SparkFun RTK Reference Station

The SparkFun RTK Reference Station, crafted in Boulder, Colorado, USA, is an ideal solution for high-precision geolocation, surveying, and time reference applications. This device simplifies the process of setting up a fixed location NTRIP server, therefore enabling RTK for rovers and serving as an NTP server for equipment synchronization and providing a highly accurate time base.

RTK, or Real Time Kinematics, involves a satellite positioning receiver that uses signals from the Global Navigation Satellite Systems (GNSS) in conjunction with a correction data stream to achieve enhanced positional accuracy. GNSS encompasses satellites from various systems including GPS (USA), GLONASS (Russia), Beidou (China), Galileo (Europe), and additional satellites like SBAS and QZSS. While these signals alone deliver approximately 30cm positional accuracy, an RTK receiver can use an additional Real Time Correction Message (RTCM) data stream to calculate the device's location with 1cm accuracy in real-time. The SparkFun Reference Station allows you to generate this correction data locally and share it via Ethernet with a few minutes of setup.

The Reference Station is powered by the ESP32-WROOM processor and u-blox ZED-F9P multi-band GNSS module and runs the same open-source firmware as other RTK products from SparkFun. It features 10/100 Mbps Ethernet connectivity and can be powered by Power-over-Ethernet (PoE). With a 4-bit SDIO interface for the microSD card and a high-speed SPI interface for the u-blox ZED-F9P GNSS module, this product offers significant improvement in read, write, and GNSS data transfer speed. It also includes an ATECC608A crypto co-processor for those interested in writing their own firmware or using the Reference Station for crypto mining/space weather station applications or to secure/authenticate your GNSS data.

The Reference Station can function as an affordable Network Time Protocol (NTP) time server for your Ethernet network. This allows the computers on your network to achieve much closer clock synchronization. The Reference Station supports DHCP by default but can be assigned a fixed IP address if desired. DNS, gateway, and subnet mask are all configurable.

The Reference Station is designed to be robust and lab friendly. All of the electronics (except the Qwiic OLED display) are mounted on a single circuit board. The device features ESP32 WiFi / Bluetooth antenna, GNSS antenna, and timing pulse output, all connected via robust SMA connectors. IO connections are made via a sturdy 3.5mm header with cage screw connections. The timing pulse SMA output is 3.3V by default but can be configured for 5V if needed and is good for 100kHz. The Reset and Mode switches are positioned for easy access. The device is housed in a custom extruded aluminum case with machined end panels and slotted flanges, making it easy to install in a weatherproof enclosure or in your server rack.

The Reference Station offers multiple power options and can be powered by any or all of the ESP32 USB connection, the u-blox ZED-F9P USB connection, a separate USB-C power port on the rear, Power-over-Ethernet (36V to 57V), or a 5V pin on the IO screw header. The GNSS SMA antenna connection provides 5V for the included active L1/L2 antenna. The Reference Station provides both short-circuit and open-circuit detection and protection for the antenna cable.

The Reference Station can function in multiple modes including as a GNSS Base Station with NTRIP where RTCM corrections are sent to a Caster over Ethernet, and as a Network Time Protocol (NTP) Server, providing high-accuracy timing data to other machines via an Ethernet network. It can also be used as a GNSS Positioning Receiver or GNSS Positioning with RTK, and as a GNSS NMEA/UBX TCP Client, sending NMEA and/or UBX navigation data to a remote server using TCP over Ethernet.

The kit includes the cased Reference Station, L1/L2/L5 GNSS Surveying Antenna, Reinforced RG58 TNC-SMA Cable (10m), SMA WiFi / Bluetooth Antenna, 32GB microSD Card (Class 10), USB-C Power Supply (5V 1A wall charger), USB-C Cable (A to C, 2m), and Ethernet Cable (CAT-6, 1m).