Background technology
Always, following localization method is disclosed: built-in GPS receiver in portable terminal, use signal separately, or use from the signal of gps satellite with from the signal of cellular basestation and confirm terminal location (for example, with reference to patent documentation 1) from gps satellite.At the outdoor environment that does not have barrier, portable terminal can receive the signal from gps satellite fully, can receive the signal from gps satellite more than 4 in most of place.
In the location of having used GPS, because therefore three-dimensional location coordinates X, Y, Z and be unknown in the time of reception at terminal need the signal of reception from least 4 gps satellites.That is,, then can only confirm the position with GPS if can receive signal from the gps satellite more than 4.
In addition, because portable terminal is used for various places, for example in the corridor, building or the indoor portable terminal that also uses.In such environment, portable terminal can not be caught the faintness wave (signal) from gps satellite, many times can only receive signal from the gps satellite of 4 of less thaies.If can only receive signal, then can not only measure the position of portable terminal like this through gps satellite from the gps satellite of 4 of less thaies.
As the countermeasure of this situation, following mixing (hybrid) locate mode is disclosed, even can only receive the position that signal also can be measured portable terminal from the gps satellite of 4 of less thaies.Through the mixed positioning mode, this method is not only to carry out position calculation with GPS, but cellular basestation is handled as one of signal transmission source.
Particularly, the reception through measuring the signal that sends from cellular basestation is regularly handled cellular basestation with gps satellite thus comparably, makes signal number be not less than 4.Therefore, thus can measure the position of portable terminal in various places.In addition, as special circumstances,,, then also can measure the position of portable terminal through same method if can receive the signal that sends from the base station more than 4 even under the situation of the signal that does not have to receive from gps satellite.
In said method, the signal source quantity that requires receivable GPS and cellular basestation is more than 4.The receivable signal source quantity of portable terminal is because of the situation around the portable terminal is different, signal number also arranged less than 4 situation.
As the countermeasure of this situation, disclose sub-district (cell)/sector (sector) locate mode.Particularly, the position calculation with the cellular basestation at portable terminal place is the position of portable terminal.If cellular basestation by sectorization, then can use the center of this sector.In addition, in the time can measuring RTT (Round Trip Time), can calculate the distance between cellular basestation~portable terminal, therefore also can measure the position of portable terminal with this distance and sector auxiliary information.Having used the mobile terminal locating method of cell/section locate mode to be used as can't be with the compensation process in the place of GPS location or mixed positioning.If the service area of portable terminal (service area) then is the method that can measure the position of portable terminal.
As stated, the locate mode of portable terminal has multiple mode, has disclosed the method (for example, with reference to non-patent literature 1) of switching GPS location, mixed positioning or cell/section location according to the environment for use of portable terminal.
In non-patent literature 1, judge the switching of locate mode according to receivable signal source.Particularly,, signal source quantity selects GPS location or mixed positioning if being more than 4, if 4 of less thaies then select the cell/section location.
[patent documentation 1] spy opens the 2005-20216 communique
[Patent Document 1] "precision positioning pts zip Shin ョ ni nn bag cis Te Rousseau Full Applied と thermal - Bldg su expand" Shin pts zip ウ Rousseau Te キ su Suites p.43-54 as of March 3 Promotion of Machine Industry Hall 2 underground bands ホ - Hikaru Main reminder: Corp.? Electronics Information and Communication Engineers? Tokyo Branch
Summary of the invention
The positioning accuracy of cell/section location is than GPS location or mixed positioning low precision.Therefore, selected cell/section to locate in the receivable signal source quantity of portable terminal less than 4 o'clock.
Yet; When portable terminal is positioned at the corridor, building or when indoor etc.; The signal degradation that portable terminal receives when receiving from the signal of cellular basestation even receivable sometimes signal number is more than 4, can not obtain sufficient positioning accuracy through GPS location or mixed positioning.
On the other hand, the portable terminal quantity that is positioned at sub-district (sector) is more, be that cell density is high more, and then the positioning accuracy of cell/section location is just high more.Just, there is proportionate relationship between radius of society and the positioning accuracy.Therefore, in the little city of radius of society, in the corridor, building or indoor etc. when using mixed positioning, compare with the cell/section location, positioning accuracy is poorer sometimes.
Therefore; The present invention is in view of above problem and proposing, and its purpose is to be provided at server unit, portable terminal and the location mode selection method of the locate mode that suitably Select Error is little from available locate mode under the independent situation that can't measure mobile terminal locations with GPS.
In order to achieve the above object; First characteristic of the present invention is; A kind of server unit, it estimates that to the position that receives the portable terminal that communicates from the signal of gps satellite and with the base station this server unit has: (a) locating information parsing portion; It selects to use a certain locate mode in cell/section location or the mixed positioning according to the distance between base station and the portable terminal; (b) position detection part, it uses the locate mode of being selected by locating information parsing portion, calculates the position of portable terminal.
According to the server unit of first characteristic, can be under the situation that can't implement to locate with GPS separately from available locate mode, the locate mode that Select Error is little.
In addition, in the server unit of first characteristic, also can confirm distance according to the two-way time between said base station and the said portable terminal.
In addition; The locating information parsing portion of the server unit of first characteristic also can calculate the threshold value of regulation according to the evaluated error of the evaluated error of cell/section location and mixed positioning; The threshold value and the distance of this regulation are compared; Under the distance situation littler, select the cell/section location than defined threshold.
Second characteristic of the present invention is; A kind of portable terminal; It receives the signal from gps satellite, and communicates with the base station, and this portable terminal has: (a) locating information parsing portion; It selects to use a certain locate mode in cell/section location or the mixed positioning according to the distance between base station and the portable terminal; (b) position detection part, it uses the locate mode of being selected by locating information parsing portion, calculates the position of portable terminal.
The 3rd characteristic of the present invention is; A kind of location mode selection method; It selects the locate mode used when the position that receives the portable terminal that communicates from the signal of gps satellite and with the base station estimated; This location mode selection method comprises the steps: (a) according to the distance between base station and the portable terminal, selects to use a certain locate mode in cell/section location or the mixed positioning; (b) use selected locate mode, calculate the position of portable terminal.
According to the present invention, can provide can be under the situation that can't measure separately mobile terminal locations with GPS server unit, portable terminal and the location mode selection method of the locate mode that suitably Select Error is little from available locate mode.
Embodiment
Below, with reference to accompanying drawing execution mode of the present invention is described.In the record of following accompanying drawing, for the identical or similar label of identical or similar part mark.Wherein, it should be noted that accompanying drawing is a sketch map.
(structure of communication system)
The communication system of this execution mode possesses: portable terminal 100, and its reception communicates from the signal of gps satellite and with cellular basestation 200; Cellular basestation 200; And calculation server 300, its position to portable terminal 100 is estimated.
Portable terminal 100 receives the signal from gps satellite, and communicates with cellular basestation 200.Portable terminal 100 possesses GPS acceptance division 101, cellular communication portion 102 and data store 103.
GPS acceptance division 101 comprises gps antenna, RF portion, dependent part and the signal processing part of reception from the signal of gps satellite.GPS acceptance division 101 uses the information of the gps satellite signal sequence that in the signal that gps antenna receives, contains, and confirms to receive the intrinsic number (below be called " satellite ID ") of satellite.
GPS acceptance division 101 is for each receivable gps satellite, and the reception of signal calculated regularly and the time of reception.Afterwards, GPS acceptance division 101 sends to data store 103 and comprises the gps satellite number that can receive signal, satellite ID, reception timing and the gps satellite information of the time of reception of this satellite.
Cellular communication portion 102 is through receiving the pilot signal that cellular basestation 200 sends, the cellular basestation that decision communicates and its sector.Here, the sector with the cellular basestation that is determined is called the sector, place.Cellular communication portion 102 sends the base station information of the sector, place of the intrinsic number that comprises the base station (below be called " base station IDs ") and this base station IDs to data store 103.
In addition, cellular communication portion 102 uses wireless communication line, sends to calculation server 300 via cellular basestation 200 and is kept at gps satellite information and the base station information in the data store 103.
The gps satellite information that data store 103 storages are sent from GPS acceptance division 101.In addition, data store 103 is stored the base station information that sends from cellular communication portion 102.
Cellular basestation 200 communicates with portable terminal 100.In addition, cellular basestation 200 receives gps satellite information and base station information from portable terminal 100.Cellular basestation 200 sends to calculation server 300 through network and sends gps satellite information and the base station information that receives.
Two-way time (RTT) between cellular basestation 200 mensuration base station~portable terminals.Cellular basestation 200 when receiving the request signal of RTT mensuration, sends the request signal of measuring beginning to portable terminal 100 from calculation server 300.Cellular basestation 200 is regularly measured RTT through measuring to send regularly with receiving.Through the mensuration result of network to calculation server 300 transmission RTT.
The needed information of position finding (calculating) that calculation server 300 is collected portable terminal 100, the position of calculating portable terminal 100.Portable terminal 100 sends to portable terminal 100 with result of calculation.Calculation server 300 has server communication portion 301, locating information parsing portion 302 and position detection part 303.
Server communication portion 301 receives gps satellite information and base station information through cellular basestation 200 from portable terminal 100.Server communication portion 301 sends to locating information parsing portion 302 with gps satellite information that receives and base station information.In addition, server communication portion 301 receives the RTT information that cellular basestation 200 is measured from cellular basestation 200.Server communication portion 301 sends to locating information parsing portion 302 with the RTT information that receives.
Then, server communication portion 301 is from the position calculation result of position detection part 303 mobile terminal receives 100.Server communication portion 301 sends to portable terminal 100 through cellular basestation 200 with the position calculation result who receives.
Locating information parsing portion 302 measures the result according to gps satellite information, base station information and RTT and selects preferred orientation.In this execution mode, use GPS location, three kinds of modes of mixed positioning and cell/section location.
302 pairs of location positioning errors based on these three kinds of locate modes of locating information parsing portion are estimated.In order to carry out this estimation, use the gps satellite number and base station number, the reception timing of signal and configuration, place sector auxiliary information and the RTT of satellite and base station that can be used for position calculation to measure the result.About the system of selection of this method of estimation and locate mode, will narrate in the back.
Position detection part 303 uses the locate mode of selecting in locating information parsing portion 302 to carry out the position calculation of portable terminal 100, and the position calculation result is sent to server communication portion 301.
(location mode selection method)
Below, use Fig. 2 that the system of selection of the locate mode of this execution mode is described.
At first, the locating information parsing portion 302 indicating positions test sections 303 of calculation server 300 are attempted utilizing GPS to locate (S201) separately.Then, position detection part 303 utilizes portable terminal 100 can receive gps satellite number signal, that be may observe and position error is judged, judgement could be carried out GPS and locate (S202) separately.
At step S202, can carry out GPS when locating separately, locating information parsing portion 302 selects the GPS location as locate mode.Position detection part 303 uses the GPS location to carry out the position calculation of portable terminal 100, end process (S208).
On the other hand, at step S202, can not carry out GPS when locating separately, position detection part 303 entrusts RTT to measure through server communication portion 301 to cellular basestation 200.Cellular basestation 200 is measured RTT (S203).
Then, locating information parsing portion 302 200 receives base station informations (base station IDs, sector number) and RTT measures result (S204) from the base station.Then, locating information parsing portion 302 is according to base station IDs, sector number, according to after the method stated obtain cell/section and locate effective threshold X (S205).The relation of obtaining RTT and position error (cell/section location and mixed positioning) through prior enforcement simulation decides threshold X.
302 couples of RTT that measured of locating information parsing portion and threshold X compare (S206).In step S206, under the RTT situation littler than X, the cell/section location is selected by locating information parsing portion 302.Position detection part 303 uses the cell/section location to carry out the position calculation of portable terminal 100, and end process (S209).
On the other hand, in step S206, be X when above at RTT, utilize observable satellite number, observable base station number and position error to judge, judge and could carry out mixed positioning (S207).In step S207, in the time can carrying out mixed positioning, mixed positioning is selected by locating information parsing portion 302.Position detection part 303 uses mixed positioning to carry out the position calculation of portable terminal 100, and end process (S210).
On the other hand, in the time in step S207, can not carrying out mixed positioning, the cell/section location is selected by locating information parsing portion 302.Position detection part 303 uses the cell/section location to carry out the position calculation of portable terminal 100, end process (S210).
Below, an example of the computational methods of the threshold X among the description of step S205.In the calculating of threshold X, calculate the evaluated error of cell/section location and the evaluated error of mixed positioning, obtain the intersection point of these range performance curves.
At first, the computational methods of the position estimation error E_sector of cell/section location are narrated.As shown in Figure 3, in cell/section location, obtain portable terminal 100 places the sector position of centre of gravity and with it as positioning result.Then, obtain have a few and the distance of the position of centre of gravity of sector in the sector.Because this distance is the evaluated error at each point.With just drawing the average evaluated error E_sector in the sector divided by the sector area after the evaluated error addition of each point.
On the other hand, calculate the evaluated error of mixed positioning as follows.In mixed positioning; Utilize the distance between the cellular basestation~portable terminal that calculates according to the distance between the gps satellite~portable terminal of calculating with according to the RTT between cellular basestation~portable terminal, carry out 3 limits and measure from the reception timing ga(u)ge of the signal of gps satellite.
Here, consider the mixed positioning of having utilized the RTT between 2 gps satellites and 1 cellular basestation~portable terminal.If the range error of establishing between gps satellite~portable terminal is σ _ GPS1, σ _ GPS2, the range error of establishing between cellular basestation~portable terminal is σ _ BS, then can use the position estimation error E_Hybrid in formula (1) the expression mixed positioning.
E_Hybrid={ (σ _ GPS1)
2+ (σ _ GPS2)
2+ (σ _ BS)
21/2 ... Formula (1)
About σ _ GPS1, σ _ GPS2, σ _ BS, can be through repeatedly measuring to use its RMS (RootMean Square: root mean square).In addition, also can use the value that obtains through experience to estimate σ _ GPS1, σ _ GPS2, σ _ BS.
Fig. 4 representes an example of the analog result of position estimation error E_sector and the position estimation error E_Hybrid in the mixed positioning in the cell/section location.As shown in Figure 4, can know that E_sector and E_Hybrid have intersection point.The threshold X of this moment is just used the value of this intersection point.
In addition; In the system of selection of above-mentioned locate mode; As cell/section location, the situation of using the sector ID locate mode has been described, in this sector ID locate mode, obtain the portable terminal place the sector position of centre of gravity and with this position of centre of gravity as positioning result; And, also can use other modes as the cell/section location.
For example, Fig. 5 has represented to use the situation of sub-district ID locate mode.In the ID locate mode of sub-district, calculate the centre coordinate of sub-district according to latitude, longitude, sub-district, the place ID of base station.That is, the coordinate with the base station carries out estimation approach as the position of portable terminal.
In addition, Fig. 6 has represented to use the situation of RTT locate mode.In the RTT locate mode, be that the intersection point with circle that calculates according to RTT and sector center line carries out estimation approach as the position of portable terminal.
In addition; In the step S209 of Fig. 2; When having selected the location, sector; Also can from above-mentioned sector ID locate mode, sub-district ID locate mode, RTT locate mode, select to use any locate mode in detail according to observable gps satellite number, the base station number that can measure RTT or sub-district kind.As the sub-district kind, for example can enumerate is sector cell or whole sub-district.
(change example)
Then, use Fig. 7 that the change example of the communication system of this execution mode is described.As shown in Figure 7, in the communication system of change example, portable terminal 400 is collected the required information of selection of locate mode.That is, portable terminal 400 is selected preferred orientation according to the mensuration result of observable gps satellite number, observable base station number and RTT, carries out the position calculation of portable terminal 400.
The communication system of change example has cellular basestation 200, portable terminal 400 and information server 500.
Cellular basestation 200 communicates with portable terminal 400.In addition, the two-way time (RTT) between cellular basestation 200 mensuration cellular basestations 200~portable terminal 400.Cellular basestation 200 sends the request signal of measuring beginning to portable terminal 400 when receiving the request signal of RTT mensuration.Cellular basestation 200 regularly regularly carries out RTT mensuration with receiving through measuring transmission.
In addition, cellular basestation 200 is through the mensuration result of wireless communication line to portable terminal 400 transmission RTT.
Portable terminal 400 receives the signal from gps satellite, and communicates with cellular basestation 200, carries out position calculation.
GPS acceptance division 401 comprises gps antenna, RF portion, dependent part and the signal processing part of reception from the signal of satellite.GPS acceptance division 401 is employed in the information of the gps satellite signal sequence that comprises in the signal that gps antenna receives, and confirms to receive the satellite ID of satellite, and the reception of calculating receivable each satellite regularly and the time of reception.Afterwards, GPS acceptance division 101 sends to position detection part 404 and comprises the gps satellite number that can receive signal, satellite ID, reception timing and the gps satellite information of the time of reception of this gps satellite.
Cellular communication portion 402 is through receiving the pilot signal that cellular basestation 200 is sent, decide the cellular basestation and its sector that communicates.In addition, cellular communication portion 402 sends the base station information of the sector, place that comprises base station IDs and this base station IDs to locating information parsing portion 403.
In addition, cellular communication portion 402 receives RTT from cellular basestation 200 and measures the result.Cellular communication portion 402 sends the RTT that receives from cellular basestation 200 to locating information parsing portion 403 and measures the result.
Locating information parsing portion 403 measures the result according to gps satellite information, base station information and RTT and selects preferred orientation.As locate mode, adopt GPS location, mixed positioning, location, sector as stated.
302 pairs in locating information parsing portion utilizes the location positioning error of these three kinds of locate modes to estimate.In order to carry out this estimation, the reception of adopting the gps satellite number that can be used for position calculation and base station number, signal is regularly measured the result with configuration, place sector auxiliary information and the RTT of satellite and base station.About location mode selection method, with illustrated in fig. 2 the same.
Selected locate mode is carried out the position calculation of portable terminal 400 in the position detection part 404 use locating information parsing portions 403.
Therefore the location mode selection method of change example omits its explanation here owing to the same with flow chart shown in Figure 2.
(effect and effect)
According to system of selection based on the locate mode of the calculation server 300 of this execution mode, portable terminal 100; Can be according to the distance between cellular basestation 200 and the portable terminal 100; Select to use a certain locate mode in cell/section location or the mixed positioning, and use selected locate mode to calculate the position of portable terminal 100.
Therefore, can be under the situation that separately can't implement to locate with GPS from available locate mode the little locate mode of Select Error.
In addition, also can directly use RTT to replace the distance between cellular basestation 200 and the portable terminal 100.
In addition, in this execution mode, calculate the threshold value of regulation according to the evaluated error of the evaluated error of cell/section location and mixed positioning.And, the threshold value of this regulation and the distance between cellular basestation~portable terminal are compared, under this distance situation littler, select the cell/section location than defined threshold.
Thought the cell/section locating accuracy than mixed positioning difference in the past, but in the less city of cell size etc., the good situation of cell/section locating accuracy was arranged also.In this execution mode, also can select the little locate mode of position error in this case.
In addition, when selecting locate mode,, can also select locate mode according to the sub-district kind of base station except distance.For example, through selecting locate mode, can select more to meet actual preferred orientation according to sector cell or whole sub-district.