Manual

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4.2 Mobile beacon (“hedgehog”)
- The mobile and stationary beacons can be easily interchanged by selecting the
option in the Dashboard
- The mobile beacons designed placed on
a robotic vehicle, copter/drone, 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 taken into
account in the robot’s software (SW).
- It’s recommended to place the mobile
beacon horizontally to provide optimal
ultrasonic coverage in the upper
hemisphere.
- Its sensors must not cover with anything
that can reduce the strength of ultrasonic
signal. For example, the system won’t
normally work if one puts the mobile
beacon in a plastic box
- The beacon’s coordinates are updated according to the rate set on the
Dashboard.
- The system may contain one or several mobile beacons. Current implementation
relies on a time-division multiple access approach. Thus, if two mobile beacons
are activated they share the same system bandwidth. It means that, if the 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 may contain
different solution that will improve update rates in setups with multiple mobile
beacons
- Location data is obtained either from the “hedgehog” via USB (virtual UART),
UART, SPI, or from the modem/router via USB (virtual UART). More information
on interfaces can be found here
- Data from the beacon sent in a streaming format identical to that of GPS (NMEA
0183)
- There are 433MHz and 915MHz versions 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.: