JP2005352610A - Warning system and moving body terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a warning system that can surely detect a road where a moving body is traveling and precisely give a warning of a collision against a transmission-side moving body even when the precision of position coordinates of the current position of the transmission-side moving body is inferior, and a moving body terminal. <P>SOLUTION: Disclosed is the warning system that gives a warning of a collision of moving bodies by making a plurality of moving bodies send and receive position information on current positions, and is characterized in that a transmission-side moving body stores a plurality of detected position coordinates and transmits the plurality of stored position coordinates. A reception-side moving body receives the plurality of position coordinates sent from the transmission-side moving body, performs map matching of the current position of the transmission-side moving body on a map based upon the plurality of position coordinates and map information, and gives a warning of a collision based upon the map-matched current position of the transmission-side moving body and the current position of the local moving body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an alarm system for a moving body that warns of a collision between moving bodies, in particular, in a moving body such as a vehicle, by transmitting / receiving position information of a current position between a plurality of moving bodies using short-range radio, The present invention relates to an alarm system for a mobile unit that warns of a collision between mobile units and a mobile unit terminal.

  As collisions between moving bodies, in particular, collisions between vehicles, most of them are collisions at the intersection. Therefore, knowing from what direction and at what timing other vehicles are entering the intersection is a powerful solution for preventing a collision accident at the encounter.

  One way for the driver to know from which direction and at what timing other vehicles are entering the intersection is to obtain the driving information of the vehicles near the intersection from AHS (Advanced Cruise-Asist Highway Systems). There is a way to do it. However, it is expensive and expensive to install AHS at intersections with a small amount of traffic or at intersections on narrow roads. However, there are many cases where there is no signal at intersections where traffic is small or intersections on narrow roads, and the risk of a collision accident at the encounter is high.

Therefore, recently, a system for exchanging information through inter-vehicle communication using short-range wireless and confirming the position, traveling direction, and speed of another vehicle has been developed. For example, in Patent Document 1, operation information of operation switches, position information, speed information, yaw rate, lateral acceleration, and other vehicle travel state information, and image information captured by other vehicles are communicated from other vehicles. And a technique for displaying information such as the traveling state and relative position of other vehicles existing in the vicinity of the host vehicle, image information, road conditions, signs, and the like on an alarm / display unit is disclosed. In Patent Document 1, position information from another vehicle is information for determining a traveling road of the other vehicle.
JP-A-11-195196

  However, if the accuracy of the position information from other vehicles is poor, the map information of the host vehicle does not always match the traveling road. For example, as shown in FIG. 7, when the host vehicle 70 is used, and the other vehicle is actually on 71 on the road 74, if the current position received from the other vehicle is 71 a, the map of the host vehicle There is a possibility of mapping 73 on the road 75. In such a case, although the intersection where the other vehicle passes is actually X, it is determined that the vehicle passes through the intersection Y, and the intersection where the host vehicle and the other vehicle meet is also erroneously recognized from X to Y. End up.

  In the example of FIG. 7, if the intersection that is met is erroneously recognized as Y, the vehicle 70 will pass first and there is no possibility of a collision with another vehicle, so no warning is given. However, in reality, there is a high possibility of meeting at the intersection X, and there is no alarm even if there is a possibility of a collision at the encounter, so the danger increases. On the other hand, if the intersection where the other vehicle passes is actually Y but it is erroneously recognized that the vehicle passes through the intersection X, an unnecessary warning is issued.

  In this way, even if the accuracy of the position coordinates of the current position deteriorates, the current position is always detected on the transmission side and map matching is always possible on the map, so it is possible to accurately determine the road that is actually running by map matching The nature is high. Therefore, it is conceivable to transmit the position information of the current position that has been map-matched from the transmitting side, but if the maps held by both moving bodies are different, the position of the transmitting side moving body is accurately determined at the receiving side. It may not be possible to grasp. It is also conceivable to perform a map matching on the receiving side and detect the intersection where the transmitting side moving body guesses the road on which it is traveling, but only when both moving bodies are close to each other within a predetermined distance. Since the number of received position coordinates is small for map matching only with the position coordinates received in real time, the road on which the moving body on the transmitting side is actually traveling cannot be accurately determined on the receiving side.

  In view of the above-mentioned conventional problems, the present invention can reliably detect a moving road even when the accuracy of the position coordinates of the current position of the mobile body on the transmission side is poor. Provided are an alarm system and a mobile terminal for accurately executing a collision alarm with a mobile object.

  In order to solve this problem, the alarm system of the present invention includes a first mobile terminal included in a first mobile body and a second mobile terminal included in a second mobile body, wherein the first mobile terminal includes the first mobile terminal. A collision between the first mobile unit and the second mobile unit is warned based on positional information of the mobile unit that is directly transmitted and received when the separation distance is equal to or smaller than a predetermined distance between the mobile unit and the second mobile unit. In the alarm system, the first mobile terminal detects a position coordinate of a current position of the first mobile body based on a detection result of the first detection means, Transmitting means for transmitting a plurality of position coordinates indicating the movement progress of the first mobile body, wherein the second mobile terminal stores storage means for storing map information, and the current status of the second mobile body Second detection means for detecting position coordinates of the position, and detected by the second detection means First determination means for determining a current position on the road of the map information of the second moving body based on the position coordinates and the map information; and the plurality of position coordinates transmitted from the transmission means. Receiving means for receiving, and second determining means for determining a current position on the road of the map information of the first moving body based on the plurality of position coordinates and the map information received by the receiving means. And determining the possibility of collision based on the current position of the first moving body, the current position of the second moving body, and the map information determined by the first and second determining means. The apparatus includes a determination unit and an alarm unit that issues a collision alarm when the determination unit determines that there is a possibility of a collision.

  Here, the first mobile terminal further includes at least one of a branch point, a curve, or a merging point of the road on which the first mobile body has moved from the position coordinates detected by the first detection unit. Selecting means for selecting position coordinates detected in the vicinity of the point, and the transmitting means transmits the position coordinates selected by the selecting means. Further, the first mobile terminal further includes a storage unit that stores map information, a position coordinate detected by the first detection unit, and the map information, and the map information. Determining means for determining the density of roads around the current position; and setting means for setting the number of the plurality of position coordinates to be transmitted by the transmitting means based on the density determined by the determining means. . The first mobile terminal further includes determination means for determining whether or not the position coordinates have been received from another mobile object to be collided, and the transmission means has the determination means as a collision target. When it is determined that position coordinates have not been received from another moving body, the position coordinates of the current position detected by the first detection means are transmitted without transmitting the plurality of position coordinates.

  In addition, the mobile terminal of the present invention is provided in each mobile body, and performs collisions between mobile bodies based on position information of each mobile body that is directly transmitted and received when the separation distance between the mobile bodies is a predetermined distance or less. A mobile terminal for alarming, detecting means for detecting the position coordinates of the current position of the mobile body, and transmitting a plurality of position coordinates indicating the movement progress of the mobile body based on a detection result of the detection means First determination for determining a current position on the road of the map information of the mobile body based on the transmission means, the storage means for storing the map information, the position coordinates detected by the detection means and the map information Means, receiving means for receiving a plurality of position coordinates transmitted from another moving body, and based on the plurality of position coordinates and the map information received by the receiving means, Determine the current position on the road Determining means for determining the possibility of a collision based on the current position of the moving body determined by the first and second determining means, the current position of the other moving body, and the map information; And a warning means for warning a collision when the judgment means judges that there is a possibility of a collision.

  According to the present invention, by transmitting a plurality of position coordinates indicating the progress of movement from the transmission side, the misrecognition of the current position of the transmission side moving body is reduced, and the road on which the transmission side moving body is moving Can be reliably detected, and a collision warning with a mobile unit on the transmission side can be executed with high accuracy. In other words, even if the position accuracy of the current position deteriorates, a plurality of position coordinates are obtained from the transmitting side, and the current position on the new side is obtained by mapping processing on the receiving side, so that the collision warning can be executed with high accuracy. it can.

  According to the second aspect of the present invention, by transmitting position coordinates detected in the vicinity of at least one of a branch point, a curve, or a merging point, with a small number of position coordinates, The collision warning can be executed with higher accuracy.

  According to the invention according to claim 3, by transmitting the number of past position information according to the density of surrounding roads, it is possible to reliably detect the road on which the mobile body on the transmitting side is moving, By matching the possibility of collision with the amount of data to be transmitted, it is possible to accurately execute a collision warning with the transmitting-side moving body with more effective transmission.

    According to the fourth aspect of the present invention, when there is no reception from the vehicle to be collided, a plurality of position coordinates are not transmitted, so that the collision warning with the transmitting-side moving body is accurate while eliminating unnecessary transmission. Can perform well.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the relative arrangement of components, the display screen, and the like described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.

  In the following embodiments, a vehicle is described as an example of a moving body. However, a technique for performing an alarm for preventing a collision of a plurality of moving bodies can be applied to another moving body, a ship, an airplane, a person, and the like. Therefore, the same effect can be achieved and is included in the present invention.

<Configuration example of collision alarm system for moving body of this embodiment>
In FIG. 1, the structural example of the collision alarm system for moving bodies of this embodiment is shown. Although FIG. 1 shows a system comprising two vehicles having a map matching function and capable of collision warning, a system comprising a vehicle having a map matching function and a vehicle that does not, a vehicle capable of collision warning and a vehicle that is not capable of collision warning. Or a combination thereof. In practice, as shown in FIG. 5, the number of vehicles that transmit position information to the receiving vehicle 40 is not one, but there are a plurality of vehicles, and FIG. 1 shows only one of them. Note that the map matching in the present embodiment includes a function of specifying the road on which the vehicle is moving from the position coordinates of the vehicle and the map information. The position information used below is basically the position coordinates of the vehicle.

  In FIG. 1, 10a and 10b are ECUs for controlling the vehicle. The ECU is composed of a CPU for arithmetic processing, a ROM for storing fixed data and programs, a RAM for temporarily storing data and programs, and the like. 11a and 11b are various sensors necessary for control of the ECUs 10a and 10b, and sensors such as engine control are included. Sensors used in the collision alarm processing of this example are vehicle speed sensors, brake switches, turn signal switches, and the like. It is. Reference numerals 12a and 12b denote GPS / navigation systems that detect vehicle position information. The GPS / navigation systems 12a and 12b store map information.

  13a and 13b are information providing units including an image output unit and an audio output unit that provide navigation information and perform a collision warning in this example, and in this example have an alarm unit as a part thereof. Reference numerals 14a and 14b denote transmission / reception data storage units for storing data to be transmitted / received by inter-vehicle communication, and may be shared with the RAMs of the ECUs 10a and 10b. A configuration example of the transmission / reception data storage units 14a and 14b in this example will be described below with reference to FIG.

  Reference numerals 15a and 15b denote inter-vehicle communication units capable of inter-vehicle communication at a short distance, for example, 200 m. Any method may be used for such inter-vehicle communication. However, if a simple method is used, a fixed-length method is preferable for transmission data, and a variable-length method is preferable if the amount of transmission data is to be reduced. These selections are selected in relation to communication capability, ECU processing capability, and the like. In this embodiment, as will be described later, the transmission data amount is changed according to the density of the surroundings, or the transmission data amount is changed depending on whether there is reception from the collision target vehicle. The method is preferred.

<Configuration example of transmission / reception data storage unit>
FIG. 2 is a diagram illustrating a configuration example of the transmission / reception data storage units 14a and 14b. FIG. 2 shows only data that is directly used in the processing of this embodiment, but other data can be transmitted and received. Further, since the received data is the same as the transmitted data, details are not shown. Note that a mobile unit having only a function of transmitting data does not require a reception data storage area, whereas a mobile unit having only a function of receiving data and issuing a collision warning does not need a transmission data storage area.

  21 is a storage area for storing the vehicle state quantity of the host vehicle. In this example, for example, the position (latitude and longitude) 211 of the own vehicle detected by GPS, the vehicle speed 212 obtained from the vehicle speed sensors of the various sensors 11a and 11b, the vehicle orientation sensor or the vehicle obtained from the movement of the position. The direction 213 and the like are stored. Note that the position (latitude, longitude) 211 of the host vehicle may be position information obtained by further map-matching information detected by GPS based on map information.

  Reference numeral 22 denotes a storage area for storing the operation state of the driver of the host vehicle. In this example, for example, a brake signal 221 indicating whether or not the brake is stepped on, a blinker signal 222 indicating whether the blinker is blinking, right or left, and the like are stored.

  Reference numeral 23 denotes a storage area for storing a history of a plurality of position information detected in the past. In FIG. 2, a plurality of pieces of position information from position information (-1) to position information (-n) are stored (-n represents the nth position information in the past).

  The plurality of pieces of position information are not continuously detected position information but past characteristic position information, for example, position information corresponding to a bent portion, for example, a branching point, a curve or a merging point of a road. It is more preferable if position information useful for recognizing the current position of the vehicle on the transmission side is selected and stored. In addition, since past position information is usually held for map matching, a configuration in which it is selected and transmitted may be used.

  In the example of FIG. 7, for example, position information 72a, 72b, 72c, 72d and the like are stored. If the position information 72a, 72b, 72c, 72d is received, the receiving vehicle can recognize that the transmitting vehicle is traveling on the road 74, and misrecognize that the transmitting vehicle is on the road 75. Disappear.

  In addition, the number of position information that can characterize the road on which the vehicle has traveled, for example, five, is stored and transmitted. Further, as described below, it is preferable to reduce the communication load by determining the congestion degree of the road near the current position and performing control so that the number corresponding to the congestion degree is transmitted. For example, in a city center with a high degree of congestion, a large amount of position information is sent, and in the countryside with a low density, only the current position is sufficient.

  Note that the transmission data shown in FIG. 2 is an example, and may include other information with which each intersection position or arrival time at the intersection can be recognized or calculated more accurately. For example, a road situation (for example, congestion situation) in front of the host vehicle may be considered.

<Operational Example of Collision Warning System for Moving Object of this Embodiment>
Hereinafter, the operation example by the structure of the collision alarm system for moving bodies of the said embodiment is demonstrated.

  FIG. 3 is a flowchart showing an example of an operation procedure of the moving object collision warning system of the present embodiment. In the following description, the left side of FIG.

  On the transmission side, the vehicle position is detected by GPS in step S31. This vehicle position may be further map-matched using map information. The own vehicle position detected in step S32 is stored in the transmission / reception data storage unit 14a. As described above with reference to FIG. 2, such storage is preferably performed by selecting and storing characteristic position information such as a bent portion rather than storing continuously detected vehicle positions. In step S33, the density of roads around the current position is determined. As the degree of congestion, for example, the number of roads within a radius of 200 m from the own vehicle, the road area, and the like can be considered. This density information is used to determine the number of pieces of position information at the time of data transmission.

  In step S34, it is determined whether or not there is reception from the vehicle to be collided. An example of simple determination is to determine reception from another vehicle (that is, there is another transmission vehicle within a radius of 200 m from the own vehicle). As an example of excluding reception from a vehicle that is not a collision target, there is an example of excluding reception from a preceding vehicle on the same road as the host vehicle. Furthermore, it is possible to determine whether or not it is a collision target, but if a complicated determination is made, the processing speed may be reduced and necessary transmission may be eliminated. That's fine.

  If there is reception from the vehicle to be collided, a plurality of past position information is selected as transmission data in step S35. In addition, although the example which selects and memorize | stores characteristic position information in the said step S32 was shown, it memorize | stores continuously in step S32, and characteristic position information is selected based on the change of a position coordinate in step S35. May be. If there is no reception from the vehicle to be collided, the current position detected in step S36 is selected as transmission data. Note that the storage of other transmission data is omitted. Here, it is assumed that preparation of transmission data as shown in FIG. 2 is completed.

  In step S37, the transmission data selected in step S35 or S36 is transmitted. This transmission does not determine the transmission partner, but broadcasts to an unspecified number of other parties existing in, for example, a 200 m square.

  Note that the transmission in step S37 is, for example, every 100 ms. In the flowchart of FIG. 3, the transmission side is described as a loop, which is a schematic diagram. Actually, there is a procedure of inserting a subroutine in the middle of other control or measuring 100 ms. Here, it is not shown in order to avoid complexity. Further, the number of pieces of position information to be transmitted is determined in accordance with the density of roads around the current position.

  On the receiving side, first, in step S41, the vehicle position is detected by GPS and stored in the transmission / reception data storage unit 14b. In step S42, it is determined whether or not there is reception. If there is no reception, the process proceeds to the next process. If there is reception, the data including the position information, speed, brake state, etc. transmitted in step S43 is received and stored in the transmission / reception data storage unit 14b. In FIG. 3, only one transmission-side vehicle is illustrated, but reception is performed from a plurality of vehicles within a 200 m range.

  In step S44, it is determined whether or not the received data includes a plurality of pieces of position information. If there is a plurality of pieces of position information, in step S45, the plurality of pieces of position information are used as a past history, and the same high-precision map matching as that of the own vehicle is performed to obtain the current position of the transmitting vehicle. If the received data does not include a plurality of position information, simple map matching is performed in step S46 to obtain the current position of the transmitting vehicle.

  In step S47, it is determined whether or not a collision warning is necessary based on the current position of the transmitting vehicle obtained in step S45 or S46 and the current position of the host vehicle. This determination is made from, for example, a time difference that takes the vehicle speed into account when the vehicle passes through the same intersection or the difference in arrival time at the intersection is within a predetermined time.

  FIG. 4 shows a detailed flowchart of an example of alarm determination in step S47.

  First, in step S401, the current position of the host vehicle is specified by map matching, and the intersection position in the traveling direction of the host vehicle and the arrival time at each intersection are calculated. Based on the current position of the other vehicle obtained in step S45 or S46, it is determined whether the other vehicle passes the same intersection as the intersection calculated in step S401. If there is not the same intersection, it will progress to step S406 and it will be determined whether there exists the other vehicle which has not performed collision determination, and if there exists, it will return to step S401 and the relationship with the next other vehicle will be checked.

  If the target other vehicle passes the same intersection, the process proceeds to step S403, and the arrival time of the other vehicle at the intersection is calculated from the position information and the speed. In step S404, the arrival times of the other vehicle and the host vehicle are compared to determine whether or not the difference between the arrival times is less than a predetermined threshold value Th. If the difference in arrival time is larger than the threshold value Th, it is determined that there is no possibility of collision, and the process proceeds to step S406. If it is less than the threshold value Th, alarm information is created in step S405.

  In determining whether or not there is an intersecting intersection in step s402, first, if there is no possibility of meeting at the same intersection from the position and speed of another vehicle, the other vehicle is processed to be omitted. Desirable in terms of speed. For example, if the host vehicle is the vehicle 50 in FIG. 5, it is desirable that the vehicle behind the vehicle 50 (not shown) (downward in the drawing) is basically deleted from the collision target vehicle although it is related to the speed. Further, it is desirable that the vehicle 58 or 60 is also deleted when the traveling roads are different and there is no possibility of collision when traveling straight on the traveling roads. Also, the vehicles 53 and 59 shown in FIG. 5 are vehicles that are traveling in the same direction on the same road, and there is no possibility of encounter collision in this example. In this case, it may be deleted. Moreover, since it is the intersection B with a signal that the vehicles 51 and 52 may meet the host vehicle 50, this may be deleted. Further, for example, when the vehicle 51 is making a turn signal for turning left or right, or when the vehicle 52 is making a turn signal for turning left, there is no possibility of encounter collision, so this case may be deleted. Furthermore, it is possible to determine that there is no possibility of encounter collision based on information such as left turn or right turn prohibition from map information, or information on roads with many lanes or roads with separation zones. The above example is a few examples of the condition of the intersection to be deleted, and various other conditions can be considered. The determination of the possibility of collision of these encounters is determined from the relationship between the accuracy of the alarm and the burden on the ECU in relation to the comparison and calculation of arrival times.

  In step S403, the arrival time is calculated from the current position and speed. However, the arrival time may be calculated more accurately based on data such as other vehicle conditions of other vehicles, driver operations, and road conditions.

  Returning to FIG. 3, in step 48, it is determined whether or not to issue an alarm from the determination result in step S <b> 47.

<Specific example of collision warning>
FIG. 6 shows an example when the collision warning is performed on the screen. FIG. 5 is an example of a bird's-eye view of road conditions when the host vehicle is the vehicle 50. In FIG. 5, 51 to 60 are other vehicles within a radius of 200 m from the vehicle 50, and A to G are intersections. There are signals at intersections A and B.

FIG. 6 is an example of a collision warning output on the navigation screen in the vehicle 50 of FIG. Within 200 m ahead of the traveling road of the vehicle 50, there are intersections F, D, and B in the traveling order. Among these, the vehicle 57 from the right and the vehicle 56 from the left are met at the intersection F, and the vehicle 54 is met from the right at the intersection D. At the intersection B, the vehicle 51 from the left and the vehicle 52 from the right meet, but there is a signal at the intersection B, so it is not displayed.

In FIG. 6, the entire area within 200 m ahead of the road is displayed. However, when the host vehicle speed is low, it is useless to display up to 200 m, and each display becomes fine and difficult to see. For example, when the speed of the host vehicle is low, a position reached a predetermined time ahead (for example, 9 seconds or 10 seconds ahead) may be displayed.

  Although the present invention is not an invention relating to the way of alarming, it will not be described in detail, but for example, it is possible to display it in an identifiable manner according to the difference in possibility of collision or urgency. For example, the distance to the intersection, the speed and braking state of other vehicles, the left and right directions on a wide road, and the like are conditions for judging the possibility and the urgency.

  Further, the collision warning is not limited to the screen display, and for example, in the case of high urgency, other methods such as warning by sound or vibrating the seat are possible.

<Other embodiments>
In the above-described embodiment, a system has been described in which both the own vehicle and other vehicles have a function of transmitting a plurality of position information, and can perform a collision alarm with each other. However, a vehicle in which a collision alarm is not possible only by transmitting a plurality of position information It is possible to receive a collision alarm by receiving multiple position information, but it is not bidirectional, such as a vehicle that does not have the function of transmitting multiple position information, or a vehicle that can use transmission / reception information for a collision alarm and a vehicle that cannot It can be unidirectional. The present invention also includes these.

It is a figure showing an example of composition of a collision warning system concerning this embodiment. It is a figure which shows the structural example of the transmission / reception data storage part of FIG. It is a flowchart which shows the operation example of the transmission side vehicle and the receiving side vehicle in the collision warning system which concerns on this embodiment. It is a flowchart which shows the detail of warning determination (S47) of FIG. It is a bird's-eye view of a road situation for explaining operation of a collision warning system concerning this embodiment. It is a figure which shows the example of a display of the collision warning which concerns on this embodiment. It is an overhead view of the road condition for demonstrating the conventional problem.

Claims (5)

A first mobile terminal included in the first mobile body, and a second mobile terminal included in the second mobile body, the first mobile terminal being separated from the second mobile terminal An alarm system that warns of a collision between the first and second moving bodies based on position information of the moving body that is directly transmitted and received when the distance is equal to or less than a predetermined distance,
The first mobile terminal is
First detection means for detecting position coordinates of a current position of the first moving body;
Transmission means for transmitting a plurality of position coordinates indicating the progress of movement of the first moving body based on the detection result of the first detection means;
The second mobile terminal is
Storage means for storing map information;
Second detection means for detecting position coordinates of a current position of the second moving body;
First determination means for determining a current position on the road of the map information of the second moving body based on the position coordinates detected by the second detection means and the map information;
Receiving means for receiving the plurality of position coordinates transmitted from the transmitting means;
Second determining means for determining a current position on the road of the map information of the first moving body based on the plurality of position coordinates and the map information received by the receiving means;
Determination means for determining the possibility of collision based on the current position of the first moving body, the current position of the second moving body, and the map information determined by the first and second determining means. When,
An alarm system comprising: an alarm unit that issues an alarm of a collision when the determination unit determines that there is a possibility of a collision. In the vicinity of at least one of a branch point, a curve, or a merging point on the road on which the first moving body has moved, based on the position coordinates detected by the first detection unit, by the first moving body terminal. Selecting means for selecting the position coordinates detected in
The alarm system according to claim 1, wherein the transmission unit transmits the position coordinates selected by the selection unit. The first mobile terminal further comprises:
Storage means for storing map information;
A discriminating unit for discriminating a density of a road around the current position of the first moving body based on the position coordinates detected by the first detecting unit and the map information;
3. The alarm system according to claim 1, further comprising a setting unit configured to set the number of the plurality of position coordinates transmitted by the transmission unit based on the density determined by the determination unit. . The first mobile terminal further comprises determination means for determining whether or not position coordinates have been received from another mobile object to be collided with,
The transmission means detects the first detection means without transmitting the plurality of position coordinates when it is determined that the determination means has not received position coordinates from another moving object to be collided. The alarm system according to any one of claims 1 to 3, wherein the position coordinates of the current position are transmitted. Each mobile unit is provided with each mobile unit, and is a mobile terminal that warns a collision between mobile units based on position information of each mobile unit that is directly transmitted and received when the separation distance between the mobile units is a predetermined distance or less,
Detecting means for detecting the position coordinates of the current position of the mobile body;
Based on the detection result of the detection means, a transmission means for transmitting a plurality of position coordinates indicating the movement progress of the mobile body;
Storage means for storing map information;
First determining means for determining a current position on the road of the map information of the mobile body based on the position coordinates detected by the detecting means and the map information;
Receiving means for receiving a plurality of position coordinates transmitted from another moving body;
Second determining means for determining a current position on the road of the map information of another moving body based on the plurality of position coordinates and the map information received by the receiving means;
Determination means for determining the possibility of collision based on the current position of the own mobile body determined by the first and second determination means, the current position of the other mobile body, and the map information;
A mobile terminal comprising: an alarm unit that issues an alarm of a collision when the determination unit determines that there is a possibility of a collision.

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