System and method for correlating broadcast station with geographic proximity on earth

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.

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'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'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. 1illustrates a conventional satellite communication system used for a satellite GPS application. In the figure, satellite104, satellite106and satellite108are in orbits around Earth102in orbit110, orbit112and orbit114, respectively. The distance from any specific location on Earth102to each of satellite104, satellite106and satellite108varies with time.

FIG. 2illustrates a satellite PGS application used in a conventional communication system. In the figure, a user202, is operating a mobile phone204, within range of a cell tower206. Further, satellites104and106are orbiting above Earth102. Mobile phone204is operable to communicate with cell tower206, as indicated by dashed communication line208, and to communicate with satellite104, as indicated by dotted communication line210.

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 tower206communicates with satellites104and106as indicated by dotted communication lines212and214, respectively. The satellites additionally are able to communicate with one another, for example, satellite104and106communicate with each other as indicated by dotted communication line216. Orbiting around Earth, each satellite is able to communicate to the cellular network by communicating with a plurality of cell towers.

FIG. 3geographically illustrates a conventional cellular network. In the figure, region302is populated by multiple cells, a portion of which are illustrated as cells304through348(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 toFIG. 2, if user202were located at point350, which is within cell328, then user202would communicate with others via cell tower206within cell328.

Referring back toFIG. 2, when user202wants to obtain GPS assistance, via mobile phone204, mobile phone204needs to communicate with a satellite within a GPS network. However, as discussed above, a plurality of satellites104,106and108are constantly orbiting about Earth. As such, it may be difficult for mobile phone204to 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 phone204is used to communicate with cell tower206. Cell tower206recognizes its current cell identification information, for example the identification information of cell328inFIG. 3. Conventional databases list geographical location of cell towers, which includes cell tower206. Further, some conventional GPS service providers correlate the geographical location of cell towers to the plurality of GPS satellites through an ephemeris database.

Cell tower206is able to contact any one of many cell phone service providers having information that corresponds to the geographical location of cell tower206. 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 tower206. As mobile phone204is within the transmission area of cell tower206, then the closest orbiting satellite to cell tower206is likely the closest orbiting satellite to mobile phone204.

Once the closest orbiting satellite to mobile phone204is identified, the GPS service provider provides communication data to the cell phone service provider, which then provides the communication data to mobile phone204via cell tower206to enable mobile phone204to locate and lock onto the satellite. In the example illustrated inFIG. 2, satellite104is closer than satellite106to cell tower206. This enables mobile phone204to communicate with satellite104as indicated by dotted communication line210.

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.

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 toFIG. 4throughFIG. 7.

FIG. 4illustrates 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 user202, is operating a mobile phone402, within range of a cell tower206and a broadcast station404. Further, satellites104and106are orbiting above Earth102. Mobile phone402is operable to communicate with cell tower206, as indicated by dashed communication line208, to receive a broadcast from broadcast station404, as indicated by dashed communication line406, and to communicate with satellite104as indicated by dotted communication line210. Broadcast station404is able to broadcast information that includes geographical information and station identification information.

In accordance with an example aspect of present invention, mobile phone402communicates with broadcast station404for GPS assistance, as opposed to communicating with cell tower206as discussed above with respect toFIG. 2. Broadcast station404broadcasts information that includes, inter alia, station identification. Mobile phone402receives the broadcast information from broadcast station404and extracts the station identification information.

The station identification information is used to associate a geographical location of broadcast station404. Because mobile phone402is close enough to broadcast station404to receive the broadcast information, then mobile phone402may be considered close to the geographical location of broadcast station404.

Mobile phone402is used to communicate with cell tower206. Mobile phone402communicates, via cell tower206, with a station location service provider that correlates the station identification information of broadcast station404to 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 station404. As mobile phone402is within the transmission area of broadcast station404, then the closest orbiting satellite to broadcast station404is likely the closest orbiting satellite to mobile phone402.

Once the closest orbiting satellite to mobile phone402is identified, the GPS service provider provides communication data to the cell phone service provider, which then provides the communication data to mobile phone402via cell tower206to enable mobile phone402to locate and lock onto the satellite. In the example illustrated inFIG. 4, satellite104is closer than satellite106to broadcast station404. This enables mobile phone402to communicate with satellite104as indicated by dotted communication line210.

An example process in accordance with an embodiment of present invention will now be described with reference toFIG. 5.

FIG. 5is a flowchart of an example process500of operating a system in accordance with an aspect of the present invention. Process500starts (S502) and mobile phone402scans for broadcast information (S504). 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 phone402scans 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 (S506), mobile phone402will scan the broadcast information for the station's identification data (S508).

If mobile phone402is unable to detect the station's identification data within the broadcast information, then mobile phone402scans for new broadcast information (S504).

If mobile phone402is able to detect the station's identification data within the broadcast information, then mobile phone402extracts the station's identification data (S510).

In this embodiment, mobile phone402provides, via cell tower206, the station's identification data to the station location service provider. The station location service provider then determines the geographic location of broadcast station404based on the station's identification data. Because mobile phone402is close enough to broadcast station404to receive the broadcast information, then mobile phone402may be considered close to the geographical location of broadcast station404(S512).

Once the station location service provider determines the geographical location of broadcast station404, and hence the approximate geographical location of mobile phone402, the station location service provider communicates the geographical location of broadcast station404to a GPS service provider. The GPS service provider then searches the ephemeris for the closest satellite (S514).

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 phone402via cell tower206. When mobile phone402receives the selected satellite's contact information, mobile phone402uses the information to lock onto the selected satellite (S518). In the example embodiment as illustrated inFIG. 4, mobile phone402is able to communicate with satellite104as indicated by dotted communication line210.

FIG. 6illustrates 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 phone402is operable to communicate with: cell tower206via dashed communication line208; satellite104via dotted communication line210; broadcast station404via dashed communication line406; and database602via dotted communication line604. Database602may include databases provided by any combination of a GPS service provider, a cell phone service provider and a station location service provider.

FIG. 7geographically illustrates the operation of communication system in accordance with an aspect of the present invention. In the figure, region302is populated by a plurality of broadcast stations, each having a corresponding broadcast area. Example broadcast station areas are illustrated in the figure as area702, area704, and area706. 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 toFIG. 4, when user202wants to obtain GPS assistance, via mobile phone402, mobile phone402needs to communicate with a satellite within a GPS network. However, as discussed above, a plurality of satellites104,106and108are constantly orbiting about Earth. As such, it may be difficult for mobile phone402to locate and lock onto a particular satellite.

In accordance with an aspect of the present invention, mobile phone402is used to receive a broadcast signal from any one of the broadcast stations corresponding to broadcast areas702,704and706. If any one of the received signals from the broadcast stations corresponding to broadcast areas702,704and706include identification information that may be used to geographically locate that particular broadcast station, mobile phone402retrieves the identification information. Mobile phone402then communicates, via cell tower206, with a station location service provider that correlates the identification information of the detected broadcast station404to a geographic location. A GPS service provider then references a real-time GPS satellite ephemeris that determines the closest orbiting satellite to broadcast station404. As mobile phone402is within the transmission area of broadcast station404, then the closest orbiting satellite to broadcast station404is likely the closest orbiting satellite to mobile phone402.

FIG. 7differs fromFIG. 3with the way geographic proximity of the user is determined. In the conventional approach discussed above with respect toFIG. 3, user202at point350is determined by recognizing the cell ID of cell328that covers the user in point350. In contrast with an aspect of the present invention, a geographic proximity of user202at point350inFIG. 7is 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 areas702,704and706.

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