Solar Freaks

Hi,i am new to this site .I am a student of el engineering and have to do a project.We have a Wattsun-az125 Solar panel (tracker)....it sends to the computer the voltages and currents it absorbs.I have to contruct a electric circuit to determine the angle (compared to a reference angle) and send it to the computer.Can anyone help me with this?do i have tp work with a sensor or something.Thanks in advance and please read through the lines my english is not very good