The Open Source GPS Toolkit: A Review of the First Year

摘要

The open source GPS Toolkit (GPSTk) project, first presented at the ION-GNSS-2004, provides a software suite that supports general GNSS research, analysis and development. This paper will summarize improvements in the GPSTk since that first initial release. A growing community of users has adopted the GPSTk. Examples of how the GPSTk has benefited research, commercial, and military groups will be described. The goal of the GPSTk project is to free the research community from the burden of implementing standard satellite navigation algorithms. The project provides a software suite that consists of a set of applications built upon a central library. The GPSTk distribution is available for download at http://www.gpstk.org/. The software is organized into a core library, and a set of applications built upon the library. The GPSTk library provides functions that are common to many applications. The functions include: time conversion; matrix and statistical analyses; reading and writing of standard formats, such as RINEX and SP3; position determination using gradient and algebraic techniques; troposphere delay models; ionosphere delay models; and P-code generation. The library functionality can be accessed by users through custom-built software applications or through the applications distributed with the GPSTk. The GPSTk library and most of its applications are written in highly object oriented ANSI standard C++. Functionality in the library is accessed through functions associated with classes. Classes are an object oriented construct that binds data and functions into one module. One advantage of this approach is that the user can interchange equivalent classes. For example, the user can trivially switch from the use of broadcast to precise ephemerides. By providing these standard models in a production quality and modular form, the library empowers the user to concentrate on new applications rather than on base-level capabilities. The GPSTk software suite is available to the public under the Lesser GNU Public License, or LGPL. The LGPL grants the user a number of rights; notably, the ability to choose whether to modify and redistribute the source code.