Portable device for determining horizontal and vertical positions and method for operating the same

• US 20040054470A1
• Filed: 09/17/2002
• Published: 03/18/2004
• Est. Priority Date: 03/22/2000
• Status: Active Grant

• Current Assignee: The Swatch Group Research And Development Ltd (The Swatch Group AG)
• Original Assignee: Asulab SA (The Swatch Group AG)
• Inventors: Farine, Pierre-Andre, Etienne, Jean-Daniel
• Granted Patent: US 6,882,308 B2
• Time in Patent Office: Days
• US Class Current: 701/213
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks

Abstract

The portable device (10) is used for determining horizontal and vertical positions. It includes a pressure sensor altimeter (15) calibrated to a predetermined initial altitude, a GPS signal receiver (12) arranged to receive, via an antenna (11), signals originating from several satellites (20) in order to calculate position data of the device, a processing unit (14) receiving the position data from the receiver (12) and an altitude value from the altimeter (15), and display means (16) for the horizontal and vertical positions of the device processed and provided by the processing unit. The processing unit sends the GPS receiver a signal corresponding to the altitude value of the calibrated altimeter to enable the receiver to determine, using the altitude value, the position data of the device. A memory (13) including cartographic data and associated with the GPS receiver (12) can provide the precise data to the processing unit (14) in particular for calibrating the altimeter.

Claims

1. Portable device for determining horizontal and vertical positions incorporated, in particular, in a timepiece or a portable telephone, said device including a pressure sensor altimeter (15) calibrated to a predetermined initial altitude, a GPS signal receiver (12) arranged to receive signals originating from several satellites (20) in order to calculate position data of the device (10), a processing unit (14) receiving the position data from the receiver (12) and an altitude value from the altimeter (15) based on pressure measurements of the pressure sensor with respect to the predetermined altitude, and display means (16) for the horizontal and vertical positions of the device processed and provided by the processing unit, said device being powered by a low power consuming battery or accumulator, characterised in that the processing unit (14) sends the GPS receiver (12) a signal (Z=h) corresponding to the altitude value of the calibrated altimeter (15) to enable the calculating time of a low power consuming microcontroller (24) of the receiver (12) to be reduced in order to determine, using the altitude value, position data of the device.

2. Device according to claim 1, characterised in that storage means (13) including cartographic data for a region are associated with the GPS receiver (12) to enable it to provide the processing unit (14) with precise position data if the position calculated by said receiver corresponds to a geographical point stored in said storage means.

3. Device according to claim 2, characterised in that the storage means (13) are an EEPROM type non-volatile memory into which the cartographic data is electrically introduced and deleted.

4. Device according to claims 2 or 3, characterised in that the storage means (13) including the cartographic data for a region are incorporated in a module which can be removed from said device in order to be able to change said module as a function of a determined geographical region of use of said device.

5. Device according to claim 1, characterised in that the receiver (12) and the processing unit (14) each include a low power consuming microcontroller (24, 42), in particular an 8-bit microcontroller.

6. Device according to claim 1, characterised in that the operations in the receiver are clocked at clock frequencies higher than one MHz, whereas the operations in the processing unit are clocked at clock frequencies lower than 100 kHz.

7. Device according to claims 1 or 2, characterised in that the receiver (12), the altimeter (15), the processing unit (14) and the storage means (13) are fixed onto the same support.

8. Device according to any of the preceding claims, characterised in that it is incorporated in a timepiece, particularly a wristwatch, or in a portable telephone.

9. Device according to claim 1, characterised in that the receiver (12) is arranged to send to the processing unit (14), in addition to the position data (X, Y, Z), quality parameters (DOPG) extracted from the radio waves transmitted by the satellites (20) so that the processing unit (14) can determine the precision of the position data received from the receiver.

10. Method for determining horizontal and vertical positions for operating the device according to any of the preceding claims, characterised in that it includes the steps of:

calibrating the pressure sensor altimeter (15) to a predetermined initial altitude using data processed and provided by the processing unit (14),

transmitting an altitude value of the calibrated altimeter (15) to the processing unit (14),

sending a signal (Z=h) corresponding to the altitude value of the calibrated altimeter (15) from the processing unit (14) to the GPS receiver (12) to enable the calculating time of a low power consuming microcontroller (24) of the receiver to be reduced in order to determine, using the altitude value, the position data as a function of the radio waves received from several satellites (20), and

transmitting the position data calculated by the receiver (12) to the processing unit (14) so that they are processed and displayed on display means (16).

11. Method according to claim 10, characterised in that the data for calibrating the altimeter (15) to a predetermined precise altitude is extracted from memory means (13) including cartographic data for a region and associated with the GPS receiver (12) for transmission to the processing unit (14).

12. Method according to claim 10, characterised in that in addition to the position data, the receiver (12) transmits quality parameters (DOPG) extracted from the radio waves received from the satellites (20) so that the processing unit (14) can determine the precision of the position data received from the receiver.

13. Method according to claim 12, characterised in that, in addition to the altitude value, the altimeter (15) transmits to the processing unit (14) a quality factor (QUAL) of said altitude value, and in that a comparison between the quality parameters (DOPG) of the receiver and the quality factor (QUAL) of the altimeter is carried out in the unit in order to determine the precise horizontal and vertical positions to be displayed.

14. Method according to claim 13, characterised in that the altimeter (15) is again calibrated to a predetermined altitude if the result of the comparison shows that the quality parameters (DOPG) originating from the receiver are better than the quality factor (QUAL) originating from the altimeter.

15. Method according to claim 10, characterised in that at the same place whose altitude has been stored, the pressure variations of the altimeter (15) sensor converted into altitude variations are used to determine, in the processing unit (14), meteorological conditions to be displayed, the altimeter being subsequently calibrated to the stored altitude.

16. Use of the device according to claim 1 for evaluating meteorological conditions, characterised in that the pressure sensor altimeter (15) calibrated to a predetermined initial altitude is arranged to provide, at an equivalent altitude to an altitude stored in a preceding period of time, pressure variations converted into altitude variations transmitted to the processing unit (14) so that it determines meteorological conditions to be displayed.