空速传感器

Airspeed sensors are highly recommended for fixed-wing and VTOL frames. They are so important because the autopilot does not have other means to detect stall. 对于固定翼飞行来说，保证升力的是空速而不是地速。

Hardware Options

Recommended digital airspeed sensors include:

• Based on Pitot tube (opens new window)
  • MEAS Spec series (e.g. MS4525DO (opens new window), MS5525 (opens new window))
    • mRo I2C Airspeed Sensor JST-GH MS4525DO (opens new window) (mRo store)
    • Digital Differential Airspeed Sensor Kit (opens new window) (Drotek).
  • EagleTree Airspeed MicroSensor V3 (opens new window) (eagletreesystems)
  • Sensirion SDP3x Airspeed Sensor Kit (opens new window)
  • Holybro Digital Air Speed Sensor (opens new window)
• Based on Venturi effect (opens new window)
  • TFSLOT Venturi effect airspeed sensor.

All the above sensors are connected via the I2C bus/port.

注解

Additionally, the Avionics Anonymous Air Data Computer (opens new window) can be connected to the CAN bus to determine not only high-accuracy airspeed, but also true static pressure and air temperature via onboard barometer and an OAT probe.

配置

Enable Airspeed Sensors

Airspeed sensor drivers are not started automatically. Enable each type using its corresponding parameter:

• Sensirion SDP3X: SENS_EN_SDP3X
• TE MS4525: SENS_EN_MS4525DO
• TE MS5525: SENS_EN_MS5525DS
• Eagle Tree airspeed sensor: SENS_EN_ETSASPD

You should also check ASPD_PRIMARY is 1 (see next section - this is the default).

Multiple Airspeed Sensors

If you have multiple airspeed sensors then you can select which sensor is preferred as the primary source using ASPD_PRIMARY, where 1, 2 and 3 reflect the order in which the airspeed sensors were started:

• -1: Disabled (no airspeed information used).
• 0: Synthetic airspeed estimation (groundspeed minus windspeed)
• 1: First airspeed sensor started (default)
• 2: Second airspeed sensor started
• 3: Third airspeed sensor started

The airspeed selector validates the indicated sensor first and only falls back to other sensors if the indicated sensor fails airspeed checks (ASPD_DO_CHECKS is used to configure the checks).

The selected sensor is then used to supply data to the estimator (EKF2). The EKF fuses the airspeed data if it's above EKF2_ARSP_THR and has a low innovation compared to groundspeed minus windspeed.

Sensor-specific Configuration

Other than enabling the sensor, sensor-specific configuration is often not required. If it is needed, it should be covered in the appropriate sensor page (for example TFSLOT > Configuration).

The specific configuration for sensors that do not have a separate page is listed below:

• Sensirion SDP3X: CAL_AIR_CMODEL (provides overview of required settings), CAL_AIR_TUBED_MM, CAL_AIR_TUBELEN.

Calibration

Airspeed sensors should be calibrated by following the instructions: Basic Configuration > Airspeed.

开发人员信息

• Airspeed drivers (opens new window) (source code)