LORD 3DM-GX4-45 User manual

LORD USERMANUAL
3DM-GX4-45™
GPS-Aided Inertial Navigation System (GPS/INS)

© 2014 LORDCorporation
MicroStrain®Sensing Systems
459 Hurricane Lane
Suite 102
Williston, VT 05495
United States of America
Phone: [phone]
Fax: [phone]
http://www.microstrain.com
[e-mail]
[e-mail]
Copyright © 2014 LORD Corporation
3DM®, 3DM-DH®, 3DM-DH3™, 3DM-GX1®, 3DM-GX2®, 3DM-GX3®, 3DM-GX4-15™, 3DM-GX4-25™, 3DM-GX4-45™,
3DM-GX4™, 3DM-RQ1™, AIFP®, Ask Us How™, Bolt-Link®, DEMOD-DC®, DVRT®, DVRT-Link™, EH-Link®,
EmbedSense®, ENV-Link™, FAS-A®, G-Link®, G-Link2™, HS-Link®, IEPE-Link™, Inertia-Link®, Little Sensors, Big Ideas.®,
Live Connect™, LXRS®, MathEngine®, MicroStrain®, MVEH™, MXRS®, Node Commander®, PVEH™, RHT-Link®, RTD-
Link™, SensorCloud™, SG-Link®, Shock-Link™, Strain Wizard®, TC-Link®, Torque-Link™, V-Link®, Watt-Link™, Wireless
Simplicity, Hardwired Reliability™, and WSDA®are trademarks of LORD Corporation.
Document 8500-0041 Revision D
Subject to change without notice.

3DM-GX4-45™Inertial Navigation System User Manual
Table of Contents
1. System Overview 7
2. Sensor Overview 8
2.1 Components 9
2.2 Interface and Indicators 10
3. Basic Setup and Operations 11
3.1 Software Installation 12
3.2 System Connections 13
3.3 Software Interface 14
3.3.1 Interactive Help Menu 14
3.4 Sensor Communication 15
3.5 GPS Link 16
3.6 Sensor Settings 16
3.6.1 Saving Configurations 18
3.7 Data Monitoring and Recording 19
3.8 Viewing Data 22
4. Sensor Measurements 23
4.1 Direct Sensor Measurements (IMU Outputs) 24
4.2 Global Positioning System (GPS) Outputs 26
4.3 Computed Outputs (Estimation Filter) 28
4.4 Sensor Reference Frames 31
4.4.1 Geodetic Frame 31
4.4.2 NorthEast Down (NED) Frame 32

3DM-GX4-45™Inertial Navigation System User Manual
4.4.3 Sensor Frame 33
4.4.4 Platform Frame 34
5. Performance Optimization 36
5.1 Magnetometer Calibration 36
5.2 Gyroscope Bias 39
5.3 Heading Drift and Compensation 40
5.4 Angular Rate and Acceleration Limits 41
5.5 Bandwidth 41
5.6 Platform Frame Transformation 41
5.7 GPSParameters 41
5.8 GPS Antenna Offset 42
5.9 Vehicle Dynamics Mode 43
5.10 Estimation Filter Operation 44
5.11 Estimation Filter Convergence 46
5.11.1 Initial Convergence 46
5.11.2 Bias Convergence 46
5.11.3 Output Uncertainty 46
5.12 Vibration Isolation 47
5.13 IMU Sensor Calibration 47
5.14 Temperature Compensation 47
6. Sensor Installation 48
6.1 Sensor Mounting 48
6.2 GPS Antenna Installation 49
7. OEMSystemIntegration 50

3DM-GX4-45™Inertial Navigation System User Manual
7.1 DataCommunications Protocol (DCP) 50
7.1.1 Packet Builder 51
7.1.2 Sensor Direct Mode 52
7.1.3 GPSDirect Mode 53
7.2 Sensor Wiring 54
7.3 Alternate GPS Equipment 55
7.3.1 GPSExternal Receiver 55
7.4 Sampling on Start-up 57
7.5 Connecting to a Datalogger 58
7.6 Using Wireless Adapters 58
8. Troubleshooting 59
8.1 Troubleshooting Guide 59
8.2 Repair and Calibration 64
8.3 Technical Support 65
9. Maintenance 66
10. Parts and Configurations 67
10.1 Standard Configurations 67
10.2 Accessories 69
10.3 Sales Support 70
11. Specifications 71
12. Safety Information 73
13. Addendum 74
13.1 Reference Diagrams 74
13.1.1 Sensor Dimensions and Origin 74

3DM-GX4-45™Inertial Navigation System User Manual
13.1.2 GPSAntennaSpecifications 75
13.1.3 Power Supply Specifications (RS232 kits only) 76
13.1.4 Communication and Power Cables 77
13.2 Reference Documents 78
13.3 Glossary 79

3DM-GX4-45™Inertial Navigation System User Manual System Overview
7
1. System Overview
The LORD MicroStrain®3DM-GX4™family of industrial grade inertial sensors provides a wide
range of triaxial orientation measurements and computed navigation solutions. In all models, the
Inertial Measurement Unit (IMU) includes direct measurement of acceleration, angular rate, and
atmospheric pressure. Sensor measurements are processed through an Extended or Adaptive
Kalman Filter (EKF/AKF) to produce high accuracy computed outputs. The computed outputs
vary between models and include: pitch and roll in the 3DM-GX4-15™IMU/VRU model, the full
attitude solution (pitch, roll, and yaw) in the 3DM- GX4- 25™AHRS model, and the full PVA
(position, velocity and attitude) solution in the 3DM-GX4-45™and 3DM-RQ1™GPS/INS models.
The Kalman filter provide EKF technologies to compensate 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 RS232 and USB. The LORD MicroStrain®MIP™Monitor software can be used for device
configuration, real time measurement monitoring, and data recording. The LORD MicroStrain®
MIP™Data Communications Protocol that is used to communicate with LORD MicroStrain ®
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 MicroStrain ®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.

3DM-GX4-45™Inertial Navigation System User Manual Sensor Overview
8
2. Sensor Overview
The 3DM-GX4-45™is a high-performance, miniature, Inertial Aided GPSNavigation System
(GPS/INS) that combines micro inertial sensors and a high- sensitivity embedded Global
Positioning System (GPS) 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-GX4-45™utilizes the strengths of integrated multi-axis gyroscopes, accelerometers,
and magnetometers in combination with GPS, temperature, and pressure readings to provide high
accuracy position, velocity, attitude (including heading), and inertial measurements. Each of the
integrated sensors is especially good at certain tasks, and it is the weighted combination of their
outputs that provides the best estimations for position, velocity and attitude . 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 Extended Kalman Filter (EKF) allow the 3DM-GX4-45™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, and settings for
sensor filtering, sensor noise, sensor bias, and more offer many adjustments for specific
application needs.
The 3DM- GX4- 45 ™communicates through a serial connection and is monitored by a host
computer. A detachable GPS antenna is plugged into the sensor and positioned with unobstructed
line of sight to the sky to obtain GPS satellite links. Sensor measurements and computed outputs
can be viewed and recorded with the LORD MicroStrain®MIP™Monitor software that is provided
with system starter kits, and also available as a free download from the LORD MicroStrain®
website. Alternatively, users can write custom software with the LORD MicroStrain®open source
data communication protocol. The data is time- aligned and available by either polling or
continuous stream.
Figure 1 - 3DM-GX4-45™Sensor

3DM-GX4-45™Inertial Navigation System User Manual Sensor Overview
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2.1 Components
The 3DM -GX4 -45™can be purchased by itself or in a starter kit that includes everything
needed to begin using it. The starter kits include the 3DM-GX4-45™inertial sensor, a serial
communications cable (either RS232 or USB), a power supply with country plug adapter
(RS232 kits only), an external GPS antenna with a three meter cable, a non-magnetic GPS
antenna adapter cable, and all software, drivers, and documentation. This manual covers all
items included in the starter kits. For a complete list of available configurations, accessories,
additional system products and ordering information see Parts and Configurations on page 67.
Item Description Quantity
A3DM-GX4-45™Inertial Sensor 1
BCommunications cable (USB or RS232) 1
CPower supply and country plug adapters (for RS232 only) 1
DGPS antenna with attached cable (3m SMA) 1
EGPS antenna cable adapter (non-magnetic MMCX-to-SMA) 1
-- MIP™Monitor Software Suite 1
-- User Manual, Quick Start Guide and Calibration Certificate 1
Table 1 - Components List

3DM-GX4-45™Inertial Navigation System User Manual Sensor Overview
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2.2 Interface and Indicators
The 3DM-GX4-45™sensor interfaces include a dual use communications and power input
connector and a GPS antenna port. The sensor is mounted using the mounting and alignment
holes as needed (see Sensor Mounting on page 48).
The indicators on the 3DM - GX4 - 45 ™include a device status indicator and the device
information label. Table 2 - Indicator Behaviors describes the basic status indicator behavior.
The device information label includes the sensor frame diagram (axis orientation) which will be
critical during device installation (see Sensor Frame on page 33).
Figure 2 - Interface and Indicators
Indicator Behavior Device Status
device status
indicator
OFF no power applied
rapid flash streaming data with no GPS lock
steady blink streaming data with GPS lock
slow pulse idle mode, awaiting commands
Table 2 - Indicator Behaviors

3DM-GX4-45™Inertial Navigation System User Manual Basic Setup and Operations
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3. Basic Setup and Operations
Do not bring sensors with magnetometers in contact or close
proximity with 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.
To acquire sensor measurements and computed outputs, the 3DM-GX4-45™is used with a host
computer capable of serial communication, and a software interface. The LORD MicroStrain®
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 MicroStrain®MIP™Data
Communications Protocol 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 50.
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. It is
intended as a quick start guide and is not a complete demonstration of all system or software
features and capabilities.
Figure 3 - Acquiring Sensor Data with MIP™Monitor

3DM-GX4-45™Inertial Navigation System User Manual Basic Setup and Operations
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3.1 Software Installation
NOTE
The MIP™Monitor Software Suite includes hardware drivers required for all
3DM-GX4™sensors. Sensors will not be recognized without these drivers.
To install MIP™Monitor Software Suite on the host computer, complete the following steps:
1. Launch the software installation menu by inserting the software CD or thumb drive
into the host computer or by running the Autorun.exe file from the software directory
in Windows®Explorer.
2. In the software installation menu select Install MIPMonitor Software and follow the on
screen prompts to completion.
3. If the sensor has internal magnetometers, select Install MIP Hard and Soft Iron
Calibration Software and follow the on screen prompts to completion. This is used for
magnetometer field calibration.
4. Select Install Inertial Drivers to install the hardware drivers required for operating the
sensors, and follow the on screen prompts to completion.
5. Install Inertial Manuals, if desired, and reboot the host computer.
Figure 4 - Software Installation Menu

3DM-GX4-45™Inertial Navigation System User Manual Basic Setup and Operations
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3.2 System Connections
Power is applied to the sensor either through a host computer
USB port or an external power supply, such as the one
provided in the RS232 starter kit. Use only power supplies
within the operating range of the sensor or damage or injury
could result. Once power is applied the sensor is on and active
(see Specifications on page 71).
To acquire sensor data the following components are needed: 3DM- GX4 - 45 ™sensor,
communication adapter and cable, power cable (as applicable for RS232 communications),
GPS antenna, GPS antenna adapter cable, and a host computer with access to the data
acquisition software, such as LORD MicroStrain®MIP™Monitor.
Figure 5 - System Connections

3DM-GX4-45™Inertial Navigation System User Manual Basic Setup and Operations
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3.3 Software Interface
The MIP™Monitor software includes a main window with system information and menus, a
device settings window ( see Sensor Settings on page 16 ), and several data monitoring
windows (see Data Monitoring and Recording on page 19).
The main window provides an overview of connected devices. Devices are selected by clicking
on them. A device menu is available by right clicking on the device name, and includes the most
used items from the header row menus ( Figure 6 - Main Window ). The header row menu
includes selections for data sampling, recording, device settings, opening windows, selecting
which open window to view, and advanced features such as selecting the communications
mode. The icon toolbar includes buttons for help menu access, device refresh, and data
sampling and recording (see Data Monitoring and Recording on page 19).
Figure 6 - Main Window
3.3.1 Interactive Help Menu
MIP™Monitor also features context-sensitive help menus that provide explanations of the
information and settings as they are hovered over with the computer cursor. This feature is
enabled by selecting the question mark icon or Help button in any window.
Figure 7 - Context Sensitive Help Menu

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3.4 Sensor Communication
Once power has been applied to the sensor, it is on. The sensor selects the appropriate serial
communication (USB or RS232) on power- up based on which cable is connected. If the
hardware drivers have been installed, communication can be established using the
MIP™Monitor software interface.
1. Verify the sensor device status indicator is on. GPS lock is not required to establish
sensor communication.
2. Open the MIP™Monitor software.
3. The sensor should appear in the device list automatically when the software is
opened, and includes the device information and communication port assignment
(Figure 8 - Sensor Communication ). If it is not automatically discovered, use the
refresh button to search for the sensor.
Figure 8 - Sensor Communication
NOTE
If data is not actively being exchanged between the sensor and host computer
the status message may display Not Connected. This indicates the port status,
not the sensor availability. When commands are sent to the sensor, the
software will automatically connect to it before sending the message.

3DM-GX4-45™Inertial Navigation System User Manual Basic Setup and Operations
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3.5 GPS Link
NOTE
The GPS antenna requires unobstructed line of sight with the sky in order to
achieve communication with the GPS satellites.
Communication between the GPS receiver and GPS satellites is initiated when the 3DM-GX4-
45™is first powered on. The status indicator on the device will blink differently to show if a
satellite link has been established (see Interface and Indicators on page 10). The receiver will
continuously search for satellites until a link is established. When the link is established the GPS
Monitor window in the MIP™Monitor software will display the satellite and link statistics (see
Global Positioning System (GPS) Outputs on page 26).
Communication with the satellites is required for proper sensor operation, although some
measurement outputs will be available without them.
3.6 Sensor Settings
Device settings are stored in the sensor memory. Only the configuration options that are
available for the type of sensor being used will be available in the configuration menus.
To enter the settings menu, right-click on the sensor name, and select Device Settings from the
menu (Figure 9 - Device Settings Menu).
NOTE
When selecting sensor and estimation outputs to be recorded, communications
bandwidth considerations should be taken into account, especially when using
RS232 communications. Lower baud rates equate to lower communications
bandwidth which can be consumed quickly by selecting a large number of
measurements at high sample rates. Overrunning the communications
bandwidth will result in dropped communications packets and lost data.

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1. The following describes the Device Settings interface:
a. Main menu tabs: The main tabs break up the setting into broad
functional groups for the types of measurement available. For the 3DM-
GX4-45™these will include calculated measurements (Estimation Filter),
GPS metrics (GPS), and direct inertial sensor measurements (IMU).
b. Message Format (first sub-menu tab): Under each main menu tab
there are additional sub-menu tabs, including the Message Format tab.
The Message Format tabs allows the user to select the measurement type
to be displayed and recorded (b1), and the data rate (rate at which data is
sent to the host computer) in samples/second (b2).
c. Measurement parameters (other sub- menu tabs): Available sub-
menu tabs besides the Message Format tab depend on the selected main
menu tab. These tabs include the configurable settings for each
measurements.
d. Scrolling: used to navigate to additional sub-menus.
e. Help menu: Enable the context sensitive help menu for explanations of
specific settings (see Interactive Help Menu on page 14).
Figure 9 - Device Settings Menu

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3.6.1 Saving Configurations
Sensor settings are saved temporarily by selecting the OK button in the Device Setup
window after configuration, but are lost when the device is powered off. To save current
settings in the device memory for future use, the Save Current Settings feature is used.
First adjust the sensor settings to the desired values. Next select Settings > Save Current
Settings from the main window (Figure 10 - Save Sensor Settings). The setting will now
remain intact when the sensor is powered off and then on again.
To recall the last saved settings select Settings > Load Startup Settings, and to revert the
settings back to the factory defaults, select Settings > Load Default Settings.
For some applications, it is also possible to set the device up to stream data when the device
is powered on (see Sampling on Start-up on page 57).
Figure 10 - Save Sensor Settings

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3.7 Data Monitoring and Recording
NOTE
During viewing and recording, only the outputs that are selected in the
Message Format tabs in the Device Setup menu are displayed and recorded
(see Sensor Settings on page 16).
Throughout the MIP ™Monitor menus the same icons are used to control data streaming
(sampling) and recording, shown in Table 3 - Sampling and Recording Controls. These icons
can be found in the MIP™Monitor main window icon toolbar and in each data monitoring
window. The same commands are also found in the main window Control menu.
Figure 11 - Main Window Controls
Icon Command
Run: start data streaming
Stop: end data streaming
Step: sample single set of data
Record: start and stop data recording
Table 3 - Sampling and Recording Controls

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There are several data monitoring views available depending on what measurements are
desired for monitoring and recording. Each view corresponds to one of the main categories in
the Device Settings window. For example, the 3DM - GX4 - 45 ™includes Sensor Data
Monitoring for the IMU measurements, GPS Monitoring for the GPS metrics, and
EFMonitoring for the Estimation Filter outputs (Figure 12 - Data Monitoring and Streaming ).
During viewing and recording only the outputs that are selected in the Message Format tab of
the Device Settings menu are displayed and recorded (see Sensor Settings on page 16).
Data streaming must be started before data can be recorded, however it is not necessary to be
viewing it in a data monitoring window. Data monitoring is used primarily to confirm the system
is operating correctly or to view the outputs in near real time. If sensor setup has already been
confirmed, streaming and recording can be initiated from the main window.
Figure 12 - Data Monitoring and Streaming is an example of Sensor Data Monitoring, which
displays the selected IMU measurements. In data monitoring windows, no data will be
displayed until data streaming is started, and no data will be recorded (even if it is being viewed)
until data recording is initiated (armed). In this example, the y-axis of the graph indicates data
points and the x-axis is the measurement units, and there is a tab for each measurement.
1. Right-click on the device in the main window and select SensorData Monitoring.
2. Press the Start Streaming icon to start sampling.
Figure 12 - Data Monitoring and Streaming