# VehicleAirData (UORB message)

[source file](https://github.com/PX4/PX4-Autopilot/blob/main/msg/VehicleAirData.msg)

```c

uint64 timestamp            # time since system start (microseconds)

uint64 timestamp_sample     # the timestamp of the raw data (microseconds)

uint32 baro_device_id       # unique device ID for the selected barometer

float32 baro_alt_meter			# Altitude above MSL calculated from temperature compensated baro sensor data using an ISA corrected for sea level pressure SENS_BARO_QNH.
float32 baro_pressure_pa		# Absolute pressure in Pascals
float32 ambient_temperature		# Abient temperature in degrees Celsius
uint8 temperature_source		# Source of temperature data: 0: Default Temperature (15°C), 1: External Baro, 2: Airspeed

float32 rho				# air density

uint8 calibration_count     # Calibration changed counter. Monotonically increases whenever calibration changes.

```
