Accurate time standard for vehicle operation

• US 5,625,556 A
• Filed: 04/28/1995
• Issued: 04/29/1997
• Est. Priority Date: 04/28/1995
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Janky, James M., Schipper, John F.
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/430,495
• Time in Patent Office: 732 Days
• Field of Search: 364/424.01, 364/449, 364/569, 342/357, 342/457, 368/47
• US Class Current: 701/1
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G04G 7/00 Synchronisation radio-controlled time-pieces G04R

Abstract

Apparatus and method for providing timing control signals for operation of an engine and other devices on a vehicle and/or operation of telecommunications equipment and/or computer equipment on the vehicle. A Satellite Positioning System (SATPS) antenna and receiver/processor receive and process signals from three or more SATPS satellites and determine and issue SATPS-determined timing pulses and time signals that indicate the time associated with each timing pulse. The pulse-to-pulse time separation Δt_pp of these timing pulses is adjusted to provide a separation approximately equal to a selected pulse separation Δt_incr. Alternatively, a supplementary timing device provides a sequence of timing pulses with pulse-to-pulse spacing that is adjustable by varying an environmental parameter θ, such as temperature or electrical field, for this timing device. The supplementary timing device pulse-to-pulse separation is determined by the SATPS-determined time signals and the environmental parameter θ is varied so that Δt_pp becomes approximately equal to a selected value Δt_incr that can be used for timing signals on the vehicle. The supplementary timing device pulses can also be used where the SATPS-determined time signals and timing pulses are not available. The SATPS may be a Global Positioning System (GPS), a Global Orbiting Navigational Satellite System (GLONASS) or any other suitable satellite-based system.

Claims

1. Apparatus for providing timing signals for operation of a vehicle, the apparatus comprising:

a Satellite Positioning System (SATPS) signal antenna and SATPS signal receiver/processor, connected together and positioned on a vehicle, to receive and process SATPS signals from at least three SATPS satellites and to determine and issue a first sequence of timing pulse signals and a second sequence of pulse time signals, where each pulse time signal in the second sequence indicates the time at which a timing pulse signal in the first sequence is issued;

timing pulse modification means for receiving the first sequence of timing pulse signals and the second sequence of pulse time signals and for generating and issuing a third sequence of timing pulse signals, where any two consecutive timing pulse signals in the third sequence are spaced apart by a time interval Δ

t₃ that is approximately equal to a selected time difference Δ

t_incr ; and

timing pulse distribution means for receiving the third sequence of timing pulse signals and for delivering these signals to a timing-controlled instrument that is positioned on the vehicle, where the timing-controlled instrument is drawn from the class of such instruments consisting of;

an engine to provide motional power for the vehicle;

a telecommunications instrument to transmit a telecommunications signal from the vehicle to a telecommunications instrument that is spaced apart from the vehicle;

a telecommunications instrument to receive a telecommunications signal at the vehicle from a telecommunications instrument that is spaced apart from the vehicle;

a computer microprocessor that is positioned on and can be used on the vehicle;

a computer clock that provides timing signals for a computer that is positioned on the vehicle;

a visually perceptible or audibly perceptible clock that is positioned on the vehicle.

2. The apparatus of claim 1, further comprising supplementary clock means, connected to said SATPS receiver/processor and to said timing pulse distribution means, for generating and issuing a fourth sequence of timing pulses that are spaced apart in time by a selectable time interval Δ

t₄ that is approximately equal to said selected time difference Δ

t_incr,

where said timing pulse distribution means accepts and delivers the fourth sequence of timing pulse signals to at least one of said timing controlled instruments whenever said third sequence of timing pulse signals is unavailable.

3. The apparatus of claim 1, further comprising signal correction means for receiving differential corrections of SATPS signals that, when combined with said SATPS signals, provides at least one time fix that has an inaccuracy of at most about 3 nanoseconds.

4. The apparatus of claim 1, wherein said timing controlled instrument is a telecommunications instrument that generates and transmits radiowave signals from said vehicle to a radiowave receiver that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

5. The apparatus of claim 1, wherein said timing controlled instrument is a telecommunications instrument that receives radiowave signals at a radiowave receiver on said vehicle from a transmitter that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

6. The apparatus of claim 1, wherein said Satellite Positioning System is drawn from the class of satellite-based location and time determination systems consisting of Global Positioning Systems and Global Orbiting Navigational Satellite Systems.

7. Apparatus for providing timing signals for operation of a vehicle, the apparatus comprising:

a Satellite Positioning System (SATPS) signal antenna and SATPS signal receiver/processor, connected together and positioned on a vehicle, to receive and process SATPS signals from at least three SATPS satellites and to determine and issue a first sequence of time signals at which a time fix is made;

supplementary timing means, for generating and issuing a second sequence of timing pulses that are spaced apart in time by a selectable time interval Δ

t₂, for receiving the first sequence of time signals from the SATPS receiver/processor, for using the first sequence of signals to adjust the selectable time interval value Δ

t₂ so that this time interval value is approximately equal to a selected time difference Δ

t_incr,2 ; and

timing pulse distribution means for receiving the third sequence of timing pulse signals and for delivering these signals to a timing-controlled instrument that is positioned on the vehicle, where the timing-controlled instrument is drawn from the class of such instruments consisting of;

an engine to provide motional power for the vehicle;

a telecommunications instrument to transmit a telecommunications signal from the vehicle to a telecommunications instrument that is spaced apart from the vehicle;

a telecommunications instrument to receive a telecommunications signal at the vehicle from a telecommunications instrument that is spaced apart from the vehicle;

a computer microprocessor that is positioned on and can be used on the vehicle;

a computer clock that provides timing signals for a computer that is positioned on the vehicle;

a visually perceptible or audibly perceptible clock that is positioned on the vehicle.

8. The apparatus of claim 7, wherein said supplementary timing means comprises:

oscillator means for generating and issuing said second sequence of timing pulses that are spaced apart in time by said time interval value Δ

t₂, where said time interval value can be adjusted by varying a selected parameter θ

of the environment in which the oscillator means is immersed;

timing pulse comparison means, for receiving said first, second and third sequences of signals from said SATPS receiver/processor and the oscillator means, for determining and issuing a time interval difference Δ

t_diff =Δ

t₂ -Δ

t₃, where Δ

t₃ is a selected time interval value; and

pulse spacing control means, connected to the oscillator means, for receiving the time interval difference signal Δ

t_diff and, if the magnitude of this signal Δ

t_diff is non-zero, for adjusting the selected environmental parameter θ

of the oscillator means to decrease the magnitude of the signal Δ

t_diff.

9. The apparatus of claim 7, further comprising signal correction means for receiving differential corrections of SATPS signals that, when combined with said SATPS signals, provides at least one time fixes that has an inaccuracy of at most about 3 nanoseconds.

10. The apparatus of claim 7, wherein said timing controlled instrument is a telecommunications instrument that generates and transmits radiowave signals from said vehicle to a radiowave receiver that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

11. The apparatus of claim 7, wherein said timing controlled instrument is a telecommunications instrument that receives radiowave signals at a radiowave receiver on said vehicle from a transmitter that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

12. The apparatus of claim 7, wherein said Satellite Positioning System is drawn from the class of satellite-based location and time determination systems consisting of Global Positioning Systems and Global Orbiting Navigational Satellite Systems.

13. A method for providing timing signals for operation of a vehicle, the method comprising the steps of:

providing a Satellite Positioning System (SATPS) signal antenna and SATPS signal receiver/processor, connected together and positioned on a vehicle, to receive and process SATPS signals from at least three SATPS satellites and to determine and issue a first sequence of timing pulse signals and a second sequence of pulse time signals, where each pulse time signal in the second sequence indicates the time at which a timing pulse signal in the first sequence is issued;

receiving the first sequence of timing pulse signals and the second sequence of pulse time signals, and generating and issuing a third sequence of timing pulse signals, where any two consecutive timing pulse signals in the third sequence are spaced apart by a time interval Δ

t₃ that is approximately equal to a selected time difference Δ

t_incr ; and

delivering this third sequence to a timing-controlled instrument that is positioned on the vehicle, where the timing-controlled instrument is drawn from the class of such instruments consisting of;

an engine to provide motional power for the vehicle;

a telecommunications instrument to transmit a telecommunications signal from the vehicle to a telecommunications instrument that is spaced apart from the vehicle;

a telecommunications instrument to receive a telecommunications signal at the vehicle from a telecommunications instrument that is spaced apart from the vehicle;

a computer microprocessor that is positioned on and can be used on the vehicle;

a computer clock that provides timing signals for a computer that is positioned on the vehicle;

a visually perceptible or audibly perceptible clock that is positioned on the vehicle.

14. The method of claim 13, further comprising the step of providing a supplementary clock means, connected to said SATPS receiver/processor and to said timing pulse distribution means, for generating and issuing a fourth sequence of timing pulses that are spaced apart in time by a selectable time interval Δ

t₄ that is approximately equal to said selected time difference Δ

t_incr,

where said timing pulse distribution means accepts and delivers the fourth sequence of timing pulse signals to at least one of said timing controlled instruments whenever said third sequence of timing pulse signals is unavailable.

15. The method of claim 13, further comprising the step of providing differential corrections of SATPS signals that, when combined with said SATPS signals, provides at least one time fix that has an inaccuracy of at most about 3 nanoseconds.

16. The method of claim 13, further comprising the step of choosing said timing controlled instrument to be a telecommunications instrument that generates and transmits radiowave signals from said vehicle to a radiowave receiver that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

17. The method of claim 13, further comprising the step of choosing said timing controlled instrument to be a telecommunications instrument that receives radiowave signals at a radiowave receiver on said vehicle from a transmitter that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

18. The method of claim 13, further comprising the step of choosing said Satellite Positioning System from the class of satellite-based location and time determination systems consisting of Global Positioning Systems and Global Orbiting Navigational Satellite Systems.

19. A method for providing timing signals for operation of a vehicle, the method comprising the steps of:

(1) providing a Satellite Positioning System (SATPS) signal antenna and SATPS signal receiver/processor, connected together and positioned on a vehicle, to receive and process SATPS signals from at least three SATPS satellites and to determine and issue a first sequence of timing pulse signals and a second sequence of pulse time signals, where each pulse time signal in the second sequence indicates the time at which a timing pulse signal in the first sequence is issued;

(2) generating and issuing a second sequence of timing pulses that are spaced apart in time by a selectable time interval Δ

t₂ ;

(3) receiving the first sequence of time signals from the SATPS receiver/processor, and using the first sequence of signals to adjust the selectable time interval value Δ

t₂ so that this time interval value is approximately equal to a selected time difference Δ

t_incr,2 ; and

(4) delivering this third sequence to a timing-controlled instrument that is positioned on the vehicle, where the timing-controlled instrument is drawn from the class of such instruments consisting of;

an engine to provide motional power for the vehicle;

a telecommunications instrument to transmit a telecommunications signal from the vehicle to a telecommunications instrument that is spaced apart from the vehicle;

a telecommunications instrument to receive a telecommunications signal at the vehicle from a telecommunications instrument that is spaced apart from the vehicle;

a computer microprocessor that is positioned on and can be used on the vehicle;

a computer clock that provides timing signals for a computer that is positioned on the vehicle;

a visually perceptible or audibly perceptible clock that is positioned on the vehicle.

20. The method of claim 19, wherein said step (2) comprises providing an oscillator for generating and issuing said second sequence of timing pulses that are spaced apart in time by said time interval value Δ

t₂, where said time interval value can be adjusted by varying a selected parameter θ

of the environment in which the oscillator is immersed.

21. The method of claim 20, wherein said step (3) comprises:

(3a) providing timing pulse comparison means, for receiving said first, second and third sequences of signals from said SATPS receiver/processor and the oscillator means, for determining and issuing a time interval difference Δ

t_diff =Δ

t₂ -Δ

t₃, where Δ

t₃ is a selected time interval value; and

(3b) providing pulse spacing control means, connected to said oscillator, for receiving the time interval difference signal Δ

t_diff and, if the magnitude of this signal Δ

t_diff is non-zero, for adjusting the selected environmental parameter θ

of the oscillator means to decrease the magnitude of the signal Δ

t_diff.

22. The method of claim 19, further comprising the step of providing differential corrections of SATPS signals that, when combined with said SATPS signals, provides at least one time fix that has an inaccuracy of at most about 3 nanoseconds.

23. The method of claim 19, further comprising the step of choosing said timing controlled instrument to be a telecommunications instrument that generates and transmits radiowave signals from said vehicle to a radiowave receiver that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

24. The method of claim 19, further comprising the step of choosing said timing controlled instrument to be a telecommunications instrument that receives radiowave signals at a radiowave receiver on said vehicle from a transmitter that is spaced apart from said vehicle, using signal transmission that is drawn from the class of signal transmission procedures consisting of asynchronous signal transmission, synchronous signal transmission and transmission of signals during one or more assigned time slots.

25. The method of claim 19, further comprising the step of choosing said Satellite Positioning System from the class of satellite-based location and time determination systems consisting of Global Positioning Systems and Global Orbiting Navigational Satellite Systems.