WO2002088769A1 - Power managing apparatus for receiving of global positioning system - Google Patents

Power managing apparatus for receiving of global positioning system Download PDF

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Publication number
WO2002088769A1
WO2002088769A1 PCT/KR2002/000799 KR0200799W WO02088769A1 WO 2002088769 A1 WO2002088769 A1 WO 2002088769A1 KR 0200799 W KR0200799 W KR 0200799W WO 02088769 A1 WO02088769 A1 WO 02088769A1
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WO
WIPO (PCT)
Prior art keywords
code
processing means
signals
power
navigation data
Prior art date
Application number
PCT/KR2002/000799
Other languages
French (fr)
Inventor
Sangjeong Lee
Chansik Park
Youngbaek Kim
Seokbo Son
Hungseok Seo
Sungwook Moon
Ilheung Choi
Sanghyun Park
Jongpil Lee
Original Assignee
Navicom Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Navicom Co., Ltd. filed Critical Navicom Co., Ltd.
Publication of WO2002088769A1 publication Critical patent/WO2002088769A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/34—Power consumption
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/30—Acquisition or tracking or demodulation of signals transmitted by the system code related

Definitions

  • the present invention relates to a power managing apparatus for a receiver of Global Positioning System
  • GPS receiver' a power managing apparatus being capable of reducing a power consumption of the GPS receiver.
  • Fig. 1 is a block diagram of a conventional GPS receiver, wherein a digital signal processor (hereinafter X DSP' ) unit 12, provided with digital signals of intermediate frequency from an intermediate frequency (hereinafter ⁇ IF' ) unit 10, processes the digital signals for use in processing a navigation data and . provides processed digital signals to a navigation data processing unit 18.
  • the DSP unit 12 includes a correlator 14 and a real time clock (hereinafter ⁇ RTC ) unit 16.
  • Fig. 2 is a block diagram illustrating an example of the correlator 14 shown in Fig. 1.
  • the correlator 14 comprises a carrier numerically controlled oscillator (hereinafter 'carrier NCO' ) 22, a first carrier mixer 24, a second carrier mixer 26, a code numerically _ controlled oscillator (hereinafter 'code NCO' ) 28, a C/A code generator 30, a first to a sixth code mixers 32, 34, 36, 44, 46, 48, and a first to a sixth integrators 38, 40, 42, 50, 52, 54.
  • 'carrier NCO' carrier numerically controlled oscillator
  • first carrier mixer hereinafter 'carrier mixer 24
  • a second carrier mixer 26
  • a code numerically _ controlled oscillator hereinafter 'code NCO'
  • C/A code generator 30 a first to a sixth code mixers 32, 34, 36, 44, 46, 48, and a first to a sixth integrators 38, 40, 42,
  • the IF unit 10 converts radio frequency signals received from satellites into IF signals, and provides the IF signals for the correlator 14 in the DSP unit 12.
  • the carrier NCO 22 generates sinusoidal waves for use in eliminating carrier waves received from satellite signals.
  • the frequency of carrier wave provided from the navigation data processing unit 18 is inputted.
  • sine signals (I) and cosine signals (Q) are generated and provided for the first carrier mixer 24 and the second carrier mixer 26, respectively.
  • the first carrier mixer 24 multiplies the sine signals (I) provided from the carrier NCO 24 by the digital signals of IF, and provides multiplied signals for the first, the second and the third code mixer 32, 34 and 36, respectively.
  • the code NCO 28 generates a reference frequency for use in generating a pseudo random noise (hereinafter ⁇ PRN') code of GPS satellites, and provides the reference frequency for the C/A code generator 30.
  • the C/A code generator 30 generates the PRN codes of the GPS satellites by using the reference frequency provided from the code generator 28.
  • the C/A code generator generates an early code, a prompt code_ and a late code, and provides the early code, the prompt code and the late code for the first, the second and the third code mixers 32, 34 and 36, respectively.
  • the first code mixer 32 multiplies the early code received from the C/A code mixer 30 by output signals from the first carrier mixer 24, and provides multiplied signals to the first integrator 38.
  • the first integrator 38 integrates an output of the first code mixer 32 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18.
  • the C/A code is the PRN code of the GPS satellite.
  • the second code mixer 34 multiplies the prompt code received from the C/A code mixer 30 by output signals from the first carrier mixer 24, and provides multiplied signals to the second integrator 40.
  • the second integrator 40 integrates an output of the second code mixer 34 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18.
  • the third code mixer 36 multiplies the late code received from the C/A code mixer 30 by output signals from the first carrier mixer 24, and provides multiplied signals to the third integrator 42.
  • the third integrator 42 integrates an output of the third code mixer 36 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18.
  • each of the fourth, fifth and sixth code mixer 44, 46, 48 multiplies an early code, a prompt code and a late code received from the C/A code mixer 30 by output signals of the second carrier mixer 26, and provides multiplied signals to the fourth, the fifth and the sixth integrator 50, 52 and 54 respectively.
  • Each of the fourth, the fifth and the sixth integrator integrates an output of the fourth, the fifth and the sixth code mixer 44, 46 and 48 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18, respectively.
  • the GPS receiver continuously consumes power even after acquiring a required data, and thus, the GPS receiver exacts unnecessarily high . power consumption.
  • An object of the present invention is to provide a power managing apparatus for the GPS receiver for preventing unnecessary power consumption of the GPS receiver by fast receiving signals from the satellites through estimating power break time being estimated by using a correction function for real time clock and simultaneous search of a plurality of code phases corresponding to GPS signal.
  • a power managing system for a GPS receiver comprising: an intermediate frequency generating means for generating a intermediate frequency by converting a radio frequency of signals received from a satellite to the intermediate frequency; a digital signal processing means for processing intermediate frequency signals provided by the intermediate frequency generating means to be used in a navigation data processes; a navigation data processing means for calculating satellite navigation data based on a processed digital signals from the digital signal processing means, estimating a power break time, and generating a power control signals capable of providing power to the intermediate frequency generating means and the digital signal processing means only when satellite data required for a calculation of the satellite navigation data is received; and a power supply means for controlling a power supply " to the intermediate frequency generating means and the digital signal processing means on the basis of the power control signals provided from the navigation data processing means.
  • Fig. 1 is a block diagram showing a conventional GPS receiver
  • Fig. 2 is a block diagram illustrating an exemplary structure of a correlator in Fig. 1;
  • Fig. 3 is a block diagram showing an embodiment of a power managing apparatus for GPS receiver in accordance with the present invention
  • Fig. 4 is a graph describing an algorithm used in the power managing apparatus for GPS receiver of Fig. 3;
  • Fig. 5 is a timing diagram describing a principle of an estimation of a power break time for use in the GPS receiver shown in Fig. 3; 20 Fig. 6 is a diagram showing an embodiment of a real time clock application unit illustrated in Fig. 3;
  • Fig. 7 and Fig. 8 are timing diagrams for describing an operation of the real time clock application unit shown in Fig. 6; and 25 Fig. 9 is a block diagram illustrating an embodiment of a correlator shown in Fig. 3. Best Mode for Carrying Out the Invention
  • Fig. 3 is a block diagram showing an embodiment of a power managing apparatus for GPS receiver in accordance with the present invention.
  • a navigation data processing means 118 receives output signals received from a digital signal processing means 112 and calculates a satellite navigation data by using the output signals.
  • the navigation data processing means 118 controls a power supply means 120 so that the power supply means 120 provides power to an intermediate frequency generating means 110 and the digital signal processing means 112 once satellite data required for calculation of the satellite navigation data is received.
  • the digital signal processing means 112 includes a correlator 114 and a real time clock application unit 116.
  • Fig. 4 is a graph describing an algorithm of the power managing apparatus for GPS receiver shown in Fig. 3.
  • the digital signal processing means 112 generates signals as shown in Fig. 5b from satellite signals as shown in Fig. 5a
  • the navigation data processing means 118 estimates the power break time by using a correction function for real time clock of the real time clock application unit 116.
  • the navigation data processing means 118 controls the power supply means 120 to intermittently supply power for the intermediate frequency generating means 110 and the digital signal processing means 112 based on the estimated power break time.
  • the real time clock application unit 116 corrects the real time clock by using a clock source of the GPS receiver.
  • the clock source of the GPS receiver for example, may be a main clock of the digital application processing means 112.
  • the intermediate frequency generating means 110 and the digital signal processing means 112 are supplied with power from the power supply means 120, and operate only while information required for a navigation calculation is received from satellites.
  • Symbols RF' , V DSP' and 'CPU' shown in Fig. 4 mean the intermediate frequency generating means 110, the digital signal processing means 112 and the navigation data processing means 118, respectively.
  • Precise estimation of the power break time or power supply interruption time is required in order to maintain a signal synchronization.
  • a method for estimating the power break time by using the real time clock may be used.
  • various crystal oscillators used for the real time clock have different frequencies which may differ from a product to another, and further frequency characteristics of each crystal oscillator may vary with time.
  • the real time clock application unit 116 comprises a write register 60, a frequency measuring unit 62, a power supply control unit 64 for controlling power supply time and a read register 66.
  • the write register 60 provides the frequency measuring unit 62 with an initial value of a calibration counter set as illustrated in Fig. 7d and signals as illustrated in Fig. 8b.
  • the write register 60 provides a wake-up time for the navigation data processing means 118 for the control unit 64 as shown in Fig. 7e.
  • the frequency measuring unit 62 estimates frequencies of the real time clock.
  • the frequency measuring unit 62 counts the number of main clocks within the real time clocks, as shown in Fig. 7a, defined by a user and provided from an outside, and transfers the number of the main clocks to the navigation data processing means 118 via the read register 66.
  • the power supply control unit 64 controls a power supply time, in particular, receives the wake-up time of the navigation data processing means 118 from the write register 60 and transfers signals as shown in Fig. 7f to the navigation data processing means 118. For example, if the navigation data processing means 118 sets a value of "7" for the wake-up time, the power supply control unit 64 provides signals as shown in Fig.7f to the navigation data processing means 118 after seven clocks of the real time clock as Fig. 7a. The signals- as shown in Fig. 7b are provided fro an " outside. The signals as shown in Fig.7f may be used . as an interrupt of the navigation data processing means 118.
  • the signals as depicted in Fig. 8c are internal signals as a down counter using the real time clock as shown in Fig. 8a, and the signals in Fig. 8d are maintained at a value of "1" during the signals of Fig. 8c are hot zero.
  • the signals as shown in Fig. 8g are internal signals for transferring the main clock while the signals of Fig. 8d remain “1" level.
  • the signals as shown in Fig. 8h keep count by using the main clocks transferred. Latching and clearing operations of signals may be performed by using the internal signals as shown in Fig. 8e and Fig. 8f. Latched signals are transferred to the read register 66.
  • a signal processor in accordance with the present invention is designed to be 0 capable of maintaining synchronization by using a plurality of integrators despite the existence of an error ranging ⁇ 5 microseconds .
  • Fig.9 is a block diagram illustrating an example of the correlator 114 as shown in Fig. 3, wherein the
  • correlator comprises a carrier generator 70, a first carrier mixer 72, a second carrier mixer 74, a code generator 76, a multi-phase C/A code generator 78, a first to a thirty-second code mixers 80-84, 92-96, and a first to a thirty-second integrator 86-90, 98-102.
  • the carrier generator 70 generates sinusoidal signals used for eliminating a carrier wave from satellite signals.
  • the .carrier generator 70 inputs the frequency provided for the navigation data processing means 118, generates sine signals (I) and cosine signals (Q) , and
  • the 25 provides the sine and cosine signals to the first and second carrier mixers 72 and 74, respectively.
  • the first carrier mixer 72 multiplies the sine signals (I) from the carrier generator 70 by a digital intermediate frequency from the intermediate frequency generating means 110, and provides multiplied signals for the first to the sixteenth code mixers 80-84.
  • the code generator 76 generates a reference frequency used for generating a PRN code of GPS, and feeds the reference frequency to the multi-phase C/A code generator 78.
  • the multi-phase C/A code generator 78 generates 16 numbers of PRN codes with different phase each other by using the reference frequency from the code generator 76, and provides the PRN codes for the first to the thirty- second code mixers 80-96.
  • the first code mixer 80 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the first carrier mixer 72, and consequently, provides multiplied signals for the first integrator 86.
  • the first integrator 86 integrates an output of the first code mixer 80 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing means 118.
  • the second code mixer 82 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the first carrier mixer 72, and provides multiplied signals ' for the second integrator 88.
  • the second integrator 88 integrates an output of the second code mixer 82 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing means 118.
  • the sixteenth code mixer 84 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the first carrier mixer 72, and provides multiplied signals for the sixteenth integrator 90.
  • the sixteenth integrator 90 integrates an output of the sixteenth code mixer 84 during one period of a C/A code, i.e., .1 millisecond, and provides an integration result for the navigation data processing means 118.
  • each of the seventeenth, the thirty-first and the thirty-second code mixers 92, 94, and 96 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the second carrier mixer 74, and provides multiplied signals for the seventeenth, the thirty-first and the thirty-second integrators 98, 100 and 102.
  • Each of the seventeenth, the thirty-first and the thirty-second integrators 98, 100 and 102 integrates an output of the seventeenth, the thirty-first and the thirty-second code mixers 92, 94_ and 96 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing means 118.
  • the power supply means 120 controls power supplied to the intermediate frequency generating means 110 and the digital signal processing means 112 pursuant to power control signals provided from the navigation data processing means 118.

Abstract

The present invention relates to a power managing apparatus for used in GPS receiver, capable of reducing power consumption. There is provided a power managing apparatus for preventing unnecessary power consumption of a GPS receiver by fast receiving signals from the satellites through estimating power break time. The power break time can be estimated by using a correction function for real time clock and simultaneous search of a plurality of code phase correspondent to GPS signal.

Description

POWER MANAGING APPARATUS FOR RECEIVING OF GLOBAL POSITIONING SYSTEM
Technical Field
The present invention relates to a power managing apparatus for a receiver of Global Positioning System
(hereinafter ΛGPS receiver' ) , and more particularly to a power managing apparatus being capable of reducing a power consumption of the GPS receiver.
Background Art
Fig. 1 is a block diagram of a conventional GPS receiver, wherein a digital signal processor (hereinafter XDSP' ) unit 12, provided with digital signals of intermediate frequency from an intermediate frequency (hereinafter ΛIF' ) unit 10, processes the digital signals for use in processing a navigation data and . provides processed digital signals to a navigation data processing unit 18. The DSP unit 12 includes a correlator 14 and a real time clock (hereinafter λRTC ) unit 16.
The conventional GPS receiver will be described in detail with reference to 'Fig. 2.
Fig. 2 is a block diagram illustrating an example of the correlator 14 shown in Fig. 1. The correlator 14 comprises a carrier numerically controlled oscillator (hereinafter 'carrier NCO' ) 22, a first carrier mixer 24, a second carrier mixer 26, a code numerically _ controlled oscillator (hereinafter 'code NCO' ) 28, a C/A code generator 30, a first to a sixth code mixers 32, 34, 36, 44, 46, 48, and a first to a sixth integrators 38, 40, 42, 50, 52, 54.
In Fig. 1 and Fig. 2, the IF unit 10 converts radio frequency signals received from satellites into IF signals, and provides the IF signals for the correlator 14 in the DSP unit 12.
The carrier NCO 22 generates sinusoidal waves for use in eliminating carrier waves received from satellite signals. In detail, the frequency of carrier wave provided from the navigation data processing unit 18 is inputted. Then, sine signals (I) and cosine signals (Q) are generated and provided for the first carrier mixer 24 and the second carrier mixer 26, respectively.
The first carrier mixer 24 multiplies the sine signals (I) provided from the carrier NCO 24 by the digital signals of IF, and provides multiplied signals for the first, the second and the third code mixer 32, 34 and 36, respectively.
The code NCO 28 generates a reference frequency for use in generating a pseudo random noise (hereinafter ΛPRN') code of GPS satellites, and provides the reference frequency for the C/A code generator 30. The C/A code generator 30 generates the PRN codes of the GPS satellites by using the reference frequency provided from the code generator 28. In detail, the C/A code generator generates an early code, a prompt code_ and a late code, and provides the early code, the prompt code and the late code for the first, the second and the third code mixers 32, 34 and 36, respectively.
The first code mixer 32 multiplies the early code received from the C/A code mixer 30 by output signals from the first carrier mixer 24, and provides multiplied signals to the first integrator 38. The first integrator 38 integrates an output of the first code mixer 32 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18. The C/A code is the PRN code of the GPS satellite.
The second code mixer 34 multiplies the prompt code received from the C/A code mixer 30 by output signals from the first carrier mixer 24, and provides multiplied signals to the second integrator 40. The second integrator 40 integrates an output of the second code mixer 34 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18.
The third code mixer 36 multiplies the late code received from the C/A code mixer 30 by output signals from the first carrier mixer 24, and provides multiplied signals to the third integrator 42. The third integrator 42 integrates an output of the third code mixer 36 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18.
Similarly, each of the fourth, fifth and sixth code mixer 44, 46, 48 multiplies an early code, a prompt code and a late code received from the C/A code mixer 30 by output signals of the second carrier mixer 26, and provides multiplied signals to the fourth, the fifth and the sixth integrator 50, 52 and 54 respectively. Each of the fourth, the fifth and the sixth integrator integrates an output of the fourth, the fifth and the sixth code mixer 44, 46 and 48 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing unit 18, respectively.
According to the above-described prior art, however, the GPS receiver continuously consumes power even after acquiring a required data, and thus, the GPS receiver exacts unnecessarily high.power consumption.
Disclosure of Invention
An object of the present invention is to provide a power managing apparatus for the GPS receiver for preventing unnecessary power consumption of the GPS receiver by fast receiving signals from the satellites through estimating power break time being estimated by using a correction function for real time clock and simultaneous search of a plurality of code phases corresponding to GPS signal.
According to an aspect of the present invention, there is provided a power managing system for a GPS receiver comprising: an intermediate frequency generating means for generating a intermediate frequency by converting a radio frequency of signals received from a satellite to the intermediate frequency; a digital signal processing means for processing intermediate frequency signals provided by the intermediate frequency generating means to be used in a navigation data processes; a navigation data processing means for calculating satellite navigation data based on a processed digital signals from the digital signal processing means, estimating a power break time, and generating a power control signals capable of providing power to the intermediate frequency generating means and the digital signal processing means only when satellite data required for a calculation of the satellite navigation data is received; and a power supply means for controlling a power supply" to the intermediate frequency generating means and the digital signal processing means on the basis of the power control signals provided from the navigation data processing means. Brief Description of Drawings
The above and other objects and features of the 5 present invention will become apparent from the following description of a preferred "embodiment given in conjunction with the accompanying drawings, in which:
Fig. 1 is a block diagram showing a conventional GPS receiver; 10 Fig. 2 is a block diagram illustrating an exemplary structure of a correlator in Fig. 1;
Fig. 3 is a block diagram showing an embodiment of a power managing apparatus for GPS receiver in accordance with the present invention; 15.. Fig. 4 is a graph describing an algorithm used in the power managing apparatus for GPS receiver of Fig. 3;
Fig. 5 is a timing diagram describing a principle of an estimation of a power break time for use in the GPS receiver shown in Fig. 3; 20 Fig. 6 is a diagram showing an embodiment of a real time clock application unit illustrated in Fig. 3;
Fig. 7 and Fig. 8 are timing diagrams for describing an operation of the real time clock application unit shown in Fig. 6; and 25 Fig. 9 is a block diagram illustrating an embodiment of a correlator shown in Fig. 3. Best Mode for Carrying Out the Invention
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 3 is a block diagram showing an embodiment of a power managing apparatus for GPS receiver in accordance with the present invention. In the power managing apparatus for GPS receiver in Fig. 3, a navigation data processing means 118 receives output signals received from a digital signal processing means 112 and calculates a satellite navigation data by using the output signals. In addition, the navigation data processing means 118 controls a power supply means 120 so that the power supply means 120 provides power to an intermediate frequency generating means 110 and the digital signal processing means 112 once satellite data required for calculation of the satellite navigation data is received. The digital signal processing means 112 includes a correlator 114 and a real time clock application unit 116.
The power managing apparatus in accordance with the present invention will be described in more detail with reference to Fig. 4 to Fig. 9. Fig. 4 is a graph describing an algorithm of the power managing apparatus for GPS receiver shown in Fig. 3. In Fig. 4, the digital signal processing means 112 generates signals as shown in Fig. 5b from satellite signals as shown in Fig. 5a, the navigation data processing means 118 estimates the power break time by using a correction function for real time clock of the real time clock application unit 116. In addition, the navigation data processing means 118 controls the power supply means 120 to intermittently supply power for the intermediate frequency generating means 110 and the digital signal processing means 112 based on the estimated power break time. The real time clock application unit 116 corrects the real time clock by using a clock source of the GPS receiver. The clock source of the GPS receiver, for example, may be a main clock of the digital application processing means 112. Thus, the intermediate frequency generating means 110 and the digital signal processing means 112 are supplied with power from the power supply means 120, and operate only while information required for a navigation calculation is received from satellites. Symbols RF' , VDSP' and 'CPU' shown in Fig. 4 mean the intermediate frequency generating means 110, the digital signal processing means 112 and the navigation data processing means 118, respectively.
Precise estimation of the power break time or power supply interruption time is required in order to maintain a signal synchronization. For a precise estimation of the power break time, a method for estimating the power break time by using the real time clock may be used. In general, however, various crystal oscillators used for the real time clock have different frequencies which may differ from a product to another, and further frequency characteristics of each crystal oscillator may vary with time. Thus, it is difficult to maintain the signal synchronization by using a nominal frequency value presented by an oscillator manufacturer. Therefore, an extra means is required to estimate an oscillator frequency used in a real time application.
Referring to Fig. 6, the real time clock application unit 116 comprises a write register 60, a frequency measuring unit 62, a power supply control unit 64 for controlling power supply time and a read register 66.
As shown in Fig.6, the write register 60 provides the frequency measuring unit 62 with an initial value of a calibration counter set as illustrated in Fig. 7d and signals as illustrated in Fig. 8b. In addition, the write register 60 provides a wake-up time for the navigation data processing means 118 for the control unit 64 as shown in Fig. 7e.
The frequency measuring unit 62 estimates frequencies of the real time clock. In detail, the frequency measuring unit 62 counts the number of main clocks within the real time clocks, as shown in Fig. 7a, defined by a user and provided from an outside, and transfers the number of the main clocks to the navigation data processing means 118 via the read register 66.
The power supply control unit 64 controls a power supply time, in particular, receives the wake-up time of the navigation data processing means 118 from the write register 60 and transfers signals as shown in Fig. 7f to the navigation data processing means 118. For example, if the navigation data processing means 118 sets a value of "7" for the wake-up time, the power supply control unit 64 provides signals as shown in Fig.7f to the navigation data processing means 118 after seven clocks of the real time clock as Fig. 7a. The signals- as shown in Fig. 7b are provided fro an" outside. The signals as shown in Fig.7f may be used . as an interrupt of the navigation data processing means 118.
The signals as depicted in Fig. 8c are internal signals as a down counter using the real time clock as shown in Fig. 8a, and the signals in Fig. 8d are maintained at a value of "1" during the signals of Fig. 8c are hot zero.
The signals as shown in Fig. 8g are internal signals for transferring the main clock while the signals of Fig. 8d remain "1" level. The signals as shown in Fig. 8h keep count by using the main clocks transferred. Latching and clearing operations of signals may be performed by using the internal signals as shown in Fig. 8e and Fig. 8f. Latched signals are transferred to the read register 66.
Though, however, estimation of a frequency of a clock used for a real time application is readily obtainable by 5 using the frequency measuring unit 62, an estimation error may increase in proportion to the increase of the power break time because of time-varying characteristics of the crystal oscillator. Therefore, a signal processor in accordance with the present invention is designed to be 0 capable of maintaining synchronization by using a plurality of integrators despite the existence of an error ranging ±5 microseconds .
Fig.9 is a block diagram illustrating an example of the correlator 114 as shown in Fig. 3, wherein the
15 correlator comprises a carrier generator 70, a first carrier mixer 72, a second carrier mixer 74, a code generator 76, a multi-phase C/A code generator 78, a first to a thirty-second code mixers 80-84, 92-96, and a first to a thirty-second integrator 86-90, 98-102.
2.0 In Fig. 9, the carrier generator 70 generates sinusoidal signals used for eliminating a carrier wave from satellite signals. The .carrier generator 70 inputs the frequency provided for the navigation data processing means 118, generates sine signals (I) and cosine signals (Q) , and
25 provides the sine and cosine signals to the first and second carrier mixers 72 and 74, respectively. The first carrier mixer 72 multiplies the sine signals (I) from the carrier generator 70 by a digital intermediate frequency from the intermediate frequency generating means 110, and provides multiplied signals for the first to the sixteenth code mixers 80-84.
The code generator 76 generates a reference frequency used for generating a PRN code of GPS, and feeds the reference frequency to the multi-phase C/A code generator 78. The multi-phase C/A code generator 78 generates 16 numbers of PRN codes with different phase each other by using the reference frequency from the code generator 76, and provides the PRN codes for the first to the thirty- second code mixers 80-96. The first code mixer 80 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the first carrier mixer 72, and consequently, provides multiplied signals for the first integrator 86. The first integrator 86 integrates an output of the first code mixer 80 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing means 118.
The second code mixer 82 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the first carrier mixer 72, and provides multiplied signals 'for the second integrator 88. The second integrator 88 integrates an output of the second code mixer 82 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing means 118. The sixteenth code mixer 84 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the first carrier mixer 72, and provides multiplied signals for the sixteenth integrator 90. The sixteenth integrator 90 integrates an output of the sixteenth code mixer 84 during one period of a C/A code, i.e., .1 millisecond, and provides an integration result for the navigation data processing means 118.
Similarly, each of the seventeenth, the thirty-first and the thirty-second code mixers 92, 94, and 96 multiplies the PRN code from the multi-phase C/A code generator 78 by an output of the second carrier mixer 74, and provides multiplied signals for the seventeenth, the thirty-first and the thirty-second integrators 98, 100 and 102. Each of the seventeenth, the thirty-first and the thirty-second integrators 98, 100 and 102 integrates an output of the seventeenth, the thirty-first and the thirty-second code mixers 92, 94_ and 96 during one period of a C/A code, i.e., 1 millisecond, and provides an integration result for the navigation data processing means 118. The power supply means 120 controls power supplied to the intermediate frequency generating means 110 and the digital signal processing means 112 pursuant to power control signals provided from the navigation data processing means 118.
Industrial Applicability
In accordance with the present invention, it is' possible to fast acquire signals from satellites by using the power break time estimated by a correction function for a real time clock and simultaneous search of a plurality of code phase corresponding to GPS signals, and thus to prevent unnecessary power consumption of a GPS receiver.

Claims

What is claimed is:
1. A power managing apparatus for a GPS receiver comprising: an intermediate frequency generating means for converting an intermediate a radio frequency received from a satellite into an intermediate frequency signals; a digital signal processing means for generating processed digital signals by processing the intermediate frequency signal provided by the intermediate frequency generating means to be used in a navigation data processes, and performing a correction of a real time clock; a navigation data processing means for calculating satellite navigation data based on the processed digital signals from the digital signal processing means, estimating a power break time, and generating power control signals for use in providing power to the intermediate frequency generating means and the digital signal processing means only when satellite data required for a calculation of the satellite navigation data is received; and a power supply means for controlling a power supplied to the intermediate frequency generating means and the digital signal processing means on the basis of the power control signals provided from the navigation data processing means.
2. The apparatus as claimed in claim 1, the power break time of the navigation data processing means is estimated and determined by using both the correction of the real time clock of the digital signal processing means and search of a plurality of code phase correspondent to a pseudo random noise (PRN) code of satellite data from the satellite.
3. The apparatus as claimed in claim 1 or 2, the correction of the real time clock is performed by using a clock source of the GPS receiver.
PCT/KR2002/000799 2001-04-30 2002-04-29 Power managing apparatus for receiving of global positioning system WO2002088769A1 (en)

Applications Claiming Priority (2)

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KR1020010023359A KR20020083747A (en) 2001-04-30 2001-04-30 Power managing apparatus for receiver of global positioning system
KR2001/23359 2001-04-30

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KR100835958B1 (en) 2007-02-12 2008-06-10 삼성전자주식회사 Navigator and method for reducing current thereof

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Cited By (7)

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Publication number Priority date Publication date Assignee Title
US8707458B2 (en) 2004-07-07 2014-04-22 Nariste Networks Pty. Ltd. Location-enabled security services in wireless network
US9277400B2 (en) 2004-07-07 2016-03-01 Nariste Networks Pty. Ltd. Location-enabled security services in wireless network
WO2006024112A1 (en) * 2004-09-02 2006-03-09 Nariste Networks Pty Ltd Self monitoring gps on mobile device
AU2005279635B2 (en) * 2004-09-02 2010-06-10 Nariste Networks Pty Ltd Self monitoring GPS on mobile device
US8022870B2 (en) 2004-09-02 2011-09-20 Nariste Networks Pty Ltd Self monitoring GPS on mobile device
USRE46237E1 (en) 2004-09-02 2016-12-13 Nariste Networks Pty Ltd Self monitoring GPS on mobile device
USRE48206E1 (en) 2004-09-02 2020-09-15 Robert Anderson Malaney Reduced power use in mobile GPS-based technologies

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