More detail needed on CSV output from the i-gotU GT 600

Hi,
I need to know what the "Essential" data field in the CSV output provided by the i-gotU GT 600 means. The values are either a 1 or a 0 and 1 apparently means that the point has been "optimized". I believe it is the only fix quality parameter provided by the output and I want to know what data goes into determining if the point is optimized.

Ideally, I would like to get NMEA data from the unit to get better fix quality on the points. I was hoping to get HDOP, PDOP and number of satellites used to get the "fix". Does anyone know how to obtain this type of data from the unit?

Thanks! Rachel