27
ORIENT_Type (quaternion)
When this packet type is chosen, the node samples the sensors, applies the internally stored calibration
and computes the orientation of the device using one of the available algorithms. The orientation is
represented in quaternion form and represents the orientation of the device with respect to a local earth
fixed frame. The node’s body reference frame is the one illustrated in Figure 1, and the earth default
reference frame has x pointing north, y pointing west and z pointing upwards (NWU
– North-West-Up).
An alternative reference frame can be chosen (NED
– North-Est-Down).
Byte 0
Byte 1
Byte2
Byte3 .. Byte6
Byte7 .. Byte10
Byte11 .. Byte14
Byte15 .. Byte18
Byte19
0x20
PKT_ID
Pkt_count
q0
q1
q2
q3
CHECKSUM_XOR
Packet Header:
the first packet byte is always
0x20
PKT_ID:
the identifier for the packet type. For the orientation data packet it’s
0x0C
PKT_COUNT:
progressive
packet number ranging from 0 to 255
q0
– q3:
the orientation of the device expressed in quaternion form. Each one of the components
is a 32-bit floating point number in the IEEE 754 standard. The four bytes are organized as
follows:
Byte3
Byte4
Byte5
Byte6
Byte 0
Byte 1
Byte 2
Byte 3
IMPORTANT: The CHECKSUM is calculated as XOR of previous Bytes
VBATT (Battery Voltage)
This packet reports the battery voltage in mV.
It is sent periodically (typically every 5 seconds) if SEND_BATTERY (address 0x4F) is set to 1.
Byte 0
Byte 1
Byte2
Byte3
Byte4 .. Byte14
Byte15
0x20
0xBA
Vbatt_L
Vbatt_H
0
CHECKSUM_XOR
IMPORTANT: The CHECKSUM is calculated as XOR of previous Bytes