KR101583981B1 - Method and device for gathering wlan signal based on high-speed driving vehicles - Google Patents

Abstract

An apparatus and method for collecting WLAN signals in the present invention are disclosed. In particular, a WLAN signal collecting apparatus for collecting signals of a WLAN AP, comprising: a WLAN signal collecting unit for scanning a WLAN channel and collecting the detected WLAN signals to generate a WLAN AP list, based on a Global Positioning System (GPS) A position measurement unit for determining WLAN signal acquisition position information by correcting the estimated position information of the WLAN signal acquisition device based on information detected by an INS (Inertial Navigation System) sensor and DMI (Distance Measuring Instrument) measurement information, And a synchronization unit for synchronizing the time at which the WLAN signal acquisition position information is determined and the WLAN AP list and the WLAN signal acquisition position information.

Description

≪ Desc / Clms Page number 1 > METHOD AND DEVICE FOR GATHERING WLAN SIGNAL BASED ON HIGH-SPEED DRIVING VEHICLES < RTI ID =

The present invention relates to a wireless LAN (WLAN) signal collecting apparatus and method, and more particularly, to a wireless local area network (WLAN) signal collecting apparatus and method for installing a WLAN signal acquisition Apparatus and method.

Location Based Service (LBS) refers to application systems and services that locate and utilize objects based on wired and mobile communication networks. In other words, it is a technology that provides various services to the user by grasping the position of the mobile phone etc. in real time using the positioning technology.

Recently, a technique for detecting a radio signal broadcasted from a WLAN Access Point (AP) and detecting and providing a position of a terminal based on a parameter value such as a signal intensity of the detected signal is attracting attention. Positioning technology using triangulation method, RF fingerprint method, received signal strength indicator (RSSI) transmitted from neighboring AP, and positioning technique using probabilistic modeling method using WLAN AP information have been developed have. In order to perform positioning of the terminal through such positioning technology, accurate and effective location of the WLAN AP should be collected and analyzed.

The conventional WLAN AP collecting method has an error of 0.7 to 1 m on average by determining the collection point by utilizing only the GPS receiver when estimating the collection position, and when the GPS signal is not good like the urban area, a position error of 50 m or more occurs.

In addition, the conventional WLAN signal collection is performed by collecting WLAN signals of all channels simultaneously. This method causes a delay time of about 1.5 seconds because of the necessity of scanning all the channels. When the speed is 40 km / h, the position error is 16.5 m, which is not suitable for high speed acquisition.

Korean Registered Patent No. 10-1099151, registered on December 20, 2011 (name: location cover database, server, location marker database construction method, and location based service using this)

It is an object of the present invention to provide a WLAN signal acquisition apparatus and method for determining an accurate acquisition position through various positioning sensors as well as GPS in order to collect WLAN signals in high-speed moving and GPS reception failure environments.

Also, a WLAN signal collecting apparatus and method for shortening a period of collecting Wi-Fi signals to collect WLAN signals in a high-speed moving environment are proposed.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to one aspect of the present invention, there is provided a WLAN signal collecting apparatus for collecting signals of a WLAN AP, comprising: a WLAN signal collecting unit for scanning a WLAN channel to collect a detected WLAN signal to generate a WLAN AP list; a Global Positioning System (GPS) (WLAN) signal acquisition location information based on the information detected by the INS (Inertial Navigation System) sensor and the DMI (Distance Measuring Instrument) measurement information, And a synchronization unit for synchronizing the collection time of the WLAN signal and the WLAN signal collection location information with the WLAN AP list and the WLAN signal collection location information.

Another aspect of the present invention is a method of collecting a signal of a WLAN AP, comprising the steps of: a WLAN signal acquisition device scanning a WLAN channel to collect a detected WLAN signal to generate a WLAN AP list; Based on the information detected by the INS (Inertial Navigation System) sensor and the DMI (Distance Measuring Instrument) measurement information, based on the position information of the WLAN signal collecting device estimated based on the Global Positioning System (GPS) And a step of synchronizing the time at which the WLAN signal acquisition position and the WLAN signal acquisition position information are determined to integrate with the WLAN AP list and the WLAN signal acquisition position information.

Preferably, the WLAN signal can be collected only in the WLAN channel preset independently for each WLAN signal receiving unit.

Preferably, in order to synchronize the time at which the WLAN signal acquisition location information is determined with the acquisition time of the WLAN signal, the format of the time at which the WLAN signal acquisition location information is determined is set to 0: 00: Can be recalculated and converted.

Preferably, the format of the collection time of the WLAN signal may be changed to the GPS reference time in order to synchronize the time at which the WLAN signal acquisition time and the WLAN signal acquisition location information are determined.

Preferably, the information of the mobile WLAN AP may be filtered in the WLAN AP list before the time of collection of the WLAN signal and the time of the WLAN signal acquisition location information are synchronized.

According to the embodiment of the present invention, it is possible to precisely and precisely determine the position using sensors such as INS, DMI, etc. even in an environment where GPS position error and reception are poor.

Also, according to the embodiment of the present invention, it is possible to shorten the collection period of the WLAN signal, minimize the position error caused by the high-speed movement, and collect accurate WLAN signal data.

Also, according to the embodiment of the present invention, it is possible to accurately and economically collect a DB required for positional positioning such as fingerprint positioning, and is effective when constructing a DB on a large scale or nationwide basis.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the technical features of the invention.
1 is a diagram illustrating a WLAN signal acquisition system in accordance with an embodiment of the present invention.
2 is a diagram illustrating a WLAN signal acquisition method in accordance with an embodiment of the present invention.
FIG. 3 is a diagram for explaining a conventional channel scanning operation and a channel scanning operation according to an embodiment of the present invention.
FIG. 4 is a view for explaining a comparison of a conventional channel scanning operation and a collection delay error distance generated according to the channel scanning operation according to an embodiment of the present invention.
5 is a diagram for explaining an effect of a WLAN signal collecting apparatus according to an embodiment of the present invention in comparison with a conventional WLAN signal collecting system.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or may be shown in block diagram form, centering on the core functionality of each structure and device, to avoid obscuring the concepts of the present invention.

Throughout the specification, when an element is referred to as "comprising" or " including ", it is meant that the element does not exclude other elements, do. Also, the terms " part, "" module," and " module ", etc. in the specification mean a unit for processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software have. Also, the terms " a or ", "one "," the ", and the like are synonyms in the context of describing the invention (particularly in the context of the following claims) May be used in a sense including both singular and plural, unless the context clearly dictates otherwise.

The specific terminology used in the following description is provided to aid understanding of the present invention, and the use of such specific terminology may be changed into other forms without departing from the technical idea of the present invention.

1 is a diagram illustrating a WLAN signal acquisition system in accordance with an embodiment of the present invention.

The configuration of the WLAN signal collecting apparatus 200 shown in FIG. 1 shows functionally functioning functional elements, and any or more of the configurations may be physically integrated or separated from each other.

Referring to FIG. 1, the WLAN signal collecting system according to the present invention efficiently collects WLAN signals to construct a wireless signal map database for WLAN-based positioning for an outdoor area, Based service server 200 and a WLAN signal collecting apparatus 100 as a system for generating a list.

The WLAN AP information is used as the base information for the WLAN-based positioning and includes information on an access point (AP), a WLAN signal transmitted from the AP (for example, a beacon signal broadcast from the AP) Information and / or WLAN signal reception time information. For example, a service set identifier (SSID) of the AP, a medium access control address (MAC address) of the AP, a received signal strength indicator (RSSI) of the WLAN signal transmitted from the AP, And the like.

Here, the AP is a logical entity including a MAC layer and a physical layer interface for a wireless medium. The AP is a distributed entity (DS) through a wireless medium to an associated STA (Associated Station) Distribution System). The AP may be referred to as a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), a femto BS (femto BS)

The location based service (LBS) server 100 collects the location of the WLAN AP from the WLAN signal collecting apparatus 100 and constructs a radio map DB. Based on the constructed radio map DB, Quot; server " Also, various services can be provided to the user based on the location information of the user terminal obtained by performing the WLAN-based positioning.

The WLAN signal collecting apparatus 200 refers to a device for measuring the position of a corresponding WLAN AP through GPS (Global Positioning System) position information and WLAN AP signal information of the WLAN signal collecting apparatus 200. The WLAN signal collecting apparatus 200 may be mounted on a vehicle or the like and continuously receives a Global Positioning System (GPS) signal during the movement of the mounted vehicle. Upon detecting the WLAN signal transmitted from the WLAN AP, The location of the corresponding WLAN AP is determined based on the GPS location information of the device 200 and the detected WLAN AP information. Then, the location information of the determined WLAN AP is periodically or event-based aperiodically transmitted to the location-based service server 100.

The WLAN signal collecting apparatus 200 includes a position measuring unit 210 for measuring a position of the WLAN signal collecting apparatus 200, that is, a WLAN signal collecting position, a signal collecting unit 210 for collecting signals of the WLAN AP and generating WLAN AP information A synchronization unit 230 for generating WLAN AP position information by synchronizing the time of the position measurement unit 210 and the WLAN signal acquisition unit 220 for more accurate positional positioning of the WLAN AP, And a communication unit (240) for transmitting the location information to the location-based service server (100).

More specifically, the position measuring unit 210 includes a GPS signal receiving unit 211 for determining the absolute position of the WLAN signal collecting apparatus 200, An INS sensor unit 213 and a DMI measurement unit 215. The INS sensor unit 213 and the DMI measurement unit 215 are connected to an INS And a GPS / INS integration unit 217 for determining the more accurate acquisition location for the WLAN signal.

The GPS signal receiving unit 211 periodically receives the GPS signal and measures the GPS position information based on the GPS received signal. In addition, the GPS signal receiving unit 211 includes an atomic clock and also records the GPS signal reception time together with the GPS position information. That is, the GPS / INS integration unit 217, which will be described later, can acquire GPS signal reception time information from the GPS signal reception unit 211. [

The INS sensor unit 213 determines a bearing reference in the gyroscope and performs a function of obtaining a movement displacement using an accelerometer. For example, if the initial position of the WLAN signal collecting apparatus 200 is input, the position and speed of the WLAN signal collecting apparatus 200 can be continuously calculated and grasped even if the WLAN signal collecting apparatus 200 moves.

The DMI measuring unit 215 measures the distance traveled by the WLAN signal collecting apparatus 200. The DMI measuring unit 215 may measure the traveling distance of the vehicle mounted on the wheels of the vehicle or the like and equipped with the WLAN signal collecting apparatus 200.

The GPS / INS integration unit 217 integrates information measured by the GPS signal reception unit 211, the INS sensor unit 213, and the DMI measurement unit 215 to determine a collecting position of a final WLAN signal . That is, the position of the final WLAN signal collecting apparatus 200 is estimated. Based on the GPS position information of the WLAN signal collecting apparatus 200 measured by the GPS signal receiving unit 211, through the information measured by the INS sensor unit 213 and the DMI measuring unit 215, thereby collecting the final WLAN signal The position can be estimated.

The collected position information of the WLAN signal estimated by the GPS / INS integration unit 217 is estimated based on the GPS signal reception time. For example, when a GPS signal is received every one second, the location information of the WLAN signal estimated in units of one second is generated. That is, the acquisition location information of each WLAN signal has its own GPS time. The GPS / INS integration unit 217 integrates the GPS position information of the estimated WLAN signal and the GPS position information of the WLAN signal (that is, the GPS position information and the GPS time information of the WLAN signal) ).

In this manner, by integrating the information measured by the INS sensor unit 213 and the DMI measurement unit 215 in addition to the GPS-based position information via the GPS signal receiving unit 211, high-accuracy / high- Can be estimated. Further, in order to collect the WLAN signal in an environment where the GPS signal reception is poor, it is also possible to determine an accurate collection position through various positioning sensors (i.e., the INS sensor unit 213 and the DMI measurement unit 215) have.

More specifically, the WLAN signal collecting unit 220 includes a GPS signal receiving unit 221 for obtaining a GPS signal receiving time, a WLAN signal receiving unit 223 for receiving a signal of the WLAN AP, A channel management unit 225 for managing a channel for each WLAN signal reception unit 223 in order to minimize a WLAN signal collection delay time in the WLAN signal reception unit 223, And a GPS / WLAN integration unit 227 for integrating the WLAN AP list collected by the WLAN signal reception unit 223.

The GPS signal receiving unit 221 periodically receives GPS signals. In addition, the GPS signal receiving unit 221 records the GPS signal reception time including the atomic clock. That is, the GPS / WLAN integration unit 227, which will be described later, can acquire the GPS signal reception time information from the GPS signal reception unit 221. [ Although the GPS signal receiving units 211 and 221 are shown as separate functional units in FIG. 1, they may be physically implemented as a single module.

The WLAN signal receiving unit 223 performs a scanning operation on the operation channel in the frequency band of the WLAN signal, and receives the WLAN signal transmitted from the WLAN AP. The WLAN signal receiving unit 223 may include a plurality of WLAN signal receiving units 223 and may perform scanning only on the channels set by the channel managing unit 225. [ The WLAN signal receiving unit 223 acquires information on the WLAN AP through the received WLAN signal. As described above, the WLAN AP information may include the SSID of the AP that transmitted the received WLAN signal, the MAC address of the AP, the RSSI of the WLAN signal, the reception time information of the WLAN signal, and the like.

The channel management unit 225 manages an operation channel to be scanned for each WLAN signal receiving unit 223. That is, in order to minimize the WLAN signal collection delay time, the channel management unit 225 previously determines an operation channel to be scanned by each WLAN signal receiving unit 223.

The WLAN signal acquisition delay time must be minimized in order to collect the WLAN signal at a high speed in a collecting vehicle that moves fast (i.e., the vehicle on which the WLAN signal collecting apparatus 200 is mounted). In the present invention, since each WLAN signal receiver 223 receives a signal for each channel selected by the channel manager 225, the WLAN signal acquisition delay time for acquiring WLAN AP information can be minimized. A detailed description of a method for minimizing the WLAN signal acquisition delay time error will be given later.

The GPS / WLAN integration unit 227 integrates the WLAN AP list obtained through the WLAN signal reception unit 223 with the GPS time acquired through the GPS signal collection unit 221. For example, the GPS / WLAN integrating unit 227 may acquire the WLAN AP list at a predetermined period and may integrate the GPS time acquired through the GPS signal collecting unit 221 at the time of acquiring the WLAN AP list . The GPS / WLAN integration unit 227 transmits the WLAN AP list and the GPS time information (i.e., the WLAN AP list and the GPS time information), which is a reference of the generation time of the WLAN AP list, to the synchronization unit 230.

More specifically, the synchronization unit 230 includes a PreFix filter 231 for filtering the WLAN AP, a GPS time conversion unit 233 for adjusting the heterogeneous GPS time, a position measurement unit 210, And a data integrating unit 235 for integrating the information acquired from the WLAN signal collecting unit 220 in time synchronization.

The PreFix filter 231 performs filtering on unnecessary WLAN AP information in the WLAN AP list and GPS time information acquired through the WLAN signal collecting unit 220.

When acquiring WLAN AP data using the WLAN signal collecting unit 220, the mobile WLAN AP information can be collected together. This mobile WLAN AP information significantly reduces the accuracy in constructing the radio map DB and increases the data processing time, which is an essential factor for efficient programming. The PreFix filter 231 is used as a method for removing such unnecessary mobile WLAN AP information.

The PreFix filter 231 can perform filtering on the SSID item or the MAC address in the collected WLAN AP information. For example, when performing filtering based on the SSID, predefine the characters to be filtered, numbers, symbols, etc., read the SSID from the WLAN AP information, and write the predefined letters, numbers, symbols, If a specific character, number, symbol, or the like is included in the comparison, it is determined that the AP is a mobile WLAN AP and can be automatically filtered.

The GPS time conversion unit 233 performs a function of converting the GPS time format to integrate the GPS time and the WLAN signal reception time in the data integration unit 235 described later.

The atomic clock included in the GPS signal receiving units 211 and 221 is set to the GPS time reference. The GPS time is expressed by using the week number, day number, and sec (sec) instead of expressing the time in the commonly used year, month, and day. In order to match the time format with the reception (or collection) time of the WLAN signal in the data integration unit 235 described later, the GPS time conversion unit 233 converts the date and time into AM Recalculate the GSP time in units of seconds and store it again. That is, the GPS time conversion unit 233 recalculates and stores the GPS time information included in the GPS position information and the GPS position information of the WLAN signal acquired from the position measurement unit 210. Also, the WLAN AP list acquired from the WLAN signal collecting unit 220 and the GPS time information included in the GPS time information are recalculated and stored.

The data integration unit 235 constructs the collection location information and the GPS time information database (DB) of the WLAN signal acquired by the location measurement unit 210 and transmits the WLAN AP list acquired by the WLAN signal collection unit 220 Build a GPS time information DB. Then, it integrates the collection location information of the WLAN signal, the GPS time information DB, the WLAN AP list, and the GPS time information DB.

When integrating the WLAN signal acquisition position information, the GPS time information DB, the WLAN AP list, and the GPS time information DB, the data integration unit 235 can integrate the DB based on the GPS time information included in each DB .

The collected position information of the WLAN signal and the GPS time information included in the GPS time information DB have a value one-to-one matched with the collected position information of the WLAN signal. On the other hand, the GPS time information included in the WLAN AP list and the GPS time information DB has GPS time information according to the generation time of the WLAN AP list. The collection location information of the WLAN signal, the GPS time information DB, the WLAN AP list, and the GPS time information DB can be divided into a predetermined time unit, and a DB can be constructed. Here, the data integration unit 235 integrates the WLAN AP list including the GPS time information, which is the same as the GPS time information included in the specific time unit of the WLAN AP list and the GPS time information DB, It is possible to integrate with the unit of time of the GPS location information and GPS time information DB.

Thus, when the DB is integrated based on the GPS time information, the WLAN signal reception time is also converted into the GPS time to match the WLAN signal acquisition location information with the WLAN AP list.

More specifically, the receiving time of the WLAN signal received through the WLAN signal receiving unit 223 is recorded together with the internal system time and the UTM reference time only when the WLAN signal is received for the first time, and then the reception of the WLAN signal The time is recorded. The data integrating unit 235 calculates the UTM time in units of seconds after adding the time difference of 9 time in order to set the received UTM time according to the Korean time. That is, add the difference of the system time recorded when receiving the WLAN signal every time from the system time at which the first WLAN signal was received to the modified UTM time (= difference of system time + UTM standard + 9) The WLAN signal reception time is changed and rewritten. By changing the time, the rewritten WLAN AP list and the GPS time information DB are compared with the collection location information of the WLAN signal and the GPS time information DB to generate the final WLAN signal collection location information and the WLAN AP list. That is, since the information obtained by the position measuring unit 210 and the information obtained by the WLAN signal collecting unit 220 are the same in time unit, the location information of the WLAN signal acquired at the same time and the WLAN AP list are stored in a new (I.e., a collection location information of the WLAN signal and a WLAN AP list). The data generated through this process includes the information of the neighboring WLAN APs at the relevant time and the precise location when collecting the information.

Then, the data integration unit 235 transmits the generated location information of the WLAN signal and the WLAN AP list to the location-based service server 100 through the communication unit 240.

The communication unit 240 may include one or more modules for enabling the WLAN signal collecting apparatus 200 to perform wired / wireless communication with the location-based service server 100. As a communication method at this time, a wireless communication method such as mobile communication conforming to the 3GPP communication standard, wireless LAN (WLAN), WiMAX, HSDPA (High Speed Downlink Packet Access), Ethernet, xDSL (ADSL, VDSL) A wired communication method such as Hybrid Fiber Coaxial Cable (HFC), Fiber To The Curb (FTTC), and Fiber To The Home (FTTH) may be used, or a combination thereof may be used.

Also, the communication unit 240 may be included in the WLAN signal receiving unit 223 described above. In other words, the WLAN signal receiving unit 223 includes one or more modules that enable communication with the location-based service server 100 via the WLAN AP in a WLAN wireless communication manner, in which case the communication unit 240 is a separate functional unit The WLAN signal collecting apparatus 200 may communicate with the location based service server 100 via the WLAN signal receiving unit 223. [

2 is a diagram illustrating a WLAN signal acquisition method in accordance with an embodiment of the present invention.

Referring to FIG. 2, the WLAN signal collecting unit 220 transmits the integrated WLAN AP list and GPS time information to the PreFix filter 231 (S201).

The PreFix filter 231 filters unnecessary WLAN APs from the WLAN AP list and GPS time information acquired from the WLAN signal collection unit 220 (S203). Here, the PreFix filter 231 may predefine a character, a number, a symbol, and the like to be filtered with respect to the SSID of the WLAN AP, and delete the WLAN AP having the SSID including predefined characters, numbers, symbols, have.

Then, the PreFix filter 231 transmits the filtered WLAN AP list and GPS time information to the GPS time conversion unit 233 (S205).

The GPS time conversion unit 233 converts the GPS time format from the filtered WLAN AP list and the GPS time information acquired from the PreFix filter 231 (S207). As described above, the GPS time is expressed by using the week number, the day number, and the second (sec), but the GPS time conversion unit 233 converts the GPS time format to AM 0:00: 000 and converts the date and time into seconds.

Then, the GPS time conversion unit 233 transfers the filtered WLAN AP list and the converted GPS time information to the data integration unit 235 (S209).

The data integration unit 235 performs an interpolation on the reception time of the WLAN signal from the filtered WLAN AP list acquired from the GPS time conversion unit 233 and the converted GPS time information (S211). As described above, since the recorded format of the reception time of the WLAN signal is different from the GSP time format, the data integration unit 235 changes the format of the reception time of the WLAN signal to the GPS standard time format. The data integrating unit 235 adds the difference of the system time recorded when the WLAN signal is received each time the system time at which the first WLAN signal was received to the modified UTM time (= difference in system time + UTM reference time + 9) Change the reception time of WLAN signal by GPS standard.

The position measuring unit 210 transmits the estimated position information of the WLAN signal and the GPS time information to the GPS time converting unit 233 (S213).

The GPS time conversion unit 233 converts the GPS time format from the WLAN signal acquisition position information and the GPS time information acquired from the position measurement unit 210 (S215). As described above, the GPS time is expressed by using the week number, the day number, and the second (sec), but the GPS time conversion unit 233 converts the GPS time format to AM 0:00: 000 and converts the date and time into seconds.

Then, the GPS time conversion unit 233 transfers the WLAN signal collection position information and the converted GPS time information to the data integration unit 235 (S217).

The data integration unit 235 integrates the filtered WLAN AP list and the converted GPS time information acquired from the GPS time conversion unit 233 and the WLAN signal collection location information and the converted GPS time information into the time synchronization (S219). In this way, by performing the time synchronization, the data integration unit 235 generates and stores the collection location information of the WLAN signal and the WLAN AP list as a new data format. Then, the data integration unit 235 periodically or non-periodically transmits the generated location information of the WLAN signal and the WLAN AP list to the location-based service server 100.

2 illustrates a process of transferring data from the WLAN signal collecting unit 220 to the synchronization unit 230 and then transferring data from the position measurement unit 210 to the synchronization unit 230. However, It is needless to say that the temporal relationship can be changed. That is, the temporal relationship between steps S213 and S217 may be changed from step S201 to step S211.

FIG. 3 is a diagram for explaining a conventional channel scanning operation and a channel scanning operation according to an embodiment of the present invention.

FIG. 3 (a) illustrates a WLAN channel configuration, FIG. 3 (b) illustrates a channel scanning operation performed in an existing WLAN signal acquisition device, and FIG. 3 (c) FIG. 3 illustrates a channel scanning operation performed in a WLAN signal collecting apparatus according to an embodiment of the present invention. FIG.

As shown in FIG. 3 (a), the center frequencies of the WLAN operating channels are 2.412, 2.417, ... , 2.484, and is assumed to be composed of 14 operating channels with a channel bandwidth of 22 MHz per channel, and it is assumed that the WLAN signal collecting apparatus collects WLAN signals in a total of 13 operating channels.

As shown in FIG. 3 (b), in a conventional WLAN signal collecting apparatus, a single WLAN receiver is used to detect all the WLAN signals of the WLAN APs in the 13 operating channels, and then the detected signals are recorded. In addition, even if a plurality of WLAN receivers are used, a WLAN signal in 13 operation channels is detected per one WLAN receiver. Therefore, a collection delay error of about 1.2 seconds occurs from the time of starting the collection of the WLAN signal until the recording time of the WLAN signal.

However, since the WLAN signal collecting apparatus is usually mounted on a vehicle and collects WLAN AP information at a high speed, it is necessary to minimize such a collection delay error. That is, in order to minimize the collection delay error, the time for starting the collection of the WLAN signal and the delay time of the recording time should be shortened.

Therefore, according to the present invention, 13 WLAN receivers are allocated to 13 channels, unlike a method of collecting WLAN signals of all channels using a conventional WLAN receiver. That is, each WLAN receiver is configured to receive a wireless WLAN signal in a frequency region allocated for each channel through a channel management unit. In other words, unlike the conventional method of detecting a WLAN signal in 13 operating channels per one WLAN receiver even when a plurality of WLAN receivers are used as described above, only 13 WLAN receivers, .

Thus, if only one operating channel detects a WLAN signal for each WLAN receiver, only a delay time of about 0.2 seconds occurs from the collecting time of the WLAN to the recording time. That is, since each WLAN receiver scans and records only one channel in comparison with the delay time of scanning and recording all 13 channels, it has the effect of reducing the 6 times delay time.

Shortening of the delay time is extremely important in a method of scanning a WLAN signal while proceeding at a high speed, which will be described with reference to FIG.

4 is a diagram for explaining a comparison of a conventional channel scanning operation and a collection delay error distance generated according to the channel scanning operation according to an embodiment of the present invention.

FIG. 4A illustrates a collection delay error distance generated according to a conventional channel scanning operation, and FIG. 4B illustrates a collection delay error distance generated according to a channel scanning operation according to an embodiment of the present invention. . Hereinafter, description will be made on the assumption of the same situation as in Fig.

As described above, the channel scanning operation in the conventional WLAN signal collecting apparatus scans all 13 operation channels and records the detected signals, so that a collection delay error of about 1.2 seconds occurs from the acquisition start time to the recording time. When the WLAN signal acquisition system moves at 40 km / h, a collection delay error distance of about 11 m (= 40 km / h * collection delay time) occurs due to a collection delay error of about 1.2 seconds. Therefore, as described above, since the WLAN list and the WLAN signal collection position are mapped at the same time on the basis of the GPS time, the WLAN signal collection position generates an error distance of about 11 m from the position where the actual WLAN signal is detected.

On the other hand, the channel scanning operation in the WLAN signal collecting apparatus according to the present invention scans only one operation channel and records the detected signal, so that a collection delay error of about 0.2 seconds occurs from the acquisition start time to the recording time. When the WLAN signal collector moves to 40 km / h, a collection delay error distance of about 2 m (= 40 km / h * collection delay time) occurs due to a collection delay error of about 0.2 seconds. That is, the WLAN signal acquisition position generates an error distance of about 2 m from the position where the actual WLAN signal is detected, and the error distance is significantly reduced as compared with the conventional method.

The WLAN signal collecting apparatus 200 according to the present invention may include a plurality of WLAN signal receiving units 223 and the channel managing unit 225 may include a plurality of WLAN signal receiving units 223, Set the WLAN channel for scanning the signal. Here, one WLAN channel may be set in one WLAN signal receiving unit 223, but one or more WLAN channels may be independently set in each WLAN signal receiving unit 223.

5 is a diagram for explaining an effect of a WLAN signal collecting apparatus according to an embodiment of the present invention in comparison with a conventional WLAN signal collecting system.

FIG. 5A illustrates a conventional WLAN signal collection method, and FIG. 5B illustrates a WLAN signal collection device WLAN signal collection method according to an embodiment of the present invention. 5 (a) and 5 (b) represent points of WLAN signal collection estimated using GPS signals, and points indicated by red indicate points of WLAN signal collection finally determined by correcting or correcting the points.

According to the conventional method, only the GPS signals mounted on the vehicle are used to determine the WLAN signal acquisition point. Therefore, in an area where reception sensitivity of the GPS signal is poor, it is inevitable that an inaccurate WLAN signal acquisition point is estimated. In such an incorrectly estimated WLAN signal acquisition point, it is necessary to arbitrarily correct the error (the blue line in (a) of FIG. 5) and eventually an inaccurate WLAN AP location DB can not be generated.

On the other hand, according to the WLAN signal acquisition method according to an embodiment of the present invention, by utilizing an INS sensor (i.e., an accelerometer, a gyroscope) and a DMI measurement system in addition to a GPS signal, a WLAN signal acquisition point determined through a GPS receiver is supplemented . In FIG. 5 (b), a dotted line indicated by green indicates a WLAN signal acquisition position corrected using information measured by the INS sensor and the DMI measurement system in addition to the GPS signal. Therefore, it is possible to estimate the accurate WLAN signal acquisition position even in a region where reception sensitivity of the GPS signal is poor, and furthermore, to provide highly accurate WLAN signal acquisition position information and to construct a high quality WLAN location DB.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like which performs the functions or operations described above. The software code can be stored in memory and driven by the processor. The memory is located inside or outside the processor, and can exchange data with the processor by various means already known.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the foregoing detailed description is to be considered in all respects illustrative and not restrictive. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

A radio map DB for positioning a user terminal based on WLAN can be constructed through the WLAN signal collection method according to the present invention, thereby providing various location based services to the user.

100: Location-based service server 200: WLAN signal collecting device
210: position measuring unit 211: GPS signal receiving unit
213: INS sensor unit 215: DMI measurement unit
217: GPS / INS integration unit 220: WLAN signal collection unit
221: GPS signal receiving unit 223: WLAN signal receiving unit
225: Channel management unit 227: GPS / WLAN integration unit
230: synchronization unit 231: PreFix filter
233: GPS time conversion unit 235: Data integration unit
240:

Claims (10)

A WLAN signal collecting apparatus for collecting signals of a wireless local area network (WLAN) access point (AP)
A WLAN signal collector for scanning the WLAN channel and collecting the detected WLAN signal to generate a WLAN AP list;
The position information of the WLAN signal collecting apparatus estimated based on a GPS (Global Positioning System) signal is corrected based on information detected through an INS (Inertial Navigation System) sensor and DMI (Distance Measuring Instrument) A position measurement unit for determining the collection position information; And
And a synchronization unit for synchronizing the collection time of the WLAN signal with a time at which the WLAN signal collection location information is determined and integrating the collection time with the WLAN AP list and the WLAN signal collection location information,
The synchronization unit includes a filtering unit for filtering information of the mobile WLAN AP using a MAC (Medium Access Control) address and an SCID (Service Set Identifier) in the WLAN AP list;
The WLAN signal acquisition time is changed to the GPS standard time after adding the difference of the system time recorded when the WLAN signal is received at the collection time of the WLAN signal to the collection time of the WLAN signal, A time conversion unit for recalculating and converting the date and time in seconds based on 0:00:00 000 seconds to synchronize the collection time of the WLAN signal with the time at which the WLAN signal collection location information is determined; And
And a data integration unit for converting the WLAN AP list acquired at the synchronized time and the WLAN signal acquisition location information determined at the synchronized time into a data format for transmission to a location based server. The apparatus of claim 1, wherein the WLAN signal collecting unit includes a plurality of WLAN signal receiving units,
And collecting the WLAN signal only in a predetermined WLAN channel independently for each WLAN signal receiving unit. delete delete delete A method of collecting signals of a wireless local area network (WLAN) access point (AP)
Scanning a WLAN channel to collect a detected WLAN signal to generate a WLAN AP list;
The WLAN signal collecting device may calculate position information of the WLAN signal collecting device estimated based on a Global Positioning System (GPS) signal based on information detected through an INS (Inertial Navigation System) sensor and DMI (Distance Measuring Instrument) To determine the WLAN signal acquisition position information;
Filtering the information of the mobile WLAN AP using a Medium Access Control (MAC) address and a Service Set Identifier (SCID) in the WLAN AP list;
The WLAN signal collecting apparatus changes the system time difference recorded when the WLAN signal is received at the collection time of the WLAN signal to the collection time of the WLAN signal and then changes to the GPS reference time, Recalculating and converting the date and time in units of seconds on the basis of 0:00:00, 000 seconds in the morning every day to synchronize the collection time of the WLAN signal with the time when the WLAN signal collection location information is determined; And
And converting the WLAN signal collection location information determined at the synchronized time into the data format for transmission to the location based server, the WLAN signal collection device comprising: Way. The method according to claim 6,
And collecting the WLAN signal only in a predetermined WLAN channel independently for each of a plurality of WLAN signal receiving units included in the WLAN signal collecting apparatus. delete delete delete

Images