IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0833318
(2001-04-12)
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발명자
/ 주소 |
- Burgett, Scott
- Olivier, Tracy
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출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
18 인용 특허 :
24 |
초록
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A portable, handheld electronic navigation device includes an altimeter and a GPS unit. An internal memory stores cartographic data, for displaying the cartographic data on a display of the navigation device. Accordingly, the device is capable of displaying cartographic data surrounding a location o
A portable, handheld electronic navigation device includes an altimeter and a GPS unit. An internal memory stores cartographic data, for displaying the cartographic data on a display of the navigation device. Accordingly, the device is capable of displaying cartographic data surrounding a location of the unit as determined by GPS and altitude information as determined by the barometric altimeter and GPS. The device provides an enhancement of the calibration and hence the accuracy of barometric altimeter measurements with the aid of derived altitudes from a GPS. The device is able to determine the need for calibration and perform the subsequent computations necessary to facilitate the calibration. Furthermore, the device is able to determine a correction quantity that should be applied to barometric altitude readings, thereby allowing the device to be calibrated while in motion. Both of these features ultimately result in a more accurate determination of altitude. In accordance with an aspect of the invention, the altimeter of the navigation device may be calibrated with altitude information entered by a user, with altitude information obtained from the cartographic, with altitude information derived from GPS or with any combinations thereof.
대표청구항
▼
A portable, handheld electronic navigation device includes an altimeter and a GPS unit. An internal memory stores cartographic data, for displaying the cartographic data on a display of the navigation device. Accordingly, the device is capable of displaying cartographic data surrounding a location o
A portable, handheld electronic navigation device includes an altimeter and a GPS unit. An internal memory stores cartographic data, for displaying the cartographic data on a display of the navigation device. Accordingly, the device is capable of displaying cartographic data surrounding a location of the unit as determined by GPS and altitude information as determined by the barometric altimeter and GPS. The device provides an enhancement of the calibration and hence the accuracy of barometric altimeter measurements with the aid of derived altitudes from a GPS. The device is able to determine the need for calibration and perform the subsequent computations necessary to facilitate the calibration. Furthermore, the device is able to determine a correction quantity that should be applied to barometric altitude readings, thereby allowing the device to be calibrated while in motion. Both of these features ultimately result in a more accurate determination of altitude. In accordance with an aspect of the invention, the altimeter of the navigation device may be calibrated with altitude information entered by a user, with altitude information obtained from the cartographic, with altitude information derived from GPS or with any combinations thereof. ransfer function over the partial clock interval based on the up-sampling value and the data to produce a first weighted area; determining a plurality of weighted areas under the predetermined filter transfer function based on the up-sampling value and the data, wherein each of the plurality of weighted areas corresponds to an interval of the clock; determining a final partial clock interval based on the partial clock interval and the output interval; determining a final weighted area under the predetermined filter transfer function over the final partial clock interval based on the up-sampling value and the data; and summing the first weighted area, the plurality of weighted areas, and the final weighted area to produce the moving sum. 3. The method of claim 1, wherein the predetermined filter transfer function is a second order function, wherein the computing the moving sum further comprises: calculating a current weighted triangle area based on a current interval of a clock operating at the clock rate, the data, and an equation of where n corresponds to the up-sampling value; determining current interval area based on a difference between the current weighted triangle area and a previous weighted triangle area; and accumulating the current interval area to produce the moving sum. 4. The method of claim 3, wherein the calculating the current weighted triangle area further comprises: determining a region of the predetermined filter transfer function based on a relationship between the down-sampling value and the current interval; and calculating the current weighted triangle area based on the region. 5. The method of claim 1, wherein the computing the moving sum further comprises: up-sampling the data based on the up-sampling value to produce up-sampled data; filtering the up-sampled data based on the predetermined filter transfer function to produce filtered data; and down-sampling the filtered data based on the down-sampling value to produce the digital output. 6. The method of claim 1 further comprises: computing an overlapping moving sum of second data of the stream of digital data based on the up-sampling value, the clock rate of the stream of digital data, and the predetermined filter transfer function; and producing a second digital output value from the moving sum based on the down-sampling value, wherein the second digital output value is at the desired output rate. 7. A sample rate converter for use in an analog to digital converter, wherein the analog to digital converter includes an oversampling quantizer that produces a digital stream of data at an oversampling rate from an analog input voltage, the sample rate converter comprises: decimation filter calculation module operably coupled to produce at least one reference area value per clock interval of the oversampling rate based on an up-sampling value, a down-sampling value, and a predetermined filter transfer function, wherein the up-sampling value and the down-sampling value are related based on a sample rate conversion value; inversion module operably coupled to receive the at least one reference area value and produce therefrom at least one inverted area value; and multiplexor operably coupled to receive, as inputs, the at least one reference area value and the at least one inverted area value, wherein the multiplexor receives, as a control signal, the digital stream of data, wherein based on a current data sample, the multiplexor outputs the at least one reference area value or the at least one inverted area as at least one weighted area value for a current clock interval. 8. The sample rate converter of claim 7 further comprises: decimation summing module operably coupled to compute an even moving sum and an odd moving sum of data of the stream of digital data based on an accumulation of the at least one weighted area value for a plurality of clock intervals of the oversampling rate; and decimation output modul
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