Minimum safe altitude monitoring, indication and warning system

A minimum safe altitude monitoring system for vehicles navigating over known terrain, said system comprising in combination with navigation computer means operable ongoingly to determine present position of the vehicle and to provide position coordinate signals related to present position, wherein said navigation computer means are further responsive to aircraft ground speed and ground track to provide position coordinate signals representing the predicted position of the vehicle within a predetermined travel interval from said present position,

• data storage means having recorded therein minimum safe altitude value data for each of respective predetermined sectional areas of a geographic territory over which the vehicle may navigate,
• data retrieval means utilizing said coordinate signals ongoingly to selectively retrieve from said data storage means minimum safe altitude values to produce an output therefrom related to present position minimum safe altitude, and a pilot warning device connected to receive said output,
• and means controlling initiation of operation of said warning device in response to a predetermined difference between present altitude of the vehicle and said output minimum safe altitude value.

A machine-implemented automatic method of directing the altitude travel of a vehicle to occur above minimum safe altitude along any ground track over known navigable territory, said method employing a programmable memory and comprising the steps of

• storing safe altitude data values for each of respective predetermined geographic areas of said territory within said programmable memory, each said minimum safe altitude data value for each of said geographic areas being based on terrain elevation features at least in and throughout the immediately adjoining geographic areas in any direction to thereby assume any possible ground track direction from any possible present position in each area, ongoingly deriving position coordinate signals representing present position of the vehicle in terms of the successive geographic areas over which the vehicle is currently progressing along a ground track, applying said signals to retrieve the respective recorded data values in successive order that relate to said geographic areas currently being traversed successively on said ground track, and applying said retrieved data values to produce a directing output response based on such respective data values.

A machine-implemented method for automatically deriving command signals for maintaining travel of a vehicle to occur above minimum safe altitude while said vehicle navigates along any ground track that extends over known navigable territory, said method employing a programmable memory and comprising the steps of

• storing minimum safe altitude data values for each of respective predetermined geographic areas of said territory within said programmable memory, each said minimum safe altitude data value for each of said geographic areas representing elevation terrain hazard features unique to each area, ongoingly deriving position coordinate signals representing present position of the vehicle in terms of the successive geographic areas over which the vehicle is currently progressing along a ground track, ongoingly deriving coordinate signals related to a predicted position of the vehicle within a predetermined imminent travel interval based on said present position, ground track and ground speed, and determining the maximum stored data value of the geographic areas extending between and including said present position and said predicted position to produce a directing output response indicative of the minimum safe altitude for said present position of said vehicle.