JP2003037867A - Radio terminal equipment and position determination system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide radio terminal equipment which measures a present position precisely even in a case that distinction of signals from base stations is difficult (an area or the like in which the same PN offset value is used repeatedly). SOLUTION: This radio terminal equipment is provided with a receiving means for receiving signals from a plurality of radio stations, a receiving timing analyzing means for analyzing receiving timing of the signal received by the receiving means, a radio station selecting means for selecting a radio station to be used for position calculation, and a position calculating means which calculates a position of a receiving point by using the receiving timing of the signal from the selected radio station. The radio station selecting means selects a radio station to be used for position calculation in such a manner that a signal from at least any one radio station is not used when receiving timings of signals from at least the two radio stations cannot be distinguished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless terminal device which measures a current position by using a wireless signal, and more particularly, which base station the signal is from when a plurality of base stations have the same PN offset value. The present invention relates to a wireless terminal device and a wireless positioning system that accurately measure a current position even when it is difficult to determine the.

[0002]

2. Description of the Related Art In mobile communication systems, there has been proposed a technique for detecting the position of a terminal using a signal transmitted from a base station. For example, Japanese Patent Laid-Open No. 7-181242 discloses a code division multiple access (CDMA).
tiple Access) system, the position of each base station,
There has been proposed a technique for measuring the position of a terminal by using a propagation delay time difference of a signal transmitted from each base station to the terminal.

For example, in the radio system shown in FIG. 11, the mobile terminal 800 has three cellular telephone base stations 80.
1. Receive signals from 1, 802 and 803. The mobile terminal 800 has a difference in propagation time of signals from the base stations 801, 802, and 803 (propagation time from the base station 801-base station 80.
2) and ((propagation time from base station 801−propagation time from base station 803)). The mobile terminal 800 calculates the current position of the mobile terminal 800 using the propagation time difference from each of the base stations 801 to 803.

[0004] Here, the TIA (Telecommunication In
dustry association) standard EIA / TIA-95
Consider the case of a compliant system. EIA / TIA-95
In the system, all base stations use the same spreading code (PN code) with a period of about 26.7 milliseconds. Also, each base station has a pilot PN offset (PN offset value) as a transmission time difference pre-assigned to each base station to identify the base station, and each base station shifts only the PN offset value from the reference timing. Sending a signal.

The mobile terminal obtains a reception profile by calculating the correlation value between the received signal and the PN code. For example, when the correlation value between the received signal and the PN code is calculated using the matched filter, the reception profile waveform as shown in FIG. 12 is obtained at the output of the matched filter.

In FIG. 12, 901, 902 and 903 are shown.
Are correlation values corresponding to the received signals from the base stations 801, 802 and 803, respectively. At this time, since each base station has a different PN offset value, the correlation value corresponding to the received signal from each base station can be obtained in a temporally separated state. Therefore, in the reception profile, it is possible to distinguish the received signal from each base station and the reception timing of the signal from each base station, so that the propagation time of the signal from each base station is used. The position can be measured.

[0007]

However, there are cases where base stations having the same PN offset value are close to each other in an area such as an urban area where base stations are densely packed. For example, when the same PN offset value is assigned to the base station 801 and the base station 802, the base station 801
As a matched filter output corresponding to 802 and 803, a reception profile waveform as shown in FIG. 13 is obtained.
That is, since the base stations 801 and 802 have the same PN offset value, the correlation value corresponding to the received signals from both base stations is substantially the same as 910, and the reception profile waveform (matched Filter output).

Thus, in the reception profile,
It is difficult to determine the reception timing by discriminating the reception signals that appear at the same time and overlapping each other for each base station. Therefore, it is highly possible that the correlation value 910 is erroneously determined from which base station. This erroneous determination gives a large error to the measurement of the propagation time of the signal from each base station, and causes the accuracy of the position measurement to deteriorate. If the accuracy of the position measurement deteriorates, the user cannot receive an appropriate position information service, and the convenience of the position information service deteriorates.

It is an object of the present invention to provide a wireless terminal device that accurately measures the current position even when it is difficult to distinguish the signals from the base station.

[0010]

In order to solve the above-mentioned problems, a wireless terminal device according to the present invention provides a receiving means for receiving signals from a plurality of wireless stations and a receiving timing of the signals received by the receiving means. Reception timing analyzing means for analyzing, radio station selecting means for selecting a radio station used for position calculation, and position calculating means for calculating the position of the reception point by using the reception timing of the signal from the selected radio station. And the radio station selecting means cannot distinguish the reception timing of signals from two or more radio stations (for example,
Since multiple wireless stations have the same PN offset value,
When reception profiles based on signals from two or more wireless stations overlap each other, a wireless station used for position calculation is selected so that signals from at least one wireless station are not used.

Further, the wireless terminal device according to the present invention includes receiving means for receiving signals from a plurality of wireless stations, receiving profile creating means for creating a receiving profile of the signals received by the receiving means, and the receiving profile. And information transmitting means for transmitting information for calculating the position of the receiving point using, the information transmitting means receives signals based on signals from two or more wireless stations among signals from the wireless stations. If the profiles cannot be distinguished (for example, a plurality of wireless stations have the same PN offset value), it is characterized by transmitting information used for eliminating a signal from at least one of the wireless stations. And

Further, the positioning system according to the present invention includes a plurality of wireless stations for transmitting signals to the wireless terminal device, a receiving means for receiving signals from the plurality of wireless stations, and the receiving means for receiving the signals. A wireless terminal device having a reception profile creation means for analyzing a reception profile of a signal, and position calculation means for calculating the position of a reception point using the reception profile, integrally with or separately from the wireless terminal device. When the signals from two or more wireless stations cannot be distinguished in the reception profile (for example, when a plurality of wireless stations have the same PN offset value), the position calculating means provides at least one of the wireless stations. The position is calculated by excluding the signal of.

Further, the position calculating device according to the present invention uses the wireless station selecting means for selecting the wireless station used for position calculation and the reception timing of the signals from the plurality of wireless stations received by the wireless terminal device. A position calculation unit that calculates the position of a reception point, and the wireless station selection unit cannot distinguish the reception timing of signals from two or more wireless stations (for example, a plurality of wireless stations have the same PN offset value). Therefore, when the reception profiles based on the signals from two or more wireless stations are overlapped, it is necessary to select the wireless station used for position calculation so that the signal from at least one wireless station is not used. Characterize.

[0014]

In the wireless terminal of the present invention, when the reception timings of signals from two or more wireless stations cannot be distinguished, position calculation is performed so that signals from at least one wireless station are not used. Since the wireless station selecting means for selecting the wireless station to be used is provided, it is possible to accurately calculate the current position of the mobile terminal even in an area where base stations having the same PN offset value are arranged in close proximity.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a wireless system (mobile communication system) in which a mobile terminal according to an embodiment of the present invention performs position measurement.

Cellular telephone base stations 101 to 105 as radio stations communicating with the mobile terminal 100 are provided around the mobile terminal 100 represented by a mobile phone. Different PN offset values PN1, PN3, and PN4 are assigned to the base stations 101, 103, and 104, respectively.
The same PN offset value PN2 is assigned to 02 and 105.

In the embodiment of the present invention, the mobile terminal 1
00 receives the signals transmitted from the base stations 101 to 105. The mobile terminal 100 measures the propagation distance difference from the propagation time difference of signals arriving from at least three base stations,
By the forward meeting method, the positions of the three base stations are known,
Measure the location of the wireless terminal.

FIG. 2 is a flowchart showing the position calculation operation of the mobile terminal according to the first embodiment of this invention.

First, the mobile terminal 100 selects a candidate base station used for position calculation (step 700). For example, the base stations 101 to 105 estimated to be in the vicinity are selected from the base station list stored in advance in the mobile terminal 100.

The mobile terminal 100 is connected to the base station 101.
To 105 generate a reception profile by calculating the correlation value between the reception signal transmitted by ˜105 and the PN code (step 701).
For example, when the correlation value between the received signal and the PN code is calculated using the matched filter, the reception profile waveform is obtained as the matched filter output. From this reception profile waveform, the earliest timing at which the correlation value becomes maximum is extracted as the reception timing, and the reception timing of the signal from each base station is measured (step 702).

Then, regarding base stations having the same PN offset value, a base station used for position calculation is selected so as to prevent the position measurement accuracy from being deteriorated by erroneously determining which base station the signal is from. (Step 703). Details of this selection method will be described later with reference to FIG.

Then, in step 703, the position of the mobile terminal 100 is calculated using the signal from the base station selected for use in position calculation (step 70).
4).

FIG. 3 is a flow chart showing details of the base station selection operation in step 703 in the position calculation operation described above with reference to FIG.

The mobile terminal 100 measuring the reception timing of the signal from each base station in step 702,
Of the candidate base stations used for position calculation selected in 00,
It is determined whether or not there is a base station having the same PN offset value (step 201). When there is no base station having the same PN offset value (“No” in step 201), the signals transmitted from the base stations are not received in the reception profile in an overlapping manner.
It is determined that all candidate base stations selected in step 700 will be used for position calculation (step 203).

On the other hand, when there is a base station having the same PN offset value (“Yes” in step 201),
Signals from base stations having the same PN offset value are received overlapping in the reception profile, and it is difficult to distinguish between them. Therefore, all base stations having the same PN offset value are not used for position calculation. The effect is determined (step 202).

As described above, in the first embodiment of the present invention, base stations having the same PN offset value are not used for position calculation at all. That is, in the wireless system shown in FIG. 1, both the base station 102 and the base station 105 are excluded from the position calculation. Therefore, even in an area where base stations having the same PN offset value are arranged close to each other, signals from the base stations having the same PN offset value are used for position calculation without being distinguished and the position of the mobile terminal is calculated. The deterioration of accuracy can be prevented.

In addition, even in such an area, it becomes possible to provide the user with accurate position information service,
The service area of the location information service is expanded, and the convenience of the location information service can be improved.

FIG. 4 is a flow chart showing details of the base station selection operation in the position calculation operation of the mobile terminal according to the second embodiment of the present invention.

In the second embodiment shown in FIG. 4, in FIG.
The first embodiment described above with reference to FIG. 3 and step 7
The base station selection operation in 03 (FIG. 2) is different, and other processing is the same as the operation shown in FIG.

The mobile terminal 100 measuring the reception timing of the signal from each base station in step 702 first calculates the temporary position of the mobile terminal 100 (step 300). For example, the position of the base station to which the mobile terminal 100 has transmitted the position registration signal for the wireless system is the temporary position of the mobile terminal 100. In addition, even if the candidate base stations selected in step 700 (FIG. 2) except the base station having the same PN offset value are used as the temporary position, the result of position calculation using another base station may be used. Good.

Then, among the candidate base stations selected in step 700 (FIG. 2), the base station having the same PN offset value is selected. In the wireless system shown in FIG. 1, the base station 102 having the same PN offset value PN2.
And the base station 105 are selected (step 301).

Then, the distance between the base stations 102 and 105 having the same PN offset value selected in step 301 and the temporary position of the mobile terminal is calculated for each base station (step 302). That is, the mobile terminal 100
The distance 122 between the temporary position of the mobile terminal 100 and the base station 102 and the distance 125 between the temporary position of the mobile terminal 100 and the base station 105 are calculated.

Then, the difference in distance with each base station calculated in step 302 is calculated (step 303). That is, the difference between the distance 122 and the distance 125 is calculated.

Then, the difference in distance between the base station having the same PN offset value and the provisional position of the mobile terminal is compared with a predetermined value (threshold value) which has been set in advance (step 304). Then, based on the comparison result, it is determined whether the base station having the same PN offset value as the comparison target is added to the position calculation.

That is, the difference between the distance 125, which is the distance between the base stations 102 and 105 having the same PN offset value, and the provisional position of the mobile terminal 100, and the distance 125 is compared with a predetermined threshold value (step). 304). Then, when the difference between the distance 122 and the distance 125 is equal to or larger than a predetermined threshold value,
Since the distance to the base station 102 and the distance to the base station 105 are not close to each other and the propagation delay times of the signals from both base stations are different, the signals from both base stations can be distinguished from each other. Of the base stations that have a PN offset value,
Select the base station closest to the temporary position of the mobile terminal 100,
It is determined that this base station should be added to the position calculation (step 306).

Specifically, in addition to the base stations 101, 103 and 104 having different PN offset values, the same P
Of the base stations 102 and 105 having the N offset value PN2, it is determined that the base station 105 closest to the temporary position of the mobile terminal is used for position calculation. Then, the reception timing of the signals that appear overlapping in the reception profile is
This reception timing is used for position calculation as that of the base station closest to the temporary position.

On the other hand, when the difference between the distance 122 and the distance 125 is less than the predetermined threshold value, the distance to the base station 102 and the distance to the base station 105 are close, and the propagation delay times are almost equal. Since it is difficult to distinguish the signals from the stations, it is determined that base stations with the same PN offset value are excluded from the position calculation (step 30).
5). Specifically, the base stations 102 and 105 having the same PN offset value PN2 are not used in the position calculation, and the base stations 101 and 1 having different PN offset values are used.
It is decided to use only 03 and 104 for position calculation.

As described above, in the second embodiment of the present invention, among base stations having the same PN offset value, the base station estimated to be close to the mobile terminal is selected and used for position calculation. To do. That is, in the wireless system shown in FIG. 1, the base station 10 existing nearer to the base station 102 is
Signals from 5 are used for position calculation, and signals from distant base stations 102 are excluded from position calculation. Therefore, it is possible to calculate the position of the mobile terminal with high accuracy even in an area where base stations having the same PN offset value are arranged close to each other, and even in such an area, the user can obtain accurate position information. The service can be provided, the service area of the location information service is expanded, and the convenience of the location information service can be improved.

When the difference in the distance to the base stations having the same PN offset value is small, it is difficult to distinguish which base station the signal is from, and therefore the base stations having the same PN offset value. The position of the mobile terminal can be obtained more accurately because the position of the mobile terminal is calculated by excluding all of the above.

FIG. 5 is a flow chart showing details of the base station selection operation in the position calculation operation of the mobile terminal according to the third embodiment of the present invention.

In the third embodiment shown in FIG. 5, in FIG.
The first embodiment described above with reference to FIG. 3 and step 7
The base station selection operation in 03 (FIG. 2) is different, and other processing is the same as the operation shown in FIG.

The mobile terminal 100 measuring the reception timing of the signal from each base station in step 702 first calculates the temporary position of the mobile terminal 100 (step 400). For example, as described above in step 300 (FIG. 4), the calculation of the temporary position may be performed by using the position of the base station to which the mobile terminal 100 has transmitted the position registration signal for the wireless system as the temporary position of the mobile terminal 100, or step 700. Among the candidate base stations selected in (FIG. 2), the base station having the same PN offset value is excluded, and the position calculation result is used as the temporary position using other base stations.

Then, among the candidate base stations selected in step 700 (FIG. 2), the base station having the same PN offset value is selected. In the wireless system shown in FIG. 1, the base station 102 having the same PN offset value PN2.
And the base station 105 are selected (step 401).

Then, the estimated value of the timing at which the signal from each base station selected in step 401 is received by the mobile terminal is calculated (step 402). The estimated value of the reception timing is the mobile terminal 100 calculated in step 400.
It is calculated from the distance between the provisional position and the base stations 102 and 105. That is, the propagation time is calculated by dividing the distance from each base station by the propagation velocity (light velocity) of the radio wave, and the estimated value of the reception timing is calculated.

Then, the reception timing measurement value of the reception signal from the base station having the same PN offset value that appears in the reception profile overlapping in time measured in step 702 (FIG. 2) and calculated in step 402. The calculated difference from the received timing estimated value for the base station having the same PN offset value is calculated as an error in the received timing (step 403).

Then, regarding the error between the reception timing estimation value and the reception timing measurement value calculated for each of the base stations having the same PN offset value, the same PN
The difference between the errors is calculated between the base stations having the offset value (step 404). That is, the difference between the reception timing error for the base station 102 and the reception timing error for the base station 105 is calculated.

Then, the difference in reception timing error calculated for each of the base stations having the same PN offset value is compared with a predetermined value (threshold value) which has been determined in advance (step 405). Then, based on the comparison result, it is determined whether the base station having the same PN offset value as the comparison target is added to the position calculation.

That is, the difference between the reception timing error for the base station 102 having the same PN offset value and the reception timing error for the base station 105 is compared with a predetermined threshold value (step 405). . When the difference between the reception timing error for the base station 102 and the reception timing error for the base station 105 is greater than or equal to a predetermined threshold, the distance to the base station 102 and the distance to the base station 105 are not close to each other. Since the signals from both base stations have different propagation delay times, it is possible to distinguish the signals from both base stations. Therefore, among the base stations having the same PN offset value, the one with the smallest reception timing error It is determined to select a station and add this base station to the position calculation (step 406). Here, the base station that gives the minimum value of the reception timing error is selected and used for position calculation, because the signals received with this overlap are the bases that give the minimum value of the reception timing error that arrives earliest. This is because it is likely that the signal is from the station.

Specifically, in addition to the base stations 101, 103 and 104 having different PN offset values, the same P
Among the base stations 102 and 105 having the N offset value PN2, it is determined that the base station 105 having the smallest error between the reception timing estimation value and the reception timing measurement value is used for position calculation. Then, regarding the reception timings of the signals that appear overlapping in the reception profile, the reception timing is used for the position calculation, assuming that the reception timing is that of the base station with the smallest reception timing error.

On the other hand, if the difference between the reception timing error for the base station 102 and the reception timing error for the base station 105 is less than a predetermined threshold value, it is difficult to distinguish the signals from both base stations. , It is determined that base stations having the same PN offset value are excluded from the position calculation (step 407). Specifically, the same PN
The base stations 102 and 105 having the offset value PN2 are
Neither is used in position calculation, and it is determined that only base stations 101, 103 and 104 that do not have different PN offset values are used in position calculation.

FIG. 6 is a diagram showing the relationship of the reception timing when the third embodiment (FIG. 5) is applied to the radio system shown in FIG. In this figure, step 7
The reception timing measurement value calculated in 02 (FIG. 1) and the reception timing estimation value calculated in step 402 (FIG. 5) are shown.

In the radio system shown in FIG. 1, the base station 10
2 and the base station 105 are assigned the same PN offset value. Since the signals from the base station 102 and the base station 105 have the same PN offset value, the reception timing measurement value 410 can be obtained at the timings overlapping with each other by the reception profile analysis using the matched filter ( Step 702).

The temporary position of the mobile terminal 100 and the base station 1
From the position of 02, the distance between the two is calculated, and the propagation delay time is calculated by dividing this distance by the speed of light.
The estimated value of the reception timing of 2 is obtained. Similarly, the estimated value of the reception timing is also obtained for the base station 105 having the same PN offset value as the base station 102 (step 4).
02). The reception timing estimated values are represented by 411 and 412 in FIG. 6, respectively.

Then, the difference between each reception timing measurement value measured in step 702 and each reception timing estimation value calculated in step 402 is calculated as an error in reception timing (step 403). The error of this reception timing is shown by 414 and 413 in FIG.

Then, with respect to the base stations 102 and 105 having the same PN offset value, the difference in the reception timing error, that is, the difference between the errors 413 and 414 in the example of FIG. 6 is calculated (step 404).

Then, the error difference (error 414-error 413) calculated in step 404 is compared with a preset threshold value, and among the base stations having the same PN offset value, the reception timing error is It is decided whether to add the smallest base station to the position calculation.

As described above, in the third embodiment of the present invention, it is estimated that among the base stations having the same PN offset value, the reception timing error is small and is close to the actual reception timing measurement value. Select a base station to use for position calculation. That is, in the wireless system shown in FIG. 1, the base station 10 that minimizes the error in the reception timing.
The signal from 5 is used for the position calculation, and the signal from the base station 102 having a large reception timing error is excluded from the position calculation. Therefore, it is possible to calculate the position of the mobile terminal with high accuracy even in an area where base stations having the same PN offset value are arranged close to each other, and even in such an area, the user can obtain accurate position information. The service can be provided, the service area of the location information service is expanded, and the convenience of the location information service can be improved.

Further, when the difference between the reception timing errors of the base stations having the same PN offset value is small, it is difficult to distinguish which base station the signal is from.
Since the base station having the same PN offset value is excluded and the position of the mobile terminal is calculated, the position of the mobile terminal can be obtained more accurately.

FIG. 7 is a flow chart showing the position calculating operation of the mobile terminal according to the fourth embodiment of the present invention.

In the fourth embodiment shown in FIG. 7, in FIG.
The method of selecting a base station used for position calculation (steps 710 to 714) is different from that of the first embodiment described above in FIG. 3, and other processing (steps 700 to 702) is the same as the operation shown in FIG. is there.

First, the mobile terminal 100 selects a candidate base station used for position calculation (step 700). For example, the base stations 101 to 105 estimated to be in the vicinity are selected from the base station list stored in advance in the mobile terminal 100.

The mobile terminal 100 is connected to the base station 101.
The correlation values between the received signals from ˜105 and the PN code are calculated to create a reception profile (step 701). For example, when the correlation value between the received signal and the PN code is calculated using the matched filter, the reception profile waveform is obtained as the matched filter output. From this reception profile waveform, the earliest timing at which the correlation value becomes maximum is extracted as the reception timing, and the reception timing of the signal from each base station is measured (step 702).

Then, the base station combination Cj (j = 1 ... M) is determined from the candidate base stations used for position calculation selected in step 700 by using a part of the base stations (step 710). This base station combination is determined so that one base station having the same PN offset value is included, that is, a plurality of base stations having the same PN offset value are not included in one base station combination. To do. Specifically, in the radio system shown in FIG. 1, the first base station combination is composed of base stations 101, 102, 103 and 104, and the second base station combination is base stations 101, 103,
It is composed of 104 and 105. Thus, in step 710, the base station 10 having the same PN offset value
Only one of 2 and 105 is included in the same base station combination,
The base station combination is determined so that both base stations 102 and 105 having the same PN offset value are not included in the same base station combination.

Then, the position of each reception point is calculated using each base station combination Cj (j = 1 ... M) determined in step 710, and the position calculation result (Xj, Yj) is calculated (step 711).

Then, for each position calculation result (Xj, Yj) calculated in step 711, the error function value F
Calculate the position measurement error using (j). This positioning error can be calculated using the following equation, for example.

[0067]

[Equation 1]

In the mathematical expression 1, the first term on the right side in {} is the distance between the mobile terminal and the base station 0 calculated from the coordinates on the map, and the second term on the right side in {}. Represents the distance between the mobile terminal and the base station i. Therefore, in {},
It represents the difference between the distance from the reference base station 0 and the distance from the i-th base station i. The third term on the right side represents the difference between the distance between the mobile terminal and the reference base station 0, which is obtained from the reception timing measurement result, and the distance between the mobile terminal and the base station i. By correctly measuring the reception timing,
Since the difference between the two distances approaches 0, it can be determined that the smaller the value of F (j), the more accurate the mobile terminal position is required.

Then, the error function value F (j) corresponding to each base station combination Cj calculated in step 712.
, JMIN that minimizes the value of (step 71
3), position calculation result corresponding to jMIN (XjMIN, YjMI
N) is selected and the position calculation result is determined as the position of the mobile terminal. As is clear from the above, “N” in the above formula
Is N = (the number of base stations belonging to Cj) -1.

The fourth embodiment will be specifically described by applying it to the radio system shown in FIG. Base stations 101, 1
The base station combination of 02, 103 and 104 and the base station 10
The terminal position is calculated using each of the base station combinations of 1, 103, 104 and 105 (step 711), and the positioning error is calculated using the error function value F (j) (step 712). Then, the terminal position calculated using the base station combination having the smaller calculated error function value is used as the position calculation result (steps 713 and 714).

As described above, in the fourth embodiment of the present invention, a plurality of sets of base stations including one base station having the same PN offset value are created and the position accuracy of the mobile terminal is calculated. Then, the set of base stations having the smallest position accuracy is selected, that is, the base station having the same PN offset value that gives the minimum position accuracy is selected, and the position of the mobile terminal is calculated. Even in an area where base stations having the same PN offset value are arranged close to each other, the position of the mobile terminal can be calculated with high accuracy.

FIG. 8 is a diagram showing a configuration related to position calculation in the mobile communication system in which the mobile terminal according to the embodiment of the present invention calculates position.

The mobile terminal 2 selects a base station 1 suitable for a communication partner from a plurality of base stations and communicates with the selected base station 1 via the wireless line 5. Further, the mobile terminal 2 receives a signal from a base station other than the base station 1 currently setting the wireless line 5 for handover or the like. Then, the position of the mobile terminal 2 is measured by the signals received from the plurality of base stations.

The base station 1 is connected to the public network 3 and
It mediates communication between the mobile terminal 2 and another communication device (not shown) connected to the mobile terminal 2. The base station 1 also communicates with the position information server 4 connected to the public network 3 to send and receive information necessary for position calculation.

FIG. 9 is a block diagram showing the configuration of the mobile terminal 2.

The signal from the base station 1 received by the antenna 10 is sent to the signal receiving section 11. Signal receiver 11
Is composed of a radio unit (reception unit, transmission unit), a baseband processing unit, and the like. In the radio unit, high-frequency signal and intermediate-frequency signal amplification and frequency conversion reception processing are performed, and in the baseband processing unit, base processing is performed. Demodulation processing of the band signal is performed.

The signal processed by the signal receiving unit 11 is input to the reception profile creating unit 12. The reception profile creation unit 12 is configured by using, for example, a matched filter, calculates a correlation value between the reception signal and the PN code for each reception timing, and indicates a value corresponding to the correlation value at each reception timing. Create a profile.

The reception profile created by the reception profile creation unit 12 is stored and held in the reception profile holding unit 13. The CPU 14 stores the storage device 15 (for example,
According to the software stored in the memory), the processing required for position calculation is performed using the reception profile held in the reception profile holding unit 13.

The mobile terminal 2 can be configured so that the reception profile creation unit 12 and the reception profile holding unit 13 are connected to the CPU 14 as one semiconductor device (LSI). Further, the reception profile creation unit 12, the reception profile holding unit 13, and the CPU 14
Alternatively, one LSI may be configured to be connected to the storage device 15. Further, the reception profile creation unit 12, the reception profile holding unit 13, the CPU 14, and the storage device 15 may constitute one LSI.

FIG. 10 shows an example of the configuration of the position information server 4. The CPU 20 executes data communication and data processing with the public network 3 according to the software stored in the storage device 21. Specifically, the position information server 4 stores information about the base station (for example, the position of the base station, the PN offset of the base station, etc.), and stores the information in the mobile terminal 2 based on the request from the mobile terminal 2. Send. Also, the position of the mobile terminal 2 is calculated using the reception profile based on the signal from the base station received by the mobile terminal 2.

Next, how the mobile terminal 2 realizes the position calculation processing shown in FIG. 2 will be described.

First, the CPU 14 of the mobile terminal 2 selects a candidate base station used for position calculation (step 70).
0). Then, the signal receiving unit 11 receives the signal from the candidate base station, and the reception profile creating unit 12 creates the reception profile by calculating the correlation value between the reception signal and the PN code (step 701). Holding part 13
Keep in memory.

Thereafter, the CPU 14 extracts the reception timing of the signal from the candidate base station from the reception profile stored in the reception profile holding unit 13 and measures the reception timing of the signal from the base station (step 70).
2). Then, it is determined whether the signal from the base station having the same PN offset value is used for position calculation, the base station used for position calculation is selected (step 703), and the position of the mobile terminal 2 is calculated (step 703). Step 704).

The position of the mobile terminal 2 thus calculated may be used by the CPU 14 (mobile terminal 2), or after the position information server 4 is notified via the base station 1 and the public network 3. It may be configured to be used.

Next, an example in which the mobile terminal 2 and the position information server 4 share and execute the position calculation process shown in FIG. 2 will be described.

First, the CPU 14 of the mobile terminal 2 selects a candidate base station used for position calculation (step 70).
0). Then, the signal receiving unit 11 receives the signal from the candidate base station, and the reception profile creating unit 12 creates the reception profile by calculating the correlation value between the reception signal and the PN code (step 701). Holding part 13
Keep in memory.

Thereafter, the CPU 14 extracts the reception timing of the signal from the candidate base station from the reception profile stored in the reception profile holding unit 13 and measures the reception timing of the signal from the base station (step 70).
2). Then, the CPU 14 notifies the position information server 4 of the reception timing of the signal from each base station obtained in step 702 via the base station 1 and the communication network 3.

The CPU 20 of the position information server uses the reception timing of the signal from each of the base stations to identify the same PN.
It is determined whether the signal from the base station having the offset value is used for position calculation, the base station used for position calculation is selected (step 703), and the position of the mobile terminal 2 is calculated (step 704). The position of the mobile terminal 2 calculated in step 704 may be used by the CPU 20 (position information server 4) or may be used after being notified to the mobile terminal 2 via the public network 3 and the base station 1. May be.

As described above, all the steps of the position calculation process are not performed by the mobile terminal 2, but a part of the position calculation process is performed by the position information server 4 connected to the base station 1, which is complicated. Since such processing is performed by the position information server 4 having a large calculation processing capacity, the position of the mobile terminal 2 can be calculated at high speed without imposing a processing load on the mobile terminal 2.

Next, how the mobile terminal 2 realizes the position calculation operation shown in FIG. 7 will be described.

First, the CPU 14 of the mobile terminal 2 selects a candidate base station used for position calculation (step 70).
0). Then, the signal receiving unit 11 receives the signal from the candidate base station, and the reception profile creating unit 12 creates the reception profile by calculating the correlation value between the reception signal and the PN code (step 701). Holding part 13
Keep in memory.

Thereafter, the CPU 14 extracts the reception timing of the signal from the candidate base station from the reception profile stored in the reception profile holding unit 13 and measures the reception timing of the signal from the base station (step 70).
2). Then, the CPU 14 performs processing from determining the combination of base stations to calculating the terminal position (steps 710 to 714).
To execute. The position of the mobile terminal 2 calculated in step 714 may be used by the CPU 14 (mobile terminal 2) or may be used after being notified to the position information server 4 via the base station 1 and the public network 3. It may be configured as follows.

Next, an example in which the mobile terminal 2 and the location information server 4 share and execute the location calculation processing shown in FIG. 7 will be described.

First, the CPU 14 of the mobile terminal 2 selects a candidate base station used for position calculation (step 70).
0). Then, the signal receiving unit 11 receives the signal from the candidate base station, and the reception profile creating unit 12 creates the reception profile by calculating the correlation value between the reception signal and the PN code (step 701). Holding part 13
Keep in memory.

Thereafter, the CPU 14 extracts the reception timing of the signal from the candidate base station from the reception profile stored in the reception profile holding unit 13 and measures the reception timing of the signal from the base station (step 70).
2). Then, the CPU 14 notifies the position information server 4 of the reception timing of the signal from each base station obtained in step 702 via the base station 1 and the communication network 3.

The CPU 20 of the position information server uses the reception timings of the signals from the respective base stations to perform the processing from the determination of the combination of base stations to the calculation of the terminal position (step 7).
10 to 714) are executed. The position of the mobile terminal 2 calculated in step 714 may be used by the CPU 14 (mobile terminal 2), or via the base station 1 and the public network 3,
The location information server 4 may be configured to be used after being notified.

As described above, all the steps of the position calculation process are not performed by the mobile terminal 2, but a part of the position calculation process is performed by the position information server 4 connected to the base station 1, which is complicated. Since such processing is performed by the position information server 4 having a large calculation processing capacity, the position of the mobile terminal 2 can be calculated at high speed without imposing a processing load on the mobile terminal 2.

The following are typical examples of the aspects of the present invention other than those described in the claims.

A plurality of wireless stations for transmitting signals to the wireless terminal device, a receiving means for receiving signals from the plurality of wireless stations, and a reception profile creation for analyzing the reception profile of the signals received by the receiving means. And a wireless terminal device having means for calculating the position of the reception point using the reception profile, the position calculating means being provided integrally with or separately from the wireless terminal device.
When the above signals from the wireless stations cannot be distinguished in the reception profile (for example, the wireless stations have the same PN).
(When the signals from two or more wireless stations cannot be distinguished in the reception profile because of the offset value)
In the positioning system for eliminating the signal from at least one of the wireless stations to calculate the position, the position calculating means uses a wireless station used for position calculation among the wireless stations that cannot distinguish the reception timing, A positioning system for calculating a position without using a signal from a wireless station other than a wireless station having a minimum distance between the temporary position and the wireless station for position calculation.

[0100] A plurality of wireless stations for transmitting signals to the wireless terminal device, a receiving means for receiving signals from the plurality of wireless stations, and a reception profile creation for analyzing the reception profile of the signals received by the receiving means. And a wireless terminal device having means for calculating the position of the reception point using the reception profile, the position calculating means being provided integrally with or separately from the wireless terminal device.
When the above signals from the wireless stations cannot be distinguished in the reception profile (for example, the wireless stations have the same PN).
(When the signals from two or more wireless stations cannot be distinguished in the reception profile because of the offset value)
In a positioning system that excludes signals from at least one of the wireless stations to perform position calculation, and further includes reception timing error estimation means for estimating an error in reception timing of signals from the wireless stations, The position calculation means is
Among the wireless stations whose reception timings cannot be distinguished, a wireless station used for position calculation is defined as an error in the reception timing of the signal (for example, as an error in the reception timing, the reception timing error estimation means determines the signal from the wireless station). Radio positioning for performing position calculation without using signals from radio stations other than the radio station having the smallest propagation time and the propagation time obtained from the position of the radio station and the provisional position of the reception point for position calculation system.

Radio station selecting means for selecting a radio station to be used for position calculation, and position calculating means for calculating the position of the receiving point by using the reception timings of the signals from the plurality of radio stations received by the wireless terminal device. And the wireless station selection means,
When the reception timings of signals from two or more wireless stations cannot be distinguished (for example, because the wireless stations have the same PN offset value, reception profiles based on signals from the two or more wireless stations overlap, A position calculating device that selects a wireless station to be used for position calculation so that the signal from at least one of the wireless stations is not used when the reception timing of the signal from the wireless station cannot be distinguished. The selecting means uses a wireless station used for position calculation among wireless stations whose reception timings cannot be distinguished, and a signal from a wireless station other than a wireless station having the shortest distance between the temporary position and the wireless station for position calculation. A position calculation device that selects not to perform.

Wireless station selecting means for selecting a wireless station to be used for position calculation, and position calculating means for calculating the position of the reception point by using the reception timings of signals received by the wireless terminal device from a plurality of wireless stations. And the wireless station selection means,
When the reception timings of signals from two or more wireless stations cannot be distinguished (for example, because the wireless stations have the same PN offset value, reception profiles based on signals from the two or more wireless stations overlap, A position calculating device that selects a wireless station to be used for position calculation so that the signal from at least one of the wireless stations is not used when the reception timing of the signal from the wireless station cannot be distinguished. The selecting means selects a radio station used for position calculation among the radio stations whose reception timings cannot be distinguished from each other, as an error in the reception timing of the signal (for example, the reception timing error estimating means as an error in the reception timing,
A signal from a wireless station other than a wireless station having a minimum propagation time of the signal from the wireless station and the propagation time obtained from the position of the wireless station and the provisional position of the reception point is not used for position calculation. Positioning device to select.

A program for causing a wireless terminal device to execute a position calculating method for receiving signals from a plurality of wireless stations and calculating the position of a receiving point by using the reception timing of the received signals, The wireless terminal device includes means for analyzing the reception timing of the received signal, means for selecting a wireless station to be used for position calculation, and a reception point using the reception timing of the signal from the selected wireless station. When it is not possible to distinguish the reception timing of the signals from the two or more wireless stations from the means for calculating the position (for example, since the wireless stations have the same PN offset value, the signals from the two or more wireless stations are If the reception profiles of signals from wireless stations cannot be distinguished from each other due to overlapping of the reception profiles based on, the signal from at least one of the wireless stations should not be used. Program to function as a means for selecting a radio station used for position calculation.

A semiconductor device used in a wireless terminal device, comprising a receiving unit for receiving signals from a plurality of wireless stations, and calculating the position of a receiving point using the received signals, the receiving unit receiving the signal. Reception timing analysis means for analyzing the reception timing of the signal, radio station selection means for selecting the radio station used for position calculation, and reception timing of the reception point using the reception timing of the signal from the selected radio station. Position calculating means for calculating a position, and the wireless station selecting means cannot distinguish reception timings of signals from two or more wireless stations (for example, since the wireless stations have the same PN offset value). , When the reception profiles based on the signals from the two or more radio stations overlap and the reception timings of the signals from the radio stations cannot be distinguished), at least one of the radios So that it does not use the signal from,
A semiconductor device, wherein a wireless station used for position calculation is selected.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a wireless system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a position calculation operation of the mobile terminal according to the first embodiment.

FIG. 3 is a diagram illustrating a position calculation operation according to the first embodiment,
It is a flowchart which shows the detail of operation | movement of a base station selection.

FIG. 4 is a diagram illustrating a position calculation operation according to the second embodiment,
It is a flowchart which shows the detail of operation | movement of a base station selection.

FIG. 5 shows a position calculation operation according to the third embodiment,
It is a flowchart which shows the detail of operation | movement of a base station selection.

FIG. 6 is a timing chart showing a relationship of reception timing in the third embodiment.

FIG. 7 is a flowchart showing a position calculation operation of the mobile terminal according to the fourth embodiment.

FIG. 8 is a configuration diagram of a mobile communication system according to the embodiment of the present invention.

FIG. 9 is a block diagram of a mobile terminal according to the embodiment of the present invention.

FIG. 10 is a block diagram of a position information server according to the embodiment of this invention.

FIG. 11 is a configuration diagram of a conventional wireless system.

FIG. 12 is a diagram showing a reception profile in a conventional wireless system.

FIG. 13 is a diagram showing another reception profile in the conventional wireless system.

[Explanation of symbols]

1 Base Station 2 Mobile Terminal 3 Public Network 4 Position Information Server 100 Mobile Terminals 101, 102, 103 Cellular Telephone Base Stations 122, 125 Distance between Mobile Terminal and Cellular Telephone Base Station 800 Mobile Terminals 801, 802, 803 Cellular Telephone Base Stations 811, 812, 813 Distance between mobile terminal and cellular telephone base station

Continued front page    (72) Inventor Mikio Kuwahara             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. (72) Inventor Koji Watanabe             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. F-term (reference) 5K022 EE01 EE33 EE36                 5K047 AA12 BB01 GG34 HH15 JJ06                       MM11                 5K067 AA21 BB02 BB21 BB36 CC10                       CC24 DD20 DD41 DD51 EE02                       EE10 FF03 JJ52

Claims (20)

[Claims] 1. A receiving means for receiving signals from a plurality of wireless stations, a receiving timing analyzing means for analyzing a receiving timing of signals received by the receiving means, and a wireless station for selecting a wireless station used for position calculation. Selection means and position calculation means for calculating the position of the reception point using the reception timing of the signal from the selected wireless station, wherein the wireless station selection means is a signal from two or more wireless stations. A wireless terminal device for selecting a wireless station to be used for position calculation so that a signal from at least one wireless station is not used when the reception timings of the wireless terminals cannot be distinguished. 2. The wireless station selecting means, since a plurality of wireless stations among the wireless stations have the same PN offset value, reception profiles based on signals from the two or more wireless stations are overlapped, The radio station used for position calculation is selected so that the signal from at least one of the radio stations is not used for position calculation when the reception timing of the signal from the radio station cannot be distinguished.
The wireless terminal device according to. 3. The wireless station selection means selects a wireless station used for position calculation so that signals from wireless stations whose reception timings cannot be distinguished are not used at all. The wireless terminal device according to. 4. A provisional position calculating means for calculating a provisional position of the reception point, wherein the radio station selecting means selects a radio station used for position calculation among the radio stations whose reception timings cannot be distinguished from each other. The wireless terminal device according to claim 1, wherein a signal from a wireless station other than a wireless station having a shortest distance from the wireless station is selected not to be used for position calculation. 5. A reception timing error estimating means for estimating an error in reception timing of a signal from the radio station, wherein the radio station selecting means is used for position calculation among radio stations whose reception timing cannot be distinguished. The wireless terminal device according to claim 1 or 2, wherein a station is selected so that a signal from a wireless station other than a wireless station having a minimum reception timing error of the signal is not used for position calculation. 6. A provisional position calculation means for calculating a provisional position of the reception point, wherein the reception timing error estimation means comprises a signal propagation time from the radio station, a position of the radio station and a provisional reception point. The wireless terminal device according to claim 5, wherein a difference between the position and the propagation time obtained from the position is obtained as an error in the reception timing. 7. Receiving means for receiving signals from a plurality of wireless stations including a plurality of wireless stations having the same PN offset, and reception timing analyzing means for analyzing the reception timing of the signals received by the receiving means. Position calculating means for calculating the position of the reception point using reception timings of signals from a plurality of wireless stations, wherein the position calculating means is composed of a plurality of wireless stations each having a different PN offset value. The position of the reception point is calculated using the signal from the radio station belonging to the first set of radio stations, and the radio station and the reception point belonging to the set of the first radio station calculated using the calculation result From the information about the distance between the wireless station belonging to the first set of wireless stations and the receiving point calculated using the reception timing analysis result, the error of the position of the receiving point, So The position of the reception point is calculated using the signals from the wireless stations belonging to the second wireless station group, each of which is composed of a plurality of wireless stations having different PN offset values, and the calculation result is used to calculate the position. Between the wireless station belonging to the second set of wireless stations and the receiving point, and information about the distance between the wireless station belonging to the second set of wireless stations and the receiving point. From the information on the distance, the error of the position of the receiving point is obtained, and the calculation result of the position of the receiving point obtained by using the set of the wireless stations with the smaller error is taken as the position of the receiving point. Wireless terminal device. 8. A wireless terminal device for calculating the position of a reception point using signals from a plurality of wireless stations, the receiver receiving signals from the wireless stations, and the signals received by the receivers. When the reception timing analysis circuit that analyzes the reception timing of the above and the reception timing of the signals from the two or more wireless stations cannot be distinguished, it is used for position calculation so that the signal from at least one of the wireless stations is not used. A wireless terminal device, comprising: a controller that selects a wireless station and calculates the position of a reception point using the reception timing of a signal from the selected wireless station. 9. Receiving means for receiving signals from a plurality of wireless stations, receiving profile creating means for creating a receiving profile of signals received by the receiving means, and position of a receiving point using the receiving profile. An information transmitting unit for transmitting information for calculating, wherein the information transmitting unit is a signal from the wireless station,
A wireless terminal device, which transmits information used for eliminating a signal from at least one of the wireless stations when the reception profile based on the signal from the wireless station cannot be distinguished. 10. The information transmitting means, at least when signals from the two or more wireless stations cannot be distinguished in a reception profile because a plurality of wireless stations among the wireless stations have the same PN offset value. The wireless terminal device according to claim 9, wherein the wireless terminal device transmits information used to exclude a signal from any wireless station from position calculation. 11. The information transmitting means transmits information used for selecting a wireless station used for position calculation so that signals from wireless stations which cannot be distinguished in the reception profile are not used at all. The wireless terminal device according to claim 9 or 10. 12. Receiving signals from a plurality of wireless stations,
A wireless terminal device for calculating the position of a reception point, comprising: a receiver for receiving a signal from the wireless station; a reception profile creation unit for creating a reception profile of a signal received by the receiver; If the signals from the wireless stations are indistinguishable in the reception profile, the information used to select the wireless station used for the position calculation is excluded so that the signals from at least one of the wireless stations are excluded from the position calculation. A wireless terminal device comprising: a control device that functions to generate. 13. A plurality of wireless stations that transmit signals to a wireless terminal device, a receiving unit that receives signals from the plurality of wireless stations, and a receiving unit that analyzes a reception profile of the signals received by the receiving unit. A wireless terminal device having a profile creating means, the position calculating means for calculating the position of the reception point using the reception profile, provided integrally or separately with the wireless terminal device, the position calculating means, A positioning system, characterized in that when signals from two or more wireless stations cannot be distinguished in a reception profile, signals from at least one of the wireless stations are excluded to perform position calculation. 14. The position calculating means, at least when signals from two or more wireless stations cannot be distinguished in a reception profile because a plurality of wireless stations among the wireless stations have the same PN offset value. The positioning system according to claim 13, wherein the position calculation is performed by excluding a signal from any one of the wireless stations. 15. The position calculating means calculates the position without using any signal from a wireless station that cannot be distinguished in the reception profile.
Or the positioning system according to 14. 16. Reception means for receiving signals from a plurality of radio stations including a plurality of radio stations having the same PN offset, and reception timing analysis means for analyzing reception timing of signals received by the reception means. Position calculating means for calculating the position of the reception point using reception timings of signals from a plurality of wireless stations, wherein the position calculating means is composed of a plurality of wireless stations each having a different PN offset value. The position of the reception point is calculated using the signal from the radio station belonging to the first set of radio stations, and the radio station and the reception point belonging to the set of the first radio station calculated using the calculation result From the information on the distance between the wireless station belonging to the first set of wireless stations and the receiving point calculated using the reception timing analysis result, the error of the position of the receiving point, The position of the reception point is calculated using the signals from the wireless stations belonging to the second wireless station set, each of which is composed of a plurality of wireless stations having different PN offset values, and the calculated result is used. Between the calculated distance between the wireless station belonging to the second wireless station set and the reception point, and the wireless station belonging to the second wireless station set calculated using the reception timing analysis result and the reception point From the information on the distance of the position of the receiving point, the error of the position of the receiving point is obtained, and the calculation result of the position of the receiving point obtained by using the set of wireless stations having the smaller error is set as the position of the receiving point. Positioning system. 17. A radio station selecting means for selecting a radio station used for position calculation, and a reception timing of a signal from a radio station selected by the radio station selecting means from a plurality of radio stations received by a radio terminal device. Position calculating means for calculating the position of the receiving point using the wireless station selecting means, wherein the wireless station selecting means determines from at least one of the wireless stations when the reception timings of the signals from the two or more wireless stations cannot be distinguished. A position calculating device which selects a wireless station to be used for position calculation so that the above signal is not used. 18. The wireless station selection means, since a plurality of wireless stations among the wireless stations have the same PN offset value, the reception profiles based on signals from the two or more wireless stations are overlapped, and When the reception timing of the signal from the station cannot be distinguished, the wireless station used for position calculation is
The position calculation device according to claim 17, wherein a signal from at least one of the wireless stations is selected not to be used for position calculation. 19. The wireless station selection means selects a wireless station to be used for position calculation so as not to use a signal from a wireless station whose reception timing cannot be distinguished at all. The position calculation device described in 1. 20. A position of a reception point is calculated using reception timings of signals received from a plurality of wireless stations including a plurality of wireless stations having the same PN offset, and a plurality of positions each having a different PN offset value are calculated. Radios belonging to the first set of radio stations calculated using the result of calculation by calculating the position of the reception point using signals from the radio stations belonging to the first set of radio stations From the information about the distance between the station and the receiving point and the information about the distance between the wireless station belonging to the first set of wireless stations and the receiving point calculated using the reception timing analysis result, the position of the receiving point The error of is calculated, the position of the reception point is calculated using the signals from the wireless stations belonging to the second wireless station group composed of a plurality of wireless stations each having a different PN offset value, and the calculation result Calculated using Information on the distance between the wireless station belonging to the second wireless station group and the receiving point, and the distance between the wireless station belonging to the second wireless station group and the receiving point calculated using the reception timing analysis result An error is calculated from the information and the position of the receiving point, and a position calculating means is provided which sets the calculation result of the position of the receiving point, which is obtained by using the set of wireless stations having the smaller error, as the position of the receiving point. A position calculation device characterized by the above.