Folks who want to have pinpoint accuracy of up to 1cm in their GPS system might want to check out the Topcon GRS-1. This GPS network rover receiver comes in a highly portable and lightweight form factor with an affordable price point. Other features of the GRS-1 include an SD memory card slot, a 3.7″ touchscreen display, a 2 megapixel camera, an internal magnetic compass, Wi-Fi and Bluetooth connectivity and an optional GSM or CDMA internal modem – all crammed into a chassis that is able to shrug off a one meter drop.