LAND-BASED NAVIGATION USING ON-THE-FLY ELEVATION ASSESSMENTS
First Claim
1. A method for providing real-time navigation assistance on land-based vehicular roadways using on-the-fly elevation determinations, said method comprising the steps of:
- providing a digital road map having a representation of a road network corresponding to a plurality of roads in reality, each road in reality having a measurable elevation above sea level at any given geo-position there along;
providing a mobile navigation device interactive with the digital map, the navigation device capable of determining its instantaneous geo-position in the digital road network relative to the road in reality;
transporting the navigation device along a road in reality while simultaneously updating its corresponding geo-position in the digital road network;
conducting an on-the-fly search for local absolute atmospheric pressure readings (QNH) via wireless transmission;
selecting a reliable local absolute atmospheric pressure reading (QNH);
measuring the actual ambient atmospheric pressure;
calculating a current road elevation as a function of the measured actual and selected absolute (QNH) pressures; and
associating the calculated current road elevation with the corresponding instantaneous geo-position of the navigation device.
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Accused Products
Abstract
Real time navigation assistance is provided on multi-level roadways using on-the-fly elevation determinations obtained by measuring the ambient air pressure. Absolute air pressure measurements adjusted to sea level (QNH) are obtained by on-the-fly wireless searches. A navigation device (10) calculates its current elevation above sea level as a function of the measured ambient actual pressure and a selected local QNH reading. This elevation is correlated to a digital map so that the navigation device (10) can be accurately located relative to a multi-level roadway. Elevation readings along any road segment (14) can be transmitted to a map update center for the purpose of updating and improving digital map data.
18 Citations
15 Claims
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1. A method for providing real-time navigation assistance on land-based vehicular roadways using on-the-fly elevation determinations, said method comprising the steps of:
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providing a digital road map having a representation of a road network corresponding to a plurality of roads in reality, each road in reality having a measurable elevation above sea level at any given geo-position there along; providing a mobile navigation device interactive with the digital map, the navigation device capable of determining its instantaneous geo-position in the digital road network relative to the road in reality; transporting the navigation device along a road in reality while simultaneously updating its corresponding geo-position in the digital road network; conducting an on-the-fly search for local absolute atmospheric pressure readings (QNH) via wireless transmission; selecting a reliable local absolute atmospheric pressure reading (QNH); measuring the actual ambient atmospheric pressure; calculating a current road elevation as a function of the measured actual and selected absolute (QNH) pressures; and associating the calculated current road elevation with the corresponding instantaneous geo-position of the navigation device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15)
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14. A method for providing real-time navigation assistance on multi-level overlapping roadways using on-the-fly elevation determinations, said method comprising the steps of:
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providing a digital road map having a representation of a road network corresponding to a plurality of roads in reality, each road in reality having a fixed and measurable elevation above sea level at any given geo-position there along;
at least one road in reality overlying another road in reality but at an offset elevation;providing a mobile navigation device interactive with the digital map, the navigation device configured to determine its instantaneous geo-position in the digital road network relative to the road in reality based on data transmitted from a constellation of satellites; transporting the navigation device along a road in reality while simultaneously updating its corresponding geo-position in the digital road network; simultaneously with said transporting step, conducting an on-the-fly search for local absolute atmospheric pressure (QNH) readings via wireless transmission; selecting a reliable local absolute atmospheric pressure reading (QNH) relatively near in geo-position and time to the instantaneous geo-position of the navigation device; measuring the ambient actual atmospheric pressure; calculating a current elevation of the navigation device above sea level as a function of the measured ambient actual and selected absolute (QNH) pressures; associating the calculated current road elevation with the corresponding instantaneous geo-position of the navigation device; mapping the navigation device to a specific one of the two overlying roads in reality at least partially based on the calculated current elevation of the navigation device; providing navigation assistance based on the calculated current road elevation; updating the on-board digital map with the calculated elevation at the corresponding geo-position by saving the calculated elevation as an attribute; and transmitting the calculated elevation at the corresponding geo-position to a map update center.
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Specification