Navigation instrument for roadway vehicles
First Claim
1. A navigation instrument for roadway vehicles comprising:
- means for generating an actual distance signal representing a distance travelled from a starting point of a journey;
means for generating an elapsed time signal representing the length of time elapsed from said starting point;
at least two of first, second and third means, said first means including means for arithmetically dividing said actual distance signal by said elapsed time signal to generate an average speed signal representing the average speed of said vehicle over said distance travelled from said starting point;
said second means including means for generating a constant speed reference signal representing an estimated average vehicle speed, means for arithmetcially multiplying said constant speed reference signal with said elapsed time signal to generate a distance reference signal representing an estimated distance from said starting point, and means for arithmetically subtracting said actual distance signal from said distance reference signal to generate a distance deviation signal representing the deviation of said distance travelled from said starting point from said estimated distance; and
said third means including means for generating a time deviation signal representing the deviation of said length of time elapsed from said starting point from an estimated length of time from said starting point; and
means for visually indicating at least two of said average speed signal, said distance deviation signal and said time deviation signal.
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Abstract
A navigation instrument for roadway vehicles comprises a first counter for counting pulses each occurring in response to the vehicle moving a predetermined distance to detect the distance travelled from the starting point of a trip, a second counter for counting clock pulses to detect the time elapsed from the start of the vehicle. A microcomputer or digital circuitry is provided to compute on the data received from the first and second counters to derive an output data representative of the average speed of the vehicle over the distance so far travelled and to compare the computed average speed with a desired speed to detect the deviation of the actual average speed from the reference. A comparator is provided to detect when this deviation exceeds a predetermined value to generate a warning signal to alert the vehicle driver to correct the vehicle speed.
25 Citations
7 Claims
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1. A navigation instrument for roadway vehicles comprising:
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means for generating an actual distance signal representing a distance travelled from a starting point of a journey; means for generating an elapsed time signal representing the length of time elapsed from said starting point; at least two of first, second and third means, said first means including means for arithmetically dividing said actual distance signal by said elapsed time signal to generate an average speed signal representing the average speed of said vehicle over said distance travelled from said starting point;
said second means including means for generating a constant speed reference signal representing an estimated average vehicle speed, means for arithmetcially multiplying said constant speed reference signal with said elapsed time signal to generate a distance reference signal representing an estimated distance from said starting point, and means for arithmetically subtracting said actual distance signal from said distance reference signal to generate a distance deviation signal representing the deviation of said distance travelled from said starting point from said estimated distance; and
said third means including means for generating a time deviation signal representing the deviation of said length of time elapsed from said starting point from an estimated length of time from said starting point; andmeans for visually indicating at least two of said average speed signal, said distance deviation signal and said time deviation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification