Introduction

SparkFun Quadband GNSS RTK Breakout - LG290P (Qwiic)
SKU: GPS-26620
The SparkFun Quadband GNSS RTK Breakout - LG290P (Qwiic) features the Quectel LG290P GNSS module. The board's dimensions, pin layout, and connectors are exactly the same as our vary popular SparkFun GPS-RTK-SMA Breakout - ZED-F9P (Qwiic); and can be used as a drop-in replacement. The board also accommodates users with a diverse choice of interfaces including UART, SPI¹, and I²C¹.

The LG290P module is a quad-band, multi-constellation, high-precision, RTK GNSS receiver. The module is capable of simultaneously receiving signals from the L1, L2, L5, and L6/E6 frequency bands of the GPS, GLONASS, Galileo, BDS, QZSS, and NavIC GNSS constellations. In addition, the module supports SBAS augmentation systems (WASS, EGNOS, BDSBAS, MSAS, GAGAN, and SDCM), PPP services² (BDS PPP-B2b, QZSS CLAS, MADOCA-PPP, and Galileo HAS), and RTK corrections for precision navigation with a fast convergence time and reliable performance.

The built-in NIC anti-jamming unit provides professional-grade interference signal detection and elimination algorithms, which effectively mitigate against multiple narrow-band interference sources and significantly improves the signal reception performance in complex electromagnetic environments. Additionally, the embedded algorithms ensure reliable positioning in complex scenarios such as urban environments and deep tree cover.

With its performance advantages of high-precision and low power consumption, this board is an ideal choice for high-precision navigation applications, such as intelligent robots, UAVs, precision agriculture, mining, surveying, and autonomous navigation.

Purchase from SparkFun

Features Under Development

I²C/SPI - Currently, only the UART interface is supported by the module.
PPP Services - Corrections for some of the PPP services have not been implemented.

Required Materials

To get started, users will need a few items. Some users may already have a few of these items, feel free to adjust accordingly.

Computer with an operating system (OS) that is compatible with all the software installation requirements
USB 3.1 Cable A to C - 3 Foot - Used to interface with the SparkFun Quadband GNSS RTK Breakout - LG290P (Qwiic) (1)
SparkFun Quadband GNSS RTK Breakout - LG290P (Qwiic)
GNSS Multi-Band L1/L2/L5 Surveying Antenna
- SMA Male to TNC Male Cable
- Antenna Mount

If your computer doesn't have a USB-A slot, then choose an appropriate cable or adapter.

GNSS Antennas & Accessories

For the best performance, we recommend users choose an active, multi-band GNSS antenna and utilize a low-loss cable. For additional options, please check out the GPS Antenna category of our product catalog.

GNSS AntennasCoaxial CablesMounting Hardware

Serial Transceivers, UART Adapters, and USB Cables

To configure the UART ports that are broken out on the board, users will need a UART adapter. Once configured, the UART ports can utilize one of our RF transceivers to send/receive RTCM messages.

TransceiversUART AdaptersUSB Cables

Headers and Wiring

To add headers or wiring, users will need soldering equipment and headers/wires.

New to soldering?

Check out our How to Solder: Through-Hole Soldering tutorial for a quick introduction!

How to Solder: Through-Hole Soldering

Qwiic Devices and Cables

Our Qwiic connect system is a simple solution for daisy chaining I²C devices without the hassle of soldering or checking wire connections. Check out other Qwiic devices from our catalog.

What is Qwiic?

The Qwiic connect system is a solderless, polarized connection system that allows users to seamlessly daisy chain I²C boards together. Play the video, to learn more about the Qwiic connect system or click on the banner above to learn more about Qwiic products.

QR code to instructional video

Features of the Qwiic System

No SolderingPolarized ConnectorDaisy Chain-able

no soldering - light theme no soldering - dark theme

Qwiic cables (4-pin JST) plug easily from development boards to sensors, shields, accessory boards and more, making easy work of setting up a new prototype.

polarized connector - light theme polarized connector - dark theme

There's no need to worry about accidentally swapping the SDA and SCL wires on your breadboard. The Qwiic connector is polarized so you know you’ll have it wired correctly every time.

The part numbers for the PCB connector is SM04B-SRSS (Datasheet) and the mating connector on the cables is SHR04V-S-B; or an equivalent 1mm pitch, 4-pin JST connection.

daisy chainable - light theme daisy chainable - dark theme

It’s time to leverage the power of the I²C bus! Most Qwiic boards will have two or more connectors on them, allowing multiple devices to be connected.

Jumper Modification

To modify the jumpers, users will need soldering equipment and/or a hobby knife.

New to jumper pads?

Check out our Jumper Pads and PCB Traces Tutorial for a quick introduction!

How to Work with Jumper Pads and PCB Traces

Hardware Overview

Design Files

The SparkFun LG290P Quadband GNSS RTK breakout board's dimensions, pin layout, and connectors are exactly the same as our vary popular SparkFun GPS-RTK-SMA Breakout - ZED-F9P (Qwiic); and can be used as a drop-in replacement. The board features three UART ports, which are accessible through the USB-C connector, BlueSMiRF (6-pin PTH) header , and 4-pin locking JST connector. Users can also interface with the board through the 24 PTH pins that are broken out around the edge of the board. For the GNSS antenna, an SMA antenna connector is provided on the edge of the board; additionally, there are also SMD pads for another *(RP-)*SMA connector to output a PPS signal. We also provide two 4-pin JST Qwiic connectors for future use, when the I^{2 feature becomes available for the GNSS module.}

Design Files
- Schematic
- KiCad Files
- STEP File
- Board Dimensions:
  - 1.70" x 1.70" (43.2mm x 43.2mm)
  - Four mounting holes:
    - 4-40 screw compatible

USB-C Connector

The USB connector is provided to power and communicate with the LG290P GNSS receiver. For most users, it will be the primary method for interfacing with the LG290P.

CH342 Dual UART Converter

The CH342 serial-to-USB converter allows users to interface with the UART1 port of the LG290P GNSS module through the USB-C connector. Although the CH342 provides a dual-channel UART interface, only a single channel is utilized to communicate with the LG290P GNSS module. To utilize the CH342, users may need to install a USB driver, which can be downloaded from the manufacturer website.

Once the USB driver is installed:

Two virtual COM ports will be emulated, which can be used as standard COM ports to access the receiver.
Users should select COM port with the lower enumeration or the one labeled as Channel A.

Tip - USB Drivers

Windows

Download Page for CH343SER.EXE
MacOS

Download Page for CH341SER_MAC.ZIP

Linux

A USB driver is not required for Linux based operating systems.

Power

The Quad-band GNSS RTK breakout board only requires 3.3V to power the board's primary components. The simplest method to power the board is through the USB-C connector. Alternatively, the board can also be powered through the other connectors and PTH pins.

Below, is a general summary of the power circuitry for the board:

5V - The voltage from the USB-C connector, usually 5V.
- Can be utilized as the primary power source for the entire board.
3V3 - 3.3V power rail, which powers the LG290P GNSS module, backup battery, and the power LED.
- Power can also be distributed to/from any of the 3V3 PTH pins or JST connectors (Qwiic or UART3).
  - For power that is supplied through these connections, the LG290P requires a supply voltage of 3.15–3.45V.
- A regulated 3.3V is supplied by the RT9080, when powered from the 5V PTH pin or USB connector
  - Input Voltage Range: 3.0 to 5.5V
  - The RT9080 LDO regulator can source up to 600mA.
3V3_EN - Controls the power output form the RT9080 voltage regulator.
- By default, the pin is pulled-up to 5V and to enable the RT9080 output voltage.
GND - The common ground or the 0V reference for the voltage supplies.

Info

For more details, users can reference the schematic and the datasheets of the individual components on the board.

Power Consumption

The power consumption of the LG290P GNSS module depends on the GNSS signals enabled and the positioning mode.

Current Consumption:
- Acquisition: 91mA (300.3mW)
- Tracking: 91mA (300.3mW)
- Backup Mode: 12μA (39.6mW)
Backup Battery

While charged, the backup battery allows the GNSS module to hot/warm start with valid ephemeris data (time and GNSS orbital trajectories) that was stored.

Time to First Fix:
- Cold Start: 28s
- Warm Start: 28s
- Hot Start: 1.7s

LG290P GNSS

The centerpiece of the Quad-band GNSS RTK breakout board, is the LG290P GNSS module from Quectel. The LG290P is a low-power, multi-band, multi-constellation GNSS receiver capable of delivering centimeter-level precision at high update rates. The built-in NIC anti-jamming unit provides professional-grade interference signal detection and elimination algorithms, which effectively mitigate against multiple narrow-band interference sources and significantly improves the signal reception performance in complex electromagnetic environments. With its performance advantages of high-precision and power consumption, this board is an ideal choice for high-precision navigation applications, such as intelligent robots, UAVs, precision agriculture, mining, surveying, and autonomous navigation.

General Features

Supply Voltage: 3.15–3.45V
Tracking Channels: 1040
Concurrent signal reception: 5 + QZSS
- L1, L2, L5, E6 frequency bands
Sensitivity:
- Acquisition: -146dBm
- Tracking: -160dBm
- Reacquisition: -155dBm
Antenna Power: External or Internal
GNSS Constellations and SBAS Systems:
- USA: GPS + WASS
- Russia: GLONASS + SDCM
- EU: Galileo + EGNOS
- China: BDS + BDSDAS
- Japan: QZSS + MSAS
- India: NavIC + GAGAN
Accuracy of 1PPS Signal: 5ns (RMS)
Update Rate:
- Default: 10Hz
- Max: 20Hz

Time to First Fix (without AGNSS):
- Cold Start: 28s
- Warm Start: 28s
- Hot Start: 1.7s
RTK Convergence Time: 5s
Dynamic Performance:
- Maximum Altitude: 10000m
- Maximum Velocity: 490m/s
- Maximum Acceleration: 4g
Built-in NIC anti-jamming unit
Interfaces
- UART (x3)
  - Baud Rate: 9600–3000000bps
    - Default: 460800bps
  - Protocol: NMEA 0183/RTCM 3.x
- SPI¹ (x1)
- I²C¹ (x1)
Operating temperature: -40°C to +85°C
Footprint: 12.2mm × 16mm × 2.6mm
Weight: ~0.9g

Supported Frequency Bands

The LG290P modules are multi-band, multi-constellation GNSS receivers. Below, is a chart illustrating the frequency bands utilized by all the global navigation satellite systems; along with a list of the frequency bands and GNSS systems supported by the LG290P GNSS module.

GNSS frequency bands — Frequency bands of the global navigation satellite systems. (Source: Tallysman)

Supported Frequency Bands:

GPS: L1 C/A, L1C², L5, L2C
GLONASS: L1, L2
Galileo: E1, E5a, E5b, E6
BDS: B1I, B1C, B2a, B2b, B2I, B3I
QZSS: L1 C/A, L1C², L5, L2C
NavIC: L5
SBAS: L1 C/A
L-band PPP³:
- PPP: B2b
- QZSS: L6
- Galileo HAS: E6

Supported GNSS Constellations:

GPS (USA)
GLONASS (Russia)
Galileo (EU)
BDS (China)
QZSS (Japan)
NavIC (India)

Supported SBAS Systems:

WASS (USA)
SDCM (Russia)
EGNOS (EU)
BDSBAS (China)
MSAS (Japan)
GAGAN (India)

Info

For a comparison of the frequency bands supported by the LG290P GNSS modules, refer to sections 1.2, 1.5, and 1.6 of the hardware design manual.

What are Frequency Bands?

A frequency band is a section of the electromagnetic spectrum, usually denoted by the range of its upper and lower limits. In the radio spectrum, these frequency bands are usually regulated by region, often through a government entity. This regulation prevents the interference of RF communication; and often includes major penalties for any interference with critical infrastructure systems and emergency services.

However, if the various GNSS constellations share similar frequency bands, then how do they avoid interfering with one another? Without going too far into detail, the image above helps illustrate some of the characteristics, specific to the frequency bands of each system. With these characteristics in mind, along with other factors, the chart can help users to visualize how multiple GNSS constellations might co-exist with each other.

For more information, users may find these articles of interest:

GNSS Accuracy

The accuracy of the position reported from the LG290P GNSS module, can be improved based upon the correction method being employed. Currently, RTK corrections provide the highest level of accuracy; however, users should be aware of certain limitations of the system:

RTK technique requires real-time correction data from a reference station or network of base stations.
- RTK corrections usually come from RTCM messages that are signal specific (i.e. an RTK network may only provide corrections for specific signals; only E5b and not E5a).
The range of the base stations will vary based upon the method used to transmit the correction data.
The reliability of RTK corrections are inherently reduced in multipath environments.

Correction Method	Horizontal	Vertical	Velocity
Standalone	0.7m ~2.3'	2.5m ~8.2'	3cm/s (0.108kph) ~1.2in/s (0.067mph)
RTK	0.8cm (+1ppm) ~0.3"	1.5cm (+1ppm) ~.6"

RTK Corrections

To understand how RTK works, users will need a more fundamental understanding of the signal error sources.

Peripherals and I/O Pins

The LG290P GNSS features several peripheral interfaces and I/O pins. Some of these are broken out as pins on the Quad-band GNSS RTK breakout board; whereas, others are broken out to their specific interface (i.e. USB connector, JST connector, etc.). Additionally, some of their connections are tied to other components on the board.

Interfaces:

UART (x3)
~~SPI¹~~
~~I²C¹~~
~~Event Trigger⁴~~
Timing Signal
RTK Signal
Module Reset

UARTsPPS OutputRTKReset

The LG290P GNSS has three UART ports, which can be operated and configured separately.

UART interface — The UART ports on the Quad-band GNSS RTK breakout board.

Default Configuration

By default, the UART ports are configured with the following settings:

Logic Level: 3.3V
Baudrate: 460800bps
Data Bits: 8
Parity: No
Stop Bits: 1
Flow Control: None
Protocols:
- NMEA 0183
- RTCM 3.x

Pin Connections

When connecting to the board's UART pins to another device, the pins should be connected based upon the flow of their data.

Board	RX	TX	GND
UART Device	TX	RX	GND

UART1UART2UART3

UART1 can only be accessed from the USB-C connector, through the CH342 serial-to-USB converter. For Windows and MacOS computers (1), a USB driver must be installed in order to communicate with the LG290P module through the CH342 converter. Once the USB driver is installed:

Two virtual COM ports are emulated, which can be used as standard COM ports to access the receiver.
Users should select COM port with the lower enumeration or listed as Channel A.

On Linux, the standard Linux CDC-ACM driver is suitable.

UART2 is available through the breakout PTH pins or the BlueSMiRF header pins. The pin layout of the BlueSMiRF header is pin compatible with many of our serial devices (i.e. UART adapters, serial data loggers, BlueSMiRF transceivers).

UART3 is available through the breakout PTH pins or the locking JST connector. The pin layout of the 4-pin locking JST connector is compatible with many of our serial radios and adapter cables.

UART Protocols

By default, the UART ports are configured to transmit and receive NMEA 0183 and/or RTCM 3.x messages. These messages are generally used for transmitting PNT data; and providing or receiving RTK corrections, respectively. Quectel also implements a system of proprietary messages (PQTM) for users to configure the LG290P, following the data format of the NMEA protocol. The expected structure of these proprietary messages is shown below:

NMEA data structure — The data structure of Quectel messages for the `NMEA` protocol.

NMEAPQTMRTCM

A full list of compatible NMEA 0183 v4.11 messages, is provided in section 2.2. Standard Messages of the GNSS Protocol Specification manual. This protocol is used for outputting GNSS data, as detailed by the National Marine Electronics Association organization.

List of Standard NMEA Messages

Message	Type Mode	Message Description
RMC	Output	Recommended Minimum Specific GNSS Data
GGA	Output	Global Positioning System Fix Data
GSV	Output	GNSS Satellites in View
GSA	Output	GNSS DOP and Active Satellites
VTG	Output	Course Over Ground & Ground Speed
GLL	Output	Geographic Position – Latitude/Longitude

A full list of PQTM messages (proprietary NMEA messages defined by Quectel) supported by LG290P, is provided in section 2.3. PQTM Messages of the GNSS Protocol Specification manual. This protocol is used to configure or read the settings for the LG290P GNSS module.

List of Proprietary Quectel Messages

Message	Type Mode	Message Description
PQTMVER	Output	Outputs the firmware version
PQTMCOLD	Input	Performs a cold start
PQTMWARM	Input	Performs a warm start
PQTMHOT	Input	Performs a hot start
PQTMSRR	Input	Performs a system reset and reboots the receiver
PQTMUNIQID	Output	Queries the module unique ID
PQTMSAVEPAR	Input	Saves the configurations into NVM
PQTMRESTOREPAR	Input	Restores the parameters configured by all commands to their default values
PQTMVERNO	Output	Queries the firmware version
PQTMCFGUART	Input/Output	Sets/gets the UART interface
PQTMCFGPPS	Input/Output	Sets/gets the PPS feature
PQTMCFGPROT	Input/Output	Sets/gets the input and output protocol for a specified port
PQTMCFGNMEADP	Input/Output	Sets/gets the decimal places of standard NMEA messages
PQTMEPE	Output	Outputs the estimated position error
PQTMCFGMSGRATE	Input/Output	Sets/gets the message output rate on the current interface
PQTMVEL	Output	Outputs the velocity information
PQTMCFGGEOFENCE	Input/Output	Sets/gets geofence feature
PQTMGEOFENCESTATUS	Output	Outputs the geofence status
PQTMGNSSSTART	Input	Starts GNSS engine
PQTMGNSSSTOP	Input	Stops GNSS engine
PQTMTXT	Output	Outputs short text messages
PQTMCFGSVIN	Input/Output	Sets/gets the Survey-in feature
PQTMSVINSTATUS	Output	Outputs the Survey-in status
PQTMPVT	Output	Outputs the PVT (GNSS only) result
PQTMCFGRCVRMODE	Input/Output	Sets/gets the receiver working mode
PQTMDEBUGON	Input	Enables debug log output
PQTMDEBUGOFF	Input	Disables debug log output
PQTMCFGFIXRATE	Input/Output	Sets/gets the fix interval
PQTMCFGRTK	Input/Output	Sets/gets the RTK mode
PQTMCFGCNST	Input/Output	Sets/gets the constellation configuration
PQTMDOP	Output	Outputs dilution of precision
PQTMPL	Output	Outputs protection level information
PQTMCFGODO	Input/Output	Sets/gets the odometer feature
PQTMRESETODO	Input	Resets the accumulated distance recorded by the odometer
PQTMODO	Output	Outputs the odometer information
PQTMCFGSIGNAL	Input/Output	Sets/gets GNSS signal mask
PQTMCFGSAT	Input/Output	Sets/gets GNSS satellite mask
PQTMCFGRSID	Input/Output	Sets/gets the reference station ID
PQTMCFGRTCM	Input/Output	Sets/gets RTCM

A full list of compatible RTCM v3 messages, is provided in section 3. RTCM Protocol of the GNSS Protocol Specification manual. This protocol is used for transferring GNSS raw measurement data, as detailed by the Radio Technical Commission for Maritime Services organization.

List of Supported RTCMv3 (MSM) Messages

Message	Type Mode	Message Description
1005	Input/Output	Stationary RTK Reference Station ARP
1006	Input/Output	Stationary RTK Reference Station ARP with height
1019	Input/Output	GPS Ephemerides
1020	Input/Output	GLONASS Ephemerides
1041	Input/Output	NavIC/IRNSS Ephemerides
1042	Input/Output	BDS Satellite Ephemeris Data
1044	Input/Output	QZSS Ephemerides
1046	Input/Output	Galileo I/NAV Satellite Ephemeris Data
1073	Input/Output	GPS MSM3
1074	Input/Output	GPS MSM4
1075	Input/Output	GPS MSM5
1076	Input/Output	GPS MSM6
1077	Input/Output	GPS MSM7
1083	Input/Output	GLONASS MSM3
1084	Input/Output	GLONASS MSM4
1085	Input/Output	GLONASS MSM5
1086	Input/Output	GLONASS MSM6
1087	Input/Output	GLONASS MSM7
1093	Input/Output	Galileo MSM3
1094	Input/Output	Galileo MSM4
1095	Input/Output	Galileo MSM5
1096	Input/Output	Galileo MSM6
1097	Input/Output	Galileo MSM7
1113	Input/Output	QZSS MSM3
1114	Input/Output	QZSS MSM4
1115	Input/Output	QZSS MSM5
1116	Input/Output	QZSS MSM6
1117	Input/Output	QZSS MSM7
1123	Input/Output	BDS MSM3
1124	Input/Output	BDS MSM4
1125	Input/Output	BDS MSM5
1126	Input/Output	BDS MSM6
1127	Input/Output	BDS MSM7
1133	Input/Output	NavIC/IRNSS MSM3
1134	Input/Output	NavIC/IRNSS MSM4
1135	Input/Output	NavIC/IRNSS MSM5
1136	Input/Output	NavIC/IRNSS MSM6
1137	Input/Output	NavIC/IRNSS MSM7

From the module, the PPS output signal is a 3.3V signal output that can be access through the SMA connector and/or the PPS PTH pin. The signal is also connected to the PPS LED, which can be used as a visual indicator for its operation.

I/O for PPS signal — The timing signal's outputs on the Tri-band GNSS RTK breakout board.

Jumpers

See the Jumpers section for more details.

There is a jumper attached to the PPS PTH pin. When cut, it disconnects the pin from the PPS signal.
There is a jumper attached to the PPS LED. For low power applications, the jumper can be cut to disable the PPS LED.

Use Case

Users could use this signal in conjunction with the event pins to synchronize two modules with each other.
Users could use this signal to create their own Stratum 0 source for the NTP on a primary time server.

The RTK PTH pin operates as both the RTK_STAT status indicator for the RTK positioning and ANT_ON power control for the external LNA or active antenna power. The pin is also connected to the RTK LED, which can be used as a visual indicator for its operation.

I/O for RTK signal — The RTK signal's outputs on the Tri-band GNSS RTK breakout board.

RTK_STATANT_ON

In this configuration, the pin is set to a high level at startup.

If the pin output is high, it indicates the module has entered the RTK fixed mode.
If the pin output is low, it indicates that the module exited the RTK fixed mode.
If the pin outputs an alternating pin level, it indicates that the module received the correct RTCM data and did not enter the RTK fixed mode.

In this configuration, the pin is used to control the external LNA or active antenna power supply.

When the pin is high, the antenna is powered.
When the pin is low, the antenna is not powered.

Jumpers

See the Jumpers section for more details.

There is a jumper attached to the RTK LED. For low power applications, the jumper can be cut to disable the RTK LED.

The RST pin can be used to reset the LG290P module if it enters an abnormal state. To reset the GNSS module, the pin must be low for more than 100ms.

Reset Pin — The `RST` pin on the Tri-band GNSS RTK breakout board.

SMA Connectors

While there are two SMD pads for SMA connectors, only the antenna's SMA connector is populated on the Quad-band GNSS RTK breakout board. The Antenna L1/2/5/6 connector is an input for the GNSS antenna. Whereas, the PPS SMD pad provides a output for the PPS timing signal.

Antenna Specifications

Passive antennas are not recommended for the LG290P GNSS module.
To mitigate the impact of out-of-band signals, utilize an active antenna whose SAW filter is placed in front of the LNA in the internal framework.
- DO NOT select and antenna with the LNA placed in the front.
There is no need to inject an external DC voltage into the SMA connector for the GNSS antenna. Power is already provided from the LG290P module for the LNA of an active antenna.

JST Connector

The Quad-band GNSS RTK breakout features a 4-pin JST GH connector, which is polarized and locking. Users can access the pins of the UART3 port, through the JST connector with our breadboard cable(1) or through the PTH pins. The pin layout of the JST connector is compatible with many of our serial radios and adapter cables.

Breadboard to JST-GHR-04V Cable - 4-Pin x 1.25mm Pitch
CAB-17240

The JST connector on the Quad-band GNSS RTK breakout board.

Pin Connections

When connecting the Quad-band GNSS RTK breakout board to other products, users need to be aware of the pin connections between the devices.

Pin Number	1 (Left Side)	2	3	4
Label	VCC	TX3	RX3	GND
Function	Voltage Output - Default: 3.3V - Selectable: 3.3V or 5V	`UART3` - Receive	`UART3` - Transmit	Ground

When connecting the Quad-band GNSS RTK breakout board to our radios, the pin connections should follow the table below. If the flow control is not enabled, the only the RX, TX, and GND pins are utilized.

Board	RX	TX	GND
Radio	TX	RX	GND

As documented in the LoRaSerial product manual, the pin connections between a host system (i.e. Quad-band GNSS RTK breakout board) and the LoRaSerial Kit radio is outlined in the image below.

Flow Control — The `COM` ports on the Quad-band GNSS RTK breakout board.

BlueSMiRF Header

The Quad-band GNSS RTK breakout features a 6-pin BlueSMiRF PTH header for UART2. The pin layout of which, is compatible with many of our serial devices (i.e. UART adapters, serial data loggers, BlueSMiRF transceivers).

Pin Connections

When connecting the Quad-band GNSS RTK breakout board to other products, users need to be aware of the pin connections between the devices.

Pin Number	1 (Left Side)	2	3	4	5	6
Label		TX2	RX2	3V3		GND
Function		`UART2` - Receive	`UART2` - Transmit	3.3V		Ground

Status LEDs

There are three status LEDs on the Quad-band GNSS RTK breakout board:

PWR - Power (Red)
- Turns on once 3.3V power is supplied to the board
PPS - Pulse-Per-Second (Yellow)
- Indicates when there is a pulse-per-second signal (see the PPS Output section)
RTK - RTK Mode (White)
- Indicates when an RTK fix has been established or when the correct RTCM data is being received (see the RTK section)

Jumpers

Never modified a jumper before?

Check out our Jumper Pads and PCB Traces tutorial for a quick introduction!

How to Work with Jumper Pads and PCB Traces

There are seven jumpers on the back of the board that can be used to easily modify the hardware connections on the board. From which, there are three jumpers that control power to the status LEDs on the board. By default, all the jumpers are connected, to power the status LEDs. For low power applications, users can cut the jumpers to disconnect power from each of the LEDs.

VSEL - This jumper can be modified to configure/disconnect the VCC pin of the 4-pin locking JST connector to/from 3V3 or 5V power.
BT_VCC - This jumper can be cut to disconnect the 3V3 BlueSMiRF header pin from the 3.3V output of the RT9080 LDO regulator.
PWR - This jumper can be cut to remove power from the red, power LED.
PPS - This jumper can be cut to remove power from the yellow LED, which is connected to the PPS signal.
RTK - This jumper can be cut to remove power from the white LED, indicating RTK fix or operation in RTK mode.
PPS-DC - This jumper can be cut to disconnect the pulse per second signal from the PTH pin.
SHLD - This jumper can be cut to disconnect the shielding of the USB-C connector from the GND plane of the board

Info

By default, PPS signal is connected to the PPS pin.

Hardware Assembly

USB Programming (`UART1`)

The USB connection can be utilized for serial communication and configuring the LG290P GNSS module. Users only need to connect their Quad-band GNSS RTK breakout board to a computer, using a USB-C cable.

Quad-band GNSS RTK breakout board USB connection — The Quad-band GNSS RTK breakout board with USB-C cable being attached.

Default Baud Rate

The default baud rate of the UART ports on the LG290P is 460800bps.

GNSS Antenna

In order to receive GNSS signals, users will need to connect a compatible antenna. For the best performance, we recommend users choose an active, multi-band GNSS antenna and utilize a low-loss cable.

Antenna Specifications

Passive antennas are not recommended for the LG290P GNSS module.
To mitigate the impact of out-of-band signals, utilize an active antenna whose SAW filter is placed in front of the LNA in the internal framework.
- DO NOT select and antenna with the LNA placed in the front.
There is no need to inject an external DC voltage into the SMA connector for the GNSS antenna. Power is already provided from the LG290P module for the LNA of an active antenna.

Quad-band GNSS RTK breakout board antenna connector — A GNSS antenna attached to the SMA connector on the Quad-band GNSS RTK breakout board.

JST Connector (`UART3`)

The JST connector on the Quad-band GNSS RTK board, breaks out the UART3 port of the LG290P GNSS module. In most circumstances, users will utilize the JST connector to interface with one of our radios to transmit or receive RTK correction data.

Device connected to the JST connector — The Telemetry Radio v3 connected to the Quad-band GNSS RTK breakout.

When connecting the Quad-band GNSS RTK breakout board to other products, users should be aware of the pin connections between the devices. The table below, details the pin connections of the locking JST connector on the Quad-band GNSS RTK breakout board.

Pin Number	1 (Left Side)	2	3	4
Label	VCC	TX3	RX3	GND
Function	Voltage Output - Default: 3.3V - 3.3V or 5V	`UART3` - Receive	`UART3` - Transmit	Ground

Default Baud Rate

The default baud rate of the UART ports on the LG290P is 460800bps.

Radio Transceivers

We have designed the locking JST connector to be plun-n-play with the following devices and cables. However, for the SiK Telemetry Radio v3, users should modify the VSEL jumper on the back of the board to enable a 5V output on the VCC pin. Below, is a table summarizing the pin connections of the radios.

Pin Number	1 (Left Side)	2	3	4	5	6 (Right)
Label	5V	RX - SiK RXI - LoRaSerial	TX - SiK TXO - LoRaSerial	CTS	RTS	GND
Function	Voltage Input - SiK: 5V - LoRaSerial: 3.3 to 5V	UART - Receive	UART - Transmit	Flow Control Clear-to-Send	Flow Control Ready-to-Send	Ground

Radio Pin Connections

As documented in the LoRaSerial product manual, the pin connections between a host system (i.e. Quad-band GNSS RTK breakout board) and the LoRaSerial radio is outlined in the image below.

UART w/ Flow Control — The pin connections between a radio and the Quad-band GNSS RTK breakout board.

However, the flow control pins (CTS and RTS) are not available on the Quad-band GNSS RTK breakout board. Therefore, when connecting either of the radios, the pin connections should follow the table below:

Board	RX	TX	GND
Radio	TX	RX	GND

Radio Transceivers and Cables

Default Baud Rate

The baud rate for these radios are configured by the SERIAL_SPEED parameter. The default configuration is SERIAL_SPEED: 57600bps.

Breakout Pins

The PTH pins on the Quad-band GNSS RTK board are broken out into 0.1"-spaced pins on the outer edges of the board.

New to soldering?

If you have never soldered before or need a quick refresher, check out our How to Solder: Through-Hole Soldering guide.

How to Solder: Through-Hole Soldering

Headers

When selecting headers, be sure you are aware of the functionality you require.

Hookup Wires

For a more permanent connection, users can solder wires directly to the board.

Soldering wires to the Quad-band GNSS RTK breakout board.

BlueSMiRF Header (`UART2`)

The BlueSMiRF header pins on the Quad-band GNSS RTK board, breaks out the UART2 port of the LG290P GNSS module. This pin layout is perfect for connecting a serial-to-UART adapter or a transceiver for serial data, such as the BlueSMiRF Bluetooth™ serial-link.

Male Header Attached — Soldering male header pins to the Quad-band GNSS RTK breakout board.

Female Header Attached — Soldering female header pins to the back of the Quad-band GNSS RTK breakout board.

Jumper Access

When soldering a header to the back of the board, be aware that you'll loose access to the jumper in that area.

BlueSMiRF transceiver - top — Female header covering the `BT-VCC` jumper.

Default Baud Rate

The default baud rate of the UART ports on the LG290P is 460800bps.

BlueSMiRFUART AdapterOpenLog

Default Baud Rate

The baud rate for the BlueSMiRF transceiver is configured by the SerialSpeed parameter. The default configuration is SerialSpeed: 115200bps.

Connecting a BlueSMiRF transceiver to a female header that was soldered to the Quad-band GNSS RTK breakout board. This will allow users to pair their board with a mobile device; and log PNT data on the mobile device and/or connect the LG290P to an NTRIP server for RTK corrections (through mobile device's cellular or WiFi connection).

BlueSMiRF transceiver - bottom — Female header pins soldered to the back of the board.

Connecting a UART adapter (Serial Basic) to a male header that was soldered to the Quad-band GNSS RTK breakout board. This will allow users to configure the LG290P, when the USB connection is unavailable.

Default Baud Rate

The baud rate for OpenLog needs to be configured in the config.txt file.

Connecting an OpenLog to the Quad-band GNSS RTK breakout board. This will allow users to automatically log PNT data from the LG290P.

Software Overview

CH342 USB Driver

The USB drivers for the CH342 USB-to-Serial converter can be downloaded from the manufacturer's website.

Windows

Download Page for CH343SER.EXE
MacOS

Download Page for CH341SER_MAC.ZIP

Linux

A USB driver is not required for Linux based operating systems.

GNSS Software

Tip

While it is not required, we highly recommend that users configure their LG290P GNSS module with the QGNSS software provided by Quectel. This is due to the unique data structure of the UART command messages, utilized to configure the LG290P module.

Windows Only

Currently, the QGNSS software is only available for Windows operating systems.

Windows, MacOS, or Linux

For users with computers that run on MacOS or Linux, we have found alternative software option for viewing the data from the NMEA messages. However, this GUI interface is currently limited to only receiving UART messages and cannot send messages to configure the LG290P module.

QGNSS Software

Windows Only

Currently, the QGNSS software is only available for Windows operating systems.

QGNSS is highly intuitive GNSS evaluation software that is easy to use, personalized, and compatible with leading Quectel technologies. The software allows users to define or apply GNSS product configurations for specific use cases. Saving, restoring, or sharing configurations between different products and users is easy. The software supports product evaluation with a choice of views to observe static and dynamic behavior of the connected a Quectel GNSS receiver.

Download the QGNSS Software (v2.0) from Quectel

System Requirements

Operating System: Windows

Connecting to the LG290P

In order to connect to the LG290P properly, users will need to specify the settings of the UART1 port.

Before users can connect to the Quad-band GNSS RTK breakout board, they will need to specify the connection settings in QGNSS. Once configured, users can select the OK button and QGNSS will automatically attempt to connect to the GNSS module.

Select the LG290P(03) from the drop-down menu to configure the Model of the GNSS module being connected.
Below, is a list of the default settings for UART ports of the LG290P. These settings should be selected in the Device Information menu, unless configured differently.
For the Port, select the port with the lowest enumeration of the CH342 or the port labeled with channel A from the drop-down menu.

UART Settings in QGNSS — Specify the settings for the UART port in QGNSS.

LG290P - Default Settings

The UART ports of the LG290P GNSS module will have the following default configuration:

Baudrate: 460800bps
Data Bits: 8
Parity: No
Stop Bits: 1
Flow Control: None

COM Ports — Available `COM`ports for the CH342. Select the lowest enumeration or the port labeled `A`.

Configure the LG290P

By default, the UART ports are configured to transmit and receive NMEA 0183 and/or RTCM 3.x messages. These messages are generally used for transmitting PNT data; and providing or receiving RTK corrections, respectively. Quectel also implements a system of proprietary messages (PQTM) for users to configure the LG290P, following the data format of the NMEA protocol.

Data Format - PQTM Messages

The expected structure of the data in the proprietary PQTM messages is shown below:

<Checksum>:

Checksum field follows the checksum delimiter character *.
Checksum is the 8-bit exclusive OR of all characters in the sentence, including , the field delimiter, between but not including the $ and the * delimiters.

<CR> & <LF>: Carriage return; followed by a new line

Depending on the terminal emulator, these may be options configured in the program settings.
Otherwise, usrs may need to add the \r and \n characters at the end of the message.

In the QGNSS software, users can click on the Advance button, at the bottom of the QConsole window, to configure the settings for the messages sent to the LG290P. Selecting NMEA and CRLF from the drop-down menu of the Checksum Type and Suffix options, will automatically calculate and append the <checksum> value, carriage return, and line follow to the end of the message entered in the Data Input field.

NMEA message setting — The settings for the messages transmitted from the QConsole.

Example - PQTMCFGUART Message

As an example, try utilizing the PQTMCFGUART PQTM message. Enter $PQTMCFGUART,R* into the Data Input* field of the QConsole. DOn't forget to select the NMEA and CRLF options from Advance settings menu. If entered and configured properly, the value 36 should pop up in the Checksum field of the QConsole; then, click on the button to send the message.

$PQTMCFGUART,R*

Once the message has been sent, keep a close watch of the messages in the console. It may help to click on the button to disable auto-scrolling, when trying to locate the message response. Additionally, the response may not appear right away, it could be appended to the end of the next data packet, as shown in the image below.

PQTM demo — Example of utilizing the Quectel PQTM messages in the QConsole.

PyGPSClient

Software Limitations

With this software, users will only be able to view the data from the NMEA messages and connect to an NTRIP caster. Users will not be able to configure the LG290P module with the built-in console.

As an alternative to QGNSS, for users with computers that run on MacOS or Linux, we recommend PyGPSClient as an option for viewing the data from the NMEA messages and connecting to an NTRIP caster. However, users should be aware that this GUI interface is currently limited to only receiving UART messages and cannot send messages to configure the LG290P module.

Resources

For additional information, users can refer to the following resources for the PyGPSClient software:

Installation

There are a variety of installation methods detailed in the GitHub repository's README.md file. However, we recommend utilizing the pip installation method.

Installation Commands

Depending on how Python is installed on the computer, one of the following commands should allow users to install the software.

```
python3 -m pip install pygpsclient
```
```
pip install pygpsclient
```

System Requirements

This installation method requires an internet connection. Additionally, users will also need administrative privileges (or root access sudo) for the installation.

Connecting to the LG290P

Before users can connect to the Quad-band GNSS RTK breakout board, they will need to specify the settings of the UART port in PyGPSClient. Once configured, users can select the button and PyGPSClient will automatically attempt to connect to the GNSS module.

Below, is a list of the default settings for UART ports of the LG290P. These settings should be selected in the configuration menu.
For the Serial Port, select the port with the lowest enumeration of the CH342 or the port labeled with channel A from the drop-down menu.

UART Settings in PyGPSClient — Specify the settings for the UART port in QGNSS.

LG290P - Default Settings

The UART ports of the LG290P GNSS module will have the following default configuration:

Baudrate: 460800bps
Data Bits: 8
Parity: No
Stop Bits: 1
Flow Control: None

Terminal Emulator

Another viable option for connecting to the Quad-band GNSS RTK breakout board, is to utilize a terminal emulation program. While reading the data sent from the LG290P is relatively trivial, users will need to be more selective when choosing an emulator to configure the LG290P module on the Quad-band GNSS RTK breakout board. This is due to the unique data structure of the proprietary messages that Quectel implements to configure the LG290P (see the Configure the LG290P section, above).

Arduino IDE

Tip

For first-time users, who have never programmed before and are looking to use the Arduino IDE, we recommend beginning with the SparkFun Inventor's Kit (SIK), which is designed to help users get started programming with the Arduino IDE.

Most users may already be familiar with the Arduino IDE and its use. However, for those of you who have never heard the name Arduino before, feel free to check out the Arduino website. To get started with using the Arduino IDE, check out our tutorials below:

SparkFun LG290P Quadband RTK GNSS Arduino Library

The SparkFun LG290P Quadband RTK GNSS Arduino Library can be installed from the library manager in the Arduino IDE by searching for:

SparkFun LG290P Quadband RTK GNSS Arduino Library

Click to enlarge — SparkFun LG290P Quadband RTK GNSS Arduino Library in the library manager of the Arduino IDE.

Manually Download the Arduino Library

For users who would like to manually download and install the library, the *.zip file can be accessed from the GitHub repository or downloaded by clicking the button below.

Download the Arduino Library

Resources

Product Resources

Additional Resources

🏭 Manufacturer's Resources

Quectel also provides great resources for the LG290P GNSS module:

Troubleshooting Tips

Need Help?

If you need technical assistance or more information on a product that is not working as you expected, we recommend heading over to the SparkFun Technical Assistance page for some initial troubleshooting.

SparkFun Technical Assistance Page

If you can't find what you need there, the SparkFun GNSS Forum is a great place to ask questions.

Account Registration Required

If this is your first visit to our forum, you'll need to create a Forum Account to post questions.

Feature Under Development

Currently, only the UART interface is supported by the module. Support for the I²C and SPI interfaces are still under development.

↩↩↩↩↩↩
Feature Under Development

Support for the L1C frequency band has not been implemented.

↩↩↩
Feature Under Development

Corrections for some of the PPP services have not been implemented.

↩
Feature Under Development

The event trigger has not been implemented.

↩

Introduction

Required Materials

Suggested Reading

Hardware Overview

Design Files

USB-C Connector

CH342 Dual UART Converter

Power

Power Consumption

Backup Battery

LG290P GNSS

Peripherals and I/O Pins

UART Protocols

SMA Connectors

JST Connector

Pin Connections

BlueSMiRF Header

Pin Connections

Status LEDs

Jumpers

Hardware Assembly

USB Programming (UART1)

GNSS Antenna

JST Connector (UART3)

Radio Transceivers

Breakout Pins

BlueSMiRF Header (UART2)

Software Overview

CH342 USB Driver

GNSS Software

QGNSS Software

Connecting to the LG290P

Configure the LG290P

PyGPSClient

Installation

Connecting to the LG290P

Terminal Emulator

Arduino IDE

SparkFun LG290P Quadband RTK GNSS Arduino Library

Resources

Product Resources

Additional Resources

🏭 Manufacturer's Resources

Troubleshooting Tips

USB Programming (`UART1`)

JST Connector (`UART3`)

BlueSMiRF Header (`UART2`)