Oxford Technical Solutions xNAV User manual

xF
Confidently. Accurately.
xNAV
GNSS-aided inertial
measurement
system
User Manual
Covers all xNAV models

2
Oxford Technical Solutions
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 license 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 2016, Oxford Technical Solutions.
Revision
Document Revision: 160412 (See Revision History for detailed information).
Contact Details
Oxford Technical Solutions Limited
77 Heyford Park
Upper Heyford
Oxfordshire
OX25 5HD
United Kingdom
Tel: [phone]
Fax: [phone]
Web: http://www.oxts.com
Email: [email protected]

4
Oxford Technical Solutions
Table of contents
Scope of delivery 6
Introduction 7
Related documents 8
Conformance notices 9
Regulator testing standards 9
Basic information 10
Precautions 10
Model variations 10
Front panel layout 10
LED definitions 11
Co-ordinate frame conventions 12
Ethernet configuration 13
Software installation 16
Hardware installation 18
Antenna placement and orientation 18
Configuring the xNAV 20
Selecting the operating language 20
Navigating through NAVconfig 20
Product selection 21
Read configuration 22
Orientation 23
Primary antenna position 24
Secondary antenna position 25
Wheel configuration 27
Options 29
IMU output rate 30
Vehicle starts 30
Vibration 30
GNSS weighting 31

xNAV User Manual
Revision: 160412
5
Heading lock 31
SBAS 32
Initialisation speed 32
Displace output 32
Odometer input 32
Trigger 1 and Trigger 2 (xNAV5**) 34
Serial input (xNAV5**) 35
Serial 1 output 36
Ethernet output (xNAV5**) 39
Output smoothing 40
GNSS control 40
Coordinate system 42
1PPS 43
Output lock 43
Advanced 43
Committing the configuration 44
Saving the configuration and finishing 44
Operating the xNAV 46
Initialisation and warm-up 46
Downloading data 47
Improve the configuration with Get improved settings 47
Specifications 49
Revision history 50
Drawing list 51

6
Oxford Technical Solutions
Scope of delivery
Table 1 lists the standard items delivered with each xNAV. Everything required to
operate the xNAV successfully is included. Please ensure everything is present upon
delivery.
Table 2 lists a number of optional parts that may be used with an xNAV. For more
information on these components please contact your OxTS representative or email
[email protected].
Table 1. Summary components supplied with an xNAV
Qty.
xNAV200
xNAV500
xNAV250
xNAV550
1
xNAV system unit
xNAV system unit
2
AT575-70 GNSS antenna with 5 m cable
G5Ant-1A196MNS1 GNSS antenna with 5 m
cable
1
User cable (14C0091F)
User cable (14C0091F)
1
CD –ROM with software and manuals
CD –ROM with software and manuals
4
90° mounting brackets
90° mounting brackets
1
xNAV user manual
xNAV user manual
Table 2. Compatible xNAV accessories
Part
Description
RT-Strut
Designed to quickly and securely provide a
mounting location inside a road vehicle.
RT-Strut mounting bracket
Quickly attach the xNAV to an RT-Strut.
RT-UPS
An uninterruptible power supply capable of
powering the xNAV for up to 1 minute after power
is lost. Input 9–48 V dc.

xNAV User Manual
Revision: 160412
7
Introduction
Thank you for choosing the xNAV. It is a high-performance GNSS-aided inertial
navigation system designed to meet the tough demands of aerial and ground-based
surveying applications—especially where space and weight are important. As a one-
box solution it is quick and easy to install and configure but does not compromise on
accuracy or reliability.
Utilising dual antennas, DGPS corrections, tight-coupling and advanced gx/ix
processing technology the xNAV delivers up to 2 cm position and 0.1° heading
accuracy (2 m antenna separation) with up to 250 Hz output for all measurements.
4 GB of raw data (max. 2 GB per file), corresponding to over 24 hours’ worth of
IMU+GNSS data can be logged and stored internally and quickly downloaded via
Ethernet. The xNAV5** models can output all measurements in real-time with very
low latency. The xNAV2** models log data automatically which can be post-processed
later with the powerful software included with NAVsuite.
This manual covers the installation, configuration and basic operation of the xNAV.
Separate manuals are provided for the post-processing and graphing software of
NAVsuite. An xNAV quick start guide is available on the OxTS website, but we
suggest reading the entire manual in order to become thoroughly familiar with the
product. 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.

8
Oxford Technical Solutions
Related documents
There are separate manuals available for further information on some of the software
and communication types mentioned in this manual. Table 3 lists related manuals and
where to find them.
Table 3. Supplementary manuals
Manual
Description
NAVdisplay
Manual
User manual for real-time display software NAVdisplay.
www.oxts.com/Downloads/Support/Manuals/NAVdisplayman.pdf
NAVgraph
Manual
User manual for the graphing and display software NAVgraph.
www.oxts.com/Downloads/Support/Manuals/NAVgraphman.pdf
NCOM
Manual
NCOM description manual.
www.oxts.com/Downloads/Support/NCOM Manual and Code Drivers/ncomman.pdf
NCOM C
Code Drivers
A collection of C functions that can be used to decode the binary protocols from the
RT.
www.oxts.com/Downloads/Support/NCOM Manual and Code Drivers/ncomrx.zip
NMEA 0183
Description
NMEA description manual for the NMEA outputs.
www.oxts.com/Downloads/Support/NMEA/nmeaman.pdf
RT Post-
process
Manual
User manual for the post-processing software RT Post-process.
www.oxts.com/Downloads/Support/Manuals/rtppman.pdf
xNAV quick-
start guide
Short guide going over the basics needed to quickly set up and start using an xNAV.
http://www.oxts.com/Downloads/Products/xNAV/xNAV quick start guide.pdf

xNAV User Manual
Revision: 160412
9
Conformance notices
The xNAV complies with the radiated emission limits for 47CFR15.109:2010 class A
of Part 15 subpart B of the FCC rules, and with the emission and immunity limits for
class A of EN 55022. These limits are designed to provide reasonable protection
against harmful interference in business, commercial and industrial uses. This
equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and on, the
user is encouraged to try to correct the interference by one or more of the following
measures:
Re-orient or relocate the receiving antenna
Increase the separation between the equipment and the receiver
The xNAV incorporates a GNSS receiver. Any GNSS receiver will not be able to track
satellites in the presence of strong RF radiations within 70 MHz of the GNSS
frequencies.
The xNAV conforms to the requirements for CE.
Any use or misuse of the xNAV in a manner not intended may impair the protection
provided. OxTS is not liable for any damages caused by the misuse of the equipment.
Regulator testing standards
47CFR15.109:2010 class A (radiated emissions)
EN 300 440-1 v1.6.1, test methods 8.3.4 (radiated emissions)
EN 55022:2010
EN 55024:2010
EN 61326-2-1:2006 according to the requirements of EN 61326-1:2006
EN 61326-1-1:2013 according to the requirements of EN 61326-1:2013
EN 301 489-3 v1.4.1 according to the requirements of EN 301 489-1 v1.9.2
IEC 61010-1:2010 3rd ed. (safety)

10
Oxford Technical Solutions
Basic information
The xNAV has been designed to be simple and easy to operate. The front panel and
LEDs convey some basic information that aid in configuration and troubleshooting.
Once powered, the xNAV requires no further input from the user to start logging data.
This section covers some basic information required to operate an xNAV.
Precautions
The xNAV is designed to dissipate heat into the case. As such it may be hot after
periods of operation. The system should be allowed to cool after operation and caution
should be taken when handling. If the system is used in situations with high operating
temperatures, forced convection may be required.
Model variations
There are a number of models available in the xNAV series. All models use the same
inertial measurement unit (IMU), have dual GNSS receivers as standard, and output
data at up to 100 Hz as standard (or up to 250 Hz with an optional upgrade). The
differences between models are summarised below.
xNAV200: Single frequency (L1) receivers. GPS tracking, optional GLONASS
tracking. Logging only.
xNAV500: Single frequency (L1) receivers. GPS tracking, optional GLONASS
tracking. Real-time outputs and logging.
xNAV250: Dual frequency (L1, L2) receivers. GPS tracking, optional GLONASS
tracking. Logging only.
xNAV550: Dual frequency (L1, L2) receivers. GPS tracking, optional GLONASS
tracking. Real-time outputs and logging.
Front panel layout
Figure 1 shows the layout of the xNAV front panel and Table 4 lists details of the parts
labelled.

xNAV User Manual
Revision: 160412
11
Figure 1. Layout of the xNAV front panel
The main connector (6) is keyed, so the user cable will only engage when correctly orientated. It is self-
latching to avoid accidental removal. Do not pull on the user cable to remove it as damage may occur.
Table 4. xNAV front panel descriptions
Label no.
Description
1
GNSS LED
2
Status LED
3
Pwr LED
4
Primary antenna connector
5
Secondary antenna connector
6
Main connector
LED definitions
Three LEDs set into the front panel of the xNAV show the system’s state when power
is applied. Table 5, Table 6, and Table 7 give details on the meanings of the states of
each LED.
Table 5. GNSS LED states
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.

12
Oxford Technical Solutions
Table 6. Status LED states
Colour
Description
Off
The operating system has not yet booted and the program is not yet running. This occurs at
start-up.
Red-green
flash
The xNAV is asleep. Contact OxTS support for further information.
Red flash
The operating system has booted and the program is running. The GNSS receiver has not
yet output a valid time, position, or velocity.
Red
The GNSS receiver has locked-on to satellites and has adjusted its clock to valid time (the
1PPS 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 not real-
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.
Table 7. Power (PWR) LED states
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.
Co-ordinate frame conventions
The xNAV uses a co-ordinate frame that is popular with most navigation systems.
Figure 2 shows how the axes relate to the xNAV box. All measurements to and from
the xNAV should be made from the measurement origin point shown in Figure 2. The
origin point is the same for all xNAV models.

xNAV User Manual
Revision: 160412
13
Figure 2. xNAV co-ordinate frame and measurement origin
Table 8 lists the directions that the axes should point for zero heading, pitch and roll
outputs when the default mounting orientation is used.
Table 8. Direction of axes for zero heading, pitch and roll outputs
Axis
Direction
Vehicle axis
x
North
Forward
y
East
Right
z
Down
Down
If the axes of the xNAV and the vehicle axes are not the same as those listed in Table 8,
then they can be aligned by reconfiguring the xNAV for a different mounting
orientation using the NAVconfig software.
If the RT-Strut is being used to mount the xNAV in the vehicle then NAVconfig will
have to be used to configure the orientation or the xNAV will not work correctly. Page
23 gives more information on configuring the orientation of the xNAV in a vehicle.
Ethernet configuration
The xNAV communicates primarily via Ethernet. In order to communicate via
Ethernet, each xNAV is configured with a static IP address that is shown on the
delivery note. If the delivery note is unavailable, the default IP address normally takes
the form 195.0.0.sn—where snis the last two digits of the xNAV’s serial number. The
serial number can be found on the bottom of the xNAV or on the delivery note.

14
Oxford Technical Solutions
To transmit data between an xNAV and PC, the IP address of the PC must be in the
same range as the xNAV. We suggest configuring the PC with a static IP address in the
range 195.0.0.1 to 195.0.0.10 and a subnet mask of 255.255.255.0.
To change the IP address of the computer, follow these steps (applies to Windows
Vista/7/8):
1. Open the Control Panel from the Start menu.
2. In category view, select Network and Internet and then Network and
Sharing Center.
3. Select Change adapter settings in the side panel.
4. Right-click the Ethernet option and select Properties.
5. In the window that opens, navigate the list to find Internet Protocol Version 4
(TCP/IPv4). Select it and click Properties.
6. In the TCP/IPv4 Properties window (Figure 3), select Use the following IP
address and enter the IP address and subnet mask to use.
7. Click OK when finished.
Figure 3. Configuring the computer’s IP address

xNAV User Manual
Revision: 160412
15
Once the computer is configured the IP address of an xNAV can be found by running
NAVdisplay software; this will display the IP address of any system connected.
Note that it is possible to change the IP address of xNAV systems. If the IP address has
been changed then NAVdisplay should still be able to identify the address that the
xNAV is using as long as the PC has a valid IP address and this is not the same as the
xNAV’s.

16
Oxford Technical Solutions
Software installation
Included with every xNAV is a CD containing the software package NAVsuite. This
package contains a number of programs required to take full advantage of the xNAV’s
capabilities. Table 9 lists the contents of NAVsuite.
Table 9. Installed software components
Icon
Software
Description
Enginuity
Used to view real-time data from OxTS products via
Ethernet or a serial port. It can also be used to transmit
special commands and replay logged data. Note: Only the
xNAV5** models are capable of real-time outputs. Enginuity
will not display any data in real-time with the xNAV2**s.
NAVdisplay (beta)
Replacement for Enginuity. Features the same functionality
with an updated GUI and improved usability.
NAVconfig
Used to create, send, and receive configurations from OxTS
products. As configurations vary between products there is
no manual for NAVconfig. The options relevant to the
xNAV are covered in this manual on page 20.
RT Post-process
Used to download raw data files from the xNAV and post-
process the data. The configuration can be changed and
differential corrections can be applied before the data is
reprocessed. It can export NCOM, XCOM and CSV file
formats.
NAVgraph
Used to graph NCOM, XCOM and RCOM files created in
post-process. It can display graphs, cursor tables and map
plots and data can be exported in CSV or KML (Google
Earth) format.
Manuals
This folder contains PDF versions of relevant OxTS
manuals. Other manuals can be downloaded from the OxTS
website, http://www.oxts.com/support/manuals/.
To install NAVsuite, insert the CD and run NAVsetup.exe. Follow the onscreen
instructions to install the software. By default the installer creates the program files in
C:\Program Files (x86)\OxTS on 64 bit operating systems or C:\Program Files\OxTS
on 32 bit operating systems.
The first time some OxTS applications are run a firewall warning message similar to
that shown in Figure 4 may be triggered. This is because the program is attempting to
listen for, and communicate with, OxTS devices on the network. The firewall must be

xNAV User Manual
Revision: 160412
17
configured to allow each program to talk on the network, or programs will not work as
intended.
Figure 4. Windows Firewall warning message
A firewall warning message may be triggered the first time OxTS software is run. Access must be
allowed for each application that requires it, or the program cannot work properly. Sometimes a warning
will not be triggered but the firewall may still block certain functions. If a program fails to display the IP
address of a connected xNAV check the firewall settings for that connection.
Ensure both Private and Public networks are selected to ensure the software can
continue functioning when moving from one type to another.

18
Oxford Technical Solutions
Hardware installation
Installing the xNAV is not difficult, but it is a precision instrument and care should be
taken not to subject it to extreme shock, vibration or temperature. Bear in mind the
minimum clearance required for the antenna connectors and user cable is 39 mm from
the front panel (see Figure 5).
Figure 5. Clearance required for connectors and user cable
When mounting the xNAV a minimum of 39 mm is required for the user cable. At the minimum
distance, it will not be possible to remove the main connector without also uninstalling the xNAV.
The xNAV does not need to be located at the desired measurement point as the outputs
can be displaced using NAVconfig. However, any displacement should try to be kept to
a minimum. Once configured, the xNAV’s output will appear the same as if it was
mounted at the displaced location.
It is essential to install the xNAV rigidly in the vehicle. It should not be able to move or
rotate compared to either GNSS antenna, otherwise the performance will be reduced.
The xNAV is compatible with the RT-Strut product from OxTS when used with
additional mounting brackets. The RT-Strut can be used to provide a quick and secure
vehicle mounting option.
The orientation of the xNAV’s local axes is shown on page 13. For ease of use it is best
to try and mount the xNAV so its axes are aligned with the vehicle axes. If the system
must be mounted misaligned with the vehicle then the offsets must be measured and
entered into NAVconfig. This allows the outputs to be rotated based on the settings
entered to transform the measurements to the vehicle frame.
Antenna placement and orientation
The placement and orientation of the GNSS antennas is important to the system
accuracy. For optimal performance it is essential for the antennas to be mounted where
they have a clear, uninterrupted view of the sky and on a suitable ground plane, such as
the roof of a vehicle. For good multipath rejection the antennas must be mounted on a
metal surface using the magnetic mounts provided; no additional gap may be used.
The antennas cannot be mounted on non-conducting materials or near the edges of
conducting materials. If the antennas are to be mounted with no conductor below them

xNAV User Manual
Revision: 160412
19
then different antennas must be used. It is recommended to mount the antennas at least
20 cm from any edge where possible.
Antennas should be spaced between 1 m and 5 m apart and the antenna baseline should
be aligned with one of the vehicle axes where possible, either inline or perpendicular to
the vehicle’s forward axis. It is possible to use a shorter antenna separation but the
heading accuracy will degrade.
When mounting the antennas, the secondary antenna should be mounted in the same
orientation as the primary, as shown in Figure 6. The direction the cable exits the
antennas does not matter as long as it is the same for both.
Figure 6. Antenna placement
A) The bases of the antennas are parallel, but the cables exit in different directions. B) The cables exit in
the same direction but the bases of the antennas are not parallel. C) The bases of the antennas are parallel
and the cables exit in the same direction. This configuration will achieve the best results.
When measuring the antenna separation, if the antennas are level (i.e. within 15° of
horizontal) then the separation should be measured to within 5 cm. If the antennas are
not level then the separation must be measured to 5 mm.

20
Oxford Technical Solutions
Configuring the xNAV
To obtain the best results from your xNAV it will be necessary to configure it to suit
the installation and application before using it for the first time. The program
NAVconfig can be used to do this. This section describes how to use NAVconfig and
gives additional explanations on the meanings of some of the terms used.
It is only possible to change the xNAV configuration using Ethernet. It is necessary to
have the Ethernet on your computer configured correctly in order to communicate with
the xNAV and change the settings. See the section “Ethernet configuration” on page 13
for more information.
The configuration file defines where the xNAV is and how it is orientated in relation to
the host being measured. It also specifies any options to use while processing the data.
Once a configuration has been committed to the xNAV, it will remain there and the
system will use that configuration each time on start up. There is no need to reconfigure
it unless the xNAV or an antenna is moved.
Selecting the operating language
The NAVconfig software can operate in several languages. To change language, select
the language from the drop-down menu at the bottom of the page. The language is
“hot-swappable” making it easy and fast to switch between languages.
The software will use the regional settings of the computer to choose whether numbers
are represented in the English or European format (dot or comma for the decimal
separator). The selected language does not change the format used for numbers.
Navigating through NAVconfig
NAVconfig provides a ten-step process to make configuring your product as easy as
possible. After completing each step, click the Next button at the bottom of the window
to proceed to the next step. The Back button can be used to return to the previous step
at any time. Clicking Cancel will bring up a warning asking to confirm you want to
close the wizard and lose any changes you have not saved.
To quickly move between any of the steps, click on the step name in the sidebar to
instantly jump to that page.
Measurements are always displayed in metric units in NAVconfig. However, when
entering measurements alternate units can be used as long as they are specified, e.g. 10″
or 10 in. NAVconfig will then convert and display these in metric units.