CN101627317A - System and method for estimating positioning error within a WLAN-based positioning system - Google Patents

Abstract

The invention features a method of estimating an expected error of a position estimate for use in a WLAN positioning system that estimates the position of a WLAN- enabled device. The WLAN-enabled device receives signals transmitted by a WLAN access point in range of the WLAN-enabled device. The method estimates the position of the WLAN-enabled device based on the received signals from the WLAN access point in range of the WLAN enabled device. The method also estimates an expected error of the position estimate based on characteristics of the WLAN access point in range of the WLAN enabled device, wherein the expected error predicts a relative accuracy of the position estimate.

Description

Be used for estimating system and method based on the positioning error of the positioning system of WLAN

The cross reference of related application

The title that the application requires to be filed on November 7th, 2006 according to 35U.S.C. § 119 (e) is the U.S. Provisional Patent Application number 60/864 of Estimating Positioning Error for a WLAN Based PositioningSystem, 716 rights and interests are by with reference to it completely is combined in this.

The application relates to following U.S. Patent application, by reference its content is combined in this:

The title that is filed on October 28th, 2005 is the Application No. 11/261,987 of Method and Systemfor Building a Location Beacon Database;

The title that is filed on May 8th, 2006 is the Application No. 11/430,079 of Estimation Of Speedand Direction of Travel In A WLAN Positioning System;

The title that is filed on May 8th, 2006 is the Application No. 11/430,064 of Estimation of Speed andDirection of Travel In A WLAN Positioning System UsingMultiple Position Estimations;

The title that is filed on May 8th, 2006 is the Application No. 11/430,222 of Estimation of PositionUsing WLAN Access Point Radio Propagation CharacteristicsIn a WLAN Positioning System; And

The title that is filed on May 8th, 2006 is the Application No. 11/430,224 of Calculation of Qualityof WLAN Access Point Characterization for Use In a WLANPositioning System.

Technical field l

Present invention relates in general to evaluated error in based on the positioning system of WLAN, and more particularly, relate to and determine the error expected of use based on the estimated position of the mobile device of enabling WLAN of the positioning system of WLAN.

Background technology

Estimate to be based on the processing that the most probable value of target component is sought in the one group observable sampling relevant with target component.The accuracy of estimating may change based on the quality of the sampling that observes.The quality of quantitative estimation is one of main theme in the estimation theory, and in most of the cases, or even the problem more difficult than estimating target parameter.Satellite-based positioning system is one of early stage system that introduces for global location, and is called as GPS (GPS) for the same reason.In the GPS network, also determine the accuracy of estimating and report to the terminal user.Evaluated error in the GPS network is presented by different way.By considering that whole network determines estimation of error, and this precision that is called as level and vertical error reduces the factor (DOP).The DOP value is the indicator of error, and it also can be converted into rice be the error of unit.

Many research institutions are explored the positioning system based on WLAN of city scope, but they do not provide the anticipation error of location estimation.PlaceLab ( Www.placelab.comProject by Microsoft and Intel patronage), (ActiveCampus-SustainingEducational Communities through Mobile Technology technicalreport#CS2002-0714) has carried out most important research effort with the interschool positioning system of MIT to the ActiveCampus project of University of California, Santiago in this field.

Existence with the indoor positioning be some commerce of the WLAN positioning system of target provide product (referring to, Kavitha Muthukrishnan for example, Maria Lijding, Paul Havinga, Towards Smart Surroundings:Enabling Techniques and Technologiesfor Localization, Proceedings of the International Workshop onLocation and Context-Awareness (LoCA 2005) at Pervasive 2005, May 2005, and Hazas, M., Scott, J., Krumm, J.:Location-AwareComputing Comes of Age, IEEE Computer, 37 (2): 95-97, Feb 2,004 005, Pa005, Pages 350-362.) these systems are designed to solve the similar enterprises garden, assets in the controlled environment in hospital facility or shipping place and personnel follow the trail of.Typical example is to have the system that can monitor accurate position, emergency tender in hospital, thereby when heartbeat stops situation, medical worker's this equipment of location of can not losing time.The accuracy requirement of these operating positions is very harsh, requires the accuracy of 1-3 rice usually.These systems use its accuracy of the meticulous adjustment of various technology, comprise the detail location in every square feet in place is surveyed, so that measure the propagation of radio signal.They also need to continue network and connect, and exchange synchronizing information like that thereby access point and client radio can be similar to the working method of A-GPS.Though these systems become more reliable for the situation of indoor use, their deployment in any broader region fall flat.Can not carry out this type of essential detailed site survey to entire city, and can't look on the entire city zone existing these required degree of system and lasting communication channels 802.11 access points.The most important thing is, outdoor radio propagation and indoor wireless electric transmission fundamental difference, causing these indoor positioning technology almost is useless under the broader region situation.

Disposed 1,000,000 commerce and privately owned WLAN up to now, and this number is also increasing every day.Therefore, use the estimation of WLAN access point to enable the position of the mobile device of WLAN.

Summary of the invention

In one aspect, feature of the present invention is the method for the anticipation error estimated the estimated position being used for of using in a kind of WLAN positioning system of the position at the equipment of estimating to enable WLAN.The equipment of enabling WLAN receives the signal of being enabled the WLAN access point emission in the equipment range of WLAN by this.The signal that this method receives based on the WLAN access point in the range of the equipment of enabling WLAN estimates to enable the position of the equipment of WLAN.This method is also based on the anticipation error of the characteristic estimating location estimation of the WLAN access point in the range of the equipment of enabling WLAN, wherein the relative accuracy estimated of anticipation error predicted position.

In another aspect of the present invention, enable the location estimation of equipment of WLAN based on from the signal in the equipment range of enabling WLAN more than one WLAN access point.On the other hand, the anticipation error of location estimation is based on from the characteristic more than one WLAN access point in the equipment range of enabling WLAN.

In yet another aspect, the anticipation error of location estimation is based on the number of the access point of the position of the equipment that is used to estimate to enable WLAN.

In another aspect of the present invention, each WLAN access point has the signal coverage areas that is associated.The anticipation error of location estimation is based at least one of the signal coverage areas of the WLAN access point of the position of the equipment that is used for estimating enabling WLAN.

In another aspect of the present invention, the anticipation error of location estimation is based on the smallest signal coverage area of the WLAN access point of the position of the equipment that is used to estimate to enable WLAN.

In another aspect of the present invention, by determining to enable the geographic position of the equipment of WLAN from WLAN access point received signal, determine the standard deviation of overlay area based on determined geographic position, and estimate the overlay area of WLAN access point based on the standard deviation of overlay area, estimate the overlay area of each WLAN access point.

In one aspect of the invention, each WLAN access point has a geographic position, and the anticipation error of location estimation is based on the space distribution in the geographic position of the access point of the position of the equipment that is used to estimate to enable WLAN.Described space distribution is based on the distance between the geographic position of the WLAN access point of the position of the equipment that is used to estimate to enable WLAN.

In another aspect of the present invention, combined other location estimation of location estimation is used, so that at least one in position, speed and the direct of travel of the equipment of enabling WLAN of deriving, and gives the anticipation error that the weight position-based of location estimation is estimated.In one aspect, only when being lower than predetermined threshold value, just uses the anticipation error of location estimation this location estimation.In yet another aspect, at least one in described other location estimation is based on the signal of the reception of the WLAN access point in the equipment range of enabling WLAN.In others, provide in described other location estimation at least one by positioning system based on GPS.

In yet another aspect, feature of the present invention is the system of the anticipation error estimated the estimated position being used for of using in a kind of WLAN positioning system of the position at the equipment of estimating to enable WLAN.This system comprises: enable the equipment of WLAN, be used to receive the signal of being enabled the WLAN access point emission in the range of equipment of WLAN by this; The location estimation logic is used for estimating to enable based on the signal that the WLAN access point in the range of the equipment of enabling WLAN receives the position of the equipment of WLAN; With the estimation of error logic, be used for enabling the anticipation error of the described location estimation of characteristic estimating of the WLAN access point in the range of equipment of WLAN, wherein the relative accuracy estimated of anticipation error predicted position based on this.

Description of drawings

In the accompanying drawings:

Fig. 1 shows some embodiment of WLAN positioning system;

Fig. 2 shows the example in the mobile device of enabling WLAN and access point on every side and its respective coverage areas territory;

The space distribution that Fig. 3 shows detected WLAN access point is to the example of the influence of the accuracy of the location estimation of the mobile device of enabling WLAN; And

The number that Fig. 4 shows detected WLAN access point is to the example of the influence of the accuracy of the location estimation of the mobile device of enabling WLAN.

Embodiment

The error that the preferred embodiments of the present invention estimation is associated with the derivation position that is provided by the WLAN positioning system.The positioning system based on WLAN that can derive and the estimated position of the equipment of enabling WLAN is provided has been described in the patented claim of institute's combination.

The preferred embodiments of the present invention are determined and are upgraded the anticipation error based on the location estimation of the positioning system of WLAN that uses public and privately owned WLAN access point.(note, 802.11,802.11b, 802.11e, 802.11n and WiFi are the examples of wlan standard.) user's mobile device scans and detect public and privately owned WLAN access point periodically, and write down the characteristics of signals of each WLAN access point, for example, received signal intensity (RSS), time of arrival poor (TDOA) or with each WLAN access point corresponding time of arrival poor (TOA).In certain embodiments, mobile device oneself is determined the anticipation error of location estimation.In other embodiments, the result of WLAN access point sent to central location around mobile device will scan, and here, central server is determined anticipation error.

The anticipation error of WLAN location estimation can be used to quantize the quality of location estimation.In combination during a plurality of location estimation or in the time will making up with other location estimation technology (for example, the GPS location estimation) based on the location estimation of WLAN, this may be useful.When a series of location estimation of combination, the anticipation error of each location estimation can be used as weighting factor.For example, in order to increase the accuracy of single location estimation, a plurality of location estimation can be weighted on average.In this case, the anticipation error of each location estimation is used as the weight in the weighted average calculation.

In addition, can make up a series of location estimation, so that the advancing or carrying speed of derivation mobile device.When the such a series of location estimation of combination, the anticipation error of each estimation is used as the respective quality tolerance of this estimation, and this makes it possible to realize optimal combination to these a series of location estimation based on their quality.

For example, in the series of ten location estimation, suppose the low relatively anticipation error that all location estimation except the 7th location estimation have location estimation, and the 7th location estimation has high relatively anticipation error.When mobile device uses the speed of this serial location estimation derivation mobile device, mobile device can be got rid of the 7th location estimation in speed is determined, this is because its high relatively expected error value indicates this ad-hoc location to estimate to have low quality, and may be insecure therefore.

The anticipation error of location estimation also can be used for determining the anticipation error after the block position estimated result.For example, if the location estimation result is used to definite gait of march, then make up the anticipation error of each location estimation, so that determine the evaluated error of gait of march.

The disclosed technology of submitting to before some embodiment of the present invention is based upon of application, on the system and method, include but not limited to that all being filed in the title on October 28th, 2005 is the U.S. Patent application No.11/261 of Location Beacon Database, 848, title is the U.S. Patent application No.11/261 of Server for Updating Location Beacon Database, 898, title is the U.S. Patent application No.11/261 of Method and System for Building a LocationBeacon Database, 987, with title be the pass state patented claim No.11/261 of Location-Based Services that Choose Location Algorithms Based onNumber of Detected Access Points Within Range of User Device, 988, and include but not limited to that all being filed in the title on May 8th, 2006 is the U.S. Patent application No.11/430 of Calculation of Quality of WLAN Access PointCharacterization for Use in a WLAN Positioning System, 224, with title be the U.S. Patent application No.11/430 of Estimation of Position Using WLANAccess Point Radio Propagation Characteristics in a WLANPositioning System, 222, by reference its complete content is combined in this.The concrete approach of collecting high quality location data for the WLAN access point has been instructed in these applications, thereby these data can be used for service based on the location, so as to determine to utilize this service the equipment of enabling WLAN the geographic position and use the technology of described locator data estimating system customer location.Yet technology of the present invention is not limited to disclosed system and method in the patented claim of institute's combination.Therefore, though may be helpful, can not think that this is to understand present embodiment or the present invention is necessary with reference to these systems and application.

Fig. 1 has described WLAN positioning system (WPS).This positioning system comprises the positioning software [103] that resides on the subscriber equipment [101].In the specific objective geographic area,, there is the fixed wireless access point [102] that uses control/shared channel broadcast singal broadcast message everywhere.Client devices monitors broadcast singal or asks its emission by probe requests thereby.Each access point comprises the unique hardware identifier that is called as MAC Address.The signal beacon that client computer positioning software 103 receives from 802.11 access points 102 in the range, and use the geographic position of determining subscriber equipment 101 from the characteristic of signal beacon.These characteristics comprise the MAC Address of access point and arrive the signal intensity of client devices.Access point in 802.11 access points that client software will observe and the reference database of its access point [104] compares, the access point reference database also can reside in or not reside on this equipment (promptly, in certain embodiments, reference database can be positioned at a distance).Reference database comprises the geographic position and the power profile of the estimation of all access points that collection system compiled.Can be from representative compiles from the reading of the power of the signal of each position the generation power profile.Use these known position and power profile, client software is determined the relative position of subscriber equipment [101], and determines its geographic coordinate with the form of latitude and longitude readings.Then these readings are offered application, such as companion's finder, local search Web website, fleet management system and E911 service based on the location.

The preferred embodiments of the present invention can be used to enable the equipment of WLAN, so that determine and upgrade the anticipation error of location estimation.For example, technology can be bonded in the logic of positioning software [103] of the equipment of enabling WLAN that embeds Fig. 1 according to an embodiment of the invention.

Under the guidance of one embodiment of the present of invention, estimate to enable the anticipation error of location estimation of the mobile device of WLAN based on the overlay area of all access points that are used to locate the mobile device of enabling WLAN.In other words, if consider all detected access points, then use the signal foot prints (or overlay area) of detected access point to determine the anticipation error of location estimation.In an exemplary enforcement, the smallest coverage area of the access point of the position of the mobile device by being used to estimate to enable WLAN defines the anticipation error of location estimation.Therefore, this method is used for estimating based on the smallest coverage area in the access point of the terminal user's of the positioning system of WLAN position based on searching.Anticipation error is directly related with the smallest coverage of detected WLAN access point.If represent anticipation error, and use C with e _MinRepresent smallest coverage, then this error can followingly be written as the function of smallest coverage:

e∝f(C _min)

Symbol ∝ means directly related.An example of this function is as follows:

e＝K _cC _min

Parameter K _cBe that value with smallest coverage area is scaled in proportion with rice be the constant of the actual error of unit.Parameter K _cTo be the error of unit square metre to be that the smallest coverage of unit is converted to rice.By considering the enough samplings in the whole overlay area and seeking actual error and C _MinValue rule of thumb finds parameter K _cCan be by comparing definite actual error by estimated position and the known location that the WLAN positioning system provides.

The overlay area of WLAN access point or footprint are defined as such zone, and the mobile device of wherein enabling WLAN can detect this specific access point.Comprise the target geographical area of many access points and the received signal intensity (RSS) of record known position by system scan, search out the overlay area of access point.When considering all samplings of given access point, use the indicator of the standard deviation of RSS sampling location as the overlay area size of access point.In certain embodiments, consider all RSS samplings.In other embodiments, if RSS is lower than given threshold value, then ignore some RSS sampling.If represent the RSS sampling sum of access point with M, and with (x _i, y _i) represent the relevant position of RSS sampling i, then the standard deviation of overlay area is by following calculating:

$\mathrm{\σ}=\sqrt{{\mathrm{\σ}}_x^2+{\mathrm{\σ}}_y^2},$

Wherein, σ _xAnd σ _yBe respectively that x is gone up in all M samplings _iAnd y _iStandard deviation.

Fig. 2 shows the example of the mobile device of enabling WLAN and the WLAN access point around it.In Fig. 2, user [201] detects the WLAN access point [202a-d] in the range, and by using detected WLAN access point as its position of reference point estimation.Access point [202a-d] in the range has different footprint size [203a-d].Smallest coverage [204] by detected access point [202a-d] defines evaluated error.For example, if the radius of the overlay area [203a] of access point [202a] is 100 meters, it is 100 meters then with the corresponding maximum estimated error in user's [201] position.

Under the guidance of other embodiments of the invention, spatially how to distribute based on detected access point, that is, and the distance between the geographic position of detected access point, the anticipation error that the estimated position is estimated.Figure 3 illustrates the example of the space distribution of detected access point to the influence of position estimation error.Fig. 3 shows mobile device [301] and the detected access point [302] of enabling WLAN and the mobile device [303] and detected access point [304] of enabling WLAN.The estimated position of mobile device [301] and [303] is shown with circle [305] and [306] respectively.The figure shows with the mobile device [303] of space distribution and compare, have the less evaluated error of the mobile device [301] of the space distribution of less relatively detected access point with relatively large detected access point.Can be by the standard deviation of the position of access point in X-axis and Y-axis _SxAnd σ _SyMeasure the space distribution of access point, and the following then gross space distribution standard deviation of finding out:

${\mathrm{\σ}}_s=\sqrt{{{\mathrm{\σ}}_{\mathrm{sx}}}^2+{{\mathrm{\σ}}_{\mathrm{sy}}}^2}$

Anticipation error is directly relevant with the standard deviation of this space distribution.Therefore,

e∝f(σ _s).

An example of above-mentioned function is as follows:

e＝K _sσ _s ²

Parameter K _sBe that output valve is scaled in proportion with rice is the constant of the error of unit.Parameter K _sWill be square metre being that square being converted to rice of standard deviation of unit is the error of unit.By considering the enough samplings in the whole overlay area and seeking actual error and standard variance value, rule of thumb find parameter K _sBy using above-mentioned technique computes with the error of rice as unit.

Under the guidance of other embodiments of the invention, estimate the anticipation error of the mobile device of enabling WLAN in the WLAN positioning system based on the number of detected access point.As shown in Figure 4, anticipation error reduces along with the increase of detected access point number.Fig. 4 shows two mobile device [401] and [403] of enabling WLAN that have detected access point [402] and [404] respectively and have estimated position [405] and [406] respectively.This illustrates because to be used to estimate to enable the number of access point of position of mobile device [403] of WLAN more, and the anticipation error of location estimation of mobile device [403] of enabling WLAN is lower.Therefore, anticipation error is relevant with the inverse of the number of detected access point.If the N representative is used for the number of the detected access point of locating end-user, then anticipation error can be written as by following:

$e\∝f\left(\frac{1}{N}\right)$

An example of above-mentioned function is as follows:

$e=K_N\frac{1}{\sqrt{N}}$

Parameter K _NBe that output with equation is scaled in proportion with rice be the constant of the error of unit.With regard to its unit, parameter K _NUnit is a rice.By considering the enough samplings in the whole overlay area and seeking actual error and N value, rule of thumb find parameter K _NUse above-mentioned technique computes with the error of rice as unit.

Under the guidance of other embodiments of the invention,, estimate the anticipation error of the mobile device of enabling WLAN in the WLAN positioning system based on a plurality of correlation parameters of combination and error.Three parameters relevant with the anticipation error of location estimation are as follows: the smallest coverage C of (1) detected access point _Min, square root/one of the number of (2) detected access point,

(3) space distribution of detected access point square, σ _s ²

Above-mentioned parameter is relevant with anticipation error, but with regard to absolute value, they have different dynamic ranges.In order to make up them, its absolute value of standardization at first.By parameter is realized the standardization of parameter divided by the standard deviation of their dynamic range.Dynamic range is the minimum and maximum absolute value of all access points in the given overlay area.

Standardized parameter can be by average simply, or can be according to the accuracy of each parameter prediction anticipation error with their weightings and average then, and this is called weighted mean.More wish error prediction accuracy according to error component to each error component weighting, and this is the optimum combination method.Next step of weighted average method is the tolerance of each parameter of definition measuring error prediction accuracy.

The correlativity of each parameter and error is measured the accuracy of the error prediction of certain errors method of estimation.These related coefficients are used in weighted average calculation each method weighting.Related coefficient is a statistical parameter, and by the actual error of searching location estimation and estimated value and definite then related coefficient of searching parameter, each parameter is determined in the sampling of enough numbers of based target geographic area globally.Therefore, related coefficient shows the statistic correlation of estimated parameter and evaluated error, and the quality of a sampling of parameter definitely is not shown.For example, the example that the position is determined may have very little evaluated error, but the smallest coverage area of this detected access point may be relatively large.In this example, the smallest coverage area of detected access point is not the good indicator of error, but it still by with the identical related coefficient weighting of other sampling.Therefore, the average weighted anticipation error of use error parameter is written as follows:

$e\∝[C_c\frac{C_{\min }}{\mathrm{\σ}\left(C_{\min }\right)}+C_N\frac{\sqrt{1/N}}{\mathrm{\σ}\left(\sqrt{1/N}\right)}+C_s\frac{{{\mathrm{\σ}}_s}^2}{\mathrm{\σ}\left({{\mathrm{\σ}}_s}^2\right)}]\×\frac{1}{(C_c+C_N+C_s)}$

In the superincumbent equation, the standard deviation operational symbol is shown with σ, and respectively with C _c, C _NAnd C _sRelated coefficient C is shown _Min, N and σ _sRelated coefficient does not have unit.By considering the enough samplings in the whole overlay area and relatively expecting the sum of errors actual error rule of thumb to find the parameter correlation coefficient for each sampling.

Under the guidance of other embodiments of the invention, finding from the parameter relevant with anticipation error with rice is the anticipation error of the location estimation of unit.Suppose to exist the parameter relevant with anticipation error, being mapped to what find by the distribution with error parameter during scanning target geographical area is the error of the actual range of unit with rice, and finding with rice is the evaluated error of unit.Therefore, if use d _eRepresentative is the error of unit with rice, and it can be used as mapping result and find, and can be by following calculating:

$d_e=\left(\frac{e-\stackrel{\‾}{e}}{\mathrm{\σ}\left(e\right)}\right)\mathrm{\σ}\left(d_e\right)+{\stackrel{\‾}{d}}_e$

Note, the mean value of stochastic process is shown, and the standard deviation operational symbol is shown with σ with the horizontal line on the variable.These parameter distributions by in the sampling of considering to compile from whole overlay area rule of thumb find d _eAverage and standard deviation with e.The standard deviation of parameter and the example of mean value are as follows:

σ(C _min)＝2.7546

$\mathrm{\σ}\left(\sqrt{1/N}\right)=0.1721$

σ(σ _s ²)＝3.8707×10 ^-7

e＝1.5613

σ _e＝0.7458

d _e＝38.1m

${\mathrm{\σ}}_{d_e}=29.0m$

Note the standard deviation of the space distribution of determining detected access point based on the latitude and the longitude of access point.

An example of related coefficient is as follows:

0.30≤C _c，C _N，C _s≤0.37

Should be appreciated that scope of the present invention is not limited to the foregoing description, but by appended claim definition; And these claims will comprise the modification of describing content and improvement.

Claims (22)

1. method that in the WLAN positioning system of the position of the equipment of estimating to enable WLAN, is used for the anticipation error estimated the estimated position, this method comprises:

The equipment of enabling WLAN receives the signal of being enabled the WLAN access point emission in the range of equipment of WLAN by this;

The signal that receives based on the WLAN access point in the range of the equipment of enabling WLAN from this estimates that this enables the position of the equipment of WLAN; And

Based on this anticipation error of enabling the described location estimation of characteristic estimating of the WLAN access point in the range of equipment of WLAN, wherein said anticipation error forecasting institute rheme is put the relative accuracy of estimation.

2. the method for claim 1, wherein to the estimation of the position of the equipment of enabling WLAN based on the signal in the range of the equipment of enabling WLAN from this more than a WLAN access point.

3. the method for claim 1, wherein to the estimation of the anticipation error of location estimation based on the characteristic in the range of the equipment of enabling WLAN from this more than a WLAN access point.

4. the method for claim 1 is wherein to the estimation of the anticipation error of the location estimation number based on the access point of the position of the equipment that is used to estimate that this enables WLAN.

5. method as claimed in claim 4, wherein the number of the anticipation error of location estimation and the access point of the position of the equipment that is used to estimate that this enables WLAN square is inversely proportional to.

6. the method for claim 1, wherein each WLAN access point has the signal coverage areas that is associated, and at least one based on the signal coverage areas of the WLAN access point of the position of the equipment that is used for estimating that this enables WLAN of the estimation of the anticipation error of location estimation.

7. method as claimed in claim 6 is wherein to the estimation of the anticipation error of the location estimation smallest signal coverage area based on the WLAN access point of the position of the equipment that is used to estimate that this enables WLAN.

8. method as claimed in claim 7, wherein the anticipation error of location estimation is directly proportional with the smallest signal coverage area of the WLAN access point of the position of the equipment that is used to estimate that this enables WLAN.

9. method as claimed in claim 6, wherein estimate the overlay area of each WLAN access point by the method that may further comprise the steps:

Determine to enable the geographic position of the equipment reception of WLAN from the signal of this WLAN access point;

Determine the standard deviation of described overlay area based on determined geographic position; And

Estimate the overlay area of this WLAN access point based on the standard deviation of described overlay area.

10. the method for claim 1, wherein each WLAN access point has a geographic position, and to the estimation of the anticipation error of the location estimation space distribution based on the geographic position of the access point of the position of the equipment that is used to estimate that this enables WLAN, described space distribution is based on the distance between the geographic position of the WLAN access point of the position of the equipment that is used to estimate that this enables WLAN.

11. method as claimed in claim 10, wherein the standard deviation of the anticipation error of location estimation and the space distribution in the geographic position of the access point of the position of the equipment that is used to estimate that this enables WLAN square is directly proportional.

12. the method for claim 1, the equipment of the wherein said WLAN of enabling is estimated the anticipation error of described location estimation.

13. the method for claim 1, wherein server system is estimated the anticipation error of described location estimation.

14. the method for claim 1, wherein said location estimation is used in combination with other location estimation, this enables in position, speed and the direct of travel of the equipment of WLAN at least one so that derive, and gives the anticipation error of the weight of described location estimation based on described location estimation.

15. method as claimed in claim 14 is wherein only just used described location estimation when the anticipation error of described location estimation is lower than predetermined threshold value.

16. method as claimed in claim 14, the signal that at least one in wherein said other location estimation receives based on the WLAN access point in the range of the equipment of enabling WLAN from this.

17. method as claimed in claim 14 wherein provides in described other location estimation at least one by the positioning system based on GPS.

18. the method for claim 1, wherein the estimation of the anticipation error of location estimation is based on first expected error value of estimating according to the number of the access point of the position of the equipment that is used to estimate that this enables WLAN, second expected error value of estimating according to the smallest signal coverage area of the WLAN access point of the position of the equipment that is used to estimate that this enables WLAN and the weighted mean of hoping error amount according to the third phase that the space distribution in the geographic position of the access point of the position of the equipment that is used to estimate that this enables WLAN is estimated, described space distribution is based on the distance between the geographic position of the WLAN access point of the position of the equipment that is used to estimate that this enables WLAN.

19. method as claimed in claim 18 wherein hopes the error amount weighting for first, second and the third phase according to corresponding related coefficient, each related coefficient is measured the accuracy of its corresponding anticipation error value prediction actual error.

20. a system that is used for the anticipation error estimated the estimated position in the WLAN positioning system of the position of the equipment of estimating to enable WLAN, this is used to estimate that the system of anticipation error comprises:

Enable the equipment of WLAN, be used to receive the signal of enabling the WLAN access point emission in the range of equipment of WLAN by this;

The location estimation logic is used for estimating that based on the signal that the WLAN access point in the range of the equipment of enabling WLAN from this receives this enables the position of the equipment of WLAN; And

The estimation of error logic is used for the anticipation error of enabling the described location estimation of characteristic estimating of the WLAN access point in the range of equipment of WLAN based on this, and wherein said anticipation error forecasting institute rheme is put the relative accuracy of estimation.

21. system as claimed in claim 20 wherein carries out described location estimation logic on the described equipment of enabling WLAN.

22. method as claimed in claim 20 is wherein carried out described location estimation logic on server system.

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