Abstract:
A position indicating system includes: a position indicating device, a first reference device, and a second reference device. The position indicating device includes: a first position indicating module for outputting a first signal; a second position indicating module for outputting a second signal; and a selecting module coupled to the first position indicating module and the second position indicating module for selectively driving the first position indicating module to output the first signal or driving the second position indicating module to output the second signal. The first reference device is corresponding to the first position indicating module for receiving the first signal and generating first position information according to a position of the position indicating device. And the second reference device is corresponding to the second position indicating module for receiving the second signal and generating second position information according to a position of the position indicating device.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a position indicating system, and more particularly, to a position indicating system capable of generating position information to a position-requesting device. 
   2. Description of the Prior Art 
   In today&#39;s society, there are many problems involving missing persons. Senior citizens with Alzheimer&#39;s disease and young children are at particular risk of going missing. Once a person has gone missing, there is no way to find them or to trace their current location. 
   Recent developments in technology have given rise to the global positioning system (GPS). As known by those skilled in the art, GPS utilizes co-ordinates of a plurality of satellites (including the spatial co-ordinates and the current time of the satellites) to accurately calculate the position of a receiver. In other words, a user can know their exact location through GPS. Even with the development of this technology, however, there has been no solution for the above-mentioned problem. 
   SUMMARY OF THE INVENTION 
   It is therefore one of the primary objectives of the claimed invention to provide a position indicating system having a plurality of position indicating mechanisms to solve the above-mentioned problem. 
   According to an exemplary embodiment of the claimed invention, a position indicating system is disclosed. The position indicating system comprises: a position indicating device, a first reference device, and a second reference device. The position indicating device comprises: a first position indicating module for outputting a first signal; a second position indicating module for outputting a second signal; and a selecting module electrically connected to the first position indicating module and the second position indicating module for selectively driving the first position indicating module to output the first signal or driving the second position indicating module to output the second signal. The first reference device is corresponding to the first position indicating module and utilized for receiving the first signal and generating first position information according to a position of the position indicating device. In addition, the second reference device is corresponding to the second position indicating module and utilized for receiving the second signal and generating second position information according to a position of the position indicating device. 
   According to another exemplary embodiment of the claimed invention, a position indicating system is disclosed. The position indicating system comprises: a position indicating device, a first reference device, and a second reference device. The position indicating device comprises: a first position indicating module for outputting a first signal; a second position indicating module for receiving a second signal and generating second position information corresponding to a position of the position indicating device according to the second signal; and a selecting module electrically connected to the first position indicating module and the second position indicating module for selectively driving the first position indicating module to output the first signal or driving the second position indicating module to receiving the second signal. The first reference device is corresponding to the first position indicating module and utilized for receiving the first signal and generating first position information of the position indicating device according to the first signal. In addition, the second reference device is corresponding to the second position indicating module and utilized for outputting the second signal. 
   The present invention can accurately determine the current location of the position indicating device and transmit position information to an external position requesting device. Therefore, a first user only has to carry the position indicating device, and another user who has the position requesting device can know the current location of the first user. Thus, the problem of missing persons can be solved. In addition, the present invention position indicating system can simultaneously utilize the wireless network, GPS, and radio frequency identification (RFID) techniques to determine the position of the position indicating device. The present invention position indicating system can therefore be utilized in any location to accurately determine the location of the position indicating device. 
   These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram of a first embodiment of a position indicating system according to the present invention. 
       FIG. 2  is a diagram of a second embodiment of a position indicating system according to the present invention. 
       FIG. 3  is a diagram of a third embodiment of a position indicating system according to the present invention. 
       FIG. 4  is a diagram of a fourth embodiment of a position indicating system according to the present invention. 
   

   DETAILED DESCRIPTION 
   Please refer to  FIG. 1 , which is a schematic diagram of a first embodiment of a position indicating system  10  according to the present invention. As shown in  FIG. 1 , the position indicating system  10  comprises a position indicating device  100 , and a surrounding installation  110 . The position indicating device  100  comprises a selecting module  210  and a plurality of position indicating modules. For example, as shown in  FIG. 1 , the position indicating device  100  can comprise a wireless local area network (WLAN) module  120 , a global positioning system (GPS) module  130 , a radio frequency identification (RFID) tag  140 , and a radio frequency identification (RFID) reader  150 . In addition, the surrounding installations  110  comprise a plurality of reference devices corresponding to the position indicating modules of the position indicating device. In this embodiment, the surrounding installations  110  comprises an access point (AP)  170  corresponding to the WLAN module  120 , an RFID reader  180  corresponding to the RFID tag  140 , and an RFID tag  190  corresponding to the RFID reader  150 . The function and the communication mechanism of the AP  170  and the WLAN module  120  and the function and the communication mechanism of the RFID tags  140  and  190  and the RFID readers  180  and  150  are well known by those skilled in the art, and thus omitted here. Furthermore, the GPS module  130  can communicate with a plurality of satellites  160 . Theoretically, the GPS module  130  can calculate the current position of the position indicating device  100  according to the data transferred from the satellites  160 . Please note that the related operations and the circuit designs of the GPS module  130  are also well known by those skilled in the art, and thus omitted here. 
   The functions and operations of the position indicating system  10  and the position indicating device  100  are illustrated as follows: first, an external position requesting device  200  transfers a position request to the position indicating device  100 . After the position indicating device  100  receives the position request, the WLAN module  120 , the GPS module  130 , the RFID tag  140 , and the RFID reader  150  are activated to search the surrounding installations  110  near the position indicating device  100  such that the position of the position indicating device  100  can be determined. 
   When the WLAN module is utilized in this embodiment, after the position indicating device  100  receives the position request, the WLAN module  120  determines whether an AP  170  is near the position indicating device  100 . If there is an AP  170  near the position indicating device  100 , the WLAN module  120  transfers a signal to the AP  170 . After the AP  170  receives the signal, the AP  170  transfers position information to the above-mentioned position requesting device  200 . The AP  170  can be a fixed-type AP, meaning that the AP  170  is always at a fixed position. Therefore, the AP  170  only has to transfer its IP address back such that the position of the position indicating device  100  can be traced. 
   For the GPS module  130 , after the position indicating device  100  receives the position request, the GPS module  130  utilizes the above-mentioned satellites  160  to calculate the current position of the position indicating device  100 , and then transfers position information of the position indicating device  100  back to the position requesting device  200 . 
   When the RFID tag  140  is utilized, because the RFID reader  180  can identify the RFID  140  inside the position indicating device  100 , the RFID reader  180  can be utilized to trace the position of the position indicating device  100  after the position indicating device  100  receives the position request. For example, after the RFID reader  180  identifies the RFID tag  140  inside the position indicating device  100 , the RFID reader  180  only has to transfer a signal back to the position requesting device  200 . Generally speaking, because the RFID reader  180  is also a fixed-type device, the position requesting device  200  can easily trace the current position of the position indicating device. Furthermore, because the effective distance that the RFID reader  180  can detect the RFID tag  140  is not long, if the position of the RFID reader  180  can be determined, this means that the current position of the position indicating device  100 , which is detected by the RFID reader  180 , can also be determined. 
   The function and operation of the RFID reader  150  are quite similar to the aforementioned RFID tag  140 . When the position indicating device  100  receives the position request, the RFID reader  150  identifies the RFID tag  190  near the position indicating device  100 , and transfers the information corresponding to the RFID tag  190  back to the position requesting device  200 . For example, the RFID device  150  identifies the fixed-type RFID tag  190  near the position indicating device  150  and detects an RFID tag  190  of a retail location. The position indicating device  200  can then easily trace the position of the RFID tag  190 , which also corresponds to the current position of the position indicating device  100 . 
   Furthermore, the selecting module  210  can select an appropriate module according to received signals. For example, the selecting module  210  can activate the inner WLAN module  120 , GPS module  130 , the RFID tag  140 , and the RFID reader  150  to search the surrounding installations in the neighborhood in order to determine the current position of the position indicating device  100 . If there is only an AP near the position indicating device  100  (that is, the surrounding installation only comprises the AP  170 , and the satellites  160 , RFID reader  180 , and RFID tag  190  are far away from the position indicating device  100 ), the selecting module  210  will only select the WLAN module  120  to communicate with the AP  170  and will disable other modules to save power. In other situations, the selecting module  210  can simultaneously select a plurality of modules (for example, the selecting module  210  can simultaneously select the WLAN  120  and the RFID tag  140 ) to determine the current position of the position indicating device  100  more accurately and generate corresponding position information. 
   Please note that the present invention does not limit the number of references devices including the AP  170 , the RFID reader  180 , and the RFID tag. In this embodiment, a single AP  170 , RFID reader  180 , and RFID tag is merely utilized as a preferred embodiment, but this is not a limitation of the present invention. For example, taking the WLAN module  120  into consideration, because the effective distance of the WLAN module  120  is long, only one AP  170  may not be enough for accurately determining the position of the position indicating device  100 . Therefore, multiple APs  170  can be utilized to accurately determine the position of the position indicating device  100 . Furthermore, the selecting module  210  is an optional device. That is, the present invention position indicating device  100  can still be implemented without the selecting module  210 , meaning the position indicating device  100  can directly receive the position request from the position requesting device  200  through each module without the selecting module, and receive signals from the surrounding installations in order to transfer back correct position information. 
   Please note that the above-mentioned position indicating modules, such as the WLAN module  120 , GPS module  130 , RFID tag  140 , and RFID reader  150  and corresponding reference devices, AP  170 , RFID reader  180 , and RFID tag  190 , can be designed selectively according to different product demands. Please refer to  FIG. 2 , which is a schematic diagram of a second embodiment of a position system  20  according to the present invention. As shown in  FIG. 2 , the position indicating system  20  comprises a position indicating device  201 , and a surrounding installation  202 . In this embodiment, the position indicating system  201  only comprises a WLAN module  220 , and the surrounding installation only comprises an AP  270 . In other words, the position indicating device  201  only utilizes the communication mechanism between the WLAN module  220  and the AP  270  to determine the current position of the position indicating device  201  and transmit corresponding information to the position requesting device  203 . 
   Please refer to  FIG. 3 , which is a diagram of a third embodiment of a position indicating system  30  according to the present invention. As shown in  FIG. 3 , the position indicating system  30  comprises a position indicating device  301 , and a surrounding installation  302 . In this embodiment, the position indicating device  301  only comprises an RFID tag  340 , and the surrounding installation  302  only comprises an RFID reader  380 . In other words, the position indicating device  301  only utilizes the communication mechanism between the RFID tag  340  and the RFID reader  380  to determine the current position of the position indicating device  301  and transmit corresponding information to the position requesting device  303 . 
   Please refer to  FIG. 4 , which is a diagram of a fourth embodiment of a position indicating system  40  according to the present invention. As shown in  FIG. 4 , the position indicating system  40  comprises a position indicating device  401 , and a surrounding installation  402 . In this embodiment, the position indicating device  401  only comprises an RFID reader  450 , and the surrounding installation  402  only comprises an RFID tag  490 . In other words, the position indicating device  401  only utilizes the communication mechanism between the RFID tag  490  and the RFID reader  450  to determine the current position of the position indicating device  401  and transmit corresponding information to the position requesting device  403 . 
   The present invention position indicating device  100  can comprise a subclass of the above-mentioned devices (modules), and the surrounding installation  120  only has to comprise corresponding subclasses of the above-mentioned devices such that the present invention can achieve the goal of tracing the position. This also belongs to the field of the present invention. 
   Please note that the present invention indicating device  100  can be a passive device. That is, before the position indicating device  100  receives the position request, the position indicating device  100  can be in a standby or a sleep mode to save power. The position indicating device  110  can also be an active device to actively transfer signals to the surrounding installation  120  in order to transfer position information to the position requesting device  200 . This also obeys the spirit of the present invention. 
   Please note that the present invention position indicating device  100  can be embedded in a cell phone, and the position requesting device  200  may comprise a communication device for outputting the above-mentioned position request, and a display device for displaying received position information. In an embodiment of the present invention, the position requesting device  200  can also be a cell phone. Therefore, the position information generated by the position indicating device  100  can be transferred to the position requesting device  200  through a well-known communication mechanism (for example, a cell phone message or an e-mail) of the cell phone. This also obeys the spirit of the present invention. 
   In contrast to the prior art, the present invention can accurately determine the current position of the position indicating device and generate position information to an external position requesting device. Therefore, a first user only has to carry the position indicating device, and another user who has the position requesting device can know the current position of the first user, effectively solving the missing persons problem. In addition, the present invention position indicating system can simultaneously utilize the wireless network, GPS, and RFID techniques to determine the position of the position indicating device. Therefore, the present invention position indicating system can be utilized in any location to accurately determine the position of the position indicating device. 
   Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.