Two Identical GPS Units -- Different Accuracies? in GPS technology and devices Posted January 4, 2010 · Edited January 4, 2010 by Keo1 [to: StarBrand] I see. So you're saying that if the antenna is a half centimeter off from being accurately manufactured, or if the quartz-clock circuitry is off by a minute or more a week, then it won't be any less accurate. And that the converse will also never be true. Interesting. When temperatures get warmer though, I will benchmark my mailbox (at -20 to -30 F. I don't bother hiking all the way to my mailbox). This oddly accurate GPS unit has now got me curious to my assembly-line "lemon" and "gem" theory. I'm still curious if anyone else has reported a wide accuracy discrepancy between two well known and well used identical units. This problem exists in reviews and opinions of all other products manufactured. I fail to see how GPS units are magically exempt.