KR20040101662A - Apparatus and method for providing location information - Google Patents

Abstract

PURPOSE: An apparatus for providing location information is provided to enable a wireless terminal, located at a shadow area where it is impossible to receive a satellite signal from the GPS(Global Positioning System) satellite, to exactly measure the present location by comprising a signal processing unit for generating a satellite signal and a modulating unit for generating a virtual GPS satellite signal by modulating the satellite signal, and then transmitting the signal to the wireless terminal. CONSTITUTION: A CDMA network(140) comprises a BTS(Base Transceiver Station)(130), a GPSOne server(132), and a satellite antenna(134). A master repeater(150) amplifies a signal transmitted from the BTS(130), and then reradiates it. In a shadow area(350), a remote repeater(152), a location information providing apparatus(200), and a wireless terminal(300) are located. The GPSOne server(132) stores satellite information on GPS satellites. The BTS(130) transmits and receives signals necessary for communication with the wireless terminal(300). The GPSOne server(132) receives GPS satellite signals, makes out a list of candidate GPSs, and provides this information to the wireless terminal(300). Based on the measurement information of the wireless terminal(300) and the information received from a GPS satellite, the GPSOne server(132) calculates the location of the wireless terminal(300). The location information providing apparatus(200) transmits a virtual GPS satellite signal to the wireless terminal(300). The wireless terminal(300), receiving the virtual GPS satellite signal, measures relative delay time and executes communication through the remote repeater(152).

Description

Apparatus and method for providing location information}

The present invention relates to an apparatus and method for providing location information, and more particularly, to location information for a wireless terminal located where a satellite signal transmitted from a GPS (Global Positioning System) satellite, such as a shielded space or an underground space, cannot be received. The present invention relates to a location information providing apparatus and a method for allowing a wireless terminal to measure a current location.

GPS is an all-weather positioning system that can measure the position of a stationary or moving object by receiving satellite signals transmitted from GPS satellites anywhere on Earth. GPS is a type of satellite-based radionavigation, which determines the spatial position by receiving a satellite signal transmitted from a GPS satellite that knows the exact location by tracked orbit and measuring the radio wave arrival time from the GPS satellite to the observation point. Therefore, the most important factor in determining the distance from the GPS satellite is time, and for this purpose, the GPS satellite is equipped with a very stable atomic clock. If the atomic clock on the GPS satellite and the clock on the GPS receiver are exactly the same, the distance between the three GPS satellites can determine the three-dimensional position. However, since the atomic clock mounted on the GPS satellites is very expensive, a relatively low-cost clock is used for the GPS receiver. To solve this problem, satellite signals and GPS receivers receive satellite signals from each of the four GPS satellites. It eliminates the unknown time difference that occurs in time.

The GPS currently in use is a global radio navigation satellite system developed and promoted by the US Department of Defense (DOD), and it is a system using NAVSTAR (NavSTAR System with Time And Ranging), a medium- and high-orbit navigation satellite system. Also known as GPS. The system consists of a total of 24 GPS satellites, each of which was launched on four circular orbits at an altitude of approximately 20,000 km, a period of about 12 hours, and an orbital inclination angle of 55 degrees. It is composed. In this system, four or more GPS satellites are arranged in the field of view at all times around the globe, so the user can select four of these GPS satellites and receive time signals from them to determine the distance of each. Measure At this time, the positions of the four selected GPS satellites can be known from the navigation signals contained in the GPS satellite signals, so that the user can know the three-dimensional position of the latitude, longitude, and altitude of the user and the visual deviation of the clock. do.

The transmission frequency from the GPS satellites is two waves of L1 (1,575.42 MHz) and L2 (1,227.6 MHz), and these two waves compensate for ionospheric delay. The satellite signal transmitted from the GPS satellites includes a 50bps navigation message, and is a phase shift modulated (PSK) signal spread spectrum modulated with a PRN code. There are two kinds of pseudo noise codes: P code (Cocision code) and C / A code (Coarse / Acquisition code) .These pseudo noise codes are used to decode navigation signal or measure distance between GPS satellite and receiving station. can do. L1 contains the P code and the C / A code, L2 contains only the P code. Currently, the C / A code has been released with a code pattern for private use, but the P code is secret. In addition, since the positioning accuracy by the C / A code is inferior to the accuracy by the P code, there is a limit in measuring the accurate position using only the C / A code available to the civilian.

Therefore, in order to increase the accuracy of the position measurement, a hybrid approach using a signal of the base station in addition to the GPS satellite signal is used. A typical hybrid approach is Qualcomm's GPSOne. Developed by Qualcomm's subsidiary SnapTrack, the GPSOne approach uses a hybrid approach that receives and utilizes both GPS satellite signals and pilot signals from CDMA base stations.

1 is a view for explaining the GPSOne method. Referring to the drawings, there are four GPS satellites 10, 12, 14 and 16 and a mobile communication terminal 20 having a GPSOne function. In addition, there is a CDMA network 40 including a BTS (Base Transceiver Station) 30, a GPSOne server 32, and a satellite antenna 34. The CDMA network 40 receives satellite signals from the GPS satellites 10, 12, 14, and 16 through the satellite antenna 34, and the GPSOne server 32 stores satellite information about the GPS satellites. The mobile communication terminal 20 receives satellite signals from the GPS satellites 10, 12, 14, and 16, calculates a relative range by measuring a relative delay time, and calculates a pseudorange, and the GPSOne server 32 of the CDMA network 40. Measure your current position through information exchange with.

However, in order to measure the current position of a wireless terminal such as a mobile phone using GPS, the wireless terminal basically needs to be in a state capable of receiving satellite signals transmitted from the GPS satellites. Therefore, it is impossible to measure the location using GPS in a wireless terminal that is located in a shielded space such as the inside of a building or in an underground space such as an underground shopping mall, a tunnel, an underground parking lot, and cannot receive satellite signals transmitted from a GPS satellite. There is a problem. In addition, while the development direction of the telecommunications market is toward wired / wireless integration, services such as LBS (Location Based Service), which is emerging as a major service in the mobile communication field, are also basically correct as the proportion of wireless communication is increasing. Since it is based on location tracking, it is necessary to remove small blocky shaded areas such as a shielded space or an underground space to enable location tracking using GPS anywhere.

The present invention has been made to solve the above problems, an object of the present invention is to provide location information to a wireless terminal located in a place that can not receive satellite signals transmitted from GPS satellites, such as a shielded space or underground space. Accordingly, an object of the present invention is to provide a location information providing apparatus and a method for accurately measuring a current location of a wireless terminal.

1 is a view for explaining a GPSone method;

2 is a view for explaining the operating environment of the location information providing apparatus according to the present invention;

3 is a schematic block diagram of a location information providing apparatus according to the present invention;

4 is a flowchart provided to explain an operation method for a location information providing apparatus according to the present invention;

5 is a view for explaining a process of generating a satellite signal;

6 is a view for explaining a process of position measurement, and

7 is a view showing an example of the configuration of the navigation message.

Explanation of symbols on the main parts of the drawings

140: CDMA network 150: master repeater

152: remote repeater 160: mobile communication device

200: location information providing device 210: location information storage unit

220: signal processor 230: modulator

240: timing module 300: wireless terminal

The location information providing apparatus according to the present invention for achieving the above object, provides a virtual GPS satellite signal to a wireless terminal having a GPS function, and based on the location information of the location where the wireless terminal is installed, the wireless terminal measures the current position And a signal processor for generating a satellite signal, and a modulator for generating the virtual GPS satellite signal modulated by the satellite signal and transmitting the virtual GPS satellite signal to the wireless terminal. Preferably, based on the pilot signal from the base station, generates predetermined clock and time information, and provides the generated predetermined clock and time information to the signal processor for use as a reference signal when generating the satellite signal. It further comprises a timing module unit, and a location information storage unit for storing the location information. In this case, the location information preferably includes latitude, longitude, altitude, and time information of the place where it is installed.

The satellite signal generated by the signal processor includes at least one of a pseudo noise code and a navigation message, and the pseudo noise code preferably uses a pseudo noise code that is not assigned to a GPS satellite.

The wireless terminal can calculate a location using a hybrid approach based on information from the base station for the virtual GPS satellite signal and the virtual GPS satellite signal. In this case, the information related to the virtual GPS satellite signal is preferably stored in the GPSOne server of the base station.

Preferably, the modulator generates the virtual GPS satellite signal by modulating the spread spectrum modulated phase shift signal using a predetermined carrier. In addition, the wireless terminal is preferably a mobile communication terminal having a GPSOne function.

On the other hand, the location information providing method according to the present invention, providing a virtual GPS satellite signal to a wireless terminal having a GPS function, (a) receiving the location information of the place of installation, (b) the input location information Generating a satellite signal enabling measurement of a current position of the wireless terminal based on the step (c) generating and transmitting the virtual GPS satellite signal modulated by the satellite signal to the wireless terminal; do. At this time, in the step (b), it is preferable to generate predetermined clock and time information on the basis of the pilot signal from the base station, and use the generated predetermined clock and time information when generating the satellite signal.

Preferably, (d) calculating a relative delay time for the virtual GPS satellite signal at the wireless terminal based on the virtual GPS satellite signal, and (e) from the calculated relative delay time and the base station. Computing the position of the wireless terminal based on the pilot signal information of the.

In the step (a), the location information includes latitude, longitude, altitude, and time information of the place where the installation, and in the step (b), the satellite signal includes a pseudo noise code and a navigation message desirable. In addition, the pseudo noise code, it is possible to use a pseudo noise code unallocated to the GPS satellites. In the step (c), it is preferable to generate the virtual GPS satellite signal by modulating the spread spectrum modulated phase shift using the predetermined carrier wave. The wireless terminal is preferably a mobile communication terminal having a GPSOne function.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

2 is a view for explaining the operating environment of the location information providing apparatus according to the present invention. Referring to the drawing, the CDMA network 140 includes a base transceiver station (BTS) 130, a GPSOne server 132, and a satellite antenna 134, and amplifies a signal transmitted from the BTS 130 to reconstruct it. There is a Master Repeater (150) to radiate. In the shaded area 350 such as a shielded space or an underground space, there is a remote repeater 152, a location information providing device 200, and a wireless terminal 300 such as a mobile phone.

In this configuration, a satellite signal is received from a GPS satellite (not shown) through the satellite antenna 134 of the CDMA network 140, the GPSOne server 132 stores satellite information about the GPS satellite, and the BTS 130 Transmits and receives signals required for communication with a mobile phone and the like. The GPSOne server 132 receives a GPS satellite signal, generates a candidate GPS satellite list including various parameters, and provides this information to the wireless terminal 300 as necessary, as well as the measurement information of the wireless terminal 300. The position of the wireless terminal 300 is calculated based on the received information from the GPS satellites. The master repeater 150 and the remote repeater 152 re-radiate the signal transmitted from the BTS 130 to the propagation shadow area 350. At this time, the remote repeater 152 is installed in the shaded area 350 to enable mobile communication and wireless call reception in the shaded area 350.

The location information providing apparatus 200 is installed in the shaded area 350 that is difficult to receive GPS satellite signals, and transmits a virtual GPS satellite signal to the wireless terminal 300 located in the shaded area 350. The wireless terminal 300 receives a virtual GPS satellite signal to measure a relative delay time, and at the same time communicates through the remote repeater 152. The mobile communication device 160 provides predetermined satellite information to the location information providing apparatus 200, which will be described later.

3 is a schematic block diagram of a location information providing apparatus 200 according to the present invention. Referring to the drawings, the location information providing apparatus 200 is composed of a location information storage unit 210, a signal processor 220, a modulator 230, and a timing module 240. The location information storage unit 200 receives and stores location information such as longitude, latitude, altitude, and time of the location where the location information providing device 200 is installed. The signal processor 220 generates a satellite signal that enables the wireless terminal 300 to measure the current position and generates a baseband signal with reference to the location information stored in the location information storage unit 210. At this time, the timing module 240 provides the signal processor 220 with the correct clock and time (1 PPS) to define at what point and start the transmission of the satellite signal at what speed. The clock provided by the timing module unit 240 is an integer multiple of 1.023 MHz, that is, a spreading frequency of the GPS signal, for example, 10.23 MHz, and the 1PPS (Pulse Per Second) signal takes a short pulse shape at every second boundary defined in the GPS signal. do. The timing module unit 240 generates the clock and time described above using the base station pilot signal received from the CMDA base station 140. That is, when the pilot signal is transmitted from the CMDA base station 140, since the transmission start time is aligned with the GPS even-second boundary, the GPS timing can be obtained indirectly by using this. In this case, the delay that occurs when the CDMA base station 140 is transmitted from the repeater to the repeater may generally be several microseconds to several tens of microseconds, but it is not unreasonable to use it as GPS timing.

The modulator 230 wirelessly modulates the generated satellite signal to generate a virtual GPS satellite signal, and transmits the generated GPS satellite signal to the wireless terminal 300.

4 is a flowchart provided to explain an operation method of the location information providing apparatus according to the present invention. Referring to the flowchart, the location information storage unit 210 of the location information providing apparatus 200 stores the location information of the location where the location information providing apparatus 200 is installed (S400). The signal processor 220 generates a satellite signal that allows the wireless terminal to measure the current location by referring to the location information stored in the location information storage unit 210 (S405). As shown in FIG. 5, the satellite signal generated by the signal processor 220 may use a pseudo random noise code, and may include a navigation message. Pseudo-noise codes look like noise, but are actually human-generated signals. P-codes or C / A codes are used. The C / A code repeats PRN (Pseudo Random Noise) having a bandwidth of 1.023 MHz, and the P code repeats a PRN having a bandwidth of 10.23 MHz. This pseudo-noise code is a unique code number of a satellite that is different for each GPS satellite, and is an index for identifying each GPS satellite. Therefore, the satellite signal generated by the signal processor 220 may be generated using an unassigned pseudonoise code not currently used in the GPS satellite, and information about this is pre-stored in the GPSOne server 132 to utilize a hybrid approach. One position measurement can be enabled.

The virtual GPS satellite signal generated by the signal processor 220 may also include a navigation message. 6 shows an example of a navigation message. As shown in Fig. 6, the frame of the navigation message is composed of five subframes. Subframe 1 includes the L2 code and data, the main number, a flag indicating the accuracy and status of the GPS satellites, the age of the data, and the satellite clock correction coefficient. Subframe 2 contains GPS satellite map information (Ephemeris Parameter), subframe 4 contains GPS satellites 25-32 orbit information, ionospheric model, UTC data, 32 satellite arrays, GPS satellites 25-32 status, etc. . Subframe 5 includes orbital information of GPS satellites 1 to 24 and states of GPS satellites 1 to 24. As described above, the signal processor 220 uses the clock and time provided by the timing module 240 when the baseband satellite signal is generated.

The modulator 230 modulates a satellite signal generated by the signal processor 200 into a spread spectrum modulated phase shift keying (PSK) signal using an L1 carrier to generate a virtual GPS satellite signal and generate the generated virtual satellite signal. The GPS satellite signal is transmitted to the wireless terminal 300. In some situations, the use of an L2 carrier may be considered.

The wireless terminal 300 receives a virtual GPS satellite signal from the location information providing apparatus 200 and calculates a pseudorange (S415). That is, as shown in FIG. 7, four virtual GPS satellite signals are received, a time difference Δt is calculated, and a pseudo distance is calculated by multiplying the calculated time differences by the speed c of light. Can be. Therefore, from the position of the wireless terminal 300, the pseudo distance is calculated using the virtual GPS satellite signal transmitted from the location information providing apparatus 200, and the pseudo distance is calculated using the satellite signal transmitted from the GPS satellite signal. There is no difference. The wireless terminal 300 exchanges information with the GPSOne server 132 of the base station 140 through the remote repeater 152 to calculate the position of the wireless terminal 300 through a hybrid approach (S420). At this time, the GPSOne server 132 of the base station 140 should already have information about the location information providing apparatus 200, it can be processed as a general GPS satellite using this information. In the same manner, a virtual GPS satellite signal is provided to a wireless terminal located in a shaded area where satellite signals from a GPS satellite cannot be directly received, and the wireless terminal receives a virtual GPS satellite signal to measure a current position. You can do it.

As described above, according to the present invention, the present invention provides a location information to a wireless terminal which is located in a shadow area, such as a building, an underground space, etc., to measure the current position of the wireless terminal by providing location information to a wireless terminal that cannot receive satellite signals from a GPS satellite. To help. When using such a location information providing device, the application of location tracking applications such as locating service, location information advertising, entertainment information services, games, children and the elderly safety services, asset tracking services in the building or underground space, etc. A variety of services can be provided.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (18)

In the location information providing apparatus for transmitting a virtual GPS satellite signal to a wireless terminal having a GPS function, A signal processor for generating a satellite signal based on the location information of the location where the wireless terminal can measure a current location; And And a modulator for generating the virtual GPS satellite signal modulating the satellite signal and transmitting the virtual GPS satellite signal to the wireless terminal. The method of claim 1, Generating predetermined clock and time information based on the pilot signal from the base station, and providing the generated predetermined clock and time information to the signal processor so as to be used as a reference signal when generating the satellite signal. And a timing module unit. The method of claim 1, Location information providing device further comprises; location information storage unit for storing the location information. The method of claim 3, The location information, latitude, longitude, altitude, and time information providing apparatus, characterized in that it comprises the time information. The method of claim 1, The satellite signal generated by the signal processor, at least any one of a pseudo noise code and a navigation message. The method of claim 5, The pseudo noise code is a location information providing device, characterized in that to use a pseudo noise code unallocated to the GPS satellites. The method according to any one of claims 1 to 3, And the wireless terminal calculates a location using a hybrid approach based on satellite information from the base station for the virtual GPS satellite signal and the virtual GPS satellite signal. The method of claim 7, wherein And the information related to the virtual GPS satellite signal is stored in a GPSOne server of the base station. The method of claim 1, And the modulator generates the virtual GPS satellite signal by modulating the spread spectrum modulated phase shift signal using a predetermined carrier. The method of claim 1, The wireless terminal is a location information providing device, characterized in that the mobile communication terminal having a GPSOne function. In the location information providing method for providing a virtual GPS satellite signal to a wireless terminal having a GPS function, (a) receiving location information of an installation place; (b) generating a satellite signal based on the inputted location information to measure a current location of the wireless terminal; And (c) generating the virtual GPS satellite signal modulated by the satellite signal and transmitting the virtual GPS satellite signal to the wireless terminal. The method of claim 11, In the step (b), based on the pilot signal from the base station, the predetermined clock and time information is generated, and the generated predetermined clock and time information is used for generating the satellite signal. How to Provide. The method according to claim 11 or 12, wherein (d) calculating a relative delay time for the virtual GPS satellite signal at the wireless terminal based on the virtual GPS satellite signal; And (e) calculating a position of the wireless terminal based on the calculated relative delay time and pilot signal information from the base station. The method of claim 11, In the step (a), wherein the location information includes the latitude, longitude, altitude, and time information of the place to be installed. The method of claim 11, wherein In the step (b), the satellite signal, location information providing method characterized in that it comprises at least one of a pseudo noise code and a navigation message. The method of claim 15, The pseudo-noise code, location information providing method characterized in that using a pseudo-noise code unallocated to the GPS satellites. The method of claim 11, In the step (c), the satellite GPS signal is generated by performing phase shift modulation of the satellite signal using a predetermined carrier to generate the virtual GPS satellite signal. The method of claim 11, The wireless terminal is a location information providing method, characterized in that the mobile communication terminal having a GPSOne function.