Navigation mode selection apparatus
First Claim
1. A navigation mode selection apparatus for utilization in a navigation system of the type having a plurality of navigation modes, each mode providing a position signal generated by a respective one of a plurality of navigation mode position determining procedures, comprising:
- error estimator means for providing mode error signals representative of position error estimates for each of said plurality of navigation modes; and
navigation mode selector means responsive to said mode error signals for selecting from said plurality of navigation modes one navigation mode having a mode error signal representative of a position error estimate which is less than position error estimates represented by mode error signals from other navigation modes of said plurality of navigation modes and for providing said mode error signal of said one navigation mode;
low pass position filter means having a predetermined time constant and coupled to receive said position signal for providing said position signal with a slow-in function, thereby eliminating abrupt position signal changes when switching between navigation modes;
low pass position error filter means having a time constant equal to said predetermined time constant and coupled to receive said mode error signals of said one navigation mode from said navigation mode selector means for providing a position error signal representative of estimated position error to said one navigation mode; and
validation means coupled to said low pass position filter means and said low pass position error filter means for validating input navigation data presented by said one navigation mode by comparing said position signal to a threshold set in accordance with said position error signal, whereby an unfavorable comparison of said position signal to said threshold causes said navigation mode selector means to select a navigation mode other than said one navigation mode.
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Accused Products
Abstract
An aircraft navigation system supporting a plurality of navigation modes. An error estimator for each navigation mode provides an estimated navmode error signal representative of an estimate of the error in the position signal generated by the associated navmode. A navigation mode selector enables the navmode having the smallest estimated navmode error signal that is consistent with procedure specified navaid criteria. The navmode computed position signal is processed through a low pass position filter. The estimated navmode error signal associated with the selected navmode is processed through a low pass position error filter having the same time constant as the low pass position filter to provide an estimated position error. The estimated position error is utilized in providing the INS and DEAD RECKONING navigation as well as to set a threshold for estimated navmode error signals sensor data validation.
38 Citations
5 Claims
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1. A navigation mode selection apparatus for utilization in a navigation system of the type having a plurality of navigation modes, each mode providing a position signal generated by a respective one of a plurality of navigation mode position determining procedures, comprising:
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error estimator means for providing mode error signals representative of position error estimates for each of said plurality of navigation modes; and navigation mode selector means responsive to said mode error signals for selecting from said plurality of navigation modes one navigation mode having a mode error signal representative of a position error estimate which is less than position error estimates represented by mode error signals from other navigation modes of said plurality of navigation modes and for providing said mode error signal of said one navigation mode; low pass position filter means having a predetermined time constant and coupled to receive said position signal for providing said position signal with a slow-in function, thereby eliminating abrupt position signal changes when switching between navigation modes; low pass position error filter means having a time constant equal to said predetermined time constant and coupled to receive said mode error signals of said one navigation mode from said navigation mode selector means for providing a position error signal representative of estimated position error to said one navigation mode; and validation means coupled to said low pass position filter means and said low pass position error filter means for validating input navigation data presented by said one navigation mode by comparing said position signal to a threshold set in accordance with said position error signal, whereby an unfavorable comparison of said position signal to said threshold causes said navigation mode selector means to select a navigation mode other than said one navigation mode. - View Dependent Claims (2, 3, 4, 5)
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Specification