Skip to content

Hardware Overview

Banner

Introduction

  • SparkPNT GNSS Flex Module - LG290P & IM19 IMU
    SKU: GPS-29469

    Product Thumbnail

    Tilt Compensation

    The IM19 IMU from Feyman (FMI) fuses MEMS sensor and GNSS RTK positioning data to deliver high-precision attitude measurement, with roll and pitch accurate to within 0.05 degrees. This kind of superb accuracy has widespread uses in industrial applications such as tilt RTK surveys (where RTK poles need not be held straight vertical as the IM19 can calculate a virtual digital level at any tilt angle), agriculture machine automation, and dead reckoning.

    When configured, fed with the LG290P Pulse-Per-Second signal and NMEA GGA, RMC and GST messages, and calibrated, the IM19 will output proprietary NMEA messages containing the compensated position and roll, pitch and yaw. By default, the LG290P COM3 TX is linked to the IM19 UART2 RX to carry the required NMEA messages. However, this can be changed via jumper links on the Flex Module, if necessary.

  • SparkPNT GNSS Flex modules are plug-in boards featuring different GNSS receivers. They are designed to be easily swapped for repairs and pin-compatible for upgrades. The boards have two 2x10-pin, 2mm pitch female headers connecting to carrier boards. For the LG290P GNSS receiver, these pins will break out the UART (x2) and I2C* interfaces, along with the PPS and event signals using a standardized pinout. Additionally, these pins break out the two UART interfaces of the IM19 IMU.

    This SparkPNT GNSS Flex module combines the Quectel LG290P GNSS receiver with the IM19 Inertial Measurement Unit for tilt compensation or dead reckoning. The LG290P module is a quad-band, multi-constellation, high-precision, RTK GNSS receiver. The module can simultaneously receive 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 services* (BDS PPP-B2b, QZSS CLAS, MADOCA-PPP, and Galileo HAS), RTCM, 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, effectively mitigating multiple narrow-band interference sources and significantly improving 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.

    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.

Design Files

  • Design Files

  • Manipulate 3D Model
    Controls Mouse Touchscreen
    Zoom Scroll Wheel 2-Finger Pinch
    Rotate Left-Click & Drag 1-Finger Drag
    Move/Translate Right-Click & Drag 2-Finger Drag

    Board Dimensions
    Dimensions of the LG290P GNSS Flex module.

    Need more measurements?

    For more information about the board's dimensions, users can download the KiCad files for this board. These files can be opened in KiCad and additional measurements can be made with the measuring tool.

    KiCad - Free Download!

    KiCad is free, open-source CAD program for electronics. Click on the button below to download their software. (*Users can find out more information about KiCad from their website.)

    📏 Measuring Tool

    This video demonstrates how to utilize the dimensions tool in KiCad, to include additional measurements:

    QR code to play video

Board Layout

The GNSS Flex system is designed around two 2x10-pin, 2mm pitch headers used mate the two types of boards. A standardized pin layout, keeps the ecosystem pin-compatible for upgrades and allows board to be easily swapped for repairs. Depending on the capabilities of the GNSS receiver, these pins will breakout the USB, UART (x4), I2C, and SD card interfaces along with any PPS or event signals of the GNSS receiver.

The LG290P GNSS Flex module has the following features:

Layout

Layout of the major components on the LG290P GNSS Flex module.

  1. LG290P GNSS Receiver
    The Quectel LG290P GNSS receiver
  2. GNSS Flex Headers
    Two sets of 2x10 pin, 2mm pitch female headers for connecting a GNSS Flex module to carrier boards
  3. IM19 IMU (optional)
    An optional Feyman IM19 attitude module to provide tilt compensation in surveying applications
  4. Antenna L1/L2/L5/E6 U.FL Connector
    An U.FL connector for attaching an external GNSS antenna

LG290P GNSS Module

One of the centerpieces of the GNSS Flex module, 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.

QR code to product video

  • LG290P GNSS module
    The LG290P GNSS module on the LG290P GNSS Flex module.

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
    • SPI3 (x1)
    • I2C3 (x1)
  • Operating temperature: -40°C to +85°C

Power Consumption

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

Mode Power (mW) Current (mA)
Acquisition 300.3 91
Tracking 300.3 91
Backup 39.6 0.012

Frequency Bands

The LG290P module is a multi-band, multi-constellation GNSS receiver. 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, L1C1, L5, L2C
  • GLONASS: L1, L2
  • Galileo: E1, E5a, E5b, E6
  • BDS: B1I, B1C, B2a, B2b, B2I, B3I
  • QZSS: L1 C/A, L1C1, L5, L2C
  • NavIC: L5
  • SBAS: L1 C/A
  • L-band PPP2:
    • 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.

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

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:

Position 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"
IM19 Attitude Module

When configured and calibrated, the IM19 attitude module can fuses IMU sensor and GNSS RTK positioning data to deliver compensated position. The accuracy, displayed in the table below, should also be considered when implemented.

Tilt Angle Accuracy
0° - 30° 1cm
<60° 2cm
RTK Corrections

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

Tip

For the best performance, we highly recommend that users configure the module to utilize/provide RTK corrections with a compatible L1/L2/L5/L6 GNSS antenna and utilize a low-loss cable.

IM19 IMU (Optional)

The other centerpiece of the GNSS Flex module is the IM19 attitude module from Feyman Inc., which fuses MEMS sensor and GNSS RTK positioning data to deliver high-precision attitude measurement, with roll and pitch accurate to within 0.05 degrees. This kind of superb accuracy has widespread uses in industrial applications such as tilt RTK surveys (where RTK poles need not be held straight vertical as the IM19 can calculate a virtual digital level at any tilt angle), agriculture machine automation, and dead reckoning.

When configured, fed with the LG290P Pulse-Per-Second signal and NMEA GGA, RMC and GST messages, and calibrated, the IM19 will output proprietary NMEA messages containing the compensated position and roll, pitch and yaw. By default, the LG290P COM3 TX is linked to the IM19 UART2 RX to carry the required NMEA messages. However, this can be changed via jumper links on the Flex Module, if necessary.

  • IM19 attitude module
    The IM19 attitude module on the LG290P GNSS Flex module.

Features:

  • Self-calibration Technique
  • Initialization: <2s
  • Power: 0.33W
  • Data Rate: 100Hz
  • Attitude Accuracy: ±0.05° (Pitch/Roll)
  • Heading Accuracy: ±0.5° (Yaw)


  • Gyroscope
    • Bias Stability: ±0.2°/s
    • Range: ±1000°/s
  • Accelerometer
    • Bias Stability: ±5mg
    • Range: ±8g

Info

Please refer to the hookup guide linked below, for the operation of the IM19 attitude module in tilt-compensation applications:

Position Accuracy

When configured and calibrated, the IM19 attitude module can fuses its IMU sensor data with the received GNSS RTK positioning data to deliver a tilt compensated position.

Tilt Angle Accuracy
0° - 30° 1cm
<60° 2cm
LG290P GNSS Module

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. Its accuracy, displayed in the table below, should also be considered when implemented.

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"

GNSS Flex Headers

The GNSS Flex system is designed around two 2x10-pin, 2mm pitch headers used mate the two types of boards. A standardized pin layout, keeps the ecosystem pin-compatible for upgrades and allows boards to be easily swapped for repairs. For the LG290P GNSS receiver, these pins will breakout the UART (x2) and I2C interfaces along with a PPS, event, and LED status indication signals from the GNSS receiver. Additionally, these pins break out the two UART interfaces of the IM19 attitude module.

Peripherals and I/O pins

The peripherals and I/O pins on the LG290P GNSS Flex module.

Below, are the features that are available from the LG290P GNSS receiver.

Supported Interfaces:

  • UART (x2) (1)
  • SPI3
  • I2C3
  • Event Trigger
  • Timing Signal
  • RTK Signal
  1. One of the three UART ports is piped to the IM19 module

Below, are the features that are available from the IM19 attitude module.

Supported Interfaces:

  • UART (x2)
  • Timing Signal (1)
  1. The timing signal comes from the LG290P GNSS module

The headers of the GNSS Flex system supports up to four UART ports. On this GNSS Flex module, these are connected to both the GNSS receiver and IM19 attitude module.

UART interface
The UART ports on the LG290P GNSS Flex module.

LG290P

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

UART interface
The UART ports from the LG290P on the GNSS Flex module.

  • The UART1 and UART2 ports of the LG290P GNSS module are broken out to the headers of the GNSS Flex system. These can be used to interact with the LG290P.
  • The TX pin of the UART3 port from the LG290P GNSS module is piped directly to the RX pin of the IM19 attitude module's UART2 port.

Default Configuration

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

  • Baudrate: 460800bps
  • Data Bits: 8
  • Parity: No
  • Stop Bits: 1
  • Flow Control: None
  • Protocols:
    • NMEA 0183
    • RTCM 3.x
LG290P Pins of GNSS Flex Headers
UART1 TXD1/RXD1
UART2 TXD2/RXD2
UART Protocols

By default, these 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 that follows a data format similar to 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.

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

IM19

The IM19 attitude module has two UART ports, which operate separately.

UART interface
The UART ports from the IM19 on the LG290P GNSS Flex module.

  • The UART1 port of the IM19 module is broken out to the headers of the GNSS Flex system, on pins TXD3 and RXD3. These pins should be used to configure the IM19 module.
  • The UART2 port of the IM19 module is used to receive GNSS data from the GNSS receiver and output the tilt compensated data.
    • By default, the RX pin receives data from the UART3 port of the LG290P GNSS module.
      • Users can modify the jumpers on the top of the GNSS Flex module, to utilize the TXD1, TXD2, or RXD4 pins (of the GNSS Flex headers) instead.
    • Once IM19 module is configured and calibrated, the TX pin outputs the tilt compensated data to the TXD4 pin on the GNSS Flex headers.

Default Configuration

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

  • Baudrate: 115200bps
  • Data Bits: 8
  • Parity: No
  • Stop Bits: 1
  • Flow Control: None
  • Protocols:
    • AT Commands
    • Proprietary Data Formats
      • MEMS Raw data protocol
      • GNSS Raw data protocol
      • Binary NAVI positioning data protocol
IM19 Pins of GNSS Flex Headers
UART1 TXD3/RXD3
UART2 TXD4

From the module, the PPS output signal is a 3.3V signal output. In order to receive tilt-compensated data from the IM19 attitude module, this pin needs to be configured to provide a timing pulse at the same rate as the PVT solutions.

I/O for PPS signal
The PPS signal's output on the LG290P GNSS Flex module.

The RTK PTH pin operates as both the RTK_LED status indicator for the RTK positioning and ANT_ON power control for the external LNA or active antenna power.

I/O for RTK signal
The RTK_LED pin on the LG290P GNSS Flex module.

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

  1. If the pin output is high, it indicates the module has entered the RTK fixed mode.
  2. If the pin output is low, it indicates that the module exited the RTK fixed mode.
  3. 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.

This pin can be triggered by inputs with an adjustable frequency and polarity.

Event trigger
The event pin on the LG290P GNSS Flex module.

This pin can be used to reset both the LG290P GNSS module and IM19 attitude module. Driving the pin LOW for at least 100ms triggers a restart of both modules.

Reset
The reset pin on the LG290P GNSS Flex module.

U.FL Connector

Users will need to connect a compatible GNSS antenna to the Antenna L1/L2/L5/E6 U.FL connector. The type of antenna used with the LG290P module affects the overall accuracy of the positions calculated by the GNSS receiver.

  • 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 an antenna with the LNA placed in the front.
  • There is no need to inject an external DC voltage for the GNSS antenna. Power is already provided from the LG290P module for the LNA of an active antenna.

GNSS antenna input

The U.FL connector to attach an external GNSS antenna to the LG290P GNSS Flex module.

Tip

For the best performance, we recommend users choose a compatible L1/L2/L5/E6 GNSS antenna and utilize a low-loss cable. Also, don't forget that GNSS signals are fairly weak and can't penetrate buildings or dense vegetation. The GNSS antenna should have an unobstructed view of the sky.

Jumpers

The are four jumpers on top of the LG290P GNSS Flex module that can be modified to change the source of the GNSS data for the IM19 attitude module.

Jumpers

The jumper on the top of the LG290P GNSS Flex module.

Never modified a jumper before?

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

  1. Feature Under Development

    Support for the L1C frequency band has not been implemented.

    ↩↩

  2. Feature Under Development

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

    ↩

  3. Feature Under Development

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

    ↩↩↩↩