JP5366871B2 - Orientation detection device - Google Patents

Description

  The present invention relates to a configuration for detecting a direction in which an antenna that receives a signal is directed based on a signal from a global positioning system (GNSS) satellite.

  2. Description of the Related Art Conventionally, in an azimuth detecting device, a configuration for detecting the azimuth that a moving body is facing based on a signal from a GNSS satellite such as a GPS satellite is known. For example, Patent Document 1 discloses such an orientation detection device.

  Patent Document 1 discloses an azimuth detecting device configured as follows. In other words, the azimuth detection device disclosed in Patent Document 1 includes position information calculation means, absolute azimuth angle calculation means, directional antennas, relative azimuth angle detection means, and azimuth calculation means. The position information calculation means receives a GPS signal and calculates position information of the GPS satellite and position information of the moving body. The absolute azimuth calculating unit calculates an absolute azimuth angle of the GPS satellite in the moving body based on the position information of the GPS satellite and the position information of the moving body by the position information calculating unit. The directional antenna rotates in an azimuth direction with respect to a specific direction specified in the moving body. The relative azimuth angle detection means receives a radio wave from the GPS satellite by the directional antenna, and detects a relative azimuth angle of the GPS satellite in the moving body with respect to the specific direction based on the strength of the radio wave. The azimuth calculating means calculates an absolute azimuth angle in the specific direction in the moving body based on the relative azimuth angle and the absolute azimuth angle of the GPS satellite.

Japanese Patent Laid-Open No. 11-231038

  By the way, the structure which detects the direction of a moving body using the electronic compass which detects geomagnetism other than the structure which detects an azimuth | direction based on the signal from the GPS satellite mentioned above is conventionally known. However, due to the characteristics of the electronic compass, there is a possibility that the direction cannot be accurately detected in a place where the distortion of the magnetic field is severe.

  In this respect, since the azimuth detecting device disclosed in Patent Document 1 detects the azimuth in a specific direction based on the strength of radio waves received from GPS satellites, the azimuth can be detected without being affected by the magnetic field. . However, in the configuration of Patent Document 1, a change in the reception level from a specific satellite must be monitored for a certain period of time in order to examine the peak of the reception level. For this reason, when the direction of the moving body suddenly changes, it is difficult to immediately reflect the state of the moving body in the detection result. Further, the configuration of Patent Document 1 needs to include a driving device for rotating the GPS antenna itself or rotating a shielding member attached to the GPS antenna in order to monitor a change in reception level. . Accordingly, there is room for improvement from the viewpoint of simplifying the apparatus configuration.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to detect an orientation of an antenna accurately and quickly even in a stationary state without being affected by a magnetic field. Is to provide.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to the first aspect of the present invention, an azimuth detecting device configured as follows is provided. That is, the azimuth detection device includes a storage unit, an input unit, a processing unit, and an azimuth calculation unit. The storage unit stores in advance a function derived from the relationship between the reception angle of the signal of the antenna having directivity and the signal level. The input unit receives azimuth information and reception signal level of the GNSS satellite acquired based on a signal received by the antenna from the GNSS satellite. When the azimuth information and received signal level of a plurality of GNSS satellites are input to the input unit, the processing unit adapts the function to the relationship between the azimuth information and the received signal level obtained for each GNSS satellite. I do. The azimuth calculation unit calculates the orientation of the antenna based on a tendency of a calculated signal level calculated by a function adapted by the processing unit.

  Thereby, the process for detecting the direction of the antenna can be started when signals from a plurality of GNSS satellites can be received without having to continuously acquire signals from the GNSS satellites. Therefore, it is possible to detect the direction of the antenna almost in real time whether it is in a moving state or a stationary state. In addition, since the signal from the GNSS satellite is not affected by the magnetic field, the direction of the antenna can be accurately detected even in a place where the distortion of the magnetic field is severe in an environment where the signal from the GNSS satellite can be received. it can.

  The azimuth detecting device is preferably configured as follows. That is, the azimuth calculation unit calculates the direction of the antenna based on the azimuth information when the calculated signal level calculated by the function adapted by the processing unit is the highest or the azimuth information when the calculation signal level is the lowest.

  Thereby, the antenna direction can be calculated by a simple process of detecting the maximum value or the minimum value of the calculated signal level.

  In the azimuth detecting device, the function preferably includes a trigonometric function.

  Thereby, the change of the signal level according to the direction can be appropriately and easily expressed by a trigonometric function whose magnitude periodically changes in a cycle of 360 degrees. Further, since the signal level can be calculated by a relatively easy calculation process, it is possible to reduce the calculation cost necessary for calculating the azimuth.

  The azimuth detecting device is preferably configured as follows. That is, this azimuth detecting device includes an accuracy calculation unit. The accuracy calculation unit obtains the accuracy of the azimuth calculated by the azimuth calculation unit based on the difference between the calculated signal level and the received signal level.

  As a result, the received signal level actually received is compared with the calculated signal level, and thus the reliability of the calculation result by the azimuth calculating unit can be determined based on the accuracy.

  The azimuth detecting device is preferably configured as follows. That is, the accuracy calculation unit obtains the accuracy of the calculation result by the azimuth calculation unit by comparing the difference between the calculated signal level and the reception signal level in the same azimuth with a threshold value.

  As a result, even if the antenna cannot receive the signal from the GNSS satellite satisfactorily and the received signal level takes an extreme value, the calculation result may not be accurate by setting the threshold appropriately. Considerable processing can be performed.

  The azimuth detecting device is preferably configured as follows. That is, when the difference between the calculated signal level and the received signal level exceeds a threshold value, the received signal level exceeding the threshold value is excluded and the function is re-adapted to the processing unit.

  As a result, since the received signal level that deviates from the threshold is excluded, it is possible to realize a configuration in which the azimuth can be accurately calculated even in a place where the reception environment is bad.

  According to a second aspect of the present invention, an azimuth detecting device configured as follows is provided. That is, the azimuth detection device includes a storage unit, an input unit, an acquisition unit, a processing unit, and an azimuth calculation unit. The storage unit stores in advance a function derived from the relationship between the signal reception level and the signal level of the antenna set in which a plurality of directional antennas are arranged according to a predetermined arrangement relationship. The input unit receives GNSS satellite azimuth information viewed from a reference position acquired based on a signal received by the antenna from a GNSS satellite, and a received signal level of a signal received by each antenna. Is done. The acquisition unit acquires a signal level for adaptation according to the azimuth of the GNSS satellite based on the received signal level of the signal received for each antenna from the same GNSS satellite. When the azimuth information and the received signal level of a plurality of GNSS satellites are input to the input unit for each antenna, the processing unit has a relationship between the azimuth information obtained for each GNSS satellite and the adaptation signal level. The process which adapts the said function to is performed. The azimuth calculation unit calculates the orientation of the antenna set based on the tendency of the calculated signal level calculated by the function adapted by the processing unit.

  Thereby, the process for detecting the direction of the antenna set can be started when signals from a plurality of GNSS satellites can be received without having to continuously acquire signals from the GNSS satellites. Therefore, the orientation of the antenna set can be detected almost in real time regardless of whether it is in a moving state or a stationary state. In addition, since the signal from the GNSS satellite is not affected by the magnetic field, the direction of the antenna set can be accurately detected even in a place where the distortion of the magnetic field is severe as long as the signal can be received from the GNSS satellite. Can do. In addition, since the adaptation signal level is acquired based on the signals received by each of the plurality of antennas, the azimuth can be accurately calculated.

  The azimuth detecting device is preferably configured as follows. That is, the azimuth calculating unit calculates the direction of the antenna set based on the azimuth information when the calculated signal level calculated by the function adapted by the processing unit is the highest or the azimuth information when the level is the lowest.

  Thereby, the orientation of the antenna set can be calculated by a simple process of detecting the maximum value or the minimum value of the calculated signal level.

  In the azimuth detecting device, the function preferably includes a trigonometric function.

  Thereby, the change of the signal level according to the direction can be appropriately and easily expressed by a trigonometric function whose magnitude periodically changes in a cycle of 360 degrees. Further, since the signal level can be calculated by a relatively easy calculation process, it is possible to reduce the calculation cost necessary for calculating the azimuth.

  The azimuth detecting device preferably includes an accuracy calculation unit. The accuracy calculation unit obtains the accuracy of the azimuth calculated by the azimuth calculation unit based on a difference between the calculated signal level and the adaptation signal level.

  As a result, the matching signal level based on the actually received signal level is compared with the calculated signal level, so that the reliability of the calculation result by the azimuth calculating unit can be determined based on the accuracy.

  The azimuth detecting device is preferably configured as follows. That is, the accuracy calculation unit obtains the accuracy of the calculation result by the azimuth calculation unit by comparing the difference between the calculated signal level and the adaptation signal level in the same azimuth with a threshold value.

  As a result, even if the antenna cannot receive the signal from the GNSS satellite satisfactorily and the adaptation signal level takes an extreme value, the calculation result may not be accurate by setting the threshold appropriately. Considerable processing can be performed.

  The azimuth detecting device is preferably configured as follows. That is, when the difference between the calculated signal level and the adaptation signal level exceeds a threshold, the adaptation signal level exceeding the threshold is excluded and the function is re-adapted to the processing unit.

  As a result, since the signal level for adaptation that deviates from the threshold value is excluded, it is possible to realize a configuration in which the azimuth can be accurately calculated even in a place where the reception environment is bad.

  The azimuth detecting device is preferably configured as follows. That is, the plurality of antennas are configured by a first antenna and a second antenna having directivities in opposite directions. The acquisition unit acquires a matching signal level by taking a difference between a reception signal level received by the first antenna and a reception signal level received by the second antenna.

  As a result, it is possible to acquire a conforming signal level in which the error is canceled by a simple process of obtaining the difference. In addition, since the difference between signal levels having directivities in opposite directions is taken, the variation range of the signal level for adaptation can be increased, and the reliability of the direction calculated by the direction calculation unit can be effectively improved. Can do.

  According to a third aspect of the present invention, in a direction detection method for calculating the direction of an antenna having directivity, a method including the following four steps is provided. That is, in the first step, a function derived from the relationship between the reception angle of the antenna signal and the signal level is derived. In the second step, the azimuth information and received signal level of the GNSS satellite acquired by the antenna based on the signal received from the GNSS satellite are input. In the third step, when the azimuth information and the reception signal level of a plurality of GNSS satellites are input, the function is adapted to the relationship between the azimuth information and the reception signal level obtained for each GNSS satellite. In the fourth step, the direction of the antenna is calculated based on the tendency of the calculated signal level calculated based on the function.

  Thereby, the process for detecting the direction of the antenna can be started when signals from a plurality of GNSS satellites can be received without having to continuously acquire signal levels from the GNSS satellites. Therefore, it is possible to detect the direction of the antenna almost in real time whether it is in a moving state or a stationary state. In addition, since the signal from the GNSS satellite is not affected by the magnetic field, the direction of the antenna can be accurately detected even in a place where the distortion of the magnetic field is severe in an environment where the signal from the GNSS satellite can be received. it can.

  According to a fourth aspect of the present invention, in an orientation detection method for calculating the orientation of an antenna set in which a plurality of antennas having directivity are arranged according to a predetermined arrangement relationship, a method including the following five steps: Provided. That is, in the first step, a function derived from the relationship between the reception angle of the signal of the antenna set and the signal level is derived. In the second step, the GNSS satellite azimuth information viewed from a reference position acquired based on the signal received by the antenna from the GNSS satellite and the received signal level of the signal received by each antenna are input. Is done. In the third step, a matching signal level corresponding to the azimuth of the GNSS satellite is acquired based on the received signal level of the signal received for each antenna from the same GNSS satellite. In the fourth step, when the azimuth information and the received signal level of a plurality of GNSS satellites are input for each antenna, the function is calculated based on the relationship between the azimuth information obtained for each GNSS satellite and the adaptation signal level. Is fit. In the fifth step, the orientation of the antenna set is calculated based on the tendency of the calculated signal level calculated by the adapted function.

  Thereby, the process for detecting the direction of the antenna set can be started when signals from a plurality of GNSS satellites can be received without having to continuously acquire signals from the GNSS satellites. Therefore, the orientation of the antenna set can be detected almost in real time regardless of whether it is in a moving state or a stationary state. In addition, since the signal from the GNSS satellite is not affected by the magnetic field, the direction of the antenna set can be accurately detected even in a place where the distortion of the magnetic field is severe as long as the signal can be received from the GNSS satellite. Can do. In addition, since the adaptation signal level is acquired based on the signals received by each of the plurality of antennas, the azimuth can be accurately calculated.

The conceptual diagram which showed the whole structure of the azimuth | direction detection apparatus of 1st Embodiment. The functional block diagram of the analyzer of 1st Embodiment. The graph which showed the relationship between a signal level and an azimuth for every GPS satellite. The conceptual diagram which showed the whole structure of the azimuth | direction detection apparatus of 2nd Embodiment. The functional block diagram of the analyzer of 2nd Embodiment. The graph which showed the relationship between a signal level and an azimuth for every GPS satellite. The graph which shows the difference data which took the difference of the data which the 2nd GPS antenna received from the data which the 1st GPS antenna received. The graph which showed an example of the relationship between a signal level and an azimuth for every GPS satellite in order to demonstrate the relationship between a fitting result and a threshold value. The schematic diagram explaining the experiment to which the azimuth | direction detection method of this invention is applied. The graph which showed the detection result of the experiment which applied the direction detection method of this invention.

  Next, an embodiment of the invention will be described. FIG. 1 is a conceptual diagram showing an overall configuration of the azimuth detecting device 10 according to the first embodiment. The azimuth detecting device 10 according to the present embodiment is configured to detect the azimuth in the direction of the GPS antenna 11 using a GNSS (Global Navigation Satellite System). In the present embodiment, GPS (Global Positioning System) is used as GNSS.

  As shown in FIG. 1, the azimuth detection device 10 according to the first embodiment includes a GPS antenna 11, a shielding plate 12, a GPS receiver 13, and an analysis device 14.

  The GPS antenna 11 is for receiving a signal from the GPS satellite 1, and a flat patch antenna is employed. As shown in FIG. 1, there are a plurality of GPS satellites 1 around the earth, and the GPS antenna 11 receives signals from these GPS satellites 1.

  As shown in FIG. 1, the GPS antenna 11 is attached to a flat portion of a shielding plate 12 made of an appropriate metal. In the following description, the surface in contact with the shielding plate 12 is the back side of the GPS antenna 11, and the surface opposite to the back side is the front side of the GPS antenna 11. In the azimuth detecting device 10 of the present embodiment, the front direction of the GPS antenna 11 (the direction indicated by the arrow in FIG. 1) is determined as the reference direction (predetermined direction) for detecting the azimuth.

  Since the shielding plate 12 functions to attenuate the signal from the GPS satellite 1, the GPS antenna 11 has poor reception sensitivity with respect to the signal from the back side. On the other hand, since there is no shielding plate 12 on the front side of the GPS antenna 11, signals from the front side can be received with higher sensitivity than on the back side. Thus, the GPS antenna 11 of the present embodiment is configured as a directional antenna that receives signals from the front with high sensitivity.

  Based on the positioning signal received through the GPS antenna 11, the GPS receiver 13 acquires the position of each GPS satellite 1 that has transmitted the positioning signal and the signal level at the time of reception. The positioning signal includes almanac data that is orbit information of all satellites, and ephemeris data that is detailed orbit information of the GPS satellite 1 that has transmitted the signal. The GPS receiver 13 confirms a GPS satellite 1 that can receive a positioning signal based on the almanac data, and acquires an accurate position of each GPS satellite 1 based on the ephemeris data.

  The GPS receiver 13 acquires the current position of the GPS antenna 11 based on positioning signals (positions of the respective GPS satellites 1) from a plurality (at least three) of the GPS satellites 1. The GPS receiver 13 of the present embodiment acquires the azimuth angle of the GPS satellite 1 viewed from the GPS antenna 11 for each GPS satellite 1 based on the current position of the GPS antenna 11 and the position of the GPS satellite 1. The azimuth angle of the GPS satellite 1 obtained in this way is output to the analysis device 14. The GPS receiver 13 also outputs the signal level when receiving a signal from the GPS satellite 1 to the analysis device 14 for each GPS satellite 1.

  The analysis device 14 analyzes the data received from the GPS receiver 13 and performs detection processing for detecting the direction (direction in the front direction) that the GPS antenna 11 is facing. Next, a detailed configuration of the analysis device 14 will be described with reference to FIGS. 2 and 3. FIG. 2 is a functional block diagram of the analysis device 14 according to the first embodiment. FIG. 3 is a graph showing the relationship between the signal level and the azimuth for each GPS satellite 1.

  In addition, the number following SV (Satellite Vehicle) in the graph of FIG. 3 means a satellite number. Azimuth (deg) shown on the horizontal axis is the azimuth of the GPS satellite 1 viewed from the position of the GPS antenna 11. Further, C / NO (dB-Hz) shown on the vertical axis indicates the ratio of carrier wave to noise, and indicates the strength of the signal level at the time of reception. The larger the value of C / NO, the more the GPS antenna 11 is receiving a signal from the GPS satellite 1 in a better state.

  The analysis device 14 of this embodiment is configured using a general-purpose personal computer. The analysis device 14 includes a CPU as a calculation unit and a control unit, and a ROM, a RAM, and a hard disk as storage units. On the hard disk, a program or the like for detecting the direction in which the GPS antenna 11 is directed based on the strength of the signal level of the GPS satellites 1 having different azimuth angles is installed using an appropriate storage medium.

  As shown in FIG. 2, the analysis device 14 includes a satellite data input unit 51, a fitting processing unit 52, a fitting function storage unit 53, and an azimuth calculation unit 55 through the cooperation of the hardware and software. And the result output unit 57 is constructed.

  The satellite data input unit 51 acquires the azimuth angle of each GPS satellite 1 and the signal level at the time of reception from the GPS receiver 13. The satellite data input unit 51 acquires a plurality of signal level data of the GPS satellites 1 existing at positions where signals can be received, and outputs a group of these signal level data (signal level data) to the fitting processing unit 52. . This signal level data is data indicating a tendency of a signal level that varies depending on the direction (direction at that time) of the GPS antenna 11. An example of this signal level data is shown in the graph of FIG.

  The fitting processing unit 52 calls a fitting function stored in advance in the fitting function storage unit 53, and fits (fits) the fitting function to the signal level data (see FIG. 3). The fitting processing unit 52 outputs the result of fitting the fitting function to the azimuth calculating unit 55.

  Here, the fitting function stored in the fitting function storage unit 53 will be described. That is, a plurality of GPS satellites 1 revolve around the earth, and even if the time or the position of the GPS antenna 11 on the earth changes, some GPS satellites 1 out of the plurality of GPS satellites 1 It exists in the various directions seen from the antenna 11. In addition, the GPS antenna 11 of the present embodiment is configured to have directivity, and receives a signal in the direction (front direction) in which the GPS antenna 11 is facing most strongly. Therefore, when the GPS antenna 11 receives signals from a plurality of GPS satellites 1 present in various directions at the same time, the signal from the GPS satellites 1 present on the front side tends to be received strongly and exists on the back side. The signal from the GPS satellite 1 tends to be received weakly. A fitting function represents such a tendency of the signal level that changes depending on the angle with respect to the direction of the antenna as a function.

ただし、
Ａ：ＧＰＳアンテナ１１から見た各ＧＰＳ衛星１の方位角
φ：ＧＰＳアンテナ１１の正面方向の方位角
ａ，ｂ：フィッティング定数 In the present embodiment, the fitting function is expressed as in Expression (1).

However,
A: Azimuth angle of each GPS satellite 1 viewed from the GPS antenna 11 φ: Azimuth angle a, b in the front direction of the GPS antenna 11 Fitting constant

  The fitting constants a and b are obtained in advance by performing the following preliminary measurement. That is, first, the GPS antenna 11 is fixed in a predetermined direction in an appropriate place where the reception environment is good. For example, when the GPS antenna 11 is installed facing true north, the value of φ is fixed at 0 degrees. Then, the relationship between the azimuth angle of the GPS satellite 1 and the signal level is measured over a predetermined time to obtain experimental data. The fitting constant (parameter) is determined by applying the above equation (1) so as to match the experimental data obtained in the preliminary measurement.

  As described above, the tendency of the change in the signal level according to the angle of the GPS antenna 11 with respect to the predetermined direction can be expressed as a function. The fitting function in which the fitting constant is set by this preliminary measurement is stored in advance in the fitting function storage unit 53 by an appropriate method. The method for determining the fitting constant described above is merely an example, and it is needless to say that the parameters can be determined by a method different from this method.

  The azimuth calculating unit 55 is for calculating the azimuth in the front direction of the GPS antenna 11 based on the fitting result. The azimuth calculation unit 55 of the present embodiment is configured so that the azimuth can be detected in four directions of east, west, south, and north. More specifically, when true north is 0 degree and the angle is set so that the clockwise direction when viewed from above is positive, 45 degrees to 135 degrees (east range), 135 degrees to 225 degrees (South range) The direction is divided into four ranges of 225 degrees to 315 degrees (west range) and 315 degrees to 45 degrees (north range) at intervals of 90 degrees. Then, the azimuth is determined based on the section to which the azimuth belongs when the peak (maximum value or minimum value) of the signal level (calculated signal level) calculated by the fitting function applied to the fitting processing unit 52 occurs. In the configuration of the present embodiment, the GPS antenna 11 is configured so as to receive the front-side signal most strongly. Therefore, it is possible to determine the azimuth when the maximum signal level is taken as the front direction of the GPS antenna 11. Further, the direction of the back surface of the GPS antenna 11 can be determined based on the direction when the minimum value of the signal level is taken. When the fitting result as shown in FIG. 3 is input, the azimuth calculation unit 55 determines that the azimuth of the negative peak (minimum value) of the signal level is in the range of 135 degrees to 225 degrees. It is determined that it is facing the opposite direction, that is, north. The azimuth calculation unit 55 outputs the determination result (calculation result) determined in this way to the result output unit 57.

  The result output unit 57 displays the determination result input from the direction calculation unit 55 on the display (display unit) of the personal computer. Thereby, the user can grasp | ascertain which direction of the GPS antenna 11 has faced east, west, south, and north.

  As described above, the azimuth detecting device 10 of the first embodiment is configured as follows. That is, the direction detection device 10 includes a fitting function storage unit 53, a satellite data input unit 51, a fitting processing unit 52, and an direction calculation unit 55. The fitting function storage unit 53 stores in advance a fitting function derived from the correlation between the reception angle of the signal of the GPS antenna 11 having directivity and the signal level. In the satellite data input unit 51, the direction information indicating the direction of the GPS satellite 1 viewed from the GPS antenna 11 obtained from the GPS antenna 11 based on the signal received from the GPS satellite 1, and the signal level of the received signal ( Received signal level). When the azimuth information and signal levels of a plurality of GPS satellites 1 are input to the satellite data input unit 51, the fitting processing unit 52 determines the fitting function based on the relationship between the azimuth and the received signal level obtained for each GPS satellite 1. Process that fits. The direction calculation unit 55 calculates the direction of the GPS antenna 11 based on the tendency of the signal level (calculated signal level) calculated by the fitting function adapted by the fitting processing unit 52.

  Thereby, the process for detecting the direction of the GPS antenna 11 in a predetermined direction can be started when signals from the plurality of GPS satellites 1 can be received without having to continuously acquire signals from the GPS satellites 1. . Therefore, the direction of the GPS antenna 11 can be detected almost in real time regardless of whether it is in a moving state or a stationary state. In addition, since the signal from the GPS satellite 1 is not affected by the magnetic field, the direction of the GPS antenna 11 can be accurately set even in a place where the distortion of the magnetic field is severe in an environment where the signal from the GPS satellite 1 can be received. Can be detected.

  In the azimuth detecting device 10 of the present embodiment, the direction of the antenna is determined based on the azimuth information when the signal level calculated by the fitting function adapted by the fitting processing unit 52 is the highest or the azimuth information when the signal level is the lowest. calculate.

  Thereby, the direction of the antenna can be calculated by a simple process of detecting the maximum value or the minimum value of the signal level calculated by the fitting function.

  In the azimuth detecting device 10 of the present embodiment, the function is set to include a cosine function.

  Thereby, the change of the signal level according to the direction can be appropriately and easily expressed by the cosine function whose magnitude periodically changes in a cycle of 360 degrees. Further, since the signal level can be calculated by a relatively easy calculation process, it is possible to reduce the calculation cost necessary for calculating the azimuth.

  Next, the direction detection device 30 of the second embodiment will be described. The azimuth detecting device 30 according to the second embodiment detects a azimuth in a predetermined direction set based on an arrangement relationship of an antenna set including a plurality of GPS antennas based on signals received by the plurality of GPS antennas. It is configured. FIG. 4 is a conceptual diagram showing the overall configuration of the azimuth detecting device 30 of the second embodiment. In the following description, the same or similar configurations as those of the azimuth detecting device 10 described in the first embodiment may be denoted by the same reference numerals in the drawings, and description thereof may be omitted.

  As shown in FIG. 4, the azimuth detecting device 30 of the second embodiment includes a first GPS antenna 21, a second GPS antenna 31, a shielding plate 12, a first GPS receiver 23, a second GPS receiver 33, and an analysis. And a device 14.

  Each of the first GPS antenna 21 and the second GPS antenna 31 is for receiving a signal from the GPS satellite 1, and is configured as a flat patch antenna. As shown in FIG. 4, the 1st GPS antenna 21 is attached to the plane part of the shielding board 12 similarly to 1st Embodiment. On the other hand, the second GPS antenna 31 is attached to the opposite side of the shielding plate 12 to which the first GPS antenna 21 is attached, and is disposed on the back side of the first GPS antenna 21 with the shielding plate 12 interposed therebetween.

  The first GPS antenna 21 and the second GPS antenna 31 are arranged so as to face each other with the shielding plate 12 interposed therebetween, and thus have directivity in opposite directions. That is, the first GPS antenna 21 has a high sensitivity for receiving a signal from the front side and a low sensitivity for receiving a signal from the back side. On the other hand, the second GPS antenna 31 has low sensitivity to receive signals from the front side of the first GPS antenna 21 (the back side of the second GPS antenna 31), and the back side of the first GPS antenna 21 (the front side of the second GPS antenna 31). The sensitivity to receive signals from is high.

  In the azimuth detecting device 30 of the present embodiment, the predetermined direction of the antenna set composed of the first GPS antenna 21 and the second GPS antenna 31 is set to the front direction of the first GPS antenna 21. In the following description, when the direction detection device 30 detects the direction, it means that the direction of the front direction of the first GPS antenna 21 is detected.

  A signal received by the first GPS antenna 21 is input to the first GPS receiver 23. The first GPS receiver 23 outputs data indicating the direction of each GPS satellite 1 acquired based on this signal and data indicating the signal level to the analysis device 14. A signal received by the second GPS antenna 31 is input to the second GPS receiver 33. Data indicating the direction of each GPS satellite 1 acquired based on the signal received by the second GPS antenna 31 and a signal level are indicated. The data is output to the analysis device 14.

  The analysis device 14 according to the second embodiment analyzes the data input from the first GPS receiver 23 and the data input from the second GPS receiver 33, and determines the front direction azimuth (antenna set) of the first GPS antenna 21. Direction). Next, a detailed configuration of the analysis device 14 will be described with reference to FIGS. 5, 6, and 7. FIG. 5 is a functional block diagram of the analysis device 14 of the second embodiment. FIG. 6 is a graph showing the relationship between the signal level and the azimuth for each GPS satellite 1. FIG. 7 is a graph showing difference data obtained by taking a difference between data received by the second GPS antenna 31 from data received by the first GPS antenna 21.

  As shown in FIG. 5, the analysis device 14 includes a satellite data input unit 51, a difference data acquisition unit 56, a fitting processing unit 52, a fitting function storage unit 53, an accuracy calculation unit 54, and an azimuth calculation unit 55. And the result output unit 57 is constructed.

  The satellite data input unit 51 outputs the signal level data obtained for each GPS satellite 1 to the differential data acquisition unit 56 as the signal level when the first GPS antenna 21 receives the signal. This signal level data is data indicating a tendency of a signal level that varies depending on the direction (direction at that time) of the first GPS antenna 21. An example of signal level data acquired based on the signal received by the first GPS antenna 21 is shown in the graph of FIG.

  Further, the satellite data input unit 51 outputs the signal level data obtained for each GPS satellite 1 to the difference data acquisition unit 56 as the signal level when the second GPS antenna 31 receives the signal. This signal level data is data indicating a tendency of a signal level that varies depending on the direction (direction at that time) of the second GPS antenna 31. An example of signal level data acquired based on the signal received by the second GPS antenna 31 is shown in the graph of FIG.

  The difference data acquisition unit 56 acquires the signal level acquired based on the signal received by the first GPS antenna 21 from the GPS satellite 1 and the signal level acquired based on the signal received by the second GPS antenna 31 from the same GPS satellite 1. Is obtained as the signal level for adaptation. The difference data acquisition unit 56 acquires the signal level for adaptation for each GPS satellite 1. The difference data acquisition unit 56 outputs the adaptation signal level acquired for each GPS satellite 1 to the fitting processing unit 52 as adaptation signal level data. FIG. 7 is a graph showing an example of the adaptation signal level data acquired by the difference data acquisition unit 56.

ただし、
Ａ：第１ＧＰＳアンテナ２１（アンテナ組）から見た各ＧＰＳ衛星１の方位角
φ：アンテナ組の所定方向（第１ＧＰＳアンテナ２１の正面方向）の方位角
ａ，ｂ：フィッティング定数 The fitting processing unit 52 fits the fitting function called from the fitting function storage unit 53 to the fitting signal level data (see FIG. 7), and outputs the result to the accuracy calculating unit 54. The fitting function is a function derived so as to conform to the conforming signal level, and is expressed as in Expression (2). Expression (2) can be derived based on Expression (1) described in the first embodiment.

However,
A: Azimuth angle φ of each GPS satellite 1 viewed from the first GPS antenna 21 (antenna set): Azimuth angle a, b in a predetermined direction (front direction of the first GPS antenna 21) of the antenna set: fitting constant

  As shown in the equation (2), the fitting constant b can be eliminated by taking the difference, and the arithmetic processing can be simplified. Note that the fitting constant a is obtained by preliminary measurement as in the first embodiment. For example, the preliminary measurement described in the first embodiment is performed by each of the first GPS antenna 21 and the second GPS antenna 31. Next, as in the description of the difference data acquisition unit 56, difference data (conformance signal level data) of the measurement results obtained for each of the first GPS antenna 21 and the second GPS antenna 31 is acquired. Then, the fitting function shown in Equation (2) is fitted to the difference data, and a fitting constant is determined based on the result.

  The accuracy calculation unit 54 is for determining the reliability of the calculation result output from the fitting processing unit 52. The accuracy calculation unit 54 of the present embodiment compares the signal level calculated by the fitting function with the adaptation signal level based on a preset threshold, and if the adaptation signal level exceeds the threshold, It is determined that the reliability of the calculation result is low. When it is determined that the reliability of the calculation result is low, the accuracy calculation unit 54 of the present embodiment excludes the data of the matching signal level that exceeds the threshold value, and causes the fitting processing unit 52 to perform the fitting process again.

  By the way, the signal level received by the GPS antenna may vary greatly depending on the surrounding environment. For example, when there is a tall structure such as a building around the GPS antenna, the position of the GPS satellite 1 viewed from the GPS antenna may be just behind the structure and become a blind spot. In this state, the signal from the GPS antenna cannot be received at all, or even if it can be received, the signal level is significantly lowered, and the value of the conforming signal level may take an extreme value. Considering this point, the azimuth detecting device 30 according to the second embodiment is configured to determine whether the reliability of the azimuth calculated by the accuracy calculation unit 54 is high or low.

  FIG. 8 is a graph showing an example of the relationship between the signal level and the azimuth for each GPS satellite 1 in order to explain the relationship between the fitting result and the threshold value. In the example shown in FIG. 8, the difference between the adaptation signal level of the GPS satellite 1 having an azimuth angle of 45 degrees and the signal level calculated by the fitting function exceeds a preset threshold value. In this case, the accuracy calculation unit 54 performs a process of excluding the value of the adaptation signal level exceeding the threshold, and performs the fitting process again based on the adaptation signal level data excluding the adaptation signal level exceeding the threshold. Make it.

  The fitting processing unit 52 fits the fitting function to the fitting signal level data from which the fitting signal level exceeding the threshold is excluded, and outputs the result to the accuracy calculating unit 54 again. The accuracy calculation unit 54 determines for each GPS satellite 1 whether or not the adaptation signal level exceeds the threshold value. If it is determined that there is no adaptation signal level exceeding the threshold in the input adaptation signal level data, the fitting result is output to the bearing calculation unit 55. The setting of the threshold value can be changed by the user by operating the operation means (mouse, keyboard, etc.) of the analysis device 14.

  The azimuth calculation unit 55 of the second embodiment is configured to detect eight azimuths of north, northeast, east, southeast, south, southwest, west, and northwest. More specifically, the azimuth calculation unit 55 divides the azimuth at intervals of 45 degrees, and calculates the direction depending on which division the peak azimuth of the fitting function obtained from the fitting result corresponds to. For example, 22.5 to 67.5 degrees (northeast range), 67.5 to 112.5 degrees (east range), 112.5 to 157.5 degrees (southeast range), 157.5 The direction is divided into eight ranges such as 202.5 degrees (south range). Based on the division set in this way and the azimuth at the peak of the signal level calculated by the function, the azimuth of the antenna set in a predetermined direction (front direction of the first GPS antenna 21) is determined. In the case of the fitting result as shown in FIG. 7, since the azimuth when the signal level calculated in the fitting function takes the maximum value is in the range of 157.5 degrees to 202.5, the first GPS antenna 21 is facing. The direction is determined to be south. In this way, the determination result (calculation result) determined by the azimuth calculation unit 55 is output to the result output unit 57, and the result output unit 57 displays the determination result on the display.

  Next, with reference to FIG. 9 and FIG. 10, the result of the experiment performed using the direction detection method of the present invention will be described. FIG. 9 is a schematic diagram for explaining an experiment to which the direction detection method of the present invention is applied. FIG. 10A is a graph showing the result of an experiment in which azimuth is detected based on a signal received by one GPS antenna, as described in the first embodiment. FIG. 10B is a graph showing the results of experiments in which azimuth detection was performed based on signals received by two GPS antennas, as described in the second embodiment. In FIG. 10, the horizontal axis indicates the elapsed time from the start of the experiment. The vertical axis represents the direction of the detection direction calculated by the analysis device 14. Further, the graphs shown in FIG. 10A and FIG. 10B are not obtained by one measurement, but are obtained by plotting the experiment results by performing a plurality of experiments.

  As shown in FIG. 9, in this experiment, the first GPS antenna 21 and the second GPS antenna 31 are attached to a rotating body 60 that is configured to be switchable in units of 90 degrees in plan view so that it can face east, west, north, and south. It was done. The rotating body 60 functions as a shielding member, and as described in the second embodiment, the first GPS antenna 21 and the second GPS antenna 31 are attached to the rotating body 60 so as to have directivity in opposite directions. It has been. The detection direction (predetermined direction) is set in a direction orthogonal to a virtual line connecting the first GPS antenna 21 and the second GPS antenna 31.

  As shown in FIG. 9, the detection direction is west at the start of the experiment. The first GPS antenna 21 faces north, and the second GPS antenna 31 faces south. That is, the detection direction is west (the first GPS antenna 21 is north) from the start 0 second to 60 seconds. When 60 seconds have elapsed from the start, the rotating body 60 rotates so that the detection direction faces south. Then, after 120 seconds have elapsed from the start, the rotating body 60 rotates so that the detection direction faces east. Similarly, every time 60 seconds elapse, the detection direction is rotated 90 degrees and this operation is repeated until the detection direction turns to the west again.

  FIG. 10 (a) shows the result of calculating the azimuth by equation (1) based on the signal level of the signal received by the first GPS antenna 21 and the equation (1) based on the signal level of the signal received by the second GPS antenna 31. The results of calculating the azimuth according to 1) are shown. On the other hand, in FIG. 10B, Expression (2) is applied to the adaptation signal level obtained by taking the difference between the signal level received by the first GPS antenna 21 and the signal level received by the second GPS antenna 31. The results of calculating the azimuth using it are shown.

  Comparing FIG. 10 (a) and FIG. 10 (b), the azimuth was detected based on the signal level received by two GPS antennas, compared to the case where the azimuth was calculated based on the signal level received by one GPS antenna. It can be seen that the detection accuracy is higher in the case. This is because the difference between the signal levels of the first GPS antenna 21 and the second GPS antenna 31 whose directivities are opposite to each other is taken so that the errors cancel each other, or the signal level It is conceivable that the change width of the peak is increased and the accuracy of peak detection by the azimuth calculation unit 55 is improved.

  As described above, the azimuth detecting device 30 of the second embodiment is configured as follows. That is, the azimuth detection device 30 includes a fitting function storage unit 53, a satellite data input unit 51, a difference data acquisition unit 56, a fitting processing unit 52, and an azimuth calculation unit 55. The fitting function storage unit 53 stores in advance a fitting function derived from the correlation between the reception angle of the signal of the antenna set in which a plurality of directional GPS antennas are arranged according to a predetermined arrangement relationship and the signal level. The satellite data input unit 51 receives azimuth information indicating the azimuth of the GPS satellite 1 viewed from a reference position acquired based on a signal received by the first GPS antenna 21 or the second GPS antenna 31 from the GPS satellite 1. In addition, the satellite data input unit 51 receives a signal level (reception signal level) of a signal received by each of the first GPS antenna 21 and the second GPS antenna 31. The difference data acquisition unit 56 acquires the signal level for adaptation according to the direction of the GPS satellite 1 based on the signal level of the signal received by the first GPS antenna 21 and the second GPS antenna 31 from the same GPS satellite 1. When the azimuth information and signal level of a plurality of GPS satellites 1 are input to the satellite data input unit 51 for each GPS antenna, the fitting processing unit 52 obtains the azimuth information and the matching signal level obtained for each GPS satellite 1. Process that fits the function in relation to. The azimuth calculation unit 55 then determines a predetermined direction of the first GPS antenna 21 and the second GPS antenna 31 (antenna set) based on the tendency of the signal level (calculated signal level) calculated by the fitting function adapted by the fitting processing unit 52. Calculate the direction that is facing.

  Thereby, the process for detecting the direction of the antenna set can be started when signals from a plurality of GPS satellites 1 can be received without having to continuously acquire signal levels from the GPS satellites 1. Therefore, the orientation of the antenna set can be detected almost in real time regardless of whether it is in a moving state or a stationary state. In addition, since the signal from the GPS satellite 1 is not affected by the magnetic field, the antenna set in a predetermined direction (first GPS) can be used even in a place where the distortion of the magnetic field is severe as long as the signal from the GPS satellite 1 can be received. The front direction of the antenna 21) can be accurately detected. In addition, since the adaptation signal level is acquired based on the signals received by the first GPS antenna 21 and the second GPS antenna 31, the azimuth can be accurately calculated.

  Further, the azimuth detecting device 30 of the present embodiment is configured as follows. That is, the azimuth calculation unit 55 determines the direction of the antenna set in a predetermined direction based on the azimuth information when the calculated signal level calculated by the fitting function fitted by the fitting processing unit 52 is the highest or the azimuth information when the signal level is the lowest. calculate.

  Thereby, the orientation of the antenna set can be calculated by a simple process of detecting the maximum value or the minimum value of the calculated signal level.

  In the azimuth detecting device 30 of this embodiment, the function is set so as to include a cosine function.

  Thereby, the change of the signal level according to the direction can be appropriately and easily expressed by the cosine function whose magnitude periodically changes in a cycle of 360 degrees. Further, since the signal level can be calculated by a relatively easy calculation process, it is possible to reduce the calculation cost necessary for calculating the azimuth.

  Further, the azimuth detection device 30 of the present embodiment includes an accuracy calculation unit 54. The accuracy calculation unit 54 calculates the direction calculated by the direction calculation unit 55 based on the difference between the adaptation signal level acquired by the difference data acquisition unit 56 and the signal level calculated by the function applied by the fitting processing unit 52. Is determined in advance.

  As a result, since the adaptation signal level based on the actually received signal level is compared with the calculated signal level, the reliability of the calculation result calculated by the bearing calculation unit based on the accuracy is determined in advance. Can do.

  Further, the azimuth detecting device 30 of the present embodiment is configured as follows. That is, the accuracy calculation unit 54 obtains the accuracy of the calculation result by the azimuth calculation unit 55 in advance by comparing the difference between the calculated signal level and the matching signal level in the same azimuth with a preset threshold value.

  As a result, even if the GPS antenna cannot receive the signal from the GPS satellite 1 satisfactorily and the adaptation signal level takes an extreme value, the calculation result may not be accurate by setting the threshold appropriately. It is possible to perform processing in consideration of the characteristics.

  Further, the azimuth detecting device 30 of the present embodiment is configured as follows. That is, when the difference between the calculated signal level and the adaptation signal level exceeds the threshold value, the fitting signal level exceeding the threshold value is excluded and the fitting processing unit 52 is adapted again.

  As a result, since the signal level for adaptation that deviates from the threshold value is excluded, it is possible to realize a configuration in which the azimuth can be accurately calculated even in a place where the reception environment is bad.

  Further, the azimuth detecting device 30 of the present embodiment is configured as follows. That is, as a plurality of GPS antennas, a first antenna and a second antenna having directivity in opposite directions are provided. The difference data obtaining unit 56 obtains a matching signal level by taking the difference between the signal level received by the first GPS antenna 21 and the signal level received by the second GPS antenna 31.

  As a result, it is possible to acquire a conforming signal level in which the error is canceled by a simple process of obtaining the difference. Further, since the difference between the signal levels having the directivity in the opposite directions is taken, the change range of the adaptation signal level can be increased, and the reliability of the direction calculated by the direction calculation unit 55 is effectively improved. be able to.

  Although the embodiment of the present invention has been described above, the above configuration can be further modified as follows.

  The accuracy calculation unit 54 constructed in the analysis device 14 of the second embodiment is configured to cause the fitting processing unit 52 to perform the fitting process again after performing the threshold determination. Can be changed as appropriate. For example, the reliability of the calculated azimuth when the accuracy calculation unit 54 exceeds the predetermined threshold (or the total value) between the signal level for adaptation and the signal level calculated by the fitting function. It can also be configured to determine that is low. Further, when it is determined that the reliability of the calculation result is low, the processing for detecting the direction is stopped without causing the fitting processing unit 52 to re-process, and the result output unit 57 is changed to a configuration for outputting the fact. Can do. Or it can also change to the structure which displays on the result output part 57 that the accuracy of the said determination result is low with the calculation result of an azimuth | direction. Moreover, it can replace with the structure of 2nd Embodiment, and it can also comprise so that the accuracy calculation part 54 may determine the detection result of the azimuth | direction calculation part 55 afterwards. Thus, the configuration of the accuracy calculation unit 54 can be changed as appropriate according to circumstances.

  Also in the azimuth detection device 10 of the first embodiment, the accuracy calculation unit 54 can be constructed in the analysis device 14 as in the configuration of the second embodiment.

  In the above embodiment, the metal shielding plate 12 is used in order to make the directivity remarkable. However, the shape and material of the shielding member for attenuating the signal can be appropriately changed according to circumstances. Moreover, it can also be configured to detect an orientation by mounting an antenna on a part of a human body such as the head or torso, and a part of the human body functions as a shielding member. As described above, the shielding member may be any member that can be used to attenuate radio waves. In addition, the configuration can be changed to a configuration in which the shielding plate member is omitted and the direction is detected using the directivity of the patch antenna itself. Furthermore, the GPS antenna for receiving a signal from the GPS satellite 1 may be configured to have different sensitivity depending on an angle with respect to a predetermined direction, and is not limited to a configuration having directivity in one direction. In any case, a fitting function determined so as to reflect the characteristics of the GPS antenna that receives the signal needs to be obtained in advance and stored in the fitting function storage unit 53.

  The azimuth detecting device can also be configured to include three or more GPS antennas. In this case, if the characteristics of the GPS antenna are known, the number and arrangement of the GPS antennas can be changed as appropriate. For example, in a plan view, four GPS antennas may be arranged so as to be positioned at the apex of the rhombus.

  In addition, as the fitting function, functions other than those shown in Expression (1) and Expression (2) can be used. For example, sin θ (sine function) can be used as the fitting function. As described above, any appropriate function can be used as long as the fitting function is a function that can express the relationship between the direction and the signal level of the GPS antenna having the characteristic that the sensitivity of the signal varies depending on the direction.

  In the above-described embodiment, the fitting function for detecting the azimuth is obtained by preliminary measurement, but the azimuth detecting device 10 has a function of automatically performing preliminary measurement for deriving the fitting function. It can also be configured.

  Moreover, although the analysis apparatus 14 of the said embodiment is a general purpose personal computer, it can also be changed into the computer for exclusive use for detecting an azimuth | direction. Further, the analysis device, the GPS receiver, and the GPS antenna can be integrally configured to be configured as a handy type azimuth detection device having portability. As described above, the present invention can be applied to various configurations.

  Moreover, in the said embodiment, although it is the structure which detects the azimuth | direction of a GPS antenna based on the signal from the GPS satellite 1, it changes into the structure which detects an azimuth | direction using the global positioning system (GNSS) other than GPS. be able to.

1 GPS satellite (GNSS satellite)
11 GPS antenna (antenna)
10 Direction detecting device 21 First GPS antenna (first antenna)
30 Direction detecting device 31 Second GPS antenna (second antenna)
51 Satellite data input part (input part)
52 Fitting processing unit (processing unit)
53 Fitting function storage unit (storage unit)
54 Accuracy calculation unit 55 Direction calculation unit 56 Difference data acquisition unit (acquisition unit)

Claims (15)

A storage unit in which a function derived from the relationship between the reception angle of the signal of the antenna having directivity and the signal level is stored in advance;
An input unit to which the azimuth information and received signal level of the GNSS satellite acquired by the antenna based on the signal received from the GNSS satellite are input;
A processing unit that performs processing for adapting the function to the relationship between the azimuth information and the received signal level obtained for each GNSS satellite when the azimuth information and received signal level of a plurality of GNSS satellites are input to the input unit ,
An azimuth calculating unit for calculating the direction of the antenna based on a tendency of a calculated signal level calculated by a function adapted by the processing unit;
An azimuth detecting device comprising: The azimuth detecting device according to claim 1,
The bearing calculation unit
An azimuth detecting device, wherein the direction of the antenna is calculated based on azimuth information when the calculated signal level calculated by the function adapted by the processing unit is the highest or azimuth information when the signal level is the lowest. The direction detection device according to claim 1 or 2,
The azimuth detecting apparatus characterized in that the function includes a trigonometric function. It is an azimuth detecting device according to any one of claims 1 to 3,
An azimuth detection apparatus comprising: an accuracy calculation unit that calculates an accuracy of an azimuth calculated by the azimuth calculation unit based on a difference between the calculated signal level and the received signal level. The azimuth detecting device according to claim 4,
The accuracy calculation unit
An azimuth detecting device characterized in that the accuracy of a calculation result by the azimuth calculating unit is obtained by comparing a difference between the calculated signal level and the received signal level in the same azimuth with a threshold value. The azimuth detecting device according to claim 5,
When the difference between the calculated signal level and the received signal level exceeds a threshold value, the direction detecting device is characterized by excluding the received signal level exceeding the threshold value and re-adapting the function to the processing unit. A storage unit that stores in advance a function derived from the relationship between the signal reception level and the signal level of the antenna set in which a plurality of antennas having directivity are arranged according to a predetermined arrangement relationship;
An input unit to which azimuth information of the GNSS satellite viewed from a reference position acquired based on a signal received by the antenna from a GNSS satellite and a received signal level of a signal received by each antenna are input;
An acquisition unit that acquires a signal level for adaptation according to the direction of the GNSS satellite based on the received signal level of the signal received from the same GNSS satellite for each antenna;
When the azimuth information and reception signal level of a plurality of GNSS satellites are input to the input unit for each antenna, the function is adapted to the relationship between the azimuth information obtained for each GNSS satellite and the adaptation signal level. A processing unit for performing processing,
An azimuth calculating unit that calculates the orientation of the antenna set based on a tendency of a calculated signal level calculated by a function adapted by the processing unit;
An azimuth detecting device comprising: The azimuth detecting device according to claim 7,
The bearing calculation unit
An azimuth detecting device characterized in that the direction of the antenna set is calculated based on azimuth information when the calculated signal level calculated by the function adapted by the processing unit is the highest or azimuth information when the signal level is the lowest. The azimuth detecting device according to claim 7 or 8,
The azimuth detecting apparatus characterized in that the function includes a trigonometric function. The azimuth detecting device according to any one of claims 7 to 9,
An azimuth detection device comprising: an accuracy calculation unit that calculates an accuracy of an azimuth calculated by the azimuth calculation unit based on a difference between the calculated signal level and the adaptation signal level. The azimuth detecting device according to claim 10,
The accuracy calculation unit
An azimuth detecting device characterized in that the accuracy of a calculation result by the azimuth calculating unit is obtained by comparing a difference between the calculated signal level and the matching signal level in the same azimuth with a threshold value. The azimuth detecting device according to claim 11,
If the difference between the calculated signal level and the adaptation signal level exceeds a threshold value, the orientation detection is performed by excluding the adaptation signal level exceeding the threshold value and re-adapting the function to the processing unit. apparatus. The azimuth detecting device according to any one of claims 7 to 12,
The plurality of antennas includes a first antenna and a second antenna having directivity in opposite directions to each other,
The acquisition unit is configured to acquire a matching signal level by taking a difference between a received signal level received by the first antenna and a received signal level received by the second antenna. In a direction detection method for calculating the direction of an antenna having directivity,
A first step of deriving a function derived from a relationship between a reception angle of a signal of the antenna and a signal level;
A second step in which azimuth information and received signal level of the GNSS satellite acquired by the antenna based on a signal received from the GNSS satellite are input;
A third step of adapting the function to the relationship between the azimuth information and the received signal level obtained for each GNSS satellite when the azimuth information and the received signal level of a plurality of GNSS satellites are input;
A fourth step of calculating an orientation of the antenna based on a tendency of a calculated signal level calculated based on a function;
The direction detection method characterized by including. In an azimuth detection method for calculating the direction of an antenna set in which a plurality of antennas having directivity are arranged according to a predetermined arrangement relationship,
A first step of deriving a function derived from a relationship between a reception angle of a signal of the antenna set and a signal level;
A second step in which azimuth information of the GNSS satellite viewed from a reference position acquired based on a signal received by the antenna from a GNSS satellite and a received signal level of a signal received by each of the antennas are input; ,
A third step of obtaining a signal level for adaptation according to the direction of the GNSS satellite based on the received signal level of the signal received from the same GNSS satellite for each antenna;
A fourth step of adapting the function to the relationship between the orientation information obtained for each GNSS satellite and the adaptation signal level when orientation information and received signal levels of a plurality of GNSS satellites are input for each antenna. When,
A fifth step of calculating an orientation of the antenna set based on a tendency of a calculated signal level calculated by an adapted function;
The direction detection method characterized by including.

Images