In-Between Mobile Maps and Media: Movement

2016 ◽  
Vol 18 (4) ◽  
pp. 320-335 ◽  
Author(s):  
Clancy Wilmott
Keyword(s):  
Global Positioning System ◽  
Positioning System ◽  
Mobile Mapping ◽  
Spatial Experience ◽  
Global Positioning ◽  
Reductive Process ◽  
Geocoded Data ◽  
The Relationship ◽  
Mobile Maps ◽  
Firsthand Experience

This article moves beyond the textuality of the map to focus on the way in which mobile mapping is constructed discursively, semiotically, and experientially. It centers on the autoethnographic and reflective experience of the researcher analyzing video and Global Positioning System (GPS) recordings of walking interviews, during which the interviewees conversed about, and engaged in, mobile mapping practices. This reductive process can be considered in light of its re-presentation to the researcher for analytical purposes—a ghostly abstraction of a past spatial experience. The article considers the manifold hauntings stirred in the process of abstraction and the creation of multiple layers of experience: that of the firsthand experience of the walking interview and that of the secondhand analysis of the video and geocoded data. The discrepancy between firsthand movement and secondhand analysis underscores questions about the relationship between mobile maps, representation, and movement and about those epistemologies and ontologies that haunt the interstices between individual records.

Accuracy of a Global Positioning System (GPS) for Weed Mapping

1997 ◽  
Vol 11 (4) ◽  
pp. 782-786 ◽  
Author(s):  
Theodore M. Webster ◽  
John Cardina
Keyword(s):  
Measurement Error ◽  
Global Positioning System ◽  
Patch Size ◽  
Positioning System ◽  
Weed Mapping ◽  
Global Positioning ◽  
The Relationship

Experiments were conducted to test the accuracy of a global positioning system (GPS) in measuring the area of simulated weed patches of varying size and to determine the accuracy in navigating back to particular points in a field. Circular areas of 5, 50, and 500 m2 were established and measured using point and polygon features of a GPS. The GPS estimations of the area of those patches had errors ranging from 7 to 45%, 6 to 15%, and 3 to 6%, respectively, when compared to actual measurements. As patch size increased, errors decreased. A curve describing the relationship between GPS error and patch size had an excellent fit (r2 = 0.92). The error remained the same in all measurements across all patch sizes, but composed a smaller percentage of large patches. The GPS had submeter accuracy in navigation to the correct quadrat 73% of the time, located the correct quadrat 27% of the time, and invariably navigated to within 1.58 m of the correct quadrat. The relationship between patch size and measurement error was applied to natural infestations of hemp dogbane.

EMERGENCY EVACUATION SIMULATION VISUALIZED BY MOBILE MAPPING SYSTEM

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Osamu Tsujihara ◽  
Hideyuki Ito ◽  
Terumasa Okamoto
Keyword(s):  
Global Positioning System ◽  
Emergency Evacuation ◽  
Positioning System ◽  
Mobile Mapping ◽  
Evacuation Simulation ◽  
Camera Angle ◽  
Mapping System ◽  
Global Positioning ◽  
Mobile Mapping System ◽  
Serial Images

Recently, studies on evacuation simulations have drawn up scenarios of evacuation under various situations. In this study, a system is proposed to show the results of evacuation simulations for disasters such as tsunamis and fires, with maps and serial images taken by MMS (Mobile Mapping System). The all-around view camera, angle meter, and GPS (Global Positioning System) antenna are mounted on a moving object, such as a car, in MMS. The serially-taken images can be related to GIS (Geographic Information System). Users can not only virtually experience the evacuation but also find the dangerous places by observing the 360-degree surrounding image.

scholarly journals Influence of Ephemeris Error on GPS Single Point Positioning Accuracy

2013 ◽  
Vol 48 (3) ◽  
pp. 125-139
Author(s):  
Ma Lihua ◽  
Meng Wang
Keyword(s):  
Global Positioning System ◽  
Simulation Analysis ◽  
Single Point ◽  
Line Of Sight ◽  
Positioning System ◽  
Gps Satellites ◽  
Time Period ◽  
Global Positioning ◽  
Orbital Position ◽  
The Relationship

Abstract The Global Positioning System (GPS) user makes use of the navigation message transmitted from GPS satellites to achieve its location. Because the receiver uses the satellite's location in position calculations, an ephemeris error, a difference between the expected and actual orbital position of a GPS satellite, reduces user accuracy. The influence extent is decided by the precision of broadcast ephemeris from the control station upload. Simulation analysis with the Yuma almanac show that maximum positioning error exists in the case where the ephemeris error is along the line-of-sight (LOS) direction. Meanwhile, the error is dependent on the relationship between the observer and spatial constellation at some time period.

scholarly journals A Novel Approach to Global Positioning System Accuracy Assessment, Verified on LiDAR Alignment of One Million Kilometers at a Continent Scale, as a Foundation for Autonomous Driving Safety Analysis

2021 ◽  
Author(s):  
Janusz Bedkowski ◽  
Hubert Nowak ◽  
Blazej Kubiak ◽  
Witold Studzinski ◽  
Maciej Janeczek ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Accuracy Assessment ◽  
Autonomous Driving ◽  
Safety Analysis ◽  
Driving Safety ◽  
Positioning System ◽  
Mobile Mapping ◽  
Data Alignment ◽  
Novel Approach ◽  
Global Positioning

This paper concerns a new methodology for accuracy assessment of global positioning system verified experimentally with LiDAR (Light Detection and Ranging) data alignment at continent scale for autonomous driving safety analysis. Accuracy of GPS (Global Positioning System) positioning of an autonomous driving vehicle within a lane on the road is one of the key safety considerations. Safety is addressed as a geometry of the problem, where the aim is to maintain knowledge that the vehicle (its bounding box) is within its lane. Accuracy of GPS positioning is checked by comparing it with mobile mapping tracks in the recorded high definition source. The aim of the comparison is to see if the GPS positioning remains accurate up to the dimensions of the lane where the vehicle is driving. For this reason, a new methodology is proposed. Methodology is composed of six elements: 1) Mobile mapping system minimal setup, 2) Global positioning data processing, 3) LiDAR data processing, 4) Alignment algorithm, 5) Accuracy assessment confirmation and 6) Autonomous driving safety analysis. The research challenge is to assess positioning accuracy of moving cars taking into account the constraints of the coverage of limited access highways in the United States of America. The available coverage limits the possibility of repeatable measurements and introduces an important challenge being the lack the ground truth data. State-of-the-art methods are not applicable for this particular application, therefore a novel approach is proposed. The method is to align all the available LiDAR car trajectories to confirm the GNSS+INS (Global Navigation Satellite System + Inertial Navigation System) accuracy. For this reason, the use of LiDAR metric measurements for data alignment implemented using SLAM (Simultaneous Localization and Mapping) was investigated, assuring no systematic drift by applying GNSS+INS constraints. SLAM implementation used state-of-the-art observation equations and the Weighted Non-Linear Least Square optimization technique that enables integration of the required constraints. The methodology was verified experimentally using arbitrarily chosen measurement instruments (NovAtel GNSS+INS, LiDAR Velodyne HDL32) mounted onto mobile mapping systems. The accuracy was assessed and confirmed by the alignment of 32785 trajectories with total length of 1,159,956.9~km and of total $186.4*10^{9}$~optimized parameters (six degrees of freedom of poses) that cover the United States region in the 2016--2019 period. It is demonstrated that the alignment improves the trajectories, thus final map is consistent. The proposed methodology extends the existing methods of global positioning system accuracy assessment focusing on realistic environmental and driving conditions. The impact of global positioning system accuracy on autonomous car safety is discussed. It is shown that 99\% of the assessed data satisfies the safety requirements (driving within lanes of 3.6~m) for Mid-Size (width 1.85~m, length 4.87~m) vehicle and 95\% for 6-Wheel Pickup (width 2.03--2.43~m, length 5.32--6.76~m). The conclusion is that this methodology has great potential for global positioning accuracy assessment at global scale for autonomous driving applications. LiDAR data alignment is introduced as a novel approach to GNSS+INS accuracy confirmation. Further research is needed to solve the identified challenges.

scholarly journals Roaming the Neighbourhood: Influences of Independent Mobility Parenting Practices and Parental Perceived Environment on Children’s Territorial Range

2019 ◽  
Vol 16 (17) ◽  
pp. 3129 ◽  
Author(s):  
Janae Vlaar ◽  
Mariana Brussoni ◽  
Ian Janssen ◽  
Louise C. Mâsse
Keyword(s):  
Global Positioning System ◽  
Parenting Practices ◽  
Positioning System ◽  
Independent Mobility ◽  
Neighbourhood Environment ◽  
Perceived Environment ◽  
Path Analyses ◽  
Global Positioning ◽  
The Relationship ◽  
Activity Diary

Children’s independent mobility (IM), their freedom to move about their neighbourhood without supervision by adults, has been in steady decline in recent decades. Previous research has linked perceptions of the environment with various measures of IM, but recently concerns have been raised regarding inconsistency in measuring IM. This study used various measures of IM and aimed to address how parental perceptions of the neighbourhood environment are associated with children’s territorial range (actual IM), as well as how this relationship is mediated by IM parenting practices (allowed IM). A sample of 105 child/parent dyads from Vancouver, Canada participated in this study. Children (age 10–13) wore a global positioning system (GPS) watch and an accelerometer and completed an activity diary for seven days to assess their territorial range. Parents completed a questionnaire that assessed perceptions of their neighbourhood environment and IM parenting practices—license for IM and roaming allowance. Path analyses were used to address the research aims. License for IM and roaming allowance mediated the relationship between perceived walking facilities, crime safety, and neighbourhood relations and children’s territorial range. Findings suggest that future interventions to increase children’s territorial range should focus primarily on attitude and behaviour change among parents to grant children more freedom.

Research on the Relationships Between Population Flow Based on Global Positioning System Location Information from Mobile Phone Networks and Influenza Infection Pathways Based on the Number of Anti-Influenza Drug Prescriptions at Pharmacies: A Pilot Study (Preprint)

2020 ◽  
Author(s):  
Qiushi Chen ◽  
Michiko Tsubaki ◽  
Yasuhiro Minami ◽  
Kazutoshi Fujibayashi ◽  
Tetsuro Yumoto ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Seasonal Influenza ◽  
Influenza Infection ◽  
Time Lag ◽  
Location Information ◽  
Positioning System ◽  
Location Data ◽  
Global Positioning ◽  
Infection Pathways ◽  
The Relationship

BACKGROUND Global seasonal influenza-associated respiratory excess mortality rates have been estimated at 4-8.8 per 100,000 individuals, and this is one of the major issues in public health. Designing efficient containment strategies for highly contagious diseases like influenza has been a subject of very considerable interest recently. Infectious disease epidemic tracking and forecasting have recently been attempted using data based on mobile phone global positioning system (GPS) location information. Tracking and forecasting local influenza spread may contribute to the control of influenza epidemics in an early stage. OBJECTIVE The objectives of this research were to analyze population flow using GPS location data based on the methods proposed by Iwata and Shimizu (2019), and to evaluate influenza infection pathways by determining the relationship between population flow and the number of drugs sold at pharmacies. METHODS Methods proposed by Iwata and Shimizu were applied for all 25 cells to estimate population flow. They proposed a neural collective graphical model (NCGM), which uses a neural network to incorporate the spatiotemporal dependency issue and reduce the estimated parameter. RESULTS The prescription peaks in cells 12 and 14, which had high population flows with cell 13, showed a high correlation with a delay of one to two days. The incubation period is one to four days (average two days) in seasonal influenza. One feature around cell 6 is the low number of prescriptions for anti-influenza drugs. The influenza infection may not have spread to cell 6 due to the low population flow from cells 12 and 13 with high prescriptions. Another feature is the observation of transmission of infection by a small number of influenza patients. In cells 5 and 6 where high population flows were suspected, there was a high cross-correlation value of prescription numbers with a seven-day time-lag. The time-lag is longer than the time-lag observed around cell 13 above. It was observed that not much population flows from cell 19 to the outside area on weekdays. This observation may have been due to geographical features and undeveloped transportation networks. The number of prescriptions for anti-influenza drugs in cell 19 remained low during the observation period. CONCLUSIONS This study conducted population flow estimation analyses during commuting times, based on region-specific GPS location data in four Prefectures in the Kansai region of Japan using methods proposed by Iwata and Shimizu. Furthermore, detailed comparative analyses of the relationship between estimated results of population flow and anti-influenza drug prescription data from pharmacies were conducted. It was found that influenza did not spread to areas with undeveloped traffic networks, and the peak number of drug prescriptions arrived with a time lag of several days in areas with a high amount of area-to-area movement due to commuting.

scholarly journals Ανάπτυξη διαδικασίας βαθμονόμησης συστήματος LiDAR

2012 ◽  
Author(s):  
Άννα Πόθου
Keyword(s):  
Global Positioning System ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Inertial Navigation ◽  
Light Detection And Ranging ◽  
Positioning System ◽  
Mobile Mapping ◽  
Mapping System ◽  
Global Positioning ◽  
Mobile Mapping System

Η παρούσα διατριβή εντάσσεται στο γενικότερο πεδίο της μετρητικής εκμετάλλευσης μη συμβατικών απεικονίσεων από ψηφιακά συστήματα, εστιάζοντας στα κινούμενα συστήματα χαρτογράφησης MMS (Mobile Mapping System) και ειδικότερα στα συστήματα LiDAR (Light Detection and Ranging).Το σύστημα LiDAR ανήκει στην κατηγορία των αερομεταφερόμενων συστημάτων απεικόνισης, αποτελεί συχνά βασικό τμήμα ενός MMS και θα μπορούσε να χαρακτηριστεί ως ένα σύνθετο σύστημα αφού περιλαμβάνει δέκτες GPS (Global Positioning System) και αδρανειακά συστήματα INS (Inertial Navigation System) για τις ανάγκες της πλοήγησης, ενώ για της χαρτογράφησης περιλαμβάνει απαραιτήτως μια διάταξη σάρωσης laser και πολύ συχνά μια ψηφιακή φωτομηχανή. Πρόσφατα, με την εξέλιξή τους τα συστήματα LiDAR έγιναν το κύριο εργαλείο για την απόκτηση δεδομένων επιφανείας (DTM, DSM κ.ά.) και αποτελούν πλέον εξελιγμένα συστήματα χαρτογράφησης. Ο επιτυχής συνδυασμός των δεδομένων που παράγουν τα διάφορα υποσυστήματα ενός MMS, αποτελεί παράγοντα καθοριστικής σημασίας για την σωστή λειτουργία του συστήματος. Η ακρίβεια του τελικού προϊόντος επηρεάζεται άμεσα από την ακρίβεια των επιμέρους δεκτών, την θέση και τον προσανατολισμό, που επιτυγχάνεται μέσω του συστήματος GPS/INS, τον συγχρονισμό τους, την βαθμονόμηση του συστήματος, τις ιδιότητες του δέκτη απεικόνισης (φωτομηχανή ή/και σύστημα LiDAR) και την επίδραση της γεωμετρίας τους. Παρόλα τα πλεονεκτήματα των σύγχρονων MMS, η πολυπλοκότητά τους παρουσιάζει απαιτήσεις κυρίως ως προς την ορθή βαθμονόμηση του συστήματος των δεκτών.Η ουσιαστική σημασία των διαδικασιών βαθμονόμησης για κάθε δέκτη ξεχωριστά, η χωρική σχέση μεταξύ του δέκτη INS και των δεκτών απεικόνισης καθώς και η απόκλιση της σχέσης αυτής με την πάροδο του χρόνου, το οποίο στην διεθνή βιβλιογραφία ονομάζεται boresight misalignent, δημιουργεί την ανάγκη περαιτέρω μελέτης. Ο στόχος της διατριβής αυτής είναι η δημιουργία μιας εύχρηστης μεθοδολογίας, με την οποία θα εκτιμώνται οι παράμετροι του boresight misalignment μεταξύ INS και LiDAR παρέχοντας τη δυνατότητα της εξάλειψης τυχόν χονδροειδών σφαλμάτων (outlier) των δεδομένων μέσω ποιοτικών ελέγχων (QA/QC). Για το σκοπό αυτό αναπτύχθηκε αλγόριθμος μετασχηματισμού μεταξύ δεδομένων αναφοράς τα οποία λαμβάνονται από φωτογραμμετρική απόδοση αεροφωτογραφιών και από σάρωση με χρήση LiDAR.Με στόχο την εν μέρει κάλυψη του αναμφισβήτητου κενού στην ελληνική αλλά μερικώς και στην διεθνή βιβλιογραφία, πραγματοποιείται αρχικά αναλυτική παρουσίαση των αρχών λειτουργίας των συστημάτων LiDAR. Περιγράφονται οι δέκτες πλοήγησης και απεικόνισης που συμπεριλαμβάνονται σε αυτά και αναλυτικά παρατίθεται η θεωρητική προσέγγιση του LiDAR/INS boresight misalignment και η έως σήμερα αντιμετώπιση του όλου ζητήματος. Προτείνεται μέθοδος βαθμονόμησης μεταξύ του LiDAR και του INS, μέσω του βέλτιστου συνδυασμού των δεδομένων LiDAR με εκείνα των αεροφωτογραφιών, η οποία συμβάλει στην βελτίωση της ακρίβειας σάρωσης επιφανείας μέσω LiDAR. Προσδιορίζονται κριτήρια επιλογής καταλλήλων θέσεων αναφοράς και μελετάται η αποτελεσματικότητά τους και η αξιοποίηση της χρήσης αστικών περιοχών για την εκτίμηση των παραμέτρων του LiDAR/INS boresight misalignment. Μελετάται η ελάχιστη πυκνότητα των θέσεων αναφοράς και η χωρική κατανομή τους, προκειμένου να εξαχθούν συμπεράσματα σε σχέση με τις καθοριστικής σημασίας, για το κόστος του έργου, επιλογές των συγκεκριμένων παραμέτρων που γίνεται κατά τον προγραμματισμό της πτήσης. Η θεωρητική προσέγγιση των ζητημάτων αυτών μετουσιώνεται σε πρακτικές εφαρμογές, με την βοήθεια κατάλληλων πραγματικών και προσομοιωμένων δεδομένων.

scholarly journals A Novel Approach to Global Positioning System Accuracy Assessment, Verified on LiDAR Alignment of One Million Kilometers at a Continent Scale, as a Foundation for Autonomous Driving Safety Analysis

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5691
Author(s):  
Janusz Bedkowski ◽  
Hubert Nowak ◽  
Blazej Kubiak ◽  
Witold Studzinski ◽  
Maciej Janeczek ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Accuracy Assessment ◽  
Autonomous Driving ◽  
Driving Safety ◽  
Positioning System ◽  
Mobile Mapping ◽  
Gps Positioning ◽  
Data Alignment ◽  
Novel Approach ◽  
Global Positioning

This paper concerns a new methodology for accuracy assessment of GPS (Global Positioning System) verified experimentally with LiDAR (Light Detection and Ranging) data alignment at continent scale for autonomous driving safety analysis. Accuracy of an autonomous driving vehicle positioning within a lane on the road is one of the key safety considerations and the main focus of this paper. The accuracy of GPS positioning is checked by comparing it with mobile mapping tracks in the recorded high-definition source. The aim of the comparison is to see if the GPS positioning remains accurate up to the dimensions of the lane where the vehicle is driving. The goal is to align all the available LiDAR car trajectories to confirm the of accuracy of GNSS+INS (Global Navigation Satellite System + Inertial Navigation System). For this reason, the use of LiDAR metric measurements for data alignment implemented using SLAM (Simultaneous Localization and Mapping) was investigated, assuring no systematic drift by applying GNSS+INS constraints. The methodology was verified experimentally using arbitrarily chosen measurement instruments (NovAtel GNSS+INS, Velodyne HDL32 LiDAR) mounted onto mobile mapping systems. The accuracy was assessed and confirmed by the alignment of 32,785 trajectories with a total length of 1,159,956.9 km and a total of 186.4 × 109 optimized parameters (six degrees of freedom of poses) that cover the United States region in the 2016–2019 period. The alignment improves the trajectories; thus the final map is consistent. The proposed methodology extends the existing methods of global positioning system accuracy assessment, focusing on realistic environmental and driving conditions. The impact of global positioning system accuracy on autonomous car safety is discussed. It is shown that 99% of the assessed data satisfy the safety requirements (driving within lanes of 3.6 m) for Mid-Size (width 1.85 m, length 4.87 m) vehicles and 95% for Six-Wheel Pickup (width 2.03–2.43 m, length 5.32–6.76 m). The conclusion is that this methodology has great potential for global positioning accuracy assessment at the global scale for autonomous driving applications. LiDAR data alignment is introduced as a novel approach to GNSS+INS accuracy confirmation. Further research is needed to solve the identified challenges.

Clarifying the Relationship between Quality of Global Positioning System Data and Precision of Positioning

2010 ◽  
Vol 136 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Ta-Kang Yeh ◽  
Yi-Jao Chen ◽  
Yi-Da Chung ◽  
Chung-Wei Feng ◽  
Guochang Xu
Keyword(s):  
Global Positioning System ◽  
Positioning System ◽  
Global Positioning ◽  
System Data ◽  
The Relationship
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