JP2016169974A - Position measurement device, position measurement method, program, and position measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance accuracy in positioning a mobile body.SOLUTION: A position measurement device includes: a satellite signal reception section for receiving a positioning signal to be transmitted from a satellite and measuring the position and distance of the satellite that has transmitted the positioning signal; a communication signal reception section for receiving a communication signal to be used for the transmission of a position information message including at least the position of a vehicle; an estimation section for estimating a distance from the vehicle that has transmitted the position information message in accordance with signal intensity when the communication signal is received; and a positioning section for measuring the position of the position measurement device itself on the basis of the position and distance of the satellite measured by the satellite signal reception section, the position of the vehicle included in the position information message, and the distance from the vehicle estimated by the estimation section. The present technique is applied to a position measurement system, for example, including the satellite, the vehicle, and the position measurement device.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a position measurement device, a position measurement method, a program, and a position measurement system, and in particular, a position measurement device, a position measurement method, a program, and a position that can further improve the positioning accuracy of a moving object. It relates to a measurement system.

  Conventionally, it has been reported that the number of deaths in traffic accidents is the largest number of pedestrians, and in order to prevent pedestrian traffic accidents, pedestrians have been detected by vehicles equipped with radar and cameras. ing. However, it has been difficult to cope with detection of pedestrians in places where the line of sight is not effective. On the other hand, in order to protect pedestrians from traffic accidents, for example, communication between pedestrians and vehicles (hereinafter referred to as inter-pedestrian communication as appropriate) is performed to notify the vehicle of pedestrian location information. When a pedestrian is in a hazardous area, it is considered to alert the driver.

  In recent years, smartphones are rapidly spreading. For example, when a pedestrian is outdoors, position information such as a GPS (Global Positioning System) module included in the smartphone can be used to calculate its own position information. However, since the GPS module uses a simple antenna and the pedestrian is close to the roadside building and the positioning signal is easily shielded, the positioning accuracy for measuring the position of the pedestrian is low.

  For this reason, research and development for improving the positioning accuracy of pedestrians are underway. For example, Patent Document 1 discloses that a mobile object with a simple configuration can be used even in a place that is susceptible to multipath waves. A position measuring device capable of acquiring an absolute position with high accuracy has been proposed.

JP 2012-52905 A

  By the way, in the situation where the positioning accuracy of the pedestrian is low as described above, there is a possibility that the driver is frequently inadvertently alerted when the position information of the pedestrian is notified to the vehicle by inter-vehicle communication. The reliability of the arousal may be significantly reduced. Therefore, in order to avoid such a possibility, it is required to improve the positioning accuracy of pedestrians.

  This indication is made in view of such a situation, and makes it possible to aim at the further improvement in the positioning accuracy of a mobile.

  A position measurement apparatus according to an aspect of the present disclosure receives a positioning signal transmitted from a satellite and used for position measurement, and receives a satellite signal that measures the position and distance of the satellite that has transmitted the positioning signal. A communication signal receiving unit that receives a communication signal used for transmitting a position information message including at least the position of the vehicle, and the position information message transmitted according to the signal strength when the communication signal is received. An estimation unit for estimating a distance from the vehicle; a position and distance of the satellite measured by the satellite signal reception unit; a position of the vehicle included in the position information message; and the vehicle estimated by the estimation unit. And a positioning unit that measures the position of the position measuring device itself based on the distance to the position measuring device.

  A position measurement method or program according to one aspect of the present disclosure receives a positioning signal transmitted from a satellite and used for position measurement, measures the position and distance of the satellite that has transmitted the positioning signal, and Receiving a communication signal used for transmitting a position information message including at least the position of the vehicle, according to the signal strength at the time of receiving the communication signal, estimating the distance from the vehicle that transmitted the position information message, Measuring the position of the position measuring device itself based on the position and distance of the satellite, the position of the vehicle included in the position information message, and the distance to the vehicle.

  A position measurement system according to an aspect of the present disclosure is a position measurement system including a satellite, a vehicle, and a position measurement device, wherein the satellite transmits a positioning signal for use in position measurement, and the vehicle Transmits a position information message including at least the position of the vehicle, and the position measurement device receives a positioning signal transmitted from the satellite and used for position measurement, and transmits the positioning signal. Measure the position and distance of the satellite, receive a communication signal used to transmit a position information message including at least the position of the vehicle, and change the position information message according to the signal strength when the communication signal is received. Estimating the distance to the transmitted vehicle, the position and distance of the satellite, the position of the vehicle included in the position information message, and the distance to the vehicle Based on, for measuring the position of the position measuring device itself.

  In one aspect of the present disclosure, a positioning signal transmitted from a satellite and used for position measurement is received, the position and distance of the satellite that transmitted the positioning signal are measured, and at least the position of the vehicle is included. A communication signal used for transmitting the position information message is received, and the distance from the vehicle that transmitted the position information message is estimated according to the signal strength when the communication signal is received. Then, the position of the position measuring device itself is measured based on the position and distance of the satellite, the position of the vehicle included in the position information message, and the distance from the vehicle.

  According to one aspect of the present disclosure, it is possible to further improve the positioning accuracy of the moving body.

It is a figure showing an example of composition of a 1st embodiment of a position measuring system to which this art is applied. It is a figure explaining a direct wave and a reflected wave. It is a figure which shows the channel state information showing the amplitude of the communication signal which passed through the several path | route, and its arrival time. It is a block diagram which shows the structural example of a position measuring device. It is a flowchart explaining the process performed in a vehicle. It is a flowchart explaining the process performed in a position measuring device. It is a figure which shows the structural example of 2nd Embodiment of the position measurement system to which this technique is applied. It is a figure which shows the structural example of 2nd Embodiment of the position measurement system to which this technique is applied. It is a flowchart explaining the process performed in an access point. It is a flowchart explaining the process performed in a vehicle. It is a flowchart explaining the process performed in a server apparatus. It is a 1st flowchart explaining the process performed in a position measuring device. It is a 2nd flowchart explaining the process performed in a position measuring device. It is a 1st flowchart explaining the modification of the process performed in a position measuring device. It is a 2nd flowchart explaining the modification of the process performed in a position measuring device. It is a flowchart explaining the modification of the process performed in a server apparatus. And FIG. 18 is a block diagram illustrating a configuration example of an embodiment of a computer to which the present technology is applied.

  Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a position measurement system to which the present technology is applied.

  In the position measurement system 11 of FIG. 1, a position measurement device 12 carried by a pedestrian communicates with a plurality of vehicles 14 in addition to receiving positioning signals from a plurality of GPS satellites 13. The position can be measured with higher accuracy. In the example of FIG. 1, the position measurement device 12 receives positioning signals from four GPS satellites 13-1 to 13-4 and communicates with seven vehicles 14-1 to 14-7.

  The position measuring device 12 is provided as a function of a position information terminal provided in a terminal carried by a pedestrian, for example, a GPS terminal for monitoring the position of an elementary school student or an elderly person, a tablet terminal for Internet communication, a smartphone, and the like. The detailed configuration of the position measuring device 12 will be described later with reference to FIG.

  The GPS satellites 13-1 to 13-4 transmit positioning signals for use in position measurement. Hereinafter, when it is not necessary to distinguish the GPS satellites 13-1 to 13-4 from time to time, they are simply referred to as GPS satellites 13.

  The vehicles 14-1 to 14-7 estimate the position based on the start location, the moving speed, and the moving direction from the position measurement using the GPS satellite 13 and the measurement results by various sensors such as a gyro sensor and an acceleration sensor. The position information can be calculated more accurately than the position measuring device 12 by a technique for performing positioning in combination with calculation processing (Dead Reckoning). The position measurement function in the vehicles 14-1 to 14-7 is provided as a function provided in a GPS device for preventing vehicle theft, a car navigation system that is fixedly mounted on or removed from the vehicle, and the like. Hereinafter, when it is not necessary to distinguish the vehicles 14-1 to 14-7 from each other, they are simply referred to as vehicles 14. In FIG. 1, seven vehicles 14-1 to 14-7 are illustrated. However, one or more vehicles 14 are sufficient, and in order to increase the positioning accuracy of the position measuring device 12, the vehicle 14 is It is desirable that there are two or more.

  The vehicle 14 used in the position measurement system 11 configured as described above communicates between the vehicles 14 for exchanging position information with each other (hereinafter referred to as inter-vehicle communication) for safe driving support. A communication device for performing the above is provided so as to be fixedly mounted or detachable. For example, each vehicle 14 periodically transmits a position information message including type = vehicle, vehicle ID (Identification), vehicle position, positioning time, and vehicle speed in inter-vehicle communication. Similarly, the position measuring device 12 periodically transmits a position information message including type = pedestrian, device ID, device position, and positioning time. At this time, in order to avoid collision of communication packets, the position measurement device 12 and the vehicle 14 each transmit a position information message by randomly shifting the transmission timing by the random backoff function. For this reason, the position information message is transmitted at a timing different from the time of positioning.

  Here, it is assumed that the position measurement device 12 completely receives messages from all the vehicles 14-1 to 14-7 transmitted at random transmission timing within 100 ms. For example, when the speed of the pedestrian is 5 km / h, the distance that can be walked in 100 ms is 0.15 m or less, so that the pedestrian can receive while receiving messages from all the vehicles 14-1 to 14-7. The position of can be regarded as being almost fixed.

  The position measuring device 12 is substantially time synchronized with the vehicle 14 using a GPS module. When the synchronization error between the position measuring device 12 and the vehicle 14 is 1 ms or less, even if the vehicle 14 is traveling at 100 km / h, the influence of the synchronization error on the distance error is 0.03 m or less. Since the positioning time is included in the position information message of the vehicle 14, the position measurement device 12 uses the difference between the reception time and the positioning time of the vehicle 14, the vehicle speed, and the moving direction from the vehicle 14. The vehicle position at the time of receiving the position information message can be calculated.

  As described above, in the position measurement system 11, the position measurement device 12 receives the position information message transmitted and received in the inter-vehicle communication of the vehicles 14-1 to 14-7, and receives the position information message. To estimate the vehicle position of 14-7. Further, the position measuring device 12 uses a communication signal (for example, a wireless local area network (LAN) signal) that transmits a position information message, and distances from the vehicles 14-1 to 14-7 that have received the position information message. Is estimated.

  Therefore, the position measuring device 12 can estimate the position of the pedestrian carrying the position measuring device 12 based on the vehicle positions and distances of the vehicles 14-1 to 14-7. At this time, as the number of vehicles 14 increases, the accuracy of estimating the position of the pedestrian can be improved. Furthermore, the position measuring device 12 can further improve the positioning accuracy of the pedestrian by using the position obtained in this way together with the GPS positioning.

  By the way, the distance estimation by the communication signal can be realized based on the relationship between the signal intensity and the distance when the communication signal is received, but there is a drawback that it is easily influenced by the reflection of the radio wave.

  For example, as shown in FIG. 2, the communication signal transmitted from the vehicle 14 is an indirect wave that directly reaches the position measurement device 12 from the vehicle 14 or is reflected by the buildings 15-1 and 15-2. The wave is received by the position measurement device 12 as a wave. Thus, the communication signal reaches the position measuring device 12 from the vehicle 14 via a plurality of routes.

  Also, FIG. 3 shows channel state information representing the amplitude (signal strength) of communication signals passing through a plurality of paths as shown in FIG. 2 and their arrival times. This channel state information can be directly measured by a dedicated wireless device. Further, a channel response on the frequency axis can be obtained by using an OFDM (Orthogonal Frequency Division Multiplexing) signal from a commercially available wireless LAN card or the like, and channel state information can also be calculated by inverse Fourier transform.

  For example, as shown in FIG. 3A, when there is a direct wave component, the direct wave component arrives earlier than any reflected wave and has no attenuation due to reflection, so that the amplitude is much larger than the subsequent reflected wave. (Signal is strong). On the other hand, as shown in FIG. 3B, when there is no direct wave component, the earliest signal is also a reflected wave, so it is difficult to distinguish it from the subsequent reflected wave by the signal strength. .

  So, if the ratio of “the strength of the signal arriving earliest” and “the strength of the strongest signal among the signals arriving after that” exceeds a certain threshold, it is recognized as a direct wave and is used for distance estimation. Can be used. Or, train the model such as SVM (support vector machine) using each channel state information with and without direct wave component, and whether direct wave is included from channel state information of communication signal Can be identified. As will be described below, in the position measurement device 12, the direct wave component of the communication signal selected from the strength of the direct wave is used to estimate the distance from the vehicle 14, and based on the distance attenuation characteristics of the radio wave, A distance is calculated.

  Next, FIG. 4 is a block diagram illustrating a configuration example of the position measurement device 12.

  As shown in FIG. 4, the position measurement device 12 includes a GPS antenna 21, a communication antenna 22, a satellite signal reception device 23, a communication signal reception device 24, and a positioning processing device 25.

  The GPS antenna 21 converts the positioning signal (electromagnetic wave) transmitted from the GPS satellite 13 into an electric signal and supplies it to the satellite signal receiving device 23. In reality, there are a plurality of GPS satellites 13 around the earth. However, since buildings are adjacent and the sky is not open in the city center, the GPS antenna 21 is transmitted from one GPS satellite 13. In some cases, only a positioning signal (electromagnetic wave) can be received.

  The communication antenna 22 converts a communication signal (electromagnetic wave) used by the vehicle 14 to transmit the position information message into an electric signal and supplies the electric signal to the communication signal receiving device 24.

The satellite signal receiving device 23 receives the positioning signal of the GPS satellite 13 supplied via the GPS antenna 21. Then, the satellite signal receiving device 23 performs position calculation using the orbital calendar of the GPS satellite 13-k obtained by decoding from the positioning signal from the GPS satellite 13-k (k: index of the GPS satellite 13), for example. Thus, the satellite position R _k = (X _Rk , Y _Rk , Z _Rk ) ^T of the GPS satellite 13-k can be calculated. Furthermore, the satellite signal receiving device 23 can measure the pseudo distance with the GPS satellite 13 according to the difference between the transmission time and the reception time of the positioning signal of the GPS satellite 13-k. Therefore, when the positioning signals transmitted from the n GPS satellites 13-1 to 13-n are received, the satellite signal receiving device 23 receives the satellite positions R _{1 to} R _n of the GPS satellites 13-1 to 13- _n. The pseudo distances P _{1 to} P _n are obtained and supplied to the positioning processor 25.

  The communication signal receiving device 24 acquires a position information message of the vehicle 14 by decoding a communication signal supplied via the communication antenna 22 and supplies the position information message to the positioning processing device 25. Further, the communication signal receiving device 24 measures the strength (channel state information) for each arrival time of the communication signal as shown in FIG. 3 and supplies the strength of the communication signal to the positioning processing device 25. To do.

The positioning processor 25 receives the satellite positions R _{1 to} R _n and pseudoranges P _{1 to} P _n supplied from the satellite signal receiver 23, and the position information message and communication signal strength supplied from the communication signal receiver 24. Based on this, a positioning process for measuring the position of the position measuring device 12 is performed. The positioning processing device 25 includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), flash memory (for example, EEPROM (Electronically Erasable and Programmable Read Only Memory)), and the like. A functional block that executes a positioning process is configured by loading a program stored in a ROM or flash memory into a RAM and executing the program.

  That is, as illustrated, the positioning processing device 25 includes a signal identification selection unit 31, an estimation unit 32, and a positioning unit 33 as functional blocks.

  As described above with reference to FIGS. 2 and 3, the signal identification selection unit 31 determines the distance from the vehicle 14 based on the strength (channel state information) of the communication signal supplied from the communication signal receiving device 24. Identify communication signals that contain direct waves that can be used to determine. Then, the signal identification selection unit 31 selects a communication signal including a direct wave from the communication signals received by the communication signal receiving device 24, and supplies the position information message transmitted by the communication signal to the estimation unit 32. To do. Further, the signal identification selection unit 31 supplies the estimation unit 32 with the intensity of the direct wave included in the selected communication signal.

  Based on the position information message supplied from the signal identification selection unit 31, the estimation unit 32 estimates the vehicle position of the vehicle 14 that has transmitted the position information message. For example, the estimation unit 32 performs transmission / reception by calculating the following equation (1) based on the vehicle position, vehicle speed, and positioning time included in the position information message, and the reception time when the position information message is received. Estimate the vehicle position at the time.

For example, the estimation unit 32 estimates the vehicle position M _i = (X _Mi , Y _Mi , Z _Mi ) ^T at the time of transmission / reception based on the position information message from the vehicle 14-i (i: index of the vehicle 14). . Furthermore, the estimation unit 32 can estimate the distance D _i to the vehicle 14-i based on the strength of the direct wave included in the communication signal supplied from the signal identification selection unit 31. Therefore, when receiving the position information message transmitted from the m of vehicles 14-1 to 14-m, the estimation unit 32, the vehicle 14-1 to 14-m each vehicle position M ₁ to M _m and the distance D _{1 to} D _m are estimated and supplied to the positioning unit 33.

The positioning unit 33 estimates the satellite positions R _{1 to} R _n and pseudoranges P _{1 to} P _{n of} the GPS satellites 13-1 to 13 -n calculated by the satellite signal receiver 23, and the estimation unit 32. Based on the vehicle positions M _{1 to} M _m and the distances D _{1 to} D _m of the vehicles 14-1 to 14-m, the position of the position measuring device 12 is calculated.

For example, the satellite positions R _{1 to} R _n and the pseudo distances P _{1 to} P _n are expressed by the following equation (2) using the position error of the position measurement device 12 and the distance error δ corresponding to the time error of the position measurement device 12. It is represented by

Similarly, the vehicle positions M _{1 to} M _m and the distances D _{1 to} D _m are expressed by the following equation (3) using the position r of the position measuring device 12.

  Therefore, the positioning unit 33 can determine the position of the position measuring device 12 by obtaining the position r that most satisfies the expressions (2) and (3). For example, if the total number of GPS satellites 13 and vehicles 14 is 4 or more, the positioning unit 33 can obtain the position r, and the positioning accuracy can be improved as the total number increases.

  Furthermore, for example, the positioning unit 33 estimates the measurement error when measuring the pseudo distance P of the GPS satellite 13 and the distance estimation when estimating the distance D of the vehicle 14 with respect to the expressions (2) and (3). By estimating the error and performing weighting according to the dispersion values of the measurement error and the distance estimation error, the position of the position measuring device 12 can be calculated more accurately.

  Next, processing executed in the position measurement system 11 will be described with reference to FIGS.

  FIG. 5 is a flowchart for explaining processing performed in the vehicle 14.

  For example, when the safe driving support system included in the vehicle 14 is activated, the process is started. In step S11, the vehicle 14 determines whether or not it is a transmission timing for transmitting the position information message, and determines that the transmission timing is reached. Wait until processing. The vehicle 14 is set with a certain period for periodically transmitting the position information message. When the certain period has elapsed since the start of processing, or when the certain period has elapsed from the previous transmission timing, The vehicle 14 determines that the transmission timing has come. And when it determines with the vehicle 14 having become transmission timing, a process progresses to step S12.

  In step S12, the vehicle 14 transmits a position information message including information such as type = vehicle, vehicle ID, vehicle position, positioning time, and vehicle speed. And after the process of step S12, a process returns to step S11 and a positional information message is periodically transmitted from the vehicle 14 by repeating the same process hereafter.

  FIG. 6 is a flowchart for explaining processing performed in the position measurement apparatus 12.

For example, the processing is started when control by a higher-level control device (not shown) is performed so as to start processing for measuring the position of the position measuring device 12. In step S <b> 21, the satellite signal receiving device 23 receives the positioning signals transmitted from the GPS satellites 13-1 to 13-n via the GPS antenna 21. Then, as described above, the satellite signal receiving device 23 obtains the satellite positions R _{1 to} R _n and the pseudo distances P _{1 to} P _n of the GPS satellites 13-1 to 13-n, and performs the positioning of the positioning processing device 25. To the unit 33.

  In step S <b> 22, the communication signal receiving device 24 determines whether a position information message has been transmitted from the vehicle 14. For example, when the position information message is transmitted (step S12 in FIG. 5) when the position information message is transmitted in the nearby vehicle 14 that is within a distance capable of communicating with the position measurement device 12, the communication is performed. The signal receiving device 24 determines that a position information message has been transmitted from the vehicle 14.

  In step S22, when the communication signal receiving device 24 determines that the position information message has been transmitted from the vehicle 14, the process proceeds to step S23.

In step S <b> 23, the communication signal receiving device 24 receives the position information message transmitted from the vehicle 14 via the communication antenna 22 and supplies it to the signal identification selection unit 31 of the positioning processing device 25. Thereby, the signal identification selection unit 31 selects the communication signal including the direct wave from the communication signals received by the communication signal receiving device 24, and the position information message transmitted by the communication signal and the communication signal The direct wave intensity is supplied to the estimation unit 32. Then, as described above, the estimation unit 32 estimates the vehicle positions M _{1 to} M _m and the distances D _{1 to} D _m of the vehicles 14-1 to 14-m, and supplies them to the positioning unit 33.

In step S24, the positioning unit 33 is estimated from the satellite positions R _{1 to} R _n and the pseudoranges P _{1 to} P _n obtained from the positioning signal received in step S21, and the position information message received in step S23. Based on the vehicle positions M _{1 to} M _m and the distances D _{1 to} D _m , the position r of the position measuring device 12 is calculated using the above-described equations (2) and (3).

On the other hand, when the communication signal receiving device 24 determines in step S22 that the position information message has not been transmitted from the vehicle 14, the process proceeds to step S25. In other words, in this case, the vehicle 14 that transmits the position information message does not exist in the vicinity of the position measurement device 12, and in step S25, the positioning unit 33 determines the satellite position R ₁ to the satellite position R ₁ through the positioning signal received in step S21. The position r of the position measuring device 12 is calculated only by R _n and the pseudo distances P _{1 to} P _n .

  And after the process of step S24 or S25, a process returns to step S21 and the same process is repeated hereafter.

  As described above, the position measurement system 11 uses the position information messages from the plurality of vehicles 14 in addition to the positioning signals from the plurality of GPS satellites 13 to measure the position of the position measurement device 12. The accuracy can be further improved.

  Next, a configuration example of the second embodiment of the position measurement system to which the present technology is applied will be described with reference to FIGS.

  As shown in FIG. 7, in the position measurement system 11 </ b> A, the vehicle 14 can communicate with the server device 42 via the network 41, and the position information of the plurality of access points 51 arranged on the road side is the vehicle 14. Is stored in the server device 42.

  As shown in FIG. 8, in the position measurement system 11 </ b> A, the position measurement device 12 can obtain the position information of a plurality of access points 51 even if there are a few nearby vehicles 14 that are within a communicable distance. By using it, the position can be measured with higher accuracy.

  7 and 8, the position of the position measuring device 12 is measured using the position information of the five access points 51-1 to 51-5. Hereinafter, the access point 51- When it is not necessary to distinguish each of 1 to 51-5, they are simply referred to as an access point 51. In addition to preparing a dedicated device as the server device 42, for example, any one access point 51 may be used as the server device 42.

  For example, in an urban area, an access point 51 that is a wireless device that performs communication using a wireless LAN is increasingly installed on the roadside as a kind of roadside device. However, since the access point 51 is not measured for position information, it is costly to manually measure the installed position.

  Therefore, in the position measurement system 11A, the vehicle 14 receives the communication signal used by the access point 51 to transmit the beacon message, performs signal identification selection, and when there is a direct wave, receives the direct wave of the communication signal. The distance to the access point 51 is estimated based on the intensity. Then, the vehicle 14 transmits an access point measurement message including the access point ID for recognizing the access point 51 read from the beacon message, the estimated distance of the access point 51, and the vehicle position of the vehicle 14 to the server device 42. . Note that the vehicle 14 does not transmit an access point measurement message when there is no direct wave.

  In response to this, the server device 42 estimates the position of the access point 51 based on the vehicle position of the vehicle 14 and the estimated distance of the access point 51, and associates it with the access point ID of the access point 51. Register the information in the database.

  Thereafter, the position measuring device 12 receives a beacon message transmitted from the access point 51, transmits the access point ID of the access point 51 included in the beacon message to the server device 42, and requests position information. Then, in response to the request, the server device 42 reads the position information of the access point 51 corresponding to the access point ID transmitted from the position measuring device 12 from the database, and transmits it to the position measuring device 12.

  As a result, the position measurement device 12 uses the position and distance of the access point 51 in addition to the positioning signals from the plurality of GPS satellites 13 and the position information messages from the plurality of vehicles 14, thereby more accurately. The position can be calculated. If the position information of the access point 51 is already registered in the database of the server device 42, the position measuring device 12 calculates the position using the position information of the access point 51 even if the vehicle 14 is not in the vicinity. can do.

  Next, processing executed in the position measurement system 11A will be described with reference to FIGS.

  FIG. 9 is a flowchart for explaining processing performed in the access point 51.

  For example, when the access point 51 is activated, the process is started. In step S31, the access point 51 determines whether or not it is a transmission timing for transmitting a beacon message, and waits for a process until it is determined that a beacon message is reached. To do. In the access point 51, a fixed period for periodically transmitting the beacon message is set, and when the fixed period has elapsed since the start of processing, or when the fixed period has elapsed from the previous transmission timing, The access point 51 determines that the transmission timing has come. If the access point 51 determines that the transmission timing has come, the process proceeds to step S32.

  In step S <b> 32, the access point 51 transmits a beacon message including the access point ID of the access point 51. And after the process of step S32, a process returns to step S31 and a beacon message is periodically transmitted from the access point 51 by repeating the same process hereafter.

  FIG. 10 is a flowchart for explaining processing performed in the vehicle 14.

  For example, the process is started when the safe driving support system included in the vehicle 14 is activated. In step S <b> 41, the vehicle 14 determines whether or not a beacon message has been transmitted from the access point 51. For example, when a beacon message is transmitted at a nearby access point 51 at a distance where communication with the vehicle 14 can be performed, and the beacon message is transmitted (step S32 in FIG. 9), the vehicle 14 It is determined that a beacon message has been transmitted from the access point 51.

  If the vehicle 14 determines in step S41 that a beacon message has been transmitted from the access point 51, the process proceeds to step S42.

  In step S <b> 42, the vehicle 14 receives a beacon message transmitted from the access point 51. And the vehicle 14 estimates the distance with the access point 51 which transmitted the beacon message based on the intensity | strength of the direct wave of the transmission signal utilized for transmission of a beacon message.

  In step S <b> 43, the vehicle 14 transmits the access point measurement message including the access point ID of the access point 51 read from the beacon message, the estimated distance of the access point 51, and the vehicle position of the vehicle 14 via the network 41. 42.

  After the process of step S43, or when it is determined in step S41 that the beacon message has not been transmitted from the access point 51, the process proceeds to step S44.

  In steps S44 and S45, the vehicle 14 performs the process of periodically transmitting the position information message in the same manner as in steps S11 and S12 of FIG. 5, and then the process returns to step S41. Thereafter, the same process is repeated. It is.

  FIG. 11 is a flowchart for explaining processing performed in the server device 42.

  In step S <b> 51, the server device 42 determines whether an access point measurement message has been transmitted from the vehicle 14. For example, when the vehicle 14 transmits an access point measurement message in step S43 in FIG. 10, the server device 42 determines that the access point measurement message has been transmitted from the vehicle 14, and the process proceeds to step S52.

  In step S <b> 52, the server device 42 receives the access point measurement message transmitted from the vehicle 14, and stores the access point ID of the access point 51, the estimated distance of the access point 51, and the vehicle position of the vehicle 14.

In step S <b> 53, the server device 42 estimates the position of the access point 51 for each access point 51 based on the access point measurement message received from the plurality of vehicles 14 because the access point 51 is fixed. . For example, the position of the access point 51 is calculated using the above-described equation (3), using the vehicle position M _{i of} the vehicle 14-i and the distance D _i between the access point 51 and the vehicle 14-i. The position r of 51 can be estimated. Then, the server device 42 associates the estimated position r with the access point ID of the access point 51 and stores it in the database as access point position information.

  And after the process of step S53, or when it determines with the access point measurement message not having been transmitted from the vehicle 14 in step S51, a process progresses to step S54.

  In step S54, the server device 42 determines whether or not the access point ID has been transmitted from the position measurement device 12. For example, when the position measurement device 12 transmits an access point ID in step S66 of FIG. 12 to be described later, the server device 42 determines that the access point ID is transmitted from the position measurement device 12, and the process proceeds to step S55. move on.

  In step S55, the server apparatus 42 receives the access point ID transmitted from the position measuring apparatus 12, and searches the database for access point position information associated with the access point ID. Then, the server device 42 transmits the access point position information obtained as a search result to the position measurement device 12.

  After the process of step S55, or when it is determined in step S54 that the access point ID has not been transmitted from the position measurement device 12, the process returns to step S51, and the same process is repeated thereafter.

  12 and 13 are flowcharts for explaining processing performed in the position measurement device 12. FIG.

  For example, the processing is started when control by a higher-level control device (not shown) is performed so as to start processing for measuring the position of the position measuring device 12. In steps S61 to S63, the position measurement device 12 performs the same processing as steps S21 to S23 in FIG.

  After the process of step S63, the process proceeds to step S64, and the communication signal receiving device 24 determines whether or not a beacon message has been transmitted from the access point 51. For example, when a beacon message is transmitted at a nearby access point 51 located at a distance where communication with the position measurement device 12 can be performed, and the beacon message is transmitted (step S32 in FIG. 9), the position measurement is performed. The device 12 determines that a beacon message has been transmitted from the access point 51.

  If the position measurement device 12 determines in step S64 that a beacon message has been transmitted from the access point 51, the process proceeds to step S65.

  In step S <b> 65, the position measurement device 12 receives a beacon message transmitted from the access point 51. Then, the position measurement device 12 estimates the distance from the access point 51 that transmitted the beacon message based on the strength of the direct wave of the transmission signal used for transmitting the beacon message. At this time, as described above, the position measurement device 12 selects a communication signal including a direct wave component and uses it for estimating the distance from the access point 51.

  In step S <b> 66, the position measurement device 12 transmits the access point ID of the access point 51 included in the beacon message received in step S <b> 64 to the server device 42 via the network 41.

  In response to the transmission of the access point ID, when the server apparatus 42 transmits the access point position information in step S55 of FIG. 11, the position measurement apparatus 12 receives the access point position information in step S67.

  In step S68, the position measurement device 12 determines the satellite position R and the pseudo distance P obtained from the positioning signal received in step S61, the vehicle position M and the distance D estimated from the position information message received in step S63, and Based on the distance from the access point 51 estimated in step S65 and the position information of the access point received in step S67, the position r of the position measurement device 12 is calculated using the above-described equations (2) and (3). To do.

  On the other hand, when it determines with the beacon message not having been transmitted from the access point 51 in step S64, a process progresses to step S69. In step S69, the position measurement device 12 uses the positioning signal received in step S61 and the vehicle position M and the distance D estimated from the position information message received in step S63. The position r of the position measuring device 12 is calculated using (3).

  On the other hand, if it is determined in step S62 that the position information message has not been transmitted from the vehicle 14, the process proceeds to step S71 in FIG.

  In step S71, the communication signal receiving device 24 determines whether or not a beacon message has been transmitted from the access point 51, as in step S64 of FIG. If the position measurement device 12 determines in step S71 that a beacon message has been transmitted from the access point 51, the process proceeds to step S72.

  Then, in steps S72 to S74, the same processing as in steps S65 to S67 in FIG. 12 is performed, and in step S75, the position measurement device 12 estimates the positioning signal received in step S61 and in step S72. Based on the distance to the access point 51 and the position information of the access point received in step S74, the position r of the position measuring device 12 is calculated using the above-described equations (2) and (3).

  On the other hand, if it is determined in step S71 that a beacon message has not been transmitted from the access point 51, the process proceeds to step S76. In this case, in step S76, the position measurement device 12 calculates the position r of the position measurement device 12 using only the satellite position R and the pseudorange P obtained from the positioning signal received in step S61.

  Then, after the process of step S68, S69, S75, or S76, the process returns to step S61, and the same process is repeated thereafter.

  As described above, in the position measurement system 11A, the position of the position measurement device 12 can be calculated using the position and distance of the access point 51, so that the position measurement system 11A of FIG. In addition, the position of the position measuring device 12 can be measured.

  In the position measurement system 11A, instead of calculating its own position by the position measurement device 12, the server device 42 calculates the position of the position measurement device 12 (the reception position of the positioning signal and the position information message). Can do.

  A modification of the processing performed in the position measurement system 11A will be described with reference to FIGS.

  14 and 15 are flowcharts for explaining a modification of the processing performed in the position measurement device 12.

  In steps S81 to S85, the position measurement device 12 performs the same processing as steps S61 to S65 in FIG.

  In step S <b> 86, the position measurement device 12 transmits positioning information necessary for measuring its own position to the server device 42 via the network 41. Here, the positioning information transmitted by the position measuring device 12 includes the satellite position R and the pseudo distance P corresponding to the number of GPS satellites 13 obtained from the positioning signal received in step S81, and the position information message received in step S83. Is estimated from the vehicle position M and distance D according to the number of vehicles 14 estimated from the above, the access point ID included in the beacon message according to the number of access points 51 received at step S85, and the beacon message. The distance to the access point 51 is included.

  In step S87, the position measuring device 12 performs positioning calculation in the server device 42 based on the positioning information transmitted in step S86, and the position information of the position measuring device 12 is transmitted (step S106 in FIG. 16 described later). And the position information is received.

  If it is determined in step S84 that a beacon message has not been transmitted from the access point 51, the process proceeds to step S88, and the position measurement device 12 transmits positioning information to the server device. In this case, the positioning information transmitted by the position measuring device 12 includes the satellite position R and the pseudorange P corresponding to the number of GPS satellites 13 obtained from the positioning signal received in step S81, and the position received in step S83. A vehicle position M and a distance D corresponding to the number of vehicles 14 estimated from the information message are included.

  In step S89, the position measuring device 12 performs positioning calculation in the server device 42 based on the positioning information transmitted in step S88, and the position information of the position measuring device 12 is transmitted (step S106 in FIG. 16 described later). And the position information is received.

  On the other hand, if it is determined in step S82 that the position information message has not been transmitted from the vehicle 14, the process proceeds to step S91 in FIG.

  In step S91, the communication signal receiving device 24 determines whether or not a beacon message has been transmitted from the access point 51, as in step S84 of FIG. If the position measuring device 12 determines in step S91 that a beacon message has been transmitted from the access point 51, the process proceeds to step S92.

  In step S92, the position measurement device 12 receives the beacon message transmitted from the access point 51, estimates the distance from the access point 51 that transmitted the beacon message, and transmits the positioning information in step S93. To do. In this case, the positioning information transmitted in step S93 includes the satellite position R and the pseudorange P corresponding to the number of GPS satellites 13 obtained from the positioning signal received in step S81, and the access point 51 received in step S92. The access point ID included in the beacon message corresponding to the number and the distance to the access point 51 estimated from the beacon message are included.

  In step S94, the position measurement device 12 receives the position information as in step S87 of FIG.

  On the other hand, if it is determined in step S91 that a beacon message has not been transmitted from the access point 51, the process proceeds to step S95. In this case, in step S95, the position measuring device 12 calculates the position r of the position measuring device 12 using only the satellite position R and the pseudorange P obtained from the positioning signal received in step S81.

  And after the process of step S87, S89, S94, or S95, a process returns to step S81 and the same process is repeated hereafter.

  FIG. 16 is a flowchart for explaining a modification of the processing performed in the server device 42.

  In steps S101 to S103, the server apparatus 42 performs the same processing as steps S51 to S53 in FIG.

  In step S <b> 104, the server device 42 determines whether or not the positioning information has been transmitted from the position measurement device 12. As described above, when the position measurement device 12 transmits the positioning information in step S86 or S88 in FIG. 14 or step S93 in FIG. 15, the server device 42 determines that the positioning information has been transmitted from the position measurement device 12. Then, the process proceeds to step S105.

  In step S105, the server device 42 receives the positioning information transmitted from the position measuring device 12, searches the database for the position of the access point ID based on the positioning information, and further determines the position of the position measuring device 12. Perform the positioning calculation to be calculated. That is, the processing performed by the position measurement device 12 in step S68 or S69 in FIG. 12 or step S75 in FIG. 13 is performed in the server device 42, and the position of the position measurement device 12 is calculated.

  In step S <b> 106, the server device 42 transmits the position information of the position measuring device 12 obtained by the positioning calculation in step S <b> 105 to the position measuring device 12. Note that the position information of the position measurement device 12 transmitted by the server device 42 is received by the position measurement device 12 in step S87 or S89 in FIG. 14 or step S94 in FIG.

  After the process of step S106 or when it is determined in step S104 that the positioning information has not been transmitted from the position measuring device 12, the process returns to step S101, and the same process is repeated thereafter.

  As described above, in the position measurement system 11A, for example, by calculating the position of the position measurement device 12 in the server device 42 having a higher processing capability than the position measurement device 12, the entire system performs processing at a higher speed. Can do. In addition, it is not essential to receive the positioning signal in step S81. For example, the position measurement device 12 does not receive the positioning signal and receives position information (position information message other than the positioning signal and beacon message from the server device 41 in step S87). It is also possible to receive the required position information). In this case, for example, in the position measuring device 12, it is not necessary to provide the positioning unit 33 of FIG. 4, and the configuration of the position measuring device 12 can be simplified. Further, even with the position measuring device 12 having a low processing capability, the position can be obtained with higher accuracy.

  In the position measurement systems 11 and 11A, when calculating the position of the position measurement device 12, the position calculation may be performed by appropriately selecting an appropriate coordinate system. For example, by selecting a local coordinate system based on the vicinity of the position measuring device 12 instead of a global coordinate system based on GPS, the positioning calculation can be simplified, and errors in the positioning calculation can be generated. Can be suppressed.

  In addition, as described above, in the position measurement device 12, the estimation unit 32 performs the transmission / reception based on the vehicle position, the vehicle speed, and the positioning time included in the position information message and the reception time when the position information message is received. The vehicle position is estimated and used to calculate the position of the position measuring device 12. In addition, for example, the vehicle position included in the position information message may be used as it is for the calculation of the position of the position measurement device 12.

  As described above, in the position measurement systems 11 and 11A, the positioning accuracy of the position measurement device 12 can be improved. Therefore, by transmitting accurate position information to the vehicle 14 via inter-step communication, for example, the prospect Even if the location does not work, the distance between the pedestrian carrying the position measuring device 12 and the vehicle 14 can be accurately calculated. Thereby, in the vehicle 14, the alerting according to the distance with a pedestrian can be performed, and a pedestrian can be protected from a traffic accident. At this time, since the position of the position measurement device 12 can be calculated with high accuracy, it is possible to avoid erroneous alerting and improve the reliability of alerting.

  In the position measurement systems 11 and 11A, the context of the pedestrian is obtained based on accurate position information of the pedestrian carrying the position measurement device 12. Thereby, the transmission frequency etc. which transmit position information by communication between steps can be controlled, for example, the position information from a pedestrian with high danger can be transmitted to the vehicle 14 with high priority.

  Furthermore, the position measurement systems 11 and 11A can be applied to various position information services. For example, when passing through a store that is often visited by pedestrians in a shopping street, coupons, discount information, and the like are appropriately provided with higher accuracy. Can be sent.

  Note that the processes described with reference to the flowcharts described above do not necessarily have to be processed in chronological order in the order described in the flowcharts, but are performed in parallel or individually (for example, parallel processes or objects). Processing). The program may be processed by one CPU, or may be distributedly processed by a plurality of CPUs.

  Further, the above-described series of processing can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software executes various functions by installing a computer incorporated in dedicated hardware or various programs. For example, the program is installed in a general-purpose personal computer from a program recording medium on which the program is recorded. Moreover, the figure of this application is a conceptual diagram, for example, the signal identification selection part 31, the estimation part 32, the positioning part 33, etc. of the position measuring device 12 shown in FIG. 4 can also be comprised with software, and the GPS antenna 21 The communication antenna 22 can also be used as a single antenna.

  FIG. 17 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processing by a program.

  In the computer, the CPU 101, ROM 102, and RAM 103 are connected to each other by a bus 104.

  An input / output interface 105 is further connected to the bus 104. The input / output interface 105 includes an input unit 106 including a touch panel, buttons, a microphone, an output unit 107 including a display and a speaker, a storage unit 108 including a hard disk and a non-volatile memory, and a communication unit 109 including a network interface. A drive 110 for driving a removable medium 111 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory is connected.

  In the computer configured as described above, the CPU 101 loads, for example, the program stored in the storage unit 108 to the RAM 103 via the input / output interface 105 and the bus 104 and executes the program. Is performed.

  The program executed by the computer (CPU 101) is, for example, a magnetic disk (including a flexible disk), an optical disk (CD-ROM (Compact Disc-Read Only Memory), DVD (Digital Versatile Disc), etc.), a magneto-optical disk, or a semiconductor. The program is recorded on a removable medium 111 that is a package medium including a memory or the like, or is provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

  The program can be installed in the storage unit 108 via the input / output interface 105 by attaching the removable medium 111 to the drive 110. Further, the program can be received by the communication unit 109 via a wired or wireless transmission medium and installed in the storage unit 108. In addition, the program can be installed in the ROM 102 or the storage unit 108 in advance.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

  Note that the present embodiment is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present disclosure.

  11 and 11A position measurement system, 12 position measurement device, 13 GPS satellite, 14 vehicle, 21 GPS antenna, 22 communication antenna, 23 satellite signal reception device, 24 communication signal reception device, 25 positioning processing device, 31 signal identification selection unit, 32 estimation units, 33 positioning units, 41 networks, 42 server devices, 51 access points

Claims (10)

A satellite signal receiving unit that receives a positioning signal transmitted from a satellite for use in position measurement and measures the position and distance of the satellite that has transmitted the positioning signal;
A communication signal receiving unit for receiving a communication signal used for transmitting a position information message including at least the position of the vehicle;
An estimation unit that estimates a distance from the vehicle that has transmitted the position information message according to the signal strength when the communication signal is received;
Based on the position and distance of the satellite measured by the satellite signal receiving unit, the position of the vehicle included in the position information message, and the distance from the vehicle estimated by the estimation unit, the position measuring device itself And a positioning unit that measures the position of the position measuring device. The communication signal receiving unit receives a communication signal that is transmitted from a wireless device that performs wireless communication and is used for transmitting a beacon message including at least identification information for identifying the wireless device itself, and is connected via a network. Obtaining the position of the wireless device identified by the identification information from the database of the server device,
The estimation unit estimates a distance from the wireless device that transmitted the beacon message according to the signal strength when the communication signal is received,
The positioning unit further measures the position of the position measuring device itself by further using the position of the wireless device acquired by the communication signal receiving unit and the distance from the wireless device estimated by the estimating unit. The position measuring device according to claim 1. Further comprising: a signal identification selection unit that identifies whether or not the communication signal received by the communication signal receiving unit includes a direct wave component, and that selects the communication signal that includes the direct wave component;
The position measurement apparatus according to claim 1, wherein the estimation unit uses only the communication signal selected by the signal identification selection unit for the estimation of the distance. The position information message further includes a speed of the vehicle that has transmitted the position information message, a positioning time at which the position of the vehicle is determined,
The estimation unit estimates the position of the vehicle at the time of receiving the position information message based on the position, speed, and positioning time of the vehicle and the reception time of receiving the position information message,
The positioning unit uses the position of the vehicle estimated by the estimation unit instead of the position of the vehicle included in the position information message for measurement of the position of the position measuring device itself. 4. The position measuring device according to any one of 3 above. The positioning unit estimates a measurement error when measuring the distance of the satellite and a distance estimation error when estimating the distance of the vehicle, and performs weighting according to a variance value of the measurement error and the distance estimation error. The position measuring device according to claim 1, wherein the position measuring device measures the position of the position measuring device. Receiving a positioning signal transmitted from a satellite for use in position measurement, and measuring the position and distance of the satellite that transmitted the positioning signal;
Receiving a communication signal used to transmit a position information message including at least the position of the vehicle;
According to the signal strength when the communication signal is received, the distance to the vehicle that transmitted the location information message is estimated,
A position measuring method for a position measuring device, comprising: measuring the position of the position measuring device itself based on the position and distance of the satellite, the position of the vehicle included in the position information message, and the distance from the vehicle. Receiving a positioning signal transmitted from a satellite for use in position measurement, and measuring the position and distance of the satellite that transmitted the positioning signal;
Receiving a communication signal used to transmit a position information message including at least the position of the vehicle;
According to the signal strength when the communication signal is received, the distance to the vehicle that transmitted the location information message is estimated,
Based on the position and distance of the satellite, the position of the vehicle included in the position information message, and the distance to the vehicle, a process including the step of measuring the position of the position measuring device itself is performed on the computer of the position measuring device. The program to be executed. In a position measuring system including a satellite, a vehicle, and a position measuring device,
The satellite transmits a positioning signal for use in position measurement,
The vehicle transmits a position information message including at least the position of the vehicle;
The position measuring device includes:
Receiving a positioning signal transmitted from the satellite for use in position measurement, and measuring the position and distance of the satellite that transmitted the positioning signal;
Receiving a communication signal used to transmit a position information message including at least the position of the vehicle;
According to the signal strength when the communication signal is received, the distance to the vehicle that transmitted the location information message is estimated,
A position measurement system that measures the position of the position measurement device itself based on the position and distance of the satellite, the position of the vehicle included in the position information message, and the distance from the vehicle. The position measurement system further includes a wireless device and a server device,
The radio transmits a beacon message including at least identification information for identifying the radio itself;
In response to a request from the position measuring device, the server device transmits the position of the wireless device registered in the database in advance.
The position measuring device includes:
Received from the database of the server device connected via a network is a communication signal used for transmission of a beacon message transmitted from the wireless device and including at least identification information for identifying the wireless device itself. Obtaining the position of the radio identified by
According to the signal strength at the time of receiving the communication signal, estimate the distance from the wireless device that transmitted the beacon message,
The position measurement system according to claim 8, wherein the position of the position measurement device itself is measured by further using the position of the wireless device and the distance from the wireless device. The vehicle receives a communication signal used for transmission of the beacon message transmitted from the wireless device, and the wireless device that has transmitted the beacon message according to the signal strength when the communication signal is received. Estimating the distance, and transmitting a measurement message including the identification information of the wireless device, the distance to the wireless device, and the position of the vehicle itself to the server device connected via a network,
The server device estimates the position of the wireless device based on the measurement message transmitted from the vehicle, and registers it in the database in association with identification information of the wireless device. The described position measuring system.

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