Abstract:
A crosslinked positioning method sets one of the intercommunicated positioning devices as a master and the remaining ones as slaves through a crosslink allocation. The method includes the steps of searching several devices at the same time, receiving IDs and comparing the IDs. The device with a higher ID is a master, and the other devices with a lower ID are slaves. The master and slaves perform a data link through a search mode, a call mode, a frequency hopping mode, a transmission power adjusting mode or a correction time mode. After the data link is accomplished, positioning data of the master and the slaves are displayed simultaneously on a screen.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a global positioning system, and more particularly to a crosslinked positioning method for multiple users. 
     2. Description of Prior Art 
     Taking a trip or climbing a mountain has become one of the best leisure activities, and thus families, friends, and companies enjoy their getting together for outdoor activities during weekends or holidays. As economy and technology advance, cars are primarily used as a transportation means for outdoor activities, and multiple cars are usually teamed up to form a car team for the activity. 
     In general, when a car team sets off, each car of the team is equipped with a walkie-talkie or a mobile phone for communications to prevent any car from leaving behind or getting lost, or a satellite navigation system is provided for guiding the cars to the destination. Although walkie-talkies and mobile phones can be used for the coordination among cars, each driver has to watch the rear mirror from time to time and make sure that each car follows closely. If any car is left behind, the car in the front is informed to pull aside of the road and wait for the coming car, or notice the car left behind by walkie-talkies. However, such arrangement is very inconvenient, and may even cause an accident easily. Even though the car left behind can be guided to the destination by a satellite navigation system, the satellite navigation system used in a car usually allows users to locate their own position only, but not the positions of other cars or the distance of their car from others cars of the team. 
     In addition, disasters in mountain usually occur when a mountain climber gets lost in an unfamiliar mountain path or injured. For disasters in mountain, mountain climbers or victims are unable to inform rescuers immediately or tell the rescuers about their exact location, and they have to wait for rangers to find them after they have not returned at a specific time, and then the rescue team is informed. During a rescue, the rescuers have difficulties of locating the mountain climbers and victims who are in danger, and the rescuers have to search the whole mountain which may take lots of time and delay the time of rescuing the mountain climbers. 
     SUMMARY OF THE INVENTION 
     Therefore, it is a primary objective of the present invention to redesign the traditional positioning device, wherein several intercommunicated positioning devices of the same type are combined by a cross allocation, and one of the positioning devices is a master, and the remaining ones are slaves. During its application, both of the master and the slave can show their positions as well as the positions of others. In the meantime, the intercommunicated positioning device can transmit an emergency rescue signal to all users who hold the same kind of intercommunicated positioning devices to inform them about the signal transmitting position. 
     To achieve the foregoing objective, the present invention provides a crosslink communication positioning method for setting one of the intercommunicated positioning devices as a master and the remaining ones as slaves by a crosslink allocation. The method comprises the steps of searching a plurality of devices at the same time, searching a plurality of IDs, and comparing the IDs. The device with a large ID is the master, and the device with a small ID is a slave. The master and the slave perform a data link including a search mode, a call mode, a frequency hopping mode, a power transmission adjusting mode and a correction time mode. After the data link is completed, related positions and distance of the master and slaves are displayed simultaneously on a map displayed by the intercommunicated positioning device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic block diagram of an intercommunicated positioning device in accordance with the present invention; 
         FIG. 2  is a flow chart of entering each device into its respective allocated position in accordance with the present invention; 
         FIG. 3  is a continued flow chart of  FIG. 2 ; 
         FIG. 4(   a ) is a schematic view of a searching slave instruction packet data in accordance with the present invention; 
         FIG. 4(   b ) is a schematic view of a searching slave replay instruction packet data in accordance with the present invention; 
         FIG. 4(   c ) is a schematic view of a searching slave OK instruction packet data in accordance with the present invention; 
         FIGS. 5(   a ) and  5 ( b ) are flow charts of linking data of a master and a slave in accordance with the present invention; 
         FIG. 6(   a ) is a schematic view of a slave normal code packet data in accordance with the present invention; 
         FIG. 6(   b ) is a schematic view of a slave calling master packet data in accordance with the present invention; 
         FIG. 6(   c ) is a schematic view of a normal code master packet data in accordance with the present invention; 
         FIGS. 7(   a ) and  7 ( b ) are flow charts of performing a search by a master and a slave in accordance with the present invention; 
         FIGS. 8(   a ) and  8 ( b ) are flow charts of calling by a master and a slave in accordance with the present invention; 
         FIG. 9  is a schematic view of a slave calling master OK packet data in accordance with the present invention; 
         FIG. 10(   a ) and  10 ( b ) are flow charts of a frequency hopping mode in accordance with the present invention; 
         FIG. 11(   a ) is a schematic view of a channel and a slot frequency hopping packet data in accordance with the present invention; 
         FIG. 11(   b ) is a schematic view of a channel and a slot frequency hopping packet reply data in accordance with the present invention; 
         FIG. 11(   c ) is a schematic view of a channel and a slot frequency hopping OK packet data in accordance with the present invention; 
         FIGS. 12(   a ) and  12 ( b ) are flow charts of adjusting the transmission power of a slave in accordance with the present invention; 
         FIG. 13(   a ) is a schematic view of a slave PA adjust packet data in accordance with the present invention; 
         FIG. 13(   b ) is a schematic view of a slave PA adjust Response packet data in accordance with the present invention; 
         FIG. 13(   c ) is a schematic view of a slave PA adjust OK packet data in accordance with the present invention. 
         FIGS. 14(   a ) and  14 ( b ) are flow charts of making an emergency call by a master and a slave in accordance with the present invention; 
         FIG. 15  is a schematic view of an emergency call packet data in accordance with the present invention; 
         FIG. 16  is a flow chart of searching an emergency call in accordance with the present invention; 
         FIG. 17  is a flow chart of correcting time in accordance with the present invention; 
         FIGS. 18(   a ) and  18 ( b ) are flow charts of pairing two new devices in accordance with the present invention; 
         FIG. 19(   a ) is a schematic view of linking an instruction packet data in accordance with the present invention; 
         FIG. 19(   b ) is a schematic view of linking and replying an instruction packet data in accordance with the present invention; 
         FIG. 19(   c ) is a schematic view of linking an OK instruction packet data in accordance with the present invention; and 
         FIGS. 20(   a ) and  20 ( b ) are flow charts of pairing another two new devices in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The technical characteristics, features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings. The drawings are provided for reference and illustration only, but not intended for limiting the present invention. 
     Referring to  FIG. 1  for a schematic block diagram of an intercommunicated positioning device in accordance with the present invention, the intercommunicated positioning device comprises: a central processing unit (CPU)  1 , a wireless transceiver  2 , a global positioning system (GPS) circuit  3 , an electronic compass  4  and a display device  5 . 
     The CPU  1  is provided for controlling an external circuit and an internal operation, and executing an external instruction. The CPU is electrically coupled to a communication port  11 , for receiving a command and a response (such as pairing, linking, data report, and emergency call, etc) outputted by an external hardware. 
     The wireless transceiver  2  is electrically coupled to the CPU  1  for transmitting a signal outputted by the CPU  1  to another intercommunicated positioning device, or receiving a signal transmitted by another intercommunicated positioning device. 
     The GPS circuit  3  is electrically coupled to the CPU  1  for receiving a coordinate position signal into the CPU  1 . 
     The electronic compass  4  is electrically coupled to the CPU  1  for providing angle information of a geomagnetic north pole or a geomagnetic south pole of the device to the CPU  1 . 
     The display device  5  is electrically coupled to the CPU  1  and driven by the CPU  1  for displaying the linked information and the position information of several intercommunicated positioning devices. 
     The communication port is electrically coupled to the CPU  1  for receiving an external command of the CPU, an external signal from a satellite or a signal from the electronic compass. 
     The aforementioned intercommunicated positioning devices perform a many-to-may crosslink communication positioning allocation, and the circuits and programs of each intercommunicated positioning device are the same, and thus only one of the devices needs to be set as a master by the crosslink positioning communication method, and the remaining ones are slaves. 
     Referring to  FIGS. 2 and 3  for flow charts of entering each device into its allocated position, two devices are allocated and compared, and a first device with an ID  001  enters into Step  100 . 
     Step  102 : The first device enters into a device searching channel and issues a searching slave command. In the figures, the searching slave command packet data comprises: a data length, a device type, a device ID, a searching slave field, a slave ID, a master slot, a master data num, a GPS Fix or Not, a working channel, and a working slot as shown in  FIG. 4(   a ), and the packet format can vary with the requirements of different systems. 
     In the meantime, the second device with an ID  002  enters into Step  104 . 
     Step  106 : The second device enters into a device searching channel to issue a searching slave command. In the figures, the searching slave command packet data comprises: a data length, a device type, a device ID, a searching slave field, a slave ID, a master slot, a master data num, a GPS Fix or Not, a working channel and a working slot as shown in  FIG. 4(   a ), and the packet format can vary with the requirements of different systems. 
     Step  108 : Wait and see whether or not there is a slave response or a master searching. If there is no slave response or master searching, then return to Step  102 ; if there is a slave response or master searching, then go to Step  110  to receive a searching slave command from the second device, wherein the ID of the second device is greater than the ID of the first device, and thus the first device is a slave, and the second device is a master. 
     Step  112 : Set the first device to be a slave. 
     Step  114 : Set the second device to be a master. 
     Step  116 : The master is ready to receive the searching slave command of the slave. 
     Step  118 : The slave transmits the searching slave response command data to the master. In the figure, the searching slave response command packet data comprises: a data length, a device type, a device ID, a searching slave response field, a slave slot, a slave data num, and a GPS Fix or Not as shown in  FIG. 4(   b ), and the packet format can vary with the requirements of different systems. 
     Step  120 : Wait and see whether or not there is a searching slave command of the slave. If there is no searching slave command of the slave, then return to Step  116 . If there is a searching slave command data, then go to Step  122  to transmit a searching slave OK command to the slave. In the figure, the searching slave OK command packet data comprises: a data length, a device type, a device ID, a searching code, a slave ID, a master slot, a master data num, and a GPS Fix or Not as shown in  FIG. 4(   c ), and the packet format can vary with the requirements of different systems. 
     Step  124 : Wait and see whether or not there is a searching slave OK command. If there is a searching slave OK command, then go to Step  126 , and the next cycle will transmit the position according to the data of the searching slave command for a data link, and go to Step  128  for the data link. 
     Step  130 : Determine whether or not there is a paired but not linked device. If no, then return to Step  128 ; and if yes, then go to Step  132  for the master, and Step  134  for the slave. 
     After the master enters into Step  132 , go to Step  136 . If the master is not at a working slot, then jump to the device searching channel to issue a searching slave command to search a device, and then go to Step  140  to determine whether or not a searching slave command of a new device is received. If there is no searching slave command of a new device, then return to Step  136 . 
     If the slave enters into Step  138  and is not at a working slot, then the slave jumps to a device searching channel to monitor whether or not there is a new device, and then go to Step  140  to determine whether or not a searching slave command of a new device is received. 
     If a third device with an ID  003  enters into Step  142 , the device entering into the device searching channel issues a searching slave command data in Step  144 . 
     Go to Step  140  to determine whether or not a searching slave command from a new device is received. Go to Step  146 , and each device starts comparing the IDs, and the device with the largest ID is the master. Therefore, the first device is a slave (Step  148 ), and the second device is a slave (Step  150 ) and the third device is a master (Step  152 ). 
     If the third device is a master, then go to Step  154 , and prepare for receiving a searching slave response command data of the slave. 
     Go to Step  156  to determine whether or not a searching slave command of any slave is received. If no searching slave command of a slave is received, then return to Step  154 . If a searching slave command of a slave is received, then go to Step  158 , and issue a searching slave OK command to the slave. 
     Go to Step  160  to determine whether or not there is a non-linked device. If there is a non-linked device, then return to Step  144 . If there is a device to be linked, then go to Step  162 , and enter into the next cycle for a data link. 
     If the first device in Step  148  and the second device in Step  150  are slaves, then go to Step  164 . If all prepared items of the slave are ready, a searching slave response command is transmitted to the master within a cycle as shown in  FIG. 4(   b ), and the packet format can vary with the requirements of different systems. 
     Go to Step  166  to determine whether or not there is a searching slave OK command received by the master as shown in  FIG. 4(   c ), and the packet format can vary with the requirements of different systems. If no searching slave OK command is received by the master, then return to Step  164 . If a searching slave OK command is received by the master, then go to Step  168  and enter into the next cycle for a data link. 
     Referring to  FIGS. 5(   a ) and  5 ( b ) for flow charts of performing a data link of a master and a slave in accordance with the present invention, the master (or the third device) performs a data link to the slave as shown in Step  200 , and transmits a normal code slave data to the slave according to the slot produced by the master. Then, go to Step  202  to determine whether or not a normal code slave data is received. If no normal code slave data is received, then return to Step  200 . If a normal code slave data is received, then go to Step  204  to search for a device. In the figure, the normal code slave packet data comprises: a data length, a device type, a device ID, a normal code slave field, a longitude, latitude, a PA Level, a slave channel, slave slot, a slave data num, and a GPS Fix or Not as shown in  FIG. 6(   a ), and the packet format can vary with the requirements of different systems. 
     After Step  200 , go to Step  206  to determine whether or not a slave calling master data is received. If no slave calling master data is received, then return to Step  200 . If a slave calling master data is received, then go to Step  208  to enter into a call master mode. In the figure, the slave calling master packet data comprises: a data length, a device type, a device ID, a slave calling master field, a longitude, a latitude, a slave channel, a slave slot, a slave data num, a GPS Fix or Not as shown in  FIG. 6(   b ), and the packet format can vary with the requirements of different systems. 
     After Step  200 , go to Step  210  to determine whether or not a frequency hopping is required. If it is determined that no frequency hopping is required, then return to Step  200 . If it is determined that a frequency hopping is required, then go to Step  212  to enter into a frequency hopping mode. 
     After Step  200 , go to Step  214  to determine whether or not an adjustment of a transmission power of the slave is required. If no adjustment of the transmission power of the slave is required, then return to Step  200 . If an adjustment of the transmission power of the slave is required, then go to Step  216  to enter into a transmission power adjusting mode. 
     When the slave (first device and second device) performs a data link with another slave as shown in Step  300 , the master allocates the slot to transmit a normal code slave to the master. 
     Step  302  determines whether or not the device type is a master. If the device type is determined to be not a master, then go to Step  304 , wherein not only the data of the master is received, but the data of other slaves in the group is received as well. Then, go to Step  306  to determine whether or not all slaves have received the data. If it is determined that not all slaves have received the data, then return to the Step  304 . If it is determined that all slaves have received the data, then go to Step  308 , and wait for another new master at the device searching channel if the master is not at the working slot. 
     If the device in Step  302  is determined to be a master, then go to Step  310  and receive a normal code master packet data at the transmitting slot of the master as shown in  FIG. 6(   c ), and the packet format can vary with the requirements of different systems. 
     In Step  312 , determine whether or not a normal code master data of the master is received. If it is determined that no normal code master data is received, then return to Step  310 . If it is determined that a normal code master data is received, then perform the search of a device. 
     Referring to  FIGS. 7(   a ) and  7 ( b ) for flow charts of performing a search by a master and a slave in accordance with the present invention; a master performs a search in Step  400 , and enters into a search mode to search a paired but not linked slave. 
     Step  402 : Use a random number to produce a slot in a device searching channel. 
     Step  404 : Transmit a searching slave command as shown in  FIG. 4(   a ) to search a lost slave. 
     Step  406 : Determine whether or not there is a searching slave response command of the slave as shown in  FIG. 4(   b ), and the packet format can vary with the requirements of different systems. If there is no searching slave response command, then return to Step  404 ; if there is a searching slave response command, then go to Step  408  to transmit a searching slave OK command as shown in  FIG. 4(   c ) to the salve to complete the notice, and the packet format of the slave can vary according to the requirements of different systems. 
     Step  410 : Determine whether or not there is a non-linked slave. If there is a non-linked slave, then return to Step  404 ; and if there is no non-linked slave, then go to Step  412  to complete the search mode. 
     When the slave performs a search as shown in Step  500 , the search mode is entered, and a searching slave command of the master is received at the device searching channel. 
     Step  502 : Determine whether or not a searching slave command of the master is received. If it is determined that no searching slave command of the master is received, then return to Step  500 . If it is determined that a searching slave command of the master is received, then go to Step  504 . 
     Step  504 : Transmit a searching slave response command to the master to confirm the receipt of the searching slave command. 
     Step  506 : Determine whether or not a searching slave OK command of the master is received. If it is determined that no searching slave OK command of the master is received, then return to Step  504 . If it is determined that a searching slave OK command of the master is received, then go to Step  508  to complete the search mode. 
     Referring to  FIGS. 8(   a ) and  8 ( b ) for flow charts of calling by a master and a slave in accordance with the present invention, when a slave calls a master as shown in Step  600 , a slave calling master data is transmitted to the master. 
     Step  602 : Determine whether or not the calling continues. If the calling continues, then return to Step  602 . If the calling stops, then go to Step  604  to issue a slave calling master OK data to the master. Then, go to Step  606  to complete a slave call. In the figure, the slave calling master OK packet data comprises: a data length, a device type, a device ID, a slave calling master field, a slave channel, a slave slot, a slave data num, and a GPS Fix or Not as shown in  FIG. 9 , and the packet format can vary with the requirements of different systems. 
     As to the master as shown in Step  700 , a slave calling master data of the slave is received. 
     Step  702 : Calculate the relative distance and position between the master and the slave. 
     Step  704 : Determine whether or not a slave calling master OK data of the slave is received. If it is determined that no slave calling master OK data of the slave is received, then return to Step  700 . If it is determined that a slave calling master OK data of the slave is received, then go to Step  706  to complete the slave call. 
     Referring to  FIG. 10(   a ) and  10 ( b ) for flow charts of a frequency hopping mode in accordance with the present invention, the master as shown in Step  800  is at a frequency hopping mode, and when the intensity of a received signal is too weak, or the data loss in a same slot is too large, then enter into a frequency hopping mode. 
     Step  802 : Start searching all master transmitting slot channels to observe whether or not there are a channel and a master transmitting slot available. 
     Step  804 : Determine whether or not available channel and master transmitting slot are searched. If no channel and master transmitting slot are available, return to Step  802 . If it is determined that available channel and master transmitting slot are searched, then go to Step  806 . 
     Step  806 : Issue a channel and slot hopping data to notice all slaves for a frequency hopping. The channel and slot hopping packet data comprises: a data length, a device type, a device ID, a hopping code, a master channel, a master slot, a master data num, a next channel, a next slot, and a GPS Fix or Not as shown in  FIG. 11(   a ), and the packet format can vary with the requirements of different systems. 
     Step  808 : Determine whether or not the channel and slot hopping response data of all slaves are received. If it is determined that no channel and slot hopping response data of all slaves is received, then return to Step  806 . If it is determined that the channel and slot hopping response data of a slave is received, then go to Step  810 . In the figure, the channel and slot hopping response packet data comprises: a data length, a device type, a device ID, a channel and slot hopping response field, a slave channel, a slave slot, a slave data num, a GPS Fix or Not as shown in  FIG. 11(   b ), and the packet format can vary with the requirements of different systems. 
     Step  810 : Issue a channel and slot hopping OK data to notice all slaves to start the frequency hopping. In the figure, the channel and slot hopping OK packet data comprises: a data length, a device type, a device ID, a channel and slot hopping OK field, a master channel, a master slot, a master data num, and a GPS Fix or Not as shown in  FIG. 11(   c ), and the packet format can vary with the requirements of different systems. 
     As to the slave as shown in Step  900 , the frequency and slot of the frequency hopping required for the channel and slot hopping response issued by the master is received. 
     Step  902 : Transmit the channel and slot hopping response of the received frequency hopping. 
     Step  904 : Determine whether or not a channel and slot hopping OK issued by the master is received. If it is determined that no channel and slot hopping OK issued by the master is received, then return to Step  902 . If it is determined that a channel and slot hopping OK issued by the master is received, then go to Step  906 , and start the frequency hopping at the next cycle. 
     Referring to  FIGS. 12(   a ) and  12 ( b ) for flow charts of adjusting the transmission power of a slave in accordance with the present invention, the master as shown in Step  1000  receives a data of the slave. 
     Step  1020 : Calculate the values of longitude and latitude and receive the intensity of a signal. 
     Step  1040 : Determine whether or not it is necessary to adjust the transmission power of the slave. If it is determined that no adjustment to the transmission power of the slave is required, return to Step  1020 . If it is determined that an adjustment to the transmission power of the slave is required, then go to Step  1060  to issue a slave PA adjust data to notice the slave to adjust the transmission power. In the figure, the slave PA adjust packet data comprises: data length, device type, device ID, PA Adjust, master channel, master slot, master data num, slave ID, PA Level, GPS Fix or Not, as shown in  FIG. 13(   a ), the packet format can vary with the requirements of different systems. 
     Step  1080 : Determine whether or not it is necessary to adjust the received slave PA adjust response data. If it is determined that an adjustment is required, return to Step  1060 . If it is determined that no adjustment is required, then go to Step  1100 . In the figure, the slave PA adjust response packet data comprises: a data length, a device type, a device ID, a PA Adjust, a slave PA adjust response field, a master channel, a master slot, a master data num, and a GPS Fix or Not as shown in  FIG. 13(   b ), and the packet format can vary with the requirements of different systems. 
     Step  1100 : Transmit a slave PA adjust OK packet data to notice the slave to complete an adjustment. The slave PA adjust OK packet data comprises: a data length, a device type, a device ID, a PA adjust, a slave PA adjust OK field, a master channel, a master slot, a master data num, a slave ID and a GPS Fix or Not as shown in  FIG. 13(   c ), and the packet format can vary with the requirements of different systems. 
     The slave as shown in Step  2000  receives a slave PA adjust of the master. 
     Step  2020 : Adjust the transmission power of the slave according to the slave PA adjust. 
     Step  2040 : Issue a slave PA adjust response to the master. 
     Step  2060 : Determine whether or not a slave PA adjust or a slave PA adjust OK is received. If it is determined that a slave PA adjust is received, return to Step  2000 . If it is determined that a slave PA adjust OK is received, then go to Step  2080  to adjust the received slave PA adjust. 
     Referring to  FIGS. 14(   a ) and  14 ( b ) for flow charts of making an emergency call by a master and a slave in accordance with the present invention, the master emergency call as shown in Step  3000  enters into the emergency call mode to disable all using functions. 
     Step  3020 : the transmitted emergency call (SOS) is adjusted at the emergency channel according to the remaining power of the battery. The emergency call (SOS) packet data comprises: a data length, a longitude, latitude and a device ID as shown in  FIG. 15 , and the packet format can vary with the requirements of different systems. 
     Step  3040 : Determine whether or not the emergency call mode is disabled. If it is determined that emergency call mode is enabled, then return to Step  3020 . If it is determined that emergency call mode is disabled, then go to Step  3060  to complete the emergency call mode and enable all functions. 
     The slave emergency call as shown in Step  4000  enters into the emergency call mode, and all using functions are disabled. 
     Step  4020 : Adjust the transmitted emergency call (SOS) at the emergency channel according to the remaining power of the battery. 
     Step  4040 : Determine whether or not the emergency call mode is disabled. If it is determined that emergency call mode is enabled, then return to Step  4020 . If it is determined that the emergency call mode is disabled, then go to Step  4060  to complete the emergency call mode and enable all functions. 
     Referring to  FIG. 16  for a flow chart of searching an emergency call in accordance with the present invention, the master is operated at a normal mode, and an emergency call signal is searched. If the master is turned on as shown in Step  5000 , a searching emergency call mode is entered. If the master is not at the slot of a working mode, the signal is received at the emergency call channel. 
     Step  5020 : Determine whether or not an emergency call (SOS) is received. If it is determined that no emergency call (SOS) signal is received, then return to Step  5020 . If it is determined that an emergency call (SOS) is received, then go to Step  5040  to receive the emergency call (SOS) to locate the longitude and latitude of the transmitting end, and calculate the position of the transmitting end. 
     Referring to  FIG. 17  for a flow chart of correcting time in accordance with the present invention, the master operated at a normal mode constantly issues a normal code to the slave, so that the slave knows about the existence of the master and both slave and master can check the time. 
     Therefore, if the master operated at a normal mode as shown in Step  6000  receives no other commands, the master will issue the normal code master to the slave at the slot of the master. 
     If the slave operated at the normal mode as shown in Step  7000  receives no other command, the slave will issue a normal code slave to the master at the slot of the slave. 
     Referring to  FIGS. 18(   a ) and  18 ( b ) for flow charts of pairing two new devices in accordance with the present invention, the master as shown in Step  8000  uses a random number to produce a slot at a bind channel. 
     Step  8020 : Receive a binding command packet data according to the slot transmission binding command, and the binding command packet data comprises: a data length, a device type, a device ID, a binding field, a master slot, a master data num, a working channel, a working slot, and a GPS Fix or Not as shown in  FIG. 19(   a ), the packet format can vary with the requirements of different systems. 
     Step  8040 : Determine whether or not a binding response command of the slave is received. If it is determined that no binding response command of the slave is received, return to Step  8020 . If it is determined that a binding response command of the slave is received, then go to Step  8060 . In the figure, the binding response command packet data comprises: a data length, a device type, a device ID, a binding response field, a slave slot, a slave data num and a GPS Fix or Not as shown in  FIG. 19(   b ), and the packet format can vary with the requirements of different systems. 
     Step  8060 : Transmit a binding OK command after the binding response command from the slave is received. The binding OK command packet data comprises: a data length, a device type, a device ID, a binding OK field, a master slot, a master data num and a GPS Fix or Not as shown in  FIG. 19(   c ), and the packet format can vary with the requirements of different systems. 
     The slave as shown in Step  9000  enters into a bind channel and gets ready to receive a binding command of the master. 
     Step  9020 : Determine whether or not a binding command of the master is received. If it is determined that no binding command of the master is received, return to Step  9000 . If it is determined that a binding command of the master is received, then go to Step  9040  to transmit a binding response command to the master after the binding command of the master is received. 
     Step  9060 : Determine whether or not a binding OK command of the master is received. If it is determined that no binding OK command of the master is received, return to Step  9040 . If it is determined that a binding OK command of the master is received, then go to Step  9080  to complete pairing after the binding OK command of the master is received. 
     Referring to  FIGS. 20(   a ) and  20 ( b ) for flow charts of pairing another two new devices in accordance with the present invention, a first master as shown in Step  10000  uses a random number to produce a slot at a bind channel. 
     Step  10020 : Receive at other slot according to the produced slot transmission binding command. 
     Step  10040 : Determine whether or not a binding command of a second master is received. If it is determined that no binding command of the second master is received, return to Step  10020 . If it is determined that binding command of the second master is received, then go to Step  10060  to compare the ID, and the ID of the first master is larger, and thus the second master serves as a slave. 
     Step  10080 : Determine whether or not the first master has received a binding response command of the second master. If it is determined that no binding response command of the second master is received, return to Step  10020 . If it is determined that a binding response command of the second master is received, then go to Step  10100 . 
     Step  10100 : Transmit a binding OK command to the second master after the binding response command from the second master is received. 
     The second master as shown in Step  20000  uses a random number to produce a slot at a bind channel. 
     Step  20020 : Receive at other slot according to the slot transmission binding command. 
     Step  20040 : Determine whether or not a binding command of a first master is received. If it is determined that no binding command of a first master is received, return to Step  20020 . If it is determined that a binding command of a first master is received, then go to Step  20060  to compare the IDs, and the ID of the first master is larger, and thus the second master serves as a slave. 
     Step  20080 : Transmit a binding response command. 
     Step  20100 : Determine whether or not a binding OK command of the master is received. If it is determined that no binding OK command of the master is received, return to Step  20080 . If it is determined that a binding OK command of the master is received, then go to Step  20120  to end pairing after the binding OK command of the first master is received. 
     After the foregoing allocation is completed, several intercommunicated positioning devices can be allocated such that one device serves as the master, and the remaining devices serves as the slaves in a communication positioning mode, and such devices can be applied to calls or emergency calls (mountain climbing rescues) for a group (such as a car team or a mountain climbing team). 
     While the invention is described in by way of example and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, the aim is to cover all modifications, alternatives and equivalents falling within the spirit and scope of the invention as defined by the appended claims.