README
------

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Contents:
---------

* Introduction
* Description: GPSTk C++ Library
* Description: GPSTk C++ Applications
* Description: GPSTk Python Bindings
* Installation
* Testing
* Help & Docs
* Contribution guidelines
* Contributor list
* Credits & Lineage
* License


Introduction:
-------------

The GPS Toolkit (GPSTk) is an open-source (LGPL) project sponsored by
the Space and Geophysics Laboratory (SGL), part of the Applied Research
Laboratories (ARL) at The University of Texas at Austin.

The primary goals of the GPSTk project are to:

* provide applications for use by the GNSS and satellite navigation community.
* provide a core library to facilitate the development of GNSS applications.


Description: GPSTk C++ Library:
-------------------------------

The GPSTk core library provides a number of models and algorithms found in GNSS
textbooks and classic papers, such as solving for the user position or estimating
atmospheric refraction. Common data formats such as RINEX are supported as well.

There are several categories of functions in the GPSTk library:

   1. GPS time. Conversion among time representations such as MJD, GPS week
      and seconds of week, and many others.

   2. Ephemeris calculations. Position and clock interpolation for both
      broadcast and precise ephemerides.

   3. Atmospheric delay models. Includes ionosphere and troposphere models.

   4. Position solution. Includes an implementation of a Receiver Autonomous
      Integrity Monitoring algorithm.

   5. Mathematics. Includes Matrix and Vector implementations, as well as
      interpolation and numerical integration.

   6. GNSS data structures. Data structures that contain observations mapped
      according to epochs, satellites, sources and types of observations.
      Appropriate processing classes are also provided, including a complete
      'Precise Point Positioning' (PPP) processing chain.

   7. Application framework. Includes processing command lines options,
      providing interactive help and working with file systems.

A more detailed description of the functionality provided by the GPSTk library
can be found in the Doxygen documentation on the GPSTk website.

    http://www.gpstk.org/bin/view/Documentation/WebHome

The GPSTk Core Library and its associated test programs can be built
independently of building the GPSTk Applications or Auxiliary Libraries.
The GPSTk Core Library source code contains no dependencies outside of the
GPSTk Core Library and Standard C++ and will build cleanly on all
supported platforms.


Description: GPSTk C++ Applications:
------------------------------------

The GPSTk libraries are the foundation for the GPSTk applications suite.
The applications support greater depth of functionality to support research
and development. The applications are almost entirely console based (i.e.,
without a graphical user interface). They can be grouped functionally into
the following categories:

   1. RINEX utilities - The RINEX utilities provide a set of applications
      that can be used to examine, manipulate, and plot RINEX observation
      files.

   2. Positioning - The positioning applications include two different
      applications that perform standard pseudorange-based positioning and
      two that implement differential phase-based solutions.

   3. Residual analysis - A residual analysis application computes two types
      of measurement residuals using a single receiver or two receivers in
      a zero baseline configuration.

   4. Ionospheric modeling - The ionospheric modeling applications utilize
      the two frequency TEC estimate from the RINEX utilities and compute
      a model of the ionosphere.

   5. Signal Tracking Simulation - These utilities simulate the tracking
      of GPS C/A and P-code.

   6. Basic transformations -  Conversions of time and coordinate systems.

   7. Observation data collection and conversion -  Translating receiver
      specific data formats to RINEX.

   8. File comparison and validation - Differing observations files against
     a truth source.

   9. Data editing - Simple editing like systematic removal of observations
      by satellite, type or time and more advanced editing like cycle slip
      detection and correction.

   10.Autonomous and relative positioning - Navigation and surveying
      applications.


The GPSTk applications are dependent on the GPSTk libraries.  However, the
GPSTk applications may also contain external dependencies.  Some applications
may not build or run successfully on all platforms.


Description: GPSTk Python Bindings:
-----------------------------------

The GPSTk python extension package provides access to the GPSTk C++ library
from within python. It is built using SWIG and CMake, and installed with a
standard setup.py script using the python distutils module.

For more details, see $GPSTK/python/bindings/swig/install_package/README.txt


Installation:
-------------

See the INSTALL.txt for details.

The most recent version of the GPSTk source code can be found here:

* http://www.gpstk.org
* https://github.com/SGL-UT/GPSTk
* http://sourceforge.net/projects/gpstk/

The tools used for the build and install frameworks are cross-platform.
These include CMake, SWIG, and python (distutils).

Automated build and install is supported on POSIX platforms with the
supplied Bash script called build.sh. For help on script usage,
run the script with the help flag:

    $ build.sh -h

For other platforms, such as Windows, please refer to comments and commands
in the same script, which document how we are using CMake, SWIG, and
distutils for various steps in the build and install process.

To build and install the C++ library and applications on POSIX platforms:

* automated: run build.sh.
* manual: see the contents of build.sh for command examples on how you might run cmake and make to build and install the library.

To build and install the python bindings, you have two options:

* automated: python bindings automatically build with the build.sh. Use -P for install.
* manual build: see build.sh for examples on calling cmake and swig
* manual install:


Testing:
--------

See the TESTING.txt for details.


Help & Docs:
------------

See the DOCUMENTATION.txt for details.

Additional documentation and resources can be found at http://www.gpstk.org/,
including:

* Source code and compiled binaries
* Coding examples
* Doxygen documentation
* System requirements and build instructions
* A users guide
* Publications
* Email lists
* Support question/answer
* Development process (including feature suggestions, bug tracking, schedule, testing, and developer documentation)
* Source code repository information
* GPSTk IRC channel
* Success stories

Credits & Lineage:
------------------

GPSTk is the by-product of GPS research conducted at ARL:UT since before the first
satellite launched in 1978; it is the combined effort of many software
engineers and scientists. In 2003 the research staff at ARL:UT decided to
open source much of their basic GPS processing software as the GPSTk.

The development history is documented by a series of related publications:

	http://www.gpstk.org/bin/view/Documentation/GPSTkPublications

See the AUTHORS.txt file for additional detail.

License
-------

The source code provided by the GPSTk is distributed under the GNU LGPL, Version 3.

* This license gives all users the right to use and redistribute the code.
* Users of the GPSTk are not required to open their source, according to the LGPL.
* This makes the GPSTk a practical choice for commercial projects.
* Full text copies of the GPL (COPYING.txt) and the LGPL (COPYING.LESSER.txt) are included with the GPSTk distribution package.

For more information about the GPL or LGP, please refer to the following:

* http://www.gnu.org/copyleft/lesser.html
* http://www.gnu.org/licenses/gpl-howto.html