PNI TRAX2 AHRS User manual

TRAX2 AHRS & DIGITAL COMPASS
USER MANUAL
Release Date: August 11, 2021

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Table of Contents
1COPYRIGHT & WARRANTY INFORMATION ................................................. 1
2INTRODUCTION ......................................................................................... 2
3SPECIFICATIONS......................................................................................... 3
3.1 Characteristics & Requirements ........................................................... 3
3.2 Mechanical Drawings............................................................................ 7
4SET-UP....................................................................................................... 8
4.1 Electrical Connections........................................................................... 8
4.2 Installation Location.............................................................................. 9
4.2.1 Operate within the TRAX2’s dynamic range................................ 9
4.2.2 Locate away from changing magnetic fields ............................... 9
4.2.3 Mount in a physically stable location .......................................... 9
4.3 Mechanical Mounting........................................................................... 9
4.3.1 Pitch and Roll Convention.......................................................... 10
4.3.2 Coordinate System..................................................................... 10
4.3.3 Mounting Orientation................................................................ 10
5USER CALIBRATION.................................................................................. 12
5.1 Magnetic Calibration........................................................................... 12
5.1.1 Full-Range Calibration................................................................ 15
5.1.2 Limited-Tilt Calibration .............................................................. 17
5.1.3 Hard-Iron-Only Calibration ........................................................ 19
5.2 Accelerometer Calibration.................................................................. 19
6OPERATION WITH TRAX STUDIO .............................................................. 21
6.1 Installation .......................................................................................... 21
6.2 TRAX Studio Header and Connecting to TRAX Studio ........................ 21
6.3 TRAX Studio Footer and Saving/Applying Settings ............................. 22
6.4 Configuration Tab ............................................................................... 23
6.4.1 General Settings......................................................................... 24
6.4.2 Acquisition Settings.................................................................... 25
6.5 Calibration and the Calibration Tab.................................................... 26
6.5.1 Calibration Settings.................................................................... 26
6.5.2 Performing a Calibration............................................................ 28
6.5.3 Calibration Results ..................................................................... 29
6.6 Test Tab............................................................................................... 30
6.7 Log Data Tab ....................................................................................... 34
6.8 Graph Tab............................................................................................ 35
6.9 System Log Tab ................................................................................... 36
7OPERATION WITH PNI BINARY PROTOCOL ............................................... 37
7.1 Datagram Structure ............................................................................ 37
7.2 Parameter Formats............................................................................. 38

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7.2.1 Endianness ................................................................................. 38
7.2.2 Floating Point ............................................................................. 38
7.2.3 Signed Integer............................................................................ 39
7.2.4 Unsigned Integer........................................................................ 40
7.2.5 Boolean ...................................................................................... 40
7.3 Commands Overview.......................................................................... 41
7.4 Set-Up Commands .............................................................................. 42
7.4.1 Module Information................................................................... 42
7.4.2 Module Configuration................................................................ 43
7.4.3 Saving Settings ........................................................................... 50
7.5 Measurement Commands .................................................................. 50
7.5.1 Setting the Reference Magnetic Field Criteria........................... 50
7.5.2 Data Acquisition Parameters ..................................................... 51
7.5.3 Data Components ...................................................................... 52
7.5.4 Making a Measurement............................................................. 54
7.5.5 Continuous Data Output After Power Cycle.............................. 55
7.6 Calibration Commands........................................................................ 56
7.6.1 User Calibration Commands ...................................................... 56
7.6.2 Performing a User calibration.................................................... 58
7.6.3 Calibration Score........................................................................ 58
7.6.4 Factory Calibration..................................................................... 59
7.7 Compass Mode Commands ................................................................ 60
7.7.1 Switching Functional Mode ....................................................... 60
7.7.2 FIR Filters.................................................................................... 61
7.7.3 Power Down/Up ........................................................................ 63
7.8 Using Multiple Coefficient Sets........................................................... 64
7.9 Communication Protocol Example ..................................................... 67
APPENDIX –SAMPLE CODE............................................................................ 68

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List of Figures
Figure 3-1: Typical Current Drawing During Application of External Power .......... 5
Figure 3-2: TRAX2 PCA Mechanical Drawing .......................................................... 7
Figure 3-3: Molex-to-Pigtail Cable Drawing, pn 14476........................................... 7
Figure 3-4: Molex-to-USB Cable Drawing, pn 14467 .............................................. 7
Figure 4-1: Positive & Negative Roll and Pitch Definition..................................... 10
Figure 4-2: TRAX2 Enclosed Mounting Orientations ............................................ 11
Figure 5-1: 12 Point Full-Range Calibration (Realistic View) ................................ 16
Figure 7-1: Datagram Structure ............................................................................ 37
List of Tables
Table 3-1: Performance Specifications1.................................................................. 3
Table 3-2: Absolute Maximum Ratings................................................................... 4
Table 3-3: Electrical Requirements......................................................................... 4
Table 3-4: I/O Characteristics.................................................................................. 5
Table 3-5: Environmental Requirements................................................................ 5
Table 3-6: Mechanical Characteristics.................................................................... 6
Table 4-1: TRAX2 Pin Descriptions.......................................................................... 8
Table 5-1: Magnetic Calibration Mode Summary................................................. 14
Table 5-2: 12 Point Full-Range Calibration Pattern .............................................. 15
Table 5-3: 12 Point 2D Calibration Pattern........................................................... 17
Table 5-4: 12 Point Limited-Tilt Calibration Pattern............................................. 18
Table 5-5: 12 Point Limited-Tilt Calibration Alternative Pattern.......................... 18
Table 5-5: 6 Point Hard-Iron-Only Calibration Pattern......................................... 19
Table 7-1: Port Configuration ............................................................................... 37
Table 7-2: TRAX2 Command Set ........................................................................... 41
Table 7-3: Configuration Identifiers...................................................................... 44
Table 7-4: Sample Points....................................................................................... 45
Table 7-5: Merge Rate Identifiers......................................................................... 49
Table 7-6: Component Identifiers......................................................................... 52
Table 7-7: Recommended FIR Filter Tap Values................................................... 62
Table 7-8: Multiple Coefficient Command List ..................................................... 65

1 Copyright & Warranty Information
© Copyright PNI Sensor, Protonex LLC 2019. Revised December 2018.
All Rights Reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except
as allowed under copyright laws. For the most recent version of this manual, visit our website at
www.pnicorp.com.
PNI Sensor
2331 Circadian Way
Santa Rosa, CA 95407, USA
Tel: [phone]
Warranty and Limitation of Liability. PNI Sensor ("PNI") manufactures its TRAX2 products (“Products”) from parts
and components that are new or equivalent to new in performance. PNI warrants that each Product to be
delivered hereunder, if properly used, will, for one year following the date of shipment unless a different warranty
time period for such Product is specified: (i) in PNI’s Price List in effect at time of order acceptance; or (ii) on PNI’s
web site (www.pnicorp.com) at time of order acceptance, be free from defects in material and workmanship and
will operate in accordance with PNI’s published specifications and documentation for the Product in effect at time
of order. PNI will make no changes to the specifications or manufacturing processes that affect form, fit, or
function of the Product without written notice to the OEM, however, PNI may at any time, without such notice,
make minor changes to specifications or manufacturing processes that do not affect the form, fit, or function of
the Product. This warranty will be void if the Products’ serial number, or other identification marks have been
defaced, damaged, or removed. This warranty does not cover wear and tear due to normal use, or damage to the
Product as the result of improper usage, neglect of care, alteration, accident, or unauthorized repair.
THE ABOVE WARRANTY IS IN LIEU OF ANY OTHER WARRANTY, WHETHER EXPRESS, IMPLIED, OR STATUTORY,
INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR ANY PARTICULAR
PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE. PNI
NEITHER ASSUMES NOR AUTHORIZES ANY PERSON TO ASSUME FOR IT ANY OTHER LIABILITY.
If any Product furnished hereunder fails to conform to the above warranty, OEM’s sole and exclusive remedy and
PNI’s sole and exclusive liability will be, at PNI’s option, to repair, replace, or credit OEM’s account with an amount
equal to the price paid for any such Product which fails during the applicable warranty period provided that (i)
OEM promptly notifies PNI in writing that such Product is defective and furnishes an explanation of the deficiency;
(ii) such Product is returned to PNI’s service facility at OEM’s risk and expense; and (iii) PNI is satisfied that claimed
deficiencies exist and were not caused by accident, misuse, neglect, alteration, repair, improper installation, or
improper testing. If a Product is defective, transportation charges for the return of the Product to OEM within the
United States and Canada will be paid by PNI. For all other locations, the warranty excludes all costs of shipping,
customs clearance, and other related charges. PNI will have a reasonable time to make repairs or to replace the
Product or to credit OEM’s account. PNI warrants any such repaired or replacement Product to be free from
defects in material and workmanship on the same terms as the Product originally purchased.
Except for the breach of warranty remedies set forth herein, or for personal injury, PNI shall have no liability for
any indirect or speculative damages (including, but not limited to, consequential, incidental, punitive and special
damages) relating to the use of or inability to use this Product, whether arising out of contract, negligence, tort, or
under any warranty theory, or for infringement of any other party’s intellectual property rights, irrespective of
whether PNI had advance notice of the possibility of any such damages, including, but not limited to, loss of use,
revenue or profit. In no event shall PNI’s total liability for all claims regarding a Product exceed the price paid for
the Product. PNI neither assumes nor authorizes any person to assume for it any other liabilities.
Some states and provinces do not allow limitations on how long an implied warranty lasts or the exclusion or
limitation of incidental or consequential damages, so the above limitations or exclusions may not apply to you. This
warranty gives you specific legal rights and you may have other rights that vary by state or province.

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2 Introduction
Thank you for purchasing PNI’s TRAX2 Attitude & Heading Reference System (AHRS) & Digital
Compass module. The TRAX2 employs a proprietary Kalman filtering algorithm that
intelligently fuses PNI's patented Reference Magnetic Sensors with a 3-axis gyroscope and 3-
axis accelerometer. The result is an orientation device that provides accurate heading information
under a wide variety of conditions, including its ability to overcome errors normally caused by
erratic motion and/or changes in the local magnetic field. The advanced features of the TRAX2
make it ideal for a variety of applications, including:
▪Drones
▪Robotics
▪Ocean buoys
▪Unmanned ground and underwater vehicles (UGVs and UUVs)
▪Manned ground and underwater vehicles
TRAX2 combines PNI’s high sensitivity magneto-inductive sensors with a high stability 3-axis
MEMS accelerometer to provide accurate heading information under a wide variety of
conditions and the ability to overcome errors caused by changes in the local magnetic field. This
provides no drift, high accuracy heading, pitch and roll and long-term static accuracy.

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3 Specifications
3.1 Characteristics & Requirements
Table 3-1: Performance Specifications1
Parameter
Value
Compass
Mode
Heading
Static Accuracy2
0.3° rms
Resolution
0.1°
Repeatability
0.05° rms
Attitude
Range
Pitch
± 90°
Roll
± 180°
Static Accuracy
0.2° rms
Resolution
0.01°
Repeatability
0.05° rms
AHRS Mode
Heading
Accuracy3
2.0° rms
Resolution
0.1°
Attitude
Range
Pitch
± 90°
Roll
± 180°
Accuracy
2.0° rms
Resolution
0.01°
Footnotes:
1. Specifications are typical unless otherwise noted, and subject to change.
2. Assumes TRAX2 is motionless, the local magnetic field is clean relative to
user calibration, ≤65° of pitch, and after a Full-Range calibration has been
performed.
3. Assumes heading status is “1”. See Section 0 or Section 7.5.3 for a
discussion on heading status.

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Table 3-2: Absolute Maximum Ratings
Parameter
Minimum
Maximum
Units
Supply Voltage
-0.3
+10
VDC
Storage Temperature
-40
+85
°C
VIN TTL UART Rx
-0.3
4
V
VIN RS-232 Rx
-30
+30
V
CAUTION:
Stresses beyond those listed above may cause permanent damage to the device.
These are stress ratings only. Operation of the device at these or other conditions
beyond those indicated in the operational sections of the specifications is not implied.
Table 3-3: Electrical Requirements
Parameter
Value
Supply Voltage
3.7 to 8 VDC
RS-232
High Level Input
2.4 V Max, 1.6V typical
Low Level Input
0.6 V Min, 1.2V typical
Output Voltage Swing
±5.2 V typ., ±5.0 V min.
Tx Output Resistance
300 Ω
Serial UART
CMOS/TTL(1)
UART Rx(2) VIH
2.3 V Min
1.87V Min Typical(1)
UART RxVIL
0.99 V Max
1.23 V Max Typical(1)
UART Tx VOH (8mA
load)
2.9V Min
UART Tx VOL (8mA
load)
0.4V Max
Current Draw
AHRS Mode@ max.
sample rate
20 mA typical
Compass Mode @
max. sample rate
17 mA typical
During application of
external power
See Figure 3-1
Sleep Mode
0.5 mA typical
(1) CMOS 3.3V and TTL-compliant logic levels. UART RX VIH is tested at 2.3V min. and is guarenteed by
design to be 1.87V min
(2) Vin on UART Rx is rated at 4V MAX. Higher than 3.6V can cause excessive loading on source.

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Figure 3-1: Typical Current Drawing During Application of External Power
Table 3-4: I/O Characteristics
Parameter
Value
Communication Interface
RS232 and TTL-compliant
serial UART
Communication Protocol
PNI Binary
Communication Rate1
2400 to 921,600 baud
Maximum Data Output Rate
≈30 samples/sec
Footnote:
1. The TRAX2 can operate up to 921,600 baud, but native RS232 is limited
to 115,200 baud.
Table 3-5: Environmental Requirements
Parameter
Value
Operating Temperature1
-40C to +85C
Storage Temperature
-40C to +85C
Footnote:
1. To meet performance specifications across this range, recalibration will be
necessary as the temperature varies.

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Table 3-6: Mechanical Characteristics
Parameter
Value
Dimensions (l x w x h)
3.5 x 4.3 x 0.84 cm
Weight
7 gm
Connector
6-pin Molex, part number 51021-0600

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3.2 Mechanical Drawings
Figure 3-2: TRAX2 PCA Mechanical Drawing
Figure 3-3: Molex-to-Pigtail Cable Drawing, pn 14476
Figure 3-4: Molex-to-USB Cable Drawing, pn 14467
CABLE USB TO TTL (FTDI TTL-232R-3V3-WE)

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4 Set-Up
This section describes how to configure the TRAX2 in your host system. To install the TRAX2
into your system, follow these steps:
•Make electrical connections to the TRAX2.
•Evaluate the TRAX2 using the TRAX Studio program, or a binary terminal emulation
program, such as RealTerm or Tera Term, to ensure the TRAX2 is working properly.
•Choose a mounting location.
•Mechanically mount the TRAX2 in the host system.
•Perform a user calibration.
4.1 Electrical Connections
The TRAX2 PCA incorporates a 6 pin Molex connector, part number 51021-0600, which
mates with Molex part 51021-0600 or equivalent. The pin-out for both is given below in
Table 4-1.
Table 4-1: TRAX2 Pin Descriptions
Pin #1
TRAX2 PCA
6 Pin Molex
Connector
USB Demo
Cable Wire
Color
Pigtailed Cable
1
Ground
Black
Black
2
TTL UART Tx
Yellow
Green
3
TTL UART Rx
Orange
White
4
RS-232 Tx
-
Yellow
5
RS-232 Rx
-
Blue
6
+3.7-8V Power
Red
Red
Footnote:
1. Pin #1 is the left most position of the connector as indicated on Figure
3-2
After making the electrical connections, it is a good idea to perform some simple tests to
ensure the TRAX2 is working as expected. See Section 6 for how to operate the TRAX2 with
TRAX Studio or Section 7 for how to operate the TRAX2 using PNI’s binary protocol.

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4.2 Installation Location
The TRAX2’s wide dynamic range and sophisticated algorithms allow it to operate in many
environments. For optimal performance however, you should mount the TRAX2 with the
following considerations in mind:
4.2.1 Operate within the TRAX2’s dynamic range
The TRAX2 can be user calibrated to correct for static magnetic fields created by the host
system. However, each axis of the TRAX2 has a calibrated dynamic range of ±125 µT. If
the total field exceeds this value for any axis, the TRAX2 may not perform to
specification. When mounting the TRAX2, consider the effect of any sources of magnetic
fields in the host environment that, when added to Earth’s field, may take the TRAX2 out
of its dynamic range. For example, large masses of ferrous metals such as transformers
and vehicle chassis, large electric currents, permanent magnets such as electric motors,
and so on.
4.2.2 Locate away from changing magnetic fields
While the TRAX2 can compensate for transient changes in the local magnetic field, it is
good design practice to keep the TRAX2 away from sources of local magnetic distortion
that knowingly will change with time, such as electrical equipment that will be turned on
and off, or ferrous bodies that will move.
4.2.3 Mount in a physically stable location
Choose a location that is isolated from persistent vibration or other dynamic motion. The
TRAX2 can provide accurate headings while experiencing intermittent dynamic motion,
such as vibration or quick heading changes. But if this is persistent the TRAX2 will have
difficulty holding an accurate heading over extended periods of time.
4.3 Mechanical Mounting
The TRAX2 is factory calibrated with respect to its mounting holes. It must be aligned within
the host system with respect to these mounting holes. Ensure any stand-offs or screws used to
mount the TRAX2 are non-magnetic. Refer to Section 3.2 for dimensions, hole locations, and
the reference frame orientation.

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4.3.1 Pitch and Roll Convention
The TRAX2 utilizes Euler angles as the primary method for providing orientation data,
although quaternions outputs also are available. The Euler angles are the common
method used for aircraft orientation, where the outputs are heading, pitch and roll. When
using Euler angles in aviation, roll is defined as the angle rotated around an axis through
the center of the fuselage, while pitch is rotation around an axis through the center of the
wings. These rotations are dependent on each other since the axes of rotation move with
the plane.
As shown in Figure 4-1, for the TRAX2 a positive pitch is when the front edge of the
board is rotated upward and a positive roll is when the right edge of the board is rotated
downward. The order of rotation is given as heading, pitch, and then roll.
Figure 4-1: Positive & Negative Roll and Pitch Definition
4.3.2 Coordinate System
The TRAX2 utilizes North East Down (NED) coordinate system (frame) to define X, Y
and Z axes as shown in Figure 4-1.
4.3.3 Mounting Orientation
The TRAX2 can be mounted in 16 different orientations, as shown in Figure 4-2. All
reference points are based on the silk-screened arrow on the top side of the TRAX2 PCA
board. The orientation should be programmed in the TRAX2 using the Configuration Tab
in TRAX Studio or using the kSetConfig command and the kMountingRef setting in the
PNI Protocol, as described in Section 7.4.2. The default orientation is “STD 0°”.

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Figure 4-2: TRAX2 Enclosed Mounting Orientations

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5 User Calibration
The magnetic sensor in the TRAX2 is calibrated at PNI’s factory in a magnetically controlled
environment. However, sources of magnetic distortion positioned near the TRAX2 in the user’s
system will distort Earth’s magnetic field and should be compensated for in the host system with
a user calibration. Examples of such sources include ferrous metals and alloys (ex. iron, nickel,
steel, etc.), batteries, audio speakers, current-carrying wires, and electric motors. Compensation
is accomplished by mounting the TRAX2 in the host system and performing a user calibration. It
is expected the sources of magnetic distortion remain fixed relative to the TRAX2‘s position
within the host system. By performing a calibration, the TRAX2 identifies the local sources of
magnetic distortion and negates their effects from the overall reading to provide an accurate
heading.
Key Points:
•Magnetic calibration:
oRequires incorporating the TRAX2 into the user’s host system such that the
magnetic components of the user’s system can be compensated for.
oAllows for 4 different methods of calibration. Full-Range Calibration provides the
highest heading accuracy but requires ≥30°of pitch. 2D and Limited-Tilt
Calibration allow for good calibration when the range of allowable motion is
limited. Hard-Iron-Only Calibration updates the hard-iron compensation
coefficients with a relatively easy procedure.
•If the TRAX2 will experience different states during operation, such as operating with a
nearby shutter sometimes closed and sometimes open, or operating over a broad
temperature range, then different sets of calibration coefficients can be saved for the
various states. Up to 8 magnetic calibration coefficient sets can be saved.
As with the magnetic sensor, the accelerometer in the TRAX2 is calibrated at PNI’s factory.
In the unlikely event the accelerometer drifts the user can perform a user accelerometer
calibration or return the unit to PNI for recalibration. Please refer to the Accelerometer Field
Calibration Application Note for further information.
5.1 Magnetic Calibration
Two fundamental types of magnetic distortion exist: hard-iron and soft-iron. These are
discussed in the following paragraphs, plus a discussion on how temperature also affects
magnetic fields and other considerations. For more information on magnetic distortion and
calibration, see PNI’s white paper “Local Magnetic Distortion Effects on 3-Axis

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Compassing” at PNI’s website (https://www.pnicorp.com/download/magnetic-distortion-
explanation-testing/).
Hard-Iron Effects
Hard-iron distortions are caused by permanent magnets and magnetized objects in
close proximity to the sensors. These distortions add or subtract a fixed component to
each axis of the magnetic field reading. Hard-iron distortions usually are unchanging
and in a constant location relative to the sensors, for all heading orientations.
Soft-Iron Effects
Magnetically “soft” materials effectively bend the magnetic field near them. These
materials have a high magnetic permeability, meaning they easily serve as a path for
magnetic field lines. Unlike hard-iron effects, soft-iron effects do not increase or
decrease the total field in the area. However, the effect of the soft-iron distortion
changes as the host system’s orientation changes. Because of this, it is more difficult
to compensate for soft-iron materials.
Temperature Effects
While the hard-iron and soft-iron distortion of a system may remain quite stable over
time, normally the distortion signature will change over temperature. As a general
rule, the hard-iron component will change 1% per 10°C temperature change. Exactly
how this affects heading depends on several factors, most notably the hard-iron
component of the system and the inclination, or dip angle.
Consider the example of a host system with a 100 µT hard-iron component. This is a
fairly large hard-iron component, but not completely uncommon. A 10°C temperature
change will alter the magnetic field by ~1 µT in the direction of the hard-iron
component. The San Francisco area has an inclination of ~60°, which results in up to
a couple of degrees of heading change over 10°C.
Consequently, no matter how stable a compass is over temperature, it is wise to
recalibrate over temperature since the magnetic signature of the host system will
change over temperature. The TRAX2 helps accommodate this issue by allowing the
user to save up to 8 sets of magnetic calibration coefficient sets, so different
calibration coefficients can be generated and loaded at different temperatures.
Other Considerations
Unlike a digital magnetic compass, such as PNI’s TCM module, the TRAX2 has an
AHRS mode that incorporates a gyroscope and as such it can compensate for
transient changes in the local magnetic field. However, the TRAX2 will work best if
it is kept away from dynamic magnetic fields. For example, if there is an electric

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motor in the host system that will be turning on and off during TRAX2 operation,
then mount the TRAX2 far away from the motor such that the motor’s state does not
affect the heading when TRAX2 is in Compass Mode. Alternatively, TRAX2 can
store up to 8 different sets of magnetic calibration coefficients, so in the case of the
motor, generate and use one set of magnetic calibration coefficients for when the
motor is off and another set for when it is on.
The main objective of a magnetic user calibration is to compensate for hard-iron and soft-
iron distortions to the magnetic field caused by components within the user’s host system. To
that end, the TRAX2 needs to be mounted within the host system and the entire host system
needs to be moved as a single unit during a user calibration. The TRAX2 allows the user to
perform a calibration only in a 2D plane or with limited pitch but provides the greatest
accuracy if the user can rotate through 360° of heading and at least ±30°of pitch. Normal
compass calibration requests tilt in both pitch and roll. For TRAX2, roll is not required.
TRAX2 enhances calibration flexibility and improves heading accuracy.
The following subsections provide instructions for performing a magnetic calibration of a
TRAX2 system. Several calibration mode options exist, as summarized in Table 5-1. To meet
the accuracy specification, the number of samples should be the “Minimum Recommended”
value, or greater. Calibration may be performed using TRAX Studio or using the PNI binary
protocol, and up to 8 sets of magnetic calibration coefficients may be saved. The
recommended calibration patterns described in the following sub-sections provide a good
distribution of sample points. Also, PNI recommends the location of the TRAX2 remain
fixed to the system while the orientation of the system is changed during calibration.
Table 5-1: Magnetic Calibration Mode Summary
Calibration
Mode
Static Accuracy in
Compass Mode
Pitch
Range
during Cal
Minimum
Recommended
# of Samples
Allowable
Range of #
of
Samples1
Full-Range
0.3° rms
>±30°
12
10 –32
2D Calibration
<2°
<±5°
12
10 –32
Limited-Tilt
<2° over 2x tilt range
±5° to ±30°
12
10 –32
Hard-Iron-Only
Restores prior
accuracy
>±30°
6
4 - 32
Footnote:
1. Maximum number of sample point is 32 in TPTCM. When TRAX studio is used to
evaluate, the studio has limited sample point up to 18.

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Before proceeding with a calibration, ensure the TRAX2 is properly installed in the host
system. The device should be installed as discussed in Section 4, and the software should be
properly configured with respect to the mounting orientation, Endianness, north reference,
etc.
Section 6.5 outlines how to perform a calibration using TRAX2 Studio, while Section 7.6.2
provides a step-by-step example of how to perform a calibration using the PNI protocol.
5.1.1 Full-Range Calibration
A Full-Range Calibration is appropriate when the system with the TRAX2 installed can
be pitched ±30° or more. This method compensates for hard and soft-iron effects in three
dimensions and allows for the highest accuracy readings. The recommended 12 point
calibration pattern is a series of 2 circles of evenly spaced points, as illustrated in Figure
5-1 as the realistic view and listed in Table 5-2. The pitch used in the two circles of the
calibration should at least match the maximum and minimum pitch the device is expected
to encounter in use.
Table 5-2: 12 Point Full-Range Calibration Pattern
Sample #4
Heading1
Pitch2
Roll3
First Circle
1
0°
≥+30°
0°
2
60°
≥+30°
0°
3
120°
≥+30°
0°
4
180°
≥+30°
0°
5
240°
≥+30°
0°
6
300°
≥+30°
0°
Second Circle
7
0°
≤ -30°
0°
8
60°
≤ -30°
0°
9
120°
≤ -30°
0°
10
180°
≤ -30°
0°
11
240°
≤ -30°
0°
12
300°
≤ -30°
0°
Footnote:
1. Heading listings are not absolute heading directions, but rather relative heading
referenced to the first sample.
2. Pitch 30° or more is recommended; acceptable range is between ±10° to ±60°.
3. Roll is not required.

PNI Sensor DOC#1032877
TRAX2 User Manual Aug 2021 Page 16
4. The sequence order of sample points is not required. The 12 points can be sampled
in any order. Samples can be taken in one circle in the following order: 1, 7, 2, 8, 3, 9,
4, 10, 5, 11, 6, 12.
Figure 5-1: 12 Point Full-Range Calibration (Realistic View)
Notes
•The location of the device changing in realist view, this is for illustration purpose. If
possible, it is best to rotate around the center of the device as a pivot point.
•It is not necessary for the unit to be pointing North to start; however, it may provide
better results, especially in high latitudes.