CN1695069A - Directly acquiring precision code GPS signals - Google Patents
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- CN1695069A CN1695069A CN 03803346 CN03803346A CN1695069A CN 1695069 A CN1695069 A CN 1695069A CN 03803346 CN03803346 CN 03803346 CN 03803346 A CN03803346 A CN 03803346A CN 1695069 A CN1695069 A CN 1695069A
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Abstract
In general, the invention is directed to techniques for directly acquiring P-codes without first acquiring C/A-codes. For example, in one embodiment, a system comprises an assist server to track a P-code signal from a Global Positioning System GPS satellite and generate acquisition assistance information from the signal. The system further comprises a mobile unit to receive the acquisition assistance data from the assist server, and to acquire the P-code signal from the satellite based on the acquisition assistance data. The acquisition assistance data may include time-of-week data indicating an initial time offset into a P-code pseudorandom code sequence for the satellite. The mobile unit may include a reference generator to locally generate a reference pseudorandom code sequence based on the time-of-week data.
Description
Related application
The application's case advocate on February 8th, 2002 application No. the 60/355th, 212, U.S. Provisional Application case, in the right of priority of No. the 60/362nd, 476, the U.S. Provisional Application case of application on March 6th, 2002.
Technical field
The present invention relates to GPS (GPS), particularly catch from the Satellite GPS signal.
Background technology
GPS (GPS) is a kind of satellite navigation system, and being designed to provide Position, Velocity and Time information in almost any position in the world.GPS is developed by U.S. Department of Defense, comprises a constellation that 24 satellites in the running are arranged now.
GPS provides two kinds of other services of level: standard setting service and accurately positioning service.Standard setting service (SPS) is a kind of location and timing services for all GPS users' uses.SPS utilizes and slightly catches pseudo-random code (C/A sign indicating number) and navigation data message.SPS provides relative, the measurable bearing accuracy of level 100 meters (95%), vertical 156 meters (95%), and the time conversion accuracy does not exceed 340 nanoseconds (95%).
Accurately positioning service (PPS) is a kind of high-precision military location, speed and timing services, and it can be for using continuously in the world through authorized user.PPS utilizes accurately sign indicating number (P sign indicating number), and it mainly is designed to use for US military.Can use the military user equipment of P sign indicating number that level at least 22 meters (95%), vertical 27.7 meters measurable bearing accuracy are provided, the time precision that is converted to universal time (UTC) does not exceed 200 nanoseconds (95%).
Gps satellite is with two L-band frequencies (L1=1575.42MHz and L2=1227.6MHz) emission, three pseudo noises (PRN) ranging code, and use.The C/A sign indicating number of satellites transmits is 1023 pseudo-random binary sequences of bi-phase modulated on GPS L1 carrier signal, and bit rate is 1.023MHz, and the multiple cycle of its code weight is 1 millisecond.
The P sign indicating number of satellites transmits is a very pseudo-random binary sequence of long bi-phase modulated, is approximately 10
14The position, bit rate is 10.23MHz, this sequence can not repeat in 267 days.Unique " week " fragment of each gps satellite emission P sign indicating number sequence, and in this sequence that resets in each week.Being called as the third sign indicating number of Y sign indicating number, is the ciphering sequence that a kind of and P sign indicating number are united use, is used to improve security and anti-duplicity.P sign indicating number and Y sign indicating number all can be on L1 frequency and L2 frequencies.
Designed multiple receiver, be used for the signal of satellites transmits is decoded, to determine position, speed or time.Generally speaking, for gps signal being deciphered and calculated the final position, receiver must be caught the gps signal from or multi-satellite in the visual field, measures and follows the tracks of the signal that is received, and recover navigation data from these signals.
Search and catch gps signal, and the process of calculating the receiver position can expend time in.For example, catch the gps signal that carries the C/A sign indicating number, it is relevant with the slip (free-running) of the C/A sign indicating number sequence of storage inside that mobile device is carried out gps signal usually.Perhaps, mobile device can be collected the snapshot of gps signal one period duration, to catch whole sequence, promptly be longer than 1 millisecond, and by making the relevant time offset (pseudorange) of calculating this satellite of buffering signals with storage C/A sign indicating number sequence.
Except the sign indicating number sequence, navigation message of every satellites transmits, comprising the data that are called " ephemeris ", for example its orbit parameter, clock status, system time and status message.After calculating pseudorange for satellite, mobile device extracts almanac data, and calculates the final position according to the pseudorange that calculates for satellite with from the almanac data that satellite receives.
It is a kind of technology that has been used for the business level mobile device that auxiliary positioning is caught, in order to quicken the acquisition procedure of C/A sign indicating number.According to this method, the acquisition procedure of C/A sign indicating number is distributed between mobile device and the network.Location assist server, continues a fixed position running such as a cellular basestation as a benchmark gps receiver.When a mobile device wished to catch a C/A sign indicating number, this mobile device and location-server communicated, and request comprises the supplementary of almanac data.Mobile device utilizes this almanac data to quicken to be used to catch the correlated process of C/A sign indicating number.Particularly, mobile device can be according to the almanac data evaluation time side-play amount that is received from secondary server, needs the relevant number carried out thereby reduce.
Catch P sign indicating number ratio and catch the more calculating of C/A sign indicating number.For various actual purpose, P sign indicating number sequence is non-repetition.In other words, it is infeasible cushioning whole P sign indicating number sequence, and for a given satellite, one week of P sign indicating number sequence resets once.For this reason, other gps receiver of army grade often utilizes the C/A sign indicating number to quicken to catch the P sign indicating number.In other words, mobile device is at first caught the C/A sign indicating number so that extract almanac data from signal.The almanac data that this device utilization extracts from the C/A sign indicating number quickens to catch the correlated process of P sign indicating number.
But, even when utilizing C/A sign indicating number lock-on signal, this process also needs several minutes usually.Under many circumstances, can not accept this long processing time, and further, the long processing time can greatly be limited the battery life of portable use.Described acquisition procedure can become more difficult in weak signal or interference environment.
Summary of the invention
In general, The present invention be directed to the technology that is used for catching directly, effectively from the P coded signal of gps satellite.In other words, can not need at first to catch from the C/A coded signal of satellite and catch the P coded signal.
For example, in a specific embodiment, a system comprises a secondary server, is used for following the tracks of the signal from GPS (GPS) satellite, and this signal produces acquisition of assistance data certainly.This system further comprises a mobile device, and it is in order to receiving the acquisition of assistance data from this secondary server, and catches P coded signal from this satellite according to this acquisition of assistance data.The starting point of initial time side-play amount that described acquisition of assistance data can be included as a P sign indicating number pseudo-random code sequence of satellite indication data during week.Mobile device can comprise a reference signal generator that is used for according to this starting point reference pseudorandom code sequence of data in situ generation during week.This secondary server can be followed the tracks of and produce acquisition of assistance data from C/A coded signal or P coded signal.Mobile device and secondary server can be by a kind of wired or wireless communication link couples.
In another specific embodiment, a kind of method comprises the acquisition of assistance data of reception from a secondary server, and determines the time offset of the P sign indicating number pseudo-random code sequence relevant with satellite-signal according to this acquisition of assistance data.
In another specific embodiment, a kind of equipment comprises an antenna, is used for receiving the signal from GPS (GPS) satellite; And a radio modem, be used to receive acquisition of assistance data from secondary server.This equipment further comprises a reference signal generator, in order to produce a reference pseudorandom code sequence according to this acquisition of assistance data; And a processor, be used for according to this acquisition of assistance data for to determine a time offset with the P sign indicating number pseudo-random code sequence of this signal correction.
In another specific embodiment, a kind of computer-readable media comprises instruction, these instructions make programmable processor receive acquisition of assistance data from secondary server, and make this programmable processor determine the time offset of the P sign indicating number pseudo-random code sequence relevant with satellite-signal according to this acquisition of assistance data.
The details of one or more specific embodiments of the present invention is listed in accompanying drawing and the following explanation.Other characteristics of the present invention, purpose and advantage can be understood by explanation, drawing and claim.
Description of drawings
Fig. 1 is the calcspar of a kind of example system of explanation, and in this system, a mobile device utilizes supplementary directly to catch the P code GPS signals.
Fig. 2 is the calcspar of an example specific embodiment of this mobile device of explanation.
Fig. 3 is the process flow diagram of the example modes of this mobile device operation of explanation.
Fig. 4 is that to further specify according to these technology be the process flow diagram of the demonstration program of a given satellite compute pseudo-ranges.
Fig. 5 illustrates an example alignment of the numerical data of representing the P code GPS signals.
Fig. 6 is a regularly chart, the example associative operation that its explanation utilizes overlapping store method to carry out according to time uncertainty numerical value by this mobile device.
Fig. 7 is the process flow diagram of explanation example acquisition process when the time, uncertain numerical value was relatively large.
Fig. 8 is the process flow diagram that an explanation is used to catch the self-adaptation acquisition procedure of multi-satellite.
Embodiment
Fig. 1 is the calcspar of an illustrated example system 2, and in this system, mobile device 4 utilizes acquisition of assistance data directly to catch P code GPS signals 6 from satellite 8.Particularly, secondary server 10 continuous monitoring are also followed the tracks of gps signal 6 from satellite 8, and prepare and keep acquisition of assistance data according to these signals.For example, secondary server 10 can be followed the tracks of a P code GPS signals or a C/A coded signal, and extracts acquisition of assistance data from this signal.This acquisition of assistance data may comprise (TOW) information when starting point of each satellite in the satellite 8 is all.In addition, this acquisition of assistance data may further include the almanac data that is extracted from these signals 6, such as satellite (S.V.) identification, clock status, system time, the Doppler shift of every satellite, the status message of the satellite 8 in forward view, or the like.
Secondary server 10 passes to mobile device 4 with this acquisition of assistance data, and as description herein, this device utilizes this acquisition of assistance data directly and efficiently to catch the P coded signal, and does not need at first to catch the C/A coded signal.For example, mobile device 4 utilizes TOW information, is the initial time side-play amount in every satellite selection P sign indicating number sequence in the satellite 6.Mobile device 4 in correlated process with this initial time side-play amount as the reference position in this sequence.Like this, mobile device 4 can significantly shorten acquisition procedure usually, and can catch the P coded signal from satellite 6, and does not need at first to catch the C/A sign indicating number from these satellites.
After catching the P coded signal, mobile device 4 calculates its position, speed or other gps data.Perhaps, mobile device 4 can pass to pseudo range data secondary server 10.According to these pseudo range data, add knowledge about current almanac data, secondary server 10 calculates position, speed or other gps data for mobile device 4, and the gps data that is calculated is passed to mobile device 4.
Mobile device 4 can be can receive gps signal and calculate in the various mobile gps receivers of gps data any.Example comprises the handhold GPS receiver, is installed on a gps receiver on the delivery vehicle, and delivery vehicle comprises aircraft, automobile, tank, ship, or the like.
Secondary server 10 and mobile device 4 can use in the wired or wireless agreement of multiple tradition any one to communicate by letter by link 5, and link 5 can be that a Radio Link, a hardware interface (as serial port or parallel port), Ethernet connect, or the like.A kind of common wireless communication protocol is CDMA (CDMA), in this agreement, carries out a plurality of communications simultaneously by a radio frequency (RF) frequency spectrum.Other example comprises global system for mobile communications (GSM), and it utilizes arrowband time division multiple access (TDMA) transmission data; And GPRS (GPRS).In some specific embodiments, mobile device 4 can integrate gps receiver and radio communication device and be used for voice or data communication.
Secondary server 10 can comprise a high-performance gps receiver with fixed position.For example, secondary server 10 can be coupled to a radio communication base station, be used for communicating by letter smoothly with mobile device 4.
Fig. 2 is a calcspar that describes an example mobile device 4 more in detail.Generally speaking, mobile device 4 comprises a gps antenna 20, frequency demultiplier 22, frequency synthesizer 24, analog to digital converter (ADC) 26, storer 28, digital signal processor (DSP) 30 and reference signal generator 31, is used for receiving and catching gps signal 6.In addition, mobile device 4 comprises radio modem 32 and RF antenna 34, is used for communicating with secondary server 10.
The signal 6 that frequency demultiplier 22 receives from satellite 8 by gps antenna 20, and with these signals and a signal mixing that is produced by frequency synthesizer 24 is in order to being the baseband frequency that is used to handle by the L-band frequency inverted with these signals.Frequency demultiplier 22 can at first be that an intermediate frequency is nursed one's health with these conversion of signals, and then will be baseband frequency through the conversion of signals of conditioning.Perhaps, frequency demultiplier 22 can be implemented a kind of zero intermediate frequency (ZIF) structure, is used for the frequency of L-band directly is converted to base band.
ADC26 samples to baseband signal, and to produce the digitized representations of this signal, the snapshot with this numerical data is stored in the storer 28 then.For example, storer 28 can be stored a continuous cover digitalized data, and corresponding to 100 milliseconds to 1 second or longer continuing of this baseband signal, the time uses in acquisition procedure for digital signal processor 30 usually for it.
Digital signal processor (DSP) 30 communicates with secondary server 10 by radio modem 32 and RF antenna 34.Although do not do explanation in Fig. 2, radio modem 32 generally includes a frequency demultiplier and an analog to digital converter, is used to handle the RF signal that is received from RF antenna 34.Although GPS and cellular communication can shared antennas, preferentially select the antenna of separation for use, because cellular communication and gps signal use different RF wave bands usually.
Digital signal processor (DSP) 30 receives the acquisition of assistance data that comprises starting point information during week from secondary server 10 by RF antenna 34, and this information of storage, to use in acquisition procedure.Digital signal processor (DSP) 30 can be with this information stores in storer 28, inside chip internal storage or other suitable computer-readable media.In addition, digital signal processor (DSP) 30 is operated according to the executable instruction of taking from the computer-readable media usually.The example of described medium comprises random-access memory (ram), ROM (read-only memory) (ROM), non-volatile random access memory (NVRAM), Electrically Erasable Read Only Memory (EEPROM), flash memory, or the like.Although be that the reference digital signal processor is described, in mobile device 4, also can use the flush bonding processor or the controller of other form.
Starting point when week (TOW) information that DSP30 will be received from secondary server 10 passes to reference signal generator 31, and it utilizes this TOW information to produce reference signal 33, is used for relevant with the gps signal data of storer 28 storages.Reference signal generator 31 can be realized by digital circuit, perhaps adopts the form of digital signal processor (DSP) 30 performance of program.
Fig. 3 is the process flow diagram that further specifies the operation of mobile device 4.For quickening acquisition procedure, mobile device 4 receives acquisition of assistance data (42) by radio modem 32 and RF antenna 34 from secondary server 10.Acquisition of assistance data comprises the TOW information of every satellite in the satellite 8, and can comprise additional ephemeris data, such as satellite (S.V.) identification, clock status, system time, the Doppler shift of every satellite, the status message of the satellite 8 in forward view, or the like.
For catching the P code GPS signals, mobile device 4 receives gps signal from satellite 8, and the snapshot of these signals is stored in (44) in the storer 28.Then, mobile device 4 utilizes each each P coded signal of TOW information capture of 8 of launching an artificial satellite.Particularly, reference signal generator 31 produces signal 33 on the spot according to the current satellite 8TOW information of catching, to carry benchmark P sign indicating number sequence (46).In other words, signal 33 can carry a subclass of P sign indicating number sequence according to the satellite 8TOW information of catching.For example, reference signal generator 31 can be selected an initial time side-play amount according to this TOW information in P sign indicating number sequence, and produces a subclass of P sign indicating number sequence, and this subclass is from the improvement of initial time side-play amount or around the initial time side-play amount.Secondary server 10 can a kind of time-based form (as hour: divide: second) transmit this TOW information, also this TOW information can be transmitted as a chip offset in the P sign indicating number sequence.
Be used to catch consensus sequence length that the legacy system of C/A sign indicating number uses a frame corresponding to sequence code, be 1023 chips of C/A sign indicating number, legacy system difference therewith is by the entrained P sign indicating number sequence length of reference signal 33 data quantity stored in the snapshot 28 head and shoulders above.In addition, DSP30 can require to adjust with the uncertain numerical value of the initial time relevant with the TOW information that is received from secondary server 10 size of the snapshot of depositing in the storer 28 according to sensitivity.For example, in some cases, it may just be enough to cushion the data of 100ms, is 1 second or longer reference signal 33 but use length, wherein represents the uncertainty of TOW information in 1 second.
Then, the digitized snapshot of digital signal processor (DSP) 30 by making the gps signal of depositing in reference signal 33 and the storer 28 relevant is satellite side-play amount computing time (pseudorange) (47).Such as hereinafter detailed description, digital signal processor (DSP) 30 has utilized fast Fourier conversion (FFT) algorithm, and a large amount of related operations between institute's deposit data come to calculate very apace pseudorange to this algorithm in reference signal 33 that produces on the spot and storer 28 by carrying out.Particularly, fft algorithm allows to reach simultaneously all these positions of parallel search, thereby when required correlated measure is very big, can quicken required operational process, than the fast several magnitude of classic method.
As noted before, storer 28 is caught the digitalized data stream corresponding to one period relative long term.Utilize the fast convolution method this large data block efficiently to be handled the ability that helps to improve in (for example, when making reception relatively poor because the part of buildings, tree or other barrier stops) processing signals 6 under the low reception level.Digital signal processor (DSP) 30 utilizes that this identical buffered data is visible gps satellite 8 compute pseudo-ranges in the storer 28, and gps satellite 8 is eight in 24 satellites of earth orbital operation normally.(stop as the urban district under the condition) that under the fast-changing situation of signal amplitude compare with traditional Continuous Tracking gps receiver, described method can provide improved performance.
In case digital signal processor 30 has been finished its computation of pseudoranges (48) for each of satellite 8 in the visual field, it is the pseudorange that calculated for every satellite 8 of basis and the position (49) of being calculated mobile device 4 by the ephemeris information that secondary server 10 provides to mobile device 4 just.Perhaps, digital signal processor (DSP) 30 can pass to secondary server 10 with these pseudoranges by modulator-demodular unit 32, and this server provides a final position to calculate.
Fig. 4 is that to further specify be the exemplary process flowchart of a given satellite compute pseudo-ranges.In case obtained the snapshot of gps signal and from the supplementary of catching of secondary server 10, digital signal processor (DSP) is with the benchmark PN sign indicating number sequence of being carried by signal 33 of the data of being caught and generation (50) synchronously.Different with C/A sign indicating number capture technique, in order directly to catch the P code GPS signals, may require digital signal processor (DSP) 30 to handle the code phase of certain limit, it has exceeded the length of a data bit.Correspondingly, to catch traditional gps receiver of P sign indicating number more different with at first catching the C/A sign indicating number, and mobile device 4 is directly set up bit synchronization by the P sign indicating number snapshot of being deposited in the storer 28.In other words, because C/A sign indicating number sequence repeats repeatedly in a single data bit, traditional gps receiver need not paid close attention to an edge in order to catch purpose synchronous.But a difficulty in directly catching the P sign indicating number is exactly: for various actual cause, P sign indicating number sequence is non-repetition.Correspondingly, the bit period that is launched gps signal of depositing repeats in whole snapshot for several times in the storer 28, but does not have the duplication code phase place.
Synchronous for the sign indicating number sequence that the digitalized data that will be deposited in the storer 28 and reference signal generator 31 are produced, digital signal processor (DSP) 30 is associated a time uncertainty numerical value with the TOW information that is received from secondary server 10.More particularly, mobile device 4 is associated some time uncertainty with the TOW information that is received from secondary server 10, and digital signal processor (DSP) 30 is expressed as a time interval with this time uncertainty.Because the influence of some factors (as the communication delay between secondary server 10 and the mobile device 4), the TOW that is received from secondary server 10 may be different with the actual TOW of mobile device 4.In addition, for different communication systems, it also can change.For example, cdma system may have the time delay of an intrinsic scope, and other communication system may have different time delays.
In general, digital signal processor (DSP) 30 makes Digital GPS signal and reference signal 33 synchronous according to the TOW information that is received and time uncertainty.Particularly, digital signal processor (DSP) 30 is at first estimated a position for first edge in institute's digitalized data of depositing in the storer 28.Can utilize 50 bps data transmission to calculate this equipotential edge.Correspondingly, count when this week begins, edge, a position appears in every 20ms.Once edge, position appears in the spreading rate of a given 10.23MHz, per 204600 chips.
Digital signal processor (DSP) 30 is according to judgement of being made and time uncertainty, ignore some chips of the digitizing Data Start of depositing in the reservoir 28 and at some chips of the PN sign indicating number sequence beginning that produces by reference signal generator 31, first edge or before begin correlated process.Like this, digital signal processor (DSP) 30 utilize the TOW information that passes over from secondary server 10 and correlation time uncertainty, produce a benchmark P sign indicating number sequence on the spot, and make sequence that is produced and the data bit of in storer 28, being deposited synchronous.Like this, digital signal processor (DSP) 30 has guaranteed during correlated process, for the chip in the whole bit period is kept correct polarity.
Fig. 5 has illustrated the example alignment of institute's deposit data snapshot in the storer 28, supposes that TOW is between from customary current TOW t
e0 to δ second in, and the supposition δ very little relatively (less than a data bit).In other words, δ represents the TOW that receives from secondary server 10 with respect to the time uncertainty by the mobile device 4 actual TOW of P code GPS signals that receives.
As shown in the figure, t
e+ δ representative is at the code phase at snapshot starting point place, t
0Represent first edge in the snapshot.Suppose and produce one at time t
eThe PN sequence that+δ begins, hypothesis as shown in Figure 5, digital signal processor (DSP) 30 is ignored some samples when (as firm definition) at beginning storer 28 and beginning PN sequence, and these samples are corresponding to from t
e+ δ is to t
0Time.A kind of method of equivalence is at time t
0Begin this PN sequence (meet and limit) by the initial bit border of m, and by some being equivalent to time interval t
e+ δ-t
0Sample enroll the raw data buffer sequence and produce a new buffering.These technique guarantee the PN sequence always have a sample within the data bit.
For processing delay t
e+ δ is to t
eThe data of+2 δ, these technology are deleted some samples when beginning snapshot and PN benchmark, and it equals from t
e+ 2 δ are to t
0Time.Equally, digital signal processor (DSP) 30 can be at time t
0Beginning PN benchmark, and in storer 28, enroll and equal t
e+ 2
δ-t
0Some samples.Can handle next delay scope t according to similar procedure
e+ 2 δ to t
e+ 3 δ, and the follow-up scope that is of a size of δ.
Refer again to Fig. 4, catch making data and the benchmark PN sign indicating number sequence that produced synchronously after (50), digital signal processor (DSP) 30 for example, can be carried out doppler correction (52) to carrier wave by multiply by Doppler's carrier wave correction index.Next, digital signal processor (DSP) 30 utilizes the FFT computing to implement matched filtering.In this process, digital signal processor (DSP) 30 for example, can be carried out doppler correction (54) to baseband signal by multiply by Doppler's carrier wave correction index.
Generally speaking, 30 pairs of a plurality of Doppler's hypothesis of this correlated process digital signal processor (DSP) (" frequency bin ") are carried out doppler searching, to determine a peak value.For example, secondary server 10 can provide the 1000 Hz Doppler indications (indication) of a satellite.Based on this Doppler's indication, digital signal processor (DSP) 30 distributes a frequency increment, and as 50HZ, this will set up many frequency bins effectively around carrier frequency.Digital signal processor (DSP) 30 is carried out related operation to these frequency bins, up to detecting a peak value.
For each receiver, digital signal processor (DSP) 30 is divided into L block with the snapshot data in reference signal 33 and the storer 28, wherein the size of maximum block less than data bit period (204600 P sign indicating number chips) add the TOW that receives with respect to the evaluation time uncertainty of the actual TOW of P code GPS signals.Digital signal processor (DSP) 30 is to each onblock executing matched filter operation, to determine to be comprised in the storer 28 relative timing between snapshot data and the reference signal 33 entrained PN sign indicating number sequences.Simultaneously, digital signal processor (DSP) 30 can compensate the Doppler shift influence to the sampling time.Digital signal processor (DSP) 30 can greatly shorten the computing time of these computings by the fast convolution computing of using present described fft algorithm.
For each block, digital signal processor (DSP) 30 calculates the FFT of snapshot data and the FFT of reference signal 33.Digital signal processor (DSP) 30 multiplies each other the complex conjugate of snapshot and reference signal after carrying out doppler correction.When the time side-play amount equals the relative delay of gps signal, suppose the time and take place that this result has a correlation peak corresponding to the delay of two sequences.Digital signal processor (DSP) 30 is the size of correlation delay set computational data, and the size of many integration blocks is sued for peace, and is also referred to as the back and detects and number.
As shown in Figure 6, digital signal processor (DSP) 30 is by being that the block of N asks convolution to carry out FFT to length, wherein N is the length of the snapshot data of depositing in the storer 28, and it is by the time uncertainty setting value relevant with the TOW information that is received from secondary server 10 of digital signal processor (DSP) 30 bases.Digital signal processor (DSP) 30 carries out zero padding with N-M zero block to reference signal, and wherein M represents bit period.Like this, to the length of benchmark block institute zero padding be exactly the function of the time uncertainty relevant with TOW.
In addition, digital signal processor (DSP) 30 is added to previous block with the data that a kind of overlapping store method will exceed each bit boundary, and as shown in Figure 6, wherein M equals the number of non-zero reference P sign indicating number chip, and N equals the FFT size, is generally 2
18=262144 chips, B equals the data bit size---204600 P sign indicating number chips.As described below, common M≤B.
For example, if R (0) is that the PN sign indicating number is corresponding to time t
0Numerical value, D (0) is first data word in the storer 28, when aiming at first edge, digital signal processor (DSP) 30 is carried out following program as previously mentioned:
First block is asked convolution:
Ref Block 0=[R (0,1,2 ..., M-1) Zeros (1, N-M)], M＜N wherein
Data?Block?0＝D(0，1，2，…，N-1)。
For improving sensitivity, individual (overlapping) block of 30 couples of ensuing L of digital signal processor (DSP) are asked convolution, and calculating is big or small, and these sizes and former block are sued for peace:
Ref?Block?1＝[R(B+[0，1，2，…，M-1])Zeros(1，N-M)]
Data?Block?1＝D(B+[0，1，2，…，N-1])
……
L data block continued this computing.
Ref?Block?L-1＝[R(j×B+[0，1，2，…，M-1]) Zeros(1，N-M)]
Data Block L-1=D (j * B+[0,1,2 ..., N-1]), j=2 wherein, 3 ... L-1
Output data is of a size of N, but because the characteristic of overlapping preservation convolution, has only not comprise in preceding the N-M sample (or " delay ") by what circular convolution obtained and obscure item (an alias term).Usually, digital signal processor (DSP) 30 only keeps these.When the relative timing of skew consensus sequence and data sequence, whole process repeated can be determined other delay.
It should be noted that because only handled the M/10.23 among the 20ms * 10
6S is so may lose some processing.This is a M non-zero sample because of reference signal, they and preceding M sample of each data bit corresponding (the total data position is of a size of 204600).With respect to handling the situation of all data bit, the sensitivity that consequently may lose about 10log (M/204600) dB sometime.
Can overcome this loss by several method.If before carrying out the amplitude square computing, carry out twice convolution (rather than to above convolution of each step execution), and, can obtain additional energy so with results added.For the second time convolution can be utilized reference signal and the block after the change.The processing procedure of first group of reference signal and block begins at M the baseline sample and N the data sample in left side determining, as shown in Figure 6, is referred to herein as convolution OA.Convolution OB has eliminated above loss, and utilizes the reference data that begins when the gradual period of bit period 0 finishes, and finishes when the end of bit period 0.
In other words, and 204600 data sample M (add up to B-M, B=204600) will be by additional N+M-B null value sample, to produce N total baseline sample.This block will be utilized the buffered data that begins at time M, and comprise N total sample.Result with convolution 0B is added on the result of 0A then.Utilize the whole data bit period of 204600 samples, this result has provided complete convolution.Draw attention to once more, obscure for fear of the time and twist, only preserve preceding N-M sample of this convolution usually.
A kind of efficient may higher method be to utilize to be of a size of 204600 FFT.In this technology, gradual period (shaded period) M will be identical with bit period B.This method is saved necessity of all data in the bit period being carried out twice convolution.But implementing this off-standard size may be more more complicated than carrying out radix 2FFT.
And another kind of method can be with lower speed data to be sampled, so that M data sample equals a bit period.But, like this since bandwidth narrow down and may cause losing some sensitivity.Perhaps,, can sample to data, and then carry out FFT with the dual-rate of this speed for the size that equals a data bit.But needed computing time of this method and memory capacity may all can increase.
Refer again to Fig. 4, after using matched filter operation, digital signal processor (DSP) 30 is carried out peak value and is detected (56), to determine the time offset (58) of the satellite of being caught.Particularly, digital signal processor (DSP) 30 calculates M the size that is extracted from the FFT technology, then these sizes is added in the buffering of moving.Digital signal processor (DSP) 30 continues these processes, its number of times equal that the back is detected and number.It should be noted that FFT produces N output sample, but because the zero padding of benchmark block, processing gain is actually the function of M.Digital signal processor (DSP) 30 just calculates the average at runtime buffer then, and deducts from self buffering.Next, digital signal processor (DSP) 30 calculates the RMS noise, and a threshold value of just setting in runtime buffer equals k times of this RMS.Digital signal processor (DSP) 30 can be selected this threshold value, may be to avoid occurring noise spike greater than the situation of threshold value, and this situation is commonly referred to as " false-alarm ".
Fig. 7 is when the time uncertainty relevant with the TOW that is received from secondary server 10 is big, i.e. the process flow diagram of example acquisition process when the time uncertainty has surpassed a data bit period M.As mentioned above, reference signal generator 31 utilizes acquisition of assistance data to produce a signal 33 (60) that comprises reference pseudorandom code on the spot, and the digitized snapshot by making reference signal 33 and gps signal relevant come detection peak (62).As mentioned above, for every satellite, digital signal processor (DSP) 30 is gone up a plurality of Doppler " receiver " and is carried out doppler searching, to determine a peak value.For example, secondary server 10 can provide the 1000Hz Doppler indication of a satellite.Based on this Doppler's indication, digital signal processor (DSP) 30 distributes a frequency increment, and as 50HZ, this will set up many frequency bins around carrier frequency effectively.
If on all Doppler's hypothesis, all do not detect peak value (64), digital signal processor (DSP) 30 will be by carrying out an additional searching with benchmark P sign indicating number with respect to N-M chip of stored snapshot data " slip ", wherein N represents resource block size, and M represents bit period (70).Behind this benchmark P sign indicating number that slides, digital signal processor (DSP) 30 repeats this group convolution algorithm, to determine whether a finding peak value (62) in any receiver.If in all Doppler's hypothesis, all do not detect peak value, just continue moving reference P sign indicating number, up to all time uncertainty scopes depleted (66).It should be noted that the slip each time for benchmark P sign indicating number, digital signal processor (DSP) 30 is foregoing synchronous again to next data bit boundary with snapshot like that.Digital signal processor (DSP) 30 continues these processes, up to having searched for all satellites (74), and calculates final position (76).
Fig. 8 is the process flow diagram that an explanation is used to catch the self-adaptation acquisition procedure of multi-satellite.As mentioned above, reference signal generator 31 produces signal 33 (80) on the spot, and reference signal 33 is relevant with the gps signal digitized snapshot comes detection peak (82) by making.
As mentioned above, for every satellite, digital signal processor (DSP) 30 search a plurality of Doppler " receiver " are to determine a peak value.The number of search receiver in order to reduce, digital signal processor (DSP) 30 at first utilize and search for one of these satellites short integral time, for example a satellite that is positioned at overhead by secondary server 10 indications.For this satellite and integral time, as mentioned above, each in 30 pairs of one group of doppler receivers of digital signal processor (DSP) is carried out search.For example, digital signal processor (DSP) 30 can begin search at an intermediate receiver, and outwards carries out, up to (for example having searched for all receivers, receiver frequency offset 0, side-play amount-50Hz, side-play amount+50Hz, side-play amount-100Hz, side-play amount+100Hz, or the like).Each search will produce one group of output in based on the matched filter operation of FFT.If any output has surpassed a detection threshold (84), digital signal processor (DSP) 30 will show a Preliminary detection, and store this testing result, as current Doppler shift, time offset, or the like (88).After determining a detection, the measurement of the adjacent Doppler shift of digital signal processor (DSP) 30 checks, determining whether to find the detection to these side-play amounts, and whether current Doppler's signal intensity with this judges this detection whether effectively (90) with respect to adjacent Doppler's maximum.If found such maximal value, and the measurement of output signal-to-noise ratio (SNR) is enough high, so that produce pseudorange measurement well, for example, SNR is higher than a threshold value, and digital signal processor (DSP) 30 end are to the processing of this given satellite so.
If do not find detection (not having 90 branch), digital signal processor (DSP) 30 is that this given satellite uses long integral time so, and repeats this process, up to detecting a peak value, perhaps up to reaching maximum integral time (92).
In case catch a satellite, digital signal processor (DSP) 30 utilizes the actual doppler information of this satellite to dwindle the search volume of subsequent satellites.Particularly, after catching a satellite, digital signal processor (DSP) 30 with the Doppler shift of catching satellite as an initial frequency drift amount.This is to have utilized the following fact: specific error source (as the local oscillator drift) may be identical for the multi-satellite Signal Processing.So, utilize the mode that is similar to first satellite-signal of search to search for the signal of second satellite, have suitable output signal-to-noise ratio (SNR) if reach the detection of being made, so just finish processing to this satellite.If multi-satellite is made detection, can use average of their Doppler shifts or weighted value (being weights) to come the doppler searching of initialization so to other satellite with signal to noise ratio (snr).Digital signal processor (DSP) 30 continues these processes, up to searching all satellites (94), and calculates final position (96).
Illustrate, if the initial ranging time is 50ms, for the determined Doppler shift of this satellite is 0, digital signal processor (DSP) may only need by three Doppler's hypothesis of search (receiver) so, and promptly current receiver and two adjacent reception devices just can be realized this result.With the search contrast that this result and utilize 1 second integral time and 9 Doppler to carry out, so the shortening result of search time equals 1s/50ms * 9bins/3bins, it has equaled to reduce 60: 1 calculating number.In addition, even for more weak satellite-signal, correct initialization Doppler shift also can be saved the processing time substantially.
As a kind of variation, digital signal processor (DSP) 30 can be before increasing integral time to all Doppler and one given integral time of all satellite acquisitions.When not which satellite-signal to be not priori (priori) knowledge of preferable signal of the aerial higher satellite in sky (for example corresponding to) about,, this point may be highly beneficial.Perhaps,, can increase integral time to this given satellite and Doppler so, exceed a threshold value, the pseudorange precision that this expression is enough up to signal to noise ratio (snr) in case detection has been made in the given combination of satellite, Doppler and integral time.So digital signal processor (DSP) 30 can be similarly by changing the adjacent Doppler who analyzes this satellite integral time.Because can be not needing extra storage and can not losing first pre-treatment and cross under the data conditions and increase integral time, so this method may have superiority.
Various specific embodiment of the present invention has been described.These and other specific embodiment is included in the scope of claim.
Claims (70)
1. method, it comprises:
Receive acquisition of assistance data from a secondary server; And
According to described acquisition of assistance data for determining a time offset with P sign indicating number pseudo-random code sequence from the signal correction of a satellite.
2. method according to claim 1 further comprises a position determining mobile device according to described time offset.
3. method according to claim 1, wherein said acquisition of assistance data comprise data when the starting point of an initial time side-play amount of indicating described P sign indicating number sequence is all.
4. method according to claim 3, the determining of one of them time offset comprise according to the starting point that is received from described secondary server during week information produce a reference pseudorandom code sequence on the spot.
5. method according to claim 4, the generation of one of them reference pseudorandom code sequence comprise and produce described reference pseudorandom code sequence, in order to comprise the continuous pseudo-random code that begins in described initial time side-play amount in the described P sign indicating number sequence.
6. method according to claim 4 further comprises:
The described signal of digitizing is to produce a digital data stream;
Cushion a certain amount of numerical data; And
Make described buffer digital data relevant with the described reference number sequence that produces on the spot.
7. method according to claim 6 further comprises according to an amount of digital data with the starting point time uncertainty setting value that information the is relevant during week buffering that is received from described secondary server.
8. method according to claim 7, wherein said uncertain numerical value comprise a predetermined uncertain numerical value.
9. method according to claim 6 wherein makes described buffer digital data comprise that with the described relevant step of reference number sequence that produces on the spot to make described numerical data and described reference pseudorandom code sequence synchronous.
10. method according to claim 9 wherein makes described numerical data and described reference pseudorandom code sequence comprise synchronously:
First edge in the estimation storer in institute's poke digital data; And
According to first edge being estimated with the starting point that is received from described secondary server relevant time uncertainty numerical value of information during week, ignore some chips and the interior some chips of described reference pseudorandom code sequence in the described numerical data.
11. method according to claim 6, the described buffer digital data step relevant with the described reference number sequence that produces on the spot comprised: described reference number sequence and numerical data are divided into the block that is of a size of N, and wherein the size N of block is less than adding with the starting point that is received a relevant time uncertainty numerical value of information when all with the data bit period M of described signal correction.
12. method according to claim 6 wherein is divided into described reference number sequence and described numerical data polylith and comprises from described reference number sequence and form the block with M chip and N-M zero padding.
13. method according to claim 6, wherein make the described buffer digital data and relevant the comprising of the described reference number sequence that produces on the spot that each block in the described block is all used matched filter operation one time, to produce a correlation peak that has with respect to a time offset of described reference number sequence.
14. method according to claim 13 further comprises:
When described correlation peak was lower than a peak threshold, with described reference number N-M chip of numerical data slip with respect to described signal, wherein N represented resource block size, and M represents bit period; And
Repeat described matched filter operation.
15. method according to claim 13, wherein described reference number is comprised with respect to described numerical data slip and repeat to slide described reference number, and carry out described correlated process, up to exceed the relevant time uncertainty numerical value of information when all for chip total number that described reference number moved with the starting point that is received from described secondary server.
16. method according to claim 1 further comprises:
A plurality of Doppler are supposed to carry out doppler searching one time, so that determine a Doppler shift for described signal; And
With described Doppler shift as an initial frequency drift amount of catching from the signal of subsequent satellites.
17. method according to claim 16 further comprises:
Utilize a first integral time, to each the execution doppler searching in one group of doppler receiver (doppler bins), to produce one group of output; And
When not detecting effective peak, increase described integral time and repeat described process according to this group output.
18. method according to claim 17 further comprises:
When in the described output any one exceeds a detection threshold, show a Preliminary detection;
Store a current Doppler shift relevant with described Preliminary detection; And
Described Preliminary detection is verified in the output of the adjacent doppler receiver by detecting current doppler receiver.
19. whether method according to claim 18 verifies that wherein described Preliminary detection comprises the output of checking described adjacent Doppler shift, be maximum with the signal intensity of determining current Doppler shift with respect to adjacent Doppler shift.
20. method according to claim 1, wherein said acquisition of assistance data comprise from a mobile device to the visual field in the positional information of starting point doppler information, frequency synchronization information and this satellite of data, described satellite during week of identification, described satellite of satellite.
21. method according to claim 1 further comprises:
With described time offset transmission to described secondary server; And
From described secondary server receiving position data.
22. method according to claim 1 further comprises according to described time offset and calculates a position.
23. a method comprises:
Receive acquisition of assistance data from a secondary server, wherein said acquisition of assistance data is discerned one group of satellite, and comprises data when starting point is all, and data indicated the initial time side-play amount of the P sign indicating number pseudo-random code sequence of every satellite in the described satellite when starting point was all;
Reception is from the signal of described satellite;
The described signal of digitizing is to produce a digital data stream;
The numerical data of buffering some;
Indivedual initial time side-play amounts according to described satellite are that described satellite produces benchmark P sign indicating number pseudo-random code sequence on the spot;
Make the relevant of described numerical data and described reference number sequence, to determine to have the correlation peak of separate time offset amount; And
According to described time offset is that a mobile device is determined a position.
24. method according to claim 23 wherein makes described numerical data comprise with described the relevant of reference number sequence that produces on the spot:
First edge in the numerical data of estimation store memory storage; And
According to first edge being estimated with the starting point that is received from described secondary server relevant time uncertainty numerical value of information during week, ignore the interior some chips of each sequence in some chips in the described numerical data and the described reference pseudorandom code sequence.
25. method according to claim 22, the described buffer digital data step relevant with the described reference number sequence that produces on the spot comprised: described reference number sequence and numerical data are divided into the block that is of a size of N, wherein the size N of block is less than adding and the starting point that received a relevant time uncertainty numerical value of information during week with the data bit period M of described signal correction, and the block of wherein said reference number sequence has M chip and N-M zero padding.
26. method according to claim 23, the described buffer digital data step relevant with the described reference number sequence that produces on the spot comprised in the described block each is all carried out matched filter operation one time, to produce a correlation peak that has with respect to a time offset of described reference number sequence.
27. method according to claim 26 further comprises:
When the correlation peak of a given satellite was lower than a peak threshold, with the reference number of given satellite N-M chip of numerical data slip with respect to described signal, wherein N represented resource block size, and M represents bit period; And
Described given satellite is repeated described matched filter operation.
28. method according to claim 27, wherein comprise and repeat to slide described reference number with respect to the described numerical data described reference number that slides, and carry out described matched filter operation, up to the chip total number that described reference number moved is exceeded one with the starting point that is received from described secondary server relevant time uncertainty numerical value of information during week.
29. method according to claim 23 further comprises:
Utilize the first integral time, in one group of Doppler hypothesis each is carried out doppler searching, so that produce one group of output in the described signal first; And
When in the described output any one surpasses a detection threshold, show a Preliminary detection;
Store a current Doppler shift relevant with described Preliminary detection;
Whether verify described Preliminary detection by the output that detects described adjacent Doppler shift, be maximum with the signal intensity of determining current Doppler shift with respect to adjacent Doppler shift; And
With described Doppler shift as an initial frequency drift amount of catching from the signal of subsequent satellites.
30. method according to claim 1 further comprises:
Described time offset is passed to described server; And
From described server receiving position data.
31. method according to claim 23 further comprises:
A plurality of Doppler are supposed to carry out doppler searching one time, for first signal in the described signal is determined a Doppler shift amount; And
As an initial frequency drift amount, at least one that is used for described other satellite carried out a doppler searching with described Doppler shift amount.
32. a method comprises:
Receive acquisition of assistance data from server; And
Directly catch P coded signal according to described acquisition of assistance data, and need not at first catch C coded signal from described satellite from a satellite.
33. method according to claim 32, wherein said acquisition of assistance data comprise data when the starting point of an initial time side-play amount of indicating described P coded signal is all.
34. method according to claim 33, further comprise according to the starting point that receives from described secondary server during week data in situ produce a reference pseudorandom code sequence.
35. method according to claim 34, wherein directly catch described P coded signal comprise according to described starting point during week data make reference number sequence relevant of described P coded signal and described generation on the spot.
36. a system comprises:
A secondary server is used for following the tracks of a signal from a GPS (GPS) satellite, and catches supplementary by described signal generation; And
A mobile device in order to receiving the acquisition of assistance data from described secondary server, and is caught a P coded signal from described satellite according to described acquisition of assistance data.
37. system according to claim 36, wherein said acquisition of assistance data comprise data when the described satellite starting point of an initial time side-play amount in P sign indicating number pseudo-random code sequence of indication is all.
38. according to the described system of claim 37, wherein said mobile device comprises a reference signal generator, be used for according to described starting point during week data in situ produce a reference pseudorandom code sequence.
39. according to the described system of claim 38, wherein said mobile device makes the relevant of described signal and described reference pseudorandom code sequence according to the described auxiliary signal of catching, to determine the real time side-play amount of described signal with respect to described sign indicating number sequence.
40. according to the described system of claim 39, a relevant time uncertainty numerical value of information when the storage of wherein said mobile device is all with described starting point, and make the relevant of described signal and described reference pseudorandom code according to described time uncertainty numerical value.
41. system according to claim 36, wherein said secondary server is coupled to the base station of a cellular communication system.
42. system according to claim 36, wherein said secondary server is followed the trail of a C/A coded signal, and produces described supplementary from described C/A coded signal.
43. system according to claim 36, wherein said secondary server is followed the trail of a P coded signal, and produces described supplementary from described P coded signal.
44. an equipment comprises:
An antenna is used to receive a signal from a satellite;
A radio modem is used to receive the acquisition of assistance data from a secondary server;
A reference signal generator is used for producing a reference pseudorandom code sequence according to described acquisition of assistance data; And
A processor is used for according to described acquisition of assistance data for to determine a time offset with a P sign indicating number pseudo-random code sequence of described signal correction.
45. according to the described equipment of claim 44, wherein said processor is determined the position of a mobile device according to described time offset.
46. according to the described equipment of claim 44, wherein said acquisition of assistance data comprises data when the starting point of an initial time side-play amount of indicating P sign indicating number sequence is all.
47., further comprise according to the described equipment of claim 44:
An analog to digital converter is used for producing a digital data stream from described gps signal; And
Medium are used to cushion the described numerical data of some.
48. according to the described equipment of claim 47, wherein said processor is according to an amount with the starting point time uncertainty setting value buffer digital data that information is relevant during week that are received from described secondary server.
49. according to the described equipment of claim 47, wherein said processor makes described buffer digital data relevant with the described reference number sequence that produces on the spot, with thinking that described signal determines a correlation peak.
50. according to the described equipment of claim 47, wherein said processor makes described numerical data and described reference pseudorandom code sequence synchronous.
51. according to the described equipment of claim 50, wherein said processor is by making described numerical data and described reference pseudorandom code synchronous to the estimation that is stored in first edge in the numerical data in the storer, and according to first edge being estimated and with a time uncertainty numerical value of starting point signal correction during week that is received from described secondary server, ignore some chips in the described numerical data and the some chips in the described reference pseudorandom code sequence.
52. according to the described equipment of claim 47, wherein said processor is divided into the block that is of a size of N with described reference number sequence and described numerical data, wherein said resource block size N is less than adding and an institute reception starting point relevant time uncertainty numerical value of information during week with a data bit period M of described signal correction, and make the relevant of described buffer digital data and the described reference number sequence that produces on the spot, with definite correlation peak.
53. according to the described equipment of claim 52, wherein said processor forms the block with M chip and N-M zero padding from described reference number sequence.
54. according to the described equipment of claim 52, when wherein said processor is lower than a peak threshold at described correlation peak, with described reference number N-M chip of numerical data slip with respect to described signal, wherein N represents described resource block size, and M represents described bit period; And repeat described matched filter operation.
55. according to the described equipment of claim 54, wherein said processor repeat to slide described reference number and carry out described correlated process exceeds a relevant time uncertainty numerical value of information when all with the starting point that is received from described secondary server up to the chip sum that moves of described reference number.
56. according to the described equipment of claim 44, wherein said processor supposes to carry out doppler searching to some Doppler, with thinking that described signal determines a Doppler shift, and with described Doppler shift as the initial frequency drift amount of catching from the signal of subsequent satellites.
57. according to the described equipment of claim 56, wherein said processor utilizes a first integral time to each the execution doppler searching in one group of doppler receiver, to produce one group of output, and when not detecting effective peak, increase integral time and repeat described process according to this group output.
58. according to the described equipment of claim 57, wherein said processor any one in described output shows a Preliminary detection during greater than a detection threshold, store the current Doppler shift relevant, and verify the validity of described Preliminary detection by the output of checking adjacent Doppler frequency with described Preliminary detection.
59. according to the described equipment of claim 44, wherein said acquisition of assistance data comprises data, the doppler information of described satellite, frequency synchronization information when the starting point of the identification of satellite in the mobile device visual field, described satellite is all, and the positional information of described satellite.
60. according to the described equipment of claim 44, wherein said processor comprises a digital signal processor (DSP).
61. a computer-readable media comprises instruction, is used to make a programmable processor:
Receive acquisition of assistance data from a secondary server; And
According to described acquisition of assistance data for determining a time offset with P sign indicating number pseudo-random code sequence from the signal correction of a satellite.
62. according to the described computer-readable media of claim 61, wherein said instruction makes described processor determine the position of a mobile device according to described time offset.
63. according to the described computer-readable media of claim 61, wherein said acquisition of assistance data comprises data when the starting point of an initial time side-play amount of indicating P sign indicating number sequence is all.
64. according to the described computer-readable media of claim 63, data in situ produced a reference pseudorandom code sequence when starting point that wherein said instruction makes described processor basis be received from described secondary server was all.
65. according to the described computer-readable media of claim 63, a relevant time uncertainty numerical value of information was set the buffer digital data volume that is used for representing described signal when wherein said instruction made described processor basis all with the starting point that is received from described secondary server.
66. according to the described computer-readable media of claim 64, wherein said instruction makes described processor:
First edge in the estimation storer in institute's poke digital data; And
According to first edge being estimated with the starting point that is received from described secondary server relevant time uncertainty numerical value of information during week, ignore some chips and the interior some chips of described reference pseudorandom code sequence in the described numerical data.
67. according to the described computer-readable media of claim 64, wherein said instruction makes described processor that described reference number sequence and described numerical data are divided into the block that is of a size of N, wherein said resource block size N is less than adding and an institute reception starting point relevant time uncertainty numerical value of information during week with a data bit period M of described signal correction, and make described buffer digital data relevant with the described reference number sequence that produces on the spot, to determine a correlation peak.
68. according to the described computer-readable media of claim 67, wherein said instruction makes described processor form the block with M chip and N-M zero padding from described reference number sequence.
69. according to the described computer-readable media of claim 67, described instruction makes described processor when described correlation peak is lower than a peak threshold, with described reference number N-M chip of numerical data slip with respect to described signal, wherein N represents described resource block size, and M represents described bit period; And repeat described matched filter operation.
70. according to the described computer-readable media of claim 69, described instruction makes described processor repeat to slide described reference number and carry out described correlated process, exceeds and is received from described secondary server starting point relevant time uncertainty numerical value of information during week up to the slip chip sum of described reference number.
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| US35521202P | 2002-02-08 | 2002-02-08 | |
| US60/355,212 | 2002-02-08 | ||
| US60/362,476 | 2002-03-06 | ||
| US10/283,677 | 2002-10-29 |
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| CN1695069A true CN1695069A (en) | 2005-11-09 |
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| CN 03803346 Pending CN1695069A (en) | 2002-02-08 | 2003-02-07 | Directly acquiring precision code GPS signals |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101464508B (en) * | 2008-12-19 | 2011-05-04 | 苏州莱迪斯特电子有限公司 | Method for capturing C/A code signal of GPS |
| CN102508271A (en) * | 2011-09-29 | 2012-06-20 | 哈尔滨工业大学 | Navigation satellite signal capturing method based on peak value location comparison |
| CN102928859A (en) * | 2008-02-29 | 2013-02-13 | 高通股份有限公司 | Satellite time determination for sps receiver |
| CN107728170A (en) * | 2012-07-31 | 2018-02-23 | 高通股份有限公司 | Device, the method and apparatus of auxiliary are obtained for mobile device |
-
2003
- 2003-02-07 CN CN 03803346 patent/CN1695069A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102928859A (en) * | 2008-02-29 | 2013-02-13 | 高通股份有限公司 | Satellite time determination for sps receiver |
| CN102928859B (en) * | 2008-02-29 | 2015-07-15 | 高通股份有限公司 | Satellite time determination for sps receiver |
| CN101960323B (en) * | 2008-02-29 | 2016-11-09 | 高通股份有限公司 | Satellite time for SPS receiver determines |
| CN101464508B (en) * | 2008-12-19 | 2011-05-04 | 苏州莱迪斯特电子有限公司 | Method for capturing C/A code signal of GPS |
| CN102508271A (en) * | 2011-09-29 | 2012-06-20 | 哈尔滨工业大学 | Navigation satellite signal capturing method based on peak value location comparison |
| CN102508271B (en) * | 2011-09-29 | 2013-06-05 | 哈尔滨工业大学 | Navigation satellite signal capturing method based on peak value location comparison |
| CN107728170A (en) * | 2012-07-31 | 2018-02-23 | 高通股份有限公司 | Device, the method and apparatus of auxiliary are obtained for mobile device |
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