SparkFun RTK Express Plus Surveying Kit [SL2]The RTK Surveyor is a Bluetooth enabled multi band GNSS receiver based on the ESP32 from Espressif and the ZED F9P from u blox. Flip the switch and you'll have 300mm approximate accuracy out of the box and 18mm accuracy with RTCM corrections. This kit provides the L1 L2 antenna, adapters, interface cables, and chargers needed for general GNSS use. We generally recommend using your cellular phone as the radio backhaul for RTCM but you can also use your