JP2008131520A - Mobile object monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To monitor a mobile station by finding its position in an arbitrary monitored area at any arbitrary time, improve radio wave use efficiency, and construct a system with a simple apparatus. <P>SOLUTION: The each mobile station finds its own position by a positioning means, receives an interrogation signal sent from a control station, reads a response allowed area included in the interrogation signal, and sends a response signal including an identification code of its own station to a time slot corresponding to a spatial slot of the own station in the response allowed area when the mobile station enters the response allowed area. After sending the interrogation signal including the response allowed area, the control station receives the response signal from the mobile station and find the position of the mobile station according to the time slot. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile monitoring system that includes a control station and a mobile station that monitor the position of the mobile station and the like, and monitors the mobile station at the control station.

  For example, when a ship is monitored in a congested area such as a bay, an AIS (Automatic Identification System) is conventionally used. Patent Document 1 discloses a time division multiplex communication system suitable for ship operation management.

  In this time division multiplexing communication system of Patent Document 1, a radio wave modulated by transmission data is transmitted to a master station in each individual time slot synchronized with a reference timing signal generated by reception of radio waves from GPS satellites by a plurality of slave stations. The master station receives radio waves from each slave station and extracts transmission data from each slave station for each time slot.

  Here, the entire configuration of the time division multiplexing communication system of Patent Document 1 is shown in FIG. In FIG. 1, the information center is geographically provided, for example, at a position adjacent to an area where large-scale offshore construction is performed, and performs time division multiplex communication with a work ship performing various construction work. Downlink data from the information center to work ships includes information specifying work ships such as entry order, entry / exit instructions, and operational status confirmation, as well as weather / sea state information, safety information, construction area information, soil source information, etc. It is information common to work vessels, and uplink data from the work vessel to the information center is information for each work vessel such as an identification number, a current position, a course, a speed, and an operation status.

Even in the case of the AIS and the system disclosed in Patent Document 1, the data transmitted from the mobile station to the control station includes the position information of the mobile station.
JP-A-11-160411

  However, in AIS, each mobile station voluntarily transmits navigation information including its own ship position information. Therefore, the control station receives AIS data from a plurality of mobile stations, and each movement included in the data is transmitted. The position information of the station is read out, and it is first determined whether or not the position exists in the monitoring area. Therefore, it is necessary to receive a signal from a mobile station existing at a position that is not a monitoring target each time and determine whether or not the mobile station is a monitoring target. In particular, in a congested area, a large number of AIS data must be processed, and there is a problem that the data processing amount becomes larger than the information amount to be handled.

  In general, the moving object to be monitored is not uniformly present in the space. Rather, the existence probability (function) has a large dynamic range. For example, ships are congested on quays, bays, straits, etc., but are offshore offshore. In the monitoring method using a conventional system such as AIS, the resolution is uniform (uniform and unchangeable) and does not support this large dynamic range, so it must be a very inefficient search.

  In addition, since AIS automatically transmits navigation information at predetermined time intervals for each mobile station, the location information of each mobile station is required for the control station to obtain location information of the mobile station at an arbitrary time. There is a problem that the position of the mobile station at an arbitrary time cannot be obtained directly and the amount of calculation increases.

  It is possible to configure the mobile station to perform predetermined data transmission between the control station and the mobile station by using a polling method instead of the method in which the mobile station transmits spontaneously. The response signal is transmitted and received, and there is a problem that the use efficiency of radio waves is lowered. There is also a problem that the protocol cannot be simplified and the scale of the apparatus increases.

  On the other hand, in the time division multiplex communication system disclosed in Patent Document 1, unlike the polling method, there is no need to solicit transmission from the master station to the slave station, and time division is performed in time slots synchronized between the master station and the slave station. Data can be collected from a large number of slave stations within a limited amount of time in order to transmit data, but selective monitoring is performed for mobile stations that exist in any monitoring area defined by the control station. I can't. Further, there is an upper limit to the number of time slots that can be set, and it is impossible to monitor a slave station exceeding that number.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described various problems and to obtain and monitor the position of a mobile station existing in an arbitrary monitoring area at an arbitrary time. It is providing the mobile body monitoring system which can be comprised by.

The mobile monitoring system of the present invention is composed of a mobile station and a control station.The mobile station receives positioning means for obtaining position information of the own station and a question signal transmitted from the control station, and from the question signal, Response permission area information specifying a response permission area that is a response permission area is extracted, and when the position of the local station obtained by the positioning means is within the response permission area, a response is made based on the position within the permission area. Response time transmitting means for determining a time slot to be determined and wirelessly transmitting a response signal in the time slot,
Question signal transmitting means for wirelessly transmitting an inquiry signal including the response permission area information to the control station, and the position of the mobile station according to the time slot that receives the response signal from the mobile station and receives the response signal Mobile station position detecting means for obtaining

  The “time slot” is a generation timing at which a response signal can be taken, and here is a relative time based on the generation time of the question signal.

The mobile monitoring system of the present invention comprises a mobile station and a control station. The mobile station receives positioning information for obtaining position information of the mobile station and a question signal transmitted from the control station, and receives the question signal. From the response permission area information that specifies a response permission area that is a response permission area, and when the position of the local station obtained by the positioning means is within the response permission area, based on the position within the permission area A response signal transmitting means for defining a time slot and wirelessly transmitting a response signal after a time slot from the reception time of the interrogation signal,
A question signal transmitting means for wirelessly transmitting an inquiry signal including the response permission area information to the control station, and receiving the response signal from the mobile station, until receiving the response signal from a transmission time of the question signal Mobile station position detecting means for obtaining the position of the mobile station corresponding to the time slot corresponding to the time.

  In the mobile monitoring system of the present invention, the mobile station according to the time slot is designated by specifying a position in the response permission area corresponding to the time slot at which the response signal is received as a new response permission area. The response permission area setting means for increasing the position resolution and transmitting the question signal again by the question signal transmission means is provided.

  In the mobile monitoring system of the present invention, the control station determines a position in the response permission area corresponding to a time slot corresponding to a time slot in which the carrier of the response signal can be detected and the response signal cannot be decoded. And a response permission area setting means for increasing the position resolution of the mobile station according to the time slot and transmitting the question signal again by the question signal transmission means.

  In the mobile monitoring system of the present invention, the time slot corresponds to a corresponding area when the response permission area is divided into a plurality of equally spaced areas according to two-dimensional coordinates or three-dimensional coordinates.

  In the mobile monitoring system of the present invention, the control station includes means for including in the interrogation signal a command indicating a type of information requested to be reported to the mobile station, and the mobile station responds to the command according to the command. A means for including information in the response signal is provided.

According to the present invention, the following effects can be obtained.
(1) Since the control station designates a response permission area as a condition for permitting a response, only the response signal from the mobile station within the response permission area can be received, and wasteful data traffic is suppressed, and radio wave use efficiency is improved. Rise.

  In addition, since the space existence probability of the moving object to be monitored has a large dynamic range, it is possible to cope with it, and the search efficiency of the moving object in the monitoring area is very high.

(2) The control station can obtain the position information of the mobile station at an arbitrary time, and an operation for estimating the position of the mobile station at a predetermined time is unnecessary, and the scale of the system does not increase.

(3) Rather than assigning a predetermined time slot to the mobile station, the position of the mobile station corresponds to the time slot, so there is no problem due to the time slot allocation being used up.

(4) Since the mobile station does not need to put its own location information on the response signal, the data length of the response signal is shortened and the radio wave utilization efficiency is increased.

  Further, according to the present invention, the control station transmits a question signal by designating a position in the permission area corresponding to the time slot that received the response signal as a new response permission area, thereby moving according to the time slot. The station position resolution can be increased. For example, the position of the mobile station can be obtained efficiently and with high resolution by transmitting a small number of interrogation signals by sequentially narrowing the response permission area.

  When there are a plurality of mobile stations in a position within the response permission area corresponding to a certain time slot, a collision occurs because these mobile stations transmit response signals in the same time slot. This state is when the carrier can be detected and the response signal cannot be decoded. According to this invention, by specifying the area within the response permission area corresponding to the time slot in which the carrier of the response signal could be detected and the response signal could not be decoded as a new response permission area, and transmitting the question signal again. The response signal from the mobile station can be received with high resolution. Further, by sequentially narrowing the response permission area, the response signal from each mobile station can be individually decoded, and the position information of each mobile station can be obtained. Compared with the case where the interrogation signal is transmitted with the position resolution increased from the beginning, the total data amount of the interrogation signal and the response signal can be reduced, and the radio wave use efficiency is increased. Further, the total number of time slots is reduced, and the mobile station position information and other information can be collected in a short time.

  Further, according to the present invention, each movement is determined by defining the time slot so as to correspond to a corresponding area when the response permission area is divided into a plurality of equally spaced areas according to two-dimensional coordinates or three-dimensional coordinates. The station and the control station can simply convert the correspondence between the time slot and the position (area) of the mobile station, enabling efficient calculation.

  Further, according to the present invention, the control station includes a command indicating the type of information requested to report to the mobile station in the question signal, and the mobile station includes command response information corresponding to the command in the response signal, The control station can request not only the position information of the mobile station but also a report on the course and speed, for example, and obtain the answer from the mobile station. Therefore, a system capable of collecting and monitoring mobile station information at an arbitrary time of mobile stations existing in an arbitrary monitoring area can be configured with a simple device without lowering radio wave use efficiency.

<< First Embodiment >>
FIG. 2 is a block diagram showing the configuration of the moving object monitoring system according to the first embodiment. This mobile body monitoring system comprises one control station 10 and a plurality of mobile stations 20A, 20B. The control station 10 is provided, for example, on the rooftop of a building overlooking the bay where a predetermined monitoring area exists. Further, the mobile stations 20A, 20B and the like are provided in a ship which is a moving body.

  The control station 10 has an interrogator (interrogator) 11 that transmits a predetermined interrogation signal, its antenna 12, an operation / display terminal 15 that controls and displays the operation of the control station 10, and an accurate time or time passage. A positioning receiver 13 for receiving a signal used in a positioning system such as GPS, GLONASS, GALILEO or the like and an antenna 14 thereof are provided.

  Each mobile station receives the interrogation signal from the control station 10 and transmits a predetermined response signal, a transponder (responder) 21 and its antenna 22, and a positioning receiver 23 for positioning the position of the mobile station (own station). And an antenna 24 for the same. The positioning receiver 23 receives positioning signals such as GPS, GLONASS, GALILEO, and obtains reception point position information.

  FIG. 3 shows the format of the interrogation signal and response signal. As shown in FIG. 3A, the question signal transmitted from the control station 10 includes a “synchronization signal”, “question index”, “response permission area”, and “error correction code”. Since the question signal can be regarded as one sentence in this way, it can also be called a “question sentence”.

“Synchronization signal” is a signal for bit / character / frame synchronization of communication.
The “question index” is a code embedded in the question signal in order to confirm the responsive relationship between the question signal and the response signal. When the mobile station transponder responds to this interrogation signal, it embeds the same code as the interrogation index in the response signal, so the control station interrogator uses the response signal received from the interrogator itself as the response signal. Used to identify whether or not there is. For example, when there is only one interrogator in the monitoring area, the question index is not necessary when this responsive relationship can be reliably ensured or does not need to be ensured. On the contrary, the above question index is effective when it is desired to reduce false detection in the interrogator due to erroneous response of the transponder.

  The “response allowed area” is information for designating an area (an area that the control station wants to inquire) for allowing a response from the mobile station. Further, the “error correction code” is information for error correction detection such as a checksum, and the mobile station performs error correction of the interrogation signal using this error correction code.

  As shown in FIG. 3B, the response signal transmitted by the mobile station includes a “synchronization signal”, “response index”, “identification code”, and “error correction code”. Since the response signal can be regarded as one sentence in this way, it can also be called a “response sentence”.

Here, the “synchronization signal” is a signal for communication bit / character / frame synchronization.
The “response index” has the same sign as the question index included in the question signal when responding to the question signal. As already described, the interrogator of the control station is used to identify whether or not the received response signal is a response signal to the interrogation signal issued by itself.

“Identification code” is a solid identification code assigned to each mobile station. The control station identifies the mobile station (mobile body) by extracting this identification code. The “error correction code” is information for error correction detection such as a checksum. The error correction code causes the control station to perform error correction of the response signal and detect whether decoding is successful.
The response signal does not include the position information of the mobile station (own station).

  If the interrogator and the transponder have other means for synchronizing without depending on the synchronization signal in the interrogation signal and the response signal, this synchronization signal is unnecessary. For example, the interrogator and the transponder may be synchronized by treating a reference time signal of a positioning system such as GPS as a synchronization signal.

  FIG. 4 is a diagram showing the relationship between the response permission area and the space slot corresponding to the time slot. Here, the two-dimensional coordinate system of (latitude, longitude) is represented by an orthogonal coordinate system. In this example, the information of the response permission area is given as the base point BP (base point) at the upper right of the rectangular area shown in FIG. 4A, and is given by (latitude, longitude) of this starting point BP. For example, (123.4E, 67.89N). And assuming latitude and longitude in units of 0.001 degrees (resolution of 0.001 degrees), a total of 100 areas, 10 units each in the west and south directions, as shown in FIG. A space slot of 00 to 99 with the main scan and the west direction as the sub scan is given. Therefore, when BP is (123.45E, 67.89N), the slot of the space slot “18” corresponds to the position as shown in FIG.

  The information of the response permission area includes the BP (latitude, longitude) data and latitude / longitude resolution (0.001 degree) information corresponding to one space slot. For example, when (latitude, longitude) exists in the area shown in FIG. 4B, a response signal is transmitted at a timing corresponding to the space slot 18. When the control station receives a response signal at the timing of this spatial slot 18, the identification code is extracted from the response signal to identify the mobile station, and the position (area) corresponding to the spatial slot 18 is determined for the mobile station. Obtained as the position (area where the mobile station exists).

  In the above example, the information of the response permission area includes the resolution information of latitude / longitude corresponding to one space slot, but the minimum digit of each axis (latitude, longitude) of the response permission area information is changed. If 1/10 (or 1/100 or the like) is determined in advance as a standard so as to be understood as the resolution, it is not necessary to transmit the resolution information itself.

  FIG. 5 is a diagram showing two examples of response scheduling of a mobile station that responds to an inquiry signal from a control station. In FIG. 5A, Q indicates an interrogation signal and its time slot, and A18 indicates a response signal and its time slot transmitted corresponding to the spatial slot 18 shown in FIG.

  In this example, the question signal Q is transmitted in T1 for 1 second from 12:34:00. After that, the interrogation signal transmission guard time T2 (9 seconds) is waited, and thereafter, the all-station response time T3 (100 seconds) from the time slot 00 to 99 continues. Therefore, the response signal A18 corresponding to the space slot 18 is transmitted from 12:34:28 to 1 second.

  The mobile station transponder takes time to receive the interrogation signal from the interrogator of the control station, to perform the decoding (decoding) calculation, and to prepare for the transmission of the response. The guard time T2 is for ensuring time for such preparation. Therefore, the transmission guard time T2 may be longer than the maximum time required for the response slot determination (scheduling) process of the transponder itself.

  This response scheduling is executed in units of seconds synchronized with the time of the GPS positioning system. That is, the interrogator 11 of the control station and the transponder 21 of the mobile station operate in synchronism with the GPS positioning system time determined by the GPS receivers 13 and 23.

  In this example, a rectangular area whose diagonal is from (123.45E, 67.89N) to (123.44E, 67.88N) is detected with a resolution of 0.001 degree in 110 seconds (1 + 9 + 100 = 110). Can do.

  In other words, the position of the mobile station can be obtained from the time slot based on the transmission time of the inquiry signal Q. Since this time slot is the elapsed time from the transmission time of the inquiry signal Q from the control station (= the reception time for the mobile station) to the reception time of the response signal A18 (= the transmission time for the mobile station), the control station Can detect the time slot based on the transmission time of the interrogation signal transmitted by itself and the reception time of the response signal, and can determine the position of the mobile station based on the time slot.

  FIG. 5B shows an example in which the time at which the interrogation signal Q is transmitted is fixed in advance to an even minute minute (a time in which the digits after the second are 0 and the minute digits are even). The all-station response time T3 is 100 seconds as in the case of FIG.

  When the generation timing of the question signal is fixed as described above, it is not necessary to refer to the transmission / reception time of the question signal, and the second value can be directly used as the time slot number. The mobile station may regard the value of the second digit of the current time as the time slot number and transmit the response signal to the time slot to which the response signal should be transmitted. Further, the control station may determine the position of the mobile station corresponding to the time slot by regarding the value of the second digit of the time when the response signal is received as the time slot number.

  In the example shown in FIGS. 4 and 5, when a plurality of mobile stations exist in an area corresponding to a certain slot, the mobile stations transmit a response signal at the timing of the slot corresponding to the area. Therefore, signal collision occurs, and the control station cannot decode the response signal. However, the presence of a carrier can be detected. Therefore, the problem of signal collision is avoided by the following procedure.

  (1) The control station detects that there are a plurality of mobile stations at a position corresponding to the space slot based on two points: the presence of a carrier and the inability to decode the response signal.

  (2) If it is found that there are a plurality of mobile stations at a position corresponding to one spatial slot, an inquiry signal is transmitted with higher resolution only for the area corresponding to the spatial slot, and responses from the plurality of mobile stations Receive a signal. If the resolution is sufficient, a plurality of mobile stations can be detected individually.

  (3) If the resolution is still insufficient, the state is the same as in (1) above, so a finer (higher) resolution is set and the question signal is transmitted again.

  By repeating the above processing, it becomes possible to detect the positions of any mobile stations.

  FIG. 6 is a diagram showing an example of the above process. In FIG. 6 (A), as in the case of FIG. 4 (A), the response permission area of the starting point BP1 is determined with a resolution of 0.001 degrees for both the latitude and longitude of one space slot. FIG. 6B shows the transmission timing of the interrogation signal and the response signal on the time axis, Q1 is the interrogation signal and its time slot, and A1_13_1 and A1_13_2 are each transmitted from two mobile stations. Each response signal and its time slot are shown. A1_30 indicates a response signal transmitted from a certain mobile station and its time slot.

  In this example, the response signal can be correctly decoded in the time slot 30, but the carrier can be detected and the response signal cannot be decoded in the time slot 13.

  Accordingly, the upper right point BP2 of the space slot 13 is set as a new starting point, and the latitude / longitude of one slot is determined to have a resolution of 0.0001 degrees as shown in FIG. 6C. That is, the slot fineness is set to 10 times (resolution is 1/10).

  FIG. 6D shows the transmission timing of the interrogation signal and the response signal on the time axis, Q2 is the interrogation signal and its time slot, and A2_12 and A2_28 are the responses transmitted from the mobile station, respectively. Signal and its time slot. By increasing the resolution in this way, the response signals from the two overlapping mobile stations are transmitted in different slots 12 and 28, respectively, and the control station can receive each independently and identify the two mobile stations. Become.

  7 and 8 are flowcharts showing the processing of the interrogator 11 and the operation / display terminal 15 of the control station 10 shown in FIG. FIG. 7 shows the processing procedure of the control station. First, an initial value of resolution is set, and further, (latitude, longitude) of the base point BP of the response permission area is set. Thereafter, the moving body monitoring process described below is performed.

  In this embodiment, the number of slots is fixedly determined so that the spatial slot takes a value of 00 to 99 (total of 100 slots) at any resolution, but this may be variable. In that case, the data of the number of slots in the latitude direction and the longitude direction may be included in the response permission area information.

  FIG. 8 is a flowchart showing the detailed contents of the moving object monitoring process. First, a question signal (question sentence) is created based on the parameters and transmitted (S1 → S2). Thereafter, a 9-second guard time is waited (S3), and an initial value “00” of the time slot number is set (S4).

  Subsequently, the presence / absence of a carrier in the time slot is determined. If there is a carrier, the response signal is decoded (S5 → S6 → S7). If the decoding is successful, the position of the mobile station is obtained and stored based on the time slot number, resolution, and base point BP of the response permission area (S9).

If the response signal cannot be decoded even if the carrier exists, the time slot (collision slot) number is temporarily stored (S8 → S12).
The above processing is sequentially performed for all time slots (S10 → S11 → S5 →...).

  Thereafter, if the collision slot exists, the base point BP2 of the new response permission area and the resolution are determined based on the collision slot number, resolution, and base point BP1 of the response permission area (S13 → S14). Subsequently, the inquiry signal is transmitted and the response signal is received in the same procedure (S1 → S2 →...). When there are a plurality of collision slots, the above processing is performed for each collision slot. This process is as already described with reference to FIG.

  In this way, for the spatial slot corresponding to the time slot where a plurality of mobile stations exist, the response permission area is gradually narrowed and the resolution is increased until the signal collision is eliminated, and the response signal is decoded for all the mobile stations. Do.

  FIG. 9 is a flowchart showing the processing procedure of the mobile station. First, the carrier of the interrogation signal transmitted from the control station is detected (S21). If there is a carrier, the interrogation signal (question sentence) is decoded (S22 → S23), and the area corresponding to the response permission area in the interrogation signal (S24). That is, the latitude / longitude range is obtained based on the information of the response permission area, and it is determined whether or not the (latitude, longitude) of the local station obtained by the GPS receiver 23 exists within the range. If the own station exists in the response permission area, a response signal including the identification code of the own station is generated and transmitted (S25 → S26 → S27). If it does not exist, no response signal (response sentence) is created and transmitted.

  Through the processing of the control station and mobile station described above, the positions of mobile stations that are close to each other can be detected with high resolution, and conversely, the minimum required for mobile stations that are sufficiently separated from adjacent mobile stations. Since position information can be detected with a limited resolution, it is possible to effectively monitor a plurality of mobile stations with a small amount of data as a whole.

<< Second Embodiment >>
In the first embodiment, an example is shown in which the control station collects only the position information of the mobile station. However, in the second embodiment, desired information is obtained together with the position information.

  FIG. 10 is a diagram showing a format of a question signal (question sentence) and a response signal (response sentence) used in the mobile monitoring system according to the second embodiment. As shown in FIG. 10A, the question signal transmitted from the control station is composed of “synchronization signal”, “question index”, “response permission area”, “command”, and “error correction code”. Unlike the example shown in FIG. 3A, a “command” is provided. This “command” is a code representing the type of information (for example, the course and speed of the moving body) requested by the control station to report to the mobile station.

  As shown in FIG. 10B, the response signal transmitted by the mobile station is composed of “synchronization signal”, “response index”, “identification code”, “command answer”, and “error correction code”. Unlike the example shown in FIG. 3B, a “command answer” is provided. This “command answer” is information requested by the mobile station from the control station (in the above example, values such as the course and speed of the moving body).

  The mobile station monitoring process of the control station according to the second embodiment can also be expressed in the same manner as that shown in FIG. In the second embodiment, a response signal including a desired “command” is created in step S1 in FIG. Also, the mobile station processing can be expressed in the same manner as shown in FIG. In the second embodiment, information to answer the command included in the question signal is included in the response signal as “command answer” in step S26 of FIG.

<< Third Embodiment >>
In the first and second embodiments, it is assumed that there is a single control station, but a plurality of control stations may exist. If a combination of a certain interrogation signal and a response signal scheduled therewith is counted as one session, the system will not fail unless the time for performing the individual sessions overlaps. That is, a plurality of control stations can coexist.

  There are two methods for avoiding duplication of session execution time depending on the positional relationship between control stations. This third embodiment shows an example thereof.

  FIG. 11 is a diagram showing the relationship of the control station service areas in an area where two control stations exist. FIG. 11A shows a case where the control stations cannot receive each other's interrogation signals. In this case, the control stations α and β exist outside the service areas of each other, but when both service areas overlap, a line connecting the control stations α and β separately from the radio lines of the inquiry signal and the response signal So that each session can be recognized via this line. This avoids duplication of sessions to mobile stations γ existing in a common service area. That is, the control stations α and β determine the session execution time so that the session execution times do not overlap each other.

  FIG. 11B shows a case where the control stations α and β can receive the other party's interrogation signals. In this case, the other party's interrogation signal is directly received, each other's session is recognized, and duplication of a session with the mobile station δ existing outside the common service area and other sessions is avoided. That is, the control stations α and β determine the session execution time so that the session execution times do not overlap each other.

Needless to say, in addition to the examples shown in the above embodiments, the present invention can take various forms.
For example, in the example shown in FIG. 8, the mobile station that has been able to decode the response signal does not perform any further processing to increase the resolution, but first sets a response permission area with a coarse resolution within a predetermined monitoring area. Determine the approximate position of the mobile station by sending an interrogation signal, set the response permission area with high resolution in the area including the predetermined mobile station, as if focusing on each mobile station in the next stage, A process of transmitting a question signal is performed. Or, the operation for increasing the resolution is repeated. In this way, the position may be obtained with equal resolution (with position accuracy) for each mobile station by sequentially narrowing the response permission area without waste.

  Further, in the example shown above, when the response permission area is divided into a plurality of equally-spaced sections according to the two-dimensional coordinates, the corresponding sections are made to correspond to the time slots. The directions may be divided at equal intervals to assume a three-dimensional section, and each section may correspond to a time slot.

  Further, in the embodiment described above, the response scheduling is defined by using the elapsed time from the transmission / reception time of the interrogation signal or the value of a predetermined digit of the absolute time of the positioning system as the time slot number, but the interrogator 11 and the transponder 21 And response scheduling may be determined according to the elapsed time with reference to the common timing.

  Furthermore, in the example shown above, the ship is a moving body, but a mobile station is provided on a land vehicle, a system for monitoring the position of the vehicle, a mobile station is provided on an aircraft / aircraft, The present invention can be similarly applied to a system for monitoring the position and the motion state. Similarly, it can be applied to animals such as whales, bears, dogs, and even smaller animals.

It is a figure which shows the structure of the operation monitoring system shown by patent document 1. FIG. It is a block diagram which shows the structure of the mobile body monitoring system which is 1st Embodiment of this invention. It is a figure which shows the structure of the question signal and response signal which are used with the same mobile monitoring system. It is a figure which shows the relationship between a response permission area and a space slot. It is a figure which shows the timing relationship of a question signal and a response signal. It is a figure which shows operation which raises the resolution of a response permission area. It is a flowchart which shows the process sequence of a control station. It is a flowchart which shows the procedure of the mobile body monitoring process which a control station performs. It is a flowchart which shows the process sequence of a mobile station. It is a figure which shows the structure of the inquiry signal and response signal which are used with the mobile body monitoring system which concerns on 2nd Embodiment. It is a figure for demonstrating the method to prevent the duplication of the session in the mobile monitoring system which concerns on 3rd Embodiment.

Explanation of symbols

10-control station 20-mobile station α, β-control station γ, δ-mobile station

Claims (6)

Positioning means for obtaining position information of the own station, and a response permission area information for specifying a response permission area that is an area for permitting a response from the question signal and receiving a question signal transmitted from the control station. When the position of the local station extracted and obtained by the positioning means is within the response permission area, a response time slot is determined based on the position within the permission area, and a response signal is wirelessly transmitted to the time slot. Signal transmission means,
Question signal transmitting means for wirelessly transmitting an inquiry signal including the response permission area information to the control station, and the position of the mobile station according to the time slot that receives the response signal from the mobile station and receives the response signal And a mobile station position detecting means for obtaining a mobile body monitoring system. Positioning means for obtaining position information of the own station, and a response permission area information for specifying a response permission area that is an area for permitting a response from the question signal and receiving a question signal transmitted from the control station. When the position of the local station extracted and obtained by the positioning means is within the response permission area, a time slot is determined based on the position within the permission area, and a response is made after a time slot from the reception time of the question signal. Response signal transmitting means for wirelessly transmitting a signal,
A question signal transmitting means for wirelessly transmitting an inquiry signal including the response permission area information to the control station, and receiving the response signal from the mobile station, until receiving the response signal from a transmission time of the question signal A mobile station monitoring system comprising: mobile station position detecting means for determining a position of a mobile station corresponding to a time slot according to time.   The position in the response permission area corresponding to the time slot that received the response signal is designated as a new response permission area to increase the position resolution of the mobile station according to the time slot, and the question signal is transmitted again by the question signal transmitting means. The mobile monitoring system according to claim 1 or 2, wherein a response permission area setting means for transmitting is provided in the control station.   The position in the response permission area corresponding to the time slot where the response signal carrier could be detected and the response signal could not be decoded was designated as a new response permission area, and the position resolution of the mobile station corresponding to the time slot was determined. The mobile monitoring system according to claim 1 or 2, wherein response control area setting means for sending the question signal again by the question signal sending means is provided in the control station.   The time slot corresponds to a corresponding area when the response permission area is divided into a plurality of equally spaced areas according to two-dimensional coordinates or three-dimensional coordinates. The moving body monitoring system described in 1. The control station comprises means for including in the interrogation signal a command indicating the type of information requested to be reported to the mobile station,
The mobile monitoring system according to any one of claims 1 to 5, wherein the mobile station includes means for including command response information corresponding to the command in the response signal.

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