# DroneCAN Messages
The ARK Flow MR outputs data using the DroneCAN protocol\
\
\
There are 3 onboard sensors with a corresponding message each. Optical Flow and Rangefinder data publishing is enabled by default. IMU data publishing must be enabled by setting the node parameter CANNODE\_PUB\_IMU.
* Optical Flow: `com.hex.equipment.flow`
* Rangefinder: `uavcan.equipment.range_sensor`
* IMU: `RawIMU`
There are also messages all Nodes emit:\
* NodeStatus: `NodeStatus`
* GetNodeInfo: `GetNodeInfo`
#### Messages
The DroneCAN messages can be found here:
{% embed url="" %}
***
### `com.hex.equipment.flow`
#### `Measurement`
Full name: `com.hex.equipment.flow.Measurement`
Default data type ID: 20200
```
float32 integration_interval # Integration Interval in seconds
float32[2] rate_gyro_integral # Integrated Gyro Data in radians
float32[2] flow_integral # Integrated LOS Data in radians
uint8 quality # Flow Data Quality Lowest(0)-Highest(255) Unitless
```
***
### `uavcan.equipment.range_sensor`
#### `Measurement`
Full name: `uavcan.equipment.range_sensor.Measurement`
Default data type ID: 1050
```
#
# Generic narrow-beam range sensor data.
#
uavcan.Timestamp timestamp
uint8 sensor_id
uavcan.CoarseOrientation beam_orientation_in_body_frame
float16 field_of_view # Radians
uint5 SENSOR_TYPE_UNDEFINED = 0
uint5 SENSOR_TYPE_SONAR = 1
uint5 SENSOR_TYPE_LIDAR = 2
uint5 SENSOR_TYPE_RADAR = 3
uint5 sensor_type
uint3 READING_TYPE_UNDEFINED = 0 # Range is unknown
uint3 READING_TYPE_VALID_RANGE = 1 # Range field contains valid distance
uint3 READING_TYPE_TOO_CLOSE = 2 # Range field contains min range for the sensor
uint3 READING_TYPE_TOO_FAR = 3 # Range field contains max range for the sensor
uint3 reading_type
float16 range # Meters
```
***
#### `RawIMU`
Full name: `uavcan.equipment.ahrs.RawIMU`
Default data type ID: 1003
```
#
# Raw IMU data with timestamps.
#
# THIS DEFINITION MAY BE CHANGED IN A NON-BACKWARD-COMPATIBLE WAY IN THE FUTURE.
#
#
# Data acquisition timestamp in the bus shared time base.
#
uavcan.Timestamp timestamp
#
# Integration interval, seconds.
# Set to a non-positive value if the integrated samples are not available
# (in this case, only the latest point samples will be valid).
#
float32 integration_interval
#
# Angular velocity samples in radian/second.
# The samples are represented in the body frame, the axes are ordered as follows:
# 1. angular velocity around X (roll rate)
# 2. angular velocity around Y (pitch rate)
# 3. angular velocity around Z (yaw rate)
#
float16[3] rate_gyro_latest # Latest sample, radian/second
float32[3] rate_gyro_integral # Integrated samples, radian/second
#
# Linear acceleration samples in meter/(second^2).
# The samples are represented in the body frame, the axes are ordered as follows:
# 1. linear acceleration along X (forward positive)
# 2. linear acceleration along Y (right positive)
# 3. linear acceleration along Z (down positive)
#
float16[3] accelerometer_latest # Latest sample, meter/(second^2)
float32[3] accelerometer_integral # Integrated samples, meter/(second^2)
#
# Covariance matrix. The diagonal entries are ordered as follows:
# 1. roll rate (radian^2)/(second^2)
# 2. pitch rate (radian^2)/(second^2)
# 3. yaw rate (radian^2)/(second^2)
# 4. forward acceleration (meter^2)/(second^4)
# 5. rightward acceleration (meter^2)/(second^4)
# 6. downward acceleration (meter^2)/(second^4)
#
float16[<=36] covariance
```
---
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