Virtual GPS is a GPS simulator software. You can use it to simulate a GPS receiver unit connected to your computer. It's ideal when you need GPS input, but you have no signal or you can use it to test your GPS applications. It supports various NMEA sentences, so it can be used with any GPS mapping software. It operates in two modes: simulator mode and file mode. In simulator mode the latitude and longitude coordinates are periodically incremented with a defined step. In file mode the GPS data is loaded from a text file which contains NMEA sentences.