JP4841990B2 - RFID reader and control method - Google Patents

Description

The present invention relates to an RFID reader and a control method for reading an RFID (Radio Frequency Identification) data carrier (also simply referred to as RFID).

  In recent years, RFID systems that provide identification of objects and other services by attaching RFID to objects and obtaining the required information by reading the RFID have been put to practical use. One such service is the location of RFID. A navigation service that provides a service corresponding to position information by storing information in the RFID itself or a server, and acquiring position information by reading the RFID has been proposed (for example, see Patent Document 1).

  As a specific example of such a navigation service using RFID, for example, an RFID reader that reads RFID is connected to a network and installed at a specific location, and a portable communication terminal associated with the RFID read by this RFID reader is used. Thus, a service is conceived in which information associated with the installation location of the RFID reader is transmitted by mail to provide the information at the location to the user who owns the RFID.

  Conversely, the RFID is embedded in a Braille block, etc., and the RFID is read by, for example, an RFID reader mounted on a cane for a blind person, and a specific server is inquired about an information providing destination corresponding to the read RFID, and the information is provided. Obtain information according to the location where the RFID is embedded and send it to the portable communication terminal associated with the RFID reader to provide the acquired information as a voice to the blind person using the cane A service is also considered.

  On the other hand, in recent notebook PCs and PDAs, it is possible to access the Internet by inserting a wireless communication card for PHS, cellular phone, wireless LAN or the like. In addition, mobile phones are becoming more sophisticated, and it is possible to acquire various types of information as well as e-mails with a single mobile phone, and set a destination for mobile phones equipped with GPS. Thus, there is also a service that provides a travel route to the destination.

Since these portable information terminals can be connected to the Internet, various information can be acquired at various places.
JP 2004-206590 A

  However, in a navigation service using RFID, when RFID is read by an RFID reader connected to a network, and information related to the installation location of the RFID reader is sent to a mobile communication terminal associated with the read RFID by e-mail. Has the advantage that it can provide information without depending on the user's terminal operation, but on the other hand, after the RFID reader reads the RFID attached to the user, the user can view the contents of the associated mail. Until it becomes possible, it takes a very long time due to the communication between the RFID reader and the mail server of the portable communication terminal, the intermittent reception interval in the portable communication terminal, etc., and the user has moved to another place during that time. If this happens, the timeliness of the information will be lost.

  Also, when the RFID is read by the RFID reader and information corresponding to the installation location of the RFID is obtained from the corresponding information providing destination, the amount of information is large because the wireless communication band of the mobile communication terminal is not so large. Will take time to download. For this reason, if the user moves to another place during that time, the timeliness of the information will be lost as well.

  On the other hand, when trying to acquire some information with a portable information terminal such as a notebook PC or PDA or a mobile phone, the user takes out the terminal, connects to the network, and searches for a site having the target information. , Finding the site you want is very difficult, and in fact, you don't get the information right when you want it. Rather, even if it takes time to search for a site having the target information, the necessary information is often not obtained.

  As a method of solving the above problems at once, the portable information terminal is equipped with an RFID reader function to automatically read the RFID present in the surroundings, and the portable information terminal owner based on the RFID reading order, etc. A navigation service that provides information immediately when the owner operates the portable information terminal by prefetching information that is presumed to be necessary and predicting the behavior of the mobile information terminal.

  By the way, in this case, in order to accurately infer the behavior of the owner, it is necessary to read more RFIDs and acquire information. For this purpose, the RFID information acquisition operation is not performed, that is, the RFID reader function. Therefore, it is necessary to frequently perform an automatic operation for acquiring RFID information in a short cycle (so-called intermittent operation).

  However, in order to read the RFID, for example, when the RFID is a passive type in which a battery is not incorporated, as shown in the timing chart of FIG. 12, the RFID is driven during the period T1, T2, T3 sequentially from the RFID reading means. In the period T2, a command signal for transmitting identification information and the like is radiated from the RFID, and in the period T3, the power supply signal is radiated again. In the period T3, the signal is radiated from the RFID side. The transmission signal including the identification signal is received and information from the RFID is acquired.

  For this reason, if the information acquisition operation of RFID is frequently performed, a series of operations in the periods T1 to T3 shown in FIG. 12 are repeatedly executed with a short sleep time, and a power supply signal for reading the RFID There is a concern that the number of times the command signal is emitted increases, and as a result, the power consumption increases and the battery usage period of the portable information terminal is shortened.

  Note that such a power consumption problem is not limited to passive RFID, but also occurs when reading a semi-passive RFID because a command signal needs to be emitted from the RFID reader. In addition, when reading an active RFID, it is necessary to shorten the sleep time and frequently set the reception state in order to receive a transmission signal from the RFID, so that power consumption also increases.

Accordingly, an object of the present invention made in view of such circumstances is to provide an RFID reader and a control method capable of efficiently reading an RFID while effectively reducing power consumption.

The invention of the RFID reader according to claim 1 that achieves the above object is as follows:
Position information acquisition means for acquiring position information;
RFID information acquisition means for performing an information acquisition operation on RFID;
Storage means for correspondingly storing position information and RFID information acquisition result when the RFID information acquisition means executes an information acquisition operation;
Based on the position information and RFID information acquisition result stored in the storage means and the current position information acquired by the position information acquisition means, other than the position information not acquired RFID information stored in the storage means An acquisition operation control means for determining a sleep time so as to execute an information acquisition operation at the position of the information processing apparatus , and controlling activation of the RFID information acquisition means based on the determined sleep time ;
It is characterized by having.

Furthermore, the invention of the control method of the RFID reader according to claim 2 for achieving the above object is as follows:
Obtaining location information;
Performing an information acquisition operation on the RFID;
Storing correspondingly the position information and RFID information acquisition result when the information acquisition operation is executed;
Based on the stored position information and the RFID information acquisition result and the acquired current position information, the sleep time is determined so as to execute the information acquisition operation at a position other than the stored position information where the RFID information is not acquired. And controlling the activation of information acquisition for the RFID based on the determined sleep time;
It is characterized by having.

  According to the present invention, the location information when the RFID information acquisition unit executes the information acquisition operation and the RFID information acquisition result are stored in the storage unit in association with each other, and there is no RFID at the position where the RFID information could not be acquired. Since the RFID information acquisition means is not activated thereafter as the position, it is possible to read the RFID efficiently while effectively reducing power consumption.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a portable information terminal as an RFID reader according to an embodiment of the present invention.

  In the present embodiment, an RFID reader function is mounted on a notebook PC, PDA, mobile phone, or the like, the RFID existing around is read, and the behavior of the owner of the portable information terminal 1 is determined based on the reading order of the RFID. The information presumed to be necessary is predicted in advance, and when the owner operates the portable information terminal 1, the information presumed to be the best can be provided immediately.

  For this reason, this portable information terminal 1 includes an RFID reading means 2 that is an RFID reader function, a position information acquiring means 3 having a GPS receiver for acquiring current position information, a time measuring means 4 for generating time information, an RFID reading RFID information acquisition means 5, RFID information storage means 6, RFID information storage means 6, behavior estimation means 7 serving as prediction means, personal action storage means 8, information selection means 9, search information storage means 10. Output means 11 comprising a display, a speaker, etc., RFID intermittent acquisition operation control means which is an acquisition operation control means for controlling activation of the RFID information acquisition means 5 so as to intermittently execute an RFID information acquisition operation, that is, a step time. 12. Effectiveness calculating means 13 for calculating the effectiveness indicating the degree of necessity of searching for RFID, performing wireless communication A wireless communication means 14 including an antenna, and a power supply circuit 15 including a battery for supplying necessary power to each unit, are connected to the network 22 via wireless communication between the wireless communication means 14 and the base station 21. It has become so.

  Here, the RFID information storage means 6 and the personal action storage means 8 constitute storage means for correspondingly storing the position information, time information, and RFID information acquisition result when the RFID information acquisition means 5 executes the information acquisition operation. is doing. The wireless communication unit 14 transmits necessary information including the identification information acquired by the RFID information acquiring unit 5 to the base station 21 and transmits the required information from the behavior estimating unit 7 and the information selecting unit 9 to the base station. 21 and a function of receiving information transmitted from the base station 21 and outputting the received information to the RFID information acquisition means 5, the behavior estimation means 7, and the information selection means 9 according to the contents. ing.

  In FIG. 1, as RFID, RFID 32A attached to the time display board 31A installed at the bus stop A, RFID 32B attached to the time display board 31B installed at the bus stop B, and the bag 33 are attached. RFID 32C. Here, the identification information of RFID 32A is ID = A, the identification information of RFID 32B is ID = B, and the identification information of RFID 32C is ID = C.

  The network 22 is connected to an RFID storage destination resolution server 23 and Web sites 24A to 24C corresponding to the RFIDs 32A to 32C.

  In FIG. 1, RFIDs 32 </ b> A to 32 </ b> C existing around the movement route of the portable information terminal 1 are read by the RFID reading unit 2 as the portable information terminal 1 approaches, and the identification information is sent to the RFID information acquisition unit 5. To be acquired.

  The RFID information acquisition unit 5 transmits the acquired identification information to the RFID storage destination resolution server 23 on the network 22 via the wireless communication unit 14 and the base station 21, and stores the information related to the read RFID (for example, URL ), And the obtained accumulation destination and the read RFID identification information (ID) are associated with each other and stored in the RFID information storage means 6.

  Further, the RFID information acquisition means 5 acquires the position information and time information at the time when the RFID information acquisition operation is performed from the position information acquisition means 3 and the timing means 4, respectively. When the identification information is acquired from the RFID, these position information and time information are stored in the RFID information storage unit 6 in association with the identification information, and are output to the behavior estimation unit 7 together with the acquired identification information. On the other hand, when the identification information is not acquired from the RFID by the information acquisition operation of the RFID, the position information and time information at that time are stored in the RFID information storage unit 6 together with the read result.

  The behavior estimation unit 7 sequentially stores the RFID identification information, the position information, and the time information from the RFID information acquisition unit 5 in the personal behavior storage unit 8. Further, the behavior estimation unit 7 determines whether or not the owner of the portable information terminal 1 passes for the first time based on the currently acquired identification information and the identification information already stored in the personal behavior storage unit 8. Then, the determination result is output to the RFID intermittent acquisition operation control means 12 via the RFID information acquisition means 5, and if it is determined that the place has already passed, the movement direction is also predicted and read next. The RFID identification information and position information are output to the information selection unit 9 and also output to the RFID intermittent acquisition operation control unit 12 via the RFID information acquisition unit 5.

  Based on the RFID identification information that is the estimation result from the behavior estimation means 7, the information selection means 9 is wireless from the accumulation destination on the network 22 related to the RFID identification information stored in the RFID information storage means 6. New information is prefetched and stored in the search information storage means 10 via the communication means 14, and when the owner performs some terminal operation (for example, pressing a predetermined key (not shown)), the current position information and Based on the position information of the already acquired RFID, the RFID that is estimated to be the best is estimated from the estimated and acquired RFID, and the pre-read information related to the specified RFID is read from the search information storage means 10 , Output to the output means 11.

  On the other hand, when the RFID intermittent acquisition operation control unit 12 determines that the place where the behavior estimation unit 7 passes for the first time, the RFID information acquisition unit 12 acquires RFID information according to the acquisition degree of the RFID identification information stored in the RFID information storage unit 6. A distance for executing the operation is calculated, and a sleep time for pausing the RFID information acquisition operation is set according to the calculated distance to control the intermittent acquisition operation of the RFID information acquisition means 5.

  On the other hand, if it is determined that the action estimation unit 7 has already passed, the route is based on the current position information and the RFID position information that will be read next from the action estimation unit 7. The number of readings at this time is calculated, and an instruction for calculating the effectiveness is given to the effectiveness calculation means 13, whereby the position information and time stored in the RFID information storage means 6 in the effectiveness calculation means 13 are given. Based on the information, it is possible to calculate the effectiveness indicating the degree of necessity of searching for the RFID for each location in the section where information from the RFID could not be acquired despite the information acquisition operation. The intermittent acquisition operation is controlled by setting the sleep time of the RFID information acquisition means 5 so that the information acquisition operation is preferentially executed for the places corresponding to the number of times of high reading.

  Note that the RFID intermittent acquisition operation control means 12 is configured so that the current position information acquired from the position information acquisition means 3 matches the position information of the RFID information already acquired stored in the RFID information storage means 6. When the elapsed time from the acquisition time of RFID information to the present time is less than the predetermined time, the RFID information acquisition means 5 is not activated as the RFID information has not changed, and the RFID information changes when the predetermined time has elapsed. The RFID information acquisition means 5 is activated as a possibility of being there.

  Hereinafter, the RFID information acquisition operation by the portable information terminal 1 according to the present embodiment will be described in more detail with reference to the flowcharts shown in FIGS. 2 mainly shows the operation in the first pass route, and FIG. 3 mainly shows the operation in the already passed route.

  First, in synchronization with the activation of the RFID search mode, the intermittent acquisition operation setting process of the RFID information acquisition means 5 is executed to set the default value of the sleep time (Ts) (step S1). Thereafter, the sleep time is set (step S2), the sleep is executed (step S3), the sleep time is expired (step S4), the sleep is canceled (step S5), and the RFID information acquisition means 5 reads the RFID. The means 2 is driven to execute an RFID information acquisition operation (step S6). When the search mode is activated, the sleep time (Ts) is set to a default value in step S2.

  When the information acquisition operation is executed, the position information and time information at that time are acquired from the position information acquisition means 3 and the timing means 4 respectively (steps S7 and S8). In the second and subsequent information acquisition operations, further sequential information is obtained. Was the movement speed (Vw) estimated based on the movement distance and movement time obtained from the position information and time information in the acquisition operation (step S9), and the RFID information acquisition means 5 was able to acquire the RFID identification information (ID)? It is determined whether or not the transmission signal from the RFID can be received without error in the RFID reading means 2 (step S10).

  Here, when the RFID ID can be acquired, it is determined whether the ID is stored in the RFID information storage means 6 and the personal action storage means 8, that is, whether the acquired ID has already been received. (Step S11) If it is acquired for the first time, the acquired ID, position information, and time information are associated with each other and stored in the RFID information storage means 6 and the personal action storage means 8 assuming that the place is the first place to pass ( Step S12) and the process proceeds to step S6.

  In contrast, if the RFID ID could not be acquired in step S10, the result is stored in the RFID information storage means 6 together with the position information and time information acquired in steps S7 and S8 (step S13). The unacquired elapsed distance (Lw) is calculated (step S14), the sleep distance (Ls) is calculated based on the Lw (step S15), and the sleep time Ts is calculated based on the movement speed Vw of the Ls and Lw. If calculated (step S16) and the search mode has not ended (step S17), the process proceeds to step S2, the sleep time Ts is set to Ts calculated in step S16, and the above operation is repeated.

  As the sleep distance Ls in step S15, for example, as shown in FIG. 4, a first threshold value (Lw1) and a second threshold value (Lw2, where Lw2> Lw1) for the unacquired elapsed distance Lw are set, and Lw < For Lw1, Ls = Ls1, Lw> Lw2, Ls = Ls2 (where Ls1 <Ls2), and Lw1 ≦ Lw ≦ Lw2, Ls = αLw (α is a constant).

  For example, as shown in FIG. 5, the sleep time Ts in step S16 sets a threshold value (Vth) for the moving speed Vw, Ts = Tc (a constant value) when Vw <Vth, and Ts = Vc when Vw ≧ Vth. Calculated by Ls / Vw.

  On the other hand, if it is determined in step S11 that the ID acquired in step S10 has already been received, the route estimation process shown in FIG. 3 is executed assuming that the ID has already been passed (step S18), Based on the information stored in the personal action storage unit 8, an RFID that is estimated to be read next from the currently acquired ID is set as a target ID (step S19), and from the currently read RFID to the target RFID Distance (L) is calculated (step S20), and the current number of readings (N) is calculated based on the distance L and the like (step S21). The details of the process for calculating the number of readings N will be described later.

  Thereafter, N search target points (Lnxt) corresponding to the number of reading times are set (step S22), and based on the distance to the next search target point Lnxt closest to the current position and the latest movement speed Vw estimation result, Similarly to step S16, the sleep time Ts is calculated (step S23).

  The search target point Lnxt in step S22 is searched by the effectiveness calculation means 13 based on, for example, the past search degree (Ap) at the place (P) (for example, the elapsed time from the past search time). In step S21, the effectiveness (Lp) indicating the degree of necessity is calculated, and as a candidate for the next search for the place P having the highest effectiveness Lp from the places having the low search degree Ap in the distance L. Set sequentially for the calculated number of readings. Details of the search target score (Lnxt) setting process will be described later.

  After calculating the sleep time Ts to the next search target point Lnxt in step S23, if the search mode has not ended (step S24), the calculated sleep time Ts is set as in steps S2 to S10 (step S25), the sleep is executed (step S26), the sleep time is expired (step S27), the sleep is canceled (step S28), the RFID information acquisition operation is executed (step S29), and the position information at that time And time information is acquired (steps S30 and S31), the moving speed (Vw) is estimated based on the position information and time information in the sequential information acquisition operation (step S32), and the transmission signal from the RFID is received without error. It is determined whether or not it has been completed (step S33).

  Here, if the RFID can be received, the process proceeds to step S11 in FIG. 2, and if the RFID cannot be received, the position information obtained in steps S30 and S31 and the result obtained in steps S30 and S31, as in step S13. The time information is stored in the RFID information storage means 6 (step S34).

  Thereafter, a path error is calculated based on the position information of the search target point Lnxt set in step S22 and the position information at the time of execution of the current information acquisition operation acquired in step 30 (step S35). It is determined whether or not a preset threshold is exceeded (step S36). If the threshold is exceeded, it is determined that another route, that is, a new route is moving (step S37), and the normal intermittent acquisition operation mode is set (step S38). ) Go to step S1 and repeat the above operation.

  On the other hand, if the path error is less than or equal to the threshold value, it is determined whether or not the current information acquisition operation position has passed the position of the target ID (step S39), and if it has passed, the process proceeds to step S18. The route estimation process is executed, and if it has not passed, the distance from the current information acquisition operation execution position to the next search target point Lnxt is calculated again, and based on the latest movement speed Vw estimated in step S32. In step S23, the sleep time Ts is calculated in the same manner.

  6 and 7 are schematic diagrams for explaining the intermittent acquisition operation in the present embodiment.

  In FIG. 6, it is assumed that the RFID is detected at the place P10 and the place P17 when the first route is passed. In the section of the distance L between the place P10 and the place P17, in this case, a total of six searches (information acquisition operations) are performed at the places P11 to P16, but all of these places P11 to P16 are RFIDs. Is not detected.

  In FIG. 6 and FIG. 7, since the RFID is not acquired at the place P11, a longer sleep time than before is set according to the unacquired elapsed distance from the immediately preceding place P10 (FIG. 2). In steps S14 to S16), the search is executed at the place P12. Similarly, since the RFID is not acquired at the place P12, the sleep time longer than that at the time of executing the search at the place P11 is set according to the unacquired elapsed distance from the immediately preceding place P11, and the search at the place P13 is performed. After that, the search is executed with the same sleep time.

  When the RFID is detected at the place P10 as the second time, the place P10 and the place P17 where the RFID is detected next are detected by the route estimation process and the target ID setting process (steps S18 and S19 in FIG. 3). The route is estimated, and further, the distance calculation process and the reading count calculation process (steps S20 and S21 in FIG. 3) are not searched by the previous time at the location corresponding to the current reading count and the reading count on the path. In this case, two places P21 and P22 are calculated as highly effective places, and an information acquisition operation is performed at these places P21 and P22.

  Further, in the third search, similarly, the places P31 and P32 that are not searched by the previous time and are likely to be searched this time are calculated as highly effective places, and information is obtained from these places P31 and P32. An acquisition operation is performed.

  As shown in FIG. 7, the route passing through the place P10 and the place P17 is estimated, and is calculated corresponding to the place P21 of the search target point Lnxt set as the second search and the set place P21. When the path error with the place P51 where the information acquisition operation is actually executed exceeds the threshold due to the expiration of the sleep time, it is determined that the new path is moving, and thereafter, the sleep time is set as an initial value, for example, as a default value. A normal intermittent acquisition operation, which is a search, is executed.

  Next, with reference to FIGS. 8A and 8B, the calculation process of the number of readings (number of activations) executed in step S21 of FIG. 3 will be described.

  As shown in FIG. 8A, when the information acquisition operation time for one RFID is Tread [s] and the sleep time is Tsleep [s], the time of one cycle of information acquisition operation (Tcycle [s]) is It is calculated by the following equation (1). If the estimated moving speed is Vest [m / s], the moving distance (Lcycle [m]) of one cycle is calculated by the following equation (2).

Tcycle = Tsleep + Tread (1)
Lcycle = Tcycle × Vest (2)

  Therefore, as shown in FIG. 8B, when the distance of the target section [Pstt, Pend] is Larea [m], the number of times that can be read (Nest [times]) in one pass is (3) ), And this value is the maximum number of activations of the RFID information acquisition means 5 during the sleep time (Tsleep [s]). Note that Pstt, Pend, and Larea in FIG. 8B correspond to the place P10, the place P17, and the distance L in FIG.

Nest = Larea / Lcycle (3)

  However, since the RFID reading means 2 has a RFID readable distance, if the RFID readable distance is Lread [m], the ideal number of readings (Nideal [times]) is (4) ).

Nideal = Larea / (Lread / n) (4)
However, n ≧ 1

  Also, if this ideal number of readings (Nideal [times]) is to be executed at a constant update cycle (for example, Dperiod [days]), the number of readings required to read in one day (Nday [times / day]) Is given by the following equation (5).

Nday = Nideal / Dperiod (5)

  However, since it does not always pass through the same section [Pstt, Pend] every day, the cycle (average passage interval) that actually passes is (Dpass [day]) with respect to the update cycle (Dperiod [day]). Then, the number of readings (Npass [times]) in one pass is given by the following equation (6).

Npass = Nday × Dpass (6)

  In the present embodiment, the above calculation is executed in step S21 in FIG. 3, and Npass of equation (6) is finally calculated as the number of readings (N). Note that the estimated moving speed (Vest [m / s]) is a reading time (Tread [s]) calculated by the RFID readable distance (Lread [m]) and one RFID information acquisition operation time (Tread [s]). If it is greater than Vread [m / s]), it is determined that reading is impossible and no information acquisition operation is performed.

  FIG. 9 is a graph for explaining a specific example of the number of activations (number of readings) with respect to the passage interval in the present embodiment.

  Here, the sleep time (Tsleep) is 5 [s], the RFID information acquisition operation time (Tread) is 0.2 [s], the estimated moving speed (Vest) is 3 [Km / h], and the section distance (Larea) is 30 [m], RFID readable distance (Lread) is 4 [m], and update period (Dperiod) is 30 [day]. In order to improve the reading accuracy of RFID, n in the above equation (4) is set to n = 2, and the substantial reading distance (Lread / n) of RFID is set to 2 [m].

  In FIG. 9, the thick solid line indicates the number of possible readings (Nest) in one pass. In this case, Tcycle = Tsleep + Tread = 5 + 0.2 = 5.2 [s], so that Nest = Larea / Lcycle = Larea / (Tcycle × Vest) = 30 / (5.2 × 3000/3600) ≈6.9. A thick broken line indicates the number of activations (Npass) with respect to the passage interval (Dpass).

  As is clear from FIG. 9, according to the present embodiment, the shorter the passage interval (<14 days), the fewer the number of activations that can be activated at the time of one pass, and the power consumption associated with the RFID search can be reduced. It becomes possible to reduce.

  FIG. 10 is a graph for explaining a specific method for determining the number of activations (number of readings) under the same conditions as in FIG.

  Here, when passing through the same section, the number of times of passage in the past week (including the current time) in that section is calculated, and the number of times of activation corresponding to the number of times of passage is acquired based on FIG. For example, if the number of passages in the past week is 2 times, passing 2 times within 1 week (7 days) means that the passage interval is 3.5 days (= 7 [days] / 2 [times]) Therefore, since the number of activations in this case is 1.75 from FIG. 9, it may be rounded up to 2 times.

  In addition, when the number of passages in the past week is 4 [times], 4 passages in one week (7 days) means that the passage interval is 2 days (= 7 [days] / 4 [times] ( In this case, the number of activations is one from FIG.

  Thus, by estimating the passage interval in a period shorter than the longest acquisition cycle period, and setting the number of activations based on the estimated passage interval, even in a short period, The number of activations can be reduced, and the power consumption accompanying the RFID search can be reduced.

  FIG. 11 is a graph showing a comparison of the cumulative number of activations according to the present embodiment and the cumulative number of activations by the conventional apparatus on the same route.

  In FIG. 11, the solid line indicates the cumulative number of activations according to the present embodiment, and the broken line indicates the cumulative number of activations by the conventional apparatus that accumulates the readable number of times (Nest) in one pass. The conditions are the same as in FIG. 9, and both pass once a day.

  As is clear from FIG. 11, when the number of possible readings (Nest) in one pass is executed each time as in the prior art, the cumulative number of activations in 30 days is 207 (6.9 [times] × 30 [days] ]) [Times]. In contrast, according to the present embodiment, the cumulative number of activations in 30 days is 15 (0.5 [times] × 30 [days]) [times], and the cumulative number of activations is far reduced compared to the conventional case. Can save energy.

  Next, an example of the search target score (Lnxt) setting process in step S22 of FIG. 3 will be described with reference to FIG.

  In the search target point setting process, first, the section of the places P10 to P17 is divided by, for example, the number of times of reading (Nest) or the ideal number of readings (Nideal) in one pass, and each of the places (P ), The degree of separation Wp from the already searched place is calculated by the following equation (7).

  In the above equation (7), k is a weighting coefficient in the place before and after each place P. For example, k is set as a quadratic function that becomes minimum at the place P and increases as the distance from the place P increases. Ap is the search degree at the place P and indicates the elapsed time from the already searched time. This elapsed time is defined as the time read at the place P20 with the time at each place (P) of this time uniformly, and the elapsed time from the already searched place at the place that matches the already searched place, and the place that does not match the already searched place. Then, let elapsed time be zero. The search degree addition range (± I) is preferably set so as to include at least one already searched place.

  Accordingly, the separation degree Wp calculated by the above equation (7) increases as the distance from the already searched place increases, and the distance from the place S10 increases because the elapsed time from this time becomes longer.

  Therefore, the effectiveness (Lp) indicating the degree of necessity of searching is set to, for example, Lp = Wp, and the effectiveness Lp is the largest in the distance L from the place where the past search degree Ap is low, that is, the unsearched place. The place P is set as a target point candidate to be searched next. Further, when the number of times of reading (N) calculated in step S21 is plural, including the already set next search target point, similarly, the highest effectiveness Lp is found from the place where the past search degree Ap is low. The process of setting the place P as a candidate for a target point to be searched next is repeated to set N search target points.

  Accordingly, in the case of FIG. 6, in the second search, first, the first search target is the intermediate place P21 between the places P12 and P13 near the place P10 where the sequential search places are separated in the first search. Next, by setting the location P21, the location P22 in the middle of the locations P14 and P15 near the location P21 is set as the second search target score. Two places, a place P31 in the middle of the places P13 and P14 that are sequentially separated in the second search and a place P32 in the middle of the places P15 and P16, are set as the search target scores.

  As described above, in this embodiment, when it is determined that the place has already passed, unlike the normal intermittent acquisition operation, the search is not performed at the place where the search (reading) has already been performed. In addition to searching at unsearched places where the passage of time is large and not searching all places at once, the number of searches is controlled according to the user's usage on the route, so carelessly Therefore, it is possible to extend the use period of the battery of the power supply circuit 15 without consuming electric power, and it is possible to efficiently accumulate important information.

  It should be noted that the present invention is not limited to the above embodiment, and many changes or modifications are possible. For example, when searching for the same route, in the above-described embodiment, the degree of separation Wp that increases as the distance from the already searched place is calculated according to Equation (7), and the effectiveness (Lp) is set to Lp = Wp. Among them, the place P having a large effectiveness Lp is set as a candidate to be searched next. However, the search degree Ap such as the elapsed time, the weighting function, etc. are appropriately set and become smaller as the distance from the searched place becomes smaller. The search point proximity can be calculated, and the reciprocal thereof can be set as the effectiveness Lp. Similarly, among the unsearched locations, the place P with the highest effectiveness Lp can be set as a target point candidate to be searched next.

  In calculating the search target point, when the search degree Ap is calculated as the elapsed time from the already searched time point, the latest estimated moving speed is not set in place of the time at each location where the distance L is divided. Also, the scheduled search time can be calculated for each location based on the distance to each location, and the elapsed time from the already searched time can also be calculated.

  Furthermore, the present invention is not limited to reading passive RFID, but can be effectively applied to reading semi-passive or active RFID. In these cases, power is consumed carelessly. It is possible to efficiently accumulate important information without having to do so.

It is a block diagram which shows schematic structure of the portable information terminal as an RFID reader which concerns on one embodiment of this invention. 2 is a flowchart showing an RFID information acquisition operation mainly in the first-pass route by the portable information terminal shown in FIG. Similarly, it is a flowchart showing an RFID information acquisition operation mainly in the already passed route. Similarly, it is a figure which shows the example of calculation of the sleep distance with respect to the unacquired elapsed distance. Similarly, it is a figure which shows the example of calculation of the sleep time with respect to a moving speed. Similarly, it is a schematic diagram explaining an intermittent acquisition operation. Similarly, it is a schematic diagram explaining an intermittent acquisition operation. It is a figure for demonstrating the calculation process of the frequency | count of reading (starting frequency) performed by step S21 of FIG. 6 is a graph for explaining a specific example of the number of activations (number of readings) with respect to a route passage interval by the portable information terminal shown in FIG. 10 is a graph for explaining a specific method of determining the number of activations (number of readings) under the same conditions as in FIG. 9. It is a graph which compares and shows the cumulative starting frequency | count of RFID information acquisition by the portable information terminal shown in FIG. 1 in the same path | route, and the cumulative starting frequency | count by a conventional apparatus. FIG. 10 is a timing diagram illustrating a passive RFID reading operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Portable information terminal 2 RFID reading means 3 Position information acquisition means 4 Timekeeping means 5 RFID information acquisition means 6 RFID information storage means 7 Behavior estimation means 8 Personal action storage means 9 Information selection means 10 Search information storage means 11 Output means 12 RFID intermittent Acquisition operation control means 13 Effectiveness calculation means 14 Wireless communication means 15 Power supply circuit 21 Base station 22 Network 23 RFID storage destination resolution server 24A-24C Web site 31A, 31B Time display board 32A-32C RFID
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Claims (2)

Position information acquisition means for acquiring position information;
RFID information acquisition means for performing an information acquisition operation on RFID;
Storage means for correspondingly storing position information and RFID information acquisition result when the RFID information acquisition means executes an information acquisition operation;
Based on the position information and RFID information acquisition result stored in the storage means and the current position information acquired by the position information acquisition means, other than the position information not acquired RFID information stored in the storage means An acquisition operation control means for determining a sleep time so as to execute an information acquisition operation at the position of the information processing apparatus , and controlling activation of the RFID information acquisition means based on the determined sleep time ;
An RFID reader characterized by comprising: Obtaining location information;
Performing an information acquisition operation on the RFID;
Storing correspondingly the position information and RFID information acquisition result when the information acquisition operation is executed;
Based on the stored position information and the RFID information acquisition result and the acquired current position information, the sleep time is determined so as to execute the information acquisition operation at a position other than the stored position information where the RFID information is not acquired. And controlling the activation of information acquisition for the RFID based on the determined sleep time;
A method for controlling an RFID reader, comprising:

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