Space & Time - Programming GPS and OpenStreetMap Applications with Java - page 45

For example, an application of our component might be attaching a GPS
smartphone to any object in the real world and retrieving its location by
calling it.
Before a programmer starts to code a component from scratch, it's gen-
erally a good idea to look for existing software and explore how it works
and how it might be modified. At SourceForge, there is a pretty good
match, written by Ulrich Walther, for the component we want to use as a
basis for our code:
sourceforge.net/projects/javagps or javagps.sourceforge.net
JavaGPS (V1.02) is a Java-only base library that enables ac-
cess to GPS devices from within any Java application. Pro-
vides Java API, NMEA0183 parser, record and playback GPS
log files, convert between earth dates and Gauss Krueger, GPS
management GUI with map.

The project given there gives a nice overview, preview, and review of global
positioning coding and does not require very high-level Java. You should
look at this library and then be able to create your own for the ROAF.

4.9 Requirements for a GPSunit

With a universal definition of space and time, all real objects and real-
object scenarios can be synchronized and positioned. The roaf.book.gps
package serves as a toolkit to manage geographical and metric coordinates.
We now create a GPSunit to keep track of time and space. This virtual
device can be added to any object to capture its motion. Every RO has a
built in GPS receiver or, in the simulated software world, a virtual GPSunit .
It is always a good idea to set up a requirements or feature list before
starting to code. For the JavaGPS project, the development steps might
include the following considerations:

1. A GPSunit determines its Position(lat,lon,elev) at any point in
time described by the java.util.Date class. Waypoints 7 and Routes
can be loaded to point the user to his destination.

2. A better GPSunit can provide live traces (or positions), record them,
and replay them to an application as if they were live.

3. Some GPS devices have a barometer (for elevation) and/or a compass
(for direction).

4. A nice feature is a \proximity alert" to inform the user that he is a
certain distance from a given position.

7 Waypoint is a GPS term for a Position(lat,lon) with a name.