GNSS Flex pHAT with ZED-X20P & IM19 IMU

Jargon buster

Plain-language definitions for the technical terms used above.

B1I

A BeiDou satellite signal used for standard positioning. It matters because the receiver must support the signal bands used by a constellation to take advantage of those satellites.

B2a

A BeiDou satellite signal used by newer dual-band GNSS receivers. Support for B2a can improve accuracy and reliability when combined with other GNSS bands.

BDS

BeiDou, China’s satellite navigation system. Support for BDS gives the receiver access to more satellites, which can help maintain a better position fix in challenging locations.

breakout

A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.

E5a

A Galileo satellite signal band used for higher-performance positioning services. Support for E5a can help dual-band GNSS receivers improve accuracy and reduce errors from atmospheric delay.

EGNOS

Europe’s SBAS service for improving GNSS positioning accuracy and reliability. It is relevant if the receiver will be used in Europe or nearby supported areas without an RTK correction link.

Flash memory

Flash memory is non-volatile memory that retains stored data even when power is removed, and can be erased and rewritten in blocks. It lets data such as firmware, settings or saved records persist across power cycles.

GAGAN

India’s SBAS service for improving GNSS positioning. It matters for projects in its coverage region because it can improve standard GNSS accuracy when RTK is not being used.

Galileo

Europe’s satellite navigation system. Galileo support can improve satellite availability and accuracy, especially when combined with GPS and other constellations.

GNSS

GNSS stands for Global Navigation Satellite System, an umbrella term for satellite positioning networks such as GPS, GLONASS, Galileo and BeiDou. Receivers use these satellites to determine position, and high-precision units can output a steady stream of serial position data.

GPIO

General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.

GPS

The US satellite navigation system used by GNSS receivers to calculate position and time. Support for GPS is important because it is widely available and often used together with other constellations for more reliable positioning.

Gyroscope

A gyroscope measures rotation, such as how fast a board is turning around its X, Y, and Z axes. This matters for projects like gesture controls, balancing robots, and motion tracking where tilt or rotation changes need to be detected.

Headers

Rows of connector contacts on a fixed pitch (commonly 2.54 mm) used to link a board to a breadboard, jumper wires, or another board. They come as male pin headers and female socket headers; when a module ships with pre-soldered headers it can be used straight away, whereas bare pads require soldering the pins yourself.

I2C

I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.

IMU

An IMU (Inertial Measurement Unit) combines motion sensors, typically an accelerometer and gyroscope and sometimes a magnetometer, to measure movement and orientation. It can sense motion, tilt, vibration, rotation, and changes in direction, which is useful for tasks such as navigation, stabilisation, gesture detection, and asset tracking.

L1C/A

A GPS signal band used by many GNSS receivers for standard positioning. Support for this band helps determine which satellite signals the receiver can use and how well it can maintain a location fix.

L2C

A second GPS signal band used by dual-band GNSS receivers to improve precision and reduce errors caused by the atmosphere. It matters for RTK and high-accuracy applications because using two bands can produce faster and more reliable centimetre-level fixes.

L5

A modern GNSS signal band used by several satellite systems for more accurate and robust positioning. Dual-band receivers that include L5 can often perform better than single-band receivers, especially for RTK and areas with reflected signals.

LED

A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.

MSAS

Japan’s SBAS service for improving GNSS positioning. It is useful to know because SBAS benefits depend on whether your project is located in the service’s coverage area.

pHAT

A smaller add-on board format for Raspberry Pi, similar in idea to a HAT but usually not full-sized. It matters because pHAT compatibility can affect how neatly a board stacks or fits into a Raspberry Pi project.

PVT

Position, velocity and time data reported by a GNSS receiver. Knowing the PVT update rate helps you judge how often the board can provide basic navigation information to your project.

Qwiic

Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.

QZSS

Japan’s regional satellite navigation system designed to improve coverage around Japan and the Asia-Pacific region. QZSS support can improve satellite availability in supported regions when used alongside GPS.

RTK

Real-Time Kinematic positioning is a GNSS technique that uses correction data from a base station to greatly improve location accuracy. It matters if you need centimetre-level positioning for robotics, mapping, surveying, or tracking rather than ordinary metre-level GPS accuracy.

RX

RX means receive, usually showing data being received by the board. An RX indicator LED can help with troubleshooting USB or serial communication.

SBAS

Satellite-Based Augmentation System, a set of regional services that broadcast correction information for GNSS receivers. SBAS can improve ordinary GPS-style positioning, although it is not the same as centimetre-level RTK correction.

single-board computer

A complete computer built onto one circuit board, usually including the processor, memory, ports, and connectors. This matters because accessories like heatsinks must match the board’s layout and mounting holes to fit properly.

SMA

SMA is a small threaded coaxial (RF) connector widely used to attach antennas and other radio-frequency cables. A device with SMA antenna ports needs antennas or pigtails with matching SMA connectors, or a suitable adapter, to connect to them.

SPI

A fast serial communication bus often used for displays, memory cards, and sensors. It matters because SPI devices need specific pins for clock and data, plus a separate chip-select line for each device.

TX

TX means transmit, usually showing data being sent from the board. A TX indicator LED can help you see when the board is communicating or uploading code.

u.FL

u.FL is a tiny snap-on antenna connector often used on compact wireless boards. A board with u.FL usually needs an external antenna, which matters if the product will be inside an enclosure or needs better antenna placement.

UART

UART is a simple asynchronous serial interface that sends data over separate transmit and receive wires, usually labelled TX and RX, with both ends set to the same baud rate. It is a common way for microcontrollers and other serial devices to exchange data.

USB-C

USB-C is a small, reversible USB connector that can carry power, data and, on some devices, video over a single cable. The same connector can range from charging only to high-speed data, so the functions a given port actually supports vary.

WAAS

A North American SBAS service that provides correction data for GNSS receivers. It matters if you are using the product in a supported region and want better non-RTK positioning accuracy.