NOTE: This repository is related with the next scientific work:

Barral, V.; Escudero, C.J.; García-Naya, J.A.; Maneiro-Catoira, R. NLOS Identification and Mitigation Using Low-Cost UWB Devices. Sensors 2019, 19, 3464.https://doi.org/10.3390/s19163464

If you use this code for your scientific activities, a citation is appreciated.

README

This repository includes several tools and ROS nodes to process TOA (Time Of Arrival) measurements coming from Decawave EVK1000/TRECK1000 or Pozyx tags and anchors.

The nodes included in the repository are:

• anchors This node reads the 3D positions of a set of anchors from an .xml file and publish them in the ROS environment to be read by other nodes.
• dwfixer This node receives measurements from a Decawave EVK1000/TRECK1000 tag and applies a bias correction (See Assessment of UWB Ranging Bias in Multipath Environments ). Finally it publishes the result in a new message of type gtec/Ranging.
• pozyxfixer This node receives measurements from a Pozyx tag and parses them to extract the information and to publish it as a new gtec/Ranging message.

Dependencies

GTEC ROS TOA package has the next dependencies:

• gtec_msgs Another GTEC ROS project with a set o custom messages definitions. Available here.
• Boost library. http://www.boost.org
• Armadillo library http://arma.sourceforge.net

Building the nodes

To build the nodes, source code must be cloned inside a catkin work space on a ROS installation (see Creating a workspace for catkin). If the catkin work space is located at ~/catkin_ws then:

$ cd ~/catkin_ws/src
$ mkdir gtec
$ cd gtec
$ git clone rostoa

Then catkin_make must be used to build the nodes:

$ cd ~/catkin_ws
$ catkin_make

Launching the nodes

There are several .launch files in the project to launch the nodes using the roslaunch command.

Launching anchors node:

$ roslaunch gtec_rostoa anchors.launch

Launching dwfixer node:

$ roslaunch gtec_rostoa dwfixer.launch

Launching pozyxfixer node:

$ roslaunch gtec_rostoa pozyxfixer.launch

Nodes configuration

Each node has different configuration parameters. Some of them are set through a .xml file while others are set in the .launch.

Anchors node

There is an anchors.xml file inside ~/catkin_ws/src/gtec/rostoa/config that defines the number and position of each anchor. The content of this file looks like:

<config>
 <anc ID="0" label="A0" x="2.129" y="6.114" z="1.652"/>
 <anc ID="1" label="A1" x="4.00" y="0.361" z="1.765"/>
 <anc ID="2" label="A2" x="7.327" y="6.478" z="1.752"/>
 <anc ID="3" label="A3" x="8.351" y="0.361" z="1.765"/>
 <anc ID="4" label="A4" x="12.513" y="2.886" z="1.834"/>
</config>

DWFixer node

Parameters of DWFixer node are set in the ~/catkin_ws/src/gtec/rostoa/dwfixer.launch file:

        <param name="useCustomBiasFix" type="bool" value="true" />
        <param name="customBiasFixMode" type="int" value="3" />
        <param name="cableLength" type="double" value="0.4" />
        <param name="tableBiasLOS" value="$(find gtec_rostoa)/src/rostoa/config/tableBiasLOS.csv"></param>
        <param name="tableBiasLOSError" value="$(find gtec_rostoa)/src/rostoa/config/tableBiasLOSError.csv"></param>
        <param name="tableBiasNLOSFP" value="$(find gtec_rostoa)/src/rostoa/config/tableBiasNLOSFP.csv"></param>
        <param name="tableBiasNLOSFPError" value="$(find gtec_rostoa)/src/rostoa/config/tableBiasNLOSFPError.csv"></param>

• useCustomBiasFix: if true the custom bias fix is applied.
• customBiasFixMode: different custom bias fix modes are available. Possible values are:
  • 0 Uses a scenario of LOS
  • 1 Uses a scenario of NLOS
  • 3 Auto mode, switch from one scenario to other according to some quality parameters.
• cableLength: length in meter of the connection cable between the tag and the computer that receives the data. This length must be taken into account because it introduces a delay that must be corrected.
• tableBiasLOS, tableBiasLOSError, tableBiasNLOSFP, tableBiasNLOSFPError: are a set of .csv files with real measurements of Decawave chips that are used by the node to correct the bias in the ranging estimation.

PozyxFixer

Parameters of PozyxFixer node are also set in the launch file located at ~/catkin_ws/src/gtec/rostoa/pozyxfixer.launch

<param name="numAnchors" type="int" value="6" />
<param name="cableLength" type="double" value="0.0" /

• numAnchors: the number of anchors to receive measurements from. Measurements from anchors with ids greater that this number will be ignored.
• cableLength: length in meter of the connection cable between the tag and the computer that receives the data. This length must be taken into account because it introduces a delay that must be corrected.