BRIEF DESCRIPTION OF DRAWINGS
The foregoing and advantages of the invention will be appreciated more fully from the following further description thereof with reference to the accompanying drawings wherein:
FIG. 1 is a block diagram showing a conventional satellite positioning receiver.
FIG. 2 is a block diagram showing another conventional satellite positioning receiver.
FIG. 3 is a schematic diagram showing the power control device of the GPS receiver according to an embodiment of the present invention.
FIG. 4 shows a flow chart of a power control method for a GPS receiver according to the present invention.
FIG. 5 shows a flow chart executed by the power control module according to the present invention.
FIG. 6 shows another flow chart executed by the power control module according to the present invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
Referring to FIG. 3, FIG. 3 is a schematic diagram showing the power control device of the GPS receiver according to an embodiment of the present invention. As shown in FIG. 3, a power control device 30 for a GPS receiver according to the present invention includes a position sensor 32, e.g., gyroscope sensor or digital compass, and a power control module 34. The position sensor 32 is connected to the power control module 34 and is used to generate the position information. The power control module 34 selectively outputs the power to the GPS receiver 36 according to a variation quantity of the position information during a predetermined period.
In general, the power control device 30 and the GPS receiver 36 are both integrated in a mobile device (such as PDA) or vehicle. Therefore, the position information measured by the position sensor 32 of the power control device 30 is the same as that of the GPS receiver 36. Further, by determining whether the mobile device or the vehicle moves, the power control device 30 can infer whether the position information received by the GPS receiver 36 varies.
Accordingly, if the mobile device or vehicle does not move, it is inferred that the received position information does not vary. Since the position information does not vary, the power supplied to the GPS receiver 36 is temporarily turned off by the power control module 34, so as to lower the power consumption. Otherwise, as the mobile device or vehicle moves again, it is inferred that the position information varies. And the power control module 34 turns on the power supplied to the GPS receiver 36.
If it is determined by the power control module 34 that the position information does not vary for a predetermined amount of time, the power control module 34 will output an “OFF” power control signal 38 to the power switch 31. On the other hand, if it is determined that the position information varies, the power control module 34 will output an “ON” power control signal 38 to the power switch 31. The power switch 31 is connected among the power supply, GPS receiver 36, and power control module 34.
FIG. 4 shows a flow chart of a power control method for a GPS receiver according to the present invention. Firstly, a position sensor 32 and a power control module 34 are provided (S401). Secondly, the position sensor 32 generates the position information corresponding to the GPS receiver 36 and transmits the position information to the power control module 34 (S402). Thirdly, the power control module 34 selectively outputs the power to the GPS receiver 36 according to a variation quantity of the position information during a predetermined period of time (S403).
FIG. 5 shows a flow chart executed by the power control module 34 according to the present invention. The power control module 34 outputs an “ON” power control signal 38 to the power switch 31 (S501), such that the GPS receiver 36 is powered and starts to work. Then the process goes to step S502. In step S502, the power control module 34 determines whether the variation quantity of the azimuth is smaller than a first predetermined quantity for more than a first predetermined period of time. If the result is false, then the step S502 repeats. If the result is true, then the power control module 34 outputs an “OFF” power control signal 38 to the power switch 31 (S503), such that the GPS receiver is turned off and stops working. Then the process goes to step S504. In step S504, the power control module 34 determines whether the variation quantity of the azimuth is larger than a first predetermined quantity. If the result is false, then the step S504 repeats. If the result is true, then the process returns to step S501.
Specifically, since the position information provided by the position sensor 32 at least includes azimuth information, an “OFF” power control signal 38 is outputted to the power switch 31 when the variation quantity of the azimuth is smaller than a first predetermined quantity (such as 10 degrees) for more than a first predetermined period of time (such as 10 minutes). When the variation quantity of the azimuth is larger than a second predetermined quantity (such as 15 degrees), an “ON” power control signal 38 is outputted to the power switch 31 by the power control module 34.
FIG. 6 shows another flow chart executed by the power control module 34 according to the present invention. The power control module 34 outputs an “ON” power control signal 38 to the power switch 31 (S601), such that the GPS receiver 36 is powered and starts to work. Then the process goes to step S602. In step S602, the power control module 34 determines whether the variation quantity of the azimuth is smaller than a first predetermined quantity for more than a first predetermined period of time. If the result is false, then the step S602 repeats. If the result is true, then the power control module 34 outputs an “OFF” power control signal 38 to the power switch 31 (S603), such that the GPS receiver is turned off and stops working. Then the process goes to step S604. In step S604, the power control module 34 determines whether the variation quantity of the azimuth is larger than a first predetermined quantity for more than a second predetermined period of time. If the result is false, then the step S604 repeats. If the result is true, then the process returns to step S601.
In an embodiment of the present invention, to prevent the power control device 30 (especially the position sensor 32) from being touched inadvertently causing a large variation quantity of azimuth, in addition to the condition of set forth for algorithm in FIG. 5, a second predetermined period of time (such as 15 minutes) is introduced in step S604. In other words, when the variation quantity of azimuth is larger than the second predetermined quantity for more than a second predetermined period of time, the GPS receiver 36 is powered and starts to work again.
The above mentioned power switch 31 includes MOSFETs, or other electronic switch elements.
The above mentioned power control module 34 includes a microcontroller. The microcontroller 34 receives the position information and outputs an “OFF” or “ON” power control signal 38 by determining the variation quantity of the position information in a predetermined period of time. The processes in FIGS. 5 and 6 can be implemented by a firmware which is executed by the microcontroller.
While various exemplary embodiments of the present invention are described herein, it should be noted that the present invention may be embodied in other specific forms, including various modifications and improvements, without departing from the sprit and scope of the present invention. Thus, the described embodiments are to be considered in all respects only as illustrative and not restrictive.
Patent Application
20080012759
