Improving goGPS:Java implementation,

web applications and add-ons

FOSS4G 2011 Osaka

GPS receivers for navigation(i.e. kinematic positioning)

15-30 cm 3-5 m 2-3 cm RTK

(L1+L2) DGPS / RTK (L1)

stand-alone

US $ 10000 - 30000 US $ 1000 - 2000 US $ 50 - 200

Double frequency geodetic receivers

Single frequency professional receivers

Single frequency low-cost (consumer-level) receivers

40 cm - 80 cm

goGPS single-frequency RTK

raw data!

Relative positioning (double differences)

GPS error budget:

- orbit error (ephemeris): negligible- satellite and receiver clock errors: negligible- ionosphere and troposphere effects: negligible if D<10 km

- signal degradation- hardware quality

DMaster receiver (known position)

Rover receiver

goGPS MATLAB

-  developed in MATLAB 7.6+

- GUIs available

-  Real-time and post-processing

-  works on both Windows and UNIX

goGPS Java

-  client/server architecture

- GUI not yet available

-  Real-time and post-processing

-  platform independent

-  faster than goGPS MATLAB

goGPS Java first official release (two days ago!)

http://www.gogps-project.org

Collaborative environment

http://sourceforge.net/projects/gogps/ http://code.google.com/p/gogps/

MATLAB Java

SVN Mercurial

goGPS international network (as of November 2011)

Polytechnic of Milan http://www.polimi.it

Osaka City University http://www.osaka-cu.ac.jp

OSGEO JP http://www.osgeo.jp

Cryms http://www.cryms.com

goGPS Applied Technology

http://www.apptec.co.jp

Galileian Plus http://www.galileianplus.it

FISIhttp://www.fisi.org

SBBhttp://www.sbb.ch

Tezukayama Gakuin University http://www.tezuka-gu.ac.jp/

gRED

Volunteers (open source)

Universidad de Jaén http://www.ujaen.es

(GNSS positioning services)

Post-processing

Real-time processing

Position known with few centimeters of error (RMS < 2 cm)

goGPS positioning using single frequency raw data:

- with TOPCON receivers → RMS 20 ~ 40 cm - with u-blox receiver → RMS 40 ~ 80 cm

TOPCON double frequency receivers

u-blox receiver

Accuracy tests with receivers mounted on a car driven at different speeds with good sky visibility condition.

Accuracy test (December 2010)

Kinematic positioning

Receiver: u-blox AEK-4T

goGPS solution - RTK (VRS) - Dynamical model (const vel.) - Observations weighted on SNR

u-blox solution - Stand-alone - Pedestrian dynamical model

2D translation: ~2m

Static positioning

u-blox+goGPS solution compared with static positioning by double frequency receiver:

~ 30 cm

Low-cost receivers supported by goGPS(as of November 2011)

u-blox 4T / 5T / 6T SkyTraq S1315F-RAWFastrax IT03

goGPS

Multi-receiver logging (since version 0.2.0beta)

RINEX 1

RINEX 2

RINEX 3

REC. 1

REC. 2

REC. 3

Multi-receiver test

Variable dynamic model (since version 0.2.0beta)

goGPS Kalman filter � dynamic model

static

constant velocity

constant acceleration

BEFORE v0.2.0beta � same dynamic model for each processing session

SINCE v0.2.0beta � the user can switch between different dynamic models during the survey

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Variable dynamic model

goGPS as a web service

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

Server providing goGPS as WPS (ZOO WPS engine)

Raw data loggers raw observations (e.g. RINEX files)

accurate positioning (e.g. KML file)

http://localhost/cgi-bin/zoo_loader.cgi?metapath=&ServiceProvider=zgoGPS&Service=WPS&Request=Execute&Version=1.0.0&Identifier=goGPS&DataInputs=Obs=rover.11o; Nav=rover.11n;mObs=master.11o

goGPS processing by grid computing (Oracle GridEngine)

Scalability test for goGPS Java server-side processing with concurrent requests (Yoshida, 2011)

goGPS for road mapping

Accurate path maps with low-cost GPS receivers, integrating the output into a web-GIS

goGPS tracks can be used for OpenStreetMap

Polyline simplification(goGPS MATLAB tool)

goGPS for surveying

Archeological surveying with a required accuracy of the order of ~50 cm

goGPS + + VRS (or closest station)RTK – L1 only

Swiss Federal Railways SMART project

raw data collector client-side

goGPS Java processing server-side

Swisstopo VRS

measuring geographic areas by means of low-cost RTK positioning

Server-side processing environment (courtesy of CRYMS Sagl)

eZe2 deviceBoard M2M/custom Cinterion TC65i uBlox 5T

Display Keyboard

Server unix based Tomcat 6.0 Eriadne Server goGPS service

Swisstopo

Master VRS

uBlox

Navigation Ephemeris

Swiss Federal Railways

SAP

Swiss Federal Railways SMART project

only logging raw data!

Swiss Federal Railways SMART project

Server-side monitor & control interface (courtesy of CRYMS Sagl)

Swiss Federal Railways SMART project

Precision test (courtesy of CRYMS Sagl)

Swiss Federal Railways SMART projectmeasuring geographic areas by means of low-cost RTK positioning

Testing the system performance �

(photos courtesy of CRYMS Sagl and Politecnico di Milano, Geomatics Laboratory)

Future developments

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

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

3) goGPS Java made available as an application (command line / GUI)

4) goGPS processing made publicly available as a web service