Abstract:
Disclosed is a positioning system using sound waves. The system provides the current location of a user carrying a dedicated terminal or any portable equipment possessing a microphone and a speaker in real time by using sound waves propagating in slow speed in various indoor spaces such as shopping malls, museums, and art galleries where GPS signals are not received.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to a system for providing location information using sound waves. The present invention, in particular, relates to a positioning system using sound waves, capable of providing the current location of a user in real time by using sound waves travelling in slower speed than radio waves in various indoor spaces such as department stores, shopping malls, museums, and art galleries. 
         [0003]    2. Background 
         [0004]    In general, positioning systems to provide location-based services (LBS) may be classified into a network-based scheme using RF signal information of cellular stations over a mobile communication network and a GPS type positioning scheme using a GPS receiver. 
         [0005]    The above schemes may be suitable for outdoor spaces that have a superior environment to receive radio waves, but they are not suitable for shadow areas of satellite signals such as indoor spaces. In addition, the above schemes may require highly priced transmitter-receivers and highly priced relaying devices. Furthermore, high-energy radio waves can be harmful to human body. 
         [0006]    Accordingly, various references including Korea Unexamined Patent Publication No. 2005-95401 have suggested various devices capable of detecting the location of a 3-D space by using the transmission time of sound waves. In other words, the distance (S=V×T) is obtained by recording the time, when the sound wave is generated, and time spent until the sound wave reaches a destination, and the location is detected through a triangulation scheme. 
         [0007]    However, the applicability of the conventional location determination technologies using sound waves may not be useful since they are used to simply detect a 3-D space itself. 
         [0008]    Since GPS signals do not reach various indoor spaces such as department stores, shopping malls, museums, and art galleries, it&#39;s not easy to provide information of a facility or an object based on user&#39;s location information or to offer convenient navigation, route suggestions, and search facility functions. 
         [0009]    As shown in the case of using the strength of radio wave signals generated from radio wave signaling devices nearby, positioning systems using radio wave signals can produce a great margin of error and can be affected by many variables, which may not be practically useful in many cases. 
       BRIEF SUMMARY OF THE INVENTION 
     Technical Problems 
       [0010]    The present invention has been presented to solve the technical problems in the related art; and it is the object of the present invention to provide a positioning system using sound waves, capable of determining the current location of a user in real time by using sound waves travelling in slow speed in various indoor spaces such as department stores, shopping malls, museums, and art galleries. 
         [0011]    In addition, the present invention provides a positioning system using sound waves, capable of providing various applications by indicating the current location of a user through a portable terminal, a map in which the floor plan of a building is displayed, and additional information of facilities or contents corresponding to each items on the map. 
       Solutions 
       [0012]    To this end, a positioning system using sound waves according to the present invention is proposed. The system includes a plurality of node signal generators installed at fixed locations in an indoor space, respectively, to transmit sound waves in non-audible frequency bands that carries an identification number, absolute location information, relative location information, and time of signal generation of the node signal generators, and a portable terminal to receive the sound waves transmitted from the node signal generators, to calculate distances from the node signal generators by using a difference between the time of signal generation and the time of signal reception, to calculate the current location of the portable terminal by combining the calculated distances and the absolute location information, and to display the current location of the portable terminal on a display unit. 
         [0013]    Preferably, each node signal generator includes a node memory to record the identification number, the absolute location information of the node signal generator, a node timer to provide the time of signal generation, a node sound wave generator to generate the non-audible sound wave that include an identification number and the absolute location information provided from the node memory, and the time of signal generation provided from the node timer, and a node speaker to transmit the sound wave generated from the node sound wave generator. 
         [0014]    In addition, the node signal generator receives sound wave signals, which carries an identification number of the portable terminal and a signal generation time from the portable terminal and transmits the information to a management server along with the time at which the sound wave is received, and the management server calculates the current location of the portable terminal by using the identification number of the portable terminal, the time of signal generation, and the time at which the sound wave is received by the node signal generator. 
         [0015]    In addition, the portable terminal includes a terminal microphone to receive the sound wave transmitted from the node signal generator, a terminal location calculation unit comprising a distance calculator, which calculates the distance from the node signal generator by using the difference between the time of signal generation received through the terminal microphone and the time of signal reception, and a location calculator which calculates the current location of the portable terminal by combining the calculated distance and the absolute location information, a terminal timer to provide the current time, when the sound wave is received, to the distance calculator of the terminal location calculation unit, a terminal memory to record therein a map representing a structure of the indoor space, and a display unit to map information of the current location of the portable terminal, which is provided by the terminal location calculation unit, on the map provided in the terminal memory, and display the map. 
         [0016]    The system further includes a management server to record information of the current location of the portable terminal received from the node signal generator or the portable terminal. 
         [0017]    The management server also provides a map representing a floor structure to the portable terminal. 
         [0018]    In addition, the management server provides the descriptions of facilities in each section on the map or the descriptions of contents on the map to the portable terminal along with the map, and the portable terminal displays the map, the description, and the current location to the user. 
       Advantages of the Invention 
       [0019]    As described above, according to the positioning system using the sound wave, the current location of a user can be informed in real time by using sound waves propagating at a slower velocity in various indoor spaces such department stores, shopping malls, museums, and art galleries. 
         [0020]    In addition, various applications can be provided by indicating the current location of a user through a portable terminal, a map in which the floor plan of a building is displayed, and additional information of facilities or contents corresponding to each items on the map. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a view showing a map provided in the positioning system using sound waves according to the present invention. 
           [0022]      FIG. 2  is a view showing a scheme of calculating the location in the positioning system using sound waves according to the present invention. 
           [0023]      FIG. 3  is a view showing the structure of the positioning system using sound waves according to the present invention. 
           [0024]      FIG. 4  is a block diagram showing the structure of a node signal generator in the positioning system using sound waves according to the present invention. 
           [0025]      FIG. 5  is a block diagram showing the structure of a portable terminal in the positioning system using the sound waves according to the present invention. 
           [0026]      FIG. 6  is a block diagram showing the structure of a management server in the positioning system using sound waves according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Hereinafter, a positioning system using sound waves according to an exemplary embodiment of the present invention will be described in detail with reference to accompanying drawings. 
         [0028]    In the following description, the term “indoor spaces” refers to various places such as department stores, shopping malls, museums, art galleries, and theaters. 
         [0029]    As shown in  FIG. 1 , according to the present invention, node signal generators  10  are installed in fixed locations of indoor spaces. In addition, as shown in  FIG. 2 , a portable terminal  20 , which is carried by a user, calculates the current location of the portable terminal  20  and informs the user of the current location thereof. 
         [0030]    The portable terminal  20  can be a positioning terminal, which is especially manufactured for the application of the present invention, or a portable communication device such as a smart phone or a tablet PC carried by the user. 
         [0031]    In the case of the smart phone or the tablet PC, the present invention may be applied by installing an additional application, and a microphone and a speaker embedded in the smart phone or the tablet PC may be utilized. The sound wave signals can be recognized with the typical portable communication devices accordingly. 
         [0032]    To this end, the node signal generator  10  radiates a sound wave in non-audible frequencies, and the portable terminal  20  calculates the distance (s=v×t) between the node signal generator  10  and the portable terminal  20  by using the time (t) taken for the radiated sound wave to travel and the velocity (v) of the sound wave. 
         [0033]    In addition, the current location of the portable terminal  20  is calculated based on the absolute location information of the node signal generator  10  and the distance (s) between the portable terminal  20  and the node signal generator  10  and provided. The current location of the portable terminal  20  is calculated through a triangulation scheme generally known to those skilled in the art, and the current location calculated is marked on the map m representing the internal structure of a museum and the like. 
         [0034]    For example, when the user moves and positions at a specific location as shown in  FIG. 2 , distances S 1  to S 5  from five node signal generators  10   b,    10   c,    10   d,    10   e,  and  10   h  close to the portable terminal  20  among several node signal generators  10   a  to  10   i  are calculated, and the current location of the portable terminal  20  is marked on the map. 
         [0035]    As shown in  FIG. 3 , the present invention provides the node signal generators  10  installed in fix locations to radiate sound waves and the portable terminal  20  to receive the sound wave radiated from the node signal generator  10  and calculate and display the current location of the portable terminal  20  so that the location information can be displayed. In addition, as needed, the present invention may additionally provide a management server  30 . 
         [0036]    The node signal generator  10  basically includes a node speaker  14  to radiate the sound wave to the portable terminal  20 . In addition, the node signal generator  10  includes a node microphone  15  as described below to receive sound signals from the portable terminal  20 . 
         [0037]    The portable terminal  20  can be leased, for example, in a museum, and includes a terminal microphone  21  to receive sound waves from the node signal generator  10 . The portable terminal  20  carries a display unit  25  to display a map m corresponding to the internal structure. On the map m, a current location  20 ′ of the portable terminal  20  is marked (in the shape of a star). In addition, the portable terminal  20  carries a terminal speaker  27  behind as described below to radiate a sound signal to the node signal generator  10 . 
         [0038]    The management server  30  (see  FIG. 6 ) traces and records the movement path of the portable terminal  20 , and provides various kinds of services including the information of the map m to the portable terminal  20 . Although not shown in  FIG. 3 , management servers  30  are installed in various kinds of places including a management office. 
         [0039]    In more detail, each node signal generator  10  is installed at fixed locations of the indoor space to radiate a sound wave contains an identification number (ID_node), absolute location information, relative location information, and a signal generation time of the node signal generator. 
         [0040]    Since a plurality of node signal generators  10  are provided, the node signal generator  10  have their own identification numbers (ID_node) so that the node signal generators  10  are distinguished from each other. The absolute location information includes the latitude, the longitude, and the altitude of a location in which each node signal generator  10  is installed. The signal generation time refers to a time when the sound wave is generated. 
         [0041]    The latitude, the longitude, and the altitude used for the absolute location information is to enable a device to seamlessly work with other positioning systems such as global positioning system (GPS) when a user moves in and out of indoor spaces. 
         [0042]    As shown in  FIG. 4 , the node signal generator  10  includes a node memory  11 , a node timer  12 , a node sound wave generator  13 , a node speaker  14 , a node microphone  15 , a node wireless/wire communication unit  16 , and a node controller  17 . 
         [0043]    The node memory  11  stores the identification number, the absolute location information, and the signal generation time that are described above. In addition, the node memory  11  may contain various application programs for the processing the node signal generator  10 . 
         [0044]    The node timer  12  is functions like a clock, and provides current time to the node controller  17 , so that the node controller  17  can recognize the time of the sound wave generation. 
         [0045]    The node sound wave generator  13  generates a non-audible sound wave and contains the identification number and the absolute location information provided from the node memory  11 , and the signal generation time provided from the node timer  12 . 
         [0046]    The non-audible sound wave is used to prevent users in the indoor spaces from hearing the sound wave. The sound wave contains the various pieces of information including the identification number, which are obtained through various signal processing schemes and various signal modulation schemes. 
         [0047]    The node speaker  14  radiates a sound wave generated from the node sound wave generator  13 . Since the sound wave may be transmitted through an antenna or an ultra-sonic oscillator in addition to the speaker, an antenna or an ultra-sonic oscillator can also be used instead of the node speaker  14 . 
         [0048]    The node microphone  15  and the node wireless/wired communication unit  16  are added according to the need. The node microphone  15  receives the sound waves radiated from the portable terminal  20 . The node wireless/wired communication unit  16  transmits the received sound waves to the management server  30 . 
         [0049]    In other words, the portable terminal  20  radiates a sound wave, which includes an identification number (ID_terminal) of the portable terminal  20  and a signal generation time (t_t), to the node signal generator  10 . The node signal generator  10  adds a time (t_n), at which the sound wave is received, to the received sound wave and transmits the received sound wave having the time (t_n) to the management server  30 . 
         [0050]    Accordingly, separately from the case that the portable terminal  20  measures and provides the current location of a user, the management server  30  may also calculate current locations of the portable terminal  20  and manage the calculated current locations together. 
         [0051]    Meanwhile, the node controller  17  controls the overall processes of the node signal generator  10  including the node memory  11 , the node timer  12 , the node sound wave generator  13 , and the node wireless/wired communication unit  16 . 
         [0052]    The portable terminal  20  receives sound waves radiated from a plurality of node signal generators  10  and calculates the distances from the node signal generators  10  by using the differences between signal generation times and signal reception times. The portable terminal  20  calculates the current location thereof by combining the calculated distances and the absolute location information, and displays the calculated current location thereof on the display unit  25 . As shown in  FIG. 5 , the portable terminal  20  includes a terminal microphone  21 , a filter unit  21   a,  a terminal location calculation unit  22 , a terminal timer  23 , a terminal memory  24 , a display unit  25 , a terminal sound wave generator  26 , a terminal speaker  27 , a terminal wireless communication unit  28  and a terminal controller  29 . 
         [0053]    The terminal microphone  21  receives the sound wave radiated from the node signal generator  10 . However, different kinds of sound wave receptors may be used instead of the terminal microphone  21 . 
         [0054]    The filter unit  21   a  filters sound waves received through the terminal microphone  21  to remove noises. A low noise amplifier (LNA), for example, may be used for the filter unit  21   a.    
         [0055]    The terminal location calculation unit  22  can calculate the current location of the portable terminal  20 . For example, the terminal location calculation unit  22  carries a distance calculator  22   a  to calculate a distance and a location calculator  22   b  to calculate the current location based on the calculated distance. 
         [0056]    The distance calculator  22   a  calculates the distance (s=v×t) between the node signal generator  10  and the portable terminal  20  by using the difference (t=t 2 −t 1 ) between the signal generation time (t 1 ) (i.e., time at which a sound wave is radiated from the node signal generator  10 ) contained in the sound wave and the signal reception time (t 2 ) (i.e., time at which the sound wave is received in the portable terminal  20 ). 
         [0057]    The location calculator  22   b  calculates the current location of the portable terminal  20  by combining calculated distances and the absolute location information. The location calculator  22   b  generally calculates distances from three close node signal generators  10 , and takes into consideration the absolute location information along with the calculated distances to calculate the current location of the portable terminal  20  through generally-known triangulation schemes. 
         [0058]    The current location of the portable terminal  20  in the indoor spaces may be determined by the terminal location calculation unit  22  that includes the distance calculator  22   a  and the location calculator  22   b.  The calculated current location of the portable terminal  20  is displayed on the display unit  250  as described below and notified to the user of the portable terminal  200 . 
         [0059]    The terminal timer  23  provides, the time when the sound wave is received, to the distance calculator  22   a  of the terminal location calculation unit  22 , thereby calculating the distance between the node signal generator  10  and the portable terminal  20  as described above. 
         [0060]    The terminal memory  24  basically records therein the map m showing the structure of the indoor space and the current location. Since the map m usually has the form of an image file, the map m is displayed on the display unit  25  through a predetermined signal processing scheme. In this case, the current location of the portable terminal  20  is mapped on the map m so that the current location (see  20 ′ of  FIG. 3 ) of the portable terminal  20  is displayed. 
         [0061]    Various pieces of information corresponding to the map m are stored in the terminal memory  24 . The various pieces of information include information of various facilities such as exits, parking lots, and facilities, and various contents that may include descriptions of objects or exhibits. The map m and the information are displayed on the display unit  25 , so that various services can be provided to the user. 
         [0062]    The display unit  25  may include an LCD panel. A touch screen may be installed in the display unit  25  for the convenience in use. The display unit  25  displays the map m representing the structure of the indoor space and various pieces of information. If the display unit  25  includes a touch screen, the user can touch a specific area to obtain the information needed. 
         [0063]    The terminal sound wave generator  26  and the terminal speaker  27  are used to finally record the current location of the portable terminal  20  in the management server  30 . 
         [0064]    In other words, the terminal sound wave generator  26  generates a non-audible sound wave that include the identification number (ID_terminal) and the signal generation time (t_t) of the portable terminal  20 . The terminal speaker  27  radiates the sound wave generated from the terminal sound wave generator  26 . 
         [0065]    The sound wave radiated from the portable terminal  20  is received by the node microphone  15 , and the node signal generator  10  adds the time (t_n), when the sound wave is received, to the sound wave and transmits the sound wave that contains the time (t_n) to the management server  30  through the node wireless/wired communication unit  16 . The management server  30  calculates the current location of the portable terminal  20  by using the sound wave that contains the time (t_n). 
         [0066]    However, the portable terminal  20  may employ a scheme of directly transmitting information, which is subject to data signal processing, instead of the sound wave. In this case, a terminal wireless communication unit  28  can be used. 
         [0067]    The management server  30  may receive information of the current location of the portable terminal  20  directly from the portable terminal  20  or through the node signal generator  10  in order to acquire the information of the current location of the portable terminal  20 , and may employ any one of the above schemes. 
         [0068]    In addition, the management server  30  may directly receive the current location calculated by the terminal location calculator  22  of the portable terminal  20 , and may receive basic information used to calculate the location of the portable terminal  20  as well as the information of the identification number of the portable terminal  20 , the sound wave generation signal, and the sound wave arrival signal. 
         [0069]    The terminal wireless communication unit  28  is used for various communication purposes such as and not limited to reception of synchronization signal or node signaler information or the map m from the management server  30  or the transmission of current location data from or to the management server  30 . The terminal controller  29  controls the overall processes of the related portable terminal  20 . 
         [0070]    The management server  30  to record the current location information of the portable terminal  20  is provided additionally. 
         [0071]    As shown in  FIG. 6 , the management server  30  includes a location information database (DB)  31 , a map DB  32 , content DB  33 , a wired/wireless communication unit  34 , a server location calculator  35 , and a CPU  36 . 
         [0072]    The location information DB  31  records therein the identification number and the current location of the portable terminal  200 , which is carried by each user, minute by minute. Accordingly, the movement paths of several users can be observed. 
         [0073]    The location information DB  31  may be used in various services such as a service of searching for missing children through using the current location of the portable terminal  20 . 
         [0074]    The map DB  32  stores the map m corresponding to the structure of the indoor space managed by the related management server  30 . The map m stored in the map DB  32  is transmitted to the portable terminal  20  located in a remote place through the server wired/wireless communication unit  34 . The map DB  32  stores the location and the identification number of the node signal generators  100  in the indoor space. 
         [0075]    The content DB  33  stores information (or description) of various facilities or contents corresponding to locations on the map m, respectively, and then provides the information to the portable terminal  20  along with the map m. 
         [0076]    The server location calculator  35  receives the identification number of the portable terminal  20  and the sound wave generation time from the node signal generator  10 , and the sound wave reception time and the identification number of the node signal generator  10 , so that the management server  30  calculates the current location of the portable terminal  20 . 
         [0077]    The CPU  36  controls the overall operations of the components of the management server  30  described above. 
         [0078]    Although the system for providing location information according to the present invention has been described for illustrative purposes, those who are skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.