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US 5,587,910 AGranted
Vehicle navigation system with non-overflow digital filter
AssigneeRockwell International Corporation
InventorJeffrey P. Woodard
Life of this patent
Estimating the term…
Abstract
A vehicle navigation system uses a one-multiplier Gray-Markel filter. The sign parameter of each stage of the filter is selected by an algorithm which limits the maximum signal passing through the filter, thereby preventing overflow.
Claims2
A vehicle navigational system, comprising:
- (a) a vehicle;
- (b) a sensor mounted on the vehicle and producing a navigation signal;
- (c) a one-multiplier Gray-Markel filter having an input connected to receive the navigational signal, and having at least one stage, each stage comprising:
- (1) a first summer connected to receive, at a plus input, a first input to the stage;
- (2) a multiplier connected to multiply an output of the first summer by a constant k;
- (3) a second summer connected to receive:
- (A) at a plus input, the first input to the stage;
- and
- (B) at a variable input, an output of the multiplier, the variable input being:
- (1) a minus input if k is greater than 0;
- and
- (2) a plus input if k is less than 0;
- wherein an output of the second summer is a first output of the stage;
- (4) a delay element connected to:
- (A) receive a second input to the stage;
- and
- (B) apply an output to a complement input of the first summer, the complement input being the negative of the variable input;
- and
- (5) a third summer connected to receive:
- (A) at a first plus input, the output of the multiplier;
- and
- (B) at a second plus input, the output of the delay element;
- and
- (d) a filtered navigation signal display driven by an output of the one-multiplier Gray-Markel filter.
21 more elements
A vehicle navigational method, comprising the steps of:
- (a) mounting a sensor on the vehicle;
- (b) producing a navigation signal from the sensor;
- (c) filtering the navigation signal in at least one series of steps each such step series comprising the steps of:
- (1) creating a first sum by adding together a first input to the step series and a second addend described below;
- (2) multiplying the first sum by a constant k to produce a product;
- (3) creating a second sum by adding together:
- (A) the first input to the step series;
- and
- (B) the product, the product first being multiplied by -1 if k is greater than 0;
- the second sum being a first output of the step series;
- (4) delaying a second input to the step series, the delayed second input being the second addend to the first sum, the delayed second input first being multiplied by -1 if k is less than 0;
- and
- (5) creating a third sum by adding together:
- (A) the product;
- and
- (B) the delayed second input, without sign adjustment;
- and
- (d) displaying a filtered navigation signal emerging from an output of one of the step series.
15 more elements
Dependencies are inferred from the claim text.