Abstract:
A system and method for wirelessly linking a GPS device ( 12 ) with a portable electronic device ( 14 ) to provide the portable electronic device ( 14 ) with GPS functions. The GPS device ( 12 ) includes a GPS receiver or sensor ( 16 ) operable for receiving OPS satellite signals from a plurality of GPS satellites and a transmitter ( 18 ) coupled with the GPS receiver for wirelessly transmitting information corresponding to the GPS satellite signals. The portable electronic device ( 14 ) includes a receiver for wirelessly receiving the information transmitted by the GPS device ( 12 ) and a display for displaying data corresponding to the GPS satellite signals. The transmitter ( 18 ) of the GPS device ( 12 ) and the receiver of the portable electronic device ( 14 ) 10 preferably wirelessly transmit and receive information via a short range wireless local area network (LAN) using infrared, unlicensed radio, or optical transmission methods. The portable electronic device ( 14 ) further preferably includes a sensor for receiving voice commands from a user and a speaker for communicating audible instructions to the user.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of Ser. No. 10/289,666, filed Nov. 7, 2002 now U.S. Pat. No. 6,768,450, and which is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to navigation devices such as GPS receivers. More particularly, the invention relates to a system and method for wirelessly linking a GPS device with a portable electronic device to provide the portable electronic device with GPS functions. 
   2. Description of the Prior Art 
   The global positioning system (GPS) is an electronic satellite navigation system which permits users to determine their position with respect to the Earth. GPS receivers and other navigational devices continue to grow in popularity and are used in many applications, including recreational activities and automobile and marine navigation. 
   GPS receivers detect and decode signals from a number of satellites orbiting the Earth. The signals from each of these satellites indicate the position of the satellite and the time at which the signals were sent. To decode the satellite signals, known as spread spectrum signals, and thereby calculate desired position and navigational data, a GPS receiver must first “find” or acquire the signals emitted from a minimum number of satellites. Once the receiver is “locked on” to the spread spectrum signals, the user&#39;s global position and other navigational data (e.g., velocity of movement) can be calculated. 
   A typical GPS unit includes (along with other components) a GPS receiver which receives the satellite signals, resident memory in which cartographic data and other location information may be stored, a processor and associated GPS software for determining the location of the unit as a function of the received satellite signals and for accessing and processing data and information in the memory, and a display for displaying the information along with an indication of the unit&#39;s location. The resident memory may be integral with the processor, memory chips coupled with the processor, or may include plug-in memory modules that fit within corresponding memory slots in the receiver. The processor retrieves information from the memory, for example, to display maps and routing instructions to permit a user of the GPS receiver to navigate to a desired location. 
   Portable electronic devices such as cellular telephones, personal digital assistants (PDAs), portable computers, and short range radios, also remain popular. Many GPS users often carry one or more of these portable electronic devices along with a GPS receiver so that they can communicate with others or perform other activities provided by the portable electronic device while navigating with the GPS receiver. Unfortunately, carrying and using multiple devices can be cumbersome, especially while driving, hiking, or performing other activities requiring mental concentration or physical exertion. 
   In recent years, attempts have been made to combine GPS receivers and other types of portable electronic devices to lessen the number of devices that need to be carried and used. For example, many PDAs and cellular phones now come equipped with onboard GPS receivers so that the location of the PDA or phone may be determined and displayed along with other information. Unfortunately, such combined devices are relatively expensive and complicated to use. Many people are therefore reluctant to purchase such combined units because they may rarely need to use the GPS functions and do not want their PDA or phone cluttered with controls for rarely-used functions. Moreover, such combined units require that some of the processing power normally reserved for the cellular phone or PDA be used for GPS functions, thus requiring either more memory and more powerful processors or longer processing times. Another limitation of such combined units is that they only combine GPS functions with a cellular phone or PDA, and not with many other types of portable electronic devices. 
   To alleviate some of these concerns, PDAs and cell phones have been introduced with expansion slots for receiving plug-in GPS receiver modules. The plug-in modules may be inserted into the PDA or phone whenever GPS functions are desired and then removed when not in use. Unfortunately, such plug-in GPS receiver modules are also cumbersome because they require the user to handle and connect two separate devices. Moreover, plug-in GPS receiver modules are not as accurate in determining geographic positioning as dedicated GPS receivers. Another limitation of such plug-in GPS receiver modules is that they are currently designed only for use with PDAs and cellular phones, and not with many other types of portable electronic devices. Moreover, use of these plug-in modules prevents the use of other types of plug-in modules such as expansion memory cards. 
   Therefore, a need exists for a system and/or method for providing GPS functionalities to portable electronic devices without using expensive and complicated combined units and without requiring the use of plug-in GPS receiver modules. 
   SUMMARY OF THE INVENTION 
   The present invention solves the above-described problems and provides a distinct advance in the art of GPS devices and portable electronic devices. More particularly, the present invention provides a navigation system and method for wirelessly linking a GPS device with any portable electronic device to provide GPS functions to the portable electronic device without using expensive and complicated combined units and without requiring the use of plug-in GPS receiver modules. 
   A first embodiment of the navigation system broadly includes a GPS device and a portable electronic device that wirelessly communicate over a short range local area network (LAN). The GPS device in the first embodiment preferably includes a GPS receiver or sensor operable for receiving GPS satellite signals from a plurality of GPS satellites and a transmitter coupled with the GPS receiver for wirelessly transmitting information corresponding to the GPS satellite signals. Importantly, the GPS device does not require a display for displaying location information nor even a processor for determining a location of the device. Rather, the GPS receiver and transmitter may merely receive GPS satellite signals and transmit information relating thereto. This permits the use of a small GPS device which may be worn by a user or clipped on a visor or dash of an automobile or other object. 
   The portable electronic device of the first embodiment includes a receiver for wirelessly receiving the information transmitted by the GPS device and a display for displaying data corresponding to the GPS satellite signals. The portable electronic device also preferably includes a processor and conventional GPS software applications for analyzing the information transmitted by the GPS device and for determining a location of the GPS device as a function thereof. The portable electronic device may also include a user interface and other components conventionally found on cellular phones, PDAs, portable computers, short range radios, and other electronic devices. 
   A second embodiment of the navigation system also broadly includes a GPS device and a portable electronic device that wirelessly communicate over a short range LAN. The GPS device in the second embodiment preferably includes the GPS receiver and transmitter discussed above plus a processor, associated memory, and GPS software for analyzing the GPS satellite signals, determining a location of the GPS device as a function thereof and creating corresponding location information. The transmitter of the GPS device then transmits the location information to the portable electronic device. 
   The portable electronic device of the second embodiment is similar to the portable electronic device  14  of the first embodiment except that it requires no processor and GPS software for analyzing the GPS satellite signals. Instead, the portable electronic device merely displays data corresponding to the location information created and transmitted by the GPS device. This permits the use of portable electronic devices without special GPS software and processing capabilities. 
   In both of the above-described embodiments, the transmitter of the GPS device and the receiver of the portable electronic device preferably transmit and receive the information via a short range wireless LAN using short range radio, infrared, or optical transmission methods. In preferred forms, the transmitter and receiver transmit and receive the information using BlueTooth or WiFi communication protocols. 
   In both embodiments, the GPS device may periodically and automatically transmit the information to the portable electronic device so that the portable electronic device may periodically update the displayed location of the GPS device, or the portable electronic device may periodically poll the GPS device for the information. The time period between updates may be fixed or may be selected by a user. A user of the portable electronic device may also request transmission of updated location information from the GPS device. 
   These and other important aspects of the present invention are described more fully in the detailed description below. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     A preferred embodiment of the present invention is described in detail below with reference to the attached drawing figures, wherein: 
       FIG. 1  is a block diagram of a navigation system constructed in accordance with a first preferred embodiment of the present invention. 
       FIG. 2  is a block diagram of a navigation system constructed in accordance with a second preferred embodiment of the present invention. 
       FIG. 3  is a flow diagram depicting one method of transferring location information between the components of the navigation system. 
       FIG. 4  is a flow diagram depicting another method of transferring location information between the components of the navigation system. 
       FIG. 5  is a flow diagram depicting yet another method of transferring location information between the components of the navigation system 
   

   The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Turning now to the drawing figures, and particularly  FIG. 1 , a navigation system  10  constructed in accordance with a first preferred embodiment of the present invention is illustrated. The navigation system  10  broadly includes a GPS device  12  that wirelessly communications with a portable electronic device  14 . 
   In the first embodiment of the invention, the GPS device  12  preferably includes a GPS receiver or sensor  16  and a transmitter  18 . The GPS receiver  16  either includes a GPS antenna  20  or is coupled with an external GPS antenna and is operable for receiving GPS satellite signals from a plurality of GPS satellites and for delivering information corresponding to the GPS satellite signals to the transmitter  18 . 
   The transmitter  18  is coupled with the GPS receiver  16  and is operable for wirelessly transmitting at least a portion of the information received by the GPS receiver  16 . The transmitter  18  either includes an antenna  22  or may be coupled with an external antenna. The transmitter  18  is preferably a transceiver so that it may both transmit and receive information as described below. 
   The GPS receiver  16  and transmitter  18  are preferably positioned in or on a small housing or circuit board. A clip or other connector  24  may be used to attach the GPS device  12  to an arm band so that it may be worn by a user. Alternatively, the connector  24  may attach the GPS device to a visor or dash of an automobile or other object. 
   Importantly, the GPS device  12  of the first embodiment of the invention does not require a display for displaying location information or a processor and associated GPS software for determining a location of the device. Rather, the GPS receiver  16  and transmitter  18  may merely receive GPS satellite signals and transmit information relating thereto to the portable electronic device  14  as described below. This permits the use of a very small GPS device which can be easily worn by a user or attached to another object as discussed above. 
   The portable electronic device  14  may be a cellular telephone, PDA, portable computer, combined cellular phone/computer, radio frequency communications device, or any other known consumer or commercial electronic device. The portable electronic device  14  of the first embodiment of the invention includes a receiver  26  for wirelessly receiving the information transmitted by the GPS device  12  and a processor  28  coupled with the receiver  26  for analyzing the information. 
   As with the transmitter  18  of the GPS device  12 , the receiver  26  is preferably a transceiver operable to both receive and transmit information. The receiver  26  either includes an antenna  30  or may be coupled with an external antenna. 
   The processor  28  is coupled with the receiver  26  for receiving and analyzing the information transmitted by the GPS device  12 . The processor  28  preferably includes, or is coupled with, memory  32  for storing conventional GPS software applications which determine a location of the GPS device as a function of the information transmitted by the GPS device  12 . The same or other memory  34  may store cartographic map data or other information and data conventionally used with GPS devices. The processor  28  may be dedicated for GPS functions only and coupled with another processor of the portable electronic device  14  or may be a dual-function device that both provides GPS functions and other functions related to the portable electronic device  14  such as telephone or PDA functions. 
   The portable electronic device  14  may also include a display  36  for displaying information or data corresponding to the calculated location of the GPS device  12 , and a user interface  38  for permitting a user to enter data and information into the processor  28 . The display  36  is preferably a liquid crystal display but may use any other conventional display technology. The user interface  38  may include control buttons for operating drop-down menus or may be an alpha numeric keypad. 
   The transmitter  18  of the GPS device  12  and the receiver  26  of the portable electronic device  14  preferably wirelessly transmit and receive information via a short range wireless LAN using infrared, unlicensed radio, or optical transmission methods. In preferred forms, the transmitter  18  and the receiver  26  transmit and receive information using BlueTooth or WiFi communication protocols. BlueTooth and WiFi devices are designed to transmit short bursts or packets of data over short ranges using unlicenced high-frequency channels such as the 2.4 GHz frequency band. Such communication protocols typically establish a frequency-hopping radio link using many different frequencies at approximately 1 MHz intervals to give a high degree of immunity from interference with other transmissions. 
   The portable electronic device  14  may also include a transmitter  40  and antenna  42  operable to transmit location information to a remote device. The transmitter may, for example, transmit the location of the GPS device  12  to a remote base station or to another portable electronic device such as a cellular phone. The transmitter  40  may be a short range Family Radio Service (FRS) transmitter, a cellular radio transmitter, or any other conventional transmitting device. 
     FIG. 2  illustrates a navigation system  100  construed in accordance with a second embodiment of the present invention. As with the first embodiment, the navigation system  100  broadly includes a GPS device  102  that wirelessly communications with a portable electronic device  104 . 
   In the second embodiment, the GPS device  102  includes a GPS receiver  106 , transmitter  108 , and antenna  109  that operate substantially the same as these same components of the first embodiment. However, in the second embodiment, the GPS device  102  also preferably includes a processor  110  and memory  112  for storing GPS software operable for analyzing the GPS satellite signals received by the GPS receiver  106 , for determining a location of the GPS device  102  as a function thereof, and for generating location information corresponding to the calculated location. The processor  110  delivers the location information to the transmitter  108  for transmission to the portable electronic device  104 . 
   The GPS device  102  may also include a user interface  114  for permitting a user to enter data and information into the processor  110  and a display  116  for displaying the calculated location of the GPS device  102 . The memory  112  or other memory  118  may store cartographic map data or other useful navigational information that may be displayed on the display  116 . 
   The portable electronic device  104  of the second embodiment is similar to the portable electronic device  14  of the first embodiment and may be a cellular phone, PDA, portable computer, combined cellular phone/computer, radio frequency communications device, or any other known consumer or commercial electronic device. The portable electronic device  104  includes a receiver  120  and antenna  121  for wirelessly receiving information transmitted by the GPS device  102 , a processor  122  coupled with the receiver  120 , a user interface  124  coupled with the processor  122 , and a display  126  coupled with the processor  122 . The portable electronic device  104  may also include a transmitter  128  and antenna  130  operable to transmit location information to a remote base station or to another portable electronic device as described above. Importantly, the portable electronic device  104  of the second embodiment does not require GPS software and processing capabilities for determining a location of the GPS device  102 . Instead, such tasks are performed by the GPS device  102  as discussed above. 
   As with the first embodiment, the GPS device  102  and portable electronic device  104  of the second embodiment preferably wirelessly transmit and receive information via a short range wireless LAN using infrared, unlicensed radio, or optical transmission methods. In preferred forms, the transmitter  108  and receiver  120  transmit and receive information using BlueTooth or WiFi communication protocols. 
   In both the first and second embodiments of the invention and other embodiments, information may be sent between the GPS device  12 ,  102  and the portable electronic device  14 ,  104  via several methods.  FIG. 3  depicts the steps in one method in which the GPS device  12 ,  102  periodically and automatically transmits information to the portable electronic device  14 ,  104 . Specifically, as depicted in step  300  of  FIG. 3 , the GPS device  12 ,  102  initially receives GPS satellite signals and transmits information corresponding to these received GPS satellite signals with its transceiver. The transceiver of the portable electronic device  14 ,  104  then receives the information as depicted in step  302 . The information is then passed to the processor of the portable electronic device  14 ,  104  and displayed on its display as described above and as depicted in step  304 . After a predetermined amount of time has elapsed, these steps are repeated when the GPS device  12 ,  102  transmits updated information as depicted in step  300 . The time period between transmissions of the information may be fixed (for example every 30 seconds) or may be selected by a user (for example between 1 second and 5 minutes). 
     FIG. 4  depicts another method of transferring information between the GPS device  12 ,  102  and the portable electronic device  14 ,  104  in which the portable electronic device  14 ,  104  periodically polls the GPS device  12 ,  102  for the information. Specifically, as depicted in step  400  of  FIG. 4 , the receiver of the portable electronic device  14 ,  104  initially transmits a request for the most recent information to the transmitter of the GPS device  12 ,  102 . The GPS device  12 ,  102  then transmits the information to the portable electronic device  14 ,  104  as depicted in step  402 . The portable electronic device  14 ,  104  receives the information and displays it on its display as described above and as depicted in step  404  of  FIG. 4 . These steps are repeated after a predetermined amount of time. As with the first transmission method described above, the time period between transmissions may be fixed or selected by a user. 
     FIG. 5  depicts yet another method of transmitting information between the GPS device  12 ,  102  and the portable electronic device  14 ,  104  in which a user of the portable electronic device  14 ,  104  requests the information. Specifically, as depicted in step  500  of  FIG. 5 , a user of the portable electronic device  14 ,  104  may enter a command into the user interface to request updated location information. The portable electronic device  14 ,  104  then transmits to the GPS device  12 ,  102  a request for such information as depicted in step  502 . The GPS device  12 ,  102  then transmits the information to the portable electronic device  14  as depicted in step  504 . The portable electronic device  14 ,  104  then displays the information on its display as discussed above and as depicted in step  506 . At any time, the user of the portable electronic device  14 ,  104  may repeat these steps by once again entering a request for updated location information. 
   Although the invention has been described with reference to the preferred embodiment illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.