Abstract:
An apparatus for location determination includes a location determination receiver configured to receive location determination signals, a location determination signal quality assessment component configured to assess a quality of received location determination signals, and a location determination processor responsive to an output of the location determination signal quality component. The apparatus determining a location of the location determination receiver based on the location determination signals that are received during time periods when the location determination signal meets or exceeds a location determination signal quality threshold. A method for location determination is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 12/052,473 filed on Mar. 20, 2008 and issued on Oct. 26, 2010 as U.S. Pat. No. 7,821,456, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60/896,104, filed on Mar. 21, 2007, the disclosure of which are expressly incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     1. Field 
     The method and apparatus are directed generally to efficient utilization of location determination signals to determine location in noisy environments, and more particularly to efficient utilization of location determination signals for location determination in noisy environments that results in reduced power usage and/or increased computing resources. 
     2. Related Art 
     There currently exist a number of location determination methods and apparatuses. For example, one common system is the Global Positioning System (GPS) which utilizes a constellation of medium earth orbit satellites that transmit precise microwave signals. These signals allow a suitable receiver to determine a position location. 
     GPS devices typically employ a time consuming process to find GPS signals and subsequently solve location equations to determine the location of a user and their mobile station. 
     Many GPS systems exist on platforms or are used in environments in which other RF receivers such as cellular telephones, wireless fidelity (WiFi), Bluetooth, Ultra-wideband, Wi-MAX, or any other radio frequency interferences from other communication devices interfere with GPS reception. Similarly GPS signals may fade or become degraded due to changing environmental conditions. Attempts to determine location in poor reception conditions may cause various problems, including but not limited to, inefficient use of power resources available to a GPS device. 
     SUMMARY 
     In accordance with an aspect of the invention, a method and apparatus are provided to predict various parameters in a noisy environment and control a GPS receiver to avoid wasting power resources and/or computing resources during periods of noise. The result is that there is an improvement in the use of the GPS samples in noisy environments, particularly when the magnitude of noise fluctuates, while minimizing the adverse affect on location determination. This further results in a shorter time to first fix in obtaining a location determination in noisy environments. Various advantages may result including an improvement in the power consumption of the GPS apparatus in noisy environments and especially during acquisition mode, an improvement in the tracking mechanism in a number of cases, and better service of the various location applications. Further benefits will be apparent in the discussion that follows. 
     The invention may be implemented in a number of ways. According to an embodiment of the invention an apparatus for location determination includes a location determination receiver configured to receive location determination signals, a location determination signal quality assessment component configured to assess a quality of received location determination signals, and a location determination processor responsive to an output of the location determination signal quality component for determining a location of the location determination receiver based on the location determination signals that are received during time periods when the location determination signal meets or exceeds a location determination signal quality threshold. 
     According to another embodiment of the invention a method for location determination includes determining whether or not there is radio frequency interference caused by a transmitter, receiving location determination signals for determining a location based on the location determination signals, and controlling a processing of received location determination signals in response to the determination of radio frequency interference caused by the transmitter. 
     Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary and the following detailed description provide examples and are intended to provide further explanation without limiting the scope of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate embodiments of the invention. No attempt is made to show structural details in more detail than may be necessary for a fundamental understanding of teaching principles and the various ways in which the claimed invention may be practiced. In the drawings: 
         FIG. 1  is an exemplary block diagram of a mobile device configured in accordance with an embodiment; 
         FIG. 2  shows a mobile device configured in accordance with another embodiment; 
         FIG. 3  shows a mobile device configured in accordance with another embodiment; 
         FIG. 4  shows examples of wave patterns; 
         FIG. 5  shows a flow diagram of a process for operating a mobile device in accordance with an embodiment; 
         FIG. 6  shows a vehicle control system in which the devices are configured in accordance with an embodiment; and 
         FIG. 7  shows a cellular telephone in which devices are configured in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments of the invention and various features and details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as would be apparent to a skilled artisan, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure teaching principles of embodiments of the invention. The examples and embodiments herein should not be construed as limiting the scope of the claimed invention, which is defined solely by the appended claims and applicable law. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings. 
       FIG. 1  is a block diagram showing a device, such as a mobile device, a cellular telephone, or PDA constructed and arranged in accordance with an embodiment. In particular,  FIG. 1  shows a mobile station  100  that may include an antenna  112  that is used to receive GPS signals from one or more GPS satellites of a GPS satellite constellation. The mobile station  100  may further include a band pass filter  102  operating as is well known in the art to select a particular frequency band to pass through to an output. The output of the band pass filter  102  is input to a low noise amplifier (LNA)  104 . The low noise amplifier is a special type of amplifier used in communication systems to amplify weak signals received by the antenna  112 . The output of the amplified signal from the low noise amplifier  104  is then fed to a second band pass filter  106 . The second band pass filter  106  passes frequencies within a certain range and rejects or attenuates other frequencies. The band pass filter  106  passes some signals on to the GPS receiver  108 . 
     The mobile station  100  further includes a prediction component  110 . The prediction component  110  may be used to predict start and/or stop times of different signals that interfere with the GPS reception resulting in undesirable noise that may cause the mobile station to operate with a lower performance and/or higher power usage. The mobile station  100  may also include a transmitter  114 . The transmitter  114  may be a cellular transmitter, a WiFi transmitter, a Bluetooth transmitter, an Ultra-wideband transmitter, a Wi-MAX transmitter, and the like. The transmitter  114  transmits signals from antenna  116 . The signals may cause interference within the mobile station  100 . The prediction component  110  controls the GPS receiver  108  to operate at those times when the signals from transmitter  114  do not generate enough interference to keep the GPS receiver  108  from being able to determine a location. In particular, the prediction component  110  may use knowledge of when other transmitters/receivers are operating in a manner that interferes. The prediction component  110  may also base controlling on actual measurement software and the like. The prediction component  110  may operate according to the process described in further detail below or may use another type of process to control the GPS receiver  108  to operate at low interference times based on the interference generated at least by the transmitter  114 . There may also be signal degradation due to environmental conditions etc. 
     The prediction component  110  may allow for non-continuous acquisition and/or tracking of GPS signals that may utilize short non-continuous bursts of samples of the signal, while providing a user with a continuous indication of location during movement of a GPS receiver unit  118  (the user may not even be aware that the GPS signals are acquired non-continuously). 
     The prediction component  110  may also determine time slots of suitable use GPS signals (either as a function of knowledge of system noise or from within the signal itself), only acquiring GPS signals during non-continuous time slots in which the signals are suitable and then only processing the suitable signals for making location determination. 
     The prediction component  110  may also acquire GPS signals, determining a characteristic of the signals that may be suitable, and then performing different processes as a function of the GPS signal characteristics. For example, when a signal is of insufficient quality (determination may be made as function of knowledge of system noise or signal analysis), the prediction component  110  may not use the poor signals for making any location determination. 
     As further shown in  FIG. 1 , the prediction component  110  is shown as a separate component within the mobile station  100 . As shown in  FIG. 2 , both the prediction component  110  and the GPS receiver  108  may be combined in a single component. Of course other arrangements or a mobile station having additional receivers/transmitters or an additional arrangement of components is contemplated. 
       FIG. 3  shows an interconnection between the transmitter  114  and the prediction component  110 . This interconnection  302  provides a signaling input from the transmitter  114  to the prediction component  110  providing an indication of the start and/or stop time of possible sources of interfering signals to the prediction component  110 , so that the prediction component  110  may more accurately control the operation of the GPS receiver  108 . The interfering signals (in a non-physics sense) cause undesirable noise, signal degradation, or may actually, but not necessarily “interfere.” 
     The determination of whether or not there is interference by the prediction component  110  may be determined by prior or real time knowledge of times when the other transceivers are in question, for example prediction component  110  may have knowledge of TDMA time slots, or when a call is being received, paging signals are received, etc. or may be made by calculations, measurements, or both. In particular, the interfering signals from a transmitter that is on the same platform (or adjacent platform) may be based on known protocols, frequencies, amplitudes, time durations, signaling, and so on. These known actions may be stored in a look-up table or calculated in the prediction component  110 . Additionally or alternatively, the determination of interfering signals may be determined by radio frequency measurement or other sensing that may result in the determination of a noisy environment or other interfering signals. 
     It should be noted that the particular arrangement of the mobile station  100  shown in  FIG. 1  is presented as an example. That is to say that the band pass filter  102 , low noise amplifier  104  and band pass filter  106  may be replaced by greater or fewer components. Additionally, the fact that there are two antennae  112 ,  116  is merely for this example and there may be greater or fewer antennae providing transmission and reception of any number of wireless signals including MIMO arrays, diversity receivers, etc. Now the process that may be used in the mobile station  100  will be described in greater detail below. 
       FIG. 4  shows several examples of wave patterns of GPS signal samples and other signals that interfere causing degradation of the GPS signal. In particular  FIG. 4  shows two separate radio frequency signals plotted with respect to time. The upper line shows GPS samples during three time periods. The first time period A on the left, time period B in the middle and time period C on the right. The interfering signal time plot (interferer) shown in the lower line shows no interfering signals during time period A, shows the existence of interfering signals during time period B, and shows no interfering signals during time period C. Accordingly, GPS samples acquired during the period A may be considered good samples in that a GPS apparatus may be able to readily use these samples to determine a location. On the other hand, the GPS samples acquired during the period B may be considered “bad samples” and the GPS apparatus may not be able to calculate/determine a location or may require more time or processing resources to calculate/determine a location when using samples acquired during period B. The subsequent time period C, samples are good samples, as the interfering signals are no longer present in the spectrum and a location may be readily determined using samples acquired in time period C. 
     The apparatus described above and the process described below addresses these cases. As shown in case one, the GPS system attempts to obtain a clean set of GPS signals during time period A. The GPS apparatus requires a certain amount of time in order to obtain a good sample. This time period is referred to as Δt req . In case one, the GPS apparatus starts the reception process during time period A. However, the reception time (Δt) is not long enough and extends into time period B during which period interfering signals are transmitted or received. Accordingly, the apparatus and process of the invention may suspend or stop the GPS reception and/or location determination process during interference, and knowing or having a good prediction of when the interfering signals may stop, may continue or restart the sampling process at the start of time period C. Accordingly, the GPS system is able to reduce power consumption and save computing resources. In case two, also shown in  FIG. 4 , the requested start of a sampling process occurs during time period B. The prediction component and process of the invention may suspend the sampling process until time period C at which time the receiver may obtain a full clean sample (Δt&gt;Δt req ). Again processor resources are saved and power consumption is reduced. 
     It should be noted that Δt req  is the time that a GPS receiver needs to receive GPS signals to make a location determination. At must be greater than Δt req . Δt req  may vary depending on the GPS system and may also vary depending on three different scenarios. The three different scenarios are cold, warm and hot. The cold scenario is with respect to when the GPS receiver has missing or in accurate estimates of its position, velocity, time and/or visibility of any GPS satellites. In this regard, the receiver must systematically search for all possible signals from the constellation of satellites. After acquiring one or more satellite signals, the receiver must then obtain information regarding other satellites and in particular the almanac. The almanac is typically transmitted from the satellites over several minutes. The next scenario is the warm scenario. The receiver has some estimates of the current time and current position and may have some valid almanac data. However, it still must acquire each satellite signal and obtain the satellites detail orbital information. Finally, the hot scenario is when a GPS apparatus has a valid time, position, almanac and other data enabling a rapid acquisition of satellite signals. Accordingly, the Δt req  for a time to first fix (TTFF) is based on whether or not a GPS apparatus is currently in a cold, warm, or hot scenario. The process in which the GPS system may operate will now be discussed with reference to  FIG. 5 . It should be noted that the apparatus shown in  FIGS. 1 to 3  may use a different process than described herein providing the same functionality. 
       FIG. 5  shows an exemplary process operating according to the principles of an embodiment of the invention. In particular,  FIG. 5  shows a process for reducing power consumption and/or saving processing resources for a GPS receiver operating in noisy environments. The process  500  shown in  FIG. 5  includes a communications manager process  502  for the efficient utilization of location determination signals. The first step in the process may be to determine whether or not there is any current interfering signals or other type of noise within the environment as shown by  504 . If there is no current interfering signals or noise, then the logic may move forward to  512  and the GPS receiver may obtain a fix on the various signals from the satellite of the GPS constellation. Thereafter, the radio frequency samples from the GPS system may be obtained as shown in  514 . Next, the GPS base band processing may begin as shown in  516 , and the position calculation process may begin and be completed as shown in  518 . 
     If however on the other hand, there are interfering signals or other noisy signals determined in  504 , the processing may not move to GPS  512 , but instead may stop and execute the process described in further detail below. The determination of whether or not there is interference may be found by calculations, measurements, or both. In particular, the interfering signals from a transmitter or received in a receiver may be based on known protocols, frequencies, amplitudes, time durations, signaling, and so on that are caused by the transmitter that is on the same platform or in the same mobile station as the GPS receiver. In this regard, known actions may cause interference, accordingly such actions may be signaled to the GPS receiver to provide an indication of interference or possible interferences in  504 . Additionally, the determination of interference as shown in  504  might be via some form of radio frequency measurement or other sensing that may result in the determination of a noisy environment or other interference. In any event, any type of known interference and any ability to ascertain that there is a noisy environment and/or interference is within the scope and spirit of the invention in determination of interference as shown in  504 . 
     In  506 , a determination is made whether or not the start time and/or stop time are known for the interference. In this regard, the transmitter that is part of the platform of the GPS receiver or mobile station is operating may provide and indication on the length of time (start and/or stop time) of the transmission of interfering signals. Alternatively the period of time may be known, for example set by standards. Such information may be stored in a look up table, such that when a particular activity is used or started, that information may be obtained in the look up table to provide a start and/or stop time that may be used for further processing. In that regard, as shown in  510 , when a start and stop time is known, the GPS receiver may stop for a predetermined time until the known interference may be gone. This works for each of the cold, warm, hot scenarios. After the predetermined time has lapsed then the process may flow to the GPS radio frequency sample  514  and may go forward in accordance with the process that is described above. 
     On the other hand if the start and stop time are not known in  506 , then the flow of logic may move to  508 . In  508 , the process may stop until the interference has stopped regardless of whether or not the GPS receiver is currently operating in a cold, warm or hot scenario. This may allow whatever interference and/or noisy environment currently complicating the position calculation process to change or stop. Once the interference has stopped, then the process may again start obtaining the GPS signals as described in  514 ,  516 , and  518  described above. 
     Referring now to  FIGS. 6 and 7  various examples of applications in which embodiments of the invention may be implemented are shown. 
     Referring now to  FIG. 6 , the apparatus and process may be implemented in a location determination system of a wireless system  1348  and location determination system  1380  of a vehicle  1330 . Accordingly, the apparatus allowing the wireless system  1348  and location determination system  1380  to be more efficient. In some implementations, the vehicle may include a power train control system  1332  that receives inputs from one or more sensors  1336  such as temperature sensors, pressure sensors, rotational sensors, airflow sensors and/or any other suitable sensors and/or that generates one or more output control signals from an output  1338  such as engine operating parameters, transmission operating parameters, and/or other control signals. 
     The vehicle may also include other control systems  1340 . The control system  1340  may likewise receive signals from input sensors  1342  and/or output control signals to one or more output devices  1344 . In some implementations, control system  1340  may be part of an anti-lock braking system (ABS), a navigation system, a telematics system, a vehicle telematics system, a lane departure system, an adaptive cruise control system and the like. Still other implementations are contemplated. 
     A power train control system  1332  may communicate with mass data storage  1346  that stores data in a nonvolatile manner. Mass data storage  1346  may include optical and/or magnetic storage devices for example hard disk drives HDD and/or DVDs. Power train control system  1332  may be connected to memory  1347  such as RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage. Power train control system  1332  also may support connections with the wireless system  1348  that may be implemented as a WLAN via a WLAN network interface. The control system  1340  may also include mass data storage, memory and/or a WLAN interface (all not shown). The wireless system  1348  may be any type of wireless communication protocol. 
     Referring now to  FIG. 7 , the apparatus and process may be embodied in a cellular phone  1450  that may include a cellular antenna  1451  and a location determination component  1468  so as to make the same more efficient. The invention may implement either or both signal processing and/or control circuits, which are generally identified in  FIG. 7  at  1452 . In some implementations, cellular phone  1450  includes a microphone  1456 , an audio output  1458  such as a speaker and/or audio output jack, a display  1460  and/or an input device  1462  such as a keypad, pointing device, voice actuation and/or other input device. Signal processing and/or control circuits  1452  and/or other circuits (not shown) in the cellular phone  1450  may process data, perform coding and/or encryption, perform calculations, format data and/or perform other cellular phone functions. 
     Although reference is made to some specific wireless protocols, any wireless protocol is within the scope of the invention. For example, Bluetooth, wireless-fidelity (Wi-Fi—IEEE 802.11), fixed wireless access (WiMAX—IEEE 802.16), ultra wideband (UWB), WCDMA (wideband code-division multiple access) or any other known technology using a licensed or unlicensed frequency band. Similarly, although GPS is referenced, the position location determination signals may include GLONASS signals or Galileo signals. Moreover, any future enhancement of a current protocol or any future wireless protocol is contemplated for use with the invention. 
     Although the invention has been described in terms particular embodiments, those skilled in the art will recognize that the invention can be practiced with modifications in the spirit and scope of the appended claims. These examples given above are merely illustrative and are not meant to be an exhaustive list of all possible designs, embodiments, applications or modifications of the invention.