Device with positioning function, positioning result receiving device and positioning result utilization system

Abstract

Device comprising a positioning function: a satellite receiver (230) which receives signals from artificial satellites used in a satellite positioning system; a positioning section (S1) which measures the position of a host device based on the signals received by the satellite receiver from the artificial satellites; an authentication information acquisition section (S5) which acquires authentication information from an authentication center (120) located outside the host device, the authentication information being used to authenticate whether the signals from the artificial satellites are legitimate signals; an authentication section (S9, S10, S11) which, based on the authentication information, authenticates whether the signals received by the satellite receiver are the legitimate signals from the artificial satellites; an authentication level calculation section (S22) which calculates an authentication level based on at least one of a set of artificial satellites authenticated by the authentication section or a ratio of the artificial satellites authenticated by the authentication section to the artificial satellites used for positioning the host device by the positioning section; and a positioning result transfer processing section (S24) which successively transfers a positioning result measured by the positioning section to a device other than the host device, wherein the positioning result transfer processing section appends the authentication level calculated by the authentication level calculation section to the positioning result before transferring the positioning result.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device with a positioning function that measures a position of the device based on signals received from an artificial satellite used in a satellite positioning system. The present invention also relates to a positioning result receiving device that receives information about a position measured by the device with a positioning function. The present invention further relates to a positioning result utilization system that includes the device with a positioning function and the positioning result receiving device. STATE OF THE ART

[0002] Conventionally, a technique is known that measures a position of a host device by allowing a receiver to receive signals from an artificial satellite used in a satellite positioning system.

[0003] In recent years, however, a repeater designed to reproduce signals from an artificial satellite and a simulator capable of generating artificial satellite signals in a pseudo-manner have been developed. This poses a problem in which a malicious person could falsify or manipulate position information.

[0004] Meanwhile, a technique disclosed in JP 2013-130395 A authenticates whether a signal received by a host device is a legitimate signal from an artificial satellite used in a satellite positioning system. The technique disclosed in Patent Literature 1 allows a receiver to access a database in an authentication center using a satellite number and satellite time included in the signal received by the host device from the artificial satellite and acquires data to be used to authenticate the artificial satellite. The receiver then uses the data acquired from the authentication center to authenticate whether the signal received by the host device is a legitimate signal from the artificial satellite used in the satellite positioning system.

[0005] When using the technique disclosed in JP 2013-130395 A, the receiver must authenticate whether individual signals from multiple artificial satellites used for positioning are legitimate signals during each positioning operation. Therefore, if authentication must be performed on the signals from all the artificial satellites used for positioning, a significant amount of waiting time is required before completing authentication. This is because, for example, it is time-consuming to access the authentication center to acquire the data.

[0006] Assume that a positioning result received by the receiver is to be used by an application or system that requires positioning information. For example, the positioning result is required to be highly reliable in a system that calculates parking fees based on positioning information. Thus, the system must wait until the authentication described above is fully completed. However, an application such as a game that uses positioning information does not require the positioning results to be highly reliable. Thus, in a gaming application, a significant amount of time is wasted if the positioning result received by the receiver is output after the authentication described above has been fully completed.

[0007] The closest prior art is shown in JP 2011 - 041 038 A.

[0008] The method and system for authenticating position information disclosed therein encrypts the position information with an encryption code that changes periodically to prevent, for example, the alteration of GPS data or forgery or spoofing by third parties.

[0009] US 2013 / 0 127 664 A1 discloses a method and apparatus for SPS authentication, for example, for use with GPS. The method may include receiving a first set of Y-codes from multiple satellites, generating authentication decisions using W-code estimates extracted from the first set of Y-codes for multiple satellites, and generating an authentication response according to the authentication decisions.

[0010] US 2012 / 0 208 557 A1 discloses a system, method and apparatus that enable determining the reliability of a position determined by a mobile device in response to navigation system signals.

[0011] The method in US 8 068 534 B2 relates to global positioning, which includes both the absolute geographical position and the relative position of an object relative to another object.

[0012] EP 2 397 868 A1 relates to a method for authenticating positioning data. The method provides an authenticable time and location information using a radio navigation signal receiver. SUMMARY OF THE INVENTION

[0013] The present invention has been conceived in view of the above circumstances. It is an object of the present invention to provide a device with a positioning function, a positioning result receiving device, and a positioning result utilization system, each of which enables flexible utilization of a positioning result by a system or application according to the positioning result reliability required by the application or system. The system or application operates based on the positioning result derived from signals transmitted from artificial satellites of a satellite positioning system.

[0014] This object is achieved by the device with a positioning function according to claims 1 and 4, the positioning result receiving device according to claim 9, and the positioning result utilization system according to claim 14. Further developments according to the invention are the subject of the dependent claims.

[0015] According to a first aspect of the present invention, a device with a positioning function includes a satellite receiver, a positioning section, an authentication information acquisition section, an authentication section, an authentication level calculation section, and a positioning result transmission processing section. The satellite receiver receives signals from artificial satellites used in a satellite positioning system. The positioning section measures a position of a host device based on the signals received by the satellite receiver from the artificial satellites.The authentication information acquisition section acquires authentication information from an authentication center located outside the host device, and the authentication information is used to authenticate whether the signals from the artificial satellites are legitimate signals. Based on the authentication information, the authentication section authenticates whether the signals received by the satellite receiver are legitimate signals from the artificial satellites. The authentication level calculation section calculates an authentication level based on at least one of a set of artificial satellites authenticated by the authentication section or a ratio of artificial satellites authenticated by the authentication section to the artificial satellites used for positioning the host device by the positioning section.The positioning result transmission processing section successively transmits a positioning result measured by the positioning section to a different device other than the host device, and the positioning result transmission processing section appends the authentication level calculated by the authentication level calculation section to the positioning result before transmitting the positioning result.

[0016] The above-described device with a positioning function enables a positioning result receiving device (hereinafter referred to as the receiving end device) to acquire the authentication level. The authentication level is obtained based on the number of artificial satellites successfully authenticated by the authentication information acquired from the authentication center to the artificial satellites used for positioning by the positioning unit, or the authentication level is obtained based on a ratio of the artificial satellites successfully authenticated by the authentication information acquired from the authentication center to the artificial satellites used for positioning by the positioning unit.It takes a considerable amount of time to complete authentication using the authentication information acquired from the authentication center. Therefore, a situation may frequently arise in which only some of the artificial satellites used for positioning by the positioning unit are authenticated using the authentication information. Even if only some of the artificial satellites used for positioning are authenticated as described above, the receiving end device is able to determine the degree of reliability of the positioning result by the authentication level. Therefore, whether an application or system using the positioning result should be executed or not can be determined based on the authentication level.For example, if the authentication level is low, an application or system requiring low positioning result reliability may be determined to be executable.

[0017] Consequently, the positioning result can be flexibly used based on the positioning result reliability required for an application or a system that uses the positioning result derived from signals transmitted from a plurality of artificial satellites used in a satellite positioning system.

[0018] According to a second aspect of the present invention, a positioning result receiving device includes a positioning result reception processing section, an execution section, and a usage determination section. The positioning result reception processing section receives a positioning result transmitted from a device with a positioning function. The device with a positioning function authenticates whether signals received by a satellite receiver are legitimate signals transmitted from artificial satellites used in a satellite positioning system.The positioning result received by the positioning result reception processing section is attached with an authentication level calculated based on at least one of a set of authenticated artificial satellites or a ratio of the authenticated artificial satellites to artificial satellites used when measuring the positioning result by the device with a positioning function. The execution section executes a positioning result utilization process, which is a process that utilizes the positioning result received by the positioning result reception processing section. The usage determination section determines whether the positioning result is to be used in the positioning result utilization process based on the authentication level attached to the positioning result received by the positioning result reception processing section.

[0019] With the positioning result receiving device described above, the positioning result receiving device is capable of determining the degree of reliability of a positioning result based on the authentication level when only some of the artificial satellites used for positioning by the device with a positioning function are authenticated. This allows the usage determination unit to determine whether an application or system using the positioning result is executable or not based on the authentication level. For example, if the authentication level is low, an application or system requiring low positioning result reliability can be determined to be executable.

[0020] Consequently, the positioning result can be flexibly used based on the positioning result reliability required for an application or a system that uses the positioning result derived from signals transmitted from a plurality of artificial satellites used in a satellite positioning system.

[0021] According to a third aspect of the present invention, a positioning result utilization system includes a device having a positioning function according to the first aspect of the present invention and a positioning result receiving device according to the second aspect of the present invention.

[0022] With the positioning result utilization system described above, the positioning result can be flexibly utilized based on the positioning result reliability required for an application or a system that uses the positioning result derived from signals transmitted from a plurality of artificial satellites used in a satellite positioning system.

[0023] According to a fourth aspect of the present invention, a device with a positioning function includes a satellite receiver, a positioning section, an authentication information acquisition section, an authentication section, an authentication level calculation section, an execution section, and a usage determination section. The satellite receiver receives signals from artificial satellites used for a satellite positioning system. The positioning section measures a position of a host device based on the signals received by the satellite receiver from the artificial satellites. The authentication information acquisition section acquires authentication information from an authentication center located external to the host device.The authentication information is used to authenticate whether the signals from the artificial satellites are legitimate signals. The authentication section authenticates, based on the authentication information, whether the signals received by the satellite receiver are legitimate signals from the artificial satellites. The authentication level calculation section calculates an authentication level based on at least one of a set of artificial satellites authenticated by the authentication section or a ratio of the artificial satellites authenticated by the authentication section to the artificial satellites used for positioning of the host device by the positioning section. The execution section executes a positioning result utilization process, which is a process that utilizes a positioning result measured by the positioning section.The usage determination section determines whether to use the positioning result measured by the positioning section in the positioning result usage process based on the authentication level calculated by the authentication level calculation section.

[0024] The above-described device with a positioning function enables a positioning result receiving device (hereinafter referred to as the receiving end device) to acquire the authentication level. The authentication level is obtained based on the number of artificial satellites successfully authenticated by the authentication information acquired from the authentication center to the artificial satellites used for positioning by the positioning unit, or the authentication level is obtained based on a ratio of the artificial satellites successfully authenticated by the authentication information acquired from the authentication center to the artificial satellites used for positioning by the positioning unit.It takes a considerable amount of time to complete authentication using the authentication information acquired from the authentication center. Therefore, a situation may frequently arise in which only some of the artificial satellites used for positioning by the positioning unit are authenticated using the authentication information. Even if only some of the artificial satellites used for positioning are authenticated as mentioned above, the receiving end device is able to determine the degree of reliability of the positioning result by the authentication level. Therefore, whether an application or system using the positioning result should be executed or not can be determined based on the authentication level.For example, if the authentication level is low, an application or system that enables low positioning result reliability may be determined to be executable.

[0025] Consequently, the positioning result can be flexibly used based on the positioning result reliability required for an application or a system that uses the positioning result derived from signals transmitted from a plurality of artificial satellites used in a satellite positioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: Fig. 1 is a diagram illustrating an exemplary outline configuration of a positioning result utilization system according to a first embodiment of the present invention; Fig. 2 is a block diagram illustrating an exemplary overview of an authentication center; Fig. 3 is a block diagram illustrating an exemplary outline configuration of an in-vehicle device according to the first embodiment; Fig. 4 is a flowchart illustrating an example of an authentication-related process in the in-vehicle device according to the first embodiment; Fig. 5 is a flowchart illustrating an example of a position information transmission-related process in the in-vehicle device according to the first embodiment; Fig. 6 is a flowchart illustrating an example of a position information utilization-related process in a roadside device according to the first embodiment; Fig. 7 is a flowchart illustrating an example of a road billing-related process in the roadside device according to a second modification of the present invention; Fig. 8A is a schematic diagram illustrating continuous position information; Fig. 8B is a schematic diagram illustrating discontinuous position information; Fig. 9 is a flowchart illustrating an example of a parking billing-related process in the roadside device according to a third modification of the present invention; Fig. 10 is a diagram illustrating an exemplary outline configuration of a positioning result utilization system according to a second embodiment of the present invention; Fig. 11 is a block diagram illustrating an exemplary overview configuration of a position information utilization device, Fig. 12 is a diagram illustrating an exemplary outline configuration of a positioning result utilization system according to a third embodiment of the present invention; Fig. 13 is a block diagram illustrating an exemplary overview configuration of a mobile terminal; Fig. 14 is a flowchart illustrating an example of a position information use-related process in the mobile terminal according to the third embodiment; Fig. 15 is a flowchart illustrating an example of a road billing-related process in the mobile terminal according to the second modification; and Fig. 16 is a flowchart illustrating an example of a road billing-related process in the mobile terminal according to the third modification of the present invention. EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0027] Embodiments of the present invention will now be described with reference to the accompanying drawings. (First embodiment)

[0028] As in Fig. As shown in FIG. 1, a positioning result utilization system 1 according to a first embodiment includes a monitoring station 110, an authentication center 120, a master control station 130, an in-vehicle device 200, and a roadside device 300. The in-vehicle device 200 corresponds to a device with a positioning function. The roadside device 300 corresponds to a positioning result receiving device.

[0029] The monitoring station 110 receives GPS radio waves transmitted from GPS satellites 2a-2c included in GPS, which is a satellite positioning system. The GPS satellites 2a-2c correspond to artificial satellites. If there is no need to distinguish the GPS satellites 2a-2c from each other, the GPS satellites will be referred to hereinafter as GPS satellites 2. As is well known, each of the GPS radio waves contains a navigation message (NAVI MSG). The monitoring station 110 demodulates a received GPS radio wave, extracts a navigation message, and transmits the extracted navigation message to the authentication center 120. The navigation message corresponds to a signal from an artificial satellite.When GPS radio waves are received from a plurality of GPS satellites 2, the navigation message for each of the received GPS radio waves is extracted from the GPS radio wave and transmitted to the authentication center 120.

[0030] The authentication center 120 generates parity data and an H-matrix based on the navigation message. The H-matrix is ​​an encryption key. The authentication center 120 then transmits a signal containing the parity data to the master control station 130. Furthermore, the authentication center 120 communicates with the in-vehicle device 200. The authentication center 120 will be described in detail later with reference to Fig. 2 are described.

[0031] The master control station 130 transmits the parity data received from the authentication center 120 to a quasi-zenith satellite (hereinafter referred to as the QZS) 3. The QZS 3 broadcasts a navigation message containing the parity data to the ground.

[0032] The in-vehicle device 200 is a navigation message authentication type in-vehicle device for a vehicle or a moving body. The in-vehicle device 200 communicates with the authentication center 120 and authenticates whether the navigation message received from a GPS satellite 2 is legitimate. Authentication is successively performed for all of the GPS satellites 2 used for positioning. However, performing authentication for each GPS satellite 2 takes a certain amount of time. Therefore, before completing authentication on all of the GPS satellites 2 used for positioning, some of the GPS satellites 2 are in authenticated states. Satellite authentication will be described in detail later with reference to Fig. 4 are described.

[0033] Furthermore, the in-vehicle device 200 measures its current position using navigation messages received from a plurality of GPS satellites 2. To measure the current position, it is necessary to use the navigation messages received from at least three GPS satellites 2.

[0034] Furthermore, the in-vehicle device 200 calculates the ratio of the number of GPS satellites 2 whose navigation messages are authenticated to the number of GPS satellites 2 used for positioning of a host device on which the positioning function is provided. The ratio of the number of GPS satellites 2 whose navigation messages are authenticated to the number of GPS satellites 2 used for positioning is hereinafter referred to as an authentication level (AUTH LV). For example, if one GPS satellite 2 is authenticated in a situation where three GPS satellites 2 are used for positioning, the authentication level is 1 / 3 (ie, 33.3%).The calculated authentication level is then appended to position information (POSI INFO) indicating the measured current position, and the position information is wirelessly transmitted to the outside along with the authentication level. The in-vehicle device 200 will be described in detail with reference to FIG. Fig. 3 are described.

[0035] The roadside device 300 is a terminal of a system that uses the position information transmitted from the in-vehicle device 200 to perform a process of providing a predetermined service. A typical service provision process is, for example, a billing process performed to automatically bill a user of a vehicle when the vehicle is parked in a paid parking lot or traveling on a toll road.

[0036] Further, based on the authentication level attached to the position information transmitted from the in-vehicle device 200, the roadside device 300 determines whether or not to use the position information in a position information utilization process. Based on the determination result, the roadside device 300 either uses the position information or not.

[0037] As in Fig. 2, the authentication center 120 includes a control unit 122, a data storage unit 124, and a communication unit 126.

[0038] The control unit 122 is provided by a computer including a main processor (CPU), a read-only memory (ROM), and a random access memory (RAM). The control unit 122 controls the data storage unit 124 and the communication unit 126. Furthermore, the control unit 122 functions as a RAND message generation section 1221, a SEED value generation section 1222, an H-matrix calculation section 1223, a parity calculation section 1224, and a signal processing section 1225 by allowing the CPU to utilize a temporary storage function of the RAM and execute programs stored in the ROM. The functions of these sections 1221-1225 can be configured to be similar to an embodiment disclosed in JP 2013-130395 A.

[0039] The RAND message generation section 1221 generates a RAND message (RAND MSG) from the navigation message acquired from the monitoring station 110. RAND is an abbreviation for Reference Authentication Navigation Data. The RAND message includes TOW (time of week), TOC (clock time), clock correction coefficient AF0, and clock correction coefficient AF1 in sequential order. The TOW, TOC, clock correction coefficient AF0, and clock correction coefficient AF1 are extracted from a navigation message bit string and are used to identify the time of signal generation. Furthermore, the RAND message includes an AS flag (anti-tampering flag) and a PRN (pseudo-random noise) ID, which is a satellite number. The AS flag and PRN ID are added to one end of the RAND message.It can be said that RANDs, which have a TOW and a PRN ID, indicate when a transmission is made from which GPS satellite. Furthermore, the RANDs are generated for each GPS satellite 2 whose signals are received by monitoring station 110, and at 6-second intervals, since the TOW changes at 6-second intervals and the RAND message contains the PRN ID.

[0040] The SEED value generating section 1222 generates a SEED value by generating a random number based on an input of a PC clock.

[0041] The H-matrix calculation section 1223 uses the SEED value generated by the SEED value generation section 1222 to calculate an H-matrix that corresponds to the SEED value on a one-to-one basis. A well-known hash function can be used as the H-matrix. For example, a parity check matrix for LDPC (Low-Density Parity Check) encryption can be used as the H-matrix. Furthermore, a matrix determined from the parity check matrix can be used as the H-matrix.

[0042] The parity calculation section 1224 calculates parity data based on the RAND message generated by the RAND message generation section 1221 and the H matrix calculated by the H matrix calculation section 1223. Specifically, the parity data is calculated by multiplying the RAND message by the H matrix.

[0043] The signal processing section 1225 inserts the parity data calculated by the parity calculation section 1224 and the RAND message used to calculate the parity data into the navigation message to be transmitted from the QZS 3. The signal processing section 1225 then transmits the processed navigation message to the master control station 130.

[0044] Further, at the time of the above signal insertion, the signal processing section 1225 associates the parity data calculated by the parity calculation section 1224, the RAND message used to calculate the parity data, the H matrix, and the SEED value used to calculate the H matrix, and stores the associated data in the data storage unit 124.

[0045] Each time the RAND message is generated by the RAND message generation section 1221, the signal processing section 1225 inserts the RAND message and parity data into the navigation message to be transmitted from the QZS 3. Therefore, each of the RAND message generation section 1221, the SEED value generation section 1222, the H-matrix calculation unit 1223, and the parity calculation section 1224 performs a process in response to each generation of the RAND message by the RAND message generation section 1221.

[0046] When the communication unit 126 receives the PRN ID, TOW, and the public key transmitted from the in-vehicle device 200, an H-matrix selection section 1226 examines H-matrices stored in the data storage unit 124 and selects an H-matrix associated with the received PRN ID and TOW. The H-matrix selection section 1226 then encrypts the selected H-matrix using the public key and returns the encrypted H-matrix to the in-vehicle device 200.

[0047] As in Fig. 3, the in-vehicle device 200 includes a communication unit 210, a control unit 220, and a satellite receiver 230. The navigation message broadcast from the QZS 3 is received by a receiving unit 211 included in the communication unit 210 of the in-vehicle device 200.

[0048] The communication unit 210 includes the receiving unit 211 and a transmitting unit 212. The communication unit 210 has a narrow-range communication function and a wide-range communication function. The narrow-range communication function has a communication range of, for example, several hundred meters. The wide-range communication function has a communication range of, for example, several kilometers. The wide-range communication function makes it possible to establish communication with a base station of a public communication network in order to communicate with a remote communication instrument within the communication range of the public communication network. The narrow-range communication function is executed to communicate with a communication unit 310 of the roadside device 300.The wide area communication function is executed to communicate with the communication unit 126 in the authentication center 120.

[0049] The satellite receiver 230 receives radio waves transmitted from the GPS satellites 2 and the QZS 3 at predetermined time intervals.

[0050] The control unit 220 is provided by a computer that includes a CPU, a ROM and a RAM and controls the communication unit 210 and the satellite receiver 230. Furthermore, the control unit 220 executes a Fig. 4 and one in Fig. 5 by allowing the CPU to use a temporary storage function of the RAM and execute programs stored in the ROM.

[0051] The following will describe the authentication-related process with reference to the flowchart of Fig. 4. The authentication-related process is performed by the control unit 220 of the in-vehicle device 200 to authenticate whether a signal received by the satellite receiver 230 is a legitimate navigation message from a GPS satellite 2. For example, the process described in the flowchart of Fig. 4 must be performed each time the satellite receiver 230 receives GPS radio waves from three or more GPS satellites 2.

[0052] Here, it is assumed that a signal from a repeater that reproduces a signal from a GPS satellite 2 or a signal from a simulator capable of generating a signal from a GPS satellite 2 in a pseudo manner may be mistakenly received by the satellite receiver 230 as a navigation message included in a GPS radio wave.

[0053] First, in step S1, the current position of a host device is measured based on the navigation messages contained in the GPS radio waves received from three or more GPS satellites 2. S1 corresponds to a positioning section.

[0054] In step S2, the navigation message received from the QZS 3 is acquired by the receiving unit 211.

[0055] In step S3, the PRN ID and TOW are extracted from the navigation message acquired in step S1.

[0056] In step S4, the PRN ID and TOW extracted in step S3 and the public key are transmitted from the transmission unit 212 to the authentication center 120. As mentioned earlier, the authentication center 120 encrypts the H-matrix defined by the PRN ID and TOW using the public key and then transmits the encrypted H-matrix to the in-vehicle device 200.

[0057] In step S5, the H-matrix transmitted from the authentication center 120 is acquired by the receiving unit 211. S5 corresponds to an authentication information acquisition section. In step S6, the encrypted H-matrix acquired in step S5 is decrypted using a secret key.

[0058] In step S7, a navigation message containing a PRN ID identical to the PRN ID transmitted in step S4 is selected from the GPS radio waves received from the GPS satellites 2, and a RAND message is generated based on the selected navigation message.

[0059] In step S8, comparative parity data is generated from the RAND message generated in step S7 and the H-matrix decrypted in step S6.

[0060] In step S9, a check is performed to determine whether the comparative parity data generated in step S8 is identical to the parity data extracted in step S3.

[0061] The H-matrix decrypted in step S6 is identical to the H-matrix used by the authentication center 120 to generate the parity data. The parity calculation section 1224 of the authentication center 120 calculates the parity data based on the H-matrix and the RAND message.

[0062] Consequently, if the comparative parity data generated in step S8 is identical to the parity data extracted in step S3, the RAND message generated in step S7 can be considered to be the same as the RAND message generated by the authentication center 120.

[0063] Therefore, if the comparative parity data generated in step S8 is identical to the parity data extracted in step S3 ("YES" in S9), the process proceeds to step S10. In step S10, it is determined that the authentication was successful. Conversely, if the two parity data are not identical to each other ("NO" in S9), the process proceeds to step S11. In step S11, it is determined that the authentication failed. S9 to S11 correspond to an authentication section. After completion of step S10 or S11, the process proceeds to step S12.

[0064] If in step S12 all the navigation messages used for positioning in step S1 have been determined to be either successfully authenticated or not successfully authenticated (“NO” in S12), the Fig. 4 is terminated. In contrast, if all the navigation messages used for positioning in step S1 are not determined to be successfully authenticated or not successfully authenticated ("YES" in S12), the process returns to step S2 to repeat steps S2 and subsequent steps.

[0065] The position information transmission related process will now be described with reference to the flowchart of Fig. 5. The position information transmission-related process is performed by the control unit 220 of the in-vehicle device 200 to transmit the position information to the roadside device 300. The position information transmission-related process is performed to transmit both the position information indicating the current position measured by the in-vehicle device 200 and the authentication level indicating the number or ratio of successfully authenticated GPS satellites 2 among the GPS satellites 2 used for positioning. The process shown in the flowchart of Fig. The process illustrated in Fig. 5 may be initiated when a request signal for position information is received from the communication unit 310 of the roadside device 300, or may be performed at predetermined time intervals.

[0066] The flowchart of Fig. 5 and the process shown in the flow chart of Fig. 4 are performed in parallel. Even if not all the navigation messages used for positioning are fully authenticated, the control unit 220 starts the process shown in the flowchart of Fig. 5 process shown.

[0067] First, the current position of the host device, which is determined in step S2 in the flowchart of Fig. 4 is measured, is acquired in step S21. The acquired current position is then stored in an electrically rewritable memory, such as a RAM or an EEPROM, included in the control unit 220. When the acquired current position is to be stored in the memory, a timestamp, which is information indicating a time at which the current position was measured, is appended to the acquired current position.

[0068] In step S22, the authentication level is calculated. The authentication level is the ratio of the number of GPS satellites 2 that are detected as shown in the flowchart of Fig. 4 are authenticated, to the number of GPS satellites 2 used to measure the current position acquired in step S21. For example, if one GPS satellite 2 is authenticated in a situation where three GPS satellites 2 are used for positioning, the authentication level is 33.3%. Step S22 corresponds to an authentication level calculation section.

[0069] The present embodiment has been described on the assumption that the authentication level represents the ratio of the number of authenticated GPS satellites 2 to the number of GPS satellites 2 used for positioning. Alternatively, the authentication level may represent the number of authenticated GPS satellites 2. For example, if four GPS satellites 2 are used for positioning and four GPS satellites are authenticated in a situation where such an alternative measure is used, the authentication level is defined as 4. As another example, a value defined based on the number of authenticated GPS satellites 2 and the ratio of authenticated GPS satellites among the GPS satellites 2 used for positioning may be used as the authentication level.As another example, a value defined based on the number of authenticated GPS satellites 2 and an arrangement of the authenticated GPS satellites 2 can be used as the authentication level. As described above, a value defined by the number of authenticated GPS satellites 2 and / or the ratio of authenticated GPS satellites 2 can be used as the authentication level.

[0070] In step S23, the current position and timestamp stored in the memory in step S21 are read. Then, the transmission data is generated in a standard format. The transmission data, which has the standard format, contains position information indicating the read current position, the timestamp, and the authentication level calculated in step S22.

[0071] The transmission data may additionally include the traveling direction and speed of the vehicle in which the in-vehicle device 200 is mounted. The vehicle's speed may be determined based on a value detected by a wheel speed sensor or by calculating the distance traveled by the vehicle per unit time from position information at multiple chronologically arranged points. The vehicle's traveling direction may be determined from the result of detection by a geomagnetic sensor or based on the extension direction of an approximate line determined by the least squares method from the position information at multiple chronologically arranged points.

[0072] In step S24, the transmission data generated in step S23 and containing the positioning information, the timestamp, and the authentication level are transmitted externally via the transmission unit 212. After completion of S24, the process is terminated. S24 corresponds to a positioning result transmission processing section.

[0073] The roadside device 300 includes the communication unit 310 and a control unit 320. The communication unit 310 communicates wirelessly with the communication unit 126 of the authentication center 120, and the communication unit 310 also communicates wirelessly with the communication unit 210 of the in-vehicle device 200.

[0074] The control unit 320 is provided by a computer that includes a CPU, a ROM, and a RAM and controls the communication unit 310. Furthermore, the control unit 320 performs a usage determination-related process that Fig. 6 by allowing the CPU to use a temporary storage function of the RAM and to execute programs stored in the ROM.

[0075] The usage-related process is now described with reference to the flowchart of Fig. 6. The usage determination-related process is performed by the control unit 320 of the roadside device 300 to determine the use of the position information transmitted from the in-vehicle device 200. The usage determination-related process is performed based on the authentication level attached to the position information transmitted from the in-vehicle device 200 to determine whether or not to use the position information in the position information utilization process, which is a process of utilizing the position information. The process shown in the flowchart of Fig. For example, the process illustrated in Figure 6 may be initiated when transmission data transmitted from the in-vehicle device 200 is received by the communication unit 310 of the roadside device 300. The position information utilization process corresponds to a positioning result utilization process.

[0076] First, in step S41, the authentication level is specified based on the position information reliability required for the position information utilization process, i.e., the authentication level required for the position information utilization process. The authentication level required for the position information utilization process is hereinafter referred to as the required authentication level (REQ AUTH LV).

[0077] In a case where the roadside device 300 performs only one type of position information utilization process and the required authentication level is a fixed value, the fixed value can be set as the required authentication level. In a case where the roadside device 300 performs multiple different types of position information utilization processes, the required authentication level appropriate for the position information utilization process to be performed by the roadside device 300 can be determined by referring to a predefined relationship between different position information utilization processes and corresponding required authentication levels.

[0078] For example, if the location information usage process is a billing process performed to bill the user for parking the vehicle in a paid parking lot or driving the vehicle on a toll road, the required authentication level is set to a high level because it is necessary to avoid incorrect billing. For example, if the location information usage process is a process for a game that uses location information but does not require highly reliable location information, the required authentication level is set to a low level because it is preferable to start the game immediately without waiting for the reliability to increase to a high level.As described above, the higher the position information reliability required for the position information utilization process, the higher the required authentication level.

[0079] When the required authentication level is a predetermined fixed value, the fixed value may be specified in advance in the roadside device without specifying the required authentication level in step S41 of the position information utilization process.

[0080] In step S42, the transmission data received by the communication unit 310 is acquired by the communication unit 310 to obtain the position information, timestamp, and authentication level included in the transmission data. Step S42 corresponds to a positioning result reception processing section.

[0081] In step S43, a check is performed to determine whether the authentication level acquired in step S42 equals the required authentication level determined in step S41. Assume that the location information utilization process is a billing process that bills the user for parking the vehicle in a paid parking lot or driving the vehicle on a toll road, and the required authentication level is 100%. In this case, if the authentication level acquired in step S42 is lower than 100%, the process determines that the required authentication level is not met. Assume that the location information utilization process is a process for a game that uses the location information, and that the required authentication level is 33%.In this case, in response to an increase in the authentication level to 33%, the process determines that the required authentication level is reached even if the authentication level acquired in step S42 is lower than 100%.

[0082] In step S43, if it is determined that the required authentication level is met ("YES" in S43), the process proceeds to step S44. In step S44, the location information acquired in step S41 is determined to be usable in the location information utilization process. If it is determined in step S43 that the required authentication level is not met ("NO" in S43), the process proceeds to step S45. In step S45, the location information acquired in step S42 is not usable in the location information utilization process. Steps S43 to S45 correspond to a usage determination section.

[0083] In the position information utilization process, the control unit 320 does not use the position information acquired in the usage-related process to be usable in the position information utilization process. Meanwhile, the position information acquired in the usage-related process to be usable in the position information utilization process is used in the position information utilization process. As an example, a billing process for billing the driver for parking the vehicle in a paid parking lot or driving the vehicle on a toll road is described below.

[0084] The position information determined in the usage determination-related process to be unusable in the position information usage process will not be scheduled for billing and will not be suspended from billing even if the position defined by the position information is included in a billing region. Meanwhile, the position information determined in the usage determination-related process to be usable in the position information usage process will be scheduled for billing and will be suspended from billing if the position defined by the position information is included in a billing region. The control unit 320 corresponds to an execution section.

[0085] According to the first embodiment, the roadside device 300, which performs a process of utilizing the position information transmitted from the in-vehicle device 200, is capable of determining whether or not to perform a position information utilization process based on the authentication level attached to the position information. For example, a settlement process requiring high position information reliability is not performed if the received authentication level is lower than the required authentication level. However, in a game-related process requiring low position information reliability, the position information can be used in the game-related process even though the position information has a low authentication level.

[0086] Consequently, in an application (APP) or a system that uses a positioning result derived from navigation messages transmitted from GPS satellites 2 used in a satellite positioning system, the positioning result can be flexibly used based on a positioning result reliability required for the application or the system. (First modification)

[0087] The first embodiment has been described assuming that the roadside device 300 is used as the positioning result receiving device. The positioning result receiving device is not limited to the roadside device 300. Alternatively, the positioning result receiving device may be a mobile device mounted, for example, in a different vehicle than the vehicle in which the in-vehicle device 200 is mounted. The position information utilization process performed by such a mobile device may be a follow-up travel process that uses the position information received from the in-vehicle device 200 to perform a follow-up travel while maintaining an appropriate inter-vehicle distance from the vehicle in which the in-vehicle device 200 is mounted.For the follow-up driving process, which requires highly reliable position information, the required authentication level should be set to a high level. (Second modification)

[0088] The first embodiment has been described with reference to a case where the location information utilization process is a billing process for charging a user for driving a vehicle on a toll road (hereinafter referred to as the road billing process). When the vehicle actually travels on a toll road, the configuration of the first embodiment cannot perform billing if the authentication level attached to the location information received from the in-vehicle device 200 mounted in the vehicle by the roadside device 300 is lower than the authentication level required for the road billing process.

[0089] To avoid the above failure, the configuration of a second modification described below may be adopted. The second modification is similar to the first embodiment except for a part of a process executed by the control unit 320 of the roadside device 300. Specifically, the second modification differs from the first modification in that the control unit 320 according to the second modification performs a road billing-related process and does not perform the usage determination-related process or the position information utilization process of the first embodiment.

[0090] The road billing related process according to the second modification will now be described with reference to the flowchart of Fig. 7. In the road settlement-related process, position information obtained when the authentication level is lower than the required authentication level is additionally stored in a successive manner, so that position information records that have been previously stored and are continuous with the position information obtained when the authentication level becomes equal to the required authentication level are also subjected to the road settlement process.

[0091] The flowchart of Fig. The process illustrated in Figure 7 may be initiated when, for example, transmission data transmitted from the in-vehicle device 200 is received by the communication unit 310 at the roadside device 300. The following description is given under the assumption that the appropriate authentication level required for the roadside billing process has been determined in advance.

[0092] First, in step S61, the transmission data received by the communication unit 310 is acquired by the communication unit 310 to obtain, for example, the position information, timestamp, and authentication level included in the transmission data. Step S61 also corresponds to the positioning result reception processing section.

[0093] In step S62, a check is performed to determine whether a road billing condition is satisfied. If a position indicated by the position information acquired in step S61 is within a region scheduled for road billing, it is determined that the road billing condition is satisfied. If the position indicated by the position information acquired in step S61 is not within the region scheduled for road billing, it is determined that the road billing condition is not satisfied. If it is determined that the road billing condition is satisfied ("YES" in S62), the process proceeds to step S63. If it is determined that the road billing condition is not satisfied ("NO" in S62), the process ends.

[0094] In step S63, a check is performed to determine whether the authentication level acquired in step S61 equals the authentication level required for the road billing process. If it is determined that the required authentication level is reached ("YES" in S63), the location information acquired in step S61 is treated as a target for the road billing process, and the process proceeds to step S73. If it is determined that the required authentication level is not reached ("NO" in S63), the location information acquired in step S61 is temporarily excluded from the road billing process, and the process proceeds to step S64. Step S63 corresponds to the usage determination section.

[0095] In step S64, a notification process is performed to notify the user of the possibility that the position information may be later handled as a billing target. In the notification process, for example, information containing an instruction to notify the user of the possibility that the position information may be later handled as a billing target is transmitted to the in-vehicle device 200 via the communication unit 310. The in-vehicle device 200 then uses a display device (not shown) or an audio output device (not shown) to notify the user of the possibility that the position information may be later handled as a billing target. Step S64 corresponds to a notification processing section.

[0096] With the configuration described above, the user can recognize the possibility that the position information can be handled later as a billing target, even if the received authentication level is currently lower than the required authentication level and the position information is not currently handled as a target for road billing. As a result, even if the authentication level increases to the required authentication level in the future, so that the travel section not scheduled for road billing becomes a target for road billing, such a change will not be an unexpected result for the user. In another example, step S64 may be omitted.

[0097] In step S65, the position information and other data acquired in step S61 are stored in an electrically rewritable memory in the control unit 320, such as a RAM or an EEPROM. Step S65 corresponds to a storage processing section.

[0098] In step S66, a check is performed to determine whether new transmission data is received from the in-vehicle device 200. If new transmission data is received ("YES" in S66), the newly received data, such as the position information, timestamp, and authentication level, is acquired, and the process proceeds to step S67. If no new transmission data is received ("NO" in S66), step S66 is repeated.

[0099] In step S67, a check is performed to determine whether the road settlement condition is not met. If it is determined that the road settlement condition is not met ("YES" in S67), the process is terminated. If it is determined that the road settlement condition is still met ("NO" in S67), the process proceeds to step S68.

[0100] In step S68, a check is performed to determine whether the authentication level acquired in step S66 equals the authentication level required for the road billing process. If it is determined that the required authentication level is reached ("YES" in S68), the position information last acquired in step S66 is treated as a target for the road billing process, and the process proceeds to step S69. If it is determined that the required authentication level is not reached ("NO" in S68), the position information last acquired in step S66 is temporarily excluded from the target of the road billing process, and the process returns to step S65. In step S65, the position information and other data acquired in step S66 are stored in the memory, and the process is repeated.Step S68 also corresponds to the usage determination section.

[0101] In step S69, a check is performed to determine whether the position information to which the authentication level acquired in step S66 is attached is continuous with the previous position information records stored in step S65. If continuity between the two is determined, an error between a position estimated from the previous position information and a position indicated by the position information to which the authentication level acquired in step S66 is attached can be determined to be greater than a threshold value. The threshold value can be defined in advance as an appropriate value.

[0102] The estimated position is a position estimated from the position information and other data successively stored in step S65. When a vehicle speed and a traveling direction are acquired from the in-vehicle device 200 in addition to the position information, the estimated position at a time indicated by the timestamp for the position information to which the authentication level acquired in step S66 is attached can be obtained by estimating the previous position information and the vehicle speed and traveling direction.As mentioned earlier, even if the vehicle speed and the traveling direction are not acquired from the in-vehicle device 200, the vehicle speed and the traveling direction can be calculated from the position information at multiple points successively stored in step S65 to estimate the position based on the position information.

[0103] In step S70, a check is performed to determine whether there is continuity. If it is determined that there is continuity ("YES" in S70), the process proceeds to step S71, and the previous position information stored in step S65 is also handled as a target for the road accounting process. If it is determined that there is no continuity ("NO" in S70), the process proceeds to step S72, and the previous position information stored in step S65 is excluded from the target of the road accounting process. Step S70 corresponds to a continuity determination section.

[0104] As in Fig. 8A, when the position information (see a black circle marked with HV in Fig. 8A), to which the authentication level acquired in step S66 is attached, continuously with the position information records successively stored in step S65 (see the white circles in Fig. 8A), the previous position information records successively stored in step S65 are also handled as targets for the road settlement process because such position information is considered to be highly reliable.

[0105] As in Fig. 8B, when the position information (see a black circle marked with HV in Fig. 8B), to which the authentication level acquired in step S66 is attached, discontinuous with or deviating from the position information records (see white circles in Fig. 8B) which have been successively stored in step S65, the previous position information records successively stored in step S65 are excluded from the road accounting process because such position information is not considered to be highly reliable.

[0106] After completion of step S71 or step S72, the process proceeds to step S73. In step S73, a check is performed to determine whether new transmission data is received from the in-vehicle device 200. If new transmission data is received ("YES" in S73), the newly received data, such as the position information, timestamp, and authentication level, is acquired, and the process proceeds to step S74. If no new transmission data is received ("NO" in S73), step S73 is repeated.

[0107] In step S74, a check is performed to determine whether the road settlement condition is not met. If it is determined that the road settlement condition is not met ("YES" in S74), the process proceeds to step S75. If it is determined that the road settlement condition is still met ("NO" in S74), the process returns to step S73 to repeat steps S73 and subsequent steps.

[0108] In step S75, a billing process is performed based on a section of a toll road traveled by the vehicle in which the in-vehicle device 200 is mounted. After completion of step S75, the road billing-related process is terminated. Step S75 corresponds to the execution section. If the received authentication level remains equal to or higher than the required authentication level during the time interval from a time point at which the road billing condition is determined to be satisfied to a time point at which the road billing condition is determined to be not satisfied, a billing process is performed for a section corresponding to the time interval from the time point at which the road billing condition is determined to be satisfied to the time point at which the road billing condition is determined to be not satisfied.

[0109] Further, when the received authentication level is lower than the required authentication level for a time period during the time interval from the time at which the road billing condition is determined to be satisfied to the time at which the road billing condition is determined to be not satisfied, and the time period included in the time interval is selected as a target for the road billing process in step S71, a billing process is also performed for the section corresponding to the time interval from the time at which the road billing condition is determined to be satisfied to the time at which the road billing condition is determined to be not satisfied.

[0110] If the received authentication level is lower than the required authentication level for a time period during the time interval from the time at which the road billing condition is determined to be satisfied to the time at which the road billing condition is determined not to be satisfied, and the time period included in the time interval is excluded from the road billing process in step S72, the road billing process is performed for a remaining section by excluding a section corresponding to the time period during which the received authentication level is lower than the required authentication level from a section corresponding to the time interval from the time at which the road billing condition is determined to be satisfied to the time at which the road billing condition is determined not to be satisfied,is received.,

[0111] With the above design, it is possible to reduce the failure to bill when the vehicle actually travels on a toll road. (Third modification)

[0112] The first embodiment has been described with reference to a case where the location information utilization process is a billing process (hereinafter referred to as the parking billing process) for billing a user for parking a vehicle in a paid parking space. However, even if the vehicle is actually parked in a paid parking space, the configuration of the first embodiment fails to perform billing if the authentication level attached to the location information received by the roadside device 300 from the in-vehicle device 200 mounted in the vehicle is lower than the authentication level required for the parking billing process.

[0113] To avoid the above omission, the configuration of a third modification described below may be adopted. The third modification is similar to the first embodiment except that part of a process executed by the control unit 320 of the roadside device 300 is different from the first embodiment. Specifically, the third modification differs from the first embodiment in that the control unit 320 according to the third modification executes a parking billing-related process and does not execute the usage determination-related process or the position information utilization process described in the first embodiment.

[0114] Furthermore, in the third modification, the control unit 220 of the in-vehicle device 200 continuously performs the above-described authentication-related process even when parking of the host vehicle is detected. The control unit 220 may be adapted to detect parking of the host vehicle when, for example, a parking brake is on, ignition power is off, or the successively measured current position remains unchanged for a predetermined period of time.

[0115] The parking billing-related process according to the third modification will now be described with reference to the flowchart of Fig. 9. In the parking billing-related process, position information obtained when the authentication level is lower than the required authentication level is successively stored, so that previously obtained position information that is continuous with the position information obtained when the authentication level becomes equal to the required authentication level is also handled as a target for the parking billing-related process.

[0116] The flowchart of Fig. The process illustrated in Figure 9 can be initiated when, for example, transmission data transmitted from the in-vehicle device 200 is received by the communication unit 310 of the roadside device 300. The following description is given assuming that the appropriate authentication level required for the parking billing process has been determined in advance.

[0117] First, in step S81, the position information, the time stamp, the authentication level, and other data included in the transmission data received by the communication unit 310 are acquired, as in the case of step S61 described above. Step S81 also corresponds to the positioning result reception processing section.

[0118] In step S82, a check is performed to determine whether the vehicle in which the in-vehicle device 200 is mounted is parked. When the vehicle speed is acquired in addition to the position information from the in-vehicle device 200, vehicle parking can be determined by checking whether the vehicle speed decreases to approximately zero. Alternatively, vehicle parking can be determined by checking whether the current position, as indicated by the successively acquired position information, remains unchanged for a predetermined period of time. Step S82 corresponds to a parking determination section.

[0119] In step S83, a check is performed to determine whether a parking billing condition is met. If a position indicated by the position information acquired in step S81 is within a parking billing region, it is determined that the parking billing condition is met. If the position indicated by the position information acquired in step S81 is not within the parking billing region, it is determined that the parking billing condition is not met. If it is determined that the parking billing condition is met ("YES" in S83), the process proceeds to step S84. If it is determined that the parking billing condition is not met ("NO" in S83), the process ends.

[0120] In step S84, a check is performed to determine whether the authentication level acquired in step S81 equals the authentication level required for the parking settlement process. If it is determined that the required authentication level is reached ("YES" in S84), the location information acquired in step S81 is treated as a target for the parking settlement process, and the process proceeds to step S94. If it is determined that the required authentication level is not reached ("NO" in S84), the location information acquired in step S81 is temporarily excluded from the parking settlement process, and the process proceeds to step S85. Step S84 corresponds to the usage determination section.

[0121] In step S85, a notification process is performed to notify the user of the possibility that the position information may later be handled as a target for billing, as is the case with step S64 described above. Step S85 corresponds to the notification processing section.

[0122] With the above configuration, even if the authentication level at the current time is lower than the required authentication level and the location information is not handled as a target for parking billing, the user can recognize the possibility that the location information may be handled as a billing target later. As a result, even if the authentication level will be at the required authentication level in the future, so that a time period not scheduled for parking billing will become a target for parking billing, such a change will not be an unexpected result for the user. In another example, step S85 may be omitted.

[0123] In step S86, the position information and other data acquired in step S81 are stored in an electrically rewritable memory in the control unit 320, such as a RAM or an EEPROM. Step S86 corresponds to the storage processing section.

[0124] In step S87, a check is performed to determine whether new transmission data is received from the in-vehicle device 200. If new transmission data is received ("YES" in S87), the newly received data, such as the position information, timestamp, and authentication level, is acquired, and the process proceeds to step S88. If no new transmission data is received ("NO" in S87), step S87 is repeated.

[0125] In step S88, a check is performed to determine whether the parking settlement condition is not met. If it is determined that the parking settlement condition is not met ("YES" in S88), the process is terminated. If it is determined that the road settlement condition is still met ("NO" in S88), the process proceeds to step S89.

[0126] In step S89, a check is performed to determine whether the authentication level acquired in step S87 equals the authentication level required for the parking settlement process. If it is determined that the required authentication level is met ("YES" in S89), the location information last acquired in S87 is treated as a target for the parking settlement process, and the process proceeds to step S90. If it is determined that the required authentication level is not met ("NO" in S89), the location information last acquired in step S87 is temporarily excluded from the parking settlement process, and the process returns to step S86. In the returned step S86, the location information and other data acquired in step S87 are stored in the memory, and the process is repeated.Step S89 also corresponds to the usage determination section.

[0127] In step S90, a check is performed to determine whether the position information to which the authentication level acquired in step S87 is attached is continuous with the previous position information stored in step S86. Whether the two position information are continuous with each other is determined by comparing an error between a position indicated by the previous position information and a position indicated by the position information to which the authentication level acquired in step S87 is attached with a threshold value.As an example, the two position information are determined to be continuous when the error between the position indicated by the previous position information initially stored in the memory in step S86 and the position indicated by the position information to which the authentication level acquired in step S87 is attached is equal to or less than the threshold value. The threshold value can be defined in advance as an appropriate value.

[0128] In step S91, a check is performed to determine whether there is continuity. If it is determined that there is continuity ("YES" in S91), the process proceeds to step S92, and the previous position information stored in step S86 is also handled as a target for the parking settlement process. If it is determined that there is no continuity ("NO" in S91), the process proceeds to step S93, and the previous position information stored in step S86 is excluded from the target of the parking settlement process. Step S91 corresponds to the continuity determination section.

[0129] After completion of step S92 or S93, the process proceeds to step S94. In step S94, a check is performed to determine whether new transmission data is received from the in-vehicle device 200. If new transmission data is received ("YES" in S94), the newly received data, such as the position information, timestamp, and authentication level, is acquired, and the process proceeds to step S95. If no new transmission data is received ("NO" in S94), step S94 is repeated.

[0130] In step S95, a check is performed to determine whether the parking settlement condition is not met. If it is determined that the parking settlement condition is not met ("YES" in S95), the process proceeds to step S96. If it is determined that the parking settlement condition is still met ("NO" in S95), the processing returns to step S94 to repeat steps S94 and subsequent steps.

[0131] In step S96, a billing process is performed based on an elapsed time after the vehicle in which the in-vehicle device 200 is mounted has been parked. After completion of step S96, the parking billing-related process is terminated. Step S96 corresponds to the execution section. If the received authentication level remains equal to or higher than the required authentication level during the time interval from the time the parking billing condition is determined to be satisfied to the time the parking billing condition is determined to be unsatisfied, the billing process is performed based on a time interval from the time the parking billing condition is determined to be satisfied to the time the parking billing condition is determined to be unsatisfied.The time interval can be calculated using the timestamp of the position information.

[0132] If the required authentication level is not continuously achieved during the time interval from the time at which the parking billing condition is determined to be satisfied until the time at which the parking billing condition is determined not to be satisfied, and the time interval between such times is selected in step S92 as a target for the parking billing process, a billing process is further also performed based on the time interval from the time at which the parking billing condition is determined to be satisfied until the time at which the parking billing condition is determined not to be satisfied.

[0133] Assume that the received authentication level becomes lower than the required authentication level for a period of time during the time interval from the time the parking settlement condition is determined to be met to the time the parking settlement condition is determined not to be met. In this case, the time period during which the received authentication level becomes lower than the required authentication level is excluded from the parking settlement process in step S93.Thus, the billing process is performed for a remaining time segment obtained by excluding the time period during which the received authentication level is lower than the required authentication level from the time interval from the time at which the parking billing condition is determined to be satisfied to the time at which the parking billing condition is determined not to be satisfied.

[0134] With the above design, it is possible to reduce the failure to bill when the vehicle is actually parked in a paid parking space. (Second embodiment)

[0135] While the first embodiment of the present invention has been described above, the present invention is not limited to the first embodiment. A second embodiment, which will be described below, is also included in the technical scope of the present invention. The second embodiment will now be described with reference to the accompanying drawings. For convenience of explanation, elements having the same function as the elements shown in the drawings used to describe the above embodiment will be denoted by the same reference numerals as their counterparts and will not be described redundantly.

[0136] As in Fig. As shown in FIG. 10, a positioning result utilization system 1a according to the second embodiment is similar to the positioning result utilization system 1 according to the first embodiment, except that the positioning result utilization system 1a according to the second embodiment includes a position information utilization device 400. The position information utilization device 400 functions as the positioning result reception device provided by the roadside device 300 in the first embodiment. In the present embodiment, the position information utilization device 400 is used for a vehicle in which the in-vehicle device 200 is mounted. In the present embodiment, the position information utilization device 400 corresponds to the positioning result reception device.

[0137] The location information utilization device 400 may be, for example, an in-vehicle navigation device or a mobile terminal used for a vehicle. The mobile terminal provided as the location information utilization device 400 may, for example, have a GPS function, but may not perform the authentication-related process described above.

[0138] As in Fig. As shown in Figure 11, the position information utilization device 400 is connected to the in-vehicle device 200, for example, via an in-vehicle LAN, and includes a communication unit 410 and a control unit 420. The communication unit 410 communicates with the communication unit 210 in the in-vehicle device 200. The following description is given assuming that the in-vehicle device 200 communicates with the position information utilization device 400 via the in-vehicle LAN. In another example, the in-vehicle device 200 may communicate wirelessly with the position information utilization device 400.

[0139] The control unit 420 is provided by a computer including a CPU, a ROM, and a RAM, and controls the communication unit 410. Furthermore, the control unit 420 performs processes similar to the usage determination-related process described in the first embodiment, the road billing process described in the second modification, and the parking billing process described in the third modification by allowing the CPU to utilize a temporary storage function of the RAM and execute programs stored in the ROM. Thus, the control unit 420 corresponds to the positioning result reception processing section, the usage determination section, the execution section, the storage processing section, the continuity determination section, and the parking determination section.

[0140] Whether a host vehicle is parked can be determined by control unit 420 based on a parking brake or ignition energy signal. The parking brake or ignition energy signal can be acquired through the in-vehicle LAN.

[0141] As in the first embodiment, the second embodiment allows the position information utilization device 400, which performs a process of using the position information transmitted from the in-vehicle device 200, to determine whether or not to perform the process using the position information based on the authentication level attached to the position information. Therefore, in an application or system that uses a positioning result derived from the navigation messages transmitted from GPS satellites 2 used in a satellite positioning system, the positioning result can be flexibly utilized based on the positioning result reliability required for the application or system. (Third embodiment)

[0142] The present invention is not limited to the first and second embodiments. A third embodiment, which will be described below, is also included within the technical scope of the present invention. The third embodiment will now be described with reference to the accompanying drawings. For convenience of explanation, elements having the same function as the elements shown in the drawings used to describe the above embodiments will be denoted by the same reference numerals as their counterparts and will not be described redundantly.

[0143] As in Fig. As shown in Figure 12, a positioning result utilization system 1b according to the third embodiment is similar to the positioning result utilization system 1 according to the first embodiment, except that the positioning result utilization system 1b according to the third embodiment includes a mobile terminal 500 and does not include the in-vehicle device 200, the roadside device 300, or the position information utilization device 400. The mobile terminal 500 acts as a substitute for the in-vehicle device 200, the roadside device 300, and the position information utilization device 400.

[0144] As is the case with the in-vehicle device 200, the mobile terminal 500 communicates with the authentication center 120 to perform the authentication-related process described above. Furthermore, as is the case with the in-vehicle device 200, the mobile terminal 500 uses the navigation messages received from a plurality of GPS satellites 2 to measure its current position and calculate the above-described authentication level. Furthermore, the mobile terminal 500 uses the measured current position to execute applications that provide predetermined services. The applications include an application that performs the above-described road billing process or the above-described parking billing process, or a game that uses the position information.

[0145] For example, a smartphone or other multifunctional mobile phone can be used as the mobile terminal 500. A navigation device or other in-vehicle device that has the GPS function and performs the authentication-related process described above can be used instead of the mobile terminal 500.

[0146] As in Fig. As shown in Figure 13, the mobile terminal 500 includes a communication unit 510, a control unit 520, and a satellite receiver 530. The navigation message broadcast by the QZS 3 is received by a receiving unit 511 included in the communication unit 510 of the mobile terminal 500.

[0147] The communication unit 510 includes the receiving unit 511 and a transmitting unit 512 and performs the same function as the above-described communication unit 210 of the in-vehicle device 200. The satellite receiver 530 performs the same function as the above-described satellite receiver 230.

[0148] The control unit 520 is provided by a computer including a CPU, a ROM, and a RAM, and controls the communication unit 510 and the satellite receiver 530. Furthermore, the control unit 520 performs an authentication-related process similar to the authentication-related process described in the first embodiment and a position information utilization-related process described in Fig. 14, by allowing the CPU to utilize a temporary storage function of the RAM and execute programs stored in the ROM. In the authentication-related process executed by the control unit 520, step S1 corresponds to the positioning section, step S5 corresponds to the authentication information acquisition section, and steps S9 to S11 correspond to the authentication section.

[0149] The position information usage-related process is now described with reference to the flowchart of Fig. 14. The position information utilization-related process is performed by the control unit 520 of the mobile terminal 500 to use the measured current position. The position information utilization-related process is performed to calculate the authentication level, which is the number or ratio of authenticated GPS satellites 2 used to measure the current position, and determines whether or not to use the acquired current position in a position utilization application that uses the current position based on the calculated authentication level.

[0150] The flowchart of Fig. The process illustrated in Figure 14 can be initiated when the position utilization application is in an activated state and the current position of the mobile terminal 500 is measured by the control unit 520 of the mobile terminal 500. The current position of the mobile terminal 500 is measured based on the navigation messages contained in GPS radio waves received from three or more GPS satellites 2.

[0151] In the present embodiment, an authentication-related process similar to the process described in the first embodiment is executed, and this authentication-related process is carried out in parallel with the process shown in the flowchart of Fig. 14 is executed. Even if only a part of the navigation messages used for positioning is authenticated, the process described in the flowchart of Fig. The process shown in Figure 14 can be started.

[0152] First, in step S101, the current position of the mobile terminal 500, which is measured based on the navigation messages contained in the GPS radio waves received from three or more GPS satellites 2, is acquired. The acquired current position is then stored in an electrically rewritable memory in the control unit 520, such as a RAM or an EEPROM. When the acquired current position is to be stored in the memory, a timestamp, which is information indicative of a time at which the current position was measured, is appended to the acquired current position.

[0153] In step S102, the authentication level is calculated, as in step S22 described above. The authentication level is the ratio of the number of GPS satellites 2 currently authenticated in the authentication-related process to the number of GPS satellites 2 used to measure the acquired current position. Step S102 corresponds to the authentication level calculation section. The authentication level can alternatively be the number of authenticated GPS satellites 2.

[0154] In step S103, the required authentication level required for the currently operating location-utilization application is determined. For example, the required authentication level can be determined by referring to a predefined relationship between different location-utilization applications and corresponding required authentication levels. As is the case with step S41 described above, step S103 is performed under the assumption that the higher the position information reliability required for the location-utilization application, the higher the required authentication level. If the required authentication level is a predetermined fixed value, step S103 can be omitted.

[0155] In step S104, a check is performed to determine whether the authentication level calculated in step S102 is equal to the required authentication level determined in step S103, as is the case with step S102 described above. If it is determined that the required authentication level is met ("YES" in S104), the process proceeds to step S105. In step S105, the location information acquired in step S101 is handled as a target for the location utilization application. If it is determined that the required authentication level is not met ("NO" in S104), the process proceeds to step S106. In step S106, the location information acquired in step S101 is not handled as a target for the location utilization application. Steps S104 to S106 correspond to the usage determination section.

[0156] If it is determined in the location information usage-related process that the location information is not handled as a target for the location usage application, the control unit 520 does not use the location information for the location usage application. If it is determined in the location information usage-related process that the location information is handled as a target for the location usage application, the control unit 520 uses the location information in the location usage application. The following description is given assuming that the location usage application performs the above-described road billing process or the above-described parking billing process.

[0157] If the location information is determined not to be handled as a target for the location usage application in the location information usage-related process, the location indicated by the location information will not be set as a target for billing and will not be subjected to billing even if it is included in a billing-specified region. If the location information is determined not to be handled as a target for the location usage application in the location information usage-related process, the location indicated by the location information will be set for billing and will be subjected to billing if it is included in a billing-specified region. The control unit 520 corresponds to the execution section.

[0158] According to the third embodiment, the mobile terminal 500 determines whether or not to execute the position-utilization application based on the authentication level of a navigation message from a GPS satellite 2 used for measuring the current position. Therefore, a billing process requiring high position information reliability will not be performed if the calculated authentication level is low. However, a process for, for example, a game that requires low position information reliability can be performed even if the authentication level is low.

[0159] Consequently, in an application or system that uses a positioning result derived from navigation messages transmitted from GPS satellites 2 used in a satellite positioning system, the positioning result can be flexibly used based on a positioning result reliability required for the application or system.

[0160] The mobile terminal 500 does not always have to be mounted in and used for a vehicle, but can be carried by a person. When the mobile terminal 500 is carried by a person, the location-based application can provide a game, such as an orienteering race or a stamp collection rally, or perform a billing process by determining entry to a theme park or the use of an amusement ride in the theme park based on the current location. (Fourth modification)

[0161] The third embodiment has been described with reference to a case where the location-utilization application provides a road billing process in which a user is billed for driving a vehicle on a toll road. However, even if the vehicle actually drives on a toll road, the configuration of the third embodiment may fail to perform billing if the authentication level is lower than the authentication level required for the road billing process.

[0162] To avoid the above-described oversight, an embodiment of a fourth modification described below may be adopted. The fourth modification is similar to the second modification except that a process according to the fourth modification is performed by the control unit 520 of the mobile terminal 500.

[0163] The road billing related process according to the fourth modification will now be explained with reference to the flowchart of Fig. 15. The flowchart in Fig. The process illustrated in Figure 15 may be initiated when, for example, an application for the road billing-related process is in an activated state and the current position of the mobile terminal 500 is measured by the control unit 520 of the mobile terminal 500. The current position of the mobile terminal 500 is measured based on the navigation messages contained in GPS radio waves received from three or more GPS satellites 2.

[0164] First, in step S121, the current position of the mobile terminal 500, which is measured based on the navigation messages contained in the GPS radio waves received from three or more GPS satellites 2, is acquired. A timestamp is appended to the acquired current position, and the position information is stored in the memory along with the timestamp.

[0165] Steps S122 to S135 are similar to steps S62 to S75 of the second modification. The fourth modification differs from the second modification in that a check is performed in steps S126 and S133 to determine whether new positioning results are acquired, and in step S124, a display device (not shown) or an audio output device (not shown) included in the mobile terminal 500 notifies the user of the possibility that the positioning information may later be handled as a billing target. Thus, steps S123 and S128 correspond to the usage determination section, step S124 corresponds to the notification processing section, step S125 corresponds to the storage processing section, step S129 corresponds to the continuity determination section, and step S135 corresponds to the execution section. In another example, step S124 may be omitted.

[0166] With the above configuration, it is possible to reduce the failure to perform billing when the vehicle actually drives on a toll road. (Fifth Modification)

[0167] The third embodiment has been described with reference to a case where the location-utilization application provides a parking billing process in which a user is billed for parking a vehicle in a paid parking space. However, even if the vehicle is actually parked in a paid parking space, the configuration of the third embodiment may fail to perform billing if the authentication level is lower than the authentication level required for the parking billing process.

[0168] To avoid the above omission, the configuration of a fifth modification described below may be adopted. The fifth modification is similar to the third modification except that a process according to the fifth modification is performed by the control unit 520 of the mobile terminal 500.

[0169] The parking billing-related process according to the fifth modification will now be described with reference to the flowchart of Fig. 16. The flowchart in Fig. The process illustrated in Fig. 16 may be initiated when, for example, an application for the parking billing-related process is in an activated state and the current position of the mobile terminal 500 is measured based on the navigation messages included in GPS radio waves received from three or more GPS satellites 2 by the control unit 520 of the mobile terminal 500.

[0170] First, in step S141, the current position of the mobile terminal 500, which is measured based on the navigation messages contained in the GPS radio waves received from three or more GPS satellites 2, is acquired. A timestamp is appended to the acquired current position, and the position information is stored in the memory along with the timestamp.

[0171] Steps S142 to S155 are similar to steps S82 to S96 of the third modification. The fifth modification differs from the third modification in that a check is performed in steps S147 and S154 to determine whether new positioning results are acquired, and in step S145, a display device (not shown) or an audio output device (not shown) included in the mobile terminal 500 notifies the user of the possibility that the position information will later be handled as a billing target. Thus, step S142 corresponds to the parking determination section, steps S144 and S149 correspond to the usage determination section, step S145 corresponds to the notification processing section, step S146 corresponds to the storage processing section, step S150 corresponds to the continuity determination section, and step S156 corresponds to the execution section.In another example, step S145 may be omitted.

[0172] With the above design, it is possible to reduce the failure to perform billing when the vehicle is actually parked in a paid parking space.

[0173] It should be noted that in the present invention, a flowchart or the processing of the flowchart includes sections (also referred to as steps), each of which is represented, for example, as S1. Furthermore, each section may be divided into multiple subsections, while multiple sections may be combined into a single section. Furthermore, each of the thus-configured sections may also be referred to as a circuit, a device, a module, or a means.

[0174] Any or any combination of sections explained above may be achieved by (i) a software section in combination with a hardware unit (e.g., a computer) or (ii) a hardware section including or not including a function of a device concerned, further the hardware section (e.g., an integrated circuit, a hard-wired logic circuit) may be formed in a microcomputer. (Other embodiments)

[0175] The above embodiments have been described with reference to a case in which positioning is performed using only the navigation messages received from the GPS satellites 2. In an alternative embodiment, the navigation messages received from the QZS 3 can be used for positioning purposes. In such an alternative embodiment, the navigation messages received from the QZS 3 can be authenticated in the same way as the navigation messages received from the GPS satellites 2.

[0176] In an exemplary alternative embodiment, a RAND message may be generated by the monitoring station 110 from a navigation message received from the QZS 3 to direct the authentication center 120 to generate parity data from the RAND message. The generated parity data is then transmitted to the master control station 130 to direct the master control station 130 to transmit the parity data to the QZS 3. The QZS 3 broadcasts a navigation message containing the parity data to the ground.

[0177] The in-vehicle device 200 may generate a RAND message from the navigation message received from the QZS 3 and generate comparative parity data from the RAND message and the H-matrix acquired from the authentication center 120. The generated comparative parity data is then compared with the parity data received from the QZS 3 to perform authentication.

[0178] The authentication methods described in connection with the preceding embodiments are only examples. It is obvious that an alternative authentication method may be used.

[0179] While the invention has been described with reference to preferred embodiments thereof, it should be understood that the invention is not limited to the preferred embodiments and configurations. The invention is intended to cover various modifications and equivalent arrangements. Furthermore, in addition to the various combinations and configurations which are preferred, other combinations and configurations including more, fewer, or only a single element are also within the spirit and scope of the invention.

Claims

[1] Device with a positioning function comprising: a satellite receiver (230) which receives signals from artificial satellites used in a satellite positioning system; a positioning section (S1) which measures a position of a host device based on the signals received by the satellite receiver from the artificial satellites; an authentication information acquisition section (S5) which acquires authentication information from an authentication center (120) arranged outside the host device, the authentication information being used to authenticate whether the signals from the artificial satellites are legitimate signals; an authentication section (S9, S10, S11) which authenticates, based on the authentication information, whether the signals received by the satellite receiver are the legitimate signals from the artificial satellites; an authentication level calculation section (S22) which calculates an authentication level based on at least one of a set of artificial satellites authenticated by the authentication section or a ratio of the artificial satellites authenticated by the authentication section to the artificial satellites used for positioning the host device by the positioning section; and a positioning result transmission processing section (S24) which successively transmits a positioning result measured by the positioning section to a device other than the host device, wherein the positioning result transmission processing section appends the authentication level calculated by the authentication level calculation section to the positioning result before transmitting the positioning result. [2] A device having a positioning function according to claim 1, wherein the device is used with a positioning function for a moving body, and the positioning result transmission processing section transmits the positioning result and the authentication level to the different device arranged outside the movable body. [3] A device having a positioning function according to claim 1, wherein the device is used with a positioning function for a moving body, and the positioning result transmission processing section transmits the positioning result and the authentication level to the different device arranged in the movable body. [4] Device with a positioning function comprising: a satellite receiver (530) which receives signals from artificial satellites used for a satellite positioning system; a positioning section (S1) which measures a position of a host device based on the signals received by the satellite receiver from the artificial satellites; an authentication information acquisition section (S5) that acquires authentication information from an authentication center located outside the host device, the authentication information being used to authenticate whether the signals from the artificial satellites are legitimate signals; an authentication section (S9, S10, S11) which authenticates, based on the authentication information, whether the signals received by the satellite receiver are legitimate signals from the artificial satellites; an authentication level calculation section (S102) that calculates an authentication level based on at least one of a set of artificial satellites authenticated by the authentication section or a ratio of the artificial satellites authenticated by the authentication section to the artificial satellites used for positioning the host device by the positioning section; an execution section (S135, S156) which executes a positioning result utilization process, wherein the positioning result utilization process is a process which uses a positioning result measured by the positioning section; and a usage determination section (S104, S105, S106, S123, S128, S144, S149) that determines whether to use the positioning result measured by the positioning section in the positioning result usage process based on the authentication level calculated by the authentication level calculation section. [5] A device having a positioning function according to claim 4, wherein, when a reliability of the positioning result required for the positioning result utilization process increases, the utilization determination section increases a reference level with which the authentication level is compared to allow use of the positioning result in the positioning result utilization process, and the positioning result utilization process is executed by the execution section and the positioning result is measured by the positioning section. [6] A device with a positioning function according to claim 4 or 5, wherein the device with a positioning function is used for a movable body, the device with a positioning function further comprising: a storage processing section (S125, S146) which successively stores, under a condition that an activation condition of the positioning result utilization process is satisfied and the authentication level calculated by the authentication level calculation section is lower than an authentication level required for the positioning result utilization process, the positioning results measured by the positioning section from a time point at which the activation condition of the positioning result utilization process is satisfied; and a continuity determination section (S129, S150) which, under a condition that the authentication level calculated by the authentication level calculation section becomes equal to the authentication level required for the positioning result utilization process, determines whether the positioning result obtained when the authentication level calculated by the authentication level calculation section becomes equal to the authentication level required for the positioning result utilization process is continuous with the positioning results successively stored by the storage processing section, wherein, when the continuity determination section determines existence of continuity, the execution section additionally uses the positioning results successively stored by the storage processing section in the positioning result utilization process. [7] A device with a positioning function according to claim 6, wherein the movable body for which the device with a positioning function is used is a vehicle, the device with a positioning function further comprising: a parking determination section (S142) which determines whether the vehicle is parked, wherein, if the authentication level calculated by the authentication level calculation section is lower than the authentication level required for the positioning result utilization process, the authentication section repeatedly authenticates the signals from the artificial signals even if the parking determination section determines that the vehicle is parked, when the parking determination section determines that the vehicle is parked, the activation condition of the positioning result utilization process is met, and the authentication level calculated by the authentication level calculation section is lower than the authentication level required for the positioning result utilization process, the storage processing section successively stores the positioning results measured by the positioning section from the time at which the activation condition of the positioning result utilization process is met, and when the authentication level calculated by the authentication level calculation section becomes equal to the authentication level required for the positioning result utilization process, the continuity determination section determines whether a difference between the positioning result obtained when the authentication level calculated by the authentication level calculation section becomes equal to the authentication level required for the positioning result utilization process and the positioning result stored in advance by the storage processing section is smaller than a predetermined value for determining the existence of continuity. [8] Device with a positioning function according to claim 6 or 7, wherein the positioning result utilization process is a billing process that bills a user when the movable body is placed within a predetermined region, If an activation condition of the billing process is met and the authentication level calculated by the authentication level calculation section is lower than an authentication level required for the billing process, the execution section does not execute the billing process until the authentication level calculated by the authentication level calculation section becomes equal to the authentication level required for the billing process, when the authentication level calculated by the authentication level calculation process becomes equal to the authentication level required for the billing process and the continuity determination section determines the existence of continuity, the execution section additionally uses the positioning results successively stored by the storage processing section in the billing process, and the device with a positioning function further includes a notification processing section (S124, S145) which notifies the user of an opportunity for later billing when the activation condition of the billing process is met and the authentication level calculated by the authentication level calculation section is lower than the authentication level required for the billing process. [9] Positioning result receiving device comprising: a positioning result reception processing section (S42, S61, S81) that receives a positioning result transmitted from a device (200) with a positioning function, wherein the device with a positioning function authenticates whether signals received by a satellite receiver (230) are legitimate signals transmitted from artificial satellites used in a satellite positioning system, and appends to the positioning result received by the positioning result reception processing section an authentication level calculated based on at least one of a set of artificial satellites that are authenticated or a ratio of the artificial satellites that are authenticated to artificial satellites used when measuring the positioning result by the device with a positioning function; an execution section (S75, S96) which executes a positioning result utilization process, wherein the positioning result utilization process is a process which uses the positioning result received by the positioning result reception processing section; and a usage determination section (S43, S44, S45, S63, S68, S84, S89) that determines whether to use the positioning result in the positioning result usage process based on the authentication level attached to the positioning result received by the positioning result reception processing section. [10] The positioning result receiving device according to claim 9, wherein when a reliability of the positioning result required for the positioning result utilization process increases, the utilization determination section increases a reference level with which the authentication level is compared to allow utilization of the positioning result in the positioning result utilization process, and the positioning result utilization process is executed by the execution section and the positioning result is received by the positioning result reception processing section. [11] The positioning result receiving device according to claim 9 or 10, wherein the device having a positioning function is used for a moving body, and the positioning result receiving processing section receives from the device having a positioning function the positioning result to which the authentication level is attached, the positioning result receiving device further comprising: a storage processing section (S65, S86) which successively stores the positioning results received after the activation condition of the positioning result utilization process is satisfied, under a condition that an activation condition of the positioning result utilization process is satisfied and the authentication level received by the positioning result reception processing section is lower than the authentication level required for the positioning result utilization process; and a continuity determination section (S70, S91) which, under a condition that the authentication level received by the positioning result reception processing section becomes equal to the authentication level required for the positioning result utilization process, determines whether the positioning result to which the authentication level is attached is continuous with the positioning results that have been successively stored by the storage processing section, wherein, when the continuity determination section determines existence of continuity, the execution section additionally uses the positioning results successively stored by the storage processing section in the positioning result utilization process. [12] The positioning result receiving device according to claim 11, wherein the device having a positioning function is used for the mobile body which is a vehicle, and the positioning result receiving processing section receives from the device having a positioning function the positioning result to which the authentication level is attached, the positioning result receiving device further comprising: a parking determination section (S82) which determines whether the vehicle is parked, wherein, when the parking determination section determines that the vehicle is parked, the activation condition of the positioning result utilization process is satisfied, and the authentication level received by the positioning result reception processing section is lower than the authentication level required for the positioning result utilization process, the storage processing section successively stores the positioning results received after the activation condition of the positioning result utilization process is satisfied, and when the authentication level received by the positioning result reception processing section becomes equal to the authentication level required for the positioning result utilization process, the continuity determination section determines whether a difference between the positioning results to which the authentication level is attached and the positioning result stored in advance by the storage processing section is smaller than a predetermined value for determining the existence of continuity. [13] A positioning result receiving device according to claim 11 or 12, wherein the positioning result utilization process is a billing process that bills a user when the movable body is placed within a predetermined region, If an activation condition of the billing process is met and the authentication level received by the positioning result reception processing section is lower than the authentication level required for the billing process, the execution section does not execute the billing process until the authentication level received by the positioning result reception processing section becomes equal to the authentication level required for the billing process, when the authentication level received by the positioning result reception processing section becomes equal to the authentication level required for the billing process and the continuity determination section determines the existence of continuity, the execution section additionally uses the positioning results successively stored by the storage processing section in the billing process, and the positioning result receiving device further includes a notification processing section (S64, S85) which notifies the user of an opportunity for later billing when the activation condition of the billing process is met and the authentication level received by the positioning result receiving processing section is lower than the authentication level required for the billing process. [14] Positioning result utilization system comprising: a device (200) with a positioning function; and a positioning result receiving device (300, 400), the device (200) having a positioning function including: a satellite receiver (230) which receives signals from artificial satellites used in a satellite positioning system; a positioning section (S1) which measures a position of a host device based on the signals received by the satellite receiver from the artificial satellites; an authentication information acquisition section (S5) that acquires authentication information from an authentication center located outside the host device, the authentication information being used to authenticate whether the signals from the artificial satellites are legitimate signals; an authentication section (S9, S10, S11) which authenticates, based on the authentication information, whether the signals received by the satellite receiver are the legitimate signals from the artificial satellites; an authentication level calculation section (S22) which calculates an authentication level based on at least one of a set of artificial satellites authenticated by the authentication section or a ratio of the artificial satellites authenticated by the authentication section to the artificial satellites used for positioning the host device by the positioning section; and a positioning result transmission processing section (S24) which successively transmits a positioning result measured by the positioning section to a different device other than the host device, wherein the positioning result transmission processing section appends the authentication level calculated by the authentication level calculation section to the positioning result before transmission of the positioning result, and the positioning result receiving device (300, 400) includes: a positioning result reception processing section (S42, S61, S81) which receives the positioning result successively transmitted from the device (200) having a positioning function, wherein the authentication level is appended to the positioning result; an execution section (S75, S96) which executes a positioning result utilization process which uses the positioning result received by the positioning result reception processing section; and a usage determination section (S43, S44, S45, S63, S68, S84, S89) that determines whether to use the positioning result in the positioning result usage process based on the authentication level attached to the positioning result received by the positioning result reception processing section.

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