JP2007163297A - Positioning terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the time and the cost of communication incurred for displaying positioning result in a positioning terminal, and to enable a single terminal to be used even for different positioning methods. <P>SOLUTION: The positioning terminal 1 is equipped with an autonomous positioning section 11, a wireless positioning section 12, a dead navigation section 13, a position-compensating section 14, a positioning arithmetic section 15, a position information displaying section 16 and a positioning software memory section 18. The autonomous positioning section 11 outputs inertial data, according to the walking action of a person holding the positioning terminal 1, and the dead navigation section 13 infers the position information based on the inertial data. Meanwhile, the wireless positioning section 12 and the positioning arithmetic section 15 which are operated by a positioning software that has been loaded from the positioning software memory section 18 and run by a CPU, receive/demodulate wireless signal and carry out positioning operation, according to the frequency, modulation method and positioning method of the wireless signal. The position-compensating section 14 compensates the positional information, by using the positions input from the dead navigation section 13 and the positioning arithmetic section 15. Then, the position information displaying section 16 displays the positional information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a portable information terminal having a positioning function.

Recent portable information terminals are equipped with various sensors and GPS (Global Positioning Systems) receivers, and multifunctional and high performance including a positioning function are being accelerated. In addition, position-related infrastructures such as next-generation satellite positioning systems (modernized GPS, Galileo satellite, Quasi-Zenith Satellite (QZS)), RFID (Radio Frequency Identification) tags, and sensor nets are being developed. In Japan, it has been decided that all third-generation mobile phones will be equipped with location detection functions after April 2007 (Ministry of Internal Affairs and Communications, June 2004), and will provide location-related services in the future. Is expected to become more active, and easy-to-use services are expected. Note that Patent Literature 1 discloses a network assist compatible GPS position detection system capable of selecting and setting an arbitrary positioning mode from a plurality of GPS positioning modes.
JP 2002-196063 A

However, conventional portable information terminals (hereinafter referred to as positioning terminals) having a positioning function have the following problems.
(1) It takes time to display the positioning result and communication cost.
(2) Since the positioning method and the modulation method differ depending on the satellite positioning system and indoors and outdoors, it is necessary to install individual hardware in order to support each method.
(3) Every time a new positioning signal appears, the manufacturer needs to develop hardware corresponding to the signal.

  Therefore, in view of the above problems, the present invention provides means for reducing the time and communication cost for displaying positioning results in a positioning terminal, and enabling positioning with a single terminal even with different positioning methods. This is the issue.

  The present invention that solves the above-described problems is a radio positioning unit that receives a positioning radio signal, demodulates the received radio signal, and outputs the demodulated positioning data, and inputs positioning data from the radio positioning unit, A positioning terminal including a positioning calculation unit that performs positioning calculation according to input positioning data and outputs position information as a result of the positioning calculation, and a position information display unit that inputs position information from the positioning calculation unit and displays the position information. And a software storage unit for storing first software corresponding to the frequency and modulation scheme of the radio signal and second software corresponding to the positioning scheme related to the positioning data, wherein the CPU has the first software Is loaded into a predetermined memory from the software storage unit and executed in accordance with the frequency and modulation method of the radio signal. 2 software, loaded from the software storage unit in a predetermined memory, and executes in response to a positioning method according to the positioning data. The present invention includes other positioning terminals (such as positioning terminals that perform autonomous positioning).

  ADVANTAGE OF THE INVENTION According to this invention, the time and communication cost concerning the display of a positioning result can be reduced in a positioning terminal. Further, even with different positioning methods, positioning can be performed with a single terminal.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

≪Software radio positioning≫
First, software radio positioning, which is a feature in the embodiment of the present invention, will be described. In conventional wireless positioning, separate hardware is required for each frequency, modulation method, and signal structure. For example, in the configuration of a positioning terminal, an ASIC (Application Specific Integrated Circuit) or an ASIC is provided between a radio frequency signal receiving unit and a positioning calculation unit in order to support L1C / A signals, L2C signals, Galileo signals, RFID signals, and the like. Individual dedicated hardware such as DSP (Digital Signal Processor) was required.

  Therefore, in the embodiment of the present invention, signal acquisition processing and signal tracking processing, which has been performed by conventional dedicated hardware, are programmed and processed at high speed by a CPU (Central Processing Unit), so that various frequencies, modulation schemes, Be compatible with signal structures. As for satellite positioning systems and terrestrial wireless positioning, new positioning methods are expected to appear one after another. In that case, the necessary software, such as a program that implements new satellite signal processing and an accuracy improvement algorithm, is downloaded to the wireless receiver, and the CPU executes the software so that it can be executed with a single hardware (wireless receiver). Even if it exists, a plurality of positioning functions can be realized. Such a radio receiver is called a software radio receiver.

≪Positioning terminal configuration and overview≫
FIG. 1 is a diagram showing a configuration of a positioning terminal and its surroundings according to an embodiment of the present invention. Here, the positioning terminal 1 has a configuration in which the portable information terminal is specialized for the positioning function. Actually, the positioning terminal 1 may be realized as a positioning terminal alone or as a function of the portable information terminal together with other functions. May be. The positioning terminal 1 is assumed to be carried and used by a pedestrian rather than being mounted on a vehicle or the like. Because it is not intended for navigation along the roadway, positioning time, accuracy, power consumption, etc. can be selected according to the purpose and preference of the user, and it can be used regardless of the indoor or outdoor positioning method. This is because high-precision, high-efficiency multifunctional positioning is realized with this terminal.

  As shown in FIG. 1, the positioning terminal 1 includes an autonomous positioning unit 11, a radio positioning unit 12, a dead reckoning navigation unit 13, a position correction unit 14, a positioning calculation unit 15, a position information display unit 16, a satellite orbit storage unit 17, and a positioning. A software storage unit (software storage unit) 18 is included.

  The autonomous positioning unit 11 includes an acceleration sensor 111, an angular velocity sensor 112, and a magnetic direction sensor 113. Each of these sensors outputs the data measured by itself to the dead reckoning navigation unit 13. Details will be described later.

  The radio positioning unit 12 includes a radio frequency signal processing unit 121 and a software signal processing unit 122. The radio frequency signal processing unit 121 receives an external radio frequency signal (positioning radio signal), A / D (Analog / Digital) converts the received signal, and converts the data after the A / D conversion into software. Output to the signal processing unit 122. The software signal processing unit 122 inputs data from the radio frequency signal processing unit 121, and performs acquisition and synchronization processing on the input data by a modulation method according to a signal such as L1C, L2C, and L5. The demodulated data (positioning data) is output to the positioning calculation unit 15. Specifically, the radio frequency signal processing unit 121 and the software signal processing unit 122 are realized by the CPU executing positioning software (first software) corresponding to the frequency and modulation method related to the received radio frequency signal. Is done. For the positioning software, the latest code is loaded from the positioning software storage unit 18 into a predetermined memory when the positioning terminal 1 is turned on or necessary.

  The dead reckoning unit 13 estimates the position by dead reckoning using data input from the autonomous positioning unit 11 and the positioning calculation unit 15 (particularly, the satellite positioning processing unit 151), and sends the position data to the position correction unit 14. Output. The estimated position data may be directly output to the position information display unit 16. Details of dead reckoning will be described later. The position correction unit 14 corrects the position based on the data input from the dead reckoning navigation unit 13 and the positioning calculation unit 15, and outputs the position data to the position information display unit 16. Details of the position correction will be described later. In addition, dead reckoning part 13 and position correction | amendment part 14 are implement | achieved when CPU runs the program stored in the predetermined memory.

  The positioning calculation unit 15 has a function of performing a positioning calculation according to a positioning method, and includes a satellite positioning processing unit 151, an RFID positioning processing unit 152, and a wireless LAN positioning processing unit 153. Each positioning processing unit is activated according to a positioning method related to data (positioning data) input from the wireless positioning unit 12, performs positioning calculation, accuracy calculation, and the like, and outputs the results to the position correction unit 14. The calculated position data may be directly output to the position information display unit 16. Each positioning processing unit is realized by the positioning software (second software) corresponding to the positioning method related to the data being executed by the CPU. For the positioning software, the latest code is loaded from the positioning software storage unit 18 into a predetermined memory when the positioning terminal 1 is turned on or necessary. Moreover, the positioning calculation part 15 is provided with the function which inputs the positioning conditions set by the owner of the positioning terminal 1 as a previous step of positioning calculation, and specifies the positioning method suitable for the positioning conditions.

  The satellite positioning processing unit 151 receives a data from a positioning satellite such as a GPS satellite and performs a positioning calculation. The satellite positioning processing unit 151 performs satellite positioning every predetermined time (for example, 2 hours), obtains the satellite general orbit and the precise orbit of each satellite, and outputs the satellite orbit data to the satellite orbit storage unit 17. . Further, satellite positioning is performed as necessary, and position data obtained by the positioning is output to the dead reckoning navigation unit 13. The RFID positioning processing unit 152 performs positioning calculation by receiving data from one or more RFIDs installed at a predetermined position. The wireless LAN positioning processing unit 153 receives the data from the wireless LAN base station installed for wireless LAN positioning and performs positioning calculation. This wireless LAN positioning technology includes Hitachi AirLocation (registered trademark). In addition, the positioning calculation unit 15 may include a positioning processing unit corresponding to a positioning method other than those described here.

  The position information display unit 16 displays the position data input from the position correction unit 14. In that case, the position can be shown on the map data displayed on the screen, but at that time, the scale of the display map can be automatically selected by the estimation error of the position data. That is, if the estimation error is small, the scale is reduced and the map is displayed in detail. On the other hand, if the estimation error is large, the scale is enlarged and the map is roughly displayed. The position information display unit 16 is realized by a liquid crystal display or the like. The satellite orbit storage unit 17 stores the satellite orbit data input from the satellite positioning processing unit 151. This satellite orbit data is used when the position correction unit 14 performs position correction. The satellite orbit storage unit 17 is realized by a nonvolatile storage device such as a flash memory or a hard disk device.

  The positioning software storage unit 18 includes a radio frequency signal processing unit 121 and a software signal processing unit 122 of the wireless positioning unit 12, a satellite positioning processing unit 151, an RFID positioning processing unit 152, and a wireless LAN positioning processing unit 153 of the positioning calculation unit 15. Stores such positioning software. The positioning software relates to, for example, signal processing, a demodulation method, correlation processing, and the like. As shown in FIG. 1, the positioning software storage unit 18 is connected to a positioning software distribution server (server) 3 via the network 2 and receives the latest distribution of positioning software from the positioning software distribution server 3 as needed. When the positioning terminal 1 is turned on or necessary, the latest code is supplied to the wireless positioning unit 12 and the positioning calculation unit 15. The positioning software storage unit 18 is realized by a non-volatile storage device such as a flash memory or a hard disk device.

≪ Dead Reckoning ≫
FIG. 2 is a diagram illustrating the principle of the dead reckoning estimation method. The position of the pedestrian (the owner of the positioning terminal 1) is moved step by step (according to the walking motion) using inertial data (measurement data) obtained in time series from the acceleration sensor 111, the angular velocity sensor 112, etc. The direction Ψ _k and the movement position P _k are estimated. This is dead reckoning, which is a method used in the dead reckoning section 13 (see FIG. 1 or FIG. 3). The procedure is shown below.

(1) First, as the initial movement position P ₀ , satellite positioning data from a GPS satellite or the like is used. The initial movement direction Ψ ₀ uses the direction data from the magnetic direction sensor 113.

(2) It is experimentally known that a linear relationship is statistically established between the amplitude of the vertical component of acceleration generated in one cycle of walking motion and the stride. Here, by detecting the walking cycle by analyzing the acceleration data from the acceleration sensor 111 (from the beginning to the end of each step), to estimate the moving distance (step length) s _k.

(3) The movement direction Ψ _k of the pedestrian is estimated by adding the integration (direction change amount) Σω _i of the angular velocity ω _i obtained from the angular velocity sensor 112 by the walking motion for each step in addition to the previous movement direction. The calculation formula is shown in Formula 1.

(4) Then, the moving position of the pedestrian _P k _(x k, _{y k)} for the moving distance (step length) _{s k} in the x direction (east direction) component and the y direction (north), respectively last component of the Is estimated in addition to the x and y coordinates of the movement position. The calculation formula is shown in Formula 2.

  Here, the angular velocity sensor 112 (gyro) is not affected by the magnetic disturbance, and can accurately measure the relative rotation angle for a short time. However, there is a drawback that drift errors accumulate over time. In the low-cost angular velocity sensor 112 that can be used in the positioning terminal 1, in particular, a drift error and an orientation error due to the drift error become remarkable. Accordingly, since the azimuth error and the stride error are integrated at the same time, the position error is accumulated in proportion to the walking time and the walking distance only by dead reckoning. A method for suppressing this increase in error is a hybrid positioning and position correction method, which will be described next.

≪Hybrid positioning and position correction method≫
FIG. 3 is a diagram illustrating a configuration for performing position correction by hybrid positioning in a positioning terminal. Absolute azimuth obtained by magnetic azimuth sensor 113, absolute radio wave obtained from global navigation satellite system (GNSS) or RFID with position information by software radio receiver 19 as a method of suppressing an increase in dead reckoning error Observation data such as position is integrated by the Kalman filter 142. That is, using the observation data different from the dead reckoning navigation, the drift error, the moving azimuth error, the moving distance error and the position error of the angular velocity sensor 112 are simultaneously estimated and corrected. By such correction, the azimuth accuracy and GNSS positioning accuracy of the magnetic azimuth sensor 113 are increased, and the performance of the positioning terminal 1 as pedestrian navigation can be improved.

  Here, although the magnetic direction sensor 113 can stably point to a certain direction and measure the absolute direction, a large error occurs because the geomagnetism is disturbed in the vicinity of an artificial structure such as a reinforcing bar of a building or a track. To do. On the other hand, as GNSS, there are currently GPS and GLONASS, and the service by Galileo and Quasi-Zenith Satellite System (QZSS, Quasi-Zenith Satellite System) will be started in the near future (around 2010). The positioning utilization rate (for example, the probability that positioning is possible) and the positioning accuracy vary greatly depending on whether to use, which signal to use, or whether to use the correction information service. In particular, even if a sufficient number of satellites and correction information services that enable positioning can be secured in urban building streets, the radio waves from the GNSS satellites reflect off the buildings and reach the wireless receiver, so positioning accuracy is high. Decrease significantly.

  Therefore, position correction by hybrid positioning for solving these individual problems and realizing highly accurate positioning will be described in detail.

  As shown in FIG. 3, dead reckoning unit 13 includes a moving distance estimating unit 131, a moving direction estimating unit 132, an absolute direction estimating unit 133, and a position estimating unit 134. The movement distance estimation unit 131 acquires acceleration data from the acceleration sensor 111, estimates the movement distance, and outputs the movement distance to the position estimation unit 134. The method of estimating the movement distance is as described in (2) of << dead reckoning navigation >>. The moving azimuth estimation unit 132 acquires angular velocity data from the angular velocity sensor 112, acquires an absolute azimuth from the magnetic direction sensor 113, estimates the moving azimuth, and uses the moving azimuth as the estimated azimuth, and the position estimation unit 134 and the position correction unit 14 for output. The method of estimating the moving direction is as described in (1) and (3) of << dead reckoning navigation >>.

  The absolute azimuth estimation unit 133 acquires the absolute azimuth from the magnetic azimuth sensor 113, acquires angular velocity data from the angular velocity sensor 112 as necessary, estimates the absolute azimuth, and uses the absolute azimuth as an observation azimuth to correct the position. 14 for output. The position estimation unit 134 inputs the movement distance from the movement distance estimation unit 131, inputs the movement direction from the movement direction estimation unit 132, estimates the movement position, and outputs the movement position to the position correction unit 14 as the estimated position. To do. The estimated position may be directly output to the position information display unit 16. The method for estimating the movement position is as described in (1) and (4) of << dead reckoning navigation >>.

  The software radio receiver 19 includes a radio frequency signal processing unit 121, a software signal processing unit 122 (radio positioning unit 12), and a positioning calculation unit 15. As already described, in the radio positioning unit 12 and the positioning calculation unit 15 of FIG. 1, that is, the software radio receiver 19, the positioning software is loaded from the positioning software storage unit 18 into a predetermined memory and executed by the CPU. It is possible to easily cope with various wireless positioning functions including GNSS positioning. Therefore, a covariance matrix of position observation errors (hereinafter referred to as a position error covariance matrix) is generated for each positioning method, and is output to the position correction unit 14 together with data such as the GNSS position, RFID position, and wireless LAN position.

  The position correction unit 14 receives data such as the estimated position, estimated direction, and observation direction from the dead reckoning unit 13, and receives data such as the position error covariance matrix and GNSS position from the software radio receiver 19, Drift error, moving direction error, and moving position are estimated with high accuracy from the data. The position correction unit 14 includes a subtracter 141, a Kalman filter 142, and a subtractor 143.

  The subtractor 141 subtracts the estimated position input from the position estimating unit 134 of the estimated navigation unit 13 from the GNSS position, RFID position, or wireless LAN position input from the software defined radio receiver 19, and subtracts the subtracted value from the observation residual value. The difference is output to the Kalman filter 142. The subtractor 141 compares the estimated azimuth obtained from the previous movement azimuth and the integration of the angular velocity data by the movement azimuth estimation unit 132 of the estimated navigation unit 13 with the observation azimuth measured by the magnetic direction sensor 113 measured this time. Then, a covariance matrix of azimuth observation errors by the magnetic azimuth sensor 113 (hereinafter referred to as azimuth error covariance matrix) is obtained and output to the Kalman filter 142. According to this, in order to reduce the error of the magnetic direction sensor 113, the estimated direction by the moving direction estimation unit 132 and the observation direction by the magnetic direction sensor 113 can be used as observation data set in the observation equation of the Kalman filter 142. it can.

  The Kalman filter 142 receives the observation residual from the subtractor 141, estimates the position error, and outputs the error to the subtractor 143. On the other hand, the position error covariance matrix is input from the software defined radio receiver 19 and the azimuth error covariance matrix is input from the subtractor 141, and these are set as observation data of the observation equation. Thereby, the accuracy of estimating the position error can be increased. The subtractor 143 subtracts the estimation error input from the Kalman filter 142 from the estimated position input from the position estimation unit 134 of the estimated navigation unit 13 and outputs the subtraction value to the position information display unit 16 as a corrected position.

  According to the above, in the hybrid positioning of the pedestrian navigation by the positioning terminal 1, the error covariance value of the observation equation of the Kalman filter 142 is flexibly provided according to the accuracy of the moving direction and the positioning method by using software radio positioning. By having a structure that can do this, it is possible to estimate the drift error, the moving azimuth error, and the moving position with high accuracy, so that the position accuracy can be improved.

≪Error correction by Kalman filter≫
An error state vector used in error correction by the Kalman filter is shown in Equation 3.

Also, the Kalman filter model is shown in Equation 4.

  The configuration for correcting the error includes an acceleration sensor 111 that detects a walking motion from a pedestrian's motion pattern, an angular velocity sensor 112 that outputs a signal corresponding to a pedestrian's orientation change amount, and a drift amount of the angular velocity sensor 112. Is estimated to determine the amount of azimuth change, the azimuth of the pedestrian is specified by the amount of azimuth change, and the dead reckoning navigation unit 13 that estimates the position of the pedestrian based on this azimuth and stride, and measures the absolute azimuth of the pedestrian The position error is estimated on the basis of the difference between the estimated position and the absolute position, the magnetic direction sensor 113 that performs the measurement, the software radio receiver 19 that receives the satellite radio waves from various GNSS satellites and measures the absolute position of the pedestrian. And a position correction unit 14 that performs correction.

FIG. 4 is a diagram illustrating a model for error correction. In this model, a drift error, an azimuth error, an east-west position error, and a north-south position error are set as a state vector x _k at time t _k , and a state transition matrix Φ _k that gives a temporal change of this error and a signal generation process are generated. Using the noise w _k , the state vector x _{k + 1} and x _k are related by Φ _k x _k + w _k and the state matrix x _k using the observation matrix H _k and the noise v _k generated in the observation process. And an observation process relating the observation vector y _k by H _k x _k + v _k . Based on these, the observation vector y _{k is determined} by the difference between the information on the position and direction of the pedestrian in dead reckoning calculation, the position obtained from the software radio receiver 19 and the direction obtained from the magnetic direction sensor 113. And a state vector x _k is calculated from the model based on the calculated value.

≪Positioning terminal processing≫
FIG. 5 is a flowchart showing a process for interruption of a sensor of a positioning terminal or a software receiver. Each process will be described with reference to FIGS. 1 and 3 as appropriate. First, the walk detection interrupt process will be described. This process is a process for an interrupt that occurs at the detection timing of the acceleration sensor 111 corresponding to each step of the pedestrian. First, according to an instruction from the walking detection interrupt process, the movement distance estimation unit 131 of the estimation navigation unit 13 estimates the movement distance, and the movement direction estimation unit 132 estimates the movement direction (step S501). Next, the position estimation unit 134 calculates the current position and estimates the positioning accuracy (step S502). The calculation result is used as a position error covariance matrix. Then, the absolute azimuth estimation unit 133 estimates the absolute azimuth (step S503). In addition, the process of step S501 and step S502 is called autonomous positioning by dead reckoning navigation.

  Subsequently, the walking detection interrupt process checks whether there is update information of wireless LAN positioning (step S504). This is performed by determining whether there is wireless LAN positioning information that is not reflected in the estimation of positioning accuracy in a predetermined memory. If there is update information (Yes in step S504), a calculation for estimating the positioning accuracy from the update information is performed (step S505). In wireless LAN positioning, since the positioning accuracy, that is, the position error varies depending on the positional relationship between the base station and the positioning terminal 1, the dispersion value of the position error is calculated. The calculation result is a position error covariance matrix. If there is no update information (No in step S504), the process proceeds to step S506.

  Subsequently, the gait detection interrupt process checks whether there is update information of RFID positioning (step S506). This is performed by determining whether there is RFID positioning information that is not reflected in the estimation of positioning accuracy in a predetermined memory. If there is update information (Yes in step S506), a calculation for estimating the positioning accuracy from the update information is performed (step S507). In the RFID positioning, since the positioning accuracy, that is, the position error varies depending on the positional relationship between the RFID and the positioning terminal 1, the dispersion value of the position error is calculated. The calculation result is a position error covariance matrix. If there is no update information (No in step S506), the process proceeds to step S508.

  Subsequently, the gait detection interrupt process checks whether there is update information of satellite positioning (step S508). This is performed by determining whether or not there is satellite positioning information that is not reflected in the estimation of positioning accuracy in a predetermined memory. If there is update information (Yes in step S508), a calculation for estimating the positioning accuracy from the update information is performed (step S509). In satellite positioning, since the positioning accuracy, that is, the position error varies depending on the positional relationship between the positioning satellite and the positioning terminal 1, the dispersion value of the position error is calculated. The calculation result is a position error covariance matrix. If there is no update information (No in step S508), the process proceeds to step S510. In addition, the process of step S504 thru | or step S509 is called software radio positioning.

  And according to the instruction | indication from a walk detection interruption process, the Kalman filter 142 of the position correction part 14 corrects a position (step S510). Thereby, a walk detection interruption process is complete | finished and program control returns to the process which received the interruption.

  Next, the wireless LAN detection interrupt process will be described. This process is a process for an interrupt that occurs when the data input from the wireless positioning unit 12 by the positioning calculation unit 15 relates to the wireless LAN positioning. First, in response to an instruction from the wireless LAN detection interrupt process, the wireless LAN positioning processing unit 153 performs wireless LAN positioning (step S521). Then, the wireless LAN positioning information is stored in a predetermined memory (step S522). This relates to the determination in step S504. As a result, the wireless LAN detection interrupt process ends, and the program control returns to the process that received the interrupt.

  Next, the RFID detection interrupt process will be described. This process is a process for an interrupt that occurs when the data input from the wireless positioning unit 12 by the positioning calculation unit 15 relates to the RFID positioning. First, in response to an instruction from the RFID detection interrupt process, the RFID positioning processing unit 152 performs RFID positioning (step S531). Then, the RFID positioning information is stored in a predetermined memory (step S532). This relates to the determination in step S506. As a result, the RFID detection interrupt process ends, and the program control returns to the process that received the interrupt.

  Further, the timer interrupt process will be described. This process is a process for a timer interrupt that occurs every predetermined time. The time related to this timer interruption is appropriately set from the menu setting contents (positioning conditions) described later. For example, in order to increase the positioning accuracy, the time is set short. In order to keep power consumption low, a long time is set. First, in response to an instruction from the timer interrupt process, the satellite positioning processing unit 151 performs satellite positioning (step S541). Then, the satellite positioning information is stored in a predetermined memory (step S542). This is related to the determination in step S508. As a result, the RFID detection interrupt process ends, and the program control returns to the process that received the interrupt.

  Here, the levels of the wireless LAN detection interrupt, the RFID detection interrupt, and the timer interrupt are the same, but are set to be higher than the level of the walking detection interrupt. As a result, between the wireless LAN detection interrupt process, the RFID detection interrupt process, and the timer interrupt process, another process is performed after one process is completed. Further, during execution of the walking detection interrupt process, another interrupt may occur, and a wireless LAN detection interrupt process, an RFID detection interrupt process, or a timer interrupt process may be performed. According to this, since each positioning information can be updated in a timely manner and kept in the latest state, the latest positioning information can be reflected as much as possible in the estimation of positioning accuracy.

  FIG. 6 is a flowchart showing processing for an interrupt triggered by an instruction from a user of a positioning terminal. The current position request interrupt process is a process for an interrupt generated by an operation when the owner of the positioning terminal 1 performs an operation to instruct display of the current position. First, the dead reckoning navigation unit 13 performs autonomous positioning in accordance with an instruction from the current position request interruption process so that the positioning result is displayed immediately, and the position information display unit 16 displays the positioning result (step S601). . At that time, a scale map corresponding to the positioning accuracy (position error) is displayed on the screen (step S602). According to this, since the positioning terminal 1 always uses the current position information that is always held and updated as needed, instantaneous position display can be performed in response to an instruction from the user. Further, since there is no communication with others, position information can be displayed with low power.

  Subsequently, the positioning calculation unit 15 specifies a positioning method according to an instruction from the current position request interrupt process (step S603). The positioning method can be specified when the positioning terminal 1 selects an optimum positioning method according to the data that can be received at that time, or when the user selects a preferred positioning method. A case will be described in which the user performs menu setting and the positioning terminal 1 specifies a positioning method suitable for the menu setting. As shown in FIG. 6, the degree of preference is set for parameters including positioning time, positioning accuracy, positioning range, and power consumption on the menu setting screen. Then, an optimum positioning method is determined and executed in accordance with the setting contents (positioning conditions). In this case, for example, the setting that the positioning accuracy is high and the power consumption is low is invalid and is a trade-off that cannot be satisfied at the same time. Therefore, it is necessary to set a condition so that either one is given priority.

  The positioning method includes high-accuracy positioning (step S604), low-power positioning (step S605), high-quality positioning (step S606), high-sensitivity indoor positioning (step S607), and the like. High-accuracy positioning is possible by using GPS / QZS satellites (about 33 aircraft) together using QZS reinforcement information. Low power positioning is possible by using a signal called L2C among GPS signals. For high-quality positioning, a GPS / Galileo / QZS satellite (about 63 aircraft) can be used in combination to widen the serviceable range of positioning. High-sensitivity indoor positioning is not necessarily accurate by receiving multipath signals and weak signals, but positioning is performed anyway. The menu setting may be set in advance by the user according to the preference, or may be set together with a position display instruction according to the situation at that time.

  According to the positioning result, position display is performed (step S608). At that time, a map of a scale corresponding to the positioning accuracy is displayed on the screen (step S609). According to this, when the positioning terminal 1 performs position display by autonomous positioning and subsequent position display by the optimum positioning method, the user refers to the approximate position information immediately after instructing the position display. Then, after a predetermined time, it is possible to refer to position information with appropriate accuracy while satisfying a desired positioning condition.

  According to the embodiment of the present invention described above, by installing two or more positioning software in the positioning terminal 1 without changing hardware, two or more wireless signals can be obtained even with a single hardware. The frequency, modulation method, and positioning method can be supported. Further, by downloading the latest code of the positioning software from the positioning software distribution server 3, it is possible to deal with a new radio signal frequency, modulation method, and positioning method. Furthermore, since autonomous positioning is always performed according to the walking motion of the owner of the positioning terminal, the position information can be displayed immediately in response to the instruction of the owner of the positioning terminal 1. In autonomous positioning, since communication with the outside is not performed, a positioning function can be realized with low power.

  Although the embodiment of the present invention has been described above, a program (including a wireless positioning program) executed by each of the positioning terminals 1 shown in FIG. 1 is recorded on a computer-readable recording medium and recorded on this recording medium. The radio positioning terminal according to the embodiment of the present invention is realized by causing the computer to read and execute the program. The program may be provided to the computer via a network such as the Internet.

<< Other embodiments >>
An example of the preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and can be appropriately changed without departing from the spirit of the present invention. For example, in the above-described embodiment, the configuration in which the autonomous positioning and the wireless positioning are used together is described, but the configuration using only the wireless positioning may be used. In this case, the positioning terminal 1 includes a wireless positioning unit 12, a positioning calculation unit 15, a position information display unit 16, and a positioning software storage unit 18 as a minimum configuration. According to this configuration, by installing two or more positioning software without changing the hardware, even a single hardware can handle two or more radio signal frequencies, modulation schemes, and positioning schemes. A positioning terminal can be realized.

It is a figure which shows the structure of the positioning terminal which concerns on embodiment of this invention, and its periphery. It is a figure which shows the principle of the estimation method of dead reckoning. It is a figure which shows the structure for performing the position correction by hybrid positioning in a positioning terminal. It is a figure which shows the model for error correction. It is a flowchart which shows the process with respect to the interruption of the sensor of a positioning terminal, or a software receiver. It is a flowchart which shows the process with respect to the interruption which uses the instruction | indication of the user of a positioning terminal as a trigger.

Explanation of symbols

1 Positioning terminal 3 Positioning software distribution server (server)
DESCRIPTION OF SYMBOLS 11 Autonomous positioning part 111 Acceleration sensor 112 Angular velocity sensor 113 Magnetic direction sensor 12 Wireless positioning part 13 Dead reckoning part 131 Movement distance estimation part 132 Movement direction estimation part 134 Position estimation part 14 Position correction part 15 Positioning calculation part 16 Position information display part 18 Positioning software storage (software storage)

Claims (5)

A radio positioning unit that receives a positioning radio signal, demodulates the received radio signal, and outputs the demodulated positioning data;
A positioning calculation unit that inputs the positioning data from the wireless positioning unit, performs a positioning calculation according to the input positioning data, and outputs position information as a result of the positioning calculation;
A position information display unit for inputting and displaying the position information from the positioning calculation unit;
A positioning terminal comprising:
A software storage unit for storing first software corresponding to the frequency and modulation scheme of the radio signal and second software corresponding to the positioning scheme related to the positioning data;
In the wireless positioning unit, the CPU loads the first software from the software storage unit into a predetermined memory, and executes the first software according to the frequency and modulation method of the wireless signal,
In the positioning calculation unit, the CPU loads the second software from the software storage unit to a predetermined memory and executes the second software according to a positioning method related to the positioning data. The software storage unit is connected to a server that distributes the first software and the second software, and receives and updates the first software and the second software from the server. The positioning terminal according to claim 1. The positioning terminal according to claim 1 or 2, wherein the positioning calculation unit inputs positioning conditions set by a user and specifies a positioning method suitable for the positioning conditions. The positioning terminal is
An autonomous positioning unit that consists of an acceleration sensor, an angular velocity sensor, and a magnetic orientation sensor, and outputs measurement data from each sensor;
The dead reckoning navigation unit that inputs the measurement data from the autonomous positioning unit, estimates the position of the positioning terminal from the measurement data, and outputs the position information;
Position information is input from the positioning calculation section, position information is input from the dead reckoning navigation section, position error is estimated from the position information, position information is corrected by the position error, and the corrected position information is A position correction unit for outputting to the position information display unit;
Further comprising
The acceleration sensor outputs acceleration data to the dead reckoning navigation unit according to the walking motion of the owner of the positioning terminal,
The angular velocity sensor outputs angular velocity data to the dead reckoning navigation unit according to the walking movement of the owner of the positioning terminal,
The dead reckoning part is
A movement distance estimation unit that inputs the acceleration data from the acceleration sensor, estimates a movement distance from the acceleration data, and outputs the movement distance;
A moving direction estimation unit that inputs the angular velocity data from the angular velocity sensor, inputs an absolute direction at that time from the magnetic direction sensor, estimates a moving direction from the angular velocity data and the absolute direction, and outputs the moving direction; ,
The moving distance is input from the moving distance estimating unit, the moving direction is input from the moving direction estimating unit, the moving position is estimated from the moving distance and moving direction, and the moving position is output to the position correcting unit. A position estimation unit to perform,
With
The positioning terminal according to any one of claims 1 to 3, wherein the position information display unit inputs and displays the position information from the position correction unit. The position correction unit outputs the estimated position error to the position information display unit,
The position information display unit receives the position information and a position error from the position correction unit, and displays the position information on map data of a scale selected according to the position error. 4. The positioning terminal according to 4.

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