High Accuracy Positioning using Carrier-phases with the Barcelona, - PowerPoint PPT Presentation

gAGE research group of Astronomy and Geomatics High Accuracy Positioning using Carrier-phases with the Barcelona, Spain Open Source GPSTk Software Salazar D., Hernandez-Pajares M., Juan J.M. and Sanz J. gAGE/UPC, Barcelona, Spain 1 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Contents gAGE research group of Astronomy and Geomatics • GPSTk overview • Some current features Barcelona, Spain • GNSS Data Structures • Some processing examples • Conclusions and future work 2 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GPSTk overview gAGE research group of Astronomy and Geomatics • GPSTk is: – A library to write GNSS software – Includes example applications . Barcelona, Spain • GPSTk is Free Software (LGPL): – Both non-commercial and – commercial applications. 3 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GPSTk overview gAGE research group of Astronomy and Geomatics • Written in ISO-standard C++ (portable). • Operative System portability: Barcelona, Spain – Works in Windows, Linux, Mac OSX, AIX, Solaris, etc. • Hardware portability: – Big and (very) small systems, both 32 and 64 bits. 4 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GPSTk portability GUMSTIX gAGE research group of Astronomy and Geomatics Miniature computer Barcelona, Spain NOKIA Internet Tablets 5 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GPSTk overview gAGE research group of Astronomy and Geomatics • It was initiated at the Advanced Research Laboratories at Texas University (ARL:UT) • Now it has several official developers Barcelona, Spain around the world. • Project website: http://www.gpstk.org 6 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Some current features gAGE research group of Astronomy and Geomatics • Time conversions. • RINEX files reading/writing: – Observation Barcelona, Spain – Ephemeris – Meteorological • Ephemeris computation: – Broadcast – SP3. 7 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Some current features gAGE research group of Astronomy and Geomatics • Mathematical tools: Matrices, vectors, interpolation, numeric integration, LMS, W-LMS, Kalman filter, etc. Barcelona, Spain • Application development support: – Exceptions handling. – Command line framework. 8 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Some current features gAGE research group of Astronomy and Geomatics • Several tropospheric models: Saastamoinen, Goad-Goodman, New Brunswick, etc. • Classes for precise modeling: Phase centers, Barcelona, Spain Wind-up, gravitational delay, etc. • Tidal models: – Solid tides – Ocean loading – Pole tides 9 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GNSS Data Structures gAGE research group of Astronomy and Geomatics • GNSS Data Structures (GDS) were designed to help in GNSS data processing. Barcelona, Spain • They address GNSS data management problems. 10 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GNSS Data Structures gAGE research group of Astronomy and Geomatics • Almost all GNSS data may be identified (or indexed) by: – Source : Receiver logging data. Barcelona, Spain – Satellite : GPS, GALILEO, GLONASS... – Epoch : Time the data belongs to. – Type : C1, P1, L2, etc, and other types. Key point: Save Meta-Information: Save Meta-Information: Key point: Save 4 indexes 4 indexes to identify to identify Save each piece of data each piece of data 11 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GNSS Data Structures • Source : Implemented as class SourceID . gAGE research group of Astronomy and Geomatics • Satellite : Implemented as class SatID . – Several systems: GPS, Galileo, Glonass... Barcelona, Spain • Epoch : Implemented as class DayTime . • Type : Implemented as class TypeID . – Includes basic observations: C1, P1, etc. – Other “types”: Relativity, tropo, etc. – You can create new types as needed!!!. 12 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

gAGE research group of Astronomy and Geomatics Some conceptual GDS examples Barcelona, Spain 13 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Example: Rinex observation data for a given epoch gAGE research group of Astronomy and Geomatics Barcelona, Spain 14 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implicit Index gAGE research group of Astronomy and Geomatics Barcelona, Spain Real numerical values are down here... 15 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implicit Index Source gAGE research group of Astronomy and Geomatics Epoch Barcelona, Spain Sat Type Real numerical values are down here... 15 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Example: Pseudorange model equation gAGE research group of Astronomy and Geomatics Barcelona, Spain 16 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

gAGE research group of Astronomy and Geomatics Barcelona, Spain Epoch is implicit: Equation values are valid for a given epoch 17 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

GNSS Data Structures gAGE research group of Astronomy and Geomatics • Almost all GNSS data may be identified (or indexed) by: – Source : Receiver logging data. Barcelona, Spain – Satellite : GPS, GALILEO, GLONASS... – Epoch : Time the data belongs to. – Type : C1, P1, L2, etc, and other types. Key point: Save Meta-Information: Save Meta-Information: Key point: Save 4 indexes 4 indexes to identify to identify Save each piece of data each piece of data 18 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implementation • GDS have two parts: gAGE research group of Astronomy and Geomatics Header : Common information Barcelona, Spain “trunk” of tree “branches” of tree Body : Specific information 19 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implementation gAGE research group of Astronomy and Geomatics • GDS provide several methods to ease handling. For instance: Barcelona, Spain Keep only C1 observable in GDS: gpsData.keepOnlyTypeID(TypeID::C1) 20 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implementation gAGE research group of Astronomy and Geomatics • GDS provide several methods to ease handling. For instance: Barcelona, Spain Keep only C1 observable in GDS: gpsData.keepOnlyTypeID(TypeID::C1) GDS Method Type to keep 21 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implementation gAGE research group of Astronomy and Geomatics • GDS provide several methods to ease handling. For instance: Barcelona, Spain Access GDS in a matrix-like fashion: gpsData.body(TypeID::LI)(sat14) 22 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Implementation gAGE research group of Astronomy and Geomatics • GDS provide several methods to ease handling. For instance: Barcelona, Spain Access GDS in a matrix-like fashion: gpsData.body(TypeID::LI)(sat14) GDS “Branches” Type Satellite 22 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Processing paradigm gAGE research group of Astronomy and Geomatics • Operator “ >> ” is overloaded : Barcelona, Spain We redefine it in C++ to make data “ flow ” from one processing step to the next 23 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Processing paradigm gAGE research group of Astronomy and Geomatics Example: Declare object “rinexFile” to take data out of Rinex observation file: Barcelona, Spain RinexObsStream rinexFile("ebre0300.02o"); 24 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Processing paradigm gAGE research group of Astronomy and Geomatics Example: Declare object “rinexFile” to take data out of Rinex observation file: Barcelona, Spain RinexObsStream rinexFile("ebre0300.02o"); Class to handle Object name Rinex file name Rinex Obs files 24 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Processing paradigm gAGE research group of Astronomy and Geomatics Example: Declare object “gpsData”. This is a GDS : Barcelona, Spain gnssRinex gpsData; 25 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.

Processing paradigm gAGE research group of Astronomy and Geomatics Example: Declare object “gpsData”. This is a GDS : Barcelona, Spain gnssRinex gpsData; GDS Class Object name 25 4 th ESA Workshop on Satellite Navigation User Equipment Technologies. NAVITEC 2008.