Abstract:
In order to acquire positioning results (position and azimuth) of a moving body and reducing cumulative errors in integration processing of the positioning results, a moving body positioning apparatus includes: movement detecting means for detecting whether or not a moving body is moving; position acquiring means for acquiring a position of the moving body; integrating means for integrally processing a plurality of positions acquired by the position acquiring means as positioning results; and preprocessing means for preprocessing the positioning results to be inputted into the integrating means. In accordance with output from the movement detecting means, the preprocessing means inputs the positioning results obtained from the position acquiring means into the integrating means, which integrally processes the positioning results.

Description:
TECHNICAL FIELD 
     The present invention relates to a moving body positioning apparatus capable of measuring the position and azimuth of a moving body and reducing cumulative errors in integrally processing the positioning results thus acquired. 
     BACKGROUND ART 
     A technique for acquiring the position and azimuth of a person through a body-worn system in which the person wears an electronic system containing a sensor is essential to the realization of an intellectual interface with a computer through a grasp of context information on the person. Such a technique is expected to be developed to have many applications in pedestrian navigation, grasping of the situation of workers during remote operation assistance, guiding of visitors thorough exhibitions in museums or large-scale exhibition facilities, etc. 
     Moreover, various extended techniques have brought about improvement in positioning accuracy of the GPS (Global Positioning System). However, depending on the line-of-sight distance of GPS satellites and multipath errors, the extended techniques cannot give sufficient accuracy and, what is more, face difficulties in being used in indoor environments. A car navigation system, which is a moving body positioning apparatus, uses radio signals from GPS satellites to measure the position of a vehicle in which the system has been installed and, furthermore, uses a vehicle speed sensor, a gyro sensor, etc. to estimate the current position of the vehicle while accumulating distances and directions the vehicle has traveled. 
     In a situation where the car navigation system cannot receive radio signals from GPS satellites, errors contained in positioning according to autonomous navigation are amplified over time; therefore, there is a gradual decrease in accuracy of position. For this reason, there have been proposed various methods, as disclosed in Patent Literature 1, for correcting the position of a vehicle positioned by autonomous navigation. For example, map matching is carried out, using map data stored in a navigation system, to correct a position measured by autonomous navigation (Patent Literature 1). 
     CITATION LIST 
     Patent Literature 1 
     Japanese Patent Application Publication, Tokukai, No. 2002-213979 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     When, in a moving body positioning apparatus, a series of position measurement results is obtained through positioning means using radio signals such as a wireless IC tag or the GPS, an infrared beacon device, a motion analysis by external camera, etc., highly reproducible positioning results are often repeatedly obtained, as long as a moving body is present at the same point. 
     However, errors in the positioning results are often not deemed as white noise whose mean vector is zero, and the errors are often accompanied by offsets depending on places of positioning. For the purpose of position estimation processing, it is desirable that input into a Kalman filter, a particle filter, etc. assume character of an error having a quality of white noise whose mean is zero. However, in such a situation as mentioned above, continuous input of the positioning results as observations into a Kalman filter, a particle filter, etc. ends up in inaccurate positioning results displaced by the offset errors. 
     Alternatively, in an absolute azimuth acquisition apparatus for acquiring the absolute azimuth of a moving body with reference to geomagnetism, a highly reproducible absolute azimuth is often repeatedly acquired, as long as the moving body is present at the same point. However, if the absolute azimuth is out of alignment with true magnetic north, for example, due to the presence of a magnetic body nearby, such an error cannot be deemed as white noise whose means is zero. Therefore, it is inappropriate, by the same token, to integrate positioning results by inputting them into a Kalman filter, a particle filter, etc. 
     The present invention has been made in order to solve such problems, and it is an object of the present invention to provide a moving body positioning apparatus capable of acquiring positioning results (position and azimuth) of a moving body and reducing cumulative errors in integrally processing the positioning results. 
     Solution to Problem 
     In order to attain such an object as stated above, the present invention configures a moving body positioning apparatus based on such a concept as follows: Because positioning results obtained by a wireless IC tag, the GPS, etc. in an interval of movement over a distance longer than or equal to a predetermined threshold value are not those obtained at the same point but those obtained in moment-to-moment varying conditions and environments, errors in observation data are expected to be closer in character to a quality of white noise whose mean vector is 0. For this reason, a series of positioning results that are obtained during movement is considered as data more appropriate in character to be input into a Kalman filter, a particle filter, etc. 
     In view of this, the present invention makes it possible to measure the position of a moving body more appropriately by detecting movements to discriminate between two states, namely a state where the moving body is moving and a state where the moving body is at rest, and by differently dealing with positioning results obtained in the respective states. 
     Further, in cases where the moving body positioning apparatus of the present invention makes absolute azimuth measurements, absolute azimuth measurement results obtained according to geomagnetism in an interval of movement over a distance longer than or equal to a predetermined threshold value are not those obtained at the same point but those obtained in moment-to-moment varying conditions and environments. Therefore, errors in observation data are expected to be closer in character to a quality of white noise whose mean vector is 0. For this reason, a series of absolute azimuth measurement results that are obtained during movement serves as data more appropriate in character to be inputted into a Kalman filter, a particle filter, etc. for integrated processing. In view of this, the present invention makes it possible to measure the absolute azimuth of a moving body more appropriately by detecting movements to discriminate between two states, namely a state where the moving body is moving and a state where the moving body is at rest, and by differently dealing with absolute azimuth measurement results obtained according to geomagnetic in the respective states. 
     Specifically, in a first aspect of the present invention, a moving body positioning apparatus includes: movement detecting means for detecting whether or not a moving body is moving; position acquiring means for acquiring a position of the moving body; integrating means (which may be a processor) for integrally processing a plurality of positions acquired by the position acquiring means as positioning results; and preprocessing means (which may be the same or a different processor) for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the movement detecting means, the preprocessing means inputting positioning results obtained from the position acquiring means into the integrating means, which integrally processes the positioning results. 
     Further, in a second aspect of the present invention, a moving body positioning apparatus includes: movement speed measuring means for measuring a movement speed of a moving body; position acquiring means for acquiring a position of the moving body; integrating means for integrally processing a plurality of positions acquired by the position acquiring means as positioning results; and preprocessing means for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the movement speed measuring means, the preprocessing means inputting positioning results obtained from the position acquiring means into the integrating means, which integrally processes the positioning results. 
     Further, in a third aspect of the present invention, a moving body positioning apparatus includes: movement speed measuring means for measuring a movement speed of a moving body; position acquiring means for acquiring a position of the moving body; integrating means for integrally processing a plurality of positioning results acquired by the position acquiring means and results of measurement of the movement speed by the movement speed measuring means; and preprocessing means for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the movement speed measuring means, the preprocessing means inputting positioning results obtained from the position acquiring means into the integrating means, which integrally processes the positioning results. 
     Further, in a fourth aspect of the present invention, a moving body positioning apparatus includes: travel distance measuring means for measuring a travel distance that a moving body has traveled; integrating means for integrally processing a plurality of positions acquired by the position acquiring means as positioning results; and preprocessing means for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the travel distance measuring means, the preprocessing means inputting positioning results obtained from the position acquiring means into the integrating means, which integrally processes the positioning results. 
     Further, in a fifth aspect of the present invention, a moving body positioning apparatus includes: movement detection means for detecting whether or not a moving body is moving; absolute azimuth acquiring means for acquiring an absolute azimuth of the moving body; integrating means for integrally processing azimuth estimate results estimated from a plurality of absolute azimuths acquired by the absolute azimuth acquiring means as positioning results; and preprocessing means for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the movement detecting means, the preprocessing means inputting absolute azimuth estimate results obtained from the absolute azimuth acquiring means into the integrating means, which integrally processes the azimuth estimate results. 
     Further, in a sixth aspect of the present invention, a moving body positioning apparatus includes: movement speed measuring means for measuring a movement speed of a moving body; absolute azimuth acquiring means for acquiring an absolute azimuth of the moving body; integrating means for integrally processing azimuth estimate results estimated from a plurality of absolute azimuths acquired by the absolute azimuth acquiring means as positioning results; and preprocessing means for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the movement speed measuring means, the preprocessing means inputting absolute azimuth estimate results obtained from the absolute azimuth acquiring means into the integrating means, which integrally processes the azimuth estimate results. 
     Further, in a seventh aspect of the present invention, a moving body positioning apparatus includes: travel distance measuring means for measuring a travel distance that a moving body has traveled; absolute azimuth acquiring means for acquiring an absolute azimuth of the moving body; integrating means for integrally processing azimuth estimate results estimated from a plurality of absolute azimuths acquired by the absolute azimuth acquiring means as positioning results; and preprocessing means for preprocessing positioning results that are to be inputted into the integrating means, in accordance with output from the travel distance measuring means, the preprocessing means inputting absolute azimuth estimate results obtained from the absolute azimuth acquiring means into the integrating means, which integrally processes the azimuth estimate results. 
     In these cases, position information acquired by the position acquiring means is position information that is not guaranteed to assume character of an error having a quality of white noise whose mean vector is zero, and azimuth information acquired by the absolute azimuth acquiring means is azimuth information that is not guaranteed to assume character of an error having a quality of white noise whose mean vector is zero. 
     Advantageous Effects of Invention 
     A moving body positioning apparatus of the present invention can detect whether or not a moving body is moving, select, in accordance whether or not the moving body is moving, data whose positions and azimuths are to be corrected as positioning results of the moving body, and process the data. 
     When, in a moving body positioning apparatus, positioning results of a moving body as obtained by a wireless IC tag or the GPS for use in acquisition of an absolute position, an infrared beacon device, a motion analysis by external camera, etc. are inputted into a Kalman filter, a particle filter, etc., the data to be inputted can be appropriately selected. When absolute azimuth estimate results obtained according to geomagnetism are inputted into a Kalman filter, a particle filter, etc., the data to be inputted can be appropriately selected particularly effectively. 
     This makes it possible, as a result, to select, from a series of data on positioning results, obtained by a wireless IC tag or the GPS, which do not assume character of an error having a quality of white nose whose mean vector is zero, appropriate data that can be inputted into a Kalman filter or a particle filter, and to input the positioning results for integrated processing. 
     This also makes it possible to select, from a series of data on positioning results, obtained according to geomagnetism, which do not assume character of an error having a quality of white nose whose mean vector is zero, appropriate data that can be inputted into a Kalman filter or a particle filter, and to input the positioning results for integrated processing. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram showing a basic configuration of a moving body positioning apparatus according to the present invention. 
         FIG. 2  is a flow chart showing the content of data processing in a preprocessing section  703 . 
         FIG. 3  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. 
         FIG. 4  is a flow chart showing the content of data processing in a preprocessing section  803 . 
         FIG. 5  is a block diagram showing a configuration of still another moving body positioning apparatus according to the present invention. 
         FIG. 6  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. 
         FIG. 7  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. 
         FIG. 8  is a flow chart showing the content of data processing in a preprocessing section  903 . 
         FIG. 9  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. 
         FIG. 10  is a flow chart showing the content of data processing in a preprocessing section  1303 . 
         FIG. 11  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. 
         FIG. 12  is a flow chart showing the content of data processing in a preprocessing section  1603 . 
         FIG. 13  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. 
         FIG. 14  is a flow chart showing the content of data processing in a preprocessing section  1903 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A moving body positioning apparatus according to an embodiment of the present invention is described below in detail with reference to the drawings.  FIG. 1  is a block diagram showing a basic configuration of a moving body positioning apparatus according to the present invention. In  FIG. 1 , reference numerals  102 ,  104 ,  701 , and  703  indicate position measuring means, positioning result integrating means, movement detecting means, and a preprocessing section, respectively. Reference numerals  110 ,  711 ,  712 , and  713  indicate position information, a movement detection signal, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     The movement detecting means  701  is a measuring device that is mounted to a moving body to detect whether or not the moving body is moving. Alternatively, the movement detecting means  710  is a measuring device that observes a moving body from outside to detect whether or not the moving body is moving. When the moving body is moving, the movement detecting means  701  outputs a movement detection signal  711  whose movement flag is TRUE. Alternatively when the moving body is at rest, the movement detecting means  701  outputs a movement detection signal  711  whose movement flag is FALSE. In cases where the moving body is an automobile or a mobile robot, the movement detecting means  701  is embodied, for example, by a wheel rotary encoder or a car speed pulse (odometer) generator. Alternatively, in cases where the moving body is a pedestrian, the movement detecting means  701  is embodied by an acceleration sensor that detects the walking movement of the pedestrian, a pedometer, etc. 
     Alternatively, the movement detecting means  701  can also be embodied by a device that detects the status of movement by using a computer to analyze an image taken by an external camera monitoring a moving body. Alternatively, the movement detecting means  701  can also be embodied by an inertial navigation system (INS), combined with an inertial sensor, which can be applied to any moving body. 
     The position measuring means  102  is measuring means that either is mounted to a moving body or observes a moving body from outside to measure the position of the moving body. The position measuring means  102  is embodied, for example, by a position detection device such as the GPS or a wireless IC tag, an inertial navigation system (INS), a dead-reckoning device based on walking movement, etc. Alternatively, the position measuring means  102  can also be constituted by a data-processing device that estimates the position of a moving body through observation by external camera. 
     The position measuring means  102  measures the current position of the moving body and outputs position information  110  thus measured. Such position information  110  outputted by the position measuring means  102  may contain the uncertainty of the position information. The preprocessing section  703  determines, with reference to a movement detection signal  711  obtained as a result of detection of whether or not the moving body is moving, whether position information  110  obtained as a positioning result of the moving body should be used, and outputs appropriate position information. 
     The preprocessing section  703  mainly executes a data selection process on a processor. When it is determined that the moving body is at rest, i.e., when a movement detection signal  711  obtained a result of detection of whether or not the moving body is moving is outputted as a FALSE signal, the preprocessing section  703  carries out a process of skipping second and subsequent pieces of data on position information  110  obtained from the position measuring means  102  as positioning results. 
     That is, even if plural pieces of position information  110  are obtained as positioning results observed when the moving body was at rest, the preprocessing section  703  selects one of them as a representative, and outputs it when a movement detection signal  711  obtained as a result of detection of whether or not the moving body is moving is outputted as TRUE. When the pieces of position information  110  obtained contain information about uncertainty, the preprocessing section  703  may take out position information with the least uncertainty during the data selection process. 
     In this way, only position information selected by the preprocessing section  703  is outputted as a preprocessing signal  712 . The positioning result integrating means  104  integrates a plurality of positioning results obtained from the position measuring means  102  as positioning results of the moving body into one final positioning result and outputs it as an integrated signal  713 . 
     In this case, position information  110  obtained from the position measuring means  102  as a plurality of positioning results is that which is obtained, for example, by a positioning device based on the GPS, a wireless IC tag, or infrared signal beacons, an inertial navigation system (INS), a dead-reckoning device based on walking movement, a device for motion analysis by external camera, etc. The positioning result integrating means  104 , which integrates these positioning results, carries out a process of integrating positioning results, for example, through a Kalman filter, a particle filter, etc. These processes are publicly known, and as such, are not described in detail. 
     The positioning result integrating means  104  receives, as a preprocessing signal  712 , position information  110  selected by the preprocessing section  712  as a positioning result. The positioning result integrating means  104  incorporates the preprocessing signal  712  as input, updates its internal positioning result, and, by using the result as position information, outputs a final positioning result as an integrated signal  713 . In cases where the positioning result integrating means  104  is embodied by a Kalman filter, a particle filter, etc. on a processor, the integrated signal  713 , i.e., the final positioning result may be output containing uncertainty about the position. 
       FIG. 2  is a flow chart showing the content of data processing in the preprocessing section  703 . An explanation is given with reference to  FIG. 2 . When the process is started, first, in Step S 1001 , the preprocessing section  703  receives from the movement detecting means  701  a movement detection signal  711  representing whether or not a moving body is moving and receives position information  110  on the moving body from the position measuring means  102 . In Step S 1001 , the position information  110  thus received is accumulated in a storage device for future use. Next, in Step S 1003 , the preprocessing section  703  determines whether or not the movement detection signal  711  has a TRUE movement flag. If the movement detection signal  711  has a TRUE movement flag, the preprocessing section  703  executes Step S 1004 . Alternatively, if the movement detection signal  711  has a FALSE movement flag, the preprocessing section  703  executes Step S 1005 . 
     In Step S 1004 , if position information  110  obtained from the position measuring means  102  contains information about uncertainty, position information  713  with the least uncertainty is outputted. When the movement detection signal  711  has a FALSE movement flag, Step S 1005  is executed. In Step S 1005 , no position information is outputted, that is, information indicative of the absence of output is presented. The process returns to Step S 1001  to start all over again from Step S 1001 . 
       FIG. 3  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. In  FIG. 3 , reference numerals  102 ,  104 ,  801 , and  803  indicate position measuring means, positioning result integrating means, movement speed measuring means, and a preprocessing section, respectively. Reference numerals  110 ,  811 ,  812 , and  113  indicate position information, movement speed information, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     In the block diagram of  FIG. 3 , the moving body positioning apparatus includes movement speed measuring means  801  for measuring the movement speed of a moving body, instead of including movement detecting means. The movement speed measuring means  801  is a device that either is mounted to a moving body or uses external observation means to measure the speed of the moving body and output movement speed information  811 . In cases where the moving body is an automobile or a mobile robot, the movement speed measuring means  801  is constituted using a wheel rotary encoder or a car speed pulse (odometer). Alternatively, in cases where the moving body is a pedestrian, the movement speed measuring means  801  is constituted using an acceleration sensor that detects the walking movement of the pedestrian. 
     Alternatively, the movement speed measuring means  801  can also be embodied by a device that measures the movement speed of a moving body by analyzing an image taken by a camera installed outside to monitor the moving body. Alternatively, the movement speed measuring means  801  can principally measure the movement speed of any moving body by using an inertial navigation system (INS). 
     The position measuring means  102  is measuring means that either is mounted to a moving body or observes a moving body from outside to measure the position of the moving body. As mentioned above, the position measuring means  102  is embodied, for example, by a position detection device such as the GPS or a wireless IC tag, an inertial navigation system (INS), a dead-reckoning device based on walking movement, etc. Alternatively, the position measuring means  102  can also be constituted by a data-processing device that estimates the position of a moving body through observation by external camera. The position measuring means  102  measures the position of the moving body and outputs position information  110  on the moving body. Such position information  110  thus outputted may contain the uncertainty of the position information. 
     The preprocessing section  803  carries out preprocessing mainly as a data selection process. In this case, the preprocessing section  803  receives movement speed information  811  from the movement speed measuring means  801 , calculates in accordance with the movement speed information  811  a travel distance that the moving body has traveled, and selects from data on positioning results from the position measuring means  102  in accordance with the travel distance thus calculated. 
     That is, in an initial state where the preprocessing section  803  has not outputted position information  110  at all by receiving position information  110  from the position measuring means  102 , the preprocessing section  803  outputs the received position information  110  as its preprocessing signal  812 . In cases where the preprocessing section  803  outputted position information  110  in the past, the preprocessing section  803  calculates a travel distance from a movement speed signal  811  and, furthermore, calculates a distance that the moving body has traveled since the last output, in which case if the distance thus calculated is less than or equal to a predetermined threshold value, the preprocessing section  803  selects one of the pieces of previously received position information  110  as a representative value and outputs it as a preprocessing signal  812 . 
     In cases where the pieces of position information  110  contain uncertainties, the preprocessing section  803  outputs position information  110  with the least uncertainty as a preprocessing signal  812 . As mentioned above, the positioning result integrating means  104  integrates a plurality of positioning results of the moving body into one final positioning result and outputs it. 
       FIG. 4  is a flow chart showing the content of data processing in the preprocessing section  803 . An explanation is given with reference to  FIG. 4 . When the process is started, first, in Step S 1101 , the preprocessing section  803  receives movement speed information  811  on a moving body from the movement speed measuring means  801  and receives position information  110  from the position measuring means  102 . In Step S 1101 , the position information  101  thus received is accumulated in a storage device for future use. Next, in Step S 1102 , the preprocessing section  803  time-integrates movement speeds of the moving body in accordance with the movement speed information  811  and calculates a travel distance that the moving body has traveled since the last output of position information. Next, in Step S 1103 , the preprocessing section  803  determines whether or not the travel distance thus calculated is greater than or equal to a predetermined threshold value. If the travel distance is greater than the predetermined threshold value, the preprocessing section  803  executes Step S 1104  to output position information in accordance with the position information  101  thus received. In cases where the position information thus received has been given information on uncertainty, the preprocessing section  803  outputs position information with the least uncertainty as a preprocessing signal  812  in accordance with the recording of accumulation of previously received position information. If, in Step S 1103 , the preprocessing section  803  determines that the travel distance is not greater than the predetermined threshold value, the preprocessing section  803  executes Step S 1105 . However, the preprocessing section  803  does not produce any output, i.e., outputs information indicative of the absence of output as a preprocessing signal  812 . 
       FIG. 5  is a block diagram showing a configuration of still another moving body positioning apparatus according to the present invention. In  FIG. 5 , reference numerals  102 ,  104 ,  1701 ,  1702 , and  803  indicate position measuring means, positioning result integrating means, walking speed measuring means, an acceleration sensor, and a preprocessing section, respectively. Reference numerals  110 ,  811 ,  812 , and  113  indicate position information, movement speed information, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     The block diagram of  FIG. 5  shows a configuration of a moving body positioning apparatus for measuring a position of movement of a person. The moving body positioning apparatus includes walking speed measuring means  1701  and an acceleration sensor  1702 , instead of including the movement speed measuring means  801  of  FIG. 3 . 
     That is, the moving body positioning apparatus of  FIG. 5  is obtained by replacing the movement speed measuring means  801  of  FIG. 3  for measuring the movement speed of a moving body with the walking speed measuring means  1701  for measuring the walking speed of a person. In this embodiment, the moving body is supposed to be a pedestrian. The walking speed measuring means  1701  calculates a walking speed by receiving acceleration output  1710  from the acceleration sensor  1702 . The calculation of a walking speed based on acceleration is described in Japanese Patent Application Publication, Tokukai, No. 2005-114537, which relates to an invention of the inventors of the present invention. Other components of the moving body positioning apparatus are the same as those described with reference to  FIGS. 3 and 4 , and as such, as not described. 
       FIG. 6  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention obtained by configuring the moving body positioning apparatus of  FIG. 3  such that the movement speed of a moving body as measured by the movement speed measuring means  801  is inputted into positioning result integrating means  1504 . In  FIG. 6 , reference numerals  102 ,  1504 ,  801 , and  803  indicate position measuring means, positioning result integrating means, movement speed measuring means, and a preprocessing section, respectively. Reference numerals  110 ,  811 ,  812 , and  113  indicate position information, movement speed information, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     The movement speed measuring means  801  here is means for measuring the movement speed of a moving body, as with the movement measuring means  801  of  FIG. 3 . In the moving body positioning apparatus thus configured, the movement speed measuring means  801  not only outputs movement speed information  811  on a moving body as input into the preprocessing section  803 , which carries out a data selection process, but also outputs movement speed information  811  as direct input into the positioning result integrating means  1504 . The positioning result integrating means  1504  is integrating means for integrally processing positioning results and, at the same time, is configured to be able to use a movement speed to update its internal state and embodied, for example, by a configuration of a Kalman filter which can be used for observation to update its internal state. Functions of the position measuring means  102 , which measures the position of a moving body, and the preprocessing section  803  are the same as those described with reference to  FIG. 3 . 
       FIG. 7  is a block diagram showing a configuration of another moving body positioning apparatus according to the present invention. In  FIG. 7 , reference numerals  102 ,  104 ,  901 , and  903  indicate position measuring means, positioning result integrating means, travel distance measuring means, and a preprocessing section, respectively. Reference numerals  110 ,  911 ,  912 , and  113  indicate position information, travel distance information, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     In the block diagram of  FIG. 7 , the moving body positioning apparatus includes travel distance measuring means  901  for measuring a travel distance that a moving body has traveled, instead of including the movement detecting means  701 . The travel distance measuring means  901  used here is measuring means for measuring and outputting a relative travel distance. For example, the travel distance measuring means  901  can be embodied by a measuring device capable of obtaining a relative travel distance by using a difference between positioning results obtained by the GPS. Alternatively, in cases where the moving body is an automobile, the travel distance measuring means  901  can be embodied by a measuring device that obtains output of a travel distance from the radius of each wheel by a car speed pulse or a wheel rotary encoder. Alternatively, the same output can be obtained by a device (e.g., an inertial navigation system) that calculates a relative travel distance by integrating movement speeds. Alternatively, in cases where the moving body is a pedestrian, the travel distance measuring means  901  can be embodied by a measuring device using a technique capable of acquiring a travel distance from the length of stride of a pedestrian and output of an acceleration sensor. 
     The travel distance measuring means  901  outputs relative travel distance information  911 . The position measuring means  102  measures the position of a moving body and outputs position information  110  on the moving body. Such position information  110  thus outputted may contain the uncertainty of the position information. The preprocessing section  903  receives position information  110  from the position measuring means  102 , and outputs first received position information  110  as a preprocessing signal  912 . In cases where the preprocessing section  903  outputted position information  110  in the past, the preprocessing section  903  calculates a distance that the moving body has traveled from a reference position at which the last position information  110  was outputted. If the distance thus calculated is less than or equal to a predetermined threshold value, the preprocessing section  903  selects one of the pieces of previously received position information  110  as a representative value and outputs it as a preprocessing signal  912 . As with the aforementioned configuration, the positioning result integrating means  104  integrates a plurality of positioning results of the moving body into one final positioning result and outputs it. 
       FIG. 8  is a flow chart showing the content of data processing the preprocessing section  903 . An explanation is given with reference to  FIG. 8 . When the process is started, first, in Step S 1201 , the preprocessing section  903  receives travel distance information  911  on a moving body from the travel distance measuring means  901  and receives position information  110  from the position measuring means  102 . In Step S 1201 , the position information  101  thus received is accumulated in a storage device for future use. Next, in Step S 1202 , the preprocessing section  903  calculates a travel distance that the moving body has traveled from a position at which the previous position information was outputted. 
     Next, in Step S 1203 , the preprocessing section  903  determines whether or not the travel distance thus calculated is greater than a predetermined threshold value. If the travel distance is greater than the predetermined threshold value, the preprocessing section  903  executes Step S 1204  to output position information in accordance with the position information thus received. In cases where the position information thus received has been given information on uncertainty, the preprocessing section  903  outputs position information with the least uncertainty as a preprocessing signal  912  in accordance with the recording of accumulation of previously received position information. If, in Step S 1203 , the preprocessing section  803  determines that the travel distance is not greater than the predetermined threshold value, the preprocessing section  903  executes Step S 1205 . However, the preprocessing section  903  does not output any position information, i.e., outputs information indicative of the absence of output as a preprocessing signal  912 . 
       FIG. 9  is a block diagram of a configuration of another moving body positioning apparatus according to the present invention. In  FIG. 9 , reference numerals  1302 ,  1304 ,  1301 , and  1303  indicate absolute azimuth measuring means, absolute azimuth measurement result integrating means, movement detecting means, and a preprocessing section, respectively. Reference numerals  1310 ,  1311 ,  1312 , and  1313  indicate absolute azimuth measurement information, a movement detection signal, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     The movement detecting means  1301  is a measuring device mounted to a moving body or a measuring device that observes a moving body from outside. This device is identical to the movement detecting means  701  of the configuration described with reference to  FIG. 1 . When the moving body is moving, the movement detecting means  1301  outputs a movement detection signal  1311  whose movement flag is TRUE. Alternatively, when the moving body is at rest, the movement detecting means  1301  outputs a movement detection signal  1311  whose movement flag is FALSE. The absolute azimuth measuring means  1302  is a measuring device that measures and outputs the azimuth angle of a moving body. The absolute azimuth measuring means  1302  is embodied, for example, by an electronic compass (combination of a magnetic sensor and an acceleration sensor), etc. 
     The preprocessing section  1303 , which carries out a data selection process, receives a movement detection signal  1311  from the movement detecting means  1301  and receives absolute azimuth measurement information  1310  from the absolute azimuth measuring means  1302 . The absolute azimuth measurement information  1310  may contain uncertainty about the absolute azimuth. When the movement detection signal  1311 , which is a signal that indicates whether or not the moving body is moving, is a FALSE movement flag, i.e., when it is determined that the moving body is at rest, the preprocessing section  1303  carries out a process of skipping second and subsequent pieces of absolute azimuth input  1310 . 
     Alternatively, when the movement detection signal  1311  is TRUE, i.e., when it is determined that the moving body is moving, the preprocessing section  1303  selects a representative one of plural pieces of input of absolute azimuth measurement information  1310  observed when the moving body was at rest. When the pieces of absolute azimuth measurement information  1310  contain information about uncertainty, the preprocessing section  1303  selects out absolute azimuth with the least uncertainty. 
     The absolute azimuth measurement result integrating means  1304  receives measurement results from a plurality of absolute azimuth measuring means  1302 , integrates the measurement results into one final absolute azimuth estimate result, and outputs the final absolute azimuth estimate result as an integrated signal  1313 . The plurality of absolute azimuth measuring means  1302  can be embodied, for example, by means for integrating signals obtained by gyro sensor (angular velocity sensor) to measure a relative azimuth angle with respect to a reference azimuth angle. The absolute azimuth measurement result integrating means  1304 , which integrates these estimate results, can be constituted, for example, by a Kalman filter, a particle filter, etc. The absolute azimuth measurement result integrating means  1304  receives the absolute azimuth selected by the preprocessing section  1303 , i.e., receives a preprocessing signal  1312  from the preprocessing section  1303 , updates its internal state, and outputs a final absolute azimuth estimate result  1313  in accordance with input from the other absolute azimuth measuring means and its internal state. 
       FIG. 10  is a flow chart showing the content of data processing in the preprocessing section  1303 . An explanation is given with reference to  FIG. 10 . When the process is started, first, in Step S 1401 , the preprocessing section  1303  receives from the movement detecting means  1301  a movement detection signal  1311  representing whether or not the moving body is moving and receives absolute azimuth measurement information  1310  from the absolute azimuth measuring means  1302 . The absolute azimuth  1310  here may contain information on its uncertainty. Next, in Step S 1403 , the preprocessing section  1303  determines whether or not the movement detection signal  311  has a TRUE movement flag. If the movement detection signal  1311  has a TRUE movement flag, the preprocessing section  1303  executes Step S 1404 . Alternatively, if the movement detection signal  1311  has a FALSE movement flag, the preprocessing section  1303  executes Step S 1405 . In Step S 1404 , the preprocessing section  1303  outputs absolute azimuth information as a preprocessing signal  1312 . In Step S 1405 , the preprocessing section  1303  notifies that it does not output any absolute azimuth information as a preprocessing signal  1312 . Then, the process returns to Step S 1401  to start all over again from Step S 1401 . 
       FIG. 11  is a block diagram of a configuration of another moving body positioning apparatus according to the present invention. In  FIG. 11 , reference numerals  1602 ,  1304 ,  1601 , and  1603  indicate absolute azimuth measuring means, absolute azimuth measurement result integrating means, movement speed measuring means, and a preprocessing section, respectively. Reference numerals  1310 ,  1611 ,  1612 , and  1313  indicate absolute azimuth measurement information, movement speed measurement information, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     The movement speed measuring means  1601  is a device that either is mounted to a moving body or uses external observing means to measure the speed of the moving body and output movement speed measurement information  1611 . In cases where the moving body is an automobile, the movement speed measuring means  1601  is embodied by a wheel rotary encoder or a car speed pulse (odometer). Alternatively, in cases where the moving body is a pedestrian, the movement speed measuring means  1601  is constituted using an acceleration sensor that detects the walking movement of the pedestrian, as proposed by the inventors of the present invention in their previous patent application. Alternatively, the movement speed measuring means  1601  can be embodied by a device that measures the movement speed of a moving body by analyzing an image taken by a camera installed outside to monitor the moving body. Alternatively, the movement speed measuring means  1601  can principally measure the movement speed of any moving body by using an inertial navigation system (INS). 
     As mentioned above, the absolute azimuth measuring means  1302  is a device that measures and outputs the azimuth angle of a moving body. The absolute azimuth measuring means  1302  can be embodied, for example, by an electronic compass (combination of a magnetic sensor and an acceleration sensor). The preprocessing section  1603  receives movement speed measurement information  1611  and integrates it to calculate a travel distance. If the travel distance thus calculated is greater than or equal to a predetermined threshold value, the preprocessing section  1603  outputs absolute azimuth information  1310  as a preprocessing signal  1612 . Further, if the absolute azimuth information  1310  has been given information on uncertainty, the preprocessing section  1603  outputs absolute azimuth information  1310  with the least uncertainty. If the travel distance thus calculated is not greater than the predetermined threshold value, the preprocessing section  1603  does not output any absolute azimuth information  1310 . The absolute azimuth measurement result integrating means  1304  receives measurement results from a plurality of absolute azimuth measuring means, integrates the measurement results into one final absolute azimuth estimate result, and outputs the final absolute azimuth estimate result as an integrated signal  1313 . The absolute azimuth measurement result integrating means  1304  is the same device as that described with reference to  FIG. 7 . 
       FIG. 12  is a flow chart showing the content of data processing in the preprocessing section  1603 . An explanation is given with reference to  FIG. 12 . When the process is started, first, in Step S 1801 , the preprocessing section  1603  receives movement speed measurement information  1611  on a moving body from the movement speed measuring means  1601  and receives absolute azimuth information  1310  from the absolute azimuth measuring means  1302 . Next, in Step S 1802 , the preprocessing section  1603  time-integrates movement speeds as movement speed measurement information  1611  to calculate a travel distance. Next, in Step S 1803 , the preprocessing section  1603  determines whether or not the travel distance thus calculated is greater than a predetermined threshold value. If the travel distance is greater than the predetermined threshold value, the preprocessing section  1603  proceeds to Step S 1804 . Alternatively, if the travel distance is less than or equal to the predetermined threshold value, the preprocessing section  1603  proceeds to Step S 1805 . In Step S 1804 , the preprocessing section  1603  outputs received absolute azimuth information  1310  as a preprocessing signal  1612 . At the same time, the preprocessing section  1603  resets to zero the distance that is used in calculating the travel distance. In Step S 1805 , the preprocessing section  1603  does not output any absolute azimuth information and notifies the absence of output. 
       FIG. 13  is a block diagram of a configuration of another moving body positioning apparatus according to the present invention. In  FIG. 13 , reference numerals  1902 ,  1904 ,  1901 , and  1903  indicate absolute azimuth measuring means, absolute azimuth measurement result integrating means, travel distance measuring means, and a preprocessing section, respectively. Reference numerals  1910 ,  1911 ,  1912 , and  1913  indicate absolute azimuth information, travel distance information, a preprocessing signal outputted by the preprocessing section, and an integrated signal of positioning results, respectively. 
     In the block diagram of  FIG. 13 , the moving body positioning apparatus includes travel distance measuring means  901  for measuring a travel distance that a moving body has traveled, instead of including movement detecting means. The travel distance measuring means  901  used here is measuring means for measuring and outputting a relative travel distance, and is identical to the travel distance measuring means  901  described with reference to  FIG. 3 . 
     The absolute azimuth measuring means  1902  is a device that measures the absolute azimuth of a moving body, and is identical to the absolute azimuth measuring means  1302  shown in  FIG. 9 . The preprocessing section  1903  receives a relative travel distance as travel distance information  1911  from the travel distance measuring means  1901  and receives absolute azimuth information  1910  from the absolute azimuth measuring means  1902 . When the distance from the reference position exceeds a predetermined threshold value, the preprocessing section  1903  outputs absolute azimuth information  1910  as a preprocessing signal  1912 . The absolute azimuth measurement result integrating means  1904  is identical to the absolute azimuth measurement result integrating means  1304  described with reference to  FIG. 9 . The absolute azimuth measurement result integrating means  1904  receives input from a plurality of absolute azimuth measuring means and outputs a final absolute azimuth estimate result as an integrated signal  1913  in accordance with its internal state and the input. 
       FIG. 14  is a flow chart showing the content of data processing in the preprocessing section  1903 . An explanation is given with reference to  FIG. 14 . When the process is started, first, in Step S 2001 , the preprocessing section  1903  receives travel distance information  1911  from the travel distance measuring means  1901  and receives absolute azimuth information  1910  from the absolute azimuth measuring means  1902 . Next, in Step S 2002 , the preprocessing section  1903  accumulates relative travel distances as travel distance information  1911  to calculate a travel distance from a reference position, i.e., a travel distance from a position at which the last absolute azimuth information  1910  was outputted. In Step S 2003 , the preprocessing section  1903  determines whether or not the travel distance thus calculated is greater than a predetermined threshold value. If the travel distance is greater than the predetermined threshold value, the preprocessing section  1903  executes Step S 2004 . If the travel distance is not greater than the predetermined threshold value, the preprocessing section  1903  executes Step S 2005 . In Step S 2004 , the preprocessing section  1903  outputs received absolute azimuth information  1310  as a preprocessing signal  1612 . At the same time, the preprocessing section  1903  resets the reference position in Step S 2002  to zero. In Step S 2005 , the preprocessing section  1903  does not output any absolute azimuth information and notifies the absence of output. 
     REFERENCE SIGNS LIST 
       102  Position measuring means 
       104  Positioning result integrating means 
       110  Position information 
       113  Integrated signal of positioning results 
       701  Movement detecting means 
       703  Preprocessing section 
       711  Movement detection signal 
       712  Preprocessing signal 
       713  Integrated signal of positioning results 
       801  Movement speed measuring means 
       803  Preprocessing section 
       811  Movement speed information 
       812  Preprocessing signal 
       901  Travel distance measuring means 
       903  Preprocessing section 
       911  Travel distance information 
       1301  Movement detecting means 
       1302  Absolute azimuth measuring means 
       1303  Preprocessing section 
       1304  Absolute azimuth positioning result integrating means 
       1310  Absolute azimuth information 
       1311  Movement detection signal 
       1312  Preprocessing signal 
       1313  Integrated signal of positioning results 
       1504  Positioning result integrating means 
       1601  Movement speed measuring means 
       1602  Absolute azimuth measuring means 
       1603  Preprocessing section 
       1611  Movement speed measurement information 
       1612  Preprocessing signal from preprocessing section 
       1701  Walking speed measuring means 
       1901  Travel distance measuring means 
       1902  Absolute azimuth measuring means 
       1903  Pro-processing section 
       1904  Absolute azimuth positioning result integrating means 
       1910  Absolute azimuth information 
       1911  Travel distance information 
       1912  Preprocessing signal 
       1913  Integrated signal of positioning results