Method and apparatus for achieving sole means navigation from global navigation satelite systems

A global positioning system (GPS) navigation apparatus providing a sole source of navigation for an aircraft, the apparatus comprising:

• GPS receiver means for providing GPS measurement data;
• inertial sensor means for providing inertial measurement data which during time periods is independent of the GPS measurement data;
• navigation solution determining means for generating navigation data as a function of both the GPS measurement data and the inertial measurement data;
• and
• augmentation means for optimizing an accuracy of the inertial measurement data.

A method of generating navigation data using a global positioning system (GPS) navigation apparatus adapted for use on an aircraft, the method comprising:

• generating GPS measurement data using a GPS receiver;
• providing augmentation data independently of the GPS measurement data;
• generating inertial measurement data, which during time periods is independent of the GPS measurement data using an inertial sensor;
• and
• generating the navigation data as a function of both the GPS measurement data, the inertial measurement data, and the augmentation data.

A global positioning system (GPS) navigation apparatus adapted for use on an aircraft, the apparatus comprising:

• a GPS receiver adapted to provide GPS measurement data;
• an inertial sensor adapted to provide inertial measurement data which is independent of the GPS measurement data;
• navigation solution determining means coupled to each of the GPS receiver and the inertial sensor for determining a navigation solution as a function of both the GPS measurement data and the inertial measurement data and wherein the navigation solution determining means further comprises:
• a first Kalman filter coupled to the GPS receiver and adapted to filter the GPS measurement data to provide first filtered GPS data;
• a second Kalman filter coupled to the inertial sensor and adapted to filter the inertial measurement data to provide first filtered inertial data;
• a third Kalman filter coupled to the inertial sensor and adapted to filter the inertial measurement data to provide second filtered inertial data;
• and
• a processor adapted to implement receiver autonomous integrity monitoring algorithms using the first filtered GPS data and the first filtered inertial data to provide the navigation solution and
• wherein the navigation solution determining means is adapted to alternate between utilizing the first filtered inertial data and utilizing the second filtered inertial data in determining the navigation solution and
• wherein the navigation solution determining means is adapted to alternate between utilizing the first filtered inertial data and the second filtered inertial data during consecutive windows of time, each of the consecutive windows of time starting at a time of receipt of the integrity monitoring signals by the integrity monitoring receiver;
• an augmentation system coupled to the navigation solution determining means wherein the augmentation system is adapted to reduce errors in the inertial measurement data used by the navigation solution determining means in a manner which is independent of the GPS measurement data provided by the GPS receiver;
• and
• an integrity monitoring receiver adapted to receive integrity monitoring signals from a ground based satellite integrity monitoring station, the integrity monitoring signals being indicative of whether a satellite failure has been detected by the satellite integrity monitoring station.

A method of generating navigation data using a global positioning system (GPS) navigation apparatus adapted for use on an aircraft, the method comprising:

• generating GPS measurement data using a GPS receiver;
• providing augmentation data independently of the GPS measurement data;
• generating inertial measurement data, which during time periods is independent of the GPS measurement data using an inertial sensor;
• applying Kalman filter functions to the GPS measurement data to provide first filtered GPS data;
• applying Kalman filter functions to the inertial measurement data to provide first filtered inertial data;
• applying Kalman filter functions to the inertial measurement data to provide second filtered inertial data;
• implementing receiver autonomous integrity monitoring (RAIM) algorithms using the first filtered GPS data and the first filtered inertial data to substantiate the GPS measurement data, the augmentation data and the inertial measurement;
• receiving integrity monitoring signals from a ground based satellite integrity monitoring station, the integrity monitoring signals being indicative of whether a satellite failure has been detected by the satellite integrity monitoring station;
• alternating between implementing the RAIM algorithms using the first filtered inertial data and the second filtered inertial data to determine the navigation solution wherein alternating further comprises alternating between utilizing the first filtered inertial data and the second filtered inertial data during consecutive windows of time, with each of the consecutive windows of time starting at a time corresponding to a time of receipt of the integrity monitoring signals;
• and
• generating navigation data as a function of both the GPS measurement data, the inertial measurement data, and the augmentation data.