If you have an excavator, a good idea is to use a GPS transmitter inside. It will help you to control employees and see where he is currently the lead excavations and work.
You will be able to make sure that your employees do not cheat and work without reservation. Dedicated systems often cost a lot and offer a lot of unnecessary options.
You can use the software CarTrack and mount your smartphone on the machine that will act as a transmitter and the site can be to follow the exact route of your excavator.