An attitude sensing apparatus for determining the attitude of a mobile unit is provided that can reliably estimate an alignment angle between a GPS antenna coordinate system and an IMU coordinate system with good accuracy regardless of the magnitude of the alignment angle. Based on observation of the difference between a GPS angular velocity and an IMU angular velocity, an alignment angle estimating section estimates an alignment angle and sensor errors. An alignment angle adder and a sensor error adder cumulatively add and update the estimated alignment angle and sensor errors, respectively. The estimated alignment angle is fed back to an inertia data converter while the estimated sensor errors are fed back to an inertia data correcting section. The apparatus repeatedly performs estimation until the estimated alignment angle gradually approaches a true alignment angle by successively feeding back estimated values to a flow of alignment angle estimation process.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuing application of application Ser. No. 10/438,915, filed on May 16, 2003 now abandoned, the entire contents of which are hereby incorporated by reference and for which priority is claimed under 35 U.S.C. .sctn. 120; and this application claims priority of application Ser. No. 2002-141576 filed in Japan on May 16, 2002 under 35 U.S.C. .sctn. 119.
A vertical takeoff and landing aircraft according to the invention includes multiple thrust producing devices that produce thrusts applied in the substantially vertically upward direction; a target attitude setting portion that sets a target attitude used in attitude control of the aircraft; an inertia moment deriving portion that derives an inertia moment applied around a predetermined rotational axis of the aircraft; and a thrust adjustment portion that adjusts, during the attitude control of the aircraft, the thrusts to be produced by the respective thrust producing devices based on the target attitude set by the target attitude setting portion and the inertia moment during the attitude control, which is derived by the inertia moment deriving portion.
An apparatus for estimating attitude using an inertia measuring apparatus comprising: a Kalman filter 3 adapted to receive a quantity of state .omega.(t) from the inertia measuring apparatus 1, input the quantity of state into a predetermined system equation and a predetermined observation equation and execute time update processing and observation update processing with regard to the system equation and the observation equation; a processing section 4 adapted to generate an estimated value of a time differentiation of a modified Rodrigues parameter .alpha.(t) based upon an output of the Kalman filter; an integral processing section 5 adapted to generate an estimated value of the modified Rodrigues parameter based upon an output of the processing section; a system propagation matrix generating section 6 adapted to update an observation sensitivity matrix based upon an initial value being given beforehand and an output of the integral processing section and supply the updated output to the Kalman filter; a transformed matrix generating section 7 adapted to generate a coordinate transformation matrix R based upon an output of the integral processing section; and an attitude estimation section 8 adapted to carry out an attitude estimation based upon an output of the transformed matrix generating section, is disclosed.
A system and method for compensating for changes in relative antenna attitude in a single-receiver position detection system, such as a differential carrier phase GPS system, utilizes sensor input to detect changes in the relative attitude of at least two antennas or an antenna positioner, such as an motorized actuator or operator, that orients or re-orients the antennas to a predetermined orientation. The changes in the detected relative carrier phase due to the right hand circular polarized nature of the carrier signals are thus corrected. In this way, the high positional accuracy associated with kinematic GPS systems, for example, can be achieved even when the system's antennas are not constrained by a common rigid body, for example.
