CN100544219C - Be used for proofreading and correct the system of multipath error in the telecommunication apparatus navigation system - Google Patents

Abstract

A kind of system that is used for proofreading and correct in the telecommunication apparatus navigation system multipath error is disclosed, reduce the effect that arrives time error, comprise: receiver, reception is from being positioned at the data that the distance transmitter that leaves the receiver unknown distance sends, between the data that receive and the data pattern of being stored, carry out correlation analysis to determine the time of advent by the received data of receiver, when the data that receive were relevant with the data pattern of being stored, this receiver produced a coherent pulse; And analyzer, use the generation time of advent position data relevant with receiver location based on the received data of receiver, coherent pulse is modeled as quadratic equation with a plurality of coefficients, this coefficient is determined by the range value of the coherent pulse of locating at the fixed time, this analyzer calculates the width of this coherent pulse according to quadratic equation, and come the calculation correction factor according to the signal standards that records, to produce calibrated position data, this signal standards is the pulse duration of coherent pulse.

Description

Be used for proofreading and correct the system of multipath error in the telecommunication apparatus navigation system

Invention field

The present invention relates generally to telecommunications, relate in particular to and in telecommunication system, detect and compensate the technology that arrives time error.

Background of invention

Usually ask emergency services with the telephone number as " 911 ".If the caller is in the fixed position, such as a shelter, computer system just can be followed the tracks of the telephone number that Inbound Calls is called out with ANI (ANI), and determines to call out the address of being started apace.Like this, determine that asking the position of emergency services is relative simple task.

Yet can not easily determine customer location, mobile communication such as cell phone, PCS Personal Communications System (PCS) equipment or the like by mobile communication request emergency services.Radio triangulation techniques is used for determining the position of mobile unit for a long time.Yet known this radio triangulation techniques is inaccurate in essence.Usually error is on the order of magnitude of several kms.Yet for the payment of emergency services, this error is unacceptable.

FCC (FCC) has specified the variation of the communication technology, bigger accuracy during this variation meeting permission position is determined.Under the situation of mobile communication, FCC has produced a rule, and its requires position system based on foundation structure in the accuracy (and having 300 meters accuracy under the time 95%) that has 150 meters under 67% time.For the system that requires amended mobile phone, FCC stipulates, and this system must determine the position under 67% time in 50 meters (and under 95% time at 150 meters).

The radio fix system uses (TOA) signal time of advent that comes from the different transmitters of known location to come position of mobile unit is carried out triangulation and estimation.Yet, because many transmission paths, the normally distortion or wrong of the signal time of advent.Fig. 1 has illustrated an example of many transmission paths, and it may be that vehicle 10 interior mobile phones stand.In the described example of Fig. 1, mobile unit 10 is transmitter 12 and 14 received signals from being installed in cat head.In the example of Fig. 1, mobile unit 10 is directly from transmitter 12 and 14 received signals, but the also signal near building reflection of receiver/transmitter 14.Like this, mobile unit 10 receives many signals from transmitter 14.In the described example of Fig. 1, mobile unit 10 is not in the sight line (LOS) of transmitter 16.That is, building or other structure have stopped the direct sight line between mobile unit 10 and the transmitter 16.Yet mobile unit 10 still detects the signal from transmitter 16, and these signals are from the reflection of building or other structure, perhaps along the edge diffraction of building or other structure.In addition, transmitter 16 received signals of mobile unit 10 from being installed in top of building also may be from the global positioning system in Earth's orbit (GPS) satellite received signal.Therefore, mobile unit 10 receives a plurality of signals from transmitter 16, and neither one is direct LOS signal.Signal from gps satellite 18 may also comprise the LOS signal and transmit.As the result of this multipath signal, the measurement time of advent that mobile unit carries out suffers error.When having multipath signal, this error may be significant, thereby is difficult to maybe can not reach the FCC indication about position accuracy.Therefore, be appreciated that being starved of the TOA that a kind of system and method improves the shift position system measures.The invention provides this and other advantage, this will become more obvious from following detailed and accompanying drawing.

Summary of the invention

The present invention is included in and is used for proofreading and correct in the system and method for telecommunication apparatus position system multipath error.Among one embodiment, system comprises receiver, be used to receive from being positioned at the data that the distance transmitter that leaves the receiver unknown distance sends, between the data that receive and the data pattern of being stored, carry out correlation analysis, when the data that receive were relevant with the data pattern of being stored, described receiver produced a coherent pulse; And analyzer, use the generation time of advent position data relevant with receiver location based on the received data of receiver, coherent pulse is modeled as the quadratic equation with a plurality of coefficients, and described coefficient is determined by the range value of the coherent pulse of locating at the fixed time Described analyzer calculates the width of described coherent pulse according to quadratic equation,And come the calculation correction factor according to the signal standards that records, to produce calibrated position data, described signal standards is the pulse duration of coherent pulse.

Among one embodiment, when a data that receive was relevant with the data of being stored, receiver produced a coherent pulse.In this embodiment, signal standards is the pulse duration of coherent pulse.Coherent pulse can be modeled as a quadratic equation, and a plurality of coefficients of this equation are determined by the range value of the coherent pulse at scheduled time place.In another embodiment, receiver produces a signal strength indicator.In this embodiment, signal standards is a signal strength indicator.

System may also comprise a position determination entity, the position that it determines receiver according to the calibrated position data and the known location of distance transmitter.Position data may be based on the time of advent of the received data of receiver.The time of advent, data may be calculated as time of delay or distance, and correlation factor may be calculated as correction time or correction distance.

Among one embodiment, receiver is a cellular part that is operated in the 800MHz frequency band, and analyzer is according to the calculating location data time of advent of the data of the transmission of the distance transmitter in the 800MHz frequency band.Perhaps, receiver may be a part that is operated in the PCS Personal Communications System of 1900MHz frequency band, and analyzer is according to the calculating location data time of advent of the data of the transmission of the distance transmitter in the 1900MHz frequency band.

In also having an embodiment, distance transmitter is a global positioning system (GPS) satellite, and receiver receives data-signal from this gps satellite.In this embodiment, analyzer is according to the calculating location data time of advent of the data that send from gps satellite.

System may comprise also that a data structure stores data, be used for selected signal standards and one or more correction factor are interrelated, wherein analyzer provides the measurement to selected data, as to the input of data structure, and search the correction factor that is associated with the measurement of selected standard and stores.System may or comprise that a data structure stores mathematical function, and this function interrelates selected signal standards and one or more correction factor, and wherein analyzer uses selected standard to come the calculation correction factor in mathematical function.

The accompanying drawing summary

Fig. 1 has illustrated the many RX path between transmission sources and mobile unit.

Fig. 2 is a functional block diagram of realizing system of the present invention.

Fig. 3 is the oscillogram of explanation by the correction signal that system produced of Fig. 2.

Fig. 4 is the chart of functional relation between explanation correlation peak width and range error.

Fig. 5 is the chart of functionality relation between explanation power measurement and range error.

Fig. 6 and 7 forms the flow chart of explanation the present invention operation together.

Detailed description of preferred embodiment

The present invention allows the range error that multipath signal is introduced is carried out quantitative measurment, and provides correction factor to be applied to measure the time of advent, thereby allows more accurate location to determine.In the exemplary embodiment, the present invention is that part with conventional code division multiple access (CDMA) mobile unit realizes.The CDMA mobile unit may be called as mobile unit, cell phone, PCS equipment or analog.With discussed in detail, the invention is not restricted to the special shape of mobile communication equipment as below, also be not limited to particular job frequency of mobile device.

The present invention is included in the system 100 described in Fig. 2 functional block diagram.System 100 comprises a CPU (CPU) 102, the operation of its control system.Person of skill in the art will appreciate that CPU 102 attempts to comprise any treatment facility that can move telecommunication system.This comprises microprocessor, embedded controller, application specific integrated circuit (ASIC), digital signal processor (DSP), state machine, dedicated discrete hardware or the like.The invention is not restricted to realizing CPU 102 selected special hardware assemblies.

System preferably also comprises memory 104, and it may comprise read-only memory (ROM) and random-access memory (ram).Memory 104 provides instruction and data to CPU 102.The part of memory 104 may also comprise nonvolatile RAM (NVRAM).

System 100 generally is included in the Wireless Telecom Equipment as the cell phone, system 100 also comprises outer cover 106, outer cover 106 comprises transmission and the reception with data between permission system 100 and remote location of transmitter 108 and receiver 110, wherein remote location such as cell-site controller (not shown), data such as voice communication.Transmitter 108 and receiver 110 may be combined into transceiver 112.Antenna 114 is attached to outer cover 106, and with transceiver 112 electrical couplings.The operation of transmitter 108, receiver 110 and antenna 114 is known in the art, and need not here describe, unless it is particularly related to the present invention.

In the realization of CDMA equipment, system also comprises a signal detector 116, and it is used to detect and quantizes level by the received signal of transceiver 112.Signal detector 116 detects one or more parameters, such as pilot energy, power spectral density and other parameter of gross energy, every pseudo noise (PN) chip, and this is known in this area.Discussed in more detail below, signal detector 116 is carried out correlation analysis to determine the time of advent (TOA), this position such as transmitter 14 (see figure 1)s from a position.

Signal detector 116 is carried out correlation analysis between reference signal and received signal, and produces a related output signal.Signal analyzer 120 is analyzed this coherent signal and is produced the range correction data with correction data table 122.Among one embodiment, correction data newspaper 122 comprises the data that coherent pulse width and range error are interrelated.Yet, also can use other standard to come the correction distance error.

System 100 comprises timer 124 providing system regularly, and system regularly is used for measuring signal from homology not (as, transmitter 12-16) time of delay in arriving.Timer 124 may be the part of a specific installation or CPU102.

Each assembly of system 100 is coupled by bus system 126, and except data/address bus, bus system 126 may comprise power bus, control signal bus and status signal bus in addition.Yet,, among Fig. 2 each bus is illustrated as bus system 126 in order to simplify.Person of skill in the art will appreciate that the described system 100 of Fig. 2 is functional block diagrams, rather than the tabulation of particular components.For example, although signal detector 116 and signal analyzer 120 are illustrated as two independent blocks in the system 100, yet in fact they can be included in the physical assemblies such as digital signal processor (DSP).They also can be used as program code and reside in the memory 104, the code that code such as CPU 102 are moved.Same consideration can be applied to other assembly that the system 100 of Fig. 2 lists, such as timer 124.

Below with reference to the operation of the assembly shown in the system 100 of Fig. 3-7 key diagram 2.Fig. 3 is a series of waveform sequential charts, and they have illustrated the example of the coherent pulse that is produced by signal detector 116.In order to help to understand rightly the present invention, will provide using the CDMA mobile unit to carry out the concise and to the point description of handling the time of advent by example now.The mobile unit (as, the mobile unit 10 in Fig. 1) of realizing the system 100 of Fig. 2 is assigned to a pseudo noise (PN) sign indicating number at first.The PN sign indicating number can be used as local with reference to being stored in the memory 104.When base station (as, transmitter 12) when data are sent to mobile unit 10, base station PN sign indicating number.System 100 search for continuously local with reference to (that is the PN sign indicating number of, being stored) and launch correlation between data (that is the PN sign indicating number that, is sent).

As known in the art, all transmitters (as, transmitter 12-16) all send identical PN sign indicating number, but from the initial accurate known side-play amount that postponed in time of transmission of the PN sign indicating number of each transmitter.Time offset is measured with the multiple of 64 chips.The PN side-play amount is optionally distributed to transmitter, make that the side-play amount in the geographic area spreads as much as possible to avoid the interference between transmitter.Transmitter (as, transmitter 12-16) may be identified by the identification data that is sent, but comes mark with their PN shift time sometimes.For example, transmitter 12 may be identified as PN 300 and indicates it and send the PN sign indicating number in 300 biasing place.In this example, transmitter 14 and 16 can be identified as PN 425 respectively and PN 610 sends the residing offset time of PN sign indicating number separately to indicate.Yet should be appreciated that do not consider how transmitter is labeled, can in signal, set up the relative biasing of other transmitter relatively of each transmitter the information encoded.Receiver 110 (see figure 2)s in the mobile unit 10 can detect from the PN of (as, transmitter 12-16) of each transmitter in this geographic area.

If mobile unit 10 is positioned at transmitter 12, then the transmission time of 100 of transmitter and systems should not postpone.Like this, signal detector 116 (see figure 2)s can detect relevant between the benchmark stored and emission's data immediately.Yet, suppose that mobile unit 10 leaves transmitter 12 some distances, because propagation delay, detect this delay that has when relevant.Signal detector 116 is the benchmark of being stored half-chip relevant up between the benchmark of storing whenever detecting and emission's data that once be shifted.As the skilled personnel can understand, " chip " is the individual data sheet in the PN sequence.Owing to send data with given rate, so chip can be used as THE MEASUREMENT OF TIME.Although this description can characterize with the chronomere of reality, yet more convenient with reference to the chip time, because system 100 carries out its analysis and measurement with the chip time.

Because the propagation velocity of radio signal is known, so delay measurements also can be calculated as distance.Like this, the measurement of time of delay, distance and chip all is tradable.

If the propagation delay between transmitter 12 and the mobile unit 10 is known, so only require two signals to determine the accurate position of mobile unit.For example, may draw a circumference, its radius is corresponding to the propagation delay (is unit with rice) around transmitter 12.Mobile unit 10 must be positioned at the somewhere on this circumference circle.To detect second detected PN sign indicating number from transmitter 14, transmitter 14 sends this PN sign indicating number at PN time slot 425 places.Can allow to measure for second propagation delay time to time of delay from the generation of the coherent pulse of second transmitter (that is, transmitter 14).The radius of the circumference around the transmitter 14 is corresponding to second propagation delay, and this circumference indicates mobile unit 10 must be positioned at somewhere on the girth.According to two known propagation delays, mobile unit 10 must be positioned at the intersection of two circumference.

Yet the propagation delay between transmitter 12 and the mobile unit 10 is unknown.Therefore, system 100 at random distributes any benchmark of zero-lag to first PN sign indicating number that receives.Like this, first received signal directly is not included in the position measurement.From two subsequently the signal of transmitter (as, transmitter 14 and 16) receive and delay arranged with respect to transmitter 12, they be the PN biasing and owing to mobile unit 10 respectively and the result of the propagation delay that produces of transmitter 14 and 16 s' distance.Delay because the PN in the transmission of PN sign indicating number setovers in coherent pulse generates can easily be determined, and make adequate compensation in timing.Yet the difference time of advent between PN sign indicating number transmission and coherent pulse generate is because propagation delay, and therefore owing to the distance between mobile unit 10 and the corresponding transmitter (as, transmitter 14 and 16) produces.The position of mobile unit 10 can be determined according to the accurate TOA from the signal of transmitter 14 and 16.Thereby system 100 requires to receive the PN sign indicating number from three different transmitters.First coherent pulse is used as zero reference, provides suitable delay measurements and use with the relevant excess delay time of remaining two transmitters (as, transmitter 14 and 16).

The relevant output of the sampling that generates by signal detector 116 (see figure 2)s when the waveform of Fig. 3 (A) illustrates without any multipath signal.Signal detector 116 reference data (that is the PN that the is stored) half-chip that once is shifted up to detecting relevant between reference data and the data that receive.The not shown coherent pulse that produces owing to the PN sign indicating number from transmitter 12, this is because it is used as zero reference arbitrarily.The delay that is produced by the PN of transmitter 14 and 16 biasing also is eliminated, and makes the waveform of Fig. 3 that the effect of propagation delay only is shown.In the described example of waveform (A), the about 1.5 chip places of meaning zero reference produce because transmitter 14 caused coherent pulses leaving one's post.Distance dependent between this 1.5 chip delay and transmitter 14 and the mobile unit 10.Like this, can be that the delay that unit (perhaps being unit as required with rice) records is determined the time of advent in order to chip.

The data of sending from transmitter 14 also comprise identification data, make the mobile unit 10 of realization system 100 to be designated source at the detected coherent signal in 1.5 chip places to transmitter 14.Except transmitter 14, the mobile unit 10 of realization system 100 can receive data from transmitter 16.Signal detector 116 can detect local references (that is the PN sign indicating number of, being stored) and relevant between the emission data of transmitter 16.In the described example of waveform (A), the about 4.5 chip places of zero reference detect because from the PN coherent signal that sign indicating number produces of transmitter 16 leaving.This 4.5 chip delay and transmitter 16 to the distance of mobile unit 10 and from transmitter 12 to mobile unit the difference 10 the distance relevant.The signal delay that the signal that transmitter 12 is produced is produced with respect to transmitter 14 400 chips.From producing the moment of the signal that transmitter 12 launched, be moved to this signal till the moment of unit 10 receptions, the delay of 15 chips is arranged.Equally, the moment from transmitter 14 produces signal, be moved to this signal till the moment of unit 10 receptions, the delay of 5 chips is arranged, this is because the propagation delay between transmitter 14 and the mobile unit 10.Therefore, between the reception of the signal that signal that produces at transmitter 12 places and receiver/transmitter 14 places produce, the observed delay in mobile unit 10 places has 410 chips altogether.This 410 chip is from the difference between reception 5 chip delay of the signal of 415 chip delay in the 12 generation signals moment of transmitter and the generation of transmitter 14 places.As mentioned above, the data of sending from transmitter 16 also comprise identification data, make the mobile unit 10 of realization system 100 to be designated source with the detected correlation peak of 4.5 chips to transmitter 12.

In addition, the mobile unit 10 of realization system 100 may detect the pulse from addition of base station transmitter (not shown), perhaps from the pulse of the satellite that uses global positioning system (GPS) signal.As known in the art, in order to determine the position of mobile unit 10, GPS also uses the arrival time data.In an exemplary embodiment, mobile unit 10 determines to arrive time data from three or more different transmitter.As mentioned above, first coherent pulse is used as zero reference, and the relative delay of other coherent pulse is used to determine according to the time of advent of other coherent pulse the position of mobile unit 10.Without any multipath effect the time, the described pulse of waveform (A) provides relatively accurate time of advent to measure, and therefore can be used for determining exactly the position of mobile unit 10.

Under current telecommunication standard, for example (,) IS-801, it is the CDMA standard of location positioning, perhaps mobile unit 10 can be carried out with the TOA data and calculate to determine its position.Yet the position of mobile unit 10 also can be determined with the part of fixed infrastructure.In this embodiment, mobile unit sends to remote location to identification data and delay measurements data, such as transmitter 14.The position judgement entity (PDE) relevant with transmitter 14 carried out and calculated and according to the known location of each transmitter and the position of calculating mobile unit 10 from the delayed data that each transmitter records.Following table 1 has illustrated the sampled data that sends to the PDE relevant with transmitter 14 from mobile unit 10:

The PN biasing	Postpone (is unit with rice)
		300	0
425	1500
		610	450

Table 1

As known in the art, and top concise and to the point discussion, the PN value of each transmitter (as, transmitter 12-16) is meant that each transmitter begins to send the PN biasing of PN sign indicating number.In the described example of table 1, be that unit calculates excess delay (that is, not owing to the delay of PN biasing) and excess delay is converted to rice with the chip be the delay of unit.For the waveform (A) of Fig. 3, produce coherent pulse respectively at 1.5 and 4.5 chip places from two coherent pulses of transmitter (as, transmitter 14 and 16).Data in the table 1 comprise that the PN relevant with each transmitter setovers and based on relative excess delay time of the delay of pulse arrival time.

PDE uses identification code to determine which transmitter and each excess delay time correlation.Because the position of transmitter all is known, therefore according to determining that from the delay of each corresponding transmitter the position of mobile unit 10 is relatively simply to calculate.This computational process is known in the art, and need not describe here again.

Unfortunately, multipath effect is present in nearly all TOA measurement.Although use the satellite-signal of GPS position technique to be tending towards having less multipath effect, yet these effects still exist.Multipath effect from gps satellite (as, gps satellite 18) is general especially in the urban area, and building and other man-made structures are disturbed gps signal in the city.Ground system, such as transmitter 12-16 (see figure 1)s also are subjected to the influence of artificial building, make signal be refracted and/or reflect.Therefore, mobile unit 10 receives a plurality of images of same signal.System 100 can estimate from the error of multipath effect generation.These multipath effects may be called " short multipath effect ", this is because a plurality of signals generally only postpone a small amount of time, and can arrive the antenna 114 (see figure 2) places of system 100, make that the corresponding time of advent is too approaching so that produce different peak values in the total correlation function.That is, signal makes that arriving in the short time period like this output of signal detector 116 is individual distortion pulses, and this pulse is to produce from the eclipsing effects of a plurality of institutes detection signal.

In the example of being discussed about the waveform (A) of Fig. 3, mobile unit 10 receives individual signals from transmitter 14 and transmitter 16, and does not have multipath signal in front.The effect of a plurality of signals illustrates that in the waveform (B) of Fig. 3 wherein signal detector 116 illustrates a correlation, and it has much wide pulse duration, the result who repeatedly receives as same signal in the short time period.Shown in waveform (A), signal detector 116 produces a broad pulse, but not produces narrow relatively pulse with 1.5 chips, thereby is difficult to determine exactly the time of advent, and this is because system is designed to the detection peak signal.In waveform (B), the peak value of signal is between 1.5-2.5 chips.Similarly, in the waveform of Fig. 3 (B) correlation that produces has been described also from the signal that transmitter 16 receives.Equally, multipath effect causes pulse to broaden, and makes peak value be between the 4.5-5.5 chip.

Should be noted that, the waveform of Fig. 3 (A) and (B) described in effect only be illustrative.Multipath effect may cause signal out of phase to arrive in antenna 114 place's (see figure 2)s, makes signal detector 116 produce a plurality of peak values relevant with individual signals.The present invention provides to small part for the error that produces from multipath effect and has compensated.Bucking-out system described here is not limited to waveform shape or described excess delay time of Fig. 3.

It has been determined that the width (W) of the coherent pulse that signal detector 116 is produced and measure between the interior margin of error time of advent and have functional relation.That is, the width of the coherent pulse that produced of signal detector 116 can be functional relation with the margin of error of the time of advent that is produced by multipath effect in the signal.Functional relation between pulse duration W and delay error can characterize with function f (W).Fig. 4 has illustrated the function f (W) based on field experiment, wherein the actual distance that records is compared with the routine technology institute calculated distance time of advent.Should be noted that pulse duration may be a width greater than 2 the result who lacks sampled value relatively greater than the sawtooth of the curve of 2 chips.Yet the chart of Fig. 4 is clearly shown that the relation between pulse duration and delay error.

Signal analyzer 120 (see figure 2)s are calculated the width W of the coherent pulse that is produced by signal detector 116, and utility function f (W) determines that TOA measures the interior margin of error.

Although have many different technologies can measure the width of coherent pulse, described an example here.System 100 is modeled as quadratic equation to coherent pulse, and determines the coefficient of this quadratic equation with three measured values.These three measured values are data points of selecting from coherent pulse, and comprise the data point with peaked data point and this maximum either side.This illustrates in equation (1) below:

v＝[y(-1)，y(0)，y(1)] (1)

Wherein v is the maximum of correlation function (y (k)) and its two consecutive values.Quadratic equation provides as follows:

y(x)＝ax ²+bx+c (2)

It is that coefficient is the conventional quadratic equation of a, b and c, and y is the amplitude of coherent pulse, and x is time (being that unit is measured in this example with the chip).

Can be with linear equation and the value of coming computing system a, b and c, shown in the following equation (3) with the different value substitution equation (2) of x:

$[a,b,c]\′={\left[\begin{array}{ccc}1& -1& 1\\ 0& 0& 1\\ 1& 1& 1\end{array}\right]}^{-1}*v\′---\left(3\right)$

Wherein at data point x=-1, the value of y is measured at 0,1 every bit place, and determines the value of coefficient a, b and c with the matrix of equation (3).Can determine pulse duration W now.For the consistency of measuring, the width of coherent pulse calculates in system 100 at the distance D place of leaving peak value.This represents in equation (4) below:

ax ²+bx+c＝max*D (4)

Wherein max is the maximum of pulse, and D is peaked predetermined percentage.Among one embodiment, carry out pulse width measuring for the value of D=0.01.That is, multiply by peaked some place and determine the coherent pulse width W at y=0.01.Under logarithmic scale, this is corresponding to peak value following 20 decibels (dB) (that is pulse duration at some place ,-20dB).Selective value-20dB produces consistent result.Yet, it will be understood by those skilled in the art that other value also can be used for system 200 satisfactorily.The present invention is not subjected to the restriction of special technique, and the coherent pulse width can be measured with this special technique.

The coherent pulse width W can with under establish an equation (5) represent:

$W=\frac{\sqrt{b^2-4a(c-D)}}{a}---\left(5\right)$

Wherein all are previously defined.

System 100 realizes function f (W) with the form of correction data table 122 (see figure 2)s.Correction data table 122 can be the part of a specific installation or memory 104.Correction data table 122 can be realized with the data structure of any convenient form.Many data structures are known in the art, and can use satisfactorily.The special shape of data structure is not crucial for correction data table 122 gratifying realizations.Generally speaking, the pulse width W is input in the correction data table 122 as data value, and produces delay error as output from correction data table 122.

In other was realized, function f (W) can realize with mathematical function, but not realize with correction data table 122.Math equation can easily be derived, and the value W that inserts pulse duration there is as variable.In this embodiment, math equation is stored in the data structure, such as memory 104.

According to in-site measurement discussed above, have been found that after the correction factor of having used from correction data table 122 error is lower than 100 meters measurement number has increased by 10%.Therefore, when having multipath signal, system 100 can improve the accuracy of location technology really.

As mentioned above, be used for the current C DMA standard of location positioning, IS-801 provides position measurement, and this is measured by mobile unit and carries out, perhaps by carrying out with the relevant PDE of foundation structure (as, transmitter 14).In the latter's realization, current CDMA standard (that is, IS-801) comprises and does not stipulate and will offer the value W of pulse width and the relevant PDE of transmitter 14 (see figure 1)s.Thereby in an exemplary embodiment, system 100 deducts correlation from the TOA delay distance that is calculated, thereby affords redress in beaming back the data of PDE.By using the example of top table 1, wherein determined 3 transmitter PN biasing numbers and range measurement, signal analyzer 120 calculates the correlation factor (that is delay error) of each measurement according to the pulse duration W relevant with each transmitter.For example, the width of first coherent pulse shown in the waveform of Fig. 3 (B) approximately is 1.5 chips.By using the described function f of Fig. 4 (W), this can be corresponding to the error that is about 100 meters.Signal analyzer 120 is from according to deducting 100 meters automatically the calculated distance value the uncorrected time of advent.For example, delay is that 1500 meters PN425 can be corrected to 1400 meters, and this is because corresponding pulse duration W is 1.3 chips.As mentioned above, signal analyzer 120 usefulness pulse duration W adjust each automatically and postpone, and calibrated data are sent to the PDE that is associated with transmitter 14.Like this, PDE receives the data of having made compensation, remedies the effect of multipath transmission.

In another embodiment, mobile unit self may be PDE.In this incident, signal analyzer 120 is automatically adjusted in the above described manner and is postponed, and calculates these distances with known geometrical calculation, thereby determines the distance between system 100 and each transmitter (as, transmitter 12-16).In this embodiment, must provide information and the identification data relevant, thereby allow the PN sign indicating number to be associated with correct transmitter to system 100 with the position of front transmitter.In also having an embodiment, pulse width data can be sent straight to the PDE that for example is associated with transmitter 14, thereby allows this PDE to carry out compensation adjustment before the position of calculating mobile unit.Therefore, system 100 data type that is not subjected to the position of PDE or is provided for PDE limits.For example, can provide pulse width data, perhaps provide the delayed data that has been compensated for the effect of multipath signal to it to the PDE relevant with transmitter 14.

Also having one to select fully among the embodiment, can use other to measure and compensate multipath effect.For example, can prove that signal strength signal intensity also has functional relation with delay error.In this embodiment, signal analyzer 120 receives a pilot strength indicator (E from signal detector 116 _c/ I _o).The pilot strength signal designator is the pilot energy (E of every PN chip _c) divided by by the received total power spectral density (I of receiver 110 _o) tolerance.Fig. 5 is the curve of the relative pilot signal strength of excess delay.Can notice that from the flow chart of Fig. 5 lower pilot strength signal is represented excess delay (that is error) sometimes.Thereby, can form a function and make excess delay relevant with pilot signal strength.These data can be stored with the form of correction data table 122 (see figure 2)s, and are used in the above described manner.Perhaps, mathematical function can be stored in the system 100, and is handled by signal analyzer 120.In also having an embodiment, can use the combination of choice criteria to determine excess delay.For example, can use pulse duration W and pilot frequency intensity (E _c/ I _o) combination determine excess delay.

Illustrate in the flow chart that operates in Fig. 6 and 7 of system 100.Begin 200 places, system 100 is in operation, and can receive data from transmitter (as, transmitter 12-16).In the judgement 202, system 100 determines whether to produce first coherent pulse by signal detector 116.As known in the art, and concise and to the point description in the above, signal detector 116 is parts of conventional CDMA mobile unit, the PN sign indicating number that its search is sent.When detecting the PN sign indicating number, signal detector 116 produces coherent pulse.If do not detect pulse, then adjudicating 202 result is "No", and system turns back to judgement 202 and coherent pulse to be detected such as comes.When detecting a PN sign indicating number and producing first coherent pulse, the result of judgement 202 is a "Yes", and in step 204, the PN number that system log (SYSLOG) is relevant with transmitter and zero being made as time of delay.In judgement 206, the PN sign indicating numbers from other transmitter to be detected such as system 100.If do not produce any other coherent pulse, then adjudicating 206 result is "No", and system's home position 206, waits the PN sign indicating number from other transmitter to be detected.When the PN sign indicating number that detects from other transmitter (as, transmitter 14 and 16), signal detector 116 produces coherent pulses, and to adjudicate 206 result be "Yes".

When producing coherent pulse, system 100 is the time of delay of record PN number and generation coherent pulse in step 210 just at every turn.In the step 212, system 100 deducts because the caused delay of PN time-slot delay.Remaining delay only is attributable to propagation delay.As previously mentioned, system 100 must detect the PN sign indicating number from least three different transmitters.This can be the combination (as, transmitter 12-16) of ground transmitter or may comprise one or more gps satellite (not shown).Therefore, will repeat to adjudicate 206 and step 210 and 212, and make system 100 that three PN numbers and relevant time of delay be arranged.As described in Figure 7, in step 214, the pulse duration W of the coherent pulse that system's 100 signal calculated detectors 116 are produced.In the step 216, system 100 uses f (W) and comes the time in corrective delay.As previously mentioned, system 100 may directly use a mathematics f (W) and comes the computing relay time.Perhaps, system 100 may use correction data table 122 to search the correction factor of time of delay according to pulse duration W.Perhaps, can replace step 214 and 216, for example from the (E of signal detector 116 with the calculating of signal strength signal intensity _c/ I _o), and use (E _c/ I _o) function f come the time in corrective delay.If selected standard and multipath effect caused time of delay of error is relevant, so also can use other tolerance, such as rms signal intensity, perhaps other standard.

No matter select which kind of bearing calibration, in step 216, all will produce calibrated time of delay utility function time of delay that records.In the step 218, system 100 definite positions of having calculated the transmitter of calibrated time of delay for it.In the step 220, PDE calculates the position of mobile unit 10 and finishes this process at 222 places, wherein determines the position of mobile unit.The accuracy that the position judgement increases is because the minimizing of multipath effect negative effect.

As previously mentioned, if give the accurate position of each transmitter of mobile unit, PDE just can realize in mobile unit self.Under current telecommunication standard, this information is not provided for mobile unit, but is provided for each base station.If PDE and base station (as, transmitter 12) are associated, then mobile unit just detected PN number with send to the PDE relevant time of delay with transmitter 12.The time of delay and the correction factor that record may be comprised time of delay, perhaps calibrated time of delay may be only comprised.In also having an embodiment, system 100 may send to the PDE relevant with transmitter for example 12 to the pulse duration that records, with the calculating of correction factor in the permission PDE.The present invention is not limited by the position of calculating and time of delay of being applied to recording by correction factor, not limited by the position of PDE.

Like this, system 100 provides a kind of technology, can eliminate effective multipath error by it, thereby can determine the position of mobile unit 10 more accurately.If customer requirements emergency services, the accuracy of this increase can be crucial when positioning mobile units.

Should be appreciated that even proposed each embodiment of the present invention and advantage in the superincumbent description, yet top disclosure only is illustrative, and can make detailed variation, this is also in broad principle of the present invention.Therefore, the present invention only is subjected to the restriction of claims.

Claims (12)

1. system that is used for proofreading and correct multipath error in the telecommunication apparatus navigation system, described system comprises:

Receiver is used to receive from being positioned at the data that the distance transmitter that leaves the receiver unknown distance sends;

Signal detector, be used between the data that receive and the data pattern of being stored, carrying out correlation analysis determining the time of advent, and when the data that receive are relevant with the data pattern of being stored, produce a coherent pulse by the received data of receiver; And

Signal analyzer, use the generation time of advent position data relevant with receiver location based on the received data of receiver, coherent pulse is modeled as quadratic equation with a plurality of coefficients, described coefficient is determined by the range value of the coherent pulse of locating at the fixed time, described signal analyzer calculates the width of described coherent pulse according to quadratic equation, and come the calculation correction factor according to the signal standards that records, to produce calibrated position data, described signal standards is the pulse duration of coherent pulse.

2. the system as claimed in claim 1 is characterized in that also comprising a location judgement entity, and it is used for determining according to the known location of calibrated position data and distance transmitter the position of receiver.

3. the system as claimed in claim 1 is characterized in that, be calculated as time of delay the described time of advent, and correction factor is that time delay is proofreaied and correct.

4. the system as claimed in claim 1 is characterized in that, described signal analyzer calculates the amplitude peak of coherent pulse, and measures pulse duration being lower than under the predetermined level of amplitude peak.

5. the system as claimed in claim 1 is characterized in that, described signal standards is a signal strength signal intensity.

6. system as claimed in claim 5 is characterized in that, described signal strength signal intensity is the pilot strength indicator that is generated by described signal detector.

7. the system as claimed in claim 1, it is characterized in that, described receiver is a cellular part that is operated in the 800MHz frequency band, and described signal analyzer is according to the calculating location data time of advent of the data of the transmission of the distance transmitter in the 800MHz frequency band.

8. the system as claimed in claim 1, it is characterized in that, described receiver is a part that is operated in the PCS Personal Communications System phone of 1900MHz frequency band, and described signal analyzer is according to the calculating location data time of advent of the data of the transmission of the distance transmitter in the 1900MHz frequency band.

9. the system as claimed in claim 1, it is characterized in that, described distance transmitter is a GPS satellite, and described receiver receives data-signal from GPS satellite, and described signal analyzer is according to the calculating location data time of advent of the data that send from GPS satellite.

10. the system as claimed in claim 1 is characterized in that, described receiver is the part of code division multiple access phone, and described signal analyzer is according to the calculating location data time of advent of the data of the transmission of the distance transmitter in the 800MHz frequency band.

11. the system as claimed in claim 1, it is characterized in that also comprising a data structure, be used to store the data that signal standards is associated with correction factor, wherein signal analyzer provides the measurement of selected standard, as the input of data structure, and search the correction factor stored relevant with the measurement of selected standard.

12. the system as claimed in claim 1 is characterized in that also comprising a data structure, is used to store the mathematical function that signal standards is associated with correction factor, wherein signal analyzer comes the calculation correction factor with selected standard and mathematical function.

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