OXTS xOEM500 Quick setup guide

Hardware
Integration
Manual
xOEM500 and xOEM550
Inertial and GNSS
measurement system

Oxford Technical Solutions Ltd www.oxts.com Page 1 of 22
Legal notices
Information furnished is believed to be accurate and reliable. However, Oxford Technical Solutions
Limited assumes no responsibility for the consequences of use of such information nor for any
infringement of patents or other rights of third parties which may result from its use. No licence is
granted by implication or otherwise under any patent or patent rights of Oxford Technical Solutions
Limited. Specifications mentioned in this publication are subject to change without notice and do not
represent a commitment on the part of Oxford Technical Solutions Limited. This publication
supersedes and replaces all information previously supplied. Oxford Technical Solutions Limited
products are not authorised for use as critical components in life support devices or systems without
express written approval of Oxford Technical Solutions Limited.
All brand names are trademarks of their respective holders.
The software is provided by the contributors “as is” and any express or implied warranties, including,
but not limited to, the implied warranties of merchantability and fitness for a particular purpose are
disclaimed. In no event shall the contributors be liable for any direct, indirect, incidental, special,
exemplary, or consequential damages (including, but not limited to, procurement of substitute goods
or services; loss of use, data, or profits; or business interruption) however caused and on any theory
of liability, whether in contract, strict liability, or tort (including negligence or otherwise) arising in any
way out of the use of this software, even if advised of the possibility of such damage.
Copyright notice
© Copyright 2021, Oxford Technical Solutions.
Unauthorised use, copying or distribution is not permitted. All brand names are trademarks of their
respective holders.
The software also includes software in binary form from:
Xiph.Org Foundation at xiph.org. Copyright © 2002, Xiph.org Foundation
TI at software-dl.ti.com.
Copyright © 2002–2015, Texas Instruments Incorporated All rights reserved.
None of the names of the Xiph.org Foundation or Texas Instruments Incorporated, nor the names of
their contributors may be used to endorse or promote this product or products using this software
without specific prior written permission.
Any redistribution of the software must reproduce the above copyright notice, this list of conditions
and the following disclaimer in the documentation and/or other materials provided with the distribution.
Revision
Document Revision: 210326 (See Revision History for detailed information).

Oxford Technical Solutions Ltd www.oxts.com Page 2 of 22
Contact details
Oxford Technical Solutions Limited
Park Farm Business Centre
Middleton Stoney
Oxfordshire
OX25 4AL
United Kingdom
Tel: [phone]
Fax: [phone]
Web: https://www.oxts.com
Email: [email protected]
Warranty
Oxford Technical Solutions Limited warrants its products to be free of defects in materials and
workmanship, subject to the conditions set forth below, for a period of one year from the Date of Sale.
“Date of Sale” shall mean the date of the Oxford Technical Solutions Limited invoice issued on
delivery of the product. The responsibility of Oxford Technical Solutions Limited in respect of this
warranty is limited solely to product replacement or product repair at an authorised location only.
Determination of replacement or repair will be made by Oxford Technical Solutions Limited personnel
or by personnel expressly authorised by Oxford Technical Solutions Limited for this purpose.
In no event will Oxford Technical Solutions Limited be liable for any indirect, incidental, special, or
consequential damages whether through tort, contract or otherwise. This warranty is expressly in lieu
of all other warranties, expressed or implied, including without limitation the implied warranties of
merchantability or fitness for a particular purpose. The foregoing states the entire liability of Oxford
Technical Solutions Limited with respect to the products herein.
Any use or misuse of the product in a manner not intended may impair the protection provided.
Improper installation or usage of the device can lead to malfunction, loss of data, equipment damage,
and physical injury. The user is responsible for conducting a proper risk assessment when integrating
the product. Please contact OxTS if you believe any service or repair is required on your product.
Environmental protection
Waste electrical products should not be disposed of with household waste. Please recycle where
facilities exist. Check with your Local Authority or OxTS representative for recycling advice.

Oxford Technical Solutions Ltd www.oxts.com Page 3 of 22
Contents
Legal notices .......................................................................................................................................1
Copyright notice...................................................................................................................................1
Revision...............................................................................................................................................1
Contact details.....................................................................................................................................2
Warranty..............................................................................................................................................2
Environmental protection.....................................................................................................................2
Introduction .............................................................................................................................................5
Related documents.................................................................................................................................5
Precautions .............................................................................................................................................6
Compliance testing..............................................................................................................................6
Hardware description..............................................................................................................................6
Overview..............................................................................................................................................6
Architecture .........................................................................................................................................7
Model variations ..................................................................................................................................7
Board dimensions................................................................................................................................8
Board layout ........................................................................................................................................9
LED definitions ..................................................................................................................................11
Connections.......................................................................................................................................12
Co-ordinate frame and origin point....................................................................................................12
Design-in...............................................................................................................................................13
Main connector..................................................................................................................................13
Connector pin out..............................................................................................................................13
Connector specifications ...................................................................................................................15
Power.............................................................................................................................................15
PPS................................................................................................................................................15
Serial..............................................................................................................................................15
Digital IO ........................................................................................................................................15
Antennas........................................................................................................................................15
Mounting........................................................................................................................................16
Heat dissipation.................................................................................................................................19
Power consumption...........................................................................................................................19
Internal storage..................................................................................................................................19
Specifications........................................................................................................................................20
Optional features...............................................................................................................................21
Revision history.....................................................................................................................................22

Oxford Technical Solutions Ltd www.oxts.com Page 4 of 22
List of figures
Figure 1: xOEM block diagram ...............................................................................................................7
Figure 2: xOEM500 dimensions..............................................................................................................8
Figure 3: xOEM550 dimensions..............................................................................................................8
Figure 4: Layout of the xOEM500 board set...........................................................................................9
Figure 5: Layout of the xOEM550 board set...........................................................................................9
Figure 6: Layout of the adaptor board...................................................................................................10
Figure 7: xOEM co-ordinate frame and measurement origin................................................................12
Figure 8: Connector pin layout..............................................................................................................13
Figure 9: xOEM500 clearances and mounting points...........................................................................17
Figure 10: xOEM550 clearances and mounting points.........................................................................18
List of tables
Table 1: Supplementary documents.......................................................................................................5
Table 2: xOEM board descriptions........................................................................................................10
Table 3: GNSS LED states ...................................................................................................................11
Table 4: Status LED states...................................................................................................................11
Table 5: Power LED states ...................................................................................................................11
Table 6: Direction of axes for zero heading, pitch and roll outputs.......................................................12
Table 7: Main connector pin allocations................................................................................................14
Table 8: xOEM specifications ...............................................................................................................20
Table 9: Optional features available for purchase................................................................................21
Table 10: Revision history.....................................................................................................................22

Oxford Technical Solutions Ltd www.oxts.com Page 5 of 22
Introduction
Thank you for choosing an xOEM series inertial navigation system. This OEM board set version of the
xNAV series combines embedded dual GNSS receivers and tactical-grade IMU in one easy to
integrate package. The compact form factor does not sacrifice accuracy, it provides system
integrators with a high performance GNSS-aided inertial navigation system perfect for any application
where continuous position and orientation is required.
The xOEM series retains all the features and performance of the xNAV series, including dual GNSS
receivers, real-time 100/200/250 Hz outputs, DGPS corrections, tight-coupling and advanced gx/ix
processing technology, but without an enclosure. This cuts the weight by more than half and makes
the xOEM ideal for integrating into space limited or weight restricted systems. Standard NMEA
messages and a 1PPS signal are available to synchronise with other sensors and decoders are freely
available for the full NCOM outputs.
This manual covers the technical information required to successfully integrate the xOEM into your
system. For information on configuring and operating the xOEM, please see the full xNAV User
Manual. The following chapter lists additional available documentation that may be of use when using
the xOEM. It is beyond the scope of this manual to provide details on service or repair. Contact OxTS
support or your local representative for any customer service-related inquiries.
Related documents
There are separate manuals available for further information on some of the software and
communication types mentioned in this manual. Table 1 lists related manuals and where to find them.
Table1: Supplementarydocuments
Manual
Description
xNAV user manual
User manual covering the full operation of thexNAV systems. The xOEMseries
behaves identically to the xNAV series.
https://oxts.box.com/s/t2hcbi3wrwj2dcaynhr8mhkifubb2tnd
NAVgraph manual
User manual for the graphing and display software NAVgraph.
https://oxts.box.com/s/lonucpgrqhecn4qql50lqksa5grapw57
NCOM description
manual
Describes the NCOM format, OxTS’s binary output format with all the
navigation and most status information in.
https://oxts.box.com/s/jovnqyj3lkcht2b2159jefzbt950j1n1
NCOM C code
drivers
A collection of C functions that can be used to decode the binary protocols from
the xOEM.
https://github.com/OxfordTechnicalSolutions/NCOMdecoder
XCOM description
manual
Describes the XCOM format, a container format that can create many logical
output streams from a single physical stream.
Contact OxTS for this document
NMEA 0183
description
NMEA description manual for the NMEA outputs.
https://oxts.box.com/s/v3dhlshoi6q6mpxwr48pd151an75bfvl
NAVsolve manual
User manual for the post-processing software NAVsolve.
https://oxts.box.com/s/wr1yk7gfuf58upankxowvrymgfdfgd7q
xOEM500 DevKit
technical note
The description, source code and the schematic diagrams for the xOEM500.
Customers are required to sign an NDA to gain access to this document.

Oxford Technical Solutions Ltd www.oxts.com Page 6 of 22
Precautions
The xOEM contains delicate, exposed electronic circuits and components that can be damaged by
electrostatic discharge (ESD). When handling, care must be taken so that the device is not damaged.
Damage due to inappropriate handling is not covered by the warranty.
Prior to installation it is recommended to carefully read this manual and ensure the following
precautions are taken:
▪Do not open the protective packaging until you have read the following and are at an approved
anti-static workstation.
▪It is best to wear an ESD wrist strap when handling electronic components. If you do not have
an ESD wrist strap, keep your hands dry and first touch a metal object to eliminate static
electricity.
▪When handling the system, avoid touching any metal leads or connectors.
▪If working on a prototyping board, use a soldering iron or station that is marked as ESD-safe.
▪Always discharge yourself by touching a grounded bare metal surface or approved anti-static
mat before picking up an ESD-sensitive electronic component.
▪Use an approved anti-static mat to cover your work surface.
Compliance testing
OxTS has not carried out any regulatory compliance testing for this product as it is solely intended for
system integration and development purposes. This product should not be used in an end user
application without undergoing regulatory compliance testing as part of another complete product.
The xNAV systems; the enclosed versions of the xOEM systems, have passed regulatory compliance
testing so there is no reason to believe that the xOEM would affect the outcome of testing when
properly integrated into an end product.
Any use or misuse of the xOEM in a manner not intended may impair the protection provided. OxTS
is not liable for any damages caused by the misuse of the equipment
Hardware description
Overview
The xOEM is a miniature GNSS-aided inertial navigation system. It combines dual GNSS receivers
with a tactical-grade IMU to provide a compact navigation solution. Built as a board-set configuration,
the system also includes 32 GB data storage and an on-board processor running the real-time
strapdown navigator and Kalman Filter.
The dual receiver integration allows greater heading accuracy with wider antenna baselines and
ensures stable heading performance even when stationary and during low dynamics. The custom
built 6-axis IMU consists of high-grade MEMS gyros and accelerometers. The sensor fusion between
the GNSS receivers and inertial sensors is done seamlessly in real-time for a continuous 100 Hz
navigation output. Data is automatically logged to the 32 GB eMMC for added data protection and
redundancy.

Oxford Technical Solutions Ltd www.oxts.com Page 7 of 22
Architecture
The xOEM system is made up of two main building blocks, the xOEMcore and the ADK platform. The
ADK consists of the GNSS receivers, System on Module (SoM), interfaces, logging and
communication. The xOEMcore contains the IMU block and main navigation processor. The two
blocks are connected by a high-speed serial cable but are not physically mounted together. Although
they can be mounted independently, most drawings in this manual display the two parts in-line
horizontally. Figure 1 shows the xOEM block diagram.
Figure1: xOEM blockdiagram
The xOEMcore houses the 6-axis IMU and the main processor that calculates the navigation solution.
The ADK platform feeds aiding data, configuration files and commands to the xOEMcore; it takes raw
data (RD) and navigation data from the xOEMcore, writes RD files and sends the navigation data out
over serial and Ethernet interfaces.
Model variations
There are two models available in the xOEM series: the xOEM500 and xOEM550. Both systems use
the xOEMcore with the same inertial sensors. The only difference is the GNSS receivers.
▪xOEM500: Single frequency (L1), GPS and GLONASS.
▪xOEM550: Dual frequency (L1/L2), GPS, GLONASS and BEIDOU.
Note: Triple constellation (GPS+GLONASS+BEIDOU) is not recommended due to processing
constraints. GPS+GLONASS or GPS+BEIDOU options are available.

Oxford Technical Solutions Ltd www.oxts.com Page 8 of 22
Board dimensions
The outer dimensions of the xOEM500 and xOEM550 are shown in Figure 2 and Figure 3
respectively.
Figure2:xOEM500dimensions
Figure3: xOEM550dimensions

Oxford Technical Solutions Ltd www.oxts.com Page 9 of 22
Board layout
The board layouts with main components labelled for the xOEM500 and xOEM550 are shown in
Figure 4 and Figure 5. The included adaptor board a connector breakout for the pin header, shown in
Figure 6. Table 2 lists details for the corresponding labels.
Figure4: Layout ofthexOEM500boardset
Figure5: Layout ofthexOEM550boardset

Oxford Technical Solutions Ltd www.oxts.com Page 10 of 22
Figure6: Layout oftheadaptorboard
Table2: xOEMboarddescriptions
Label
no.
xOEM500
xOEM550
Adaptor board
1
xOEMcore
xOEMcore
Ethernet port
2
Primary and secondary
GNSS receivers
Secondary GNSS receiver
(primary receiver hidden
underneath)
DC socket
3
Primary antennaconnector
Primary antenna connector
(5 V)
9-pin female serialport
4
Secondary antenna
connector
(Not in view) Primary
antennaconnector (3.3 V)
Connector pinheader
5
GNSS LED
Secondary antenna
connector (3.3 V)
6
Status LED
Secondary antenna
connector (5 V)
7
Power LED
GNSS LED
8
Main connector female
header
Status LED
9
-
Power LED
10
-
Main connector pin header

Oxford Technical Solutions Ltd www.oxts.com Page 11 of 22
LED definitions
Three LEDs on the xOEM board set show the system’s state when power is applied. Table 3, Table 4,
and Table 5 give details on the meanings of the states of each LED.
Table3: GNSSLEDstates
Colour
Description
Off
GNSS receiver fault (valid only after start-up).
Red flash
GNSS receiver is active but has been unable to determine heading.
Red
The GNSS has a differential heading lock.
Orange
The GNSS receiver has a floating (poor) calibrated heading lock.
Green
The GNSS receiver has an integer (good) calibrated heading lock.
Table4: StatusLEDstates
Colour
Description
Off
The operating system has not yet booted and the program is not yet running.
This occursat start-up.
Red-greenflash
The xOEM is asleep. Contact OxTS support for further information.
Red flash
The operating system has booted and the program is running. The GNSS
receiver has notyet output a valid time, position, or velocity.
Red
The GNSS receiver has locked-on to satellites and has adjusted its clock to
valid time (the1PPS output will now be valid). The strapdown navigator is ready
to initialise. If the vehicle is travelling faster than the value set for “Initialisation
speed” during configuration then the strapdown navigator will initialise and the
system will become active. If static initialisation has been enabled the system
will initialise once the GNSS receiver has determined heading, even if the
vehicle is stationary or moving slowly.
Orange
The strapdown navigator has initialised and data is being output, but the
system is notreal-time yet. It takes 10 s for the system to become real-time
after start up.
Green
The strapdown navigator is running and the system is real-time.
Table5: PowerLEDstates
Colour
Description
Off
There is no power to the system or the system power supply has failed.
Green
Power is applied to the system.
Orange
The system is powered and traffic is present on Ethernet.

Oxford Technical Solutions Ltd www.oxts.com Page 12 of 22
Connections
The main connector for both xOEM models is a Samtec CLP-111-02-L-D. This is a 22 pin header with
1.27 mm spacing.
The antenna connectors on the xOEM500 are MMCX. On the xOEM550 the antenna connectors are
Hirose H.FL.
Co-ordinate frame and origin point
The xOEM uses a co-ordinate frame that is popular with most navigation systems. Figure 4 shows
how the axes relate to the xOEM board. All measurements to and from the xOEM should be made
from the measurement origin point shown in Figure 7. The origin point is the same for all xOEM
models.
Figure7: xOEMco-ordinate frameandmeasurementorigin
Table 6 lists the directions that the axes should point for zero heading, pitch and roll outputs when the
default mounting orientation is used.
Table6: Directionofaxesforzeroheading,pitch and rolloutputs
Axis
Direction
Host axis
x
North
Forward
y
East
Right
z
Down
Down
The xOEM can be mounted in any orientation, it is not necessary for its axes to match those in Table
6. If a different mounting orientation is used then it must be specified in the configuration file. This can
be accomplished with the NAVconfig software.

Oxford Technical Solutions Ltd www.oxts.com Page 13 of 22
Design-in
Main connector
OxTS recommends that you mount directly to the xOEM with a connecting board using Samtec
FTSH-111-02-L-D. 5 mm space should be left between the mounting points for the xOEM and the
mounting points for the mating board to allow room for the two connectors. Alternative mating
connectors are available from Samtec or from alternative suppliers. All xOEM boardsets come with an
adapter board. This PCB will mount directly to the interconnect and houses the Ethernet RJ45 socket,
the EMI filters, a DC power socket and a 9 way d-type with a configurable pinout.
Connector pin out
Figure 8 shows the pin layout for the main connector on the xOEM. Table 7 lists the pin numbers and
their corresponding functions.
Figure8: Connectorpin layout

Oxford Technical Solutions Ltd www.oxts.com Page 14 of 22
Table7: Mainconnectorpinallocations
Pin
Function
Description
1
+ Supply
Power supply +
2
- Supply
Power supply -
3
+ Supply
Power supply +
4
- Supply
Power supply -
5
PPS_SYNC_A_Ext
PPS = output PPS (GNSS)
SYNC = output sync (xOEMcore)
Ext = input PPS (external GNSS)
6
Signal GND
Signal ground
7
S3Tx
Serial 3 Tx (configurable)
8
Signal GND
Signal ground
9
S3Rx
Serial 3 Rx (configurable)
10
Earth
Chassis earth signal
11
Trig2_Ext
Trigger 2 input/output (configurable)
12
UART1_TX_TX+
Serial 1 Tx or Serial 1 Tx+ in RS422 mode
13
Trig1_Ext
Trigger 1 input/output (configurable)
14
UART1_RX_RX+
Serial 1 Rx or Serial 1 Rx+ in RS422 mode
15
UART2_RX_RX-
Serial 2 Rx or Serial 1 Rx- in RS422 mode
16
WS1_Ext
TTL input from odometer
17
UART2_TX_TX-
Serial 2 Tx or Serial 1 Tx- in RS422 mode
18
WS2_DIFF_PPS_Ext
WS2 = TTL input for quadrature odometer
DIFF_PPS = negative pin for differential PPS signal
19
ETX+
Ethernet transmit +
20
ERX-
Ethernet receive -
21
ETX-
Ethernet transmit -
22
ERX+
Ethernet receive +

Oxford Technical Solutions Ltd www.oxts.com Page 15 of 22
Connector specifications
Power
The power supply input for the xOEM is 10–31 V DC.
PPS
The 1PPS output signal is output from the primary GNSS receiver when a valid solution is found. The
output is a low-voltage TTL 3.3 V output where 0.8 V or less is low and 2.0 V or more is high.
1PPS input from an external source is 3.3 V low-voltage TTL, but tolerant of up to 5 V.
Serial
All 3 Serial connections adhere to standard voltages for RSR232 (±5 V).
Digital IO
All Digital IO connections are LVCMOS.
When configured as an input, the triggers see less than 0.8 V as low and more than 2.4 V as high.
The input range should be kept between 0 V and 5 V. The inputs have pull-up resistors so they can
be used with a switch or as a CMOS input. The resistors are 10 kΩ and pull-up to 3.3 V.
When configured as an output, the triggers have 0.8 V or less as low and 2.4 V or more as high. The
“slow trigger” pulse width is 1 ms. Slow triggers are used when the output rate is lower than the
periodic output of the INS e.g. less than 100 Hz on a system configured to run the navigation engine
at 100 Hz.
Output triggers can be also be output using a feature known as “fast triggers”. Fast triggers are used
when the output rate is higher than the periodic output rate of the INS, e.g pulse per metre rate is
higher than 100 Hz on a system configured to run the navigation engine at 100 Hz. The timing
accuracy of fast triggers is not as precise as slow triggers.
The odometer input requires less than 0.8 V for a low pulse and more than 2.4 V for a high pulse.
Limited protection is provided on this input, however the input voltage should not exceed 12 V.
Antennas
The xOEM500 GNSS modules receive L1 GPS signals at a nominal frequency of 1575.42 MHz, and
can receive L1 GLONASS signals at 1602.0 MHz. Antennas used with the xOEM500 must be capable
of tracking this signal for correct operation.
The xOEM550 GNSS modules receive L1 and L2 GPS signals at a nominal frequency 1575.42 MHz
and 1227.60 MHz respectively, and can receive L1 and L2 GLONASS signals spanning either side
from 1602.0 MHz and 1246.0 Hz respectively. Antennas used with the xOEM550 must be capable of
tracking these signals for correct operation.
The total preamplifier gain (minus cable and interconnect losses) must not exceed 50 dB. The total
antenna noise figure should be below 3 dB.
When using the xOEM in a dual antenna configuration, it is recommended to use the same type of
antenna with the same cable lengths for both the primary and secondary receivers.

Oxford Technical Solutions Ltd www.oxts.com Page 16 of 22
The xOEM550 has two connectors for each receiver, one providing a 3.3 V supply and the other a 5 V
supply to the antenna. Ensure to use the correct connection for your antenna, and only connect to a
single connector on each receiver.
Mounting
Figure 9 and Figure 10 show the mounting points and required clearances for the xOEM500 and
xOEM550 respectively. It is important when mounting the xOEM board sets not to stress the IMU
mechanically in any way as this can change the alignment of the sensors and degrade the calibration.
The mounting holes on the xOEM frame are suitable for M2.5 threaded screws. A torque setting of
0.4 Nm should be used. For general use in permanent installations, Loctite 270 threadlocker is
recommended. Depending on the installation environment, different threadlock may be needed. It is
recommended that you mount all xOEM products so that the screws go into the mounting points from
the top. This makes designing mounting points easier as all the mounting points are in the same
plane. The height of the mounting points should all be within +/- 0.2 mm of each other so as to not
stress the IMU. If mounting differently please refer to the mechanical models, which can be obtained
by contacting OxTS directly, to determine the height required for the mounting points.
There is no reason that the two frames must be mounted joined in the same way. If you wish to mount
them differently please refer to the figures below or the mechanical models for the mounting
measurements. In this case all measurements and angles are in respect to the xOEMcore part of the
arrangement.

Oxford Technical Solutions Ltd www.oxts.com Page 17 of 22
Figure9: xOEM500clearancesandmountingpoints

Oxford Technical Solutions Ltd www.oxts.com Page 18 of 22
Figure10: xOEM550 clearancesandmountingpoints

Oxford Technical Solutions Ltd www.oxts.com Page 19 of 22
Heat dissipation
The upper operating temperature of the xOEM board set is 70°C, therefore it should be mounted in a
location where this temperature will not be exceeded. The xOEMcore is designed so that the excess
heat is dissipated into its frame. The most effective way to keep the xOEMcore cool is to mount the
frame to something thermally conductive and cool. General xOEM cooling can be aided by mounting
in an area where air can circulate. It is also recommended that the metal canned DCDC converter on
the bottom of the xOEM board set is thermally connected to something for cooling if possible. The
SOM should also have heat sinking applied as well as being held in place. OxTS recommend using a
GapPad to a metal surface below it to achieve this fixing and ideal heat dissipation.
Power consumption
As with other electronic devices the power consumption of the xOEM is affected by the environmental
conditions it is operating in and by its power source. Tests carried out by OxTS have shown that the
best power consumption is achieved with a 12 V power input and at room temperature (20–25°C). It is
also recommended to not use excessively long antenna or power cables to reduce power loss in
cabling.
Internal storage
The xOEM uses a 32 GB eMMC for storage of hardware information, configuration files, and
navigation data. Files can be sent to or retrieved from the card via FTP or with the software utilities
provided (NAVconfig for configuration files and NAVsolve for data files).