(12)
`
`United States Patent
`Krasner
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,208,290 B1
`Mar. 27, 2001
`
`US006208290B1
`
`(54) GPS RECEIVER UTILIZINGA
`COMMUNICATION LINK
`
`2308033
`WO9714049
`
`11/1997 (GB) .
`4/1994 (W0) ~
`
`(75) Inventor: Norman F. Krasner, San Carlos, CA
`
`
`
`WO9428434 “709615636
`
`
`
`12/1994 5/1996 (W0) -
`
`(US)
`
`OTHER PUBLICATIONS
`
`(73) Assignee: SnapTrack, Inc., San Jose, CA (US)
`
`(*) NOIiCeI
`
`Subject I0 any disclaimer, the term Of this
`patent is extended or adjusted under 35
`U50 154(1)) by 0 days-
`
`(21) Appl, N()_j 08/842,559
`
`(22) Filed:
`
`Apr‘ 15’ 1997
`Related US‘ Application Data
`
`(63) Continuation-in-part of application No. 08/759,523, ?led on
`Dec. 4, 1996, now Pat. NO. 5,841,396, and a continuation-
`in-part of application No. 08/612,582, ?led on Mar. 8, 1996,
`now Pat. No. 5,874,914.
`
`
`
`Int. (:1.7 ............................. .. (52) US. Cl. .............................. .. 342/357.05; 342/357.09;
`342/357.1; 701/213
`(58) Field Of Search ....................... .. 342/35705, 357.09,
`342/3571, 457; 701 /213
`
`(56)
`
`References Cited
`
`4,445,118
`4,457,006
`
`U'S' PATENT DOCUMENTS
`4/1984 Taylor et al. ...................... .. 343/357
`6/1984 Maine .................................. .. 375/87
`_
`_
`(Llst Con?rmed on next page‘)
`FOREIGN PATENT DOCUMENTS
`
`12/1994 (DE) -
`4424412
`4/1991 (EP) '
`0444738
`9/1991 (EP) '
`449798A2
`0512789 A2 11/1992 (EP) .
`545636A1
`6/1993 (B1))‘
`0604404 A2
`6/1994 (EP) _
`
`2264837
`2273218
`
`9/1993 (GB) .
`6/1994 (GB) .
`
`PCT International Search Report sent Jul. 11, 1997.
`“RTCM Recommended Standards for Differential Navstar
`GPS Service” Ver. 2.0 Radio Technical Commission for
`Maritime Services, Jan 1, 199()_
`“Animal—borne GPS: Tracking the Habitat” Rogers &
`Anson, GPS World, pp. 21, 22, Jul. 1994.
`“Navstar GPS User Equipment, Introduction”, NATO Feb.
`1991.
`“Naviatation Journal of the Institute of Navigation” vol. 25,
`No. 2. The Institute of Navigation, 1978 (entire edition).
`(List continued on next page.)
`_
`_
`Primary Exammer—The0d0re M- Blurn
`(74) Attorney, A gent, 0r Firm—Blakely, Sokoloff, Taylor &
`Zafman
`
`Methods and apparatuses for deriving an approximate Dop
`pler for a satellite positioning system (SP5) receiver from an
`approximate location Which is obtained from a cellular
`communication system information source. In one
`embodiment, an approximate location of the SPS receiver is
`derived from the information source and this approximation
`location is used to determine approximate Dopplers to a
`plurality of SP5 Satellites at a given time The approximate
`Dopplers are then used to reduce processing time in either
`determining pseudoranges to the SPS satellites or acquiring
`signals from the SPS satellites. In another aspect of the
`invention, a reference signal is used to provide a local
`oscillator signal Which is used to acquire SPS signals in an
`SPS receiver. This reference signal is extracted from a data
`signal modulated on a carrier frequency. The data signal on
`the carrier fre uenc is transmitted from in one exam le a
`.
`q.
`y .
`.
`.
`’.
`.
`p ’
`Wireless cell site WhlCh is communicating With the SPS
`receiver WhlCh has a cellular based communication receiver.
`
`71 Claims, 15 Drawing Sheets
`
`GPS
`Antenna
`
`411
`(
`Analog to
`Digital
`Converter
`
`409
`Comm.
`Antenna 6P5 L-Q'S
`
`403
`
`4116
`( 413
`Analo to
`Comm.Signals
`FlFtolF —> Digltgal
`Convener
`Convener
`T415
`Comm.
`Signals L.O.'s
`
`417
`
`418
`
`420
`
`Digital
`Memory
`
`Processor
`
`Frequency
`Synthesizer
`
`Transm
`it
`Power
`Control
`
`Transmit /
`Receive
`Switch
`
`433
`
`IF to RF
`Converter
`P 426
`
`Apple, Inc. Exhibit 1038 Page 1
`
`

`
`US 6,208,290 B1
`Page 2
`
`US. PATENT DOCUMENTS
`
`7/1986 Kilvington ......................... .. 364/602
`10/1987 Jasper - - - - - - - - - -
`- - - -- 375/1
`
`- - - -- 375/1
`11/1988 Jane 51 a1~ - - - - - -
`. 342/352
`1/1989 MacDoran et a1.
`. 342/418
`9/1990 Kumar ......... ..
`. 342/352
`3/1991 Ma et a1.
`. 342/357
`8/1991 Darnell et a1.
`_ 342/357
`6/1992 Barnard _____ __
`10/1992 Alves, Jr. ........................... .. 342/352
`4/1993 Geier .................................. .. 364/449
`6/1993 Mansell ct a1~
`- 342/357
`7/1993 Brown et a1‘ "
`' 342/357
`9/1993 Averbuch
`' 375/108
`12/1993 Abaunza .
`375/1
`
`5,448,773
`5,483,549
`574917486
`5,515,062
`
`9/1995 McBurney et a1. ................ .. 455/343
`1/1996 Weinberg et a1. ..
`375/200
`2/1996 Welles’ H et aL
`342/357
`5/1996 Maine et a1.
`342/457
`
`5,519,760
`5/1996 Borkowski et a1. ................. .. 379/59
`579137170 * 6/1999 Wortham_
`
`OTHER PUBLICATIONS
`
`“GPS Receiver Structures for the Urban Canyon” Petterson
`et al., ION—GPS—95, Session C4, Land Vehicular Applica
`tions, Palm Springs, CA Sep, 1995,
`Raab et al., “An Application of the Global Positioning
`System to Search and Rescue and Remote Tracking”, Navi
`ation “Journal of Institute of Navi ation” vol 24 No 3
`g
`g
`'
`’
`'
`’
`
`1977~
`_
`_
`5/1994 Brown ....... ..
`. 342/357
`Davenport, Robert G- “FFT Processlng 0f Dlrect SequenCe
`5/1994 Kennedy et a1. .................. .. 342/457
`Spreading Codes~ -
`- ” IEEE 1991- National Aerospace and
`6/1994 Maki .................................. .. 342/357
`Electronics Conference NAECON 1991, vol. 1 pp. 98—105,
`6/1994 Mueller et a1
`. 364/449
`May 1991.
`11/1994 Dennis ............. ..
`. 364/449
`PCT International Search Report sent on Mar. 10, 1997.
`1/1994 Schuchman et al- -
`- 364/449
`PCT International Search Report sent on Feb. 21, 1997.
`1/1995 Yokev et a1‘
`' 342/457
`.
`1/1995 Brown et a1. ..
`. 364/449
`PCT Internanonal Search Report Sent on May 13> 1997
`1/1995 Fernandes et a1. .................... .. 375/1
`5/1995 Attwood ............................. .. 342/357 US Patent Application Serial No. 08/759,523, ?led D90 4,
`5/1995 Gilhousen et a1.
`. 375/705
`1996 and entitled “An Improved GPS Receiver UtilitZing a
`5/1995 Johnson ----------- --
`- 342/357
`Cornrnunication Link”, 47 pages and 14 sheets of draWings.
`5/1995 SWensen et a1.
`. 375/200
`7/1995 Yokev et a1. ...................... .. 375/202
`
`* cited by examiner
`
`4,601,005
`4,701,934
`
`4,785,463
`4,797,677
`4,959,656
`4,998,111
`5,043,736
`5,119,102
`5,153,598
`5,202,829
`572237844
`532253842
`5’245’634
`5,271,034
`
`5,311,194
`5,317,323
`5,323,163
`5,323,322
`5,365,447
`573657450
`5’379’O47
`5,379,224
`5,379,320
`5,412,388
`5,416,797
`5,420,592
`5,420,883
`5,430,759
`
`Apple, Inc. Exhibit 1038 Page 2
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 1 of 15
`
`US 6,208,290 B1
`
`Mobile
`
`GPS
`Receiver 1
`
`GPS
`Receiver 2
`
`Mobile
`GPS
`Receiver 3
`
`Cellular
`Switching
`Center
`
`GPS Server
`(with Server
`Phone No.)
`
`cellular
`Switching
`Center
`
`Query
`Terminal
`
`Apple, Inc. Exhibit 1038 Page 3
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 2 0f 15
`
`US 6,208,290 B1
`
`Obtain Approximate Position of Cell Site
`(and Consequently Objects within Cell \/ 40
`Serviced by Cell Site) from a Cellular
`Based Information Source
`
`l
`
`Determine Approximate Dopplers to a
`Plurality of Satellites in View of the A 42
`Approximate Position
`
`l
`
`Use Approximate Dopplers in a Mobile
`SPS Receiver
`(e.g., Use Approximate Dopplers to V 44
`Determine Pseudorange or Use to
`Acquire SPS Signals from in View
`Satellites)
`
`FIG. 2
`
`Apple, Inc. Exhibit 1038 Page 4
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 3 0f 15
`
`US 6,208,290 B1
`
`Cellular Based Communication System (with
`SP8 Receiver) Transmits Position Request to \J 50
`Cellular Cell Site
`
`tr
`Cell Site Determines Cell Site Location or
`Cell-Site Identity (or Obtains Either from a
`Cellular Switching Center) or Service Area
`Containing Cell Site
`
`A52
`
`V
`
`Cell Site Transmits Cell Site Location or
`Cell Site Identity to Cellular Based
`Communication System
`
`\—~ 54
`
`V
`Cellular Based Communication System
`Transmits the Cell Site Location
`(or Cell Site Identity) to an SPS Server
`Through the Cell Site
`
`’\ 56
`
`V
`SPS Server Determines a Plurality of Approx
`imate Dopplers to a Corresponding Plurality of
`Satellites in View of the Cell Site from Either \_, 58
`the Cell Site Location or from the Cell Site
`Identity (and Optionally from the Time of Day)
`
`V
`SPS Server Transmits Approximate Dopplers
`to Cellular Based Communication System
`(Through Cell Site)
`
`V
`Cellular Based Communication System Uses
`Approximate Dopplers for its SPS Receiver V 62
`
`FIG. 3A
`
`Apple, Inc. Exhibit 1038 Page 5
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 4 0f 15
`
`US 6,208,290 B1
`
`Cellular Based Communication System (With SPS
`Receiver) Transmits Position Request to a Cellular -'\ 70
`Cell Site
`
`7
`
`Cell Site Determines Cell Site Location or Cell Site
`identity (or Obtains Either from a Cellular
`Switching Center)
`
`\/ 72
`
`V
`
`Cell Site Sends Cell Site Location or Cell Site
`identity (and Phone No. or identifier of Cellular
`Based Communication System) to SP8 Server
`Usually Through a Cellular Switching Center A 74
`(if the Cell Site has Neither Site Location nor
`Site identity, This information May Be Requested
`by Cell Site and Forward to the SPS Server
`with the Phone No. or Identifier)
`
`V
`SPS Server Determines Approximate Doppler
`from at Least One of Cell Site Location or Cell A 76
`Site identity or Sevice Area identity or Location
`
`W
`SPS Server Sends Approximate Doppler to Cellular
`Based Communication System (Transmission
`Usually Occurs Through Cellular Switching Center V 78
`and Cell Site)
`
`TV
`
`Cellular Based Communication System Uses
`Approximate Dopplers for its SPS Receiver
`
`,__\ 8O
`
`FIG. 3B
`
`Apple, Inc. Exhibit 1038 Page 6
`
`

`
`U.S. Patent
`
`Mar. 27,2001
`
`Sheet 5 0f 15
`
`US 6,208,290 B1
`
`Cellular Based Communication System (With SPS
`Receiver) Transmits Position Request to Cellular
`Cell Site
`
`Cellular Based Communication System Extracts
`Cell Site Location (e.g., Latitude and Longitude)
`or Cell Site identity from the Cell Site's
`Transmissions (e.g., Trsansmissions Conforming
`to lS-95 CDMA Standards or Similar Standards)
`
`V
`Cellular Based Communication System
`Transmits the Cell Site Location (or Cell Site
`Identity) to an SPS Server Through the Cell Site
`
`V
`SPS Server Determines a Plurality ot Approximate
`Dopplers to a Corresponding Plurality of Satellites
`in View of the Cell Site from Either the Cell Site
`Location or from the Cell Site Identity (and
`Optionally from the Time of Day)
`
`V
`SPS Server Transmits Approximate Dopplers to
`Cellular Based Communication System
`(Through Cell Site)
`
`V
`
`Cellular Based Communication System Uses
`Approximate Dopplers for its SPS Receiver
`
`FIG. 3C
`
`Apple, Inc. Exhibit 1038 Page 7
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 6 0f 15
`
`US 6,208,290 B1
`
`SPS Server Requests Position Fix from a Specific
`Cellular Based Communication System (with an SPS Receiver) f 300
`Which is Specified by a Phone No. or Other Identifier
`
`V
`Position Request is Normally Transmitted Through a Cellular ,\
`Switching Center to One or More Cell Sites
`302
`
`V
`Cell Sites Transmit Position Request (and Perhaps also Cell
`Site ID or Cell Site Location or Service Area Containing
`Cell Site) to Specific Cellular Based Communication System
`
`\/ 304
`
`V
`Specific Cellular Based Communication System Responds
`to a Cell Site Which Communicates with the Specific System;
`Response May include Sending Cell Site ID or Cell Site A 305
`Location or Service Area identity (Containing Cell Site) to
`Server Through the Cell Site
`
`V
`SPS Server Receives information Specifying the Specific
`Cellular Based Communication System and at Least One of
`Cell Site ID or Cell Site Location or Service Area ID; SPS
`Sewer Determines a Plurality of Approximate Dopplers to a A 308
`Corresponding Plurality of Satellites in View of the Cell Site
`from One of the Cell Site ID, the Cell Site Location or the
`Service Area ID [and Optionally (if Database Not Available)
`from the Time of Day]
`ir
`SPS Server Transmits Approximate Dopplers to Cellular
`Based Communication System (Through Cell Site)
`
`‘“ 310
`
`it
`Cellular Based Communication System Uses Approximate A
`Dopplers for its SPS Receiver
`312
`
`FIG. 4A
`
`Apple, Inc. Exhibit 1038 Page 8
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 7 0f 15
`
`US 6,208,290 B1
`
`SPS Sewer Requests Position Fix from a Specific
`Cellular Based Communication System (with an SPS Receiver) f 320
`Which is Specified by a Phone No. or Other Identifier
`
`V
`
`Position Request is Normally Transmitted Through a Cellular ,\ 22
`Switching Center to a plurality of cell sites
`3
`
`V
`Cell Sites Transmit Position Request (and Perhaps also Cell
`Site ID or Cell Site Location or Service Area Containing
`Cell Site) to Specific Cellular Based Communication System
`
`\/ 324
`
`V
`Specific Cellular Based Communication System Responds
`to a Cell Site Which Communicates with the Specific System;
`Response May Include an Acknowledgement Signal Returned
`to the Cell Site Which Then Sends Cell Site ID or Cell Site A 326
`Location or Service Area lD Through Cellular Switching Center
`to SP8 Server
`
`V
`SPS Server Receives information Specifying the Specific
`Cellular Based Communication System and at Least One of
`Cell Site ID or Cell Site Location or Service Area ID; SPS
`Server Determines a Plurality of Approximate Dopplers to a A 328
`Corresponding Plurality of Satellites in View of the Cell Site
`from One of the Cell Site ID, the Cell Site Location or the
`Service Area ID [and Optionally (if Database Not Available)
`from the Time of Day]
`
`V
`SPS Server Transmits Approximate Dopplers to Cellular
`Based Communication System (Through Cell Site)
`
`\" 330
`
`V
`Cellular Based Communication System Uses Approximate A
`Dopplers for its SPS Receiver
`332
`
`FIG. 4B
`
`Apple, Inc. Exhibit 1038 Page 9
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`LI.66_.nS
`
`51f000
`
`US 6,208,290 B1
`
`
`
`
`
`
`
`mosom:o:mE_oE_ummmma_:__mo
`
`8%Vas«mmam.238A5amam5&8mm.83\.Em.83\.E3NEam338E.5am.2385.83\Em.83\.23E2am528E2mm5:58<.83\.23
`
`
`
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`
`aaqoo9mE_xe&<8:80..gm:88:80..5&_mm.<
`
`8_>_¢m.
`
`
`
`$2.8_>._mm
`
`Apple, Inc. Exhibit 1038 Page 10
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 9 0f 15
`
`US 6,208,290 B1
`
`To / From Cellular
`Switching Centers or
`Land Based Phone
`System Switch(es)
`or Cell Site(s)
`
`GPS Signal Source
`(e.g., Network of GPS
`Receivers Providing
`Differential GPS information
`and Providing GPS Signal
`Data
`
`360
`
`362
`
`MODEM or N 353
`Other Interface
`it
`
`MODEM or
`Other Interface ” 354
`A
`
`"
`
`"
`
`|
`o r
`_
`p me x
`* """""""" " * GPS Receiver
`356
`
`>
`
`Mass Storage
`(e.g., for Software) and
`Storage for Cell Based
`information Source
`K
`355
`
`\ 350
`
`Data Processing Unit
`(e.g., Computer System)
`
`=
`
`\\ 351
`
`V
`
`MODEM or
`Other Interface A 352
`
`To / From Other Processors
`(e.g., Computers on
`Network or Through
`Phone System
`
`364
`
`FIG. 6
`
`Apple, Inc. Exhibit 1038 Page 11
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 10 0f 15
`
`US 6,208,290 B1
`
`ix‘ 377
`
`‘—l
`
`379
`
`375 \_->
`
`GPS
`Receiver
`
`i
`376
`
`‘
`
`:
`
`l
`380
`
`Communication
`System
`Transcelver
`t
`378
`
`Fl G. 7A
`
`GPS
`Antenna
`
`401
`
`<
`
`405
`
`'
`l” 409
`Comm-
`Antenna GPS L.O.'S
`
`(
`Analog to
`
`=
`
`Converter
`
`403 R7
`
`3
`
`416
`(
`Analog to
`Digital ——
`Converter
`
`( 41 a
`Comm. Signals
`RF to IF
`Converter
`l" 415
`I Comm.
`Signals L.O. s
`
`=
`
`_
`
`423
`(
`
`(
`Switch
`
`a‘
`
`:
`:
`
`418 "4
`
`Pro ram
`420 “ Mergtltory
`
`)
`Digital
`Memory
`‘l
`
`M
`
`" " (421
`Processor
`
`426'4
`"
`Modulator
`L
`425
`
`435 v
`
`1409
`415 q‘
`Frequency
`Synthesizer T>
`\ 424 426
`
`I
`Transmit
`Power
`COI'IUOI
`
`431a
`(
`434
`(
`—\ 431
`
`Transmit/
`Receive <
`Switch
`r
`433
`
`IF to RF <
`Converter
`t
`426
`
`\ 427
`
`Apple, Inc. Exhibit 1038 Page 12
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 11 0f 15
`
`US 6,208,290 B1
`
`Determine a Plurality of Approximate
`Doppler Data from an Approximate Location
`(Based on at Least One of a Location
`of a Wireless Cell Site or a Location of
`a Cellular Service Area Which Includes
`the Wireless Cell Site)
`
`Broadcast the Plurality of Approximate
`Doppler Data from a Wireless Cellular
`Transmitter to a Plurality of SPS
`Receivers Serviced by the
`Wireless Cell Site
`
`l
`
`l
`l
`
`Receive a Plurality of Pseudoranges
`from an SPS Receiver
`
`Determine a Position of the SPS Receiver
`Using The Plurality of Pseudoranges and
`the Approximate Location (in Order to
`Allow the Position Calculations to Converge
`Quickly to the Position Solution)
`
`FIG. 8
`
`’\/ 501
`
`’\ 503
`
`v 505
`
`’-\ 507
`
`Apple, Inc. Exhibit 1038 Page 13
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 12 0f 15
`
`US 6,208,290 B1
`
`Determine a Location From a Cell Based
`Information Source (the Location is Based
`on at Least One of a Location of a Cellular \/ 530
`Service Area or a Location of a Wireless
`Cell Site in the Cellular Service Area)
`
`l
`
`Determine a Plurality of Satellite Ephemeris
`Data for a Corresponding Plurality of A 532
`Satellites Which are in View of the Location
`
`l
`
`Transmit the Plurality of Satellite Ephemeris
`Data from the Wireless Cell Site to One or M 534
`More SPS Receivers in the Cellular Service
`Area
`
`FIG. 9
`
`Apple, Inc. Exhibit 1038 Page 14
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 13 0f 15
`
`US 6,208,290 B1
`
`Communication
`Signal
`
`101
`
`K120
`Communication Receiver
`
`Channel Tuning
`
`RF to IF
`' Convert
`J
`102
`
`'
`
`104
`J
`
`PN Acquisition &
`Trackmg
`PN
`VCO
`2.4576
`103)
`113x MHz
`
`105
`
`v
`
`Phaseiock Loop
`
`GPS Signal
`
`121
`
`\a
`
`_
`
`-
`
`(108
`N_3 TN—|+1073
`‘ Loop
`Phase
`I
`]
`Detector ' Filter
`
`M = 5
`
`—:- M
`
`4.096 MHz
`
`\
`106
`
`114 \\
`
`109
`
`110
`
`122
`
`1
`
`111
`
`r
`
`: RF to IF
`Convert
`
`117
`(
`
`-
`‘ GPS Signal ’\
`# Processor
`113a
`
`Al L08
`
`Frequency
`Synthesizer
`)
`112
`
`A
`’\
`Sample Clock 115
`
`4
`‘REF Freq. In
`
`GPS Receiver
`
`FIG. 10A
`
`Apple, Inc. Exhibit 1038 Page 15
`
`

`
`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 14 0f 15
`
`US 6,208,290 B1
`
`Communication
`Signal
`
`201
`
`220
`/
`Communication Receiver
`
`Channel Tuning
`
`TDMA Symbol
`
`\ RF to IF
`Convert
`)
`202
`
`‘
`'
`
`304
`
`Ac_lc_iuisli(tion &
`[ac mg
`Symbol Sync
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`GPS Signal
`
`512 kHz
`
`Freq. Ref.
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`Digital
`Synthesizer
`\
`
`Progr. Freq. =
`023631
`
`222
`
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`
`211
`
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`
`‘ RFto IF
`Convert
`
`(217
`
`; GPS Signal »\
`Processor
`213a
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`
`Frequency
`Synthesizer
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`212
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`21
`5
`Sample Clock
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`REF Freq In
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`GPS Receiver
`
`FIG. 10B
`
`Apple, Inc. Exhibit 1038 Page 16
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`

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`U.S. Patent
`
`Mar. 27, 2001
`
`Sheet 15 0f 15
`
`US 6,208,290 B1
`
`Receive a Communication Signal Having
`a Carrier Frequency and a Data Signal
`Modulated on the Carrier Frequency
`
`\_/ 602
`
`V
`
`Extract a Reference Signal from the
`.
`Data Signal
`
`,_\
`604
`
`Use the Reference Signal to Provide
`a Local Oscillator Signal to Acquire N 606
`SPS Signals
`
`FIG. 11A
`
`Receive a Communication Signal Having
`a Carrier Frequency and a Data Signal \/ 610
`Modulated on the Carrier Frequency
`
`Acquire and Track the Data Signal
`Which is Received in a Communication ’\ 612
`Receiver
`
`Generate a First Local Oscillator
`Signal Which is Corrected by the Tracked \/ 614
`Data Signal
`
`V
`Use the First Local Oscillator Signal
`to Generate a Second Local Oscillator /\
`Signal Which is Used to Acquire
`616
`SPS Signals
`
`FIG. 11B
`
`Apple, Inc. Exhibit 1038 Page 17
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`1
`GPS RECEIVER UTILIZING A
`COMMUNICATION LINK
`RELATED APPLICATIONS
`This application is a continuation-in-part of US. patent
`application Ser. No. 08/759,523, ?led on Dec. 4, 1996, now
`US. Pat. No. 5,841,396 by Norman F. Krasner and a
`continuation-in-part of US. patent application Ser. No.
`08/612,582, ?led on Mar. 8, 1996, now US. Pat. No.
`5,874,914 by Norman F. Krasner.
`This application is also related to and hereby claims the
`bene?t of the ?ling date of a provisional patent application
`by the same inventor, Norman F. Krasner, Which application
`is entitled LoW PoWer, Sensitive Pseudorange Measurement
`Apparatus and Method for Global Positioning Satellites
`Systems, Ser. No. 60/005,318, ?led Oct. 9, 1995.
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to receivers capable of
`determining position information of satellites and, in
`particular, relates to such receivers Which ?nd application in
`satellite positioning systems (SPS) such as the US. global
`positioning satellite (GPS) systems.
`2. Background Art
`GPS receivers normally determine their position by com
`puting relative times of arrival of signals transmitted simul
`taneously from a multiplicity of GPS (or NAVSTAR) sat
`ellites. These satellites transmit, as part of their message,
`both satellite positioning data as Well as data on clock
`timing, so-called “ephemeris” data. The process of searching
`for and acquiring GPS signals, reading the ephemeris data
`for a multiplicity of satellites and computing the location of
`the receiver from this data is time consuming, often requir
`ing several minutes. In many cases, this lengthy processing
`time is unacceptable and, furthermore, greatly limits battery
`life in micro-miniaturiZed portable applications.
`Another limitation of current GPS receivers is that their
`operation is limited to situations in Which multiple satellites
`are clearly in vieW, Without obstructions, and Where a good
`quality antenna is properly positioned to receive such sig
`nals. As such, they normally are unusable in portable, body
`mounted applications; in areas Where there is signi?cant
`foliage or building blockage; and in in-building applications.
`There are tWo principal functions of GPS receiving sys
`tems: (1) computation of the pseudoranges to the various
`GPS satellites, and (2) computation of the position of the
`receiving platform using these pseudoranges and satellite
`timing and ephemeris data. The pseudoranges are simply the
`time delays measured betWeen the received signal from each
`satellite and a local clock. The satellite ephemeris and timing
`data is extracted from the GPS signal once it is acquired and
`tracked. As stated above, collecting this information nor
`mally takes a relatively long time (30 seconds to several
`minutes) and must be accomplished With a good received
`signal level in order to achieve loW error rates.
`Virtually all knoWn GPS receivers utiliZe correlation
`methods to compute pseudoranges. These correlation meth
`ods are performed in real time, often With hardWare corr
`elators. GPS signals contain high rate repetitive signals
`called pseudorandom (PN) sequences. The codes available
`for civilian applications are called C/A codes, and have a
`binary phase-reversal rate, or “chipping” rate, of 1.023 MHZ
`and a repetition period of 1023 chips for a code period of 1
`msec. The code sequences belong to a family knoWn as Gold
`codes. Each GPS satellite broadcasts a signal With a unique
`Gold code.
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`For a signal received from a given GPS satellite, folloW
`ing a doWnconversion process to baseband, a correlation
`receiver multiplies the received signal by a stored replica of
`the appropriate Gold code contained Within its local
`memory, and then integrates, or loWpass ?lters, the product
`in order to obtain an indication of the presence of the signal.
`This process is termed a “correlation” operation. By sequen
`tially adjusting the relative timing of this stored replica
`relative to the received signal, and observing the correlation
`output, the receiver can determine the time delay betWeen
`the received signal and a local clock. The initial determina
`tion of the presence of such an output is termed “acquisi
`tion.” Once acquisition occurs, the process enters the “track
`ing” phase in Which the timing of the local reference is
`adjusted in small amounts in order to maintain a high
`correlation output. The correlation output during the track
`ing phase may be vieWed as the GPS signal With the
`pseudorandom code removed, or, in common terminology,
`“despread.” This signal is narroW band, With bandWidth
`commensurate With a 50 bit per second binary phase shift
`keyed data signal Which is superimposed on the GPS Wave
`form.
`The correlation acquisition process is very time
`consuming, especially if received signals are Weak. To
`improve acquisition time, many GPS receivers utiliZe a
`multiplicity of correlators (up to 12 typically) Which alloWs
`a parallel search for correlation peaks.
`Another approach to improve acquisition time is
`described in US. Pat. No. 4,445,118, referred to as the
`“Taylor patent.” This approach uses the transmission of
`Doppler information from a control basestation to a remote
`GPS receiver unit in order to aid in GPS signal acquisition.
`While this approach does improve acquisition time, the
`Doppler information is transmitted from a basestation to a
`mobile GPS receiver by a point to point transmission
`system, and there is no indication of hoW this Doppler
`information is obtained.
`An approach for improving the accuracy of the position
`determination by a remote GPS receiver unit is also
`described in the Taylor patent. In the Taylor patent, a stable
`frequency reference is transmitted to a remote GPS receiver
`unit from a basestation in order to eliminate a source of error
`due to a poor quality local oscillator at the remote GPS
`receiver unit. This method uses a special frequency shift
`keyed (FSK) signal that must be situated in frequency very
`close to the GPS signal frequency. As shoWn in FIG. 4 of the
`Taylor patent, the special FSK signal is about 20 MHZ beloW
`the 1575 MHZ GPS signal Which is also received by the
`receiver in order to demodulate the GPS satellite signals
`from the GPS satellites so as to eXtract satellite position data.
`Moreover, the approach described in the Taylor patent uses
`a common mode rejection mechanism in Which any error in
`the local oscillator (shoWn as L0. 52) of the receiver Will
`appear in both the GPS channel and the reference channel
`and hence be canceled out. There is no attempt to detect or
`measure this error. This approach is sometimes referred to as
`a homodyne operation. While this approach provides some
`advantages, it requires that the tWo channels be closely
`matched, including closely matched in frequency. Moreover,
`this approach requires that both frequencies remain ?xed, so
`frequency hopping or frequency tuning (channeliZation)
`techniques are not compatible With this approach.
`
`SUMMARY OF THE INVENTION
`
`In one aspect of the present invention, a method is
`described for reducing processing time due to Doppler error
`
`Apple, Inc. Exhibit 1038 Page 18
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`in a satellite positioning system (SPS) receiver having a cell
`based communication receiver. The method includes deter
`mining an approximate location of the SPS receiver from a
`cell based information source. This approximate location is
`determined by using at least one of a location of a cellular
`service area Which includes a cell site Which is capable of
`communicating With the cell based communication receiver
`or a location of the cell site itself. The method further
`includes determining an approximate Doppler for at least
`one SPS satellite relative to the SPS receiver, Where the
`approximate Doppler is based upon the approximate loca
`tion. This approximate Doppler is used in the SPS receiver
`to reduce processing time in either determining at least one
`pseudorange to the at least one SPS satellite, or in acquiring
`signals from the at least one SPS satellite.
`An exemplary embodiment of this method is a cellular
`telephone Which includes a GPS receiver. The cellular
`telephone operates by communicating With cell sites, each of
`Which are connected to a cellular sWitching center. A
`database, Which represents a cellular based information
`source, may be maintained at the cellular sWitching center or
`at the cell site or at a remote processing station, Which may
`be termed a “server,” may be used to determine an approxi
`mate location of the cellular telephone based upon the cell
`site (or cellular service area) With Which the cellular tele
`phone is communicating. This approximate location may
`then be used to derive an approximate Doppler relative to the
`various SPS satellites Which are transmitting SPS signals to
`the GPS receiver in the cellular telephone. This approximate
`Doppler is then transmitted in one embodiment from the cell
`site to the cellular telephone, and is then used in the GPS
`receiver in order to reduce processing time due to Doppler
`induced effects in the GPS receiver.
`Afurther embodiment of this aspect of the present inven
`tion is a data processing station Which includes a processor
`and a storage device coupled to the processor, and a trans
`ceiver coupled to the processor. The transceiver is for
`coupling the data processing station to a Wireless cell site.
`The storage device contains information specifying at least
`one approximate Doppler at a given time for an approximate
`location Which is determined by at least one of a location of
`a cellular service area Which includes the Wireless cell site
`or a location of the Wireless cell site itself. The transceiver
`receives a site information Which determines the approxi
`mate location, and the processor determines an approximate
`Doppler for at least one SPS satellite Which is in vieW of said
`approximate location. The approximate Doppler is based
`upon the approximate location. The transceiver sends this
`approximate Doppler to the Wireless cell site Which then
`transmits the approximate Doppler to a cell based commu
`nication receiver Which is coupled to an SPS receiver.
`Another aspect of the present invention relates to a
`method for providing a local oscillator signal in a mobile
`satellite positioning system receiver. The method includes
`receiving a signal having a carrier frequency and a data
`signal modulated on the carrier frequency, extracting a
`reference signal from the data signal modulated on the
`carrier frequency, and using the reference signal to provide
`a local oscillator signal to acquire SPS signals from SPS
`satellites.
`Another embodiment according to this aspect of the
`present invention, is a combined SPS receiver and commu
`nication system. The communication system includes an
`acquisition and tracking circuitry Which is coupled to an
`antenna to receive the communication signals. This acqui
`sition and tracking circuitry acquires and tracks the data
`signal Which is modulated onto a carrier frequency and
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`provides a reference signal from the data signal modulated
`on the carrier frequency. The reference signal is then pro
`vided to a phaselock loop or to a frequency synthesiZer in
`order to generate a local oscillator signal Which is used to
`acquire SPS signals in the SPS receiver.
`In another aspect of the present invention, a method for
`determining a position of an SPS receiver having a Wireless
`cell based transmitter is described. This method includes
`determining an approximate location of the SPS receiver
`from a cell based information source. The approximate
`location is determined by at least one of a location of a
`cellular service area Which includes a Wireless cell site
`Which is capable of communicating With the cell based
`transmitter or a location of the Wireless cell site. The SPS
`receiver receives a source of SPS signals and determines a
`plurality of pseudorange data and transmits this plurality of
`pseudorange data to the Wireless cell site. Then a position of
`the SPS receiver is computed by using the SPS signals, the
`plurality of pseudoranges and the approximate location. In
`this method, the approximate location is used to facilitate
`convergence of the position calculation.
`In another aspect of the present invention, a method for
`providing Doppler information to an SPS receiver is
`described. In this method, a plurality of approximate Dop
`pler data from an approximate location is determined. This
`approximate location is based upon at least one of a location
`of a Wireless cell site or a location of a cellular service area
`Which includes the Wireless cell site. The plurality of
`approximate Doppler data is for a corresponding plurality of
`satellites. The method further includes broadcasting the
`plurality of approximate Doppler data from a Wireless cell
`transmitter of the Wireless cell site to a plurality of SPS
`receivers in a cell serviced by the Wireless cell site.
`Typically, at least in one embodiment, the cell site Would
`then receive a plurality of pseudoranges and Would forWard
`these pseudoranges to a remote processing station in Which
`the position of the SPS receiver is computed using the SPS
`signals and the pseudoranges.
`In