CONTENT. 1. Overview of Locata positioning technology. 3. Motivation Locata in Croatia Analysis of the data gathered from the field

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1 Analysis of different LocataNet configurations on Locata positioning accuracy with emphasis on possibilities for displacements determination of constructions and implementation in construction monitoring systems PROPOSAL OF PHD THESIS RESEARCH SUBJECT PhD candidate:. Proposed supervisor: Assist. Prof. Rinaldo Paar, dipl. ing. geod. 2 nd International doctoral seminar on geodesy, geoinformatics and geospace 8 th 11 th May 2018, Dubrovnik, Croatia CONTENT 1. Overview of Locata positioning technology 2. Previous research of Locata positioning system Development: from prototype to fully functional system Using Locata for displacement measurements 3. Motivation Locata in Croatia Analysis of the data gathered from the field 4. Plan of PhD research Research hypotheses Next steps of research Scientific contribution of proposed research 5. Discussion and suggestions 15 May

2 1. LOCATA POSITIONING TECHNOLOGY GNSS Most frequently used positioning system Limitations: Obstruction of horizon Indoor and underground Height accuracy Pseudolites Ground based transmitters of GNSS like signals Limitations: Near/far Multipath Time synchronization 15 May LOCATA POSITIONING TECHNOLOGY Locata positioning technology Network of time synchronized pseudolites Goal of Locata positioning technology Real time Centimeter level accuracy To complement GNSS RTK Indoor and outdoor environments Components LocataLite transmitters Locata receiver (rover) LocataNet Network of at least 4 time synchronized LocataLites 15 May

3 2. DEVELOPMENT OF LOCATA TIME SYNCHRONIZATION TimeLoc Biggest technical achievement Each LocataLite at least two antennas (transmitting and receiving) No need for corrections from reference station LOCATA PROTOTYPE SYSTEM Existing GPS receiver chipset (both transmitter and receiver) Transmits a GPS L1 signal and C/A code pseudorange Restriction on transmitting on GPS signal frequencies Initialization: KPI only 15 May DEVELOPMENT OF LOCATA 15 May

4 2. DEVELOPMENT OF LOCATA Changing transmitting frequency ISM (Industrial, Scientific and Medical) band Simultaneous transmitting two signals on different frequencies Two separated transmitting antennas for each LocataLite Multipath mitigation On-the-fly ambiguity resolution TimeTenna New antenna design for Locata receiver Multipath challenging environment (indoor) V-Ray antenna 15 May LOCATA & DISPLACEMENT MEASUREMENTS Parsley Bay pedestrian bridge Locata prototype system Locata monitoring application Tumut Pond dam monitoring 15 May

5 2. LOCATA & DISPLACEMENT MEASUREMENTS 15 May LOCATA & DISPLACEMENT MEASUREMENTS 15 May

6 3. LOCATA IN CROATIA Project Wearable outdoor augmented reality system for enrichment of touristic content code-name Project Wonderland Locata main positioning system Positioning of the users enables embedding virtual objects in real world image Installed equipment: 6 LocataLite transmitters (with 3 x 6 itelite PAT24009 antennas) 2 Locata receivers (with 2 L-Com HG2403MGU-SM antennas) In December, 2015., Čakovec 15 May LOCATA IN CROATIA LL3 LL4 LL2 LL5 LL6 LL2 LL3 LL4 LL5 LL6 LL1 LL1 15 May May

7 3. LOCATA IN CROATIA Achieved cm-level precision Shortcomings: Deviations from true position Instability of LocataLite antennas Permanent installation of antennas New LocataNet establishment 15 May PREPARATION Upgrade of LocataLites Mobile waterproof enclosures 5 GHz Wireless Access Point for each LocataLite Wireless GSM modem Agreement between Faculty of Geodesy and Polytechnic of Međimurje Transfer of Locata equipment to Zagreb Aquired new equipment 18 itelite PAT2409 antennas 18 LMR radio cables (length 5 20 meters) 6 batteries (75 Ah - cca 20 running hours per charge) Antenna carriers and mounts installing antennas on tripods 15 May

8 4. RESEARCH GOAL AND HYPOTHESES Research goal: research abilities of Locata positioning system to determine displacements of constructions RESEARCH HYPOTHESES: 1. Using Locata can increase accuracy and reliability of determining displacements compared to using only GNSS methods 2. Optimization of LocataNet through all phases Increase accuracy in characteristic points and in direction of expected displacements 3. Relative positioning measurement noise reduction increase possibility to detect sub-cm level displacements 15 May PHD RESEARCH PLAN 1. Development of application for simulation of different LocataNet configurations, 2. Establishment of LocataNet within Faculty of Geodesy complex, 3. Analysis of measurement accuracy (different measurement processing), 4. Establishment LocataNet on wider (analysis of measurements), 5. Testing of Locata ability to detect simulated displacements 6. Determination of construction displacements 15 May

9 4. PHD RESEARCH PLAN [1/6] SIMULATION OF LOCATANET CONFIGURATION Calculate different accuracy and reliability indicators for any given LocataNet configuration: DOP values Elements of error ellipses Reliability of measurements (redundancy) Goal: 1. Increase accuracy and reliability of positioning solution at desired points/areas in network 2. Increase accuracy in the direction of expected displacement 15 May PHD RESEARCH PLAN [2/6] LOCATANET ON THE FACULTY OF GEODESY Test field: Small and narrow area (approx. 30 x 10 m) Surrounded by walls potentially high multipath WiFi interference Check validity of all components Testing in environment for which Locata is originally developed (GNSS challenging and INDOOR environments) Design to be transportable 15 May

10 4. PHD RESEARCH PLAN [3/6] MEASUREMENT ANALYSIS Purpose: Different test measurements to see the potential of Locata for displacement measurements Analysis of static positioning accuracy Antenna phase center offset and variations Different ambiguity resolutions (KPI and OTF) Relative positioning (double differenced phase measurements) Long term stability of positioning solution 15 May PHD RESEARCH PLAN [4/6] LOCATANET ON WIDER AREA Test field: Faculty of Geodesy calibration base area aprroximately 0.2 x 3 km Purpose: Influence of distances to LocataLites on measurement accuracy Analysis of relative and absolute positioning on wider area Poor vertical accuracy focus on determining horizontal displacements 15 May

11 4. PHD RESEARCH PLAN [5/6] DETECTING SIMULATED DISPLACEMENTS Measuring displacements with a priori known values Static displacements: Moving rover antenna for known value and in known direction Horizontal and vertical displacements From mm to cm level displacements Dynamic displacements: Simulated by multi-purpose universal testing machine intended for static and dynamic testing of mechanical properties of building materials and constructions Fast dynamic movements of known frequency and amplitude: 1 to 5 Hz From mm to cm level amplitude 15 May PHD RESEARCH PLAN [6/6] CONSTRUCTION DISPLACEMENTS Establishing LocataNet on construction (bridge or dam) Network configuration and measurement processing based on previous research Displacement measurements using classical geodetic methods Comparison of existing geodetic methods and Locata for displacement measurements 15 May

12 4. SCIENTIFIC CONTRIBUTION 1. Defining and analyzing accuracy of displacement determination using Locata and comparison with existing methods. 2. Defining techniques, procedures and recommendations to determine optimal LocataNet configuration for displacement measurements (with high accuracy and reliability) through LocataNet configuration simulations. 3. Development of different approaches of processing Locata measurements for increasing accuracy of positioning and displacement measurement. 15 May REFERENCES Barnes J., Rizos C., Wang J., Small D., Voigt G., Gambale N. (2003a). Locata: the positioning technology of the future? Barnes J., Rizos C., Wang J., Small D., Voigt G., Gambale N. (2003b). Locata: A New Positioning Technology for High Precision Indoor and Outdoor Positioning Barnes J., Rizos C., Wang J., Small D., Voigt G., Gambale N. (2003c). LocataNet: Intelligent time-synchronised pseudolite transceivers for cm-level stand-alone positioning Barnes J., Rizos C., Kanli M., Small D., Voigt G., Gambale N., Lamance J. (2004). Structural Deformation Monitoring using Locata Barnes J., Rizos C., Kanli M., Pahwa A., Small D., Voigt G., Gambale N., Lamance J. (2005). High accuracy positioning using Locata's next generation technology Barnes J., Rizos C., Kanli M., Pahwa A. (2006a). A Positioning Technology for Classically Difficult GNSS Environments from Locata Barnes J., Rizos C., Kanli M., Pahwa A. (2006b). Locata: A new positioning technology for classically difficult GNSS environments Barnes J., Lamance J., Lilly B., Rogers I., Nix M., Balls A. (2007a). An integrated Locata & Leica Geosystems positioning system for open-cut mining applications Barnes J., Rizos C., Pahwa A., Politi N., van Cranenbroeck J. (2007b). The Potential of Locata Technology for Structural Monitoring Applications 15 May

13 REFERENCES Bonenberg L. (2014). Closely-coupled integration of Locata and GPS for engineering applications Chen J. (2006). Pseudolite-augmented GPS survey technique for deformation monitoring: analysis and experimental study Choudhury M., Rizos C., Harvey B. (2009). A survey of techniques and algorithms in deformation monitoring applications and the use of the Locata technology for such applications Choudhury M., Rizos C. (2010). Slow structural deformation monitoring using Locata a trial at Tumut Pond Dam Choudhury M., Harvey B., Rizos C. (2011). A comparative analysis of displacement detection methods using Locata Choudhury M., Rizos C. (2011). Test results of Locata technology for deformation monitoring Trunzo A., Benshoof P., Amt J. (2011). The UHARS Non-GPS Based Positioning System Dai L., Wang J., Rizos C., Han S. (2001). Psudo-satellites applications in deformation monitorng Grgac I., Novaković G., Ilijaš R. (2016). First application of Locata positioning technology in Croatia Grgac I., Paar R., Marendić A., Jakopec I. (2017). The influence of different LocataNet configurations on positioning accuracy Meng X., Roberts, G.W., Dodson A.H., Cosser E., Barnes J. Rizos C. (2004). Impact of GPS satellite and pseudolite geometry on structural deformation monitoring: analytical and empirical studies 15 May REFERENCES Perrone P., Hoekstra G., Zuby D., Rader R. (2014). Locata Positioning Used for World's First Fullyautonomous Robotic Testing in Vehicle Collision Avoidance System Politi N., Li Y., Khan F., Choudhury M., Bertsch J., Cheong J., Dempster A., Rizos C. (2009). Locata: A New Technology for High Precision Positioning Rizos C., Barnes J., Small D., Voigt G., Gambale N. (2003). A New Pseudolite-Based Positioning Technology For High Precision Indoor and Outdoor Positioning Rizos C., Roberst G., Barnes J., Gambale N. (2010). Locata: A new high accuracy indoor positioning system Rizos C., Lilly B., Robertson C., Gambale N. (2011). Open Cut Mine Machinery Automation: Going Beyond GNNS With Locata Rizos C., Gambale N., Lilly B. (2013). Mine Machinery Automation Using Locata-Augmented GNSS Rizos C., Kealy A., Li B., Choudhury M., Choy S., Feng Y. (2014). Locata's VRay Antenna Technology Multipath Mitigation for Indoor Positioning URL 1: Locata Your Own GPS ( ) URL 2: projectwonderland.eu, Wearable Outdoor Augmented Reality System for Enrichment of Touristic Content ( ) 15 May

14 THANK YOU FOR YOUR ATTENTION 15 May