Operation Manual
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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
- It is recommended to place the mobile
beacon horizontally to provide optimal
ultrasonic coverage in the upper
hemisphere
- Its sensors must not be covered with
anything that can reduce the strength of
ultrasonic signal. For example, they
system wouldn’t normally work, if one puts
the mobile beacon in a plastic box
- The beacon’s coordinates are updated
according to the rate set in the Dashboard
- System may contain one or several mobile
beacons. Current implementation relies on
time division multiple access approach.
Thus, if two mobile beacons are activated, they share the same system bandwidth. 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 may 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 or
the modem/router via USB (virtual UART). 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 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: http://www.marvelmind.com/#Interfaces