System for compressing aircraft flight data utilizing a multilevel time format
First Claim
1. In an aircraft flight data recorder system of the type wherein a plurality of input data signals that represent the status of corresponding aircraft parameters are periodically processed to provide a series of data frames with each data frame representing the status of selected ones of said aircraft parameters at particular points in time and with each data frame providing aircraft parameter status and associated time information that is stored in a memory device of the flight data recorder system for later retrieval therefrom, the improvement comprising:
- (a) means for periodically producing within each data frame at least one reference time signal representative of elapsed time from a predetermined initial point in time;
(b) means for sequentially determining, in accordance with a predetermined program, whether a signal representative of an input datum signal of said plurality of input data signals is to be included in a data frame, said means for sequentially determining including;
(i) means for producing for each input datum signal to be represented in said data frames a label signal representative of the aircraft parameter corresponding to the input datum signal,(ii) means for producing for each said datum signal to be represented in said data frame, a time tag signal that is referenced to said reference time signal and is representative of a time interval within which the datum signal was produced, and(iii) means for producing for each said input datum signal to be represented in said data frame, a datum value signal representative of the input datum signal.
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Accused Products
Abstract
A data processing system for use in a solid state flight data recorder wherein a plurality of aircraft parameter signals are processed and stored in electronic memory for later retrieval. The processor identifies those aircraft parameter data signals to be stored and for each such datum signal produces a signal triplet comprised of a parameter label signal, a time tag signal representative of the time interval from a reference time within which the data signal was produced, and the datum signal. A frame of the data bit stream produced by the data processor for storage in the memory includes an initial reference time signal followed at fixed intervals by time tick signals. Each signal triplet is positioned in the data bit stream following that initial reference time signal or time tick signal to which its time tag signal is referenced. By so tiering the data time formatting a substantial compression of data is realized thereby reducing memory size requirements.
44 Citations
36 Claims
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1. In an aircraft flight data recorder system of the type wherein a plurality of input data signals that represent the status of corresponding aircraft parameters are periodically processed to provide a series of data frames with each data frame representing the status of selected ones of said aircraft parameters at particular points in time and with each data frame providing aircraft parameter status and associated time information that is stored in a memory device of the flight data recorder system for later retrieval therefrom, the improvement comprising:
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(a) means for periodically producing within each data frame at least one reference time signal representative of elapsed time from a predetermined initial point in time; (b) means for sequentially determining, in accordance with a predetermined program, whether a signal representative of an input datum signal of said plurality of input data signals is to be included in a data frame, said means for sequentially determining including; (i) means for producing for each input datum signal to be represented in said data frames a label signal representative of the aircraft parameter corresponding to the input datum signal, (ii) means for producing for each said datum signal to be represented in said data frame, a time tag signal that is referenced to said reference time signal and is representative of a time interval within which the datum signal was produced, and (iii) means for producing for each said input datum signal to be represented in said data frame, a datum value signal representative of the input datum signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In a flight data recorder that is connectable for receiving a plurality of data signals that are supplied by one or more systems of an aircraft with each datum signal of said plurality of data signals representing the status of an aircraft parameter at a point in time, apparatus comprising:
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memory means for predeterminedly storing signals loaded therein, and data processing means including; (a) means for periodically producing a reference time signal representative of elapsed time from a predetermined initial time period, (b) means for sequentially determining, in accordance with a predetermined program, whether each datum signal is to be stored in said memory means and, in response to determining that a datum signal is to be stored, producing a triplet signal, said triplet signal comprising; (i) a label signal representative of the aircraft parameter corresponding to said datum signal, (ii) a time tag signal representative of a time interval from said reference time within which said datum signal was produced, and (iii) a datum signal value representative of said datum signal, and (c) means for predeterminedly combining said data processing means produced signals into a data bit stream suitable for loading into said memory means. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. Apparatus for recovering flight data recorder stored data which has been compressed prior to loading into the memory of said flight data recorder, the compression format for each frame of said data including a reference time signal representative of elapsed time from a predetermined initial time period followed by triplet signals, each triplet signal including a label signal representative of the parameter being stored, a time tag signal representative of a time interval from said reference time in which the datum value for said parameter was recorded, and a signal representative of the corresponding datum signal for the parameter being stored, the apparatus comprising:
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(a) means for identifying each frame of data stored in said memory, and (b) means for processing the reference time signal and the time tag signal associated with each triplet signal in each frame of data and producing, for each triplet signal, a data output information signal representative of the parameter, its value and the time at which its value was recorded. - View Dependent Claims (23, 24, 25, 26)
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27. In a method of recording digital signal information representative of a plurality of periodically sampled aircraft operating parameters wherein said digital signal information is presented in a series of repeating data frames, the steps of:
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(a) generating within each data frame a reference time signal representative of elapsed time between a predetermined initial point in time and the generation of said reference signal; (b) sequentially testing said plurality of periodically sampled aircraft operating parameters to determine whether the tested periodically sampled aircraft operating parameter will be represented in said data frame; (c) producing for each one of said periodically sampled aircraft operating parameters to be represented in said data frame a label signal representative of the aircraft operating parameter; (d) producing for each said one of said plurality of periodically sampled aircraft operating parameters to be included in said data frame a datum value signal representative of the current value of said periodically sampled aircraft operating parameter that is being represented in said data frame; and
,(e) producing for each one of said plurality of said periodically sampled aircraft operating parameters being included in said data frame a time tag signal representative of the number of time intervals of a predetermined length that have elapsed between generation of said time reference signal and production of said datum value signal. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification