Operation Manual

97
- Example of proper positioning of the mobile beacon can be found here:
https://youtu.be/PFgNPkLGCDk
- The beacon is placed horizontally and above other objects that can cast a shadow
on the stationary beacons
- Keep the radio signal’s strength under control
- The RSSI (Dashboard => right menu) of any beacon/modem must not be higher
than -25dBm. Otherwise, the system may malfunction
It is recommended the distance between the modem and beacons be no less than
0.5–1m. Beacons can be placed as close to each other as needed. If a beacon is
extremely close to the modem, disconnect the antenna from the beacon. Monitor
the Received Signal Strength Indicator (RSSI). It must be in the range of -25 to -
70dBm. An RSSI of less than -70dBm will work too, but packet losses may start
occurring. The quality of the radio connection very much depends on external
interference as well because the used band is ISM (either 915MHz or 433MHz)
and there are numerous co-existing systems.
Use 30 - 50 periods (pulses) in settings instead of the default 5. Select:
Ultrasound settings => Number of periods
When you have large errors in position estimation (more than a 1m inaccuracy),
use the embedded Oscilloscope on Dashboard => View to determine which
stationary beacon is jammed
Reduce the gain of the ultrasonic manually depending on your system
- Multibyte numbers are transmitted starting from low byte (little endian
format)
- Negative values represented as two's complement
For example:
- a 32-bit integer value '-100' is represented as FFFFFF9C (transmitted as sequence
9C, FF, FF, FF in little endian format)
- This value is detected as negative by '1' value of MSB and converted by
subtracting 2^32: 0xFFFFFF9C- 0x100000000 = -0x64= -100.