The iTrek Z1 datalogger GPS with a solar panel is based on the MTK chipset produced beginning in Q1 2007. I brought this GPS data logger, along with three other GPS units, on an ethnoarchaeological research project in Peru in 2007 where we travelled with a traditional salt-bearing caravan for 14 days, and I gathered 9 days of data logging with the iTrek Z1. I conducted this test to evaluate the precision of the GPS in the southern hemiphere where there is no WAAS.