QUECTEL LC76G Series GNSS Positioning Module User Guide

LC76G Series
EVB User Guide

LC76G Series GNSS Positioning Module

GNSS Module Series
Version: 1.0
Date: 2023-04-21
Status: Released

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Legal Notices

We offer information as a service to you. The provided information is based on your requirements and we make every effort to ensure its quality. You agree that you are responsible for using independent analysis and evaluation in designing intended products, and we provide reference designs for illustrative purposes only. Before using any hardware, software or service guided by this document, please read this notice carefully. Even though we employ commercially reasonable efforts to provide the best possible experience, you hereby acknowledge and agree that this document and related services hereunder are provided to you on an “as available” basis. We may revise or restate this document from time to time at our sole discretion without any prior notice to you.

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a) We acknowledge no liability for any injury or damage arising from the reliance upon the information.
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c) While we have made every effort to ensure that the functions and features under development are free from errors, it is possible that they could contain errors, inaccuracies, and omissions. Unless otherwise provided by valid agreement, we make no warranties of any kind, either implied or express, and exclude all liability for any loss or damage suffered in connection with the use of features and functions under development, to the maximum extent permitted by law, regardless of whether such loss or damage may have been foreseeable.
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Copyright © Quectel Wireless Solutions Co., Ltd. 2023. All rights reserved.

Safety Information

The following safety precautions must be observed during all phases of operation, such as usage, service or repair of any terminal incorporating Quectel LC76G series module. Manufacturers of the terminal should distribute the following safety precautions to users and operating personnel, and incorporate them into all manuals supplied with the product. Otherwise, Quectel assumes no liability for customers’ failure to comply with these precautions.

| Ensure that the product may be used in the country and the required environment, as well as that it conforms to the local safety and environmental regulations.
---|---
| Keep away from explosive and flammable materials. The use of electronic products in extreme power supply conditions and locations with potentially explosive atmospheres may cause fire and explosion accidents.
| The product must be powered by a stable voltage source, while the wiring must conform to security precautions and fire prevention regulations.
| Proper ESD handling procedures must be followed throughout the mounting, handling and operation of any devices and equipment incorporating the module to avoid ESD damages.

About the Document

Document Information

Revision History

Introduction

This document provides information on the steps needed to evaluate the Quectel LC76G series module using the Evaluation Board (EVB). The EVB is a convenient tool that allows you to become familiar with the module.
Specifically, the document is divided into several sections:

• Chapter 2 provides the general overview of EVB kit.
• Chapter 3 describes the EVB user interfaces.
• Chapter 4 describes how to test the module and upgrade the firmware via QGNSS tool.
• Chapter 5 describes the installation of EVB and antenna.
• Chapter 6 describes how to measure power consumption for the module.
• Chapter 7 provides the EVB framework.
• Chapter 8 describes the common problems and troubleshooting.
• Chapter 9 describes the cautions.
• Chapter 10 is an appendix, which summarizes the relevant documents, terms and abbreviations appearing herein.

NOTE
Request the software tool QGNSS from Quectel Technical Support (support@quectel.com).
1.1. Special Mark
Table 1: Special Mark

General Overview

2.1. EVB Kit
The EVB kit includes: Evaluation Board (EVB), active GNSS antenna, Type-B USB cable, bolts and coupling nuts.
The EVB kit contents are shown in the figure below. Check Table 2: List of Kit Components for details.
Table 2: List of Kit Components

Antenna Size: 47 mm × 55 mm × 16.2 mm
Cable Length: 3000 mm
The GNSS antenna supports:
GPS L1 C/A
GLONASS L1
Galileo E1
BDS B1I, BIC
QZSS L1 C/A
SBAS L1| 1
Others| Bolts and Coupling Nuts| 4 pairs

NOTE
Request Quectel Technical Support (support@quectel.com) for details about Quectel Active GNSS Antenna.

2.2. Connect Cable and Antenna to EVB
The connection between the EVB and its components is shown in the figure below. NOTE
Make sure that the active GNSS antenna is placed with a clear line of sight to the sky.

EVB Interfaces

3.1. EVB Top View
EVB top view is shown in the figure below. 3.2. EVB Interfaces
The EVB interfaces are detailed in the table below.
Table 3: Detailed EVB Interfaces

DC power supply: 4.5-5.5 V, Typ. 5.0 V
Current capability should be > 100 mA
Communication Interface| J509
USB to UART| Supports RTCM and standard NMEA message, PAIR/PQTM message and binary data, and firmware upgrade.
i.
SMA Connectors| J103
Antenna connector| Used for connecting GNSS antenna.
U512
1PPS connector| Used for testing 1PPS signal.
Signal Indication| D514
Indication LEDs| POWER (Red)| Bright: EVB is powered well. i,
Extinct: EVB is not powered.
VCC (Green)| Bright: Module is powered well.
Extinct: Module is not powered.
D520
Indication LEDs| 1PPS (Red)| Flashing: Successful position fix. Frequency: 1 Hz.
Extinct: No position fix.
TXD
(Green)| Unsupported.
Switches and Buttons| S201
Module power switch| Powers the module VCC on/off.
ir S503
RESET| Short press the button to reset the module.

The J402 test point of LC76G EVB is shown below:
Table 4: J402 Pin Detailed Description

antenna in power saving mode
8| 15| U103: Pin 15| –| Reserved
9| 17| U103: Pin 17| DI| I2C_SCL: I2C serial clock
10| 19| U103: Pin 19| –| Reserved
11| 21| U103: Pin 21| DO| GEOFENCE: Indicates geofence status
12| 23| U103: Pin 23| DO| 3D_FIX: 3D position fix indication
13| 25| U103: Pin 25| DI| SPI_CLK: SPI clock signal
14| 27| U103: Pin 27| DI| SPI_MOSI: SPI master output,
slave input
15| No label| –| –| NC
16| No label| –| –| NC
17| 28| GND| –| Ground
18| 26| U103: Pin 26| DO| SPI_MISO: SPI master input, slave output
19| 24| U103: Pin 24| DI| D_SEL: Selects UART/SPI interface to download
20| 22| U103: Pin 22| DO| JAM_IND: Jamming indication
21| 20| U103: Pin 20| DI| SPI_CS: SPI chip-select
22| 18| U103: Pin 18| –| Reserved
23| 16| U103: Pin 16| DIO| I2C_SDA: I2C serial data
24| 14| U103: Pin 14| PO| VDD_RF: Power supply for external RF components
25| 12| GND| –| Ground
26| 10| GND| –| Ground
27| 8| U103: Pin 8| PI| VCC: Main power supply
28| 6| U103: Pin 6| PI| V_BCKP: Backup power supply for backup domain of module
29| 4| U103: Pin 4| DO| 1PPS: 1 pulse per second
30| PIN2| U103: Pin 2| DO| TXD: Transmits data

NOTE

1. Te s t points of J402 are arranged clockwise, and their serial numbers are shown in Figure 3: EVB Top View.
2. A J402 test point refers to the module’s corresponding function. For detailed descriptions, see document [1] hardware design.

Test and Firmware Upgrade via QGNSS Tool

This chapter explains how to use the QGNSS software tool for verifying the status of GNSS module and for firmware upgrade. For more information about QGNSS use, see document [2] QGNSS user guide.

4.1. Test via QGNSS

Step 1: Assemble the EVB components.
Step 2: Connect the EVB and the PC with a Type-B USB cable then flip the power switch (S201) of the module to ON position to power on the module.
Step 3: Start the QGNSS and click “Device” and “Set Device Information” (default baud rate: 115200 bps 1).

Step 4: Click the “Connect or disconnect” button. The interface shown in the figure below appears once the module is connected.

4.2. GNSS Interface Explanation
You can view GNSS information, such as C/N0 message, time, position, speed, and precision in the QGNSS interface. See the following table to find out more about these parameters.
Table 5: QGNSS Interface Explanation

Icon

Explanation

This sky view interface shows the position of the satellites in use.

1. The left column icons show the satellites in use and their numbers.

• BDS: 17
• GLO (GLONASS): 5
• GPS: 12
• GAL (Galileo): 0
• QZSS: 0
• NAVIC: 0
• SBAS: 0

Icon

2. The sky view on the right shows the position of the satellites in use.
   GPS satellite
   BD S satellite
   GLONASS satellite
   Galileo satellite
   QZSS satellite
   NavIC satellite

• PRN 30 C/N0 is 39 dB-Hz.
• Column in bright red mean that the navigation data of the satellites are in use.
• PRN 1 C/N0 is 21 dB-Hz.
• Column in light red means that the navigation data of the satellites are not in use.

• Longitude (unit: °)
• Latitude (unit: °)
• Altitude (MSL) (unit: m)
• Receiver speed (unit: km/h)
• Horizontal dilution of precision
• Position dilution of precision
• Fix Mode: 2D, 3D
• Quality Indicator: DGNSS, DGPS, GPS SPS, Float RTK and Fixed RTK modes
• Date: UTC date
• Time: UTC time
• Total Times
• Fixed Points
• RTK Fixed
• RTK Float
• Age of differential GPS data
• TTFF (unit: s)
• 2D accuracy (unit: m)
• 3D accuracy (unit: m)

4.3. Firmware Upgrading
Power on the EVB before upgrading the firmware, see Chapter 4.1 Test via QGNSS for details.
Firmware upgrading steps:
Step 1: Open QGNSS tool, and click “Tools” and select “Firmware Download” in the drop-down box.

Step 2: Select the appropriate “Download Baudrate” in the drop-down box of “Settings”.

Step 3: Click the “Open Config File” button to select Config file, e.g., “flash_download.cfg”.

Step 4: Click the “Run” button and then short-press on the reset button after the progress bar prompts you to reset the module.

Step 5: Upon successful firmware upgrading, the QGNSS tool’s progress bar on the screen will indicate “100 %”.

NOTE
Make sure the module is in Continuous mode before upgrading firmware.

EVB and Antenna Installation

5.1. GNSS Antenna Installation
The installation environment affects antenna reception performance and satellite visibility, which in turn affect the positioning performance of a GNSS receiver. In addition, antenna’s position and direction can also impact its reception performance. Therefore, it is important to avoid obstacles and interference when installing antenna. Place the ceramic patch antenna horizontally and make sure it faces toward the sky.
If dynamic testing is required, make sure that the GNSS antenna is firmly fixed to the device under test so as to avoid any movement or vibration with respect to the device.

5.2. EVB Installation
If dynamic testing is required, make sure the EVB is firmly fixed to the device under test so as to avoid any movement or vibration with respect to the device.

Measuring Power Consumption

6.1. Power Consumption at Different Stages
Module power consumption is measured in four stages: acquisition and tracking (including almanac update), tracking (almanac update is over), upon entering ALP mode and Backup mode.

• Acquisition and tracking (including almanac update): 0 s to 12.5 min
• Tracking (almanac update is over): > 12.5 min
• Entering ALP mode
• Entering Backup mode

NOTE
The EVB works normally. After entering the tracking mode, the module enters the ALP mode when the $PAIR732,1*21 command is sent. Then, the power consumption of the ALP mode can be measured.
Record the average value after the power consumption of the ALP mode is stable. For more information, see document [3] protocol specification.

6.2. Power Consumption Measurement for VCC or in ALP Mode
Before measuring the power consumption of VCC or in ALP mode, you must connect the components to the EVB to ensure that the module can communicate and fix it normally. See Chapter 4.1 Test via QGNSS.
Detailed steps for measuring power consumption of VCC or in ALP mode with an ammeter:
Step 1: Switch off the power supply (S201) of the module and pull out the VCC_MODULE jumper cap (J102). Connect the ammeter in series to the pins of J102 as shown below.
Step 2: Switch on the power supply (S201) of the module and read the ammeter.

Detailed steps for measuring power consumption of VCC or in ALP mode with a power consumption meter:
Step 1: Switch off the power supply (S201) of the module and pull out the VCC_MODULE jumper cap (J102). Make sure the positive pole of the power consumption meter is to be connected to pin 2 (without arrow silkscreen) of J102, and the negative pole is connected to GND.
Step 2: Switch on the power supply (S201) of the module and read the power consumption meter.

NOTE
The EVB works normally. After entering the tracking mode, the module enters the ALP mode when the $PAIR732,1*21 command is sent. Then, the power consumption of the ALP mode can be measured.
Record the average value when the power consumption in the ALP mode is stable. For more information, see document [3] protocol specification.

6.3. V_BCKP Power Consumption Measurement
Before measuring the V_BCKP power consumption, you must connect the components to EVB to ensure that the module can communicate and fix normally. See Chapter 4.1 Test via QGNSS.
Detailed steps for measuring V_BCKP power consumption with an ammeter:
Step 1: Switch off the power supply (S201).
For LC76G (AB, PA), pull out the V_BACK_3V3 jumper cap (J205). Connect the ammeter in series to the pins of J205, as shown below.

For LC76G (PB), pull out the V_BACK jumper cap (J207). Connect the ammeter in series to the pins of J207, as shown below.

Step 2: Switch on the power supply and read the ammeter.
Detailed steps for measuring V_BCKP power consumption with power consumption meter:
Step 1: Switch off the power supply (S201) of the module. Ensure the positive pole of the power consumption meter is connected to the head pin of V_BACK_3V3, and the negative pole is connected to GND.
For LC76G (AB, PA), pull out the V_BACK_3V3 jumper cap (J205). Then, ensure the positive pole of the power consumption meter is connected to pin 2 (with arrow silkscreen) of J205, and the negative pole is connected to GND.

For LC76G (PB), pull out the V_BACK jumper cap (J207). Then, ensure the positive pole of the power consumption meter is connected to pin 2 (without arrow silkscreen) of J207, and the negative pole is connected to GND.

Step 2: Switch on the power supply (S201) of the module and read the power consumption meter.

NOTE

1. Adjust the current resolution when using the power consumption meter.
2. The power value can be calculated according to the following formula: P = V Supply× I Test.
3. When measuring the V_BCKP power consumption in Backup mode, ensure that the module has entered Backup mode, and then remove the jumper cap of VCC_MODULE (J102) to cut off the power supply of VCC. For more information about the way to enter/exit Backup mode, see document [1] hardware design.

EVB Framework

The power is supplied to EVB via Type-B, and then power to GNSS module via a Linear voltage regulator (LDO). GNSS module outputs the signals from communication interface on EVB via USB-to-UART Bridge Chip (CP2102N). There are an antenna interface and a control button on EVB. All functions of the module are available, including debugging.

NOTE
The operating voltage of LC76G (AB, PA) is 3.3 V, while the operating voltage of LC76G (PB) is 1.8 V.

Common Problems and Troubleshooting

1. Unable to find COM port in the Device Manager when EVB is connected to PC with a USB cable.
    Check that the EVB communication interface is properly connected to the PC.
    Verify that CP210x Driver has been installed successfully.

2. Communication interface not outputting any messages or commands.
    Check that the power supply indication LED on the EVB is illuminated.
    Verify that the jumper cap(s) is(/are) connected correctly, as shown in Figure 1: EVB and Components.
    Ensure that the module’s power supply is normal.

3. Module unable to search for satellite signals.
    If there is no transponder indoors, test the module in an open-sky environment.

4. Module unable to upgrade.
    Verify whether the module is in normal operating mode.
    Check that the downloaded firmware is correct.
    Confirm that the correct COM port has been selected.

NOTE
For the problem(s) that cannot be solved, please contact Quectel Technical Support (support@quectel.com).

Cautions

• Make sure to conduct tests under the same environment when comparing different parameters of GNSS modules.
• Note that parameters, such as cold start, acquisition and tracking, may be defined differently by chip suppliers.
• Ensure that the measurement method is correct. If there are significant differences between parameters tested via EVB and those provided by Quectel, please contact Quectel Technical Support.
• Note that momentary data obtained from measurement cannot always be regarded as reference data, because it may be affected by various factors, such as satellite positions at different times, environmental conditions, temperature, humidity and altitude.
• Keep in mind that the QGNSS Tool may updated periodically to fix bugs or improve performance.
  Please make sure that you are using the latest version of the tool.

Appendix References

Table 6: Related Documents
Document Name
[1] Quectel_LC76G_Series_Hardware_Design
[2] Quectel_QGNSS_User_Guide
[3] Quectel_LC26G&LC76G&LC86G_Series_GNSS_Protocol_Specification

Table 7: Terms and Abbreviations

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