OXTS RT-Backpack User manual

User Manual
RT-Backpack
Vehicle-to-pedestrian
tracking

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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.
Revision
Document Revision: 210303 (See Revision History for detailed information).
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]

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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.
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.

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Contents
Legal notices .......................................................................................................................................1
Copyright notice...................................................................................................................................1
Revision...............................................................................................................................................1
Contact details.....................................................................................................................................1
Warranty..............................................................................................................................................2
Environmental protection.....................................................................................................................2
System overview.....................................................................................................................................4
Scope of delivery.....................................................................................................................................4
Specification............................................................................................................................................5
Assembly instructions .............................................................................................................................5
Configuring the RT-Backpack.................................................................................................................6
NAVconfig settings..............................................................................................................................6
NAVconfig Options.........................................................................................................................11
RT-Range Settings............................................................................................................................11
Initialisation and warm-up .....................................................................................................................12
Charging the battery..............................................................................................................................12
Using the RT-XLAN...............................................................................................................................12
Configuration.....................................................................................................................................13
Operation...........................................................................................................................................13
LED indicators................................................................................................................................13
Checking the communication link......................................................................................................14
Revision history.....................................................................................................................................14

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System overview
The RT-Backpack is a collection of small and lightweight components that transform any RT sensor
into a wearable RT-Range target object. This makes it ideal for testing and validating advanced driver
assistance systems (ADAS), especially where there is a need to track pedestrians, cyclists or
motorcyclists.
While the RT-Backpack is packaged differently, the principal of operation is the same as an
RT-Range target. RT-Range hunters do not differentiate between data received from target
RT-Ranges or RT-Backpacks and treat both as mobile targets. For that reason, only information
unique to the RT-Backpack is covered in this manual. All other relevant information can be found in
the RT-Range manual.
Scope of delivery
Table 1 lists all standard items delivered with the RT-Backpack. Table 2 lists optional components.
Table1.StandardRT-BackpackComponents
Qty
Description
1
Backpack
1
Frame including fasteners
1
50 cm pole including fasteners
1
RT Backpack bolt pack –Qty 5 x M4x8 hex bolts & washers, 3 mm & 4 mm hex key
1
Survey grade antenna for multi-path rejection
1
1 m TNC-TNC GPS antenna cable
1
7 Ah, 12-volt battery
1
14C0077B user cable
1
RT-XLAN (client) wireless LAN radio and PoE cable
1
2.4 GHz antenna
1
Base-to-antenna extension pole and L bracket (RT-XLAN)
1
Wiring harness
1
Mains powered battery charger
1
RT-Backpack user manual
Table2.OptionalRT-BackpackComponents
Qty
Description
1
Radio modem for DGPS signals (country specific)
1
Radio antenna (country specific)

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Specification
Table3.RT-BackpackTechnicalSpecifications
Parameter
Specifications
RT-XLAN Radio Range—Line of Sight (m)
>500
RT-XLAN Delay (ms) RMS
<10
Temperature Range (°C)
-10 to 50
Dimensions (mm)
340 × 270 × 180
Mass (kg)
5
Assembly instructions
Assembly of the RT-Backpack is not complicated but requires care to avoid damaging components.
Please follow this process while referring to the diagram in Figure 1:
1. Use 3 mm hex driver to screw the three M4 × 8 mm cap head screws into the RT (leaving the
top left hole free. The screws should be tightened firmly to prevent movement, but not overly
tight. Mount the RT sensor [3] in the frame [4] by sliding the RT over the side rails until the
three bolts fit snugly into their housing. Screw the remaining thumb screw through the hole on
the side and then tighten the remaining hex screws to secure the RT. For non-permanent
installations the RT sensor can be mounted using only three screws as access is restricted to
the screw nearest the main switch in the frame.
2. If the optional DGPS radio [2] is being used for differential corrections, this should be fitted
using the supplied hook and loop strips. Push one of the strips, hook-side towards the RT,
through the furthest slot from the edge and pull as far through as you can. Push the end back
through the slot closest to the edge of the frame. Place radio with the TNC connector at the top
on the bracket and secure with the hook and loop strap.
3. Use the U-bolts and dome head nuts to fix the mounting pole and antenna [1] into the frame
with a 10 mm spanner. A flat washer and spring washer should be fitted under each nut. Attach
one end of the antenna cable to the antenna. Ensure the frame is inside the bag before sliding
the antenna pole through both U-Bolts and the corresponding hole in the backpack until it
reaches the base. The hole in the backpack is narrow so the antenna cable should also be
pushed through at the same time. Tighten the dome head nuts when the antenna pole is in
place. The supplied antenna may differ from the one shown in the diagram but will provide
equivalent or superior performance.
4. The user cable can now be connected. Start by attaching it to the RT sensor. Route the other
wires carefully through the frame to their respective components. This is clearly marked on the
loom. The ethernet connector should be connected to the LAN port of the front connector.
5. The RT-XLAN power cable should also be connected to the DC connector and the rear M12
connector next to the battery. Connect the power cable to the battery [5]. Connect the positive
terminal first, then the negative one. Connect the radio aerial to the radio’s TNC connector and
push through the corresponding hole in the backpack. Lastly, connect the antenna cable to the
RT’s primary antenna connector.

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6. The frame front plate [6] can now be attached to the main frame using four M6 × 12 mm button
head screws.
7. Attach the base of the RT-XLAN to the antenna through the bracket. Screw the similar black
plastic bracket to the front of the front plate. Lift the hole in the front of the backpack over the
RT-XLAN bracket and then attach the extension pole to the bracket. The RT-XLAN [7] should
be attached to the Base-to-Antenna Extension Pole fixed to the boss on the frame front plate.
The RT-XLAN can then be height adjusted for maximum performance.
8. The RT-Backpack is turned on using the toggle switch mounted near the top of the RT sensor.
NB: this switch is located under the charging point [3].
Figure1.AssemblyoftheRT-Backpack
Configuring the RT-Backpack
NAVconfig settings
Some RT models have different options. These are set when the correct model is selected in Step 1
of NAVconfig (Figure 2). Settings can be prepared in advance as NAVconfig does not require a
device to be connected.

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Figure2.NAVconfigStep 1-ProductSelection
A predefined setting for the RT-Backpack is included with NAVconfig. This is normally located at
C:\Program Files (x86)\OxTS\RT-Range\RT-Back. Use the Read Settings from a Folder option to
locate it. See Figure 3.
Figure3.NAVconfigStep 2-ReadConfiguration
In an RT-Backpack application the y-axis always points left and the z-axis always points forwards
(Figure 4). This is set automatically from the predefined settings file.

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Figure4.NAVconfigStep 3-Orientation
The primary antenna measurements will be read from the predefined settings file when used (Figure
5). It is important to re-check the “Above”measurement as the antenna pole may be set to a different
height (z-axis) to the one used in the settings file.
Figure5.NAVconfigStep4-PrimaryAntenna
The RT-Backpack does not use dual antennas, so make sure that option is disabled (Figure 6).

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Figure6.NAVconfigStep5-SecondaryAntenna
The advanced slip option (Figure 7) is not applicable to the RT-Backpack. Ensure it is disabled.
Figure7.NAVconfigStep6-Advanced Slip
Several settings should be checked on the options page (Figure 8). Most importantly, Displace Output
should be disabled. The RT-Range applies any displacement. For a full explanation of options see
NAVconfig Options on page 11.

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Figure8.NAVconfigStep7-Options
Before committing any settings (Figure 9), make sure the correct RT is selected as several may be
available on the network.
Figure9.NAVconfigStep 8-Commit
It is not necessary to save a copy of any settings (Figure 10) as they can be read from the device
using NAVconfig. Several files are created when saving settings, so it is best to create a new folder
for each set.

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Figure10.NAVconfigStep9-Save/Finish
NAVconfig Options
Many of the options available in step 7 of NAVconfig do not apply when configuring an RT-Backpack.
Most default options are suitable with the exception of heading lock, which should be disabled. Only
the settings listed here should be reviewed. Care should be taken when reading an existing
configuration from the RT device, or using a saved configuration in case settings have been changed
accidentally.
▪GPS environment—change this to suit the operating environment. An RT sensor will only
achieve accuracies that meet its specification in open-sky mode.
▪Differential—when using radio modem DGPS corrections, these need setting. See the
Differential Correction Option section of the RT Manual.
−SBAS—see SBAS Option section of RT manual.
−OmniSTAR—see OmniSTAR Option section of RT manual.
▪Heading Lock—this must be disabled in an RT-Backpack application.
▪Initialisation Speed—this should be set to the speed of a brisk walk (1 m/s). After initialisation,
this value has no effect on the output.
▪Displaced Output—this must be disabled. The hunter RT-Range applies any offsets so any
value entered here will cause an error at the RT-Range.
RT-Range Settings
Because the hunter RT-Range does not differentiate between RT-Backpack and RT-Range target
objects, the RT- Backpack can be configured in the same way as normal RT-Range targets. See the
RT-Range manual for details.

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Initialisation and warm-up
To initialise the RT-Backpack exceed the “initialisation speed” specified in NAVconfig Options (Page
11). It is important to walk forwards and in a straight line the first time the initialisation speed is
exceeded.
Figure11.OperatingtheRT-Backpack
It is important not to spin too quickly when wearing the RT-Backpack as this can saturate the gyros.
The RT sensor is designed to work on vehicles, boats and aircraft. Humans can spin much faster and
therefore exceed the operating thresholds of the sensors. Care should also be taken when donning
the backpack for the same reason. If the specification of the gyros is exceeded, the RT may need to
be reset and go through the initialisation and warm-up process again.
Data from the RT-Backpack can also be monitored in the RT-Range software, using the Real-time
display window. A full explanation of this can be found in the RT-Range manual in the Real-time
display section. It is worth noting that even though the RT-Backpack is transmitting data to the
RT-Range, it does not mean the RT-Backpack has achieved its expected accuracy, and care should
be taken to check this before any test commences.
During tests it is quite feasible for the person wearing the RT-Backpack to monitor its status using
NAVdisplay and a laptop PC connected wirelessly to the relevant RT device. Doing this will not affect
the performance of the RT-Backpack or the data being broadcast to the hunter RT-Range device.
Charging the battery
The RT-Backpack is supplied with a maintenance-free, rechargeable lead acid battery and mains-
powered charger. In ideal conditions the battery should provide approximately three-to-four hours of
use before needing a charge—although it is advisable to start any test with the battery in a fully
charged state.
While it is impractical to walk around with the RT-Backpack while charging, configuration changes or
bench-tests can be conducted while the system charges. The battery can be charged without
powering down the RT-Backpack.
Using the RT-XLAN
The RT-XLAN in the RT-Backpack will come pre-configured as a “client” and will be ready to be used
as a target.

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For more information about the RT-XLAN please refer to the RT-XLAN user manual which is available
at https://support.oxts.com/hc/en-us/categories/115000374665-Products
Configuration
There are no user configuration options on the RT-XLAN. However, it is important to make sure that
each unit is compatible with the other units in the environment. There are several items to consider.
▪Each RT-XLAN will have a label showing its configuration.
▪The RT-XLAN labelled “Base” should be used on the Hunter vehicle.
▪The RT-XLAN labelled “Client” should be used on the Target vehicle.
▪There must be an RT-XLAN base unit. The RT-XLAN client units will not communicate with
each other unless there is a base present.
▪There cannot be two RT-XLAN base units in the same environment.
▪Each RT-XLAN has an IP address. All the units being used must have different IP addresses.
Normally the IP address will be in the range from 195.0.0.170 to 195.0.0.175. It is possible to
order different IP addresses from OxTS. This IP address range should not conflict with the
recommended IP addresses of other OxTS equipment.
▪The RT-XLAN will be configured for use in a specific country. Different licensing laws require
different frequencies to be used in different countries. RT-XLAN units from one country cannot
be used automatically with RT-XLAN units from another country.
It is possible to change the configuration in the field, but it is necessary to contact OxTS support for
information on how to do this. If any configuration is changed then make sure the stickers on the
outside of the RT-XLAN are changed to reflect the configuration changes made.
Operation
Once everything is connected the RT-Range can be powered up. The RT-XLAN should work
automatically and the RT-Range can be used as normal.
LED indicators
Found on the side of the RT-XLAN are a series of LEDs. These provide a quick indication of the
status of the RT-XLAN without the need for any software.
The meanings of these LEDs are shown in Table 4.
Table4.LEDindicators
LED Label
Description
Power
Power on
<···>
Link established
Shows the strength of the signal across four LEDs
The signal strength indicator is a very useful tool for quickly checking the vehicle-to-vehicle signal
strength before attaching a PC to the RT-Range system.

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Checking the communication link
It is possible to check that the communication link is working and there are several ways to do this.
▪It should be possible to “ping” the IP address of the RT-XLAN. This can be pinged first on the
Ethernet side (i.e. without any wireless communication) and then on the remote side (i.e.
through one RT-XLAN to another).
▪If the RT-XLAN is working, then packets from RT systems should be visible from any “node”.
NAVdisplay can be used to receive the packets.
▪The LED indicators on the RT-XLAN will provide a quick indication of a communication link and
the strength of the signal - as shown in Table 4.
Revision history
Table5.Revisionhistory
Revision
Comments
130208
Initial version.
141027
Revised for RT-XLAN changes
180222
WEEE update
210303
Updated throughout.

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