Does the system need to be at the right hour in order to get a GPS fix

I am using an ARM device on which Debian is installed. A GPS chip is installed on the machine and I use it in my program. That being said, it seems extremely, long, or sometimes impossible to even get a fix. My device does not have a clock. Depending on the available sources, I may set the system data from somewhere else (IE if the user connected the device to the WIFI) I don't really know how timezones operate. My country has only one and it changes according to the season. My first question would be: - In Debian, is the system time relevant to get a GPS fix? - If so, what type of date must I set? My country uses GMT but it seems weird for a satellite to even care about that type of concept, I assume they use UTC - is this the case? Right now I'm off by one hour... I think. (09:05 UTC while my country's clock seems to be 10:05)