ros_dwm1000

ROS Indoor/Outdoor Positioning System based on Decawave's DWM1000 Ultra Wide Band transceivers. The whole system was tested indoors with 3 anchors and 1 tag. Technically this should work outdoors as well.

Hardware

Both anchors and tags use the same circuit board. The board houses the UWB transceiver, an Arduino Pro Mini 3.3V and a built-in USB Male so you can plug it straight to a power bank and deploy the anchors remotely.

If you wish to fabricate the PCB, the Gerber files are included /hardware/pcb/fabricate. Seeedstudio's DRU for 2-layer board was used to verify the design.
The DWM1000 Arduino library uses random address for the anchors and doesn't support arbitrary addresses. You need to edit https://github.com/grassjelly/ros_dwm1000/blob/master/hardware/firmware/anchor/lib/DW1000/DW1000Ranging.cpp#L166-L167 every time you upload the anchor codes to have unique address per anchor from:
```
_currentShortAddress[0] = random(0, 256);
_currentShortAddress[1] = random(0, 256);
```
to the address you want (ie. address: '01'):
```
_currentShortAddress[0] = 1;
_currentShortAddress[1] = 0;
```

Installation

Install dependencies

$ pip install localization
$ pip install scipy
$ pip install shapely

Install map_server

$ sudo apt-get install ros-indigo-map-server

Build the package
```
$ cd ~/catkin_ws
$ catkin_make
```

Defining TF

You need to define the transforms from map to each anchor's frame. You can run map_server and load your map to identify the exact points you want your anchors placed. Open RVIZ and click on the location of each anchor by using "Publish Points".
Once you get the exact location of each anchor, add the transforms in /launch/tf.launch file. Take note that the frame_id of each anchor must be the same as the address defined in Arduino (_currentShortAddress[]).

Usage

Run localize.launch:
```
$ roslaunch ros_dwm1000 localize.launch
```

Parameters

serial_port(default: '/dev/ttyUSB0')

Tag's serial port.

frame_id(default: 'uwb_tag')

Tag's frame_id when transform's published from map to tag.

req_anchor(default: 3)

The mininum number of anchors the system must find before performing trilateration between anchors. Increase this if you want to improve the accuracy. This can be tweaked down to a minimum of 2 anchors. Each tag can only support up to 4 anchors now.

min_range(default: 0.5)

The minimum probable distance from an anchor to a tag to prevent false reading. For example, if your anchor is hanging 1 m away from the floor, it makes sense to put 1 meter as minimum range since there's no way it will range less than 1 meter.

max_range(default: 10.0)

The maximum probable distance from an anchor to a tag to prevent false reading. For example, if your anchors are placed in 8 meter x 8 meter room, you can set the max_range less than or equal the hypotenuse of the room since ranges won't get any longer than that.

albertkasdorf / ros_dwm1000