System and Method for Determining a Velocity of a Rotorcraft

A flight control system for a rotorcraft comprising:

• a flight control computer (FCC) operable to control one or more flight control devices of the rotorcraft;
• and
• an attitude and heading reference system (AHRS) communicatively connected to the FCC, the AHRS comprising:
• a processor and a non-transitory computer readable storage medium with an executable program stored thereon, the executable program including instructions for:
• receiving groundspeed data from a GPS;
• receiving acceleration data;
• processing the groundspeed data and the acceleration data using a complementary filter to generate velocity data;
• and
• transmitting the velocity data to the FCC, wherein the FCC is operable to control the one or more flight control devices of the rotorcraft according to the velocity data.

A rotorcraft comprising:

• a flight control computer (FCC);
• a GPS receiver configured to detect a first carrier signal and calculate a groundspeed based on the first carrier signal, the GPS receiver coupled to the FCC;
• an attitude and heading reference system (AHRS) configured to determine an acceleration of the rotorcraft, the AHRS coupled to the GPS receiver system and to the FCC, wherein the AHRS is operable to receive an indication of the groundspeed from the GPS receiver and to calculate a velocity of the rotorcraft based on the indication of the groundspeed and the acceleration;
• and
• one or more flight control devices coupled to the FCC and operable to control a flight parameter of the rotorcraft in response to a flight control device control signal received from the FCC;
• wherein the FCC is operable to receive an indication of the velocity from the AHRS, to generate the flight control device control signal according to the indication of velocity, and to send the flight control device control signal to the one or more flight control devices.