9
3.4.2
Mobile beacon (“hedgehog”)
-
The mobile and stationary beacons can be easily interchanged by selecting the
option
in the
Dashboard
-
The mobile beacons are designed to be placed on the robot vehicle or copter/drone or AGV
or helmet to trace its location. Formally speaking, location of the mobile beacon is traced –
not the robot itself. Since the sizes and the location of the central point of the mobile beacon
and the robot are different, the difference
has be taken into account in the robot’s
SW
-
The mobile beacon has to be placed
horizontally to provide optimal ultrasonic
coverage – upper hemisphere
-
Its sensors must not be closed with
anything that can reduce the strength of
ultrasonic signal
-
The beacon’s coordinates are updated
according to the rate set in the Dashboard
-
System may contain one or more mobile
beacons. Current implementation relies on
time division multiple access approach.
Thus, if two mobile beacons are activated,
they share the time. It means that, if 16 Hz
update rate is selected and there are 2
mobile beacons in the system, each beacon’s location will be updated with the rate of
16Hz/2 ~ 8Hz. If there are 3 mobile beacons => 16Hz/3 ~ 5Hz, etc. Future SW
implementation will contain different solution that will improve update rate in the setup with
multiple mobile beacons.
-
Location data is obtained either from the “hedgehog” via USB (virtual UART), UART, SPI.
More on interfaces:
http://www.marvelmind.com/#Interfaces
-
Data from the beacon is sent in a streaming format identical that of GPS (NMEA 0183)
-
There is 915MHz version available. Proprietary radio protocol is used for communication
and synchronization
-
The “hedgehog” has been successfully integrated with Windows PC, Linux machines,
Raspberry Pi, Arduino boards, Intel boards, etc:
http://marvelmind.com/pics/supported_interfaces.png
