Lord MicroStrain 3DM-CX5 Series User manual

3DM-CX5-GNSS/INS
GNSS-Aided Inertial Navigation System
LORD
USER MANUAL

MicroStrain® Sensing Systems
459 Hurricane Lane
Williston, VT 05495
United States of America
Phone: [phone]
www.microstrain.com
[e-mail]
[email protected]
Copyright © 2019 LORD Corporation
Document 8500-0084 Revision B
Subject to change without notice.

3DM-CX5-GNSS/INS
User Manual
Table of Contents
1. System Overview 1
2. Sensor Overview 2
2.1 Components 3
2.2 Interface and Indicators 4
3. Basic Setup and Operations 5
3.1 Software Installation 6
3.2 System Connections 7
3.3 Software Interface 8
3.3.1 Interactive Help Menu 9
3.4 Sensor Communication 9
3.5 GNSS Satellite Link 11
3.6 Sensor Settings 11
3.6.1 Saving Configurations 12
3.7 Data Monitoringand Recording 13
3.8 View Recorded Data 14
4. Sensor Measurements 16
4.1 Direct Sensor Measurements (IMU Outputs) 17
4.2 Computed Outputs 19
4.3 Sensor Reference Frames 21
4.3.1 Geodetic Frame 21
4.3.2 North East Down (NED) Frame 22
4.3.3 Sensor Frame 23
4.3.4 Platform Frame 24
5. Performance Optimization 26
5.1 Gyroscope Bias 26

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5.2 Tare Mounting Pitch-Roll 27
5.3 Magnetometer Auto Calibration 28
5.3.1 Enable 28
5.3.2 Capture 29
5.4 Magnetometer Manual Calibration 30
5.5 Estimation Filter Aiding 33
5.6 Heading Aiding Settings 34
5.6.1 Bias Convergence 35
5.7 Adaptive Anomaly Rejection 35
5.7.1 Gravity Adaptive 35
5.7.2 Mag Adaptive 36
5.8 Angular Rate andAcceleration Limits 37
5.9 Communications Bandwidth 37
5.10 Platform Frame Transformation 37
5.11 Estimation Filter Operation 37
5.12 Estimation Filter Convergence 39
5.12.1 Initial Convergence 39
5.12.2 Output Uncertainty 40
5.13 Vibration Isolation 40
5.14 IMU Sensor Calibration 40
5.15 Temperature Compensation 40
5.16 Import and Export Settings 40
6. Sensor Installation 42
6.1 Sensor Mounting 42
7. OEM System Integration 43
7.1 Data Communications Protocol (DCP) 43
7.1.1 Packet Builder 44

3DM-CX5-GNSS/INS
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7.1.2 Sensor Direct Mode 44
7.2 Sensor Wiring 46
7.3 Sampling on Start-up 47
7.4 Connecting to a Datalogger 48
7.5 Using Wireless Adapters 48
8. Troubleshooting 49
8.1 Troubleshooting Guide 49
8.2 Repair and Calibration 53
8.3 Maintenance 53
8.4 Technical Support 54
9. Parts and Configurations 55
9.1 Standard Configurations 55
9.2 Accessories 57
9.3 Sales Support 57
10. Specifications 58
11. Reference Diagrams 59
11.1 Sensor Dimensionsand Origin 59
11.2 GNSS Antenna Specifications 60
11.3 Power Supply Specifications (RS232kits only) 61
11.4 Communication andPower Cables 62
12. Reference Documents 64

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1. System Overview
The LORD Sensing 3DM-CX5 family of industrial-grade inertial sensors provides a wide range of triaxial
inertial measurements and computed attitude and navigation solutions.
In all models, the Inertial Measurement Unit (IMU) includes direct measurement of acceleration and
angular rate, and some also offer atmospheric pressure readings. In models that include a Kalman Filter,
sensor measurements are processed through an Extended Kalman Filter (EKF) to produce highly
accurate computed outputs. The 3DM-CX5 features include extremely stable and low-noise gyros, a new
accelerometer with noise densities as low as 25 µg/√Hz, and a multi-constellation GNSS receiver. The M7
and M4 dual Cortex processors run a new Auto-Adaptive EKF. The Kalman filter enables compensation
for magnetic and linear acceleration anomalies as applicable to the model. It also provides sensor bias
tracking, auto-zero update options (ZUPT), and user adjustable sensor noise factors. All sensors are fully
temperature-compensated and calibrated over the full operating temperature range.
The use of Micro-Electro-Mechanical System (MEMS) technology allows for small, lightweight devices.
Sensors are integrated into customer systems using serial communication protocols such as RS422,
RS232 and USB. The LORD Sensing MIP Monitor software can be used for device configuration, real
time measurement monitoring, and data recording. The LORD Sensing MIP Data Communications
Protocol (DCP) that is used to communicate with LORD Sensing inertial sensors is also available for users
who want to develop customized software solutions. Because of the unified set of commands across the
sensor family, it is easy to migrate code from one inertial sensor to another.
Common applications of LORD Sensing inertial sensor products include vehicle health monitoring,
platform stabilization, down- hole and drilling operations, and inertial navigation systems such as
unmanned air and ground vehicles and personal navigation systems.

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2. Sensor Overview
The 3DM-CX5-GNSS/INS is a high-performance, industrial-grade GNSS-Aided Inertial Navigation
System (GNSS/INS) that combines micro inertial sensors and a high- sensitivity embedded Global
Navigation Satellite System (GNSS) receiver for use in a wide range of industrial - grade applications,
such as unmanned vehicle navigation, robotic control, platform stabilization, motion tracking and analysis,
vehicle health monitoring, and device aiming.
The 3DM-CX5-GNSS/INS combines the strengths of an integrated multi-axis gyroscope, accelerometer,
and magnetometer, in combination with GNSS, temperature and pressure readings to provide highly
accurate position, velocity, attitude (including heading), and inertial measurements. All sensor
measurements are temperature- compensated and are mathematically aligned to an orthogonal
coordinate system. The combination of sensors, environmental compensation, and dual on- board
processing with an Auto-Adaptive Extended Kalman Filter (EKF) allows the 3DM-CX5-GNSS/INS to
perform well in a wide variety of applications that require low noise, drift, gain, and offset errors. Uncertainty
monitoring, scale factor estimation, and bias estimation outputs are available. Settings for sensor filtering,
sensor noise, and sensor bias, offer many adjustments for specific application needs.
The 3DM-CX5-GNSS/INS communicates through a serial connection and is monitored by a host
computer. A detachable GNSS antenna is plugged into the sensor via a non-magnetic adapter cable and
connector and positioned with unobstructed line of sight to the sky to obtain satellite links. Sensor
measurements and computed outputs can be viewed and recorded with the LORD Sensing MIP Monitor
software that is available as a free download from the LORD Sensing website. Alternatively, users can
write custom software with the LORD Sensing open source data communication protocol. The data is time-
aligned and available by either polling or continuous stream.
Figure 1. 3DM-CX5-GNSS/INS Sensor

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2.1 Components
The 3DM-CX5-GNSS/INS Inertial Sensor can be purchased by itself or as part of a Connectivity Kit.
All software, drivers, and links to detailed documentation are included with the sensor purchase. For
a complete list of available configurations, accessories, additional system products, and ordering
information.
Item
Description
Model
LORD Sensing
Part Number
A
3DM-CX5-GNSS/INS Inertial
Sensor
GNSS/INS 8G,
300 DPS*
6271-4260
MIP Monitor Software Suite http://www.microstrain.com/software
* For additional options available see Specifications on page 63
USB Development Kit
B
USB Communication Cable
--
6212-3009
C-Series Connectivity Board
Ribbon Cable
RS232 Development Kit
C
RS232 Communication Cable
--
6212-3010
RS232 Power Supply and Plug
Adapters
C-Series Connectivity Board
Ribbon Cable
Table 1. 3DM-CX5-GNSS/INS Components

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2.2 Interface and Indicators
The 3DM-CX5-GNSS/INS sensor interface includes a communications and power input connector and
a GNSS antenna port. The sensor is installed using the mounting and alignment holes as needed.
The indicators on the 3DM-CX5-GNSS/INS include a device status indicator and the device information
label. The table below describes the basic status indicator behavior. The device information label includes
the sensor frame diagram (axis orientation), which will be critical during device installation.
Indicator
Behavior
Device Status
device status
indicator
OFF
no power applied
rapid flash
streaming data with no GNSS
lock
steady blink
streaming data with GNSS
lock
slow pulse
idle mode, awaiting
commands
Figure 2. Sensor Indicator Behaviors

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3. Basic Setup and Operations
To acquire sensor measurements and computed outputs, the 3DM-CX5-GNSS/INS uses a host
computer, and TTL SERIAL or USB communications port, and applicable software. The LORD Sensing
MIP Monitor software is provided with the system and includes all functions needed for sensor
configuration and data acquisition. Users may also utilize the LORD Sensing MIP Data Communications
Protocol (DCP) to write custom software applications with expanded or specific feature sets needed for
the application. MIP Monitor includes a message building tool that can be used to streamline this process.
For more information,
see OEM System Integration on page 51 .
In this section, hardware and software setup is described, including an overview of the MIP Monitor
software menus required to configure a sensor and begin data acquisition. This is not a complete
demonstration of all system or software features and capabilities.
Figure 3. Viewing Sensor Data with MIP Monitor
Do not put the 3DM-CX5-45 in contact with, or in close proximity to,
magnets. Magnets may disrupt operation and cause magnetization of internal components, which can affect
magnetometer performance. If magnetization is suspected, use a degaussing tool to demagnetize.