Abstract:
A group global positioning system includes a plurality of positioning signal processing devices with a global positioning function and a plurality of radio signal processing devices corresponding to the positioning signal processing devices. With one of the corresponding radio signal processing devices, one of the positioning signal processing devices outputs analog global positioning information to the remaining ones of the positioning signal processing devices which then performs analog-to-digital conversion on the analog global positioning information and recovers digital global positioning information, thus allowing the remaining ones of the positioning signal processing devices to execute the global positioning function and display related information. The present invention discloses a grouping technique for simultaneously displaying on the positioning signal processing devices the digital global positioning information thereof.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to global positioning systems, and more particularly, to a group global positioning system. 
     2. Description of the Prior Art 
     A global positioning system (GPS) is typically used for performing a positioning operation. The positioning operation involves comparing geographic location coordinates with road/street data stored in a road/street database (i.e. e-maps), calculating the data related to a road/street where a portable electronic device is presently located and the data related to the actual geographic location of the portable electronic device, and displaying the data. Global positioning systems nowadays are widely used in vehicle-oriented road/street positioning devices for positioning any moving vehicle. The positioning function of the global positioning systems is increasingly integrated into portable electronic devices like cellular phones and PDAs. 
     Nevertheless, the aforesaid positioning function configured for just a single tool is never adequate to meet a need. For instance, if a member of a group tour of sparsely populated places (for example, deserts and mountains) lags behind her or his fellow tour members, the slow tour member can identify her or his own geographic location, using an electronic device with a positioning function, but s/he will not be able to know the geographic location of her or his fellow tour members, and in consequence s/he will be prevented from hurrying to catch up. On the other hand, her or his fellow tour members fail to lend a helping hand to the slow tour member, as they have no idea about the slow tour member&#39;s current geographic location. Another problem is that a tour organizer is ignorant of the current geographic location of individual tour members, and thus the tour organizer fails to know whether the group tour is underway as scheduled. 
     Accordingly, an issue calling for urgent action is related to development of a global positioning technology to overcome the aforesaid drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     In light of the aforesaid drawbacks of the prior art, it is a primary objective of the present invention to provide a group global positioning system whereby a member of a group is informed of her or his fellow group members&#39; geographic locations. 
     Another objective of the present invention is to provide a group global positioning system to facilitate a group activity. 
     In order to achieve the above and other objectives, the present invention provides a group global positioning system. The group global positioning system comprises a plurality of positioning signal processing devices and a plurality of radio signal processing devices. The positioning signal processing devices have a global positioning function and each comprise a positioning signal processing module for executing the global positioning function and receiving digital global positioning information sent by a satellite while executing the global positioning function, a first signal conversion module for performing digital-to-analog conversion on the digital global positioning information and outputting analog global positioning information, and a second signal conversion module for performing analog-to-digital conversion. The radio signal processing devices correspond to the positioning signal processing devices and output, by radio transmission, the analog global positioning information outputted by the first signal conversion module. With one of the corresponding radio signal processing devices, one of the positioning signal processing devices sends to the remaining ones of the positioning signal processing devices the analog global positioning information outputted by the first signal conversion module, allowing the second signal conversion module of the remaining ones of the positioning signal processing devices to perform the analog-to-digital conversion on the analog global positioning information and recover the digital global positioning information, thus enabling the positioning signal processing module of the remaining ones of the positioning signal processing devices to execute the global positioning function and display related information. 
     In the preferred embodiment of the present invention, the positioning signal processing devices are selected from the group consisting of personal digital assistants (PDAs), cellular phones, and computers, all of which are installed with navigator software which supports a global positioning system (GPS). The digital global positioning information comprises a geographic location message. The positioning signal processing module is a global positioning system module (GPS module). The first signal conversion module is a digital-to-analog converter (D/A converter). The second signal conversion module is an analog-to-digital converter (A/D converter). The radio signal processing devices are radio communication devices which comprise a radio module each. 
     Compared to the prior art, the group global positioning system of the present invention works as follows. With one of the corresponding radio signal processing devices, one of the positioning signal processing devices outputs analog global positioning information to the remaining ones of the positioning signal processing devices, allowing the remaining ones of the positioning signal processing devices to perform the analog-to-digital conversion on the analog global positioning information and recover the digital global positioning information, thus enabling the remaining ones of the positioning signal processing devices to execute the global positioning function and display related information. Accordingly, with the group global positioning system of the present invention, a member of a group can be informed of her or his fellow members&#39; geographic locations such that a group activity is well-coordinated and well-controlled, thus preventing the group members from falling behind or getting lost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The FIGURE is a functional block diagram of a group global positioning system of the preferred embodiment according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention is herein illustrated with a specific embodiment so that one skilled in the pertinent art can easily understand other advantages and effects of the present invention from the disclosure of the invention. 
     Referring to the FIGURE, which is a functional block diagram of a group global positioning system  1  of the preferred embodiment according to the present invention. The group global positioning system  1  comprises a plurality of positioning signal processing devices  10 , a plurality of radio signal processing devices  11  corresponding to the positioning signal processing devices  10 , and a configuration module  12 . The number of the positioning signal processing devices  10  may vary if necessary. The number of the radio signal processing devices  11  equals the number of the positioning signal processing devices  10 . In the preferred embodiment, the number of the positioning signal processing devices  10  and that of the radio signal processing devices  11  are three, but the quantity of the positioning signal processing devices  10  and that of the radio signal processing devices  11  in practice should not be limited by the preferred embodiment. 
     The details of the group global positioning system  1  of the present invention are as follows: The positioning signal processing devices  10  have a global positioning function and each comprise a positioning signal processing module  100  for executing the global positioning function and receiving digital global positioning information sent by a satellite while executing the global positioning function, a first signal conversion module  101  for performing digital-to-analog conversion on the digital global positioning information and outputting analog global positioning information, and a second signal conversion module  102  for performing analog-to-digital conversion. In the preferred embodiment, the positioning signal processing devices  10  are selected from the group consisting of personal digital assistants (PDAs), cellular phones and computers, all of which are installed with navigator software which supports a global positioning system (GPS). The digital global positioning information comprises a geographic location message. The positioning signal processing module  100  is a global positioning system module (GPS module). The first signal conversion module  101  is a digital-to-analog converter (D/A converter). The second signal conversion module  102  is an analog-to-digital converter (A/D converter). The radio signal processing devices  11  correspond to the positioning signal processing devices  10  and output, by radio transmission, the analog global positioning information outputted by the first signal conversion module  101 . The radio signal processing devices  11  are radio communication devices which comprise a radio module each. 
     The positioning signal processing devices  10  have a global positioning function and each comprise a positioning signal processing module  100  for executing the global positioning function and receiving digital global positioning information sent by a satellite while executing the global positioning function, a first signal conversion module  101  for performing digital-to-analog conversion on the digital global positioning information and outputting analog global positioning information, and a second signal conversion module  102  for performing analog-to-digital conversion. In the preferred embodiment, the positioning signal processing devices  10  are selected from the group consisting of personal digital assistants (PDAs), cellular phones and computers, all of which are installed with navigator software which supports a global positioning system (GPS). The digital global positioning information comprises a geographic location message. The positioning signal processing module  100  is a global positioning system module (GPS module). The first signal conversion module  101  is a digital-to-analog converter (D/A converter). The second signal conversion module  102  is an analog-to-digital converter (A/D converter). The radio signal processing devices  11  correspond to the positioning signal processing devices  10  and output, by radio transmission, the analog global positioning information outputted by the first signal conversion module  101 . The radio signal processing devices  11  are radio communication devices which comprise a radio module each. 
     In this embodiment, with one of the corresponding radio signal processing devices  11 , one of the positioning signal processing devices  10  sends to the remaining ones of the positioning signal processing devices  10  the analog global positioning information outputted by the first signal conversion module  101 , allowing the second signal conversion module  102  of the remaining ones of the positioning signal processing devices  10  to perform the analog-to-digital conversion on the analog global positioning information and recover the digital global positioning information, thus enabling the positioning signal processing module  100  of the remaining ones of the positioning signal processing devices  10  to execute the global positioning function and display related information. 
     The configuration module  12  varies the quantity and/or an attribute, such as authority, of the positioning signal processing devices  10  when necessary. For instance, setting the default ones of the positioning signal processing devices  10  for receiving analog global positioning information outputted by all or part of the positioning signal processing devices  10 . 
     In order to apply the principle and enhance the performance of the present invention further, the positioning signal processing devices  10  of the present invention comprise a first cellular phone, a second cellular phone, a third cellular phone, the positioning signal processing module  100 , the first signal conversion module  101 , and the second signal conversion module  102 . The first, second and third cellular phones are each installed with navigator software which supports a global positioning system (GPS). The positioning signal processing module  100  is the global positioning system module (GPS module). The first signal conversion module  101  is the digital-to-analog converter (D/A converter). The second signal conversion module  102  is the digital-to-analog converter (A/D converter). The group global positioning system of the present invention is illustrated with a scenario where a group of three equipped with the first, second and third cellular phones carry out an expedition outdoors. First, the configuration module  12  configures and allows the first, second and third cellular phones to receive analog global positioning information from each other. Where the first cellular phone-carrying member falls behind for whatever reasons, with one of the corresponding radio signal processing devices  11 , the first cellular phone sends to the remaining ones of the positioning signal processing devices  10  (the second and third cellular phones) the analog global positioning information outputted by the first signal conversion module  101 , allowing the second signal conversion module of the remaining ones of the positioning signal processing devices  10  (the second and third cellular phones) to perform the analog-to-digital conversion on the analog global positioning information and recover the digital global positioning information, thus enabling the positioning signal processing module  102  of the remaining ones of the positioning signal processing devices  10  (the second and third cellular phones) to execute the global positioning function and display related information. 
     The second cellular phone-carrying member and the third cellular phone-carrying member are informed of the first cellular phone-carrying member&#39;s geographic location and thereby allowed to make a response, for example, proceeding, but more slowly than before, such that the first cellular phone-carrying member can catch up; meanwhile, the first, second and third cellular phone-carrying members may communicate with each other through the radio signal processing devices  11 . By the same token, the first cellular phone-carrying member is informed of the first and second cellular phone-carrying members&#39; geographic location, and thus the first cellular phone-carrying member may hurry to catch up. 
     In summary, a group global positioning system of the present invention comprise a plurality of positioning signal processing devices and a plurality of radio signal processing devices corresponding thereto. With one of the corresponding radio signal processing devices, one of the positioning signal processing devices outputs analog global positioning information to the remaining ones of the positioning signal processing devices, allowing the remaining ones of the positioning signal processing devices to perform analog-to-digital conversion on the analog global positioning information and recover digital global positioning information, thus enabling the remaining ones of the positioning signal processing devices to execute the global positioning function and display related information. Accordingly, with the group global positioning system of the present invention, a member of a group can be informed of her or his fellow members&#39; geographic locations such that a group activity is well-coordinated and well-controlled, thus preventing the group members from falling behind or getting lost. 
     The aforesaid embodiment merely serves as the preferred embodiment of the present invention. It should not be construed as to limit the scope of the present invention in any way. Hence, any other changes can actually be made in the present invention. It will be apparent to those skilled in the art that all equivalent modifications or changes made, without departing from the spirit and the technical concepts disclosed by the present invention, should fall within the scope of the appended claims.