3DM-GX3-45

NEW VERSION

There is a new version of this product available. The product on this page has been discontinued and the datasheet and manual are provided for informational purposes.

Product no longer stocked – limited availability
Contact for pricing and lead time--a minimum order quantity may apply

The 3DM-GX3® -45 high-performance, miniature GPS-Aided Inertial Navigation System (GPS/INS) combines MEMS inertial sensors, a highly-sensitive embedded GPS receiver, and a complex Extended Kalman Filter to generate optimal position, velocity, and attitude (PVA) estimates. This combination of technologies creates better short-term GPS-out performance, sustained-G attitude performance, and provides higher rate PVA data than typical GPS and AHRS sensors. Raw GPS data, IMU data, and filtered INS data are time-aligned and available as user-defined packets (either by polling or continuous stream).

Product no longer stocked – limited availability

Contact for pricing and lead time--a minimum order quantity may apply

Datasheet Manual

Where to Buy?
U.S. International OEM

Contact Sales for volume pricing

Best in Class

precise position, velocity and attitude estimations
high-speed sample rate & flexible data outputs
high performance under vibration and high-g

Easiest to Use

smallest, lightest industrial GPS/INS available
simple integration supported by SDK and comprehensive API

Cost Effective

reduced cost and rapid time to market for customer’s applications
aggressive volume discount schedule

Product no longer stocked – limited availability Contact for pricing and lead time--a minimum order quantity may apply

Navigation Specifications

Kalman Filter Performance

Typical position accuracy †

±2.5 m RMS horizontal, ±5 m RMS vertical

Typical velocity accuracy †

±0.1 m/s to ±0.75 m/s RMS (application and settings dependent)

Typical attitude accuracy †

±0.35 deg RMS roll & pitch

±1.0 deg RMS heading

Update rate

100 Hz

Features

vehicle dynamics mode selection (portable/automotive/airborne)
user-defined sensor to vehicle frame transformation
antenna offset specification, bias enable/disable
internal magnetometer enable/disable and external GPS and heading sensor support
full world magnetic model

Data output rate

up to 1000 Hz

AHRS Specifications

Attitude and Heading

Attitude heading range

360° about all 3 axes

Accelerometer range

±5g standard

Gyroscope range

±300°/sec standard

Static accuracy

±0.5° pitch, roll, heading typical for static test conditions

Dynamic accuracy

±2.0° pitch, roll, heading for dynamic (cyclic) test conditions and for arbitrary angles

Long term drift

eliminated by complimentary filter architecture

Repeatability

0.2°

Resolution

<0.1°

Data output rate

1 Hz to 100 Hz

Filtering

sensors sampled at 30 kHz, digitally filtered (user adjustable ) and scaled into physical units; coning and sculling integrals computed at 1 kHz

Output modes

acceleration, angular rate, magnetic field, deltaTheta, deltaVelocity, Euler angles, orientation matrix, quaternion, LLH position, NED velocity, GPS time, filter status, PVA estimate, PVA uncertainties, attitude as: quaternion, matrix, or Euler angles, gravity-free linear acceleration, bias-compensated angular rate

General

A/D resolution

16 bits SAR oversampled to 17 bits

Interface options

USB 2.0 or RS232

Baud rate

9,600 bps to 921,600 bps

Power supply voltage

+3.2 to +16 volts DC

Power consumption

at full performance with GPS lock:
200 mA typ (250 mA max) when powered by Vpri (3.2V-5.5V);
850 mW typ (1.0W max) when powered by Vaux (5.2V-16V)

Connector

micro-DB9

Operating temperature

-40 °C to +65 °C

Dimensions

44 mm x 24 mm x 14 mm - excluding mounting tabs, width across tabs 37 mm

Weight

23 grams

ROHS

compliant

Shock limit

500 g

Software utility

CD in starter kit (XP/Vista/Win7/Win 8 compatible)

Software development kit (SDK)

complete data communications protocol and sample code

compliant

Sensor Specifications

Accels

Gyros

Mags

Measurement range

±5 g

±300°/sec

±2.5 Gauss

Non-linearity

±0.1 % fs

±0.03 % fs

±0.4 % fs

In-run bias stability

±0.04 mg

18°/hr

—

Initial bias error

±0.002 g

±0.25°/sec

±0.003 Gauss

Scale factor stability

±0.05 %

±0.1 %

Noise density

80 µg/√Hz

0.03°/sec/√Hz

100 µGauss/√Hz

Alignment error

±0.05°

User adjustable bandwidth

225 Hz max

440 Hz max

230 Hz max

Sampling rate

30 kHz

7.5 kHz max

GPS Specifications

GPS Receiver

GPS receiver type

50-channel u-blox 6 engine GPS L1 C/A code SBAS: WAAS, EGNOS, MSAS

Data output rate

1 Hz to 4 Hz

Time-to-First-Fix

Cold starts: 27 sec

Aided starts: 4 sec

Hot starts: 1 sec

GPS tacking and navigation sensitivity

-159 dBm

Sensitivity

Tracking: -159 dBm

Cold starts: -147 dBm

Hot starts: -158 dBm

GPS velocity accuracy

0.1 m/sec

GPS heading accuracy

0.5°

GPS horizontal position accuracy

position: 2.5 m CEP

SBAS: 2.0 m CEP

GPS timepulse signal accuracy

30 nsec RMS

< 60 nsec 99%

GPS acceleration limit

≤ 4 g

GPS altitude limit

no limit

GPS velocity limit

500 m/sec (972 knots)

GPS antenna connector

MMCX type

Options

Accelerometer range

±1.7 g, ±16 g, ±50 g

Gyroscope range

±50°/sec, ±600°/sec, ±1200°/sec

† RMS values generated from actual vehicle testing (airborne & land) when compared to a reference navigation unit

General Documentation

Technical Notes

Mechanical Prints (Uncontrolled)

FAQ's

3DM-GX3® -45 FAQ's

Video

Firmware Upgrade

Firmware Upgrades for 3DM-GX3®

Software Download

MIP Software Downloads

Software Development Kit

How do I set the 3DM-GX3 back to its default settings?

Using MIP Monitor software, to reset the device to the factory defaults:

Establish communication as normal with the sensor.
Click Settings.
Click Load Default Settings and a message box pops up.
Click OK and the message box disappears.
Click Settings again.
Click Save Current Settings and a message box pops up.
Click OK and the message box disappears.

This process does not erase any hard and soft iron calibration that may be on the device.

The Hard and Soft Iron Cal software we provide must be used to do that.

How do I write previously saved hard and soft iron calibration coefficients back to my 3DM-GX3?

Our MIP Monitor software, as written, will not allow you to save the 12 hard and soft iron calibration coefficients to a file, and then read that file back into the software to rewrite the values to the inertial sensor.

However, you cand accomplish the task by recording the values that are displayed (or take a screen grab).

This would be followed by using the data communications protocol EEPROM Write command to write the values back into the device.

This would require either a terminal program or the ability to write software, an understanding of how to construct the command packets, and a list of the EEPROM addresses involved.

Please contact your Lord MicroStrain support engineer for further details.

What is the difference between the Internal and External GPS selector in MIP Monitor software?

The Internal or External GPS selector refers to the function that allows the user to turn off the on-board GPS and use a computer to send GPS updates to the device.

If you are using the internal GPS, always select ‘Internal’.

Refer to the data communications protocol if you intend to supply external GPS.

MIP Monitor software also has a test function that allows you to input user selected GPS parameters.

How will the 3DM-GX3-35 work with the magnetometers turned off?

Without the magnetometer, the only heading reference is from the GPS and this heading reference can only be used on a platform that has some constant lateral motion. This is the only way GPS can get a good heading. Once a heading reference is obtained (either magnetometer or GPS heading) it can be maintained for a short time (less than 30 seconds typically) with just the gyroscopes. This, of course, would have to be done through a fusion filter external to the -35. The LORD MicroStrain 3DM-GX3-45 product actually has this functionality built-in.

What is the difference between SINGLE BYTE and MIP protocol?

The main difference between single byte (SB) and MIP is as follows:

All MIP commands and data have a header and checksum. SB only has a header (the echo of the command byte) and a checksum on the replies. This means that the programmer has to create a header and calculate the checksum for a command before s/he sends the command. This was not necessary with SB.
MIP setup and control commands (like start and stop continuous mode) send an ACK/NACK field with a reply. SB does not. The ACK/NACK field has an error code that can be used to confirm that a command was accepted.
MIP packets can contain multiple command and data fields. SB commands and data only have one fixed field.

The reason we created MIP was the higher reliability for communications and control, plus the ability to have custom data messages. SB was prone to phantom commands in a noisy environment. In addition, SB had a limited number of data combinations available.

To move code from Single Byte to MIP with simple applications is fairly painless if you follow some guidelines.

You can “prebuild” all your setup and control commands and make them constants in your code. You can plug the prebuilt packet constants into the same part of the code that you previously used to send a single byte command (In essence, you are sending a “multi-byte” command instead of a single byte command). We have a “packet builder” tool in the MIP Monitor that will build the packet for you. You can try out the command and then copy the packet and paste it directly into your code as a string constant.
When you design the MIP data message, make sure all the “data rate decimation” values are the same. This will make all the data packets identical, which makes finding data in the packet similar to finding data in a SB data message (by using fixed offsets).

What is the impedance on the GPS connector?

The impedance on the GPS connector is 50 ohms.

The 3DM-GX3 provides 3 volts power on the center pin of the connector (active antenna).

What is the ECCN for the 3DM-GX3?

The ECCN is 7A994.

How do I upgrade the firmware on my GX3 inertial sensor?

From time to time, MicroStrain releases firmware upgrades for its 3DM-GX3® inertial sensors. These firmware upgrades represent operating improvements, new functions, etc. In most cases, the user may download these upgrades and perform the upgrade using a simple step-by-step process. This technical note describes which firmware upgrades may be accomplished by the user and which firmware upgrades must be done at the factory. Familiarity with 3DM-GX3® operation is assumed. The upgrade procedure employs a Microsoft Windows computer and the Microsoft HyperTerminal utility.

Click here.

Can I use the 3DM-GX3-45 with Bluetooth?

The LORD MicroStrain 3DM-GX3-45 high-performance, miniature GPS-Aided Inertial Navigation System (GPS/INS) combines MEMS inertial sensors, a highly-sensitive embedded GPS receiver, and a complex Extended Kalman Filter to generate optimal position, velocity, and attitude (PVA) estimates. It is currently available with RS-232 and USB communication interfaces. A wireless communication interface can easily be added by employing off-the-shelf Bluetooth RS-232 adapters.

Click here.

Can I use dataloggers with the inertial sensors?

Many inertial applications incorporate dataloggers. The datalogger can take many forms: hardware or software, analog or digital, simple or complex, and/or combinations of all. For our purposes, let’s work through a simple-digital-software datalogger. In this case, datalogger software is installed on a computer. The inertial sensor is connected to the computer via an RS-232 communication interface. The inertial sensor is pre-programmed to automatically send data when powered. The computer receives the stream of data and the datalogger software continuously records the stream to a data file.

Click here.

How can I program the inertial sensor so that it outputs on start-up?

The LORD MicroStrain 3DM-GX3 inertial sensor family allows the user to pre-program the inertial sensor so that it continuously outputs specific data packets at specific sampling rates each time it is powered on. This functionality facilitates integration of the inertial sensor with other equipment and systems. For example, connection of the 3DM-GX3 inertial sensor to a datalogger becomes quite easy. The user pre-programs the 3DM-GX3 data output settings on his desktop, connects the 3DM-GX3® to the datalogger’s RS-232 port, powers the 3DM-GX3, and the datalogger records the inertial data. This technical note assumes some familiarity with your particular 3DM-GX3 inertial sensor and its accompanying MIP Monitor (Windows-based) software.

Click here.

How can I get NMEA data packets from the inertial sensor?

NMEA packets can be had by putting the 3DM-GX3-35 or 3DM-GX3-45 in GPS Direct mode and manipulating the devices with the GPS manufacturer’s software.

Here are two technical notes which show how this is done:

http://files.microstrain.com/8401-0017-Using-u-blox-Software-3DM-GX3-35-3DM-GX3-45.pdf

http://files.microstrain.com/8401-0013-Outputting-NMEA-Packets-to-GPS-Ready-Software.pdf

NMEA packets can also be generated in the user's own application by gathering the navigation data output by the 3DM-GX3-35 or 3DM-GX3-45 and formatting it into NMEA packets. The inertial sensor feeds navigation data to the host computer, the host computer formats the navigation data into NMEA packets, and sends them out the serial port to a NMEA-ready device.

How long is the cable for the GPS antenna?

The GPS antenna cable that ships with every 3DM-GX3-35 and 3DM-GX3-45 is 3 meters in length.

Cable length is important. The longer the cable, the lower the signal strength. If the user lengthens the cable, the signal strength will diminish. The loss of signal strength can only be empirically determined by trying out a particular installation. Loss of signal strength will manifest itself in the number of satellites seen, quality of data reception from satellites, etc.

Does the GPS receiver use Differential GPS?

No. The GPS Receiver only receives standard GPS signals. It does not receive Differential GPS (DGPS) signals. If the user requires DGPS input, the GX3 will accept DGPS via an external feed and in the case of the 3DM-GX3-45, incorporate it in its Kalman filter processing. To be clear: the on-board GPS will be bypassed in favor of the external GPS.

Wikipedia GPS: http://en.wikipedia.org/wiki/Global_Positioning_System

Wikipedia DGPS: http://en.wikipedia.org/wiki/Differential_GPS

Can the 3DM-GX3-45 be coupled with RTK?

No, the on-board GPS does not support this.... but if the user has a GPS that does, this external GPS can input its 'RTK-groomed' measurements into the 3DM-GX3-45 and the 3DM-GX3-45 will incorporate those measurements into the Kalman filter. To be clear: the on-board GPS will be bypassed in favor of the external GPS.

Wikipedia's definition: http://en.wikipedia.org/wiki/Real_Time_Kinematic

Real Time Kinematic (RTK) satellite navigation is a technique used to enhance the precision of position data derived from satellite-based positioning systems, being usable in conjunction with GPS, GLONASS and/or Galileo. It uses measurements of the phase of the signal′s carrier wave, rather than the information content of the signal, and relies on a single reference station to provide real-time corrections, providing up to centimetre-level accuracy. With reference to GPS in particular, the system is commonly referred to as Carrier-Phase Enhancement, or CPGPS. It has application in land survey and in hydrographic survey.

How does the 3DM-GX3-45 work?

Here is a link to the 3DM-GX3-45 Theory of Operation: http://files.microstrain.com/3DM-GX3-45_Theory_of_Operation.pdf

What is the 3DM-GX3-45 accuracy?

Kalman Filter Performance

Typical position accuracy †

±2.5 m RMS horizontal, ±5 m RMS vertical

Typical velocity accuracy †

±0.1 m/s to ±0.75 m/s RMS (application and settings dependent)

Typical attitude accuracy †

±0.35 deg RMS roll &

† RMS values generated from actual vehicle testing (airborne & land) when compared to a reference navigation unit

Attitude and Heading (AHRS)

Static accuracy

±0.5° pitch, roll, heading typical for static test conditions

Dynamic accuracy

±2.0° pitch, roll, heading for dynamic (cyclic) test conditions and for arbitrary angles

GPS Receiver

GPS velocity accuracy

0.1 m/sec

GPS heading accuracy

0.5°

GPS horizontal position accuracy

< 2.5 m Autonomous

< 2.0 m SBAS (CEP, stationary 24 hours, SEP 3.5 m)

GPS timepulse signal accuracy

30 nsec RMS

< 60 nsec 99%

Can the 3DM-GX3-45 generate a data file for Precise Point Positioning (PPP) – post GPS processing?

In a word, no. Precise Point Positioning is a Global Navigation Satellite System (GNSS) positioning method to calculate very precise positions up to few centimeter level using a single (GNSS) receiver in a dynamic and global reference framework like International Terrestrial Frame (ITRF). The 3DM-GX3-45 is not capable of this precision.

What formulas are used to convert between the various orientation data quantities?

Here is a link to a detailed technical note: http://files.microstrain.com/Orientation%20Conversion%20formulas.pdf

Is it possible to use the RS-232 interface of LORD MicroStrain® inertial sensors with a serial port emulator (i.e., with a USB to serial adapter)?

Yes. We have had good success with several types of off-the-shelf USB to serial port adaptors, such as those from IOGear and Keyspan, which may be purchased through any of the electronics products distributors.

Can the USB and serial interfaces of the 3DM-GX3 be used at the same time?

No – only one can be used at a time. The device auto-senses which communication signal is attached (USB or serial), and only uses that channel for communications.

Where can I buy additional communication 3DM-GX3 and 3DM-GX3 OEM interface connectors?

The standard unit uses a specialized Ulti-Mate brand micro-DB9. This technical note contains more details: http://files.microstrain.com/TN-I0023_Inertia-Link_3DM-GX2_3DM-GX3_Pin-Outs.pdf

The OEM unit uses a Samtec FTSH-105-01-F-D-K. This technical note contains more details: http://files.microstrain.com/3DM-GX3-25_OEM_Footprint_and_Connector.pdf

LORD MicroStrain^® suggests that you purchase additional connectors with your order.

How long can the communication cables be for the 3DM-GX3?

The 3DM-GX3 USB and RS-232 communication interfaces are built to satisfy the standard USB-IF and EIA specifications. LORD MicroStrain^® provides 6 foot cables as standard. Many techniques can be used to extend the length of the communication interfaces including powered USB hubs, USB boosters, RS-232 extenders, etc.

What is the purpose of the double mounting holes on the 3DM-GX3 standard enclosure?

The 3DM-GX3 standard enclosure has been designed with precision alignment holes on the ‘ears’ of the enclosure to allow the user to install the unit with precise alignment to the rest of the components in the user’s application.

Does the 3DM-GX3 require calibration during use?

The 3DM-GX3 is calibrated at the factory. The user is also provided with Hard and Soft Iron Calibration software to field calibrate the GX3 in situ. This video further describes the function: http://www.microstrain.com/video/hard-soft-iron-calibration

Important note: Hard and soft iron calibration is not required for the 3DM-GX3-15 and the 3DM-GX315 OEM. These units do not contain magnetometers.

From time to time the 3DM-GX3 may need recalibration. For example, as a result of coming in contact with magnetic influences (magnets, motors, etc.), residual magnetism may be picked up by the on-board components which will alter the calibration. Another example: the 3DM-GX3 receives a severe shock, slightly altering the position of the circuit boards in relation to the enclosure, again altering the calibration. In these cases the unit should be returned to the factory for recalibration.

Does the 3DM-GX3 have an analog out option?

No.

Can I use multiple 3DM-GX3 at the same time?

Yes. Any number of units can be operated by a host at the same time. Several considerations surround this implementation (primarily computing power) and we suggest that you discuss your requirements with LORD MicroStrain^® sales or a support engineer.

What are the power requirements of the 3DM-GX3?

For the standard units, here is a link to a detailed technical note: http://files.microstrain.com/TN-I0023_Inertia-Link_3DM-GX2_3DM-GX3_Pin-Outs.pdf

For the OEM units, here is a link to a detailed technical note: http://files.microstrain.com/3DM-GX3-25_OEM_Footprint_and_Connector.pdf

Can the 3DM-GX3 be installed in any orientation?

Yes, there are no limitations. However, if a user requires a ‘zeroing’ of the axes, this must be done in the user’s external application. Good practice dictates that the orientation matrix be used to calculate such zeroing. Please also be aware of the mathematical singularity in Euler angles.

The user should be aware that the Euler angle formulation in general contains a mathematical singularity at Pitch = +90 or –90 degrees. In practice, poor numerical results will be present if the Pitch angle exceeds +/-70 degrees. In applications where the Pitch angle cannot be guaranteed to exceed these values, it is recommended that the orientation matrix output be utilized instead.

Are the 3DM-GX3 sampling rates adjustable?

Yes. The sampling rates are user adjustable.

For the -15 and -25, the user may set the sampling rate at up to 1000 Hz depending on the data quantity.

For the -35, the user may set the AHRS sampling rate up to 1000 Hz depending on the data quantity and the GPS sampling rate up to 4 Hz.

For the -45, the user may set the Navigation sampling rate up to 100 Hz.

At what baud rates can the 3DM-GX3 be operated?

The baud rate is user adjustable and may be set to 9600, 19200, 115200 (default), 230400, 460800, and 921600.

Can distortions of Earth’s magnetic field degrade the system accuracy of the 3DM-GX3?

Yes. The presence of strong magnetic fields or large magnetic materials will distort Earth’s weak local magnetic field and this will influence the on-board magnetometers. A hard and soft iron calibration software utility is provided to field calibrate the 3DM-GX3-25, 3DM-GX3-25 OEM, 3DM-GX3-35 and 3DM-GX3-45.

The 3DM-GX3-15 and 3DM-GX3-15 OEM do not contain magnetometers and are not affected by hard and/or soft iron interference.

What orientation output formats are available with the 3DM-GX3?

The following orientation outputs formats are available:

Acceleration
Angular Rate
Magnetic Vector
DeltaAngle and DeltaVelocity
Orientation Matrix
Quaternion
Euler Angles (pitch, roll and yaw)
...and more.

A detailed description of these outputs can be found in the Data Communications Protocol manual of each product.

What communication interfaces are available for the 3DM-GX3?

The standard units support both USB and RS-232 interface.

The OEM units support both USB and TTL.

May I write my own software application for the 3DM-GX3?

Yes. We provide a complete data communications protocol manual which describes in detail each and every command and response that is available with the device. Applications may be developed in any programming environment (C, VB, LabVIEW, Linux, Matlab, etc.) which supports serial communication.

What software do you provide for 3DM-GX3?

We provide a general application for Microsoft XP/Vista/Win 7 operating systems that configures, reads, displays and saves data generated by the device. This application (MIP Monitor) supports both the USB and RS-232 communication interfaces.

How is the 3DM-GX3 packaged?

When you initially purchase a 3DM-GX3, a starter kit (SK) provides you with everything you need to get started! SKs include a 3DM-GX3 module, communication and power cables, software, manuals and GPS antenna if applicable. In subsequent purchases you may only require additional modules or other individual components. Several communication interfaces are available creating several starter kit variations.

Can the user retrieve the current GPS almanac from the 3DM-GX3-45 via USB or RS-232?

Yes, but the method is a bit involved. The user would have to put the -45 in direct mode to the GPS, use the u-blox commands to retrieve the almanac, and put the -45 back into normal mode for regular use.

Can you characterize the 3DM-GX3-45 horizontal position accuracy?

The GPS datasheet accuracy is CEP at 24 hours stationary, a common test condition for GPS. CEP is a 50% confidence number. Like other single (non-differential) GPS units, our accuracy is limited by constellation geometry, atmospheric, and clock error effects (largest contributors when selective availability is not included.) This pegs best performance at approximately 5 meters RMS dynamic. This is improved for areas where WAAS is enabled.

Can you quantify the 3DM-GX3-45 positional vertical accuracy?

We have not performed extended duration tests against a surveyed point, but have tested against a higher-performing unit (with tightly-coupled filter.) Dynamic RMS position error during car and flight tests for the vertical channel, hover around 5m, with individual excursions out to about 10m. Telling which unit was more accurate at a given time, and at which extreme of the uncertainty ellipse each is at, is more difficult.