76.0 ± 10.0 %BW). As indicated by the JI values, there were also large asymmetries related to GRF as measured by pressure insoles (range: 42.7–56.0%). In conclusion, inter-limb asymmetries in GRFs during elite alpine skiing are not related to corresponding asymmetries in muscular strength. Although our elite athletes exhibited relatively small inter-limb asymmetries in strength, their asymmetries in GRF on-snow were relatively large.

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