Glossary

Terms, acronyms and formats that recur in this guide, in alphabetical order.

AP *Access Point*. The WiFi network that MS2-net creates when it cannot find a known network, used for configuration from a browser (`http://192.168.4.1`). See `configurazione`. Bluetooth Short-range wireless interface of the ESP32, used to send the **NMEA** output to field apps on smartphones/tablets. Captive portal The "sign in to network" window that some phones open automatically when connecting to an access point. On MS2-net, if it gets in the way of configuration, open a **regular browser** at `http://192.168.4.1` instead. DHCP *Dynamic Host Configuration Protocol*. Automatic assignment of the IP address by the network. Alternative to a **static IP**. DOP *Dilution of Precision*. Index expressing how much the satellite **geometry** degrades or improves precision: low values = favourable geometry. ESP32 Microcontroller (ESP32-WROOM) that manages the interfaces, display, network and logic of the MS2-net; it integrates **WiFi** and **Bluetooth**. Ethernet Wired network. On MS2-net it is implemented with the **W5500** controller and is the distinguishing feature of the *net* variant. See `ethernet`. GNSS *Global Navigation Satellite System*. The family of satellite positioning systems: GPS, GLONASS, Galileo, BeiDou, QZSS and the SBAS augmentation systems. Static IP Network address set manually (together with gateway and DNS) that does not change over time: recommended for fixed bases. Alternative to **DHCP**. NMEA-0183 Text-based standard for navigation data output: sentences such as GGA (position), RMC (position/speed/time), GSA/GSV (satellites), VTG. NTRIP *Networked Transport of RTCM via Internet Protocol*. Protocol that distributes **RTCM** corrections over the network, from a *caster* to the receiver (rover) or from the receiver (base) to the caster. See `rtk-ntrip`. OTA *Over-The-Air*. Firmware update **over WiFi**, without a cable. See `ota`. PPK *Post-Processed Kinematic*. **After-the-fact** processing of raw data to obtain high-quality trajectories even without real-time corrections. RTCM Standard format (RTCM 3.x) for transmitting GNSS **differential corrections**, received by the rover and sent out by the base to enable **RTK**. RTK *Real-Time Kinematic*. Differential positioning technique that, using carrier-phase measurements and RTCM corrections, achieves **centimetre-level accuracy in real time**. The best state is *RTK fixed*. Survey-in Procedure by which a **base** determines its own position by averaging measurements over a given time/accuracy, before it starts transmitting corrections. See `rtk-ntrip`. W5500 **Ethernet** controller (WIZnet) connected to the ESP32 over SPI: it provides the wired network port of the MS2-net. Xmitting State shown on the display when MS2-net is working as a **base** and is **transmitting** RTCM corrections. ZED-F9P Multi-band GNSS receiver module from **u-blox**, the heart of the MS2-net: it provides the measurements and the centimetre-level RTK solution.