gogps: enhanced gps positioning as wps based …...gogps: enhanced gps positioning as wps based on...

goGPS: Enhanced GPS Positioning as goGPS: Enhanced GPS Positioning as WPS based on Open Source SoftwareWPS based on Open Source Software

Venkatesh Raghavan*, Eugenio Realini*, Daisuke Yoshida Venkatesh Raghavan*, Eugenio Realini*, Daisuke Yoshida and Mirko Reguzzoni**, and Mirko Reguzzoni**, * Osaka City University, Japan* Osaka City University, Japan** Geomatics Laboratory, Polytechnic of Milan, Como, Italy** Geomatics Laboratory, Polytechnic of Milan, Como, Italy

1919thth January 2010 January 2010Hyderabad, IndiaHyderabad, India

goGPS international projectgoGPS international project

Polytechnic of MilanPolytechnic of Milanhttp://www.polimi.ithttp://www.polimi.it

Osaka City UniversityOsaka City Universityhttp://www.osaka-cu.ac.jphttp://www.osaka-cu.ac.jp

OSGEO JPOSGEO JPhttp://www.osgeo.jphttp://www.osgeo.jp

Galileian PlusGalileian Plushttp://www.galileianplus.ithttp://www.galileianplus.it

CrymsCrymshttp://www.cryms.comhttp://www.cryms.com

goGPS

JSPSJSPShttp://www.jsps.go.jphttp://www.jsps.go.jp

Applied TechnologyApplied Technologyhttp://www.apptec.co.jphttp://www.apptec.co.jp

http://www.osaka-cu.ac.jp/

GPS positioning errorGPS positioning error

GPS error budget:

- ionosphere and troposphere delays- satellite and receiver clock errors

- signal degradation (obstructions, reflections)- issues related to hardware quality (mainly antenna)

GPS positioning: satellite-receiver distance measurementby knowing signal travel time

Relative positioning (RTK)Relative positioning (RTK)

GPS error budget:

- ionosphere and troposphere delays: negligible if D<10 km- satellite and receiver clock errors: erased


DMaster receiver(known position)

Rover receiver

Sky visibilitySky visibility

GPS error budget:



High cost High cost vsvs Low cost GPS Low cost GPS

GPS error budget:



High qualityHigh costBig size

Low qualityLow cost

Small size

goGPS low-cost RTKgoGPS low-cost RTK

GPS error budget:



RTK

observations weighing

Kalmanfiltering

Kalman filterKalman filter

It is the core of the software.

It updates the position of the receiver in real-time on the basis of:

• new measurements

• the state of the system at the previous epoch

To implement it, it is needed to define:

state variables

observation equations

dynamic model

goGPS nichegoGPS niche

15-30 cm 3-5 m2-3 cm

RTK DGPS Stand-alone

goGPSL1 RTK positioning

< 1 m

~ US $ 30000 ~ US $ 3000 ~ US $ 100

goGPS – ublox comparisongoGPS – ublox comparison

Receiver: u-blox AEK-4T

goGPS solution- RTK (VRS)- constant velocity dyn. model- observations weighted on SNR

u-blox solution- stand-alone- pedestrian dynamic model

2D shift: ~2m

Real-time processingReal-time processing

Internet

3G

Base station(s)

NTRIP(RTCM 3.1)

USB goGPS

Real-time positioning (1Hz)

Post-mission processingPost-mission processing

Internet

Base station(s)NTRIP(RTCM 3.1)

USB

goGPSRINEX

filesRINEX

files

Positioning

goGPS MATLABgoGPS MATLAB

- developed in MATLAB 7.x

- GUIs available

KML outputKML output

Latest developmentsLatest developments

1) stand-alone positioning (without master station)

2) static positioning

3) polyline simplification and map-matching algorithm

4) goGPS core ported to Java

5) goGPS processing as an OGC-standard web service by means of ZOO WPS framework

Stand-alone positioningStand-alone positioning

u-blox solution- stand-alone

goGPS solution- stand-alone

goGPS solution- VRS RTK

Static positioningStatic positioning

goGPS solution compared with static positioning by double frequency receiver:

~ 30 cm

Polyline simplificationPolyline simplification

Map-Matching

GPS Track Data Processing Workflow

FILTERING

MATCHINGOUTPUT

INPUT

Geographic Links between traces and road paths

Algorithm based on Hausdorff DistanceAlgorithm based on Frechet Distance, introducing road connectivity

Line Generalization

Douglas-Peucker algorithm with different distance measures

Primary Filters

PDOP,Fix Type,Satellite Number, ...

Advanced Filters

Velocity, Heading,Annular Velocity, ...

Vehicle GPS Track Logging Data

Porting goGPSPorting goGPS

Conversion from MATLAB to JAVA

- positioning func.- input/output- GPS formats- (...)

goGPS libs

goGPS core Kalman filter

GUIgoGPS GUI

MATLAB JAVA→

Java fast matrix computation library

goGPS Java vs MATLAB (1/3)goGPS Java vs MATLAB (1/3)

Server-grade PC Client-grade laptop

CPU Intel Core i7-8602.80 GHz (64 Bit)

Intel Pentium M1.30 GHz (32 Bit)

RAM 8 GB 1 GB

Operating System

Linux Slackware64 13.0

(Kernel 2.6.29.6)

Dual boot with:

Windows XP Professional SP3

Linux Slackware 12.2 (Kernel 2.6.27.7)

Test dataset: ~5 hour survey (17205 epochs) with a number of satellites ranging from 6 to 7


goGPS as a service (1/4)goGPS as a service (1/4)

goGPS will provide GPS data processing as a web processing service (WPS) to obtain accurate positioning from raw GPS observations

ZOO Server providinggoGPS as WPS

Rovers just acquiringraw data

raw observations(e.g. RINEX files)

accurate positioning(e.g. KML file)

http://www.zoo-project.org/

http://localhost/cgi-bin/zoo_loader.cgi?metapath=&ServiceProvider=zgoGPS&Service=WPS&Request=Execute&Version=1.0.0&Identifier=goGPS&DataInputs=Obs=perim2.08o;Nav=COMO1190.08n;mObs=COMO1190.08o



goGPS polyline simplification algorithm provided as a web processing service (WPS)

ZOO Server providingpolyline simplification

as WPS

Client devicegoGPS surveyed path

simplified polyline

Hardware prototypeHardware prototype

http://mbed.org/users/tosihisa/notebook/diy-gps-logger/

GPS raw data logging system

+ accelerometer+ gyroscope+ magnetic compass

Future developmentsFuture developments

1) Improvement of positioning algorithms, focusing on post-processing; additional receiver support; other satellite systems (Compass, Galileo, QZSS, GLONASS, EGNOS, MSAS)

2) Motion sensors integration (accelerometers, gyros, odometer, …) → hardware prototype

3) goGPS Java will be made available as open source software for end-user applications

4) goGPS + polyline simplification + map-matching will be made available as web services

ContactsContacts

goGPS website:

http://www.gogps-project.org

[email protected]

Thank you!

http://www.gogps-project.org/

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