Device for measuring altitude and barometric pressure

• US 5,224,059 A
• Filed: 11/21/1991
• Issued: 06/29/1993
• Est. Priority Date: 06/07/1988
• Status: Expired due to Term

• Current Assignee: Citizen Holdings Co., Ltd.
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Umemoto, Toshio, Nitta, Tatsuo, Kihara, Hiroyuki
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): PIPALA, EDWARD J
• Application Number:
  US07/794,848
• Time in Patent Office: 586 Days
• Field of Search: 364/558, 364/433, 364/571.01, 364/571.03, 364/705.01, 73/179, 73/4 R, 73/384-387, 377/19, 368/10, 368/11, 368/14
• US Class Current: 73/384
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G04B 47/066 with a pressure sensor
• CPC Class Codes: G04G 21/02 Detectors of external physical values, e.g. temperature

Abstract

A device for measuring altitude and barometric pressure having a barometric pressure sensor, an amplifying circuit for amplifying the output signal from the pressure sensor, an analog to digital converter for converting the output signal from the amplifying circuit to a digital signal, and an altitude information generator for generating altitude information from the output signal of the analog to digital converter. A display displays the altitude information from the altitude information generator and the pressure information detected by the pressure sensor with pressure variation information and converts it into precise altitude information in accordance with temperature compensation data and altitude compensating data based upon regional and time information. The device may be used in climbing or the like with remarkable reliability.

Claims

1. An altitude and barometric pressure measuring device, comprising:

a barometric pressure sensor including an amplifier for outputting an amplified analog signal from said sensor corresponding to the sensed atmospheric pressure;

an analog to digital converter for converting the amplified analog signal to a digital output signal;

a barometric pressure information generating means for outputting, when operated, data corresponding to atmospheric pressure in accordance with said digital output signal of the converter;

an altitude information generating means for outputting when operated, data corresponding to the altitude of the device in accordance with said digital output signal of the converter;

mode designating means for selectively operating the barometric pressure information generating means in a pressure measuring mode for outputting the data corresponding to atmospheric pressure, or the altitude information generating means in an altitude measuring mode for outputting the data corresponding to the altitude of the device; and

display means responsive to the output data for displaying selectively information indicative of the operation of said barometric pressure information generating means or said altitude information generating means.

2. The device of claim 1 wherein the altitude information generating means comprises

compensating circuit means operative when activated to compensate the altitude data output to the display device;

and the mode designating means includes means for activating the compensation circuit means when in an altitude compensating mode.

3. The device of claim 2 wherein the mode designating means includes means for activating the compensating circuit means prior to outputting data from the altitude information generating means at times when the designation means is in the altitude measuring mode.

4. The device of claim 1 wherein the mode designating means includes means for operating the altitude information generating means repetitively in a continuous operating mode, and includes means for operating the altitude information generating means momentarily in a brief term operating mode, and means for selecting in the alternative the continuous operating mode and the brief term operating mode.

5. The device of claim 1 wherein the pressure measuring mode includes a waiting mode for operating the pressure information generating means to output data at predetermined intervals.

6. The device of claim 4 wherein the means for operating the altitude information generating means in the continuous operating mode includes a continuous measuring waiting mode, an altitude compensating mode, and an altitude measuring mode for measuring altitude in accordance with compensating data of the altitude compensating more, the altitude measuring mode being responsive to the compensating mode.

7. The device of claim 4 wherein the means for operating the altitude information generating means in the brief term operating mode includes a brief measuring waiting mode, an altitude compensating mode and an altitude measuring mode for measuring altitude in accordance with compensating data of the altitude compensating mode, the altitude measuring mode being responsive to the altitude compensating mode.

8. The device of claim 6 or 7 wherein the altitude compensating mode includes a preliminary measuring mode for inputting data for each operation of the brief measuring waiting mode.

9. The device of claim 1, wherein said altitude information generating means includes an altitude information generating circuit, an altitude compensating means for compensating information data output from said altitude information generating circuit, and means for outputting the compensated altitude information from the altitude compensating means prior to the output from said altitude information generating means.

10. The device of claim 1 further comprising altitude compensating means for compensating data output from the altitude information generating means in response to input data, and an external information input circuit operable by an external operating device for supplying the input data to the altitude compensating means.

11. The device of claim 1 further comprising temperature compensating means for inputting data relating to temperature to the altitude information generating means.

12. The device of claim 11, wherein said temperature compensating means includes an external information input circuit responsive to an external operating device for inputting the data to the altitude information generating means.

13. The device of claim 10 or 12, wherein said external information input circuit is responsive to information corresponding to at least one of information corresponding to latitude and information corresponding to altitude.

14. The device of claim 9, wherein the altitude compensating means includes an altitude compensating circuit responsive to external input information for the altitude information generating means.

15. The device of claim 11 wherein the temperature compensating means includes means for obtaining data relative to temperature at sea level for compensating the data from the altitude information generating means.

16. The device of claim 11 wherein the temperature compensating means includes a latitude information input circuit responsive to a manually operable device for outputting information relating to latitude, a calendar information generating circuit responsive to a time signal generating device for generating calendar information, a processing circuit for determining the temperature at sea level in accordance with the generated calendar information and the latitude output information, a temperature compensating circuit responsive to processed sea level temperature for generating a compensated temperature output;

and further comprises altitude compensating means including an altitude compensating circuit responsive to the compensated temperature output, and an altitude input circuit responsive to an external input of actual latitude for generating compensated altitude information.

17. The device of claim 1 further comprising a barometric pressure variation information generating circuit for generating output information indicating in the alternative an increment or a decrement of barometric pressure in accordance with corresponding successive barometric pressure data measurements of the barometric pressure information generating means.

18. The device of claim 17, further comprising a display means for indicating barometric pressure variation information with a mark indicative of the existence of a pressure variation, in response to the output of the pressure variation information generating circuit.

19. The device of claim 17 wherein the altitude information generating means includes

a calendar information circuit responsive to a time signal generation circuit for outputting calendar information;

a temperature memory circuit for storing a temperature coefficient in accordance with calendar information generated by the calendar information circuit;

a latitude memory circuit for storing latitude information input from an external operating device;

an altitude information generating circuit for calculating the altitude in accordance with atmospheric pressure data output from the analog to digital converter;

a temperature compensating circuit for compensating the data generated by the altitude information generating circuit in accordance with data from at least one of the temperature and latitude memory circuits; and

an altitude compensating circuit for compensating the altitude information output from the temperature compensating circuit.

20. The device of claim 17 wherein the altitude information generating means includes

a calendar information circuit responsive to a time signal generation circuit for outputting calendar information;

a temperature memory circuit for storing a temperature coefficient in accordance with the calendar information generated by the calendar information circuit;

a latitude memory circuit for storing latitude information input from an external operating device;

a processing circuit for determining the atmospheric temperature at sea level in accordance with the temperature memory circuit and the latitude memory circuit;

an altitude information generating circuit for calculating the altitude in accordance with atmospheric pressure data output from the analog to digital converter;

a temperature compensating circuit for compensating data generated by altitude information generating circuit in accordance with data from at least one of the temperature and latitude memory circuits; and

an altitude compensating circuit for compensating the altitude information output from the temperature compensating circuit.