초록 ▼

An apparatus for use in an aircraft for determining and displaying a reading which is indicative of pressure density at any instant in time, comprises sensing means for determining both ambient air pressure and ambient air temperature at any instant in time, and outputting an electrical signal havin

An apparatus for use in an aircraft for determining and displaying a reading which is indicative of pressure density at any instant in time, comprises sensing means for determining both ambient air pressure and ambient air temperature at any instant in time, and outputting an electrical signal having a value which varies in accordance therewith. Calculating means are provided for combining those electrical signals and outputting a weighted signal for pressure density having a value based on an index value of zero for a pressure density at sea level when the ambient temperature is 59.degree. F. and the ambient pressure is 29.92 inches of mercury. A microprocessor computer means has random access memory and read only memory, and an output signal driver for outputting a signal indicative of pressure density at any instant in time to a display. The microprocessor includes a lookup and comparator means, and the read only memory contains a plurality of calculated values of pressure density over a range of barometric pressure values. The weighted signal from the calculating means is read by the lookup and comparator means, and compared with values of pressure density stored in the read only memory, so as to determine the value of pressure density at that instant in time, and to display that value. The apparatus will also provide a real time indication of chosen aircraft flying characteristics, depending on the parameters selected, from further lookup tables included in the read only memory.

대표청구항 ▼

1. An apparatus for use in an aircraft for determining and displaying a reading on a display, which reading is indicative of pressure density at any instant in time, wherein said apparatus comprises:sensing means for determining ambient air pressure of the location where an aircraft is situated at a

1. An apparatus for use in an aircraft for determining and displaying a reading on a display, which reading is indicative of pressure density at any instant in time, wherein said apparatus comprises:sensing means for determining ambient air pressure of the location where an aircraft is situated at any instant in time, and outputting an electrical signal having a value which varies in accordance with the ambient air pressure of the location where the aircraft is located, at any instant in time; sensing means for determining ambient air temperature of the location where an aircraft is situated at any instant in time, and outputting an electrical signal having a value which varies in accordance with the ambient air temperature of the location where the aircraft is located, at any instant in time; calculating means for combining the electrical signals from said sensing means for ambient air pressure and ambient air temperature, and outputting a weighted signal for pressure density having a value based on an index value of zero for a pressure density at sea level when the ambient temperature is 59.degree. F. and the ambient pressure is 29.92 inches of mercury; microprocessor computer means having both random access memory and read only memory, and having output signal driver means for outputting a signal indicative of pressure density at any instant in time; and a display means for displaying a value of pressure density in respect of the location of an aircraft at any instant in time, based on the value of the signal received from said output signal driver means; wherein said microprocessor computer means includes a lookup and comparator means, and said read only memory contains a plurality of calculated values of pressure density over a range of barometric pressure values chosen from the limits of from 28.5 inches of mercury to 31.5 inches of mercury, and a range of temperature values chosen from the limits of from -40.degree. F. to +130.degree. F.; whereby the weighted signal from said calculating means may be read by said lookup and comparator means, and compared with values of pressure density stored in said read only memory, so as to determine the value of pressure density at that instant in time as represented by said weighted signal; and wherein the determined value of pressure density at that instant in time is fed to said output signal driver means so as cause said display means to display said determined value of pressure density in respect of the location of the aircraft at that instant in time.