초록 ▼

In a system for estimating the launch point of a missile, Doppler shifted signals reflected from the missile as it travels from its launch point are used in a Kalman filter to estimate the missile position, velocity and acceleration, in earth centered fixed coordinates. The coordinate system is rota

In a system for estimating the launch point of a missile, Doppler shifted signals reflected from the missile as it travels from its launch point are used in a Kalman filter to estimate the missile position, velocity and acceleration, in earth centered fixed coordinates. The coordinate system is rotated to a rotated earth fixed (REF) coordinate system in which the X-axis passes through the estimated missile launch point and the Z-axis is made parallel to the missile azimuth as represented by the missile velocity determined by the Kalman filter. The error in the downrange component of the missile launch point is then reduced to a minimum in the REF coordinate system using a square root information filter. The coordinate system is then rotated to a second rotated earth fixed coordinate system in which the X-axis passes through the updated launch point position and the Z-axis is positioned at 45 degrees from the missile azimuth. The Z-axis component and the Y-axis component of the error in the launch point is then reduced to a minimum in the new REF coordinate system using a square root information filter.

대표청구항 ▼

1. A method of estimating the launch point of a missile, comprising illuminating said missile with radar signals as said missile is launched from said launch point, receiving Doppler shifted signals reflected from said missile, estimating the velocity of said missile from the Doppler shifted signals

1. A method of estimating the launch point of a missile, comprising illuminating said missile with radar signals as said missile is launched from said launch point, receiving Doppler shifted signals reflected from said missile, estimating the velocity of said missile from the Doppler shifted signals reflected from said missile, establishing a rotated earth fixed coordinate system having an X-axis passing through an initial estimate of the launch point of said missile and having a Z-axis parallel to the azimuth of said missile as indicated by the estimated missile velocity and estimating launch point, in said rotated earth fixed coordinate system in response to the reflected Doppler shifted signals.