Products
-
-
- Accessories
- Breakout boards
This is an old revision of the document!
Alpha production Currently this product is only available as part if our alpha release and not yet finalized. Information here will be changed at any time without notice.
The local positioning system is based on the DecaWave DWM1000 module. The system consists of a number of anchors that's continuously pinged from the Crazyflie 2.0 deck that's based on the same module. The anchors are placed around the room at known positions (for now).
Our testsystem uses the following components:
Here's a video of the current state (March 2016).
The hardware consists two parts, nodes and decks.
The firmware for the DWM deck is included in the Crazyflie 2.0 firmware build (recent) and activated when the deck is attached. The deck contains a small memory that holds the address of the board as well as the addresses of the anchors it will use for ranging.
More information on building the firmware and the firmware itself can be found here.
The ROS module for positioning with the LPS is available on Github: https://github.com/bitcraze/lps-ros. It has been developed and tested on ROS Indigo running on Ubuntu 14.04
To get started from a newly installed ubuntu:
The position of the anchor has to be entered in a configuration file. The file should be data/anchor_pos.yaml. An example is present in the data folder:
n_anchors: 6 anchor0_pos: [ 0, 0, 1.85] anchor1_pos: [ 0, 2, 1.85] anchor2_pos: [ 4, 2, 1.85] anchor3_pos: [ 4, 0, 1.85] anchor4_pos: [1.3, 1, 1.85] anchor5_pos: [2.6, 1, 1.85]
The positions are in meter, [x, y, z], from the origin.
When this file is configured, the dwm_loc.launch launch configuration will connect the crazyflie with the right log setup, launch the particle filter and the visualization:
$ roslaunch bitcraze_lps_estimator dwm_loc.launch uri:=radio://0/40/2M
the dwm nodes can be configured in 3 different modes; tag, anchor or sniffer. By default they come pre-configured as anchors. The anchors are powered with 5v either through micro usb, power jack or screw terminal A nice way to power the anchors is to use usb power pack like we do here:
Place the anchors at least 15 cm from the floor/wall/ceiling, and preferably at least 2 meter apart. We use 3d printed anchor-stands that can be found at: https://github.com/bitcraze/bitcraze-mechanics/blob/master/LPS-anchor-stand/anchor-stand.stl
One of the main consideration for the anchor placement is the Dilution Of Precision.