CN100428821C - Method of inhibiting arrival time adding delay error - Google Patents

Abstract

The present invention discloses a method for inhibiting arrival time additional time delay errors, which comprises the following steps: a), parameters needed for obtaining positioning signal power time delay distribution are determined, positioning signals are sought according to the determined parameters, and the power time delay distribution of the positioning signals are obtained; b), the path detection thresholds of each power time delay distribution are determined, path judgment is carried out respectively to corresponding power time delay distribution according to the determined threshold value for obtaining the positions of paths; c), the classes of current communication channels are determined according to the magnitude of current sample variation coefficients, if the current communication channels belong to first class communication channels, step d is carried out, otherwise, the step e is carried out; d), the average value of arrival time TOA additional time delay errors under visual communication channels LOS is estimated, and step f is carried out; e), the average value of TOA additional time delay errors under non-visual communication channels NLOS is estimated; f), the TOA additional time delay errors obtained in step d or step e are inhibited. The method not only can be suitable for various communication channels, but also can enhance the estimation precision of TOA additional time delay errors.

Description

A kind of method that suppresses the additional time delay error time of advent

Technical field

The present invention relates to error inhibition technology, be meant a kind of especially method that the time of advent, (TOA) additional time delay error suppressed.

Background technology

In cellular mobile station navigation system or global positioning system (GPS), because blocking or the fluctuating of landform of surface structures, cause framing signal will be subjected to the influence of multipath inevitably, therefore, from the angle of transmission path signal channel is divided into visual channel (path), will definitely looks three kinds of channel and non-visible channels.When travelling carriage and framing signal dispensing device are in los state, the son that comprises in the first footpath directly causes moving after the promptly first center of energy directly of the barycenter in first footpath, the peak of the correlator output followed the tracks of of location receiver just lags behind with respect to perfect condition, in other words is exactly: added the time delay error that multipath is introduced on desirable TOA time delay; When travelling carriage and framing signal dispensing device were in accurate los state, the son footpath that comprises in the head footpath in the TOA measuring amount caused moving the component behind the barycenter in first footpath, also has the diffraction of signal or the additional time delay component that introduce in the diffraction path; When travelling carriage and framing signal dispensing device are in the NLOS state, the barycenter drift component that the son footpath decline that comprises in the head footpath in the TOA measuring amount causes, also have the additional time delay component of the reflection path introducing of signal, the present invention is referred to as TOA additional time delay error with the TOA measure error of being introduced by described factor under above-mentioned three kinds of channels.TOA additional time delay error can cause position estimation accuracy to reduce, particularly under accurate LOS channel and NLOS channel, TOA additional time delay error will cause cellular mobile station navigation system or GPS navigation system can't or to be difficult to reach the positioning accuracy request of Federal Communications Commission (FCC) regulation, therefore, TOA additional time delay error inhibition technology is the key that guarantees cellular mobile station navigation system or GPS Positioning System, thereby average and the variance of obtaining TOA additional time delay error in real time are basic links realizing that TOA additional time delay error suppresses.

In GPS or agps system (A-GPS), in order to improve the positioning accuracy of GPS receiver under multi-path environment and NLOS environment, U.S. Pat 6313786B1 has provided a kind of method of environmental data collecting, this method is discerned GPS or A-GPS receiver environment of living in, and the size of NLOS error is estimated.The specific implementation process of this method is:

The first step, the environment that may be in GPS or A-GPS receiver segments: be divided into indoor, outdoor two big classes, outdoor environment is divided into subclasses such as suburb, urban district, unscreened open area again, and the urban district further is subdivided into some groups according to the height and the dense degree of building again.Second step, determine the environmental data of the characteristic parameter of one group of satellite-signal as GPS or A-GPS, be used for the environmental form of GPS or A-GPS receiver present position is discerned.Described characteristic parameter mainly comprises: the reception elevation angle of the width of the relevant peaks of the signal to noise ratio of the satellite-signal that receives, the first footpath time delay that receives, correlator output, the Doppler frequency shift of signal, satellite-signal, azimuth etc., such as: all be higher than certain particular value if the signal to noise ratio of several satellite-signals that receive is compared with empirical data, just think that GPS or A-GPS receiver are in unscreened open area; All be lower than certain particular value if the signal to noise ratio of several satellite-signals that receive is compared with empirical data, just think that GPS or A-GPS receiver are in indoor.

The method of estimating the NLOS error size among the patent US 6313786B1 is: at first determine GPS or the residing geographical environment kind of A-GPS according to priori data, and then according to the empirical data of NLOS error under the different geographical environments and current signal characteristic, as elevation angle of the variance of correlator peaks, the satellite-signal that receives etc., estimate the size of NLOS error.The method that patent US 6313786B1 utilizes ambient signal to improve GPS or A-GPS positioning accuracy is: the 1) environmental data that reports according to the GPS or the A-GPS receiver of request location, in conjunction with the data in the experience database, judge GPS or the residing geographical environment type of A-GPS receiver and satellite-signal is selected; 2) in the process that the satellite-signal that receives is selected, reject the relatively poor satellite-signal of those signal qualitys, such as those lower satellite-signals of the signal elevation angle, in remaining satellite-signal, again according to the characteristic parameter value of satellite-signal, as the width of relevant peaks, the variance of relevant peaks width etc., estimate the size of correction; 3) determine the weighted value of different satellite-signals according to the signal environment parameter,, in carrying out location estimation, determine suitable weighted value matrix according to the difference of weighted value.

But, there is following defective in the environmental data collecting method that patent US 6313786B1 provides: 1) need set in advance error according to different geographical environments and priori data, it is the size of patent US 6313786B1 described TOA additional time delay error (BIAS), this is a loaded down with trivial details storehouse process of building, and its accuracy is difficult to guarantee; 2) use of numerous environmental data parameters causes the complicated of environmental data collecting; 3) be formed by stacking by two parts factor owing to the NLOS error: the one, the additional time delay error that reflection path is introduced; The 2nd, move behind the first footpath barycenter that the son footpath stack in the first footpath causes, and the correlation peak width that utilizes that this patent provides is estimated the method for TOA additional time delay error, the error that only is to use first footpath width to come estimator directly to superpose and introduce, be unable to estimate the TOA additional time delay error that produces by reflection and diffraction in principle, and be not suitable for the estimation error of NLOS channel therefore.

The applicant also once proposed a patent application, this patent application has provided a kind of location estimation method that can suppress the NLOS error, this method adopts following steps to realize suppressing the location estimation of NLOS error: the first step, adopt the NLOS recognition technology to pick out the framing signal that is in the NLOS state from the framing signal that location receiver receives; In second step, estimation is in the average and the variance of the TOA additional time delay error of the framing signal under the NLOS state; In the 3rd step, the NLOS error mean that used for second step obtained carries out zero-mean to TOA additional time delay error and corrects; In the 4th step, the NLOS error variance of using for second step obtained is adjusted the weighting matrix in the TOA location-estimation algorithm.But the shortcoming of this method is: 1) reduce in the factor of mobile station positioning accuracy the TOA additional time delay error under the NLOS channel, also has the TOA additional time delay error under LOS and the accurate LOS channel, and this invention only suppresses the TOA additional time delay error of the framing signal under the NLOS state, therefore, this method can't reach better position estimation accuracy; 2) estimated accuracy of the NLOS error estimation of this invention employing depends on the range resolution ratio of system, when system's range resolution ratio is low, can't reach high estimation error precision, thereby also just can't reach good error rectification effect.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of method of the TOA of inhibition additional time delay error, not only applicable to various channels, and can improve TOA additional time delay estimation error precision.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of method that suppresses TOA additional time delay error may further comprise the steps:

A. determine to obtain the required parameter of framing signal power time delay distribution, and according to determined parameter framing signal is searched for, the power time delay of obtaining framing signal distributes;

B. the footpath detection threshold that distributes of each power time delay of being obtained of determining step a, and according to determined thresholding respectively in the enterprising conduct judgement that distributes of corresponding power time delay, obtain the position in one or more footpath;

Whether the size of c. judging current sample coefficient of variation is greater than predefined sample coefficient of variation thresholding, if then current channel belongs to the second class channel, enters step e, otherwise current channel belongs to first kind channel, enters steps d;

D. estimate the average of TOA additional time delay error under the visual channel LOS, execution in step f;

E. estimate the average of TOA additional time delay error under the non-visible channel NLOS;

F. the TOA additional time delay error that steps d or step e are obtained suppresses.

This method further comprises: preestablish the sample coefficient of variation thresholding greater than 0.3, then the first kind channel described in the step c comprises LOS channel and accurate LOS channel, and the second class channel comprises the NLOS channel.

This method further comprises: preestablish the sample coefficient of variation thresholding less than 0.3, then the first kind channel described in the step c comprises the LOS channel, and the second class channel comprises accurate LOS channel and NLOS channel.

In the such scheme, steps d further comprises:

D1. according to the detected first footpath of step b amplitude, determine the desirable impulse response waveform of present receiving machine;

D2. path position and the steps d 1 determined desirable impulse response waveform that obtains according to step b obtains the barycenter hysteresis in first footpath, and calculates the estimated value of TOA additional time delay error under the LOS channel;

D3. judge whether present receiving machine has taked the noncoherent accumulation processing, if then the estimated value of the TOA additional time delay error that calculated of steps d 2 is the average of TOA additional time delay error; Otherwise, execution in step a M time, obtaining M power time delay distributes, again after obtaining a power time delay distribution at every turn, repeat steps d 1 to steps d 2, obtain the estimated value of a TOA additional time delay error, the estimated value to resulting M TOA additional time delay error averages then, obtains the average of TOA additional time delay error.

After obtaining TOA additional time delay error mean, steps d further comprises: according to the average of the TOA additional time delay error that is obtained, and the relation between TOA additional time delay error mean and TOA additional time delay error variance, estimate the variance of TOA additional time delay error.

In the such scheme, step e further comprises:

E1. one or more chip width behind the first footpath peak point that is obtained among the determining step b are as the window width that is used for the statistic window of NLOS estimation error;

E2. according to the position in every the footpath that is obtained among the step b, every time reference that is used for the footpath of NLOS estimation error in the statistic window of determining among the obtaining step e1;

E3. obtain step e1 in definite statistic window behind the time reference in every footpath, head footpath, utilize one or more footpath regularity of distribution of the TOA additional time delay error of its time reference point relatively, the average of estimation TOA additional time delay error.

After obtaining TOA additional time delay error mean, step e further comprises: according to the average of the TOA additional time delay error that is obtained, and the relation between TOA additional time delay error mean and TOA additional time delay error variance, estimate the variance of TOA additional time delay error.Wherein, described estimation TOA additional time delay error variance further comprises: the relation of utilizing TOA additional time delay error mean and variance earlier, obtain the variance of TOA additional time delay error mean, according to the relation of the multiple between variance of random variable before and after the average treatment in the statistical theory, calculate the variance of TOA additional time delay error again.

The described inhibition of step f TOA additional time delay error is: the estimated value that deducts the TOA additional time delay error mean that steps d or step e obtained from the TOA measuring amount.

The described inhibition of step f TOA additional time delay error specifically comprises: according to TOA location-estimation algorithm that is adopted or TOA+TDOA location-estimation algorithm, and the TOA additional time delay that adopts suppresses the definite weighting matrix form that will adjust of strategy, according to determined weighting matrix form, the TOA additional time delay error variance of using steps d or step e to estimate is revised the concrete element in the weighting matrix.

The described inhibition of step f TOA additional time delay error specifically comprises:

F1. from the TOA measuring amount, deduct the estimated value of the TOA additional time delay error mean that steps d or step e obtained, and with the input as location-estimation algorithm of the difference that obtained;

F2. according to the TOA location-estimation algorithm or the TOA+TDOA location-estimation algorithm of current employing, and the TOA additional time delay that adopts suppresses the definite weighting matrix form that will adjust of strategy, then according to determined weighting matrix form, the TOA additional time delay error variance of using steps d or step e to estimate is revised the concrete element in the weighting matrix.

Wherein, described TOA additional time delay inhibition strategy is: whether use error is corrected.

The method of inhibition TOA additional time delay error provided by the present invention, can accurately obtain under the LOS channel or under the accurate LOS channel or under the NLOS channel on the basis of TOA additional time delay error, the TOA additional time delay error that utilization estimates is carried out the correction of weighting matrix weights in rectification of TOA additional time delay error and the location-estimation algorithm, and then reaches the purpose that suppresses TOA additional time delay error.Because the present invention is when obtaining TOA additional time delay error, adopt different TOA additional time delay estimation error schemes at different classes of channel, and every kind of scheme all is based on, and the mechanism of production of such channel proposes, therefore can improve the estimated accuracy of TOA additional time delay error greatly, and then improve the inhibition effect of TOA additional time delay error.

As shown in Figure 2, Fig. 2 is cumulative distribution function (CDF) curve of TOA additional time delay error before and after correcting, and its abscissa is a TOA additional time delay error, is unit with the chip width.Heavy line among Fig. 2 is the CDF curve that carries out after TOA additional time delay error is corrected, and fine line is the CDF curve that carries out before TOA additional time delay error is corrected.Fig. 2 shows, after carrying out the rectification of TOA additional time delay error, TOA additional time delay error becomes the stochastic variable of approximate zero average, and the second order moment of the orign of rectification back error curve is less than the second order moment of the orign before correcting, and then explanation zero-mean rectification reduction influence of LOS error to position estimation accuracy.Simultaneously, fine line among Fig. 2 shows that 10% the TOA measuring amount of having an appointment is significantly less than zero, promptly less than negative 0.1 chip, this is because the TOA Measurement Algorithm that system adopts exists defective to cause, the existence of the TOA measuring amount that these are negative will reduce the performance that TOA additional time delay error suppresses algorithm, yet after the corresponding improvement of TOA Measurement Algorithm do, position estimation accuracy improvement amount shown in Figure 3 will be significantly increased.

The location estimation improvement in performance curve that Fig. 3 records for the field, the environment of this survey exists a spot of LOS channel and NLOS channel based on accurate LOS.The fine line that provides in the subgraph of Fig. 3 top represents to correct the CDF curve of front position estimated result, and the heavy line that provides in the subgraph of Fig. 3 top represents to correct back location estimation result's CDF curve; Position estimation error before the fine line that provides in the subgraph of Fig. 3 bottom is represented to correct, the position estimation error after the heavy line that provides in the subgraph of Fig. 3 bottom is represented to correct.Subgraph according to Fig. 3 top, with the correspondence position evaluated error is that 50 meters point is an example, as can be seen, CDF before CDF curve ratio after the rectification is corrected has taken parameter on trendline greatly about 10%, if do not have shown in the subgraph of Fig. 2 top because 10% the negative value that exists in the TOA measuring amount that causes of TOA Measurement Algorithm instability, the improvement amount can further improve; In the correspondence position evaluated error is 150 meters point, and the CDF after the rectification takes parameter on trendline and reached the positioning accuracy of FCC regulation, and obviously, the precision of location estimation has improved.

Description of drawings

Fig. 1 suppresses the realization flow figure of TOA additional time delay error for the present invention;

Fig. 2 is the CDF curve comparison diagram of TOA additional time delay error before and after correcting;

The location estimation improvement in performance curve synoptic diagram that Fig. 3 records for the field.

Embodiment

Core concept of the present invention is exactly: respectively at different classes of channel, obtain TOA additional time delay error according to different TOA additional time delay error estimations, carry out TOA additional time delay error according to the TOA additional time delay error of being obtained again and suppress.

The present invention proposes to estimate the method for TOA additional time delay error under the LOS channel respectively based on the analysis to TOA additional time delay error mechanism of production and distribution form under the LOS channel; Based on analysis, propose to estimate the method for TOA additional time delay error under the NLOS channel to TOA additional time delay error mechanism of production and distribution form under the NLOS channel.Among the present invention, it is very crucial to distinguish different classes of channel, usually big young pathbreaker LOS channel and the NLOS channel according to sample coefficient of variation separates, as for accurate LOS channel, because its mechanism of production and LOS channel are similar, use NLOS and numerically can be similar to, thus can be according to the difference of differentiating the channel type condition, accurate LOS and LOS or NLOS are divided into a class.

Following elder generation respectively to the mechanism of production of TOA additional time delay error under LOS channel and the NLOS channel, to the recognition principle of different channels and suppress TOA additional time delay error by principle and analyze.

At first, analyze the mechanism of production of LOS channel TOA additional time delay error:

For the analysis of TOA additional time delay error profile form under the LOS channel circumstance, need single distinguishable first footpath is decomposed into two son footpath P _S0And P _Sr, wherein, P _S0Representing the through composition in the first footpath, promptly is 0 son footpath with respect to LOS path TOA additional time delay error; P _SrP in the first footpath of expression _S0The composition that arrives through reflection path afterwards promptly is not 0 son footpath with respect to LOS path TOA additional time delay error.So, estimate that just in the process that TOA measures, the time of correlator output is exactly P in time delay _S0And P _SrCentroid position.Therefore, the distribution form of analysis TOA additional time delay error just is converted into and analyzes P _S0And P _SrThe distribution form of centroid position.

If t _LcBe the centroid position in the first footpath of LOS channel, t _SrBe P _SrThe position, p _S0Be P _S0Power, p _SrBe P _SrPower, when location receiver is not made noncoherent accumulation:

$t_{\mathrm{lc}}=\frac{t_{\mathrm{sr}}\&times;p_{\mathrm{<figure-callout\; id="0"\; label="sr\; p\; s"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">sr</figure-callout>}}}{p_s}---\left(1\right)$

Because p _SrConstitute by reflecting component, p is arranged _Sr＜＜p _S0, then formula (1) can be reduced to:

$t_{\mathrm{lc}}=\frac{t_{\mathrm{sr}}\&times;p_{\mathrm{<figure-callout\; id="0"\; label="sr\; p\; s"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">sr</figure-callout>}}}{p_s}=\left(\frac{p_{\mathrm{sr}}}{p_{s0}}\right)t_{\mathrm{sr}}---\left(2\right)$

In the formula (2), p _S0There is not decline, can be used as constant and handle.Since uniformity that scattering object distributes and separate character, according to central-limit theorem, son footpath P _SrThe t time of advent _SrShould be Normal Distribution, p _SrThe CHI2 that then obeys degree of freedom n=2 distributes, and this distribution is identical with Γ (α=1, β=2), and this exponential distribution Γ that distributes just (α=1, β)=expo (β).

Because t _SrAnd p _SrSeparate, can draw TOA error t under the LOS channel circumstance _LcProbability density function be:

$f_{t_{\mathrm{lc}}}(x,y)={\mathrm{<figure-callout\; id="0"\; label="p\; s"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">p</figure-callout>}}_s\&times;\mathrm{chi}2({\mathrm{<figure-callout\; id="0"\; label="p\; s"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">p</figure-callout>}}_s\&times;x,n)\&times;\mathrm{norm}(y,0.5,\mathrm{\&sigma;})---\left(3\right)$

In the formula (3), p _S0Be the power of wavefront component in the first footpath;

Be because the first footpath barycenter that amplitude fading causes changes x and because the Joint Distribution of the barycenter variable quantity y that the stack of reflection footpath causes.

About the edge distribution of x be index distribution Γ (α=1, β)=expo (β).

When system adopts k=n/2 noncoherent accumulation, the centroid position t in the footpath of the incoherent processing of process _LcBe the centroid position t in the footpath of the relevant output of single _LcAverage:

${\stackrel{\&OverBar;}{t}}_{\mathrm{lc}}=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{t}_{\mathrm{lc},i}---\left(4\right)$

Therefore, t _LcBe that (α=k's Γ β) distributes, and the average of Γ-distribution is α β, and variance is α β ², in view of the factor in the formula (4)

Existence, t _LcAverage and variance be:

E[t _lc]＝β

D[t _lc]＝β ² (5)

Under the condition of noncoherent accumulation, that directly measure is exactly E[t _Lc].

Under the LOS channel, the rule of TOA additional time delay estimation error utilization is: the reflected wave after the direct wave causes moving behind the barycenter of line of sight, moves behind this barycenter and show as the hysteresis of the peak point in footpath with respect to the starting point in footpath on the waveform of head footpath.

Under accurate LOS channel, cause in the factor of TOA additional time delay error, the first footpath barycenter that directly causes except the reflection under the LOS channel lags behind, and promptly outside Γ-distribution, also has the additional time delay component that produces in radio wave diffraction or the diffraction process, i.e. exponential distribution.Because these two components are separate, its distribution form is the convolution of Γ-distribution and exponential distribution, and its result still has the form of Γ-distribution.In the practical application, because under the accurate LOS channel, it is smaller to move component behind the barycenter that the additional time delay component that produces in radio wave diffraction or the diffraction process causes with respect to reflection footpath stack, can ignore the effect of this component, still adopt analytical method under the LOS channel to estimate TOA additional time delay error under the accurate LOS channel.

Under the NLOS environment, because first footpath and footpath thereafter all are formed by stacking by numerous sons footpath, this a little footpath is independent identically distributed, and according to the equally distributed hypothesis of scattering object, the intensity in this a little footpath all is suitable, and just the dereliction guide directly exists.Under this condition, the TOA additional time delay error t that the barycenter of reflector is introduced _RcSatisfy exponential distribution, so, according to central-limit theorem, the TOA additional time delay error t that the numerous sons footpath that is produced by reflector superposes and introduces _Sf, promptly with respect to t _RcTOA additional time delay error be to meet normal distribution.Therefore, the TOA additional time delay error t under the NLOS channel _n=t _Rc+ t _Sf, because t _RcAnd t _SfBe relatively independent stochastic variable, t _nDistribution be that index distributes and the convolution of normal distribution, as shown in Equation (6):

$f\left(t_n\right)=\mathrm{norm}(t_{\mathrm{sf}},\mathrm{\&mu;},\mathrm{\&sigma;})\&CircleTimes;\mathrm{expO}(x_{\mathrm{rc}},\mathrm{\&beta;})---\left(6\right)$

Because the signal interference ratio identical, each footpath of the scattering object density on each pairing space, footpath is identical on statistical significance, this has just determined not only have identical distribution form the time of advent in each footpath, and has an identical distributed constant, therefore, under the NLOS environment, first footpath and thereafter the TOA additional time delay error in some footpaths be that this is the basis of carrying out the NLOS estimation error with the random process that distributes.

Estimate first NLOS error directly for the drift rule of utilizing above-mentioned footpath, need to introduce the notion of the time reference (RTP, Reference Time Point) that is used for TOA additional time delay estimation error.The time reference in first footpath is: the TOA time location that calculates according to the LOS propagation path under the NLOS environment, the TOA additional time delay error of this position correspondence are zero; Certain footpath except head footpath, its time reference point is exactly: calculate the starting point of this footpath TOA additional time delay error, if should the footpath its time the reference point place occur, the TOA additional time delay error that means this footpath is zero.The foundation of determining the time reference in footpath is: the 1) range resolution ratio of system, range resolution ratio are determined that by system bandwidth for cdma system, its range resolution ratio is a chip; 2) under the NLOS environment, in a particular space scope, the probability that the footpath occurs on any position equates.

After introducing time reference, the TOA additional time delay errors table of first relative its time reference point RTP1 in footpath is shown t _n, the TOA additional time delay errors table of relative its time reference point RTP2 in second footpath is shown t _2l, the TOA additional time delay errors table of relative its time reference point RTPi in i footpath is shown t _IlWhen first footpath and i directly in confined space scope, when in hundreds of rice scope, occurring, t _n, t _2l... t _IlBe the approximately equalised random process of independent same distribution and distributed constant, this rule is the theoretical foundation that realizes TOA additional time delay error mean and variance estimation.Utilize this rule to carry out in the TOA measuring process, the formula of NLOS estimation error can be expressed as formula (7):

${\widehat{\stackrel{\&OverBar;}{t}}}_n\&ap;E\left[t_{2f}\right]\&ap;E\left[t_{3f}\right]\&ap;...\&ap;E\left[t_{\mathrm{if}}\right]---\left(7\right)$

In the formula (7),

The estimated value of the first footpath of expression TOA additional time delay error mean under NLOS.

Actual when using the described principle of formula (7), obtain the estimated value of the average of more first footpath TOA additional time delay error in order to utilize less measurement number of times, can adopt formula (8):

${\widehat{\stackrel{\&OverBar;}{t}}}_n\&ap;\left(E\right[t_{2f}]+E[t_{3f}]+...+E[t_{\mathrm{Nf}}\left]\right)/N---\left(8\right)$

In the formula (8), The estimated value of expression NLOS error; N is illustrated in same power time delay distribution and goes up the number in the footpath that is used for the NLOS estimation error of extracting, and does not wherein comprise first footpath.

As for identification to different channels, because LOS channel, accurate LOS channel and NLOS channel the decline intensity in footpath down are different, from the LOS channel to accurate LOS channel again to the NLOS channel, this declines to the process of degree of depth Rayleigh fading from Lay for one of the decline experience in footpath, according to this physical phenomenon, the applicant once proposed a kind of based on calculating sample, i.e. the NLOS recognition methods of the coefficient of variation of Jing amplitude or coefficient of dispersion: sample coefficient of variation σ/μ represents the average of the standard deviation of amplitude directly divided by sample magnitude.From the LOS channel to accurate LOS channel again to the NLOS channel, sample coefficient of variation σ/μ follows rule from small to large.The field is surveyed and is shown, the sample coefficient of variation σ/μ of typical NLOS channel is greater than 0.3.Certainly, also can adopt other method to realize NLOS identification, as: divided by the power of most powerful path thereafter, discern the NLOS channel with first footpath power according to the size of this ratio.

Inhibition for TOA additional time delay error is divided into two links: first link is to adopt the estimated value of TOA additional time delay error mean to carry out the error rectification, and the TOA additional time delay error that obtains zero-mean is corrected residual error; Second link is by the adjustment location-estimation algorithm, as: the weighting matrix of weighted least-squares algorithm for estimating further suppresses the influence that TOA additional time delay error is corrected residual error.

To location-estimation algorithm, the adjustment as weighting matrix in the weighted least-squares algorithm for estimating can be divided into: to the adjustment of weighting matrix in the TOA location estimation with to the adjustment of weighting matrix in the TOA+TDOA location-estimation algorithm.

The weighting matrix of the described TOA location-estimation algorithm that is used to adjust has the form shown in the formula (9):

$=Q_{\left(l\right)}+Q_{\left(n\right)}$

$={\left[\begin{array}{ccccc}{\mathrm{\&sigma;}}_1^2& 0& 0& .& 0\\ 0& {\mathrm{\&sigma;}}_2^2& 0& .& 0\\ 0& 0& {\mathrm{\&sigma;}}_3^2& .& 0\\ .& .& .& .& .\\ 0& 0& 0& .& {\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">M</figure-callout>}}^2\end{array}\right]}_{+}$

$\left[\begin{array}{ccccc}{\mathrm{\&sigma;}}_{\left(n\right)1}^2& 0& 0& .& 0\\ 0& {\mathrm{\&sigma;}}_{\left(n\right)2}^2& 0& .& 0\\ 0& 0& {\mathrm{\&sigma;}}_{\left(n\right)3}^2& .& 0\\ .& .& .& .& .\\ 0& 0& 0& .& {\mathrm{\&sigma;}}_{\left(n\right)M}^2\end{array}\right]---\left(9\right)$

Wherein,

$Q_{\left(l\right)}=\left[\begin{array}{ccccc}{\mathrm{\&sigma;}}_1^2& 0& 0& .& 0\\ 0& {\mathrm{\&sigma;}}_2^2& 0& .& 0\\ 0& 0& {\mathrm{\&sigma;}}_3^2& .& 0\\ .& .& .& .& .\\ 0& 0& 0& .& {\mathrm{\&sigma;}}_M^2\end{array}\right]---\left(10\right)$

In the following formula, Q _(l)Be systematic error N=[n under the LOS channel ₁n ₂N _M] ^TCovariance matrix, here, the position error when systematic error is meant no any TOA additional time delay error, N is the M n dimensional vector n, the average of N is zero, the covariance matrix Q of N _(l)Be M*M dimension symmetrical matrix.σ _i ²Under the LOS channel, promptly under no any TOA additional time delay error condition during position error, the covariance of TOA measure error.

$Q_{\left(n\right)}=\left[\begin{array}{ccccc}{\mathrm{\&sigma;}}_{\left(n\right)1}^2& 0& 0& .& 0\\ 0& {\mathrm{\&sigma;}}_{\left(n\right)2}^2& 0& .& 0\\ 0& 0& {\mathrm{\&sigma;}}_{\left(n\right)3}^2& .& 0\\ .& .& .& .& .\\ 0& 0& 0& .& {\mathrm{\&sigma;}}_{\left(n\right)M}^2\end{array}\right]---\left(11\right)$

Q _(n)Be the error n after the zero-mean rectification _{(n) i}, i.e. the M n dimensional vector n N that constitutes of the rectification residual error of TOA additional time delay error _(n)=[n _{(n) 1}, n _{(n) 2}N _{(n) M}] ^TCovariance matrix, N _(n)Average be zero, Q _(n)Be M*M dimension symmetrical matrix.

The citation form of the weighting matrix of the described TOA+TDOA location-estimation algorithm that is used to adjust is:

$Q_{\mathrm{toa}\_\mathrm{tdoa}}=E(n_{\mathrm{toa}\_\mathrm{tdoa}}\&CenterDot;n_{\mathrm{toa}\_\mathrm{tdoa}}^T)$

In the formula, Q _{Toa_tdoa}The weighting matrix of expression TOA+TDOA location-estimation algorithm; n _{Toa_tdoa}Expression has comprised the error vector of these two kinds of errors of TOA sum of errors TDOA error.Wherein, the TOA error comprises additional time delay sum of errors systematic measurement error, and the TDOA error comprises the difference and the systematic measurement error of additional time delay error.

In the TOA+TDOA location estimation, the measure error of TOA additional time delay error and system, promptly time delay is estimated and clock floats relation between the error that waits introducing, and the relation between TOA additional time delay error and the TDOA additional time delay error can be expressed as follows:

n _{ref_toa}＝n _{nlos_1}+n _{ref_toa_m}

n _{tdoa_21}＝n _{nlos_2}-n _{nlos_1}+n _{tdoa_21_m}

In the formula, n _{Ref_toa}The total error that comprises in the TOA measuring amount of expression reference base station, this error has comprised the intrinsic systematic error of TOA additional time delay sum of errors navigation system; n _{Nlos_i}Represent the TOA additional time delay error that comprises in the framing signal of i road; n _{Tdoa_j1}Represent total error of comprising in the TDOA measuring amount of j road framing signal with respect to first via signal, this error has comprised the difference and the intrinsic systematic error of navigation system of TOA additional time delay error; n _{Tdoa_j1_m}Represent the systematic error that comprises in the TDOA measuring amount of j road framing signal with respect to first via signal.Utilize the above-mentioned relation of error and through following steps, can obtain being used to shown in the formula (12) to adjust a kind of matrix form of the weighting matrix of TAO+TDOA location-estimation algorithm:

$n_{\mathrm{toa}\_\mathrm{tdoa}}=\left[\begin{array}{c}{n}_1\\ {\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\\ \&CenterDot;\\ n_n\end{array}\right]=H*V$

$H=\left[\begin{array}{cccccccc}1& 0& 0& 0& 1& 0& 0& 0\\ 0& 1& \&CenterDot;\&CenterDot;\&CenterDot;& 0& -1& 1& 0& 0\\ \&CenterDot;\&CenterDot;\&CenterDot;& 0& 1& \&CenterDot;\&CenterDot;\&CenterDot;& -1& \&CenterDot;\&CenterDot;\&CenterDot;& 1& \&CenterDot;\&CenterDot;\&CenterDot;\\ 0& 0& \&CenterDot;\&CenterDot;\&CenterDot;& 1& -1& 0& \&CenterDot;\&CenterDot;\&CenterDot;& 1\end{array}\right],$ $N=\left[\begin{array}{c}{n}_{\mathrm{ref}\_\mathrm{toa}}\\ n_{\mathrm{tdoa}\_21}\\ \&CenterDot;\&CenterDot;\&CenterDot;\\ n_{\mathrm{tdoa}\_n1}\\ n_{\mathrm{nlos}\_1}\\ n_{\mathrm{nlos}\_2}\\ \&CenterDot;\&CenterDot;\&CenterDot;\\ n_{\mathrm{nlos}\_n}\end{array}\right]$

$Q_{\mathrm{toa}\_\mathrm{tdoa}}=E(n_{\mathrm{toa}\_\mathrm{tdoa}}\&CenterDot;n_{\mathrm{toa}\_\mathrm{tdoa}}^T)=H\&CenterDot;C\&CenterDot;H^T$

$C=E(N*N^T)=\left[\begin{array}{cccc}{\mathrm{\&sigma;}}_1^2+{\mathrm{\&mu;}}_1^2& {\mathrm{\&mu;}}_1{\mathrm{\&mu;}}_2& {\mathrm{\&mu;}}_1{\mathrm{\&mu;}}_3& \&CenterDot;\&CenterDot;\&CenterDot;\\ {\mathrm{\&mu;}}_2{\mathrm{\&mu;}}_1& {\mathrm{\&sigma;}}_2^2+{\mathrm{\&mu;}}_2^2& {\mathrm{\&mu;}}_2{\mathrm{\&mu;}}_3& \&CenterDot;\&CenterDot;\&CenterDot;\\ \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;\\ \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="C0315619300261.png"\; state="\{\{state\}\}">m</figure-callout>}}^2+{\mathrm{\&mu;}}_m^2\end{array}\right]---\left(12\right)$

Wherein, μ _iAverage, the σ of i the error of expression column vector N _i ²The variance of i the error of expression column vector N.

The matrix form that formula (12) provides is applicable to the situation of not passing through the error correction of TOA additional time delay to the measuring amount of location-estimation algorithm input, after not passing through the error correction of TOA additional time delay to the measuring amount of location-estimation algorithm input, and μ _i=0, matrix (12) has the form of formula (13):

$C=E(N*N^T)=\left[\begin{array}{cccc}{\mathrm{\&sigma;}}_1^2& 0& \&CenterDot;\&CenterDot;\&CenterDot;& 0\\ 0& {\mathrm{\&sigma;}}_2^2& \&CenterDot;\&CenterDot;\&CenterDot;& 0\\ \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;& \&CenterDot;\&CenterDot;\&CenterDot;\\ 0& 0& \&CenterDot;\&CenterDot;\&CenterDot;& {\mathrm{\&sigma;}}_m^2\end{array}\right]---\left(13\right)$

In the formula (13), σ _i ²Expression TOA additional time delay error is corrected the variance of residual error.

In system realizes, at first according to the concrete location-estimation algorithm that adopts of system, i.e. TOA location estimation or TOA+TDOA location estimation; And the TOA additional time delay inhibition that system adopts is tactful, as: whether used the error rectification, any adjustment in the matrix form of determining formula (11), (12), (13) are provided.Then, utilize the variance of the TOA additional time delay error that obtains under aforesaid LOS channel, accurate LOS channel and the NLOS channel, value to each element in the selected matrix is adjusted, and so just can reach the effect that suppresses TOA additional time delay error, thereby improves the precision of location estimation.

Based on above-mentioned principle analysis, the method of inhibition TOA additional time delay error of the present invention, preestablish and divide the used sample coefficient of variation thresholding size of channel classification, according to sample coefficient of variation three kinds of channels are divided into two classes: if this sample coefficient of variation threshold value is greater than 0.3, as the sample coefficient of variation thresholding is 0.4, be a class with LOS channel and accurate LOS channel distribution then, the NLOS channel is divided into a class separately; If this sample coefficient of variation threshold value less than 0.3, is 0.2 as the sample coefficient of variation thresholding, be a class then with accurate LOS channel and NLOS channel distribution, the LOS channel is divided into a class separately.So, as shown in Figure 1, comprise the steps:

Step 101: according to the determined relevant parameter that is used to obtain the distribution of framing signal power time delay, framing signal is searched for, the power time delay of obtaining framing signal distributes.

This step is finished again in two steps:

The first step determines to obtain the framing signal power time delay needed relevant parameter that distributes.Here said relevant parameter mainly comprises: need gather the number of the pseudo noise code of its power time delay distribution simultaneously, corresponding a kind of power time delay of one of them pseudo noise code distributes; The number that needs same a kind of power time delay distribution of collection, the corresponding same pseudo noise code of this kind power time delay; Frequency acquisition to various power time delay distributions; The search window width of Multipath searching; Coherence length that adopts when gathering the power time delay distribution and noncoherent accumulation number of times etc.

Second step, according to the determined relevant parameter of the first step, all framing signals are carried out relevant search or matched filtering, the power time delay that obtains framing signal distributes.Wherein, framing signal can be the output from the cellular mobile station receiver, also can be the output from GPS or A-GPS receiver; Framing signal can be taken from the baseband signal of receiver, also can take from the intermediate-freuqncy signal of receiver.

Step 102: the footpath detection threshold that each power time delay that determining step 101 is obtained distributes, and according to determined threshold value respectively in the enterprising conduct judgement that distributes of corresponding power time delay, obtain the position in some footpaths.

In this step, determine that the footpath detection threshold that each power time delay distributes can have several different methods, the extraction of background noise determined that the footpath detection threshold is an example, determine that the specific implementation process of footpath detection threshold is such with basis:

1) extracts background noise, extract roughly earlier, accurately extract again.

Wherein, rough extraction can be divided into two kinds of situations again: realize the rough extraction of background noise by the method for rejecting several most powerful paths in power time delay distributes; Or extract background noise by using idle pseudo noise code to obtain the cross-correlation output signal.Idle pseudo noise code described here can be near the scrambler that the base station does not have use the cellular mobile station, also can be the framing signal sign indicating number of extrapolating in the gps satellite ephemeris that is in the following satellites transmits in horizon.

Accurately extract be meant rough extract background noise after, the background noise of rough extraction carried out parameter Estimation, as the average of estimating background noise comprising and standard deviation.According to the distribution form and the predetermined particular detection probability of the average that estimates, standard deviation, background noise, determine a rough footpath detection threshold THR_C again, utilize this THR_C from corresponding power time delay distributes, to detect a first footpath PATH1_C; Then, on this power time delay distributes, begin to open in beginning such interval, position, extract accurate background noise to search window from several chips before the PATH1_C.Here, the distribution form of background noise can be similar to and think x ²Distribute or normal distribution.

2) determine that each power time delay distribution is used for the noise gate that the footpath is detected.

Accurately extracting on the basis of background noise, estimating average, the standard deviation of background noise,, determining the final footpath detection threshold THR of each power time delay distribution then according to the distribution form and the predetermined particular detection probability of background noise.Equally, here, the distribution form of background noise can be x ²Distribute or normal distribution, when background noise is normal distribution,

THR＝Mu+k×Sigma

Wherein, Mu represents the average of background noise, and Sigma represents the standard deviation of background noise, and k is a weight coefficient, and the value of k detects the false alarm rate that requires by the footpath and decides.

3) carrying out the footpath detects.

According to each power time delay corresponding footpath detection threshold THR that distributes, the method by detection peak point on corresponding power time delay distributes realizes the footpath judgement, and the power time delay position of going up every peak point greater than footpath detection threshold THR that distributes is exactly position directly.

In step 102,, can after the position that detects the footpath,,, make interpolation and handle as the some footpaths after head footpath or the first footpath to interested footpath in order to improve the precision that the diameter time delay is estimated.It is a kind of interpolation algorithm that described interpolation is handled, be normally defined according to two given values and estimate median, and for example function or sequence, modal form is a linear interpolation, can adopt two fens interpolation methods.

Step 103:, judge the classification of current channel according to the size of current sample coefficient of variation.That is to say, adopt the judgement of NLOS channel identification method realization channel classification, the foundation of sample coefficient of variation as channel identification.If current sample coefficient of variation is greater than predefined sample coefficient of variation threshold value, then current channel is the category-B channel, enters step 104; Otherwise current channel is the category-A channel, enters step 106.

Specifically, be 0.4 if preestablish the sample coefficient of variation thresholding, then channel distribution is: LOS channel and accurate LOS channel are classified as category-A, the NLOS channel is classified as category-B, so, if the sample coefficient of variation of current channel is greater than 0.4, then be category-B, i.e. NLOS channel; Otherwise, just be judged to category-A, i.e. the accurate LOS channel of LOS/.According to the difference of channel classification judged result, enter different processing branches, just: the category-A channel adopts the TOA additional time delay estimation error algorithm under the LOS channel, and the category-B channel adopts the TOA additional time delay estimation error algorithm under the NLOS channel.

If preestablish the sample coefficient of variation thresholding is 0.2, and then channel distribution is: the LOS channel is classified as category-A, accurate LOS channel and NLOS channel are classified as category-B, so, if the sample coefficient of variation of current channel greater than 0.2, then is a category-B, promptly accurate LOS channel/NLOS channel; Otherwise, just be judged to category-A, i.e. the LOS channel.Corresponding with this channel category division, the category-A channel adopts the TOA additional time delay estimation error algorithm under the LOS channel, and accurate LOS in the category-B channel and NLOS channel all adopt the TOA additional time delay estimation error algorithm under the NLOS channel.

Step 104: carry out the estimation of TOA additional time delay error mean under the category-A channel.Specifically comprise:

Substep 41: according to the detected first footpath of step 102 amplitude, the desirable impulse response waveform of a location receiver transceiver channel of structure is as raised cosine waveform;

Substep 42: according to signal interference ratio or power, the detection threshold Thr in footpath and the desirable impulse response waveform that substep 41 is determined in the first footpath that obtains in the step 102, determine that is used for the thresholding THRC=C * Thr that the barycenter hysteresis is estimated, C gets certain value in 1～5;

Substep 43: first directly waveform is surveyed in the field of the correlator output that the calculating present receiving machine is followed the tracks of and the barycenter hysteresis is estimated the intersection point A of thresholding THRC, and calculates intersection point A time corresponding t _ACalculate desirable impulse response waveform and barycenter hysteresis and estimate the intersection points B of thresholding THRC, and calculate intersection points B time corresponding t _B

Substep 44: calculate the first footpath barycenter hysteresis that multipath is introduced under the LOS channel according to formula (14), thereby obtain the estimated value of TOA additional time delay error.

${\hat{t}}_L=t_A-t_B---\left(14\right)$

In the formula, The estimated value of TOA additional time delay under the expression LOS channel, unit is the chip width.

Substep 45:, judge whether current location receiver has taked the noncoherent accumulation processing according to the noncoherent accumulation number of times that step 101 is determined; If taked the noncoherent accumulation processing, promptly noncoherent accumulation number of times k is greater than 1, and what then substep 44 obtained is exactly the average of TOA additional time delay error, directly enters step 105; Handle if carry out noncoherent accumulation, then execution in step is 101M time, and wherein M obtains M power time delay and distributes greater than 1, obtain a power time delay distribution again at every turn after, just repeat the processing that substep 41 arrives substep 44, obtain one at every turn

Then to resulting M

Average, its result is exactly the average of TOA additional time delay error, and execution in step 105 then.

The TOA additional time delay error mean that step 104 is obtained can offer the variance that step 105 is used to estimate TOA additional time delay error, and this TOA additional time delay error mean can also offer the rectification that step 108 is used for TOA additional time delay error.

Step 105: carry out the estimation of TOA additional time delay error variance under the category-A channel.

According to the distribution form of TOA additional time delay error, as formula (3), and the average of the TOA additional time delay error that obtains of step 104, utilize the relation of average and variance under the specific distribution, as formula (5), calculate the variance of TOA additional time delay error, execution in step 108 then.

Step 106: carry out the estimation of TOA additional time delay error mean under the category-B channel.

This step both can use formula (7) to estimate the average of TOA additional time delay, also can use formula (8) to estimate the average of TOA additional time delay.The characteristics of using formula (8) are can be by less measurement number of times, as use the power time delay distribution measuring one time, obtain estimated value more accurately, carry out 107 then.

Wherein, the acquisition of every footpath time reference can be identified for the window width of the statistic window of NLOS estimation error earlier according to the position of the first footpath peak point that is obtained in the step 102; Then, according to the position in every the footpath that is obtained in the step 102, obtain every time reference that is used for the footpath of NLOS estimation error in the determined statistic window.Such as: the concave point of judging current front, footpath of wanting the acquisition time reference point to the time interval between the peak point in the footpath of concave point front whether smaller or equal to a chip width; If smaller or equal to a chip width, then with after the peak point in the footpath of concave point front apart from the position of a chip width of this peak point as the time reference in current footpath; Otherwise, directly with the time reference of concave point position as current footpath.

Step 107: carry out the estimation of TOA additional time delay error variance under the category-B channel.

The distribution form of the TOA additional time delay error that provides according to formula (6), TOA additional time delay error mean has exponential distribution as can be seen, if handle through noncoherent accumulation, TOA additional time delay error is exactly that gamma (GAMA) distributes.

This step utilization index distributes or the relation of Gamma distribution average and variance, obtains the variance of TOA additional time delay average, again according to the relation of the multiple between variance of random variable before and after the average treatment in the statistical theory, can draw the variance of TOA additional time delay.

Step 108: after obtaining the average or variance of TOA additional time delay error, acquisition TOA additional time delay error is suppressed, promptly carry out the rectification of TOA additional time delay error, or weighting matrix form in the location estimation is adjusted.

Substep 81: the average of the TOA additional time delay error that estimates according to step 104 or step 106, the TOA measuring amount is carried out the rectification of TOA additional time delay error, concrete grammar is: the estimated value that deducts TOA additional time delay error mean from the TOA measuring amount, the TOA measuring amount after correcting, promptly the TOA measuring amount deducts the input of the difference of TOA additional time delay error mean estimated value as location-estimation algorithm.

Substep 82: according to the concrete location-estimation algorithm that adopts of system, be to adopt the TOA location-estimation algorithm or adopt the TOA+TDOA location-estimation algorithm, and the TOA additional time delay that system adopts suppresses strategy, as: whether used the error rectification, any adjustment in the weighting matrix form of determining formula (11), (12), (13) are provided.Such as: when system adopts the TOA location estimation, the weighting matrix form that formula (11) provides is adjusted; When system adopts the TOA+TDOA location estimation, the weighting matrix form that formula (12) or formula (13) provide is adjusted.System described here is meant the navigation system of current employing.

Concrete form according to the definite weighting matrix of step 82, the variance of the TOA additional time delay error that use step 105 or step 107 estimate, concrete element in the weighting matrix is revised, suppress the bigger effect of TOA measuring amount in location estimation of TOA additional time delay error variance, thereby improve the precision of location estimation.Wherein, described concrete element has been revised multiple implementation method, such as: make the TOA additional time delay error variance in the TOA measuring amount of the value of respective element in the weighting matrix and this element correspondence keep a kind of proportional relationship.

In this step, substep 81 is that TOA additional time delay error is corrected, substep 82 is to the weighting matrix adjustment in the location-estimation algorithm, in actual applications, can use 82 liang of sub-steps of substep 81 and substep simultaneously, also can only use in this two sub-steps, can reach the effect that suppresses TOA additional time delay error equally.

In a word, the above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.

Claims (13)

1, a kind of method that suppresses TOA additional time delay error is characterized in that, may further comprise the steps:

A. determine to obtain the required parameter of framing signal power time delay distribution, and according to determined parameter framing signal is searched for, the power time delay of obtaining framing signal distributes;

B. the footpath detection threshold that distributes of each power time delay of being obtained of determining step a, and according to determined thresholding respectively in the enterprising conduct judgement that distributes of corresponding power time delay, obtain the position in one or more footpath;

Whether the size of c. judging current sample coefficient of variation is greater than predefined sample coefficient of variation thresholding, if then current channel belongs to the second class channel, enters step e, otherwise current channel belongs to first kind channel, enters steps d;

D. estimate the average of TOA additional time delay error under the visual channel LOS, execution in step f;

E. estimate the average of TOA additional time delay error under the non-visible channel NLOS;

F. the TOA additional time delay error that steps d or step e are obtained suppresses.

2, method according to claim 1, it is characterized in that, this method further comprises: preestablish the sample coefficient of variation thresholding greater than 0.3, then the first kind channel described in the step c comprises LOS channel and accurate LOS channel, and the second class channel comprises the NLOS channel.

3, method according to claim 1, it is characterized in that, this method further comprises: preestablish the sample coefficient of variation thresholding less than 0.3, then the first kind channel described in the step c comprises the LOS channel, and the second class channel comprises accurate LOS channel and NLOS channel.

4, method according to claim 1 is characterized in that, steps d further comprises:

D1. according to the detected first footpath of step b amplitude, determine the desirable impulse response waveform of present receiving machine;

D2. path position and the steps d 1 determined desirable impulse response waveform that obtains according to step b obtains the barycenter hysteresis in first footpath, and calculates the estimated value of TOA additional time delay error under the LOS channel;

D3. judge whether present receiving machine has taked the noncoherent accumulation processing, if then the estimated value of the TOA additional time delay error that calculated of steps d 2 is the average of TOA additional time delay error; Otherwise, execution in step aM time, obtaining M power time delay distributes, again after obtaining a power time delay distribution at every turn, repeat steps d 1 to steps d 2, obtain the estimated value of a TOA additional time delay error, the estimated value to resulting M TOA additional time delay error averages then, obtains the average of TOA additional time delay error.

5, method according to claim 4, it is characterized in that, after obtaining TOA additional time delay error mean, steps d further comprises: according to the average of the TOA additional time delay error that is obtained, and the relation between TOA additional time delay error mean and TOA additional time delay error variance, estimate the variance of TOA additional time delay error.

6, method according to claim 1 is characterized in that, step e further comprises:

E1. one or more chip width behind the first footpath peak point that is obtained among the determining step b are as the window width that is used for the statistic window of NLOS estimation error;

E2. according to the position in every the footpath that is obtained among the step b, every time reference that is used for the footpath of NLOS estimation error in the statistic window of determining among the obtaining step e1;

E3. obtain step e1 in definite statistic window behind the time reference in every footpath, head footpath, utilize one or more footpath regularity of distribution of the TOA additional time delay error of its time reference point relatively, the average of estimation TOA additional time delay error.

7, method according to claim 6, it is characterized in that, after obtaining TOA additional time delay error mean, step e further comprises: according to the average of the TOA additional time delay error that is obtained, and the relation between TOA additional time delay error mean and TOA additional time delay error variance, estimate the variance of TOA additional time delay error.

8, method according to claim 7, it is characterized in that, described estimation TOA additional time delay error variance further comprises: the relation of utilizing TOA additional time delay error mean and variance earlier, obtain the variance of TOA additional time delay error mean, according to the relation of the multiple between variance of random variable before and after the average treatment in the statistical theory, calculate the variance of TOA additional time delay error again.

9, method according to claim 1 is characterized in that, the described inhibition of step f TOA additional time delay error is: the estimated value that deducts the TOA additional time delay error mean that steps d or step e obtained from the TOA measuring amount.

10, according to claim 5,7 or 8 described methods, it is characterized in that, the described inhibition of step f TOA additional time delay error specifically comprises: according to TOA location-estimation algorithm that is adopted or TOA+TDOA location-estimation algorithm, and the TOA additional time delay that adopts suppresses the definite weighting matrix form that will adjust of strategy, according to determined weighting matrix form, the TOA additional time delay error variance of using steps d or step e to estimate is revised the concrete element in the weighting matrix.

11, method according to claim 10 is characterized in that, described TOA additional time delay suppresses strategy and is: whether use error is corrected.

According to claim 5,7 or 8 described methods, it is characterized in that 12, the described inhibition of step f TOA additional time delay error specifically comprises:

F1. from the TOA measuring amount, deduct the estimated value of the TOA additional time delay error mean that steps d or step e obtained, and with the input as location-estimation algorithm of the difference that obtained;

F2. according to the TOA location-estimation algorithm or the TOA+TDOA location-estimation algorithm of current employing, and the TOA additional time delay that adopts suppresses the definite weighting matrix form that will adjust of strategy, then according to determined weighting matrix form, the TOA additional time delay error variance of using steps d or step e to estimate is revised the concrete element in the weighting matrix.

13, method according to claim 12 is characterized in that, described TOA additional time delay suppresses strategy and is: whether use error is corrected.

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