Information processing device, positioning method, and storage medium

Abstract

The present invention provides an information processing device, a positioning method, and a storage medium. Even when the validity period of a predicted ephemeris has expired during positioning, positioning of an object is continued. A determination unit (173) determines whether the remaining time until the validity period of the predicted ephemeris, i.e., the predicted data obtained by predicting the orbital information of a GPS satellite, is less than or equal to a determination time set to a time equal to or greater than the maximum time the object is assumed to be in a certain state. When the positioning unit (174) determines that the remaining time until the validity period of the predicted ephemeris is less than or equal to the determination time, the positioning unit (174) executes an acquisition operation of the actual orbital information data of the GPS satellite, i.e., the actual ephemeris, based on the GPS signal received by the GPS receiving unit (120), and positions the object based on the actual ephemeris acquired by executing the acquisition operation.

Description

Technical Field

[0001] The present invention relates to an information processing device, a positioning method and a storage medium. Background Art

[0002] To perform positioning using a GPS (Global Positioning System) receiver, it is necessary to demodulate the GPS signals transmitted from GPS satellites and obtain the ephemeris (hereinafter referred to as the "actual ephemeris"), which is the actual orbital information data of the GPS satellites. Acquiring the actual ephemeris takes time, so positioning requires approximately several minutes from the time the GPS receiver is activated. Furthermore, the actual ephemeris has an expiration date of approximately four hours, so if the expiration date has expired since the actual ephemeris was acquired, the GPS receiver must obtain the actual ephemeris again.

[0003] As a technology that can shorten the time required for positioning and extend the validity period of the ephemeris, there is a known technique that uses a long-term prediction of the ephemeris (hereinafter referred to as the "predicted ephemeris") downloaded from a server on the Internet and used for positioning, thereby enabling short-term positioning over a long period of about one month (for example, Japanese Patent Application Laid-Open No. 2013-195324). However, since the predicted ephemeris is predicted data, the deviation from the original orbital information increases as the number of days from the date of acquisition passes, resulting in reduced positioning accuracy. Therefore, the validity period of the predicted ephemeris is generally set to approximately three days from the date of server release.

[0004] In recent years, users have been equipped with information processing devices such as wearable devices and motion sensors equipped with built-in GPS receivers to locate users during activities such as running. Consider the case where the validity period of the predicted ephemeris has expired while the user is being positioned using the predicted ephemeris. Summary of the Invention

[0005] The present invention has been made in view of the above-mentioned actual situation, and an object thereof is to provide an information processing device, a positioning method, and a program that can continue positioning an object even when the validity period of the predicted ephemeris has expired during positioning.

[0006] In order to achieve the above-mentioned object, the information processing device involved in the present invention is equipped with an object, and is characterized in that it comprises: a receiving unit for receiving a positioning signal for positioning from a positioning satellite; an actual ephemeris acquisition unit for acquiring actual orbital information data of the positioning satellite, that is, an actual ephemeris, based on the positioning signal received by the receiving unit; a predicted ephemeris acquisition unit for acquiring a predicted ephemeris with a set validity period, which is predicted data obtained by predicting the orbital information of the positioning satellite; a judgment unit for judging whether the remaining time until the validity period is less than or equal to a judgment time set to a time greater than or equal to a maximum time assumed that the object is in a certain state; and a positioning unit for executing an actual ephemeris acquisition operation of the actual ephemeris acquisition unit based on the positioning signal received by the receiving unit when it is judged that the remaining time until the validity period is less than or equal to the judgment time, and positioning the object based on the actual ephemeris acquired by executing the actual ephemeris acquisition operation.

[0007] Effects of the Invention

[0008] According to the present invention, even when the validity period of the predicted ephemeris has expired during positioning, positioning of the object can be continued. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram showing a usage example of the information processing device according to the embodiment of the present invention.

[0010] Figure 2 This is a block diagram showing the configuration of an information processing device according to an embodiment of the present invention.

[0011] Figure 3 This is a flowchart showing the flow of positioning processing according to the embodiment of the present invention.

[0012] Figure 4 It is a figure for demonstrating the effect of this invention.

[0013] Figure 5 This is a flowchart (part 1) showing the flow of positioning processing according to a modification example of the embodiment of the present invention.

[0014] Figure 6 It is a diagram showing a configuration example of a determination time setting table.

[0015] Figure 7 This is a flowchart (part 2) showing the flow of positioning processing according to a modification of the embodiment of the present invention.

[0016] Figure 8 This is a flowchart (part 3) showing the flow of positioning processing according to a modification of the embodiment of the present invention.

[0017] Figure 9A This is a diagram (part 1) for explaining an example of setting the determination time based on positioning schedule information.

[0018] Figure 9B This is a diagram (part 2) for explaining an example of setting the determination time based on positioning schedule information. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[0020] like Figure 1 As shown, the information processing device 1 of the embodiment of the present invention is mounted on the waist of a user, for example, and acquires the user's position information (positioning) based on a GPS signal as a positioning signal, which is transmitted from a plurality of GPS satellites 2 as positioning satellites. This information processing device 1 is mainly intended to be used for positioning users participating in a full marathon. Figure 2 As shown, the information processing device 1 includes a communication unit 110, a GPS receiving unit 120, a timer unit 130, an input unit 140, an output unit 150, a storage unit 160, and a control unit 170. These units are electrically connected to each other via a bus BL1. Furthermore, the information processing device 1 can also be attached to a part of the user's body other than the waist (e.g., a wrist or ankle).

[0021] The communication unit 110 is an interface for communicating with an external device 3 such as a smartphone via short-range wireless communication such as Bluetooth (registered trademark). For example, the predicted ephemeris table described later is obtained from the external device 3 via the communication unit 110. Alternatively, the communication unit 110 may be an interface for wired communication such as USB.

[0022] The GPS receiver 120, equipped with a GPS receiving antenna (not shown), captures and receives GPS signals transmitted from each GPS satellite 2. The GPS signals received from GPS satellites 2 include actual ephemeris, which represents the actual orbital information of the GPS satellites 2; time information indicating the exact transmission time of the GPS signals; and an almanac indicating approximate orbital information for all GPS satellites 2. The contents of these actual ephemeris and almanac data (parameters such as true anomaly) are well known, as disclosed in, for example, the non-patent document "Basic Knowledge of GPS / GNSS by Joyasu Sakai (Electronic Navigation Research Institute) https: / / www.enri.go.jp / ~sakai / pub / symp07a.pdf, January 7, 2020," and therefore a detailed description thereof will be omitted. The GPS receiver 120 functions as a receiving unit.

[0023] The timekeeping unit 130 includes, for example, a crystal oscillator, and uses a basic clock generated by the crystal oscillator to accurately measure the current date and time (current time) in the region where the information processing device 1 is located, based on UTC (Coordinated Universal Time). Alternatively, the control unit 170 may measure the current date and time using software, instead of the timekeeping unit 130.

[0024] The input unit 140 includes various switches and buttons, and receives user operations and outputs signals corresponding to the received operations to the control unit 170. For example, the input unit 140 receives instructions from the user to start positioning and instructions to end positioning.

[0025] The output unit 150 includes a liquid crystal display panel, an organic EL (electroluminescence) display panel, a power light, and the like, and displays, for example, a screen showing positioning results. Furthermore, the output unit 150 may transmit information indicating positioning results to the external device 3 via the communication unit 110, and display a screen showing positioning results on the external device 3.

[0026] The storage unit 160 is, for example, a rewritable nonvolatile flash memory, a hard disk drive, or other storage device. The storage unit 160 stores various programs and data executed by the control unit 170. For example, the storage unit 160 stores an actual ephemeris storage DB (database) 161, a predicted ephemeris storage DB 162, and determination time information 163.

[0027] The actual ephemeris storage DB 161 stores the actual ephemeris, which is actual orbital information data for each GPS satellite 2, along with date and time information indicating the actual ephemeris' validity period. In this embodiment, for example, the validity period of the actual ephemeris, which can be used for positioning, is four hours (±2 hours from the epoch time included in the actual ephemeris). The validity period is set to the date and time approximately two to four hours after the GPS signal containing the actual ephemeris is received. Furthermore, the actual ephemeris for each GPS satellite 2 is updated in a two-hour cycle. This validity period is set based on the current time measured by the timekeeping unit 130. Actual ephemeris that has exceeded its validity period cannot be used for positioning due to reduced accuracy. Alternatively, the actual ephemeris storage DB 161 may be located within the GPS receiving unit 120.

[0028] The predicted ephemeris storage DB 162 stores predicted ephemeris, which is prediction data obtained by long-term prediction of the orbital information of each GPS satellite 2, along with date and time information indicating the validity period of the predicted ephemeris. In this embodiment, the validity period of the predicted ephemeris, which can be used for positioning, is longer than that of the actual ephemeris, for example, three days. For example, the validity period is set to 24:00 (UTC) three days after the predicted ephemeris is issued by a server (an external device described later). Predicted ephemeris that has exceeded its validity period cannot be used for positioning due to its reduced accuracy. The data content (parameters) of the predicted ephemeris are substantially the same as those of the actual ephemeris, but its validity period is longer than that of the actual ephemeris, and accordingly, the predicted ephemeris contains more data. Alternatively, the predicted ephemeris storage DB 162 can be located within the GPS receiver 120.

[0029] The judgment time information 163 indicates the time (judgment time) used to determine whether the actual ephemeris or the predicted ephemeris should be used when performing positioning by the positioning unit 174, described later. In this embodiment, the judgment time is set to, for example, eight hours, which is the maximum time (time limit) assumed for a full marathon runner, plus one hour. This is shorter than the validity period of the predicted ephemeris and longer than the validity period of the actual ephemeris. Thus, the judgment time is set to a time associated with the activity of the subject being positioned. Alternatively, the judgment time may be any other appropriate length of time, as long as it is at least the maximum time.

[0030] The control unit 170 includes at least one CPU (Central Processing Unit) as a processor and at least one ROM (Read Only Memory) and RAM (Random Access Memory) as memories (none shown). The CPU uses the RAM as working memory and appropriately executes various programs stored in the ROM and storage unit 160, thereby controlling the aforementioned components. As a functional configuration related to the present invention, the control unit 170 includes an actual ephemeris acquisition unit 171, a predicted ephemeris acquisition unit 172, a determination unit 173, and a positioning unit 174.

[0031] The actual ephemeris acquisition unit 171 demodulates the GPS signals received (captured) by the GPS receiver 120 from each GPS satellite 2 to acquire the actual ephemeris, and stores the actual ephemeris in the actual ephemeris storage DB 161 along with information indicating its expiration date. The actual ephemeris acquisition unit 171 acquires the actual ephemeris when the expiration date of the actual ephemeris stored in the actual ephemeris storage DB 161 has expired, when no valid predicted ephemeris is stored in the predicted ephemeris storage DB 162 at the start of positioning, or when the remaining time from the current point in time to the expiration date of the predicted ephemeris is less than the determination time. The actual ephemeris acquisition unit 171 functions as actual ephemeris acquisition means. Alternatively, the actual ephemeris acquisition unit 171 may be provided within the GPS receiver 120.

[0032] The predicted ephemeris acquisition unit 172 acquires the predicted ephemeris from the server via the external device 3 and stores it in the predicted ephemeris storage DB 162 along with information indicating its expiration date. The server manages the predicted ephemeris and periodically distributes the predicted ephemeris to the external device 3. Alternatively, the predicted ephemeris may be acquired from another appropriate external device other than the server. The predicted ephemeris acquisition unit 172 acquires the predicted ephemeris at a time when, for example, the information processing device 1 is able to communicate with the external device 3. At this time, the predicted ephemeris stored in the predicted ephemeris storage DB 162 is updated to the latest ephemeris. The predicted ephemeris acquisition unit 172 functions as predicted ephemeris acquisition means.

[0033] The determination unit 173 determines whether the positioning unit 174 uses the predicted ephemeris or the actual ephemeris for positioning. Specifically, the determination unit 173 determines whether the remaining time from the current time point to the expiration date of the predicted ephemeris stored in the predicted ephemeris storage DB 162 is less than or equal to the determination time indicated by the determination time information 163 stored in the storage unit 160. If the determination unit 173 determines that the remaining time from the current time point to the expiration date of the predicted ephemeris is less than or equal to the determination time, the positioning unit 174 causes the GPS receiving unit 120 to receive GPS signals and uses the actual ephemeris based on the received GPS signals for positioning. On the other hand, if the determination unit 173 determines that the remaining time from the current time point to the expiration date of the predicted ephemeris is not less than or equal to the determination time, the positioning unit 174 uses the predicted ephemeris obtained from the server for positioning. The determination unit 173 functions as a determination unit.

[0034] The positioning unit 174 positions the user equipped with the information processing device 1 based on the GPS signals received by the GPS receiving unit 120 from each GPS satellite 2, the actual ephemeris, and the predicted ephemeris. The positioning unit 174 functions as a positioning means.

[0035] Specifically, positioning unit 174 calculates the distance between GPS satellite 2 and information processing device 1 based on the time indicated by the time information included in the GPS signal and the current time measured by timekeeping unit 130. Positioning unit 174 performs this distance calculation for at least four GPS satellites 2. Furthermore, positioning unit 174 calculates the position of each GPS satellite 2, for which the distance was calculated, at the time the GPS signal was transmitted, based on the actual or predicted ephemeris determined by determination unit 173 to be used. Positioning unit 174 then calculates the current position (e.g., latitude, longitude, altitude, etc.) of the user equipped with information processing device 1 based on the thus-calculated distance to each GPS satellite 2 and the position of each GPS satellite 2, thereby locating the user. This method of calculating positioning is well known, as disclosed in the aforementioned non-patent literature, and therefore a detailed description thereof will be omitted.

[0036] Next, the positioning process performed by the information processing device 1 will be described. Before the start of the race, a user participating in a full marathon race operates the input unit 140 of the information processing device 1 mounted on the waist, instructs the information processing device 1 to start positioning, and then starts the race. In accordance with this instruction, the information processing device 1 performs Figure 3 Positioning process shown.

[0037] First, the determination unit 173 determines whether the remaining time from the current time point to the expiration date of the predicted ephemeris stored in the predicted ephemeris storage DB 162 is less than or equal to the determination time (step S101). In this case, the determination unit 173 uses the time from the current time point measured by the timekeeping unit 130 to the expiration date of the predicted ephemeris as the remaining time from the current time point to the expiration date of the predicted ephemeris.

[0038] If the remaining time from the current time point to the expiration date of the predicted ephemeris is not less than the determination time (step S101: No), the control unit 170 restarts the information processing device 1 by performing a hot boot (step S102). The positioning unit 174 then locates the user based on the predicted ephemeris stored in the predicted ephemeris storage DB 162 and the GPS signal captured by the GPS receiving unit 120 (step S103). Alternatively, the process of step S103 may be performed without performing a hot boot (step S102).

[0039] On the other hand, if the remaining time from the current time point to the expiration date of the predicted ephemeris is less than the determination time (step S101: Yes), the control unit 170 restarts the information processing device 1 using a cold boot (step S104). Consequently, when the remaining time from the current time point to the expiration date of the predicted ephemeris is less than the determination time, the positioning unit 174 causes the actual ephemeris acquisition unit 171 to demodulate the GPS signal captured (received) by the GPS receiving unit 120 and acquire the actual ephemeris (step S105). The acquired actual ephemeris is stored in the actual ephemeris storage DB 161. The positioning unit 174 then locates the user based on the actual ephemeris acquired in step S105 and the GPS signal captured by the GPS receiving unit 120 (step S106).

[0040] Afterwards, the user positioning started in steps S102, S103, or steps S104 to S106 continues while the user is playing. Then, when the game ends, the user operates input unit 140 to instruct the user to end positioning. Upon receiving this instruction (step S107: Yes), the positioning process ends.

[0041] Alternatively, instead of executing the restart based on the cold start (step S104) each time positioning is performed, it is possible to determine whether the restart can be executed based on the remaining time from the current time point to the expiration date of the actual ephemeris stored in the actual ephemeris storage DB 161. When the remaining time is shorter than a lower limit (e.g., 30 minutes) and the reliability of the actual ephemeris becomes low, the restart based on the cold start is executed. When the remaining time is greater than the lower limit, the restart based on the cold start is not executed, but the stored actual ephemeris is acquired (read out), and positioning is performed using the acquired actual ephemeris.

[0042] Furthermore, other methods can be used as long as positioning using the acquired actual ephemeris can be performed when the remaining time from the current time point to the expiration date of the predicted ephemeris is less than the determination time. For example, if the remaining time from the current time point to the expiration date of the predicted ephemeris is less than the determination time (step S101: Yes), instead of performing a cold restart, the actual ephemeris stored in the actual ephemeris storage DB 161 can be deleted, and then a new actual ephemeris can be retrieved by executing step S105, and positioning can be performed using this retrieved actual ephemeris (step S106). Similar to the restart described above, such deletion of the stored actual ephemeris can be performed not every time positioning is performed, but rather the deleting of the stored actual ephemeris can be determined based on the remaining time from the current time point to the expiration date of the stored actual ephemeris.

[0043] Next, use Figure 4The effects of the present invention will now be described. In this figure, the three-day period from time Ta to time Tc represents the period during which the predicted ephemeris stored in predicted ephemeris storage DB 162 is valid. Therefore, time Tc represents the expiration date of the predicted ephemeris. Furthermore, time Tb represents the time determined from time Tc, which is the expiration date of the predicted ephemeris, that is, eight hours prior.

[0044] Here, consider the case where the above positioning process is started at a time between time Ta and time Tb. In this case, since the remaining time until the validity period of the predicted ephemeris is not less than the judgment time ( Figure 3 If the result of step S101 is "No," information processing device 1 restarts with a hot start and uses the stored, valid predicted ephemeris to locate the user in the competition (steps S102-S103). In this case, the predicted ephemeris remains valid until at least the eight hours, the determination time, have passed since positioning began. Therefore, positioning of the user in the competition is not interrupted due to the expiration of the predicted ephemeris. Furthermore, in this case, since the system is restarted with a hot start, positioning can be started relatively quickly.

[0045] On the other hand, consider the case where the positioning process is started at a time between time Tb and Tc. In this case, since the remaining time until the validity period of the predicted ephemeris is less than the judgment time ( Figure 3 (Step S101: Yes), the information processing device 1 restarts from a cold start and uses the actual ephemeris obtained from the GPS signal captured when the remaining time until the validity period of the predicted ephemeris is less than the determination time to perform positioning of the user (steps S104-S106). Therefore, although the predicted ephemeris is valid at the start time of positioning processing, if there is a possibility that the validity period of the predicted ephemeris will expire during the competition, positioning based on the actual ephemeris is performed from the positioning start time. This can prevent the positioning of the user in the competition from being interrupted due to the expiration of the validity period of the predicted ephemeris.

[0046] Thus, according to this embodiment, if the remaining time until the validity period of the predicted ephemeris is less than the determination time, even if a valid predicted ephemeris exists, the latest GPS signal captured by the GPS receiver 120 is demodulated to obtain the actual ephemeris, and positioning is performed based on the obtained actual ephemeris. Therefore, even if the validity period of the predicted ephemeris has expired during positioning, positioning of the target object can continue.

[0047] Furthermore, according to this embodiment, positioning is performed based on the predicted ephemeris if the remaining time until the validity period of the predicted ephemeris is not less than the determination time. Therefore, if the likelihood of the predicted ephemeris expiring during positioning is low, positioning can be started immediately using the predicted ephemeris.

[0048] Furthermore, according to this embodiment, the determination time is set to 8 hours, which is longer than the maximum time (e.g., the typical 7-hour time limit for full marathon competitions) that the user being positioned is expected to be in a competitive state (e.g., a full marathon). Therefore, based on the relationship between the validity period of the predicted ephemeris and the time the object is in a certain state, it is possible to appropriately position the object using the actual ephemeris.

[0049] (Variation)

[0050] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

[0051] For example, in the above embodiment, the information processing device 1 is described as locating a user who is running a marathon. However, the user status in which the information processing device 1 locates is not limited to this. For example, the information processing device 1 can also be used to locate a user who is participating in a cycling race or orienteering. Furthermore, the location of the target is not limited to humans; the information processing device 1 can also be used to locate animals such as racehorses and objects such as cars.

[0052] In addition, in the above embodiment, the determination time is described as 8 hours, but the determination time is not limited to this. For example, the control unit 170 can also execute Figure 5 The positioning process shown allows the user to set the determination time. In this case, the control unit 170 functions as a setting unit.

[0053] In this positioning process, first, the control unit 170 receives an input of a judgment time from the user or the external device 3 via the input unit 140 or the communication unit 110 (step S11). Then, the control unit 170 stores the judgment time information 163 indicating the received judgment time in the storage unit 160 (step S12). In addition, if the judgment time information 163 is already stored in the storage unit 160, the control unit 170 updates the judgment time information 163 to the judgment time information 163 indicating the received judgment time. Then, the following operations are performed. Figure 3 The steps S101 to S107 are substantially the same. Thus, the user can set the determination time to a time that suits his or her own activities. In addition, the above steps S11 to S12 can be performed separately from the positioning process.

[0054] Furthermore, the control unit 170 may receive a designation of a user's state to be positioned in the information processing device 1 from the user or the external device 3 via the input unit 140 and the communication unit 110, and set the determination time to a time corresponding to the designated state. Figure 6 The judgment time setting table shown is stored in the storage unit 160. Then, by executing Figure 7 In the positioning process shown, the control unit 170 can refer to the determination time setting table to set the determination time according to the state of the designated user.

[0055] In this positioning process, first, the control unit 170 receives the user's state designation from the user or the external device 3 via the input unit 140 or the communication unit 110 (step S21). Figure 6 The judgment time setting table shown in the figure is used to obtain the judgment time corresponding to the accepted user status (step 22). For example, when the designation of "5 km marathon" is accepted as the user status, the judgment time of "1 hour" is obtained. Then, the control unit 170 stores the judgment time information 163 indicating the obtained judgment time in the storage unit 160 (step S23). In addition, when the judgment time information 163 is already stored in the storage unit 160, the control unit 170 updates the judgment time information 163 to the judgment time information 163 indicating the obtained judgment time. Then, the subsequent execution of the judgment time information 163 is performed. Figure 3 The steps S101 to S107 of the above method can be substantially the same. Thus, the determination time can be set to an appropriate time corresponding to the state of the user performing positioning. In addition, the above steps S21 to S23 can also be performed separately from the positioning process.

[0056] In addition, the control unit 170 can also receive the designation of positioning schedule information indicating the scheduled period for performing positioning (positioning scheduled period) from the user or the external device 3 via the input unit 140 and the communication unit 110, set the judgment time based on the received positioning schedule information, and perform positioning processing based on the set judgment time. Figure 8 A flowchart showing the positioning process in this case is shown.

[0057] In this positioning process, the control unit 170 first obtains positioning schedule information via the input unit 140 and the communication unit 110 (step S31). Alternatively, if positioning schedule information is already stored in the storage unit 160, the control unit 170 may also obtain this positioning schedule information. Next, the control unit 170 determines whether the predicted ephemeris validity period is included within the scheduled positioning period indicated by the obtained positioning schedule information (step S32).

[0058] When the validity period of the predicted ephemeris is included in the measurement scheduled period (step S32: yes), the control unit 170 sets the judgment time to start from 1 hour before the start time of the positioning scheduled period (step S33). Thus, in the event that the validity period of the predicted ephemeris may expire during the positioning scheduled period, the start time point of the positioning scheduled period must be included in the judgment time. In addition, "1 hour ago" here is arbitrary and can also be other times (such as "30 minutes ago", etc.), which are sufficient to include the start time point of the positioning scheduled period in the judgment time. Then, the following execution is performed with Figure 3 Steps S101 to S107 may be substantially the same process.

[0059] On the other hand, if the validity period of the predicted ephemeris is not included in the measurement scheduled period (step S32: No), the control unit 170 sets the judgment time to the set minimum time (for example, 1 hour) (step S34). This is because there is no possibility that the validity period of the predicted ephemeris will expire during the positioning scheduled period, so there is no need to set a long judgment time. In addition, the judgment time can also be set to 0 here. Then, the following execution is performed Figure 3 The steps S101 to S107 may be substantially the same as those in the above. In addition, the above steps S31 to S34 may be performed separately from the positioning process.

[0060] Next, a specific example is given to illustrate the above positioning process. Figure 9A As shown, in the case where the time Tc which is the validity period of the predicted ephemeris is included in the time T1 to T2 which is the scheduled positioning period indicated by the positioning schedule information ( Figure 8 If step S32 returns Yes, the control unit 170 sets the determination time to the period from time Tb, one hour before the start time T1 of the scheduled positioning period, to time Tc (step S33). This allows positioning to be performed based on the actual ephemeris during the scheduled positioning period, allowing continued positioning even if the validity period of the predicted ephemeris expires midway.

[0061] In addition, if Figure 9B As shown, in the case where the time T1 to T2 of the scheduled positioning period indicated as the positioning schedule information does not include the time Tc which is the validity period of the predicted ephemeris ( Figure 8 If the result of step S32 is "No", the control unit 170 sets a minimum determination time (e.g., 60 minutes) from time Tb to time Tc (step S34). This allows positioning to be started in a shorter time by performing positioning using the predicted ephemeris based on a hot start when there is no possibility of the predicted ephemeris expiring during the scheduled positioning period.

[0062] Furthermore, in the above embodiment, the remaining time from the current time point to the expiration date of the predicted ephemeris is the time from the current time point measured by the timer unit 130 to the expiration date of the predicted ephemeris. However, a counter value calculated as follows may also be used. Specifically, the expiration date of the predicted ephemeris obtained from the server is divided by a certain unit time (e.g., 1 minute) to convert the value into a counter value. Each time the unit time elapses based on the base clock of the timer unit 130 from the time the predicted ephemeris is obtained from the server, the counter value is decremented by 1, thereby calculating the remaining time until the expiration date of the predicted ephemeris. In this case, the determination time is also converted into a counter value by dividing the unit time. Although the claims refer to "remaining time" and "determination time" as "time," specifying both using such a counter value is also within the scope of the present invention.

[0063] Furthermore, in the above embodiment, the predicted ephemeris is obtained from a server as an external device, but the predicted ephemeris may be calculated and obtained in the information processing device 1. The method of calculating the predicted ephemeris is well known, and therefore a detailed description thereof is omitted.

[0064] Furthermore, as a positioning system, similar systems other than GPS can be used (such as GLONASS (Global Navigation Satellite System) of the Russian Federation, GALILEO of the EU (European Union), BeiDou and COMPASS of the People's Republic of China, and IRNSS (Indian Regional Navigation Satellite System) of India).

[0065] Furthermore, the above series of processing can be executed by hardware or software. Figure 2 The functional structure is merely an example and is not particularly limited. That is, as long as the information processing device 1 has the function of executing the above series of processing as a whole, the functional blocks used to implement the function are not particularly limited. Figure 2 example.

[0066] Furthermore, one functional block may be composed of hardware alone, software alone, or a combination thereof.

[0067] The functional structure in this embodiment is realized by a processor that performs arithmetic processing. Among the processors that can be used in this embodiment, in addition to processors composed of various processing device units such as a single processor, multiple processors, and multi-core processors, it also includes a structure obtained by combining these various processing devices with processing circuits such as ASIC (Application Specific Integrated Circuit) and FPGA (Field-Programmable Gate Array).

[0068] Furthermore, the various functions of the information processing device 1 can also be implemented by a conventional computer. Specifically, in the above embodiment, the program for the positioning processing performed by the information processing device 1 is pre-stored in the ROM of the control unit 170. However, the program can also be stored on a computer-readable recording medium such as a floppy disk, CD-ROM (Compact Disc Read Only Memory), DVD (Digital Versatile Disc), MO (Magneto-Optical Disc), memory card, or USB (Universal Serial Bus) memory and distributed, and the program can be read and installed in a computer, thereby forming a computer capable of implementing the aforementioned functions.

[0069] As mentioned above, although the preferred embodiment of the present invention was described, the present invention is not limited to the specific embodiment involved, and the present invention includes the invention described in the claims and the equivalent scope thereof.

Claims

1. An information processing device, equipped on an object, characterized in that: have: A receiving unit, receiving a positioning signal from a positioning satellite for positioning; an actual ephemeris obtaining unit, configured to obtain actual orbit information data of the positioning satellite, namely, actual ephemeris, based on the positioning signal received by the receiving unit; a predicted ephemeris acquisition unit that acquires a predicted ephemeris with a set validity period, which is prediction data obtained by predicting orbital information of the positioning satellite; a determination unit for determining whether the remaining time until the expiration date is equal to or shorter than a determination time set to be equal to or longer than a maximum time during which the object is assumed to be in a certain state; as well as The positioning unit, when determining that the remaining time until the expiration date is less than or equal to the determination time, executes an actual ephemeris acquisition operation by the actual ephemeris acquisition unit based on the positioning signal received by the receiving unit, and positions the object based on the actual ephemeris acquired by the actual ephemeris acquisition operation. The determination time is shorter than a valid period of the predicted ephemeris and longer than a valid period of the actual ephemeris.

2. The information processing device according to claim 1, wherein The positioning unit positions the object based on the acquired predicted ephemeris when determining that the remaining time until the expiration date is not less than the determination time.

3. The information processing device according to claim 1 or 2, wherein: The information processing device further includes a setting unit capable of setting the determination time.

4. The information processing device according to claim 3, wherein: The setting unit sets the determination time to a time associated with the specified state of the object. The information processing apparatus according to claim 3 , wherein: The setting unit sets the determination time to a time associated with the action content of the object. The information processing apparatus according to claim 3 , wherein: The setting unit sets the determination time based on positioning schedule information indicating a predetermined period during which positioning of the object is to be performed.

7. A positioning method, which is a positioning method equipped in an information processing device of an object, characterized in that: have: an actual ephemeris acquisition step of acquiring actual orbit information data of the positioning satellite, namely, actual ephemeris, based on a positioning signal for positioning received by a receiving unit from the positioning satellite; a predicted ephemeris acquisition step of acquiring a predicted ephemeris with a set validity period, which is prediction data obtained by predicting orbital information of the positioning satellite; a determination step of determining whether the remaining time until the expiration date is equal to or shorter than a determination time set to be equal to or longer than a maximum time for which the object is assumed to be in a certain state; as well as a positioning step of, when it is determined that the remaining time until the expiration date is less than or equal to the determination time, executing an actual ephemeris acquisition operation of the actual ephemeris acquisition step based on the positioning signal received by the receiving unit, and positioning the object based on the actual ephemeris acquired by executing the actual ephemeris acquisition operation; The determination time is shorter than a valid period of the predicted ephemeris and longer than a valid period of the actual ephemeris.

8. A non-temporary storage medium, characterized in that: A program is stored that causes a computer equipped with the object to function as the following means: an actual ephemeris acquisition unit for acquiring actual orbit information data of the positioning satellite, namely, actual ephemeris, based on the positioning signal for positioning received by the receiving unit from the positioning satellite; a predicted ephemeris acquisition unit that acquires a predicted ephemeris with a set validity period, which is prediction data obtained by predicting orbit information of the positioning satellite; a determination unit for determining whether the remaining time until the expiration date is equal to or shorter than a determination time set to be equal to or longer than a maximum time during which the object is assumed to be in a certain state; as well as The positioning unit, when determining that the remaining time until the expiration date is less than or equal to the determination time, executes an actual ephemeris acquisition operation by the actual ephemeris acquisition unit based on the positioning signal received by the receiving unit, and positions the object based on the actual ephemeris acquired by the actual ephemeris acquisition operation. The determination time is shorter than a valid period of the predicted ephemeris and longer than a valid period of the actual ephemeris.

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