Abstract:
A communication device for use in a system including a first global positioning system satellite, a second global positioning satellite, a broadcast transmitter and a database. The communication device includes a first receiver, a processing portion, a transmission portion, a second receiver portion and a communication portion. The first receiver portion is operable to receive the broadcast signal. The processing portion is operable to extract the broadcast transmitter identification information from the broadcast signal. The transmission portion is operable to transmit the broadcast transmitter identification information to the database. The second receiver portion is operable to receive the correlation signal. The communication portion is operable to transmit a communication signal to the one of the first global positioning system satellite and the second global positioning satellite, based on the correlation signal.

Description:
The present application claims benefit under 35 U.S.C, §119 (e) to U.S. provisional patent application No. 61/141,790, filed Dec. 31, 2008, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     A mobile phone (also known as a wireless phone, cell phone, or cellular phone) is a communication device used for mobile voice or data communication over a cellular network of specialized base stations known as cell tower stations or cell towers. In addition to the standard voice function of a mobile phone, current mobile phones may support many additional services. One of these popular services is global positioning system (GPS) assistance. 
     A conventional method of obtaining accurate GPS assistance includes using a mobile phone to identify its current cell and to pass that data to a network server. The network server accesses a database that correlates a carrier cell&#39;s identification information to a geographic location. By then referencing a real-time GPS satellite database, a computer program may immediately discern which satellites are most visible to that mobile phone&#39;s cell. The orbits for these satellites, which are complied into a file called an ephemeris, are located and transmitted to the mobile phone. The mobile phone can then easily lock to the satellite network, as described in more detail below. 
       FIG. 1  illustrates a conventional satellite communication system used for a satellite GPS application. In the figure, satellite  104 , satellite  106  and satellite  108  are in orbits around Earth  102  in orbit  110 , orbit  112  and orbit  114 , respectively. The distance from any specific location on Earth  102  to each of satellite  104 , satellite  106  and satellite  108  varies with time. 
       FIG. 2  illustrates a satellite PGS application used in a conventional communication system. In the figure, a user  202 , is operating a mobile phone  204 , within range of a cell tower  206 . Further, satellites  104  and  106  are orbiting above Earth  102 . Mobile phone  204  is operable to communicate with cell tower  206 , as indicated by dashed communication line  208 , and to communicate with satellite  104 , as indicated by dotted communication line  210 . 
     A cellular network connects cell phones to one another via cell towers and satellites. Each cell tower communicates with one or more satellites, for example, cell tower  206  communicates with satellites  104  and  106  as indicated by dotted communication lines  212  and  214 , respectively. The satellites additionally are able to communicate with one another, for example, satellite  104  and  106  communicate with each other as indicated by dotted communication line  216 . Orbiting around Earth, each satellite is able to communicate to the cellular network by communicating with a plurality of cell towers. 
       FIG. 3  geographically illustrates a conventional cellular network. In the figure, region  302  is populated by multiple cells, a portion of which are illustrated as cells  304  through  348  (evenly numbered). Each cell is served by a fixed transmitter from one or more cell towers. A mobile phone user, within a cell, communicates via a cell tower geographically located within that cell For example, with additional reference to  FIG. 2 , if user  202  were located at point  350 , which is within cell  328 , then user  202  would communicate with others via cell tower  206  within cell  328 . 
     Referring back to  FIG. 2 , when user  202  wants to obtain GPS assistance, via mobile phone  204 , mobile phone  204  needs to communicate with a satellite within a GPS network. However, as discussed above, a plurality of satellites  104 ,  106  and  108  are constantly orbiting about Earth. As such, it may be difficult for mobile phone  204  to locate and lock onto a particular satellite. 
     A conventional method of addressing the problem of locating and locking onto a particular satellite, includes using the cellular network. Specifically, mobile phone  204  is used to communicate with cell tower  206 . Cell tower  206  recognizes its current cell identification information, for example the identification information of cell  328  in  FIG. 3 . Conventional databases list geographical location of cell towers, which includes cell tower  206 . Further, some conventional GPS service providers correlate the geographical location of cell towers to the plurality of GPS satellites through an ephemeris database. 
     Cell tower  206  is able to contact any one of many cell phone service providers having information that corresponds to the geographical location of cell tower  206 . The cell phone service provider may then references GPS service provider to obtain a real-time GPS satellite ephemeris that determines the closest orbiting satellite to cell tower  206 . As mobile phone  204  is within the transmission area of cell tower  206 , then the closest orbiting satellite to cell tower  206  is likely the closest orbiting satellite to mobile phone  204 . 
     Once the closest orbiting satellite to mobile phone  204  is identified, the GPS service provider provides communication data to the cell phone service provider, which then provides the communication data to mobile phone  204  via cell tower  206  to enable mobile phone  204  to locate and lock onto the satellite. In the example illustrated in  FIG. 2 , satellite  104  is closer than satellite  106  to cell tower  206 . This enables mobile phone  204  to communicate with satellite  104  as indicated by dotted communication line  210 . 
     The conventional approach of accessing a GPS service discussed above is not easy to implement because the region covered by each cell tower is limited. In addition, cell phone providers are required to pay royalties to utilize this technique. 
     What is needed is a system and method to lock to a GPS satellite without using the location data of a cell tower within a cellular communication system. 
     BRIEF SUMMARY 
     It is an object of the present invention to provide a system and method to lock to a GPS satellite without using the cellular communication system. 
     In accordance with an aspect of the present invention, a mobile phone may be used in a system including a first global positioning system satellite, a second global positioning satellite, a broadcast transmitter and a database. The first global positioning system satellite is operable to generate a first position signal. The second global positioning system satellite is operable to generate a second position signal. The broadcast transmitter is disposed in a first location and is operable to transmit a broadcast signal having broadcast transmitter identification information therein. The database has correlation data therein. The data base is operable to generate a first correlation, to generate a second correlation and to generate a correlation signal. The first correlation is based the broadcast transmitter identification information and the first location. The second correlation is based on the first location and one of the first global positioning system satellite and the second global positioning satellite. The correlation signal is based on the second correlation. The mobile phone includes a first receiver, a processing portion, a transmission portion, a second receiver portion and a communication portion. The first receiver portion is operable to receive the broadcast signal. The processing portion is operable to extract the broadcast transmitter identification information from the broadcast signal. The transmission portion is operable to transmit the broadcast transmitter identification information to the database. The second receiver portion is operable to receive the correlation signal. The communication portion is operable to transmit a communication signal to the one of the first global positioning system satellite and the second global positioning satellite, based on the correlation signal. 
     Additional advantages and novel features of the invention are set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of the specification, illustrate an exemplary embodiment of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  illustrates a communication system used for satellite GPS application; 
         FIG. 2  illustrates a conventional communication system associates with satellite a GPS application; 
         FIG. 3  geometrically illustrates how a cell tower operates with cellular network architecture; 
         FIG. 4  illustrates a communication system using the FM Radio Data Service (RDS) station ID correlations in present invention; 
         FIG. 5  illustrates a flowchart of an example process of operating system in accordance with present invention; 
         FIG. 6  illustrates how a mobile phone operates in a fully functioned communication network with a GPS application; and 
         FIG. 7  geometrically illustrates the operation of mobile phone associates with a broadcast antenna in present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with an aspect of present invention, a system is provided to enable a mobile phone to locate and lock onto a GPS satellite using a broadcast from a broadcast station. 
     An example embodiment in accordance with an aspect of present invention will now be described with reference to  FIG. 4  through  FIG. 7 . 
       FIG. 4  illustrates an example communication system that enables a mobile phone to locate and lock onto a GPS satellite using a broadcast from a broadcast station in accordance with an aspect of the present invention. 
     In the figure, a user  202 , is operating a mobile phone  402 , within range of a cell tower  206  and a broadcast station  404 . Further, satellites  104  and  106  are orbiting above Earth  102 . Mobile phone  402  is operable to communicate with cell tower  206 , as indicated by dashed communication line  208 , to receive a broadcast from broadcast station  404 , as indicated by dashed communication line  406 , and to communicate with satellite  104  as indicated by dotted communication line  210 . Broadcast station  404  is able to broadcast information that includes geographical information and station identification information. 
     In accordance with an example aspect of present invention, mobile phone  402  communicates with broadcast station  404  for GPS assistance, as opposed to communicating with cell tower  206  as discussed above with respect to  FIG. 2 . Broadcast station  404  broadcasts information that includes, inter alia, station identification. Mobile phone  402  receives the broadcast information from broadcast station  404  and extracts the station identification information. 
     The station identification information is used to associate a geographical location of broadcast station  404 . Because mobile phone  402  is close enough to broadcast station  404  to receive the broadcast information, then mobile phone  402  may be considered close to the geographical location of broadcast station  404 . 
     Mobile phone  402  is used to communicate with cell tower  206 . Mobile phone  402  communicates, via cell tower  206 , with a station location service provider that correlates the station identification information of broadcast station  404  to a geographic location. The station location service provider then communicates the geographic location to a GPS service provider, which then references a real-time GPS satellite ephemeris that determines the closest orbiting satellite to broadcast station  404 . As mobile phone  402  is within the transmission area of broadcast station  404 , then the closest orbiting satellite to broadcast station  404  is likely the closest orbiting satellite to mobile phone  402 . 
     Once the closest orbiting satellite to mobile phone  402  is identified, the GPS service provider provides communication data to the cell phone service provider, which then provides the communication data to mobile phone  402  via cell tower  206  to enable mobile phone  402  to locate and lock onto the satellite. In the example illustrated in  FIG. 4 , satellite  104  is closer than satellite  106  to broadcast station  404 . This enables mobile phone  402  to communicate with satellite  104  as indicated by dotted communication line  210 . 
     An example process in accordance with an embodiment of present invention will now be described with reference to  FIG. 5 . 
       FIG. 5  is a flowchart of an example process  500  of operating a system in accordance with an aspect of the present invention. Process  500  starts (S 502 ) and mobile phone  402  scans for broadcast information (S 504 ). Scanning may be performed by any known method. Further, non-limiting examples of broadcast information to be scanned include radio broadcast signals and TV broadcast signals. 
     In an example embodiment, mobile phone  402  scans for available FM RDS stations. RDS is a communications protocol standard that originated in the European Broadcasting Union for sending small amounts of digital information using conventional FM radio broadcasts. The RDS system standardizes several types of information transmitted, including time, track/artist info and station identification. 
     If the amplitude of received broadcast information is above a predetermined threshold, the broadcast station that is broadcasting the information will be selected as a target station. Once such a target station is detected (S 506 ), mobile phone  402  will scan the broadcast information for the station&#39;s identification data (S 508 ). 
     If mobile phone  402  is unable to detect the station&#39;s identification data within the broadcast information, then mobile phone  402  scans for new broadcast information (S 504 ). 
     If mobile phone  402  is able to detect the station&#39;s identification data within the broadcast information, then mobile phone  402  extracts the station&#39;s identification data (S 510 ). 
     In this embodiment, mobile phone  402  provides, via cell tower  206 , the station&#39;s identification data to the station location service provider. The station location service provider then determines the geographic location of broadcast station  404  based on the station&#39;s identification data. Because mobile phone  402  is close enough to broadcast station  404  to receive the broadcast information, then mobile phone  402  may be considered close to the geographical location of broadcast station  404  (S 512 ). 
     Once the station location service provider determines the geographical location of broadcast station  404 , and hence the approximate geographical location of mobile phone  402 , the station location service provider communicates the geographical location of broadcast station  404  to a GPS service provider. The GPS service provider then searches the ephemeris for the closest satellite (S 514 ). 
     After determining the closest satellite, the GPS service provider then sends the necessary information about the selected satellite to the cell phone service provider, which then sends the information to mobile phone  402  via cell tower  206 . When mobile phone  402  receives the selected satellite&#39;s contact information, mobile phone  402  uses the information to lock onto the selected satellite (S 518 ). In the example embodiment as illustrated in  FIG. 4 , mobile phone  402  is able to communicate with satellite  104  as indicated by dotted communication line  210 . 
       FIG. 6  illustrates how a mobile phone operates in a fully functioned communication network with a GPS application in accordance with an aspect of the present invention. In the figure, mobile phone  402  is operable to communicate with: cell tower  206  via dashed communication line  208 ; satellite  104  via dotted communication line  210 ; broadcast station  404  via dashed communication line  406 ; and database  602  via dotted communication line  604 . Database  602  may include databases provided by any combination of a GPS service provider, a cell phone service provider and a station location service provider. 
       FIG. 7  geographically illustrates the operation of communication system in accordance with an aspect of the present invention. In the figure, region  302  is populated by a plurality of broadcast stations, each having a corresponding broadcast area. Example broadcast station areas are illustrated in the figure as area  702 , area  704 , and area  706 . Each area is covered by the signal transmitted from an individual broadcast antenna. A mobile phone user, within a broadcast area, communicates via a cell tower geographically located within that broadcast area. 
     Referring back to  FIG. 4 , when user  202  wants to obtain GPS assistance, via mobile phone  402 , mobile phone  402  needs to communicate with a satellite within a GPS network. However, as discussed above, a plurality of satellites  104 ,  106  and  108  are constantly orbiting about Earth. As such, it may be difficult for mobile phone  402  to locate and lock onto a particular satellite. 
     In accordance with an aspect of the present invention, mobile phone  402  is used to receive a broadcast signal from any one of the broadcast stations corresponding to broadcast areas  702 ,  704  and  706 . If any one of the received signals from the broadcast stations corresponding to broadcast areas  702 ,  704  and  706  include identification information that may be used to geographically locate that particular broadcast station, mobile phone  402  retrieves the identification information. Mobile phone  402  then communicates, via cell tower  206 , with a station location service provider that correlates the identification information of the detected broadcast station  404  to a geographic location. A GPS service provider then references a real-time GPS satellite ephemeris that determines the closest orbiting satellite to broadcast station  404 . As mobile phone  402  is within the transmission area of broadcast station  404 , then the closest orbiting satellite to broadcast station  404  is likely the closest orbiting satellite to mobile phone  402 . 
       FIG. 7  differs from  FIG. 3  with the way geographic proximity of the user is determined. In the conventional approach discussed above with respect to  FIG. 3 , user  202  at point  350  is determined by recognizing the cell ID of cell  328  that covers the user in point  350 . In contrast with an aspect of the present invention, a geographic proximity of user  202  at point  350  in  FIG. 7  is determined by identifying the identification information of a broadcast station, for example, any one of the received signals from the broadcast stations corresponding to broadcast areas  702 ,  704  and  706 . 
     In the above discussed embodiments, the identification information is used by a station identification service to determine the geographic location of the broadcast station. In other embodiments, the identification information includes the geographic location, e.g., latitude and longitude data, of the broadcast station. In such embodiments, there is no need to contact a station identification service. In these embodiments, the cell phone may communicate directly with a GPS service provider to correlate the geographical location with the ephemerides to determine the closest orbiting satellite. In still other embodiments, a cell phone may include a database therein that correlates identification information from broadcast stations with corresponding geographic locations. In these embodiments, the cell phone may additionally communicate directly with a GPS service provider to correlate the geographical location with the ephemerides to determine the closest orbiting satellite 
     The foregoing description of various preferred embodiments of the invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments, as described above, were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.