KR20060065590A - Method and apparatus for communication of gps ephemeris - Google Patents

Abstract

Satellite ephemeris data associated with satellite vehicles in a Global Positioning System (GPS) based position location system can be selectively transmitted to a mobile station within a wireless communication system. The mobile station can selectively request satellite ephemeris data from a Position Determination Entity (PDE) that is in communication with one or more GPS satellite vehicles (SV). The mobile station forecasts the satellite vehicles that theoretically are available. Then, the mobile station checks to see if valid ephemeris data is locally stored. If ephemeris data is desired and not locally available, the mobile station transmits a selective ephemeris request to the PDE and receives, in response to the request, the ephemeris corresponding to the SV identified in the ephemeris request. The selective ephemeris request and selective satellite update method can be implemented in accordance with presently available position location standards.

Description

METHOD AND APPARATUS FOR COMMUNICATION OF GPS EPHEMERIS}

background

Related Applications

This application claims priority to US Provisional Application No. 60 / 483,209, filed June 27, 2003.

Technical Field

The method and apparatus of the present invention relate to the field of position determination. More specifically, the present invention relates to the communication of GPS ephemeris data.

Description of related technology

The wireless location determination system is used to determine the location of the device. Often, the device is a mobile or portable device that may operate from battery power, and the device may not be tied to any fixed location by a wired communication link.

There are a number of design concerns with wireless positioning systems. Of course, positioning accuracy is one of the concerns. System sensitivity, acquisition time, and power dissipation are also design concerns addressed in positioning systems. Typically, wireless positioning systems include a trade-off of design constraints in an attempt to obtain a relative optimization of each system concern.

As wireless communication systems become more prevalent, there is a need to integrate some types of location capabilities. In a wireless communication system, such as a wireless telephone system, it may be desirable to be able to measure the position of a mobile device, such as a wireless telephone handset. Indeed, in the United States, improved emergency wireless service with the ability to determine the location of a handset has become mandatory for wireless telephone providers. Wireless service providers, along with equipment manufacturers, have invented a variety of positioning systems that can provide the location of mobile devices such as portable handsets.

The positioning system, which may be utilized by the mobile device, may be based on a global positioning system (GPS). In the global positioning system, there are about 24 satellites orbiting the earth. Each satellite transmits a carrier frequency modulated with a pseudo random noise (PRN) code sequence. The PRN code commonly used by civilian-based GPS receivers is referred to as coarse acquisition (C / A) code. Each satellite transmits a different PRN code. In GPS, a GPS receiver receives signals from multiple satellites and determines the distance from each satellite to triangulate the position of the receiving device.

In general, satellite orbits may be determined using prediction algorithms. However, in order to obtain accurate position measurements using GPS, accurate satellite position is required. The GPS satellites transmit ephemeris data that accurately identifies the satellite's position in its orbit. However, since the satellite's position typically varies with a number of factors, the satellite periodically updates the ephemeris data. The satellite vehicle (SV) can update the ephemeris data every hour. However, satellite ephemeris data is typically valid for a period of about 4 hours. Ephemeris data transmitted by the SV includes a "Time of Ephemeris" field, and typically, Ephemeris data is valid for a four hour period centered near the time of Ephemeris.

The time required for the GPS SV to transmit SV ephemeris data as well as almanac data associated with the SV location may be rather long. For example, the time to transmit one GPS frame having a sub-frame containing SV ephemeris and SV satellite force data may take 12.5 minutes or more. A mobile device, such as a mobile station in a wireless communication system, may need to receive all SV ephemeris and satellite force data before establishing initial position determination. Also, mobile devices typically need to identify available satellites and determine a pseudo-range for each available satellite for initial positioning. In addition, initial positioning may be referred to as a first or initial fix. For mobile stations, the time required for delay plus (+) positioning with respect to received SV satellite power and ephemeris data may be greater than the desired time or a certain maximum time.

Accordingly, what is needed is a method and apparatus for reducing the time for positioning in a GPS-based positioning system. The method and apparatus should reduce the time required to obtain the first fix. It is also particularly desirable to be able to implement the method and apparatus in current available wireless communication location determination systems in a manner compatible with conventional standards.

summary

The method and apparatus of the present invention are for selectively requesting and downloading ephemeris data based at least in part on the availability of a satellite vehicle (SV). The mobile station can determine the available SV from the series of SVs. The mobile station can also determine whether the current ephemeris data associated with each available SV is valid. The mobile station can also selectively request ephemeris data for the SV for which the current ephemeris data is invalid.

One aspect of the method of the present invention for selectively requesting positioning data includes determining at the mobile station a plurality of available positioning signal sources, and determining whether current positioning data associated with the plurality of available positioning signal sources is valid. Steps. If the current positioning data is invalid, the mobile station can optionally request the positioning data.

The method can include receiving satellite force of positioning data corresponding to a series of positioning signal sources, and estimating the position of each signal source based on the satellite force data. The mobile station can determine an available signal source based on a predetermined elevation mask.

The positioning signal source can be a GPS SV, and the available SV can be determined by determining the position of the SV relative to the elevation mask. In addition, the available SV can be determined to include the SV whose position at a later time is compared to the elevation mask.

The method for selectively requesting location data may include generating a standard compliant message. The method includes generating a manufacturer-specific location data message requesting satellite ephemeris data. The message can identify the satellite for which the ephemeris data is requested.

One aspect of the apparatus of the present invention is a configuration for selectively requesting GPS satellite ephemeris data from a positioning entity. The device determines a plurality of available GPS SVs based, at least in part, on satellite power storing GPS SV satellite power, ephemeris module storing ephemeris data corresponding to one or more GPS SVs, and satellite power data. It includes the ephemeris update module. The ephemeris update module determines whether valid ephemeris data is stored in the ephemeris module and optionally requests ephemeris data for its GPS SV that does not have valid ephemeris data in the ephemeris module. do.

In another aspect, the method and apparatus of the present invention is the use of a positioning entity comprising satellite force and an ephemeris module. The location entity also includes a location record update module capable of receiving an optional ephemeris request message and in response to the request, transmitting ephemeris data for the GPS satellites identified in the optional request message. .

Brief description of the drawings

These and other aspects, features and advantages of the method and apparatus of the present invention will become apparent upon review of the following detailed description and the accompanying drawings. In the drawings, like reference numerals identify identical or functionally equivalent elements.

1 is a functional block diagram of a wireless communication system with position determination capability.

2 is a flowchart of a method for selectively updating ephemeris data.

3 is a table illustrating fields in an optional ephemeris request message.

Detailed Description of the Preferred Embodiments

One embodiment of the method and apparatus of the present invention updates an SV ephemeris in a mobile station that communicates with a wireless communication system. The mobile station determines a number of GPS SVs theoretically available for positioning. The mobile station determines if it has already received satellite ephemeris for the available SV. The mobile station also determines whether the satellite ephemeris is valid over a predetermined time period. The mobile station may generate a standards compliant ephemeris request that selectively requests ephemeris for that SV for which there is no valid ephemeris data. In addition, the mobile station can optionally request an ephemeris for that SV whose ephemeris data will not be valid over a predetermined time period. This prevents the mobile station from repeatedly downloading already received ephemeris data and prevents the mobile station from downloading ephemeris data for SVs that are unlikely to be available for positioning.

1 is a functional block diagram of a wireless communication system 100. The wireless communication system 100 can be a wireless telephone system with location capability. For example, the wireless communication system 100 may include Telecommunications Industry Association (TIA) / Electronics Industries Alliance (EIA) -95-B, MOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL MODE SPREAD SPECTRUM SYSTEMS or TIA / EIA / IS-2000 -5, UPPER LAYER (LAYER 3) SIGNALING STANDARD FOR cdma2000 may be a code division multiple access (CDMA) wireless system according to TIA / EIA / IS-2000 including SPREAD SPECTRUM SYSTEMS. In addition, the position measurement capability of the wireless communication system 100 can operate according to, for example, TIA / EIA IS-801, POSITION DETERMINATION SERVICE STANDARDS FOR DUAL MODE SPREAD SPECTRUM SYSTEMS. Of course, although the wireless communication system 100 is described as a wireless CDMA telephone system, the wireless communication system 100 need not be a CDMA system, and the wireless communication system 100 need not be a telephone system. Still other systems include, for example, wireless positioning systems, Bluetooth communication systems, Institute of Electrical and Electronics Engineers (IEEE) 802.11 compliant wireless networks, wireless dispatch systems, wireless radio systems, or other means for communication. can do.

The wireless communication system 100, in turn, includes a mobile station switching center (MSC) 120 in communication with a base transceiver system (BTS) 110 in communication with a mobile station 140. The MSC 120 also communicates with a positioning entity (PDE) 130. Although only one MSC 120, BTS 110, mobile station 140, and PDE 130 are shown in system 100, system 100 may have a plurality of respective elements, and BTS ( The number of 110 or mobile stations 140 need not be provided, for example, in any particular ratio or numerical relationship.

Alternatively, mobile station 140 may be a terminal, remote station, user equipment (UE), access terminal, wireless telephone, cellular telephone, handset, mobile device, mobile unit, personal digital assistant (PDA), computer, or the like. Or other means for. The mobile station 140 does not necessarily need to move and may be fixed. However, the need for positioning capability is greatly reduced for fixed terminals that rarely change position.

Mobile station 140 includes a transceiver 142, which may be an RF wireless transceiver. The transceiver 142 causes the mobile station 140 to receive the forward link signal from the base station 110. Also, transceiver 142 typically causes the mobile station to transmit a reverse link signal to base station 110. In addition, the transceiver 142 may be configured to receive a signal from a positioning system. The transceiver 142 may be configured to receive a signal, for example, from a GPS satellite vehicle (SV).

Typically, the transceiver 142 converts the forward link signal received by the mobile station 140 into a baseband signal. The baseband signal may be data such as location information.

Processor 152 may be coupled to transceiver 142 to process received data, and may also perform functions related to transceiver 142. Processor 152 is coupled to memory 154. The processor 152 can store and access data in the memory 154. In addition, the processor 152 may operate according to processor readable instructions stored in the memory 154.

Mobile station 140 also includes a clock 144 that can track time against a time standard. For example, clock 144 can be used to track GPS time, CDMA system time, or Universal Coordinated Time (UTC). Clock 144 may be used to determine the arrival time of a forward link signal, such as, for example, a forward link pilot signal.

Mobile station 140 also includes satellite force 146, which is a series of data that typically indicates the position of the GPS SV constellation. The mobile station 140 can approximate the location of each GPS SV using satellite power information. Mobile station 140 may use the information stored in satellite force 146 along with GPS time information from clock 144 to predict the availability of GPS SV. Each GPS SV periodically transmits satellite force data. Mobile station 140 may directly receive satellite force data by receiving and decoding GPS SV transmissions. However, as noted above, the data rate from the GPS SV may be lower than the data rate that can be achieved through the wireless communication system 100. Thus, alternatively, mobile station 140 can receive data for satellite force 146 from PDE 130 in wireless communication system 100. For example, mobile station 140 may download satellite force data from PDE 130 and store that data in satellite force 146. Alternatively, satellite force 146 may be implemented in memory 154, and the mobile station may store satellite force data in a portion of memory 154.

Satellite force 146 includes data that approximate the location of each SV. Ephemeris data is used to extend satellite force data to provide accurate determination of the location of a particular SV. The mobile station 140 includes an ephemeris module 148 coupled to the transceiver 142 and the processor 152 to store ephemeris data. Similar to satellite force data, mobile station 140 may receive ephemeris data directly from GPS SV and store that data in ephemeris module 148. The ephemeris module 148 may be implemented as part of the memory 154.

Alternatively, mobile station 140 may receive ephemeris data from PDE 130 via base station 110. As described in more detail below, mobile station 140 may optionally request ephemeris data for its SV that is determined to be available. The mobile station's ability to selectively request ephemeris data minimizes the amount of ephemeris data transmitted. In addition, the combination of satellite force 146 and ephemeris module 148 at mobile station 140 may not communicate with PDE 130 if mobile station 140 is outside the coverage area of base station 110 or otherwise. If not, have the mobile station 140 calculate its location independently.

Mobile station 140 also includes an ephemeris update module 150. The ephemeris data sent by the SV contains the "Time of ephemeris" field t _oe . The time of Ipemaris is a time stamp indicating the midpoint of the epemaris validity. Although, in extreme cases, Ephemeris data may be valid for up to 6 hours, Ephemeris data is typically valid for 4 hours. Thus, typically, Efemeris data is valid for a period of 2 hours before the time of Efemeris and 2 hours after the time of Ephemeris.

The ephemeris update module 150 periodically validates the validity data. For example, the ephemeris update module 150 may validate the ephemeris data at predetermined time intervals, such as every 10 minutes. Alternatively, the ephemeris update module 150 may validate the ephemeris data at some occurrence, such as an outgoing or incoming telephone call. In another embodiment, the ephemeris update module 150 may validate the ephemeris data according to algorithms that may generate fixed, random, or pseudorandom verification and update intervals.

During the verification process, the ephemeris update module 150 accesses the data in the satellite force 146 to determine whether the SV is likely to exceed a predetermined elevation mask. For example, elevation masks may be used to screen SVs that may be unavailable. Unavailable SVs may include those SVs that are below or very close to the prediction limit. Thus, a zero degree elevation mask may be used by the ephemeris update module 150 to determine which SV exceeds the prediction limit.

Also, the ephemeris update module 150 may use any independent time that may be stored, for example, in the memory 154. Independence time represents the duration during which the mobile station 140 should be able to accurately determine its location independent of support from the PDE 130. The independent time can be, for example, 30 minutes or 60 minutes.

In addition, the ephemeris update module 150 determines which SV will exceed the elevation mask at a future time equal to the current time plus independent time. Thus, the ephemeris update module determines which of the SVs are available by determining which SV currently exceeds the elevation mask and which SV will exceed that elevation mask after independence.

The ephemeris update module 150 accesses the ephemeris module 148 to determine if ephemeris data is available for any identified available SV. If valid ephemeris data is not available for any identified SV, ephemeris update module 150 generates a request for ephemeris data sent to PDE 130. If valid ephemeris data is available for SV but becomes invalid prior to the expiration of the independent time, ephemeris update module 150 generates a request for ephemeris data for that SV. The ephemeris update module 150 may determine that ephemeris data is invalid for SV if more than 120 minutes have elapsed since the ephemeris time associated with the data.

One embodiment of the algorithm performed by the ephemeris update module 150 can be summarized with the following pseudocode.

Mobile station 140 communicates with base station 110. Base station 110 may be, for example, a BTS, an access point, a central dispatch, or the like, or other centralization means for communication. Typically, the communication link between base station 110 and mobile station 140 is a wireless link. Base station 110 transmits the requested ephemeris and satellite power data from PDE 130 to mobile station 140 via one or more forward link channels. Mobile station 140 transmits a request for satellite power and ephemeris data to base station 110 over one or more reverse link channels. Base station 110 forwards the request to PDE 130. Base station 110 may be, for example, a wireless telephone base station that is compatible with a wireless communication standard such as TIA / EIA-95-B or TIA / EIA / IS-2000.

Base station 110 communicates with a mobile station switching center (MSC) 120 that serves as an interface between a wireless communication system 100 and an external communication system, such as a public switching telephone network (PSTN), not shown. Alternatively or additionally, MSC 120 may provide an interface between a data network, such as the Internet, and wireless communication system 100.

MSC 120 also communicates with PDE 130. The link between PDE 130 and MSC 120 may be a wireless link or a wired link. Also, although PDE 130 is shown to be coupled with MSC 120, PDE 130 may be coupled to base station 110, and the communication link between PDE 130 and MSC 120 may be a base station. May occur through 110. In addition, other configurations are possible. PDE 130 includes satellite force 132, ephemeris 134, location record update module 136, and location determination module 138.

PDE 130 may be used to determine the location of mobile station 140 based in part on information provided by mobile station 140. For example, mobile station 140 may determine pseudoranges for multiple location determination sources, such as GPS satellites, and transmit the pseudorange information to PDE 130. The PDE may then determine the location of the mobile station 140 in the location determination module 138.

PDE 130 also communicates with a location determination source. For example, the PDE 130 may include a GPS receiver (not shown) to receive satellite power and ephemeris data from the GPS SV. PDE 130 may then store the SV data in satellite force 132 and ephemeris 134. Since the PDE 130 can communicate almost continuously with the SV, the satellite force 132 and the Ipemeris 134 in the PDE 130 are likely to contain the most current data. Also, typically, PDE 130 may deliver satellite force 132 and ephemeris 134 data to mobile station 140 at a data rate greater than the rate used by SV. Thus, the mobile station may obtain satellite power and ephemeris data from PDE 130 more quickly than searching, acquiring and downloading data from the SV. Of course, the satellite force 132 need not be limited to the SV data, but may alternatively include positioning information for another positioning signal source called pseudo-lites. Pseudo-lights may include, for example, differential GPS positioning sources, or other positioning beacons or sources.

The location record update module 136 may be configured to receive an optional data or record request from the mobile station 140. Based on the request, the location record update module 136 can determine the SV ephemeris data requested by the mobile station 140. The location record update module 136 can then access the ephemeris 134 and retrieve at least a portion of the ephemeris data requested by the mobile station 140. The location record update module can then generate a message with the requested data and send the message to the mobile station 140. In one embodiment, the location record update module 136 retrieves all ephemeris 134 data, and cuts the data so that ephemeris for any SV for which the mobile station 140 does not have the requested data. Exclude data.

One embodiment of an ephemeris update method 200 performed in a mobile station 140 is shown in FIG. 2. The method 200 may be performed by, for example, the mobile station 140 in the wireless communication system 100 of FIG. 1. The method 200 begins at block 202 where the mobile station initially requests satellite force data. The mobile station may send a satellite power data request message to the PDE. The mobile station may periodically request satellite force data or may request satellite force data when an event occurs. For example, a mobile station may request satellite force data each time the mobile station is commanded to enter a positioning mode or at power-up.

The mobile station then proceeds to block 204 waiting to receive satellite force data. The mobile station may receive satellite force data from the PDE or may receive other indications to cause the mobile station to repeat the request for satellite force data.

Once satellite power data is received, the mobile station proceeds to decision block 210 to determine whether the mobile station is in a positioning mode. The location measurement mode may be one or more modes of operation in which the mobile station periodically updates the ephemeris to allow relatively fast location fixes. For example, the positioning mode may include a tracking mode in which the mobile station periodically performs positioning. For example, in tracking mode, the mobile station may determine a fix every 10 minutes. The location measurement mode may also include a stay warm mode in which the mobile station updates the ephemeris data to allow accurate location fixes without delays associated with satellite power and ephemeris downloads.

If the mobile station is not in the positioning mode, the mobile station may be powered down or the positioning capability may be turned off. In this case, the mobile station proceeds to block 260 where the method ends.

If the mobile station is in the positioning mode, the mobile station proceeds to block 222 where the mobile station determines the position of the SV. The mobile station can, for example, use satellite force data to predict the approximate location of the SV. After determining the SV location, the mobile station proceeds to block 224 where the mobile station determines which of the SVs is theoretically available based at least in part on the location. Since the mobile station may not know its exact location or the type of terrain near that mobile station, and therefore may not know which of the SVs is below the limit, the mobile station's determination of the availability of the SV is only theoretical. In addition, the mobile station may not be able to determine if signals from one or more of the SVs are blocked or otherwise unavailable.

The mobile station may determine the availability of the SV based on an approximate estimate of the mobile station location, in combination with the elevation mask. The approximate estimate of the mobile station location may be derived, for example, based on the previous location fix, or may be based on the location of the base station or repeater with which the mobile station communicates. An elevation mask may be used to exclude the SV that is not within the mask's parameters. For example, only those SVs that are expected to be above a limit or other elevation may be determined to be available by the mobile station.

After determining the available SVs, the mobile station proceeds to decision block 230 where the mobile station determines whether stored ephemeris data for the available SVs is valid. The mobile station compares the " times of ephemeris " associated with the ephemeris data to determine if the ephemeris data is currently valid and further determines whether the ephemeris will be valid for a predetermined time, i.e. independence_time. It can also be determined. independence_time may be, for example, 20, 30, 45, or 60 minutes, or some other time increment. Typically, independence_time is less than 120 minutes. If Ipemeris is valid for all available SVs, the mobile station proceeds to block 260 and terminates the method.

However, if the ephemeris is not currently valid or expires before independence_time, the mobile proceeds to block 240 requesting ephemeris for the SV for which the data is invalid or invalid. The mobile station, for example, generates a standards-compliant request that selectively requests the desired ephemeris data. The mobile station may then send the request to the PDE.

The mobile station then proceeds to decision block 250 to determine whether valid ephemeris data has been received. The mobile station may perform the verification when a message is received from the PDE, or may perform the verification at a predetermined time-out period after sending the request.

The mobile station may request ephemeris data from the PDE, but may not receive the data. This may occur, for example, if the PDE transmits SV ephemeris data for a subset of the requested SV. Alternatively, if the PDE sends a reject message to the mobile station, the mobile station may not receive the requested ephemeris data. For example, if the SV is below the limit and the PDE lacks the current Iphemeris or the SV is not good, the PDE may not give Ephemeris data to the mobile station.

If a valid ephemeris has been received by the mobile station for all requested SVs, the mobile station proceeds to block 260 to end method 200. Alternatively, if the mobile station did not receive valid ephemeris data for one or more requested SVs, the mobile station proceeds to block 252.

In block 252, the mobile waits for a predetermined waiting period and then re-requests ephemeris data for the SV for which no valid ephemeris has been received. The predetermined waiting period may be approximately one second, several seconds, or one minute.

The mobile station then returns to block 240 to re-request the ephemeris data that has not been successfully received previously. If the PDE reports that one of the SVs is not good, the mobile station may re-request the ephemeris data associated with the bad SV only if the mobile station is requesting other SV ephemeris data. An optional ephemeris request message may be such that a request of ephemeris data for more than one SV does not consume any additional bandwidth when compared to a request of ephemeris data for a single SV. Of course, typically, the bandwidth required for the base station to transmit multiple SV ephemeris is greater than the bandwidth required for transmitting ephemeris data for a single SV.

Another embodiment of the method 200 is contemplated. For example, once the mobile station has successfully received satellite force data, the mobile station may periodically check to see if it is in a positioning mode and update the ephemeris data for the available SV. The mobile station may, for example, determine the available SV and update the ephemeris data every 10 minutes.

In another embodiment, at block 222, the mobile station may initially determine all satellite locations for a predetermined number of intervals starting at the current time. The predetermined number of times may be sufficient to ask the mobile station to determine the SV location by at least the time into the future of independence_time. Also, at the next ephemeris update interval, the mobile station needs to determine the SV location only for the time into the future of independence_time.

3 is a table illustrating some of the fields in an optional ephemeris request message. The mobile station may be configured to generate an optional ephemeris request message that is compatible with the current standard. For example, the optional Ephemeris request message may be compatible with TIA / EIA / IS-801.

The TIA / EIA / IS-801 standard defines a positioning data message (PDDM) 300 that can be transmitted by a mobile station. PDDM 300 includes a Location Message Type field, that is, PD_MSG_TYPE 310, that identifies the type of Location Data message. The length of the field is 8 bits. The default value for that field is 0X00, where the prefix "OX" represents a hexadecimal number. However, the standard provides for manufacturer-specific PDDM definitions. For example, the OXCO value may indicate a manufacturer proprietary message.

The REQ_TYPE 320 field identifies the type of data requested by the mobile station. A REQ_TYPE value of "1001" indicates that a GPS ephemeris is requested. However, if this REQ_TYPE is used with the predetermined manufacturer ownership PD_MSG_TYPE value identified above, the message may indicate that the request is an optional SV ephemeris request message. The message may indicate the SV-specific ephemeris requested in the REQ_PAR_RECORD 340 field of PDDM 300.

The REQ_PAR_RECORD 340 field has a length of 40 bits. A value of 40 bits represents the requested SV emelis. The REQ_PAR_RECORD 340 field includes an AB_PAR_REQ 342, a sub-field including an SV_MASK 344, and a spare 346 field.

The AB_PAR_REQ 342 sub-field is only 1 bit long and indicates whether the mobile station is requesting an alpha / beta parameter. If an alpha / beta parameter is requested, the mobile station sets the field to '1', otherwise the mobile station sets the field to '0'.

<< provides definition of alpha / beta parameter >>

The SV_MASK 344 sub-field is 32 bits long. The value of that sub-field identifies the subset of GPS satellites for which ephemeris is requested. For example, a bit significant LSB (least significant bit) may represent SV 1, and bit 31 MSB may represent SV 32. In one embodiment, the bit value of '1' represents the data for which SV was requested.

In addition, the REQ_PAR_RECORD 340 field contains 7 bits that are reserved (346). The reserved bits allow for later definition and expansion. The mobile station may set the spare 346 bit to "0000000". The reserved bits may be added to the SV_MASK 344 sub-field, for example, if there is a source other than the GPS SV for which Ephemeris data is available.

A PDE that receives an optional ephemeris request message may respond with an undesired provision of a GPS ephemeris message. However, in the response message, the PDE may cut data for any SV not requested in the SV_MASK 344 sub-field of the PDDM 300 message.

As such, a method and apparatus for selectively updating ephemeris data in a mobile station has been described. One method allows a mobile station to selectively request and receive ephemeris data. Selective request and transmission of ephemeris data allows for optimization of the communication bandwidth between the mobile station and the base station, since repetitive ephemeris data as well as data for unavailable SVs are excluded from the communication message.

Thus, the mobile station can download ephemeris data for the available SV and determine its location separately from the communication link with the system. The optional ephemeris request is configured to be compatible with existing standards, thus allowing the method and apparatus to be implemented in conventional systems.

Although the method and apparatus have been described with respect to a wireless telephone system, in particular a CDMA telephone system utilizing GPS satellites for location determination, the method and apparatus may be implemented in other types of systems. SV is not limited to GPS SV and does not require satellites, but may be any type of positioning signal source whose source location changes. For example, the satellite may be a Global Orbiting Navigation Satellite System (GLONASS) satellite vehicle.

 Electrical connections, couplings, and connections have been described with respect to various devices or elements. The connection and coupling may be direct or indirect. The connection between the first device and the second device may be a direct connection or an indirect connection. The indirect connection may include an intervening element that may process a signal from the first device to the second device.

Signals or processes have been described with respect to various processes, methods, or flowcharts. The flow from one step or block to the next step or block may be direct or indirect. The indirect connection may include an intervening block that may process a signal from one block before the next block. In addition, the arrangement of blocks or steps shown in the drawings does not necessarily need to be an indication of order. In some cases, blocks, processes, steps, or methods may be rearranged without affecting the results of the process or method.

Those skilled in the art will appreciate that various different techniques and techniques may be used to represent information and signals. For example, data, commands, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may include voltage, current, electromagnetic waves, magnetic or magnetic particles, photons or photons, Or a combination thereof.

In addition, one of ordinary skill in the art may recognize that the various exemplary logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented in electronic hardware, computer software, or a combination thereof. . To clearly illustrate this alternative possibility of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above primarily in terms of their functionality. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but they should not be interpreted as causing a determination of such implementation to be outside the scope of the methods and apparatus of the present invention.

The various illustrative logical blocks, modules, circuits described in connection with the embodiments disclosed herein may be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate array signals (FPGAs), or Other programmable logic devices, separate gate or transistor logic, separate hardware components, or any combination thereof designed to perform the functions described herein may be implemented or performed. A general purpose processor may be a microprocessor, but in other ways, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, eg, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be implemented directly in hardware executed by a processor, a software module, or a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, which can read information from and write information to the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside within an ASIC.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Those skilled in the art will clearly appreciate various modifications to these embodiments, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (23)

A method of selectively requesting location data, Determining, at the mobile station, a plurality of available positioning signal sources from the series of positioning signal sources; Determining whether current positioning data associated with the plurality of available positioning signal sources is valid; And Selectively requesting positioning data associated with the plurality of positioning signal sources for which current positioning data is invalid. The method of claim 1, Determining the plurality of available positioning signal sources, Receiving satellite force of positioning data corresponding to the series of positioning signal sources; Estimating the position of each signal source in the series of positioning signal sources; And Determining the plurality of available positioning signal sources based at least in part on an elevation mask. The method of claim 1, Determining the plurality of available positioning signal sources, Estimating a position of each of the plurality of GPS satellite aircraft based in part on the satellite force of the GPS satellite vehicle position data; And Determining a plurality of available GPS satellite aircraft based in part on the position and elevation mask of each of the plurality of GPS satellite vehicles. The method of claim 3, wherein Determining the plurality of available positioning signal sources, Estimating a location of each of the plurality of GPS satellites at a predetermined future time; And Determining a plurality of available GPS satellites based in part on the position of each of the plurality of GPS satellites and the elevation mask at the predetermined future time. The method of claim 1, Determining the plurality of available positioning signal sources, Comparing the position of the plurality of GPS satellites with an elevation mask; And Determining a plurality of available GPS satellites whose satellite positions correspond to the elevation masks. The method of claim 1, Determining validity of positioning data associated with the plurality of positioning signal sources, Retrieving the time of Ipemeris associated with each of the series of available GPS satellites; And Determining validity of the positioning data based at least in part on the time of the ephemeris and a predetermined position independent time. The method of claim 1, Determining validity of positioning data associated with the plurality of positioning signal sources, Determining the validity of the GPS satellite air vehicle emelis at a predetermined independent time in the future. The method of claim 1, Selectively requesting the positioning data, Requesting satellite ephemeris data from a positioning entity (PDE) of an available GPS satellite, for an available GPS satellite for which satellite ephemeris data is invalid. The method of claim 1, Selectively requesting the positioning data, Generating a manufacturer-specific location data message (PDDM); In the manufacturer-specific PDDM, identifying a request for satellite ephemeris; And In the manufacturer-specific PDDM, identifying a satellite for which ephemeris data has been requested. The method of claim 1, And wherein said mobile station is selected from a wireless telephone, an access terminal, a computer, and a personal digital assistant (PDA). A method for selectively requesting GPS satellite ephemeris data by a mobile station in a wireless communication system, At the mobile station, determining a location of a GPS satellite; Determining an available GPS satellite based in part on the GPS satellite's position and elevation mask; Determining whether ephemeris data for the available GPS satellites is invalid; And Requesting ephemeris data corresponding to the available GPS satellite from which the ephemeris data is determined to be invalid from a positioning entity (PDE) in the wireless communication system. Request method. The method of claim 11, The requesting the ephemeris data, Generating a location data message (PDDM) for selectively requesting ephemeris data; And Transmitting the PDDM from the mobile station to a base station in communication with the PDE. As a method of providing ephemeris data, Receiving a manufacturer-specific location data message (PDDM) from a mobile station in a wireless communication system; Determining if the manufacturer-specific PDDM includes an optional ephemeris request message; Reducing the series of ephemeris data to produce satellite-specific ephemeris data; And Transmitting the satellite-specific ephemeris data to the mobile station. The method of claim 13, The step of reducing the series of ephemeris data, Comparing the satellite aircraft mask included in the optional ephemeris request message with the series of ephemeris data; And Excluding efemeris data corresponding to a satellite vehicle not identified in said optional ephemeris request message. At least one processor readable storage device containing processor readable code having programmed at least one processor for performing a method for selectively requesting GPS satellite ephemeris data by a mobile station in a wireless communication system, comprising: The method, At the mobile station, determining a location of a GPS satellite; Determining an available GPS satellite based in part on the position and elevation mask of the GPS satellite; Determining whether ephemeris data for the available GPS satellites is invalid; And Requesting ephemeris data corresponding to the available GPS satellite from which the ephemeris data is determined to be invalid from a positioning entity (PDE) in the wireless communication system. At least one processor readable storage device containing processor readable code having programmed one or more processors to perform a method of providing ephemeris data, the method comprising: The method, Receiving a manufacturer-specific location data message (PDDM) from a mobile station in a wireless communication system; Determining if the manufacturer-specific PDDM includes an optional ephemeris request message; Reducing the series of ephemeris data to produce satellite-specific ephemeris data; And Transmitting the satellite-specific ephemeris data to the mobile station. A device configured to selectively request GPS satellite aircraft ephemeris data from a positioning entity (PDE) in a wireless communication system Satellite force configured to store GPS satellite vehicle satellite force data; An ephemeris module configured to store ephemeris data corresponding to one or more GPS satellites; And Communicate with the satellite force and the ephemeris module, determine a plurality of available GPS satellites based at least in part on the satellite force data, and the valid ephemeris data corresponding to the plurality of available GPS satellites is the ephemeris. Determine whether it is stored in a mobile station module, and configured to generate an optional ephemeris request requesting ephemeris data for the available GPS satellites for which valid ephemeris data is not stored in the ephemeris module. A request device for GPS satellite air vehicle ephemeris data, comprising: an update module. The method of claim 17, And a transceiver configured to wirelessly send an optional ephemeris request message to the PDE and to receive ephemeris data from the PDE. The method of claim 17, Further has a clock synchronized to the system time, The ephemeris update module determines a valid ephemeris data based in part on the ephemeris time and the system time associated with each ephemeris data stored in the ephemeris module. Request device for satellite aircraft ephemeris data. The method of claim 17, And the device comprises an application specific integrated circuit (ASIC). The method of claim 17, And the device comprises a cordless telephone. As a positioning entity (PDE) in a wireless communication system, Satellite force configured to store GPS satellite satellite force data; An ephemeris module configured to store GPS satellite ephemeris data; And Communicate with the satellite power and the ephemeris module, receive an optional ephemeris request message from a mobile station, determine one or more GPS satellites for which ephemeris data is requested, and In response, a location record update module, configured to transmit the ephemeris data for the one or more GPS satellites to the mobile station while excluding the ephemeris data for at least one GPS satellite for which no ephemeris data is requested. And a positioning entity. The method of claim 22, The location record updating module is further configured to reduce the ephemeris data stored in the ephemeris module before transmitting the ephemeris data for the one or more GPS satellites.

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