JP2004184121A - Controller and server unit for gps receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a GPS receiver capable of efficiently capturing a GPS satellite. <P>SOLUTION: This GPS receiver is provided with a database 30 for storing mask information 31 an area by an area. A control part of the receiver reads out the mask information corresponding to a reception area of a GPS signal, and selects the GPS satellite to be captured, according to the mask information. The mask information is prepared based on a distribution of visible areas in the sky, and a selection prohibiting flag "1" is imparted in each invisible area to prohibit the GPS satellite navigating within the area from being selected as a captured object. A selection allowing flag "0" is imparted in the each visible area to allow the GPS satellite navigating within the area to be selected as the captured object. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device of a GPS receiver that captures a GPS (Global Positioning System) satellite and receives a GPS signal, and a server device that provides information to the control device.
[0002]
[Prior art]
As conventionally known, a GPS receiver receives GPS signals transmitted from a plurality of GPS satellites launched in orbit around the earth and analyzes navigation messages and the like included in the GPS signals. To derive its current position. In the case of three-dimensional positioning, at least four or more GPS satellites are acquired and GPS signals are received.
[0003]
Acquisition of a GPS satellite by a general GPS receiver is performed through a process of detecting a carrier frequency of a satellite signal transmitted from the GPS satellite and a process of detecting and synchronizing a code phase of the satellite signal. . The GPS receiver selects a GPS satellite to be used for positioning from the GPS satellites captured through these processes, and performs positioning calculation.
[0004]
By the way, the conventional GPS receiver attempts to capture a GPS satellite on the assumption that the sky is completely open (that is, the sky can be completely seen from the GPS receiver). In some cases, an attempt is made to acquire a GPS satellite to which a signal does not reach.
[0005]
In such a case, there is a problem that the time required for positioning becomes long because a GPS satellite that cannot receive a satellite signal attempts to acquire it wastefully. In addition, this is a cause of wasting power.
Note that, as a conventional technique, Patent Literature 1 discloses a technique in which a satellite selection prohibited range is set by an elevation angle to prevent deterioration of positioning time and the like. Patent Document 2 discloses a technique of detecting a visible obstacle in the sky using a camera and selecting a GPS satellite to be captured based on the detection result.
[0006]
[Patent Document 1]
JP-A-6-34738
[Patent Document 2]
Japanese Unexamined Patent Publication No. 2001-523006
[0007]
[Problems to be solved by the invention]
However, the former technique (Patent Document 1) described above is mainly intended to solve a problem when a GPS receiver is mounted on an observation balloon or the like. However, even if the present invention is applied to a terrestrial GPS receiver of a different type, there is a problem that an effective effect on the positioning time and the like cannot be obtained.
[0008]
For example, in an in-vehicle GPS receiver, the surrounding environment that causes radio interference, such as a high-rise building, changes every moment as the vehicle travels. It was more likely that satellite acquisition failed. In addition, it is conceivable to adjust the elevation angle that defines the satellite selection prohibited range based on the reception state of the satellite radio wave, but even if such a method is adopted, the satellite Since the setting of the prohibited range cannot be made in time, it has been difficult to effectively improve the performance of the GPS receiver.
[0009]
On the other hand, the latter technique (Patent Document 2) has a problem that it takes a long time to detect a visible obstacle because an image of a camera is analyzed to detect a visible obstacle. In particular, in a GPS receiver mounted on a mobile body such as an automobile, since a visible obstacle changes every moment, it has been difficult to constantly analyze an image captured by a camera and detect the visible obstacle. At night, there is a problem that a visible obstacle cannot be detected.
[0010]
The present invention has been made in view of such a problem, and has as its object to provide a GPS receiver control device capable of causing a GPS receiver to acquire a suitable GPS satellite, and a server device used for the control device. .
[0011]
[Means for Solving the Problems]
In the GPS receiver control apparatus according to claim 1, the satellite selection means is provided in accordance with the selection rule information corresponding to the receiving area of the GPS signal obtained from the database by the selection rule information obtaining means. Selects a GPS satellite to be captured from a plurality of GPS satellites traveling in the sky. The acquisition control means causes the receiving means of the GPS receiver to acquire the GPS satellite selected by the satellite selection means.
[0012]
In the present invention (Claim 1), since the selection rule information of each area is stored in the database and the selection rule information is provided to the control device of the GPS receiver, it is suitable for the GPS signal receiving area. The GPS satellite can be captured by the receiving means of the GPS receiver.
[0013]
Since the GPS satellites suitable for acquisition vary depending on the arrangement of the surrounding radio wave obstacle where the GPS receiver is located, the selection rule information is stored in a database for each region in this manner, and thereby the selection rules of the GPS satellites are stored. If can be changed for each region, a suitable GPS satellite can be captured by a GPS receiver mounted on a mobile body (vehicle such as an automobile, a portable terminal, or the like).
[0014]
As a result, according to the present invention, the time required for capturing a GPS satellite can be reduced, and the time required for positioning can be reduced. In addition, since the receiving means of the GPS receiver can cause the receiving means of the GPS receiver to acquire a GPS satellite suitable for the positioning calculation, the accuracy of the positioning calculation based on the GPS signal is improved.
[0015]
The control device of the GPS receiver may be incorporated in the GPS receiver, or may be configured to remotely control the receiving means of the GPS receiver wirelessly.
In addition, it is preferable that the receiving means of the GPS receiver capture a GPS satellite navigating in the visible region of the sky overlooking the GPS satellite, so that a suitable GPS signal can be received because of a less radio disturbance. Therefore, in the present invention, it is preferable to characterize the selection rule information based on the distribution of the sky visible region viewed from each area, and store the selection rule information in a database. By characterizing the selection rule information in this way, the GPS receiver can be operated so that the acquisition is performed on the GPS satellites navigating the visible region of the sky.
[0016]
According to the control device for a GPS receiver according to claim 2, which handles the selection rule information characterized based on the distribution of the sky visible region, The number of times GPS satellite acquisition fails can be significantly reduced. Therefore, according to the control device of the GPS receiver according to the second aspect, it is possible to suppress the power required for capturing a GPS satellite, and to operate the GPS receiver with a small amount of power.
[0017]
The database may store, as selection rule information, area information indicating a navigation area of a GPS satellite that can be selected as an acquisition target for each predetermined area. When such area information is stored in the database, the satellite selection means may be configured to select a GPS satellite to be captured from among GPS satellites navigating the navigation area represented by the area information. .
[0018]
According to the control device for a GPS receiver according to the third aspect of the present invention, it is not necessary to cause the receiving unit of the GPS receiver to execute the acquisition of the GPS satellite that is inappropriate as the acquisition target. Then, the GPS satellite can be efficiently acquired. Therefore, according to the present invention (claim 3), the power consumption of the GPS receiver can be suppressed.
[0019]
Further, if the navigation area of the GPS satellite represented by the area information is the visible area of the sky, the GPS signal transmitted from the GPS satellite traveling in the invisible area of the sky which cannot be seen from the ground can be used for positioning calculation. Thus, it is possible to suppress the occurrence of a positioning error due to the influence of a conventionally known multipath. Therefore, according to the control device of the GPS receiver having such a configuration, it is possible to perform positioning with higher accuracy than before.
[0020]
More preferably, the area information is configured as described in claim 4. The area information handled by the control device of the GPS receiver according to claim 4 is, for each area configured by dividing the sky represented by a two-dimensional coordinate system into a grid pattern, a GPS satellite navigating the area is acquired. Is provided with selectability information indicating whether or not selection is possible.
[0021]
According to this invention (claim 4), the sky is divided by representing the sky in a two-dimensional coordinate system, and the selectability information is given to each area. Therefore, the GPS satellite suitable for the GPS satellite to be captured is provided to the satellite selection means. Can be selected efficiently.
For example, it is possible to divide the sky by expressing it in a one-dimensional coordinate system, and to give area selectability information to form area information. In this case, however, it is possible to capture with one position parameter (such as elevation angle). An area that is appropriate as a target is represented using the selectability information. On the other hand, the distribution of high-rise buildings and terrain such as mountains and hills that cause radio interference on the ground is determined by the azimuth and elevation angle around the current position of the GPS receiver. That is, even if the sky is represented by a one-dimensional coordinate system, the information on the radio wave obstacle cannot be sufficiently reflected in the area information.
[0022]
It is also possible to divide the sky by expressing it in a three-dimensional coordinate system and to give each area selectability information to form area information. Such as shortening of positioning time).
On the other hand, if the area information is configured as described in claim 4, the information on the radio wave obstacle can be appropriately reflected in the area information with a small amount of information. In the case where the region information described in claim 4 is characterized based on the distribution of the visible region of the sky, for example, the visible region of the sky is classified as a region that can be selected by a GPS satellite as a capturing target, and the invisible region is captured. What is necessary is just to classify into the area | region which cannot be selected as a target, and to produce | generate area information.
[0023]
In this way, the GPS satellites that cannot be seen from the ground due to obstacles such as high-rise buildings and terrain can be excluded from the capture target, so that the performance degradation of the GPS satellites due to this can be prevented. . Further, the positioning error due to the multipath can be suppressed, and the accuracy of the positioning calculation based on the reception result of the receiving unit improves.
[0024]
In addition, as the selection rule information, the database may store selection order information indicating the selection order of the GPS satellites.
If such selection order information is stored in the database, the required number of GPS satellites can be captured by the receiving means of the GPS receiver in order from the preferred GPS satellites. For example, if the selection order of the GPS satellites having a low possibility of being captured is lowered, the time required for capturing the GPS satellites can be reduced, and the time required for positioning can be reduced.
[0025]
When the database stores the selection rule information including such selection order information, the satellite selection means may select a GPS satellite to be captured according to the selection order information included in the selection rule information. May be configured.
The selection order information is, as described in claim 6, priority information indicating the selection priority of the GPS satellites for each region formed by dividing the sky represented by a two-dimensional coordinate system into a grid. It is good to have composition provided with. Further, when the selection order information is configured in this manner, according to the selection order information included in the selection rule information obtained by the selection rule information obtaining means, the acquisition target is sequentially determined from the GPS satellites navigating in the area of the higher selection priority. It is preferable to configure the satellite selecting means so as to select the GPS satellite to be set.
[0026]
Although the sky can be represented by a one-dimensional coordinate system or a three-dimensional coordinate system and priority information can be given to each area, the sky is represented by two-dimensional coordinates and divided as in the present invention (claim 6). If the priority information is given to each area, the selection order information can be created by appropriately reflecting the distribution of the radio wave obstruction, similarly to the above-described invention. Therefore, it is possible to cause the receiving means of the GPS receiver to efficiently capture a suitable GPS satellite.
[0027]
In the case where the selection order information according to claim 6 is characterized based on the distribution of the visible area in the sky, for example, the selection priority is set higher in an area with a larger visible area, and the selection priority is set in an area with a smaller visible area. The priority information may be given to each of the divided areas in such a manner as to be lower. Further, priority information may be given to each of the divided areas so that the selection priority becomes higher from the invisible area to the visible area.
[0028]
In this way, it is possible to lower the selection priority of GPS satellites that cannot be seen from the ground due to obstacles such as high-rise buildings and terrain, and to suppress positioning errors due to multipath. Therefore, according to the GPS receiver control device having such a configuration, it is possible to reduce the time required for positioning and further improve the positioning accuracy.
[0029]
In addition, in the control device of the GPS receiver according to the first to sixth aspects, as described in the seventh aspect, for each GPS satellite selected by the satellite selection means, whether the reception means can capture that GPS satellite It is preferable to provide an information updating means for determining whether or not the selection rule information is stored in the database according to the determination result.
[0030]
According to the control device of the GPS receiver according to the seventh aspect, learning and updating of the selection rule information can be performed based on the capture result of the receiving means, and the receiving means of the GPS receiver can be used. , More suitable GPS satellites can be selectively acquired.
[0031]
As described above, the control device of the GPS receiver according to claims 1 to 7 has been described. However, the database described above is capable of bidirectional communication with the control device of the GPS receiver of the present invention as described in claim 8. It can be built in a simple server device.
When the database is incorporated in an external server device, selection rule information corresponding to the GPS signal reception area is requested to the server apparatus, and the selection rule information corresponding to the GPS signal reception area is obtained from the server device database. What is necessary is just to comprise the selection rule information acquisition means of Claim 1-Claim 7 so that it may acquire.
[0032]
If the database is incorporated in an external server device, it is not necessary to provide a recording medium such as a memory required for the database in the GPS receiver or its control device, so that the GPS receiver and its control device can be manufactured at low cost. is there. In order to obtain appropriate selection rule information from the server device side, it is necessary to provide the server device with position information indicating the reception area of the GPS signal by the receiving means of the GPS receiver together with the request for the selection rule information. , A selection rule information acquisition unit may be configured.
[0033]
The server device may be configured as described in claim 9 corresponding to the configuration of the control device described in claim 8. The server device according to the ninth aspect includes a database that stores the selection rule information for each predetermined area, and when a request for providing the selection rule information is received from the control device of the GPS receiver, the position information acquisition means. Acquiring position information indicating a GPS signal receiving area of the GPS receiver, and reading out selection rule information corresponding to the GPS signal receiving area of the GPS receiver from the database by the information providing means based on the position information. , And provides the selection rule information to the control device of the GPS receiver. According to this server device, the selection rule information can be provided to the control device of the GPS receiver according to the eighth aspect.
[0034]
It is preferable that the position information acquiring means is configured to acquire position information from a GPS receiver. When the server device and the control device of the GPS receiver communicate with each other via the wireless communication system, the wireless communication system controls the GPS receiver based on the reception state of the radio wave. The position information obtaining means may be configured to obtain the position information of the device from the wireless communication system.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram illustrating a configuration of a GPS receiver 1 according to a first embodiment including a control unit 20 to which the present invention is applied.
[0036]
The GPS receiver 1 according to the first embodiment mainly includes a receiving unit 10, a control unit 20, a database 30, and a communication interface 40.
The receiving unit 10 is connected to a receiving antenna 11, and appropriately amplifies a radio frequency signal received by the receiving antenna 11 and converts the signal into an intermediate frequency signal, and an intermediate signal output from the high frequency processing circuit 12. A data demodulation unit 13 for demodulating the frequency signal.
[0037]
The data demodulation unit 13 includes a plurality of demodulation circuits (channels 1 to N) 14 corresponding to the number (N) of GPS satellites to be simultaneously captured, and a maximum of N GPS satellites are transmitted from these GPS satellites. It is configured to be able to demodulate incoming satellite signals in parallel. In the case of three-dimensional positioning, generally, about 6 to 8 demodulation circuits 14 are provided.
[0038]
Each demodulation circuit 14 is controlled by the control unit 20, synchronizes with a satellite signal transmitted from a GPS satellite, and captures the GPS satellite. Then, a satellite signal transmitted from the captured GPS satellite is demodulated to obtain a GPS signal. Then, the demodulation result (GPS signal) is input to the control unit.
[0039]
Specifically, each of the N demodulation circuits 14 searches for the carrier frequency of the GPS satellite to be captured, and at the same time, transmits the satellite signal modulated by the spread spectrum code from the GPS satellite by synchronizing the code. A satellite signal is made spectrum despreadable to obtain a GPS signal.
[0040]
The control unit 20 includes a CPU 21 and a memory 23 (ROM, RAM) that stores a program for causing the CPU 21 to execute various processes to be described later, and performs overall control of each unit of the receiver. Specifically, the control unit 20 allocates GPS satellites to be captured to each demodulation circuit 14 (each channel) of the data demodulation unit 13 and controls each demodulation circuit 14 to transmit from each GPS satellite. The received GPS signal can be received. Then, a navigation message or the like included in the GPS signal is obtained from the receiving unit 10. As is well known, the navigation message includes various information required for positioning, such as almanac data corresponding to satellite orbit information and ephemeris data.
[0041]
The GPS receiver 1 includes a database 30 including a storage medium that can be read and written by the control unit 20. FIG. 2A is an explanatory diagram illustrating a configuration of the database 30. In the database 30, mask information 31 indicating a selection rule of a GPS satellite is associated with center position information (for example, latitude / longitude) and application range information (for example, application radius) indicating an application area of the mask information. Is stored for each application area. Each mask information 31 is used when the GPS receiver 1 is located in an area within the applicable range from the center position represented by the center position information.
[0042]
FIG. 2B is an explanatory diagram illustrating a data configuration of the mask information 31. This mask information 31 is created based on data (see FIG. 3B) relating to the distribution of the sky visible region collected in advance. FIG. 3B shows the sky in two-dimensional coordinates using the azimuth and the elevation angle as parameters, and shows the distribution of the sky visible area by filling the sky invisible area. FIG. 3B shows the distribution of the visible region of the sky corresponding to the area adjacent to the building, as shown in FIG. 3A. This type of data can be obtained by moving the camera toward the sky, photographing the sky, and analyzing the image.
[0043]
As shown in FIG. 3A, when a high-rise building is adjacent to the road, a GPS satellite located on an extension of a line connecting the GPS receiver 1 and the high-rise building (that is, GPS reception) The satellite signal cannot be satisfactorily received from a GPS satellite navigating in an invisible area of the sky that cannot be seen from the aircraft 1.
[0044]
Therefore, in this embodiment, the selection prohibition flag “1” is set in the sky invisible area and the selectable flag “0” is set in the visible area based on data on the distribution of the sky visible area collected in advance. Is set, and the mask information 31 is created. Note that these flags are information indicating whether a GPS satellite traveling in the corresponding area can be selected as a capture target.
[0045]
More specifically, in the present embodiment, the sky is represented by a two-dimensional coordinate system using the azimuth and the elevation angle as parameters, and the sky is divided into a grid at intervals of 15 degrees in the azimuth and 15 degrees in the elevation angle, and is configured by the division. The above flag was assigned to each area. However, in order to suppress the data amount of the mask information 31, the area is not divided by the azimuth at the elevation angle of 75 degrees or more.
[0046]
On the other hand, the GPS receiver 1 of the present embodiment including the database 30 specifically executes the processing shown in FIG. 4 to capture a GPS satellite and perform positioning calculation. FIG. 4 is a flowchart illustrating a main routine that is executed by the CPU 21 at the same time that the control unit 20 starts up the receiver 1.
[0047]
When the process is started, the control unit 20 stores the current position information indicating the current position of the receiver 1 obtained by the positioning calculation at the time of the previous operation and the satellite orbit information (almanac data or the like) used at that time. It is determined whether or not it is stored in the built-in memory 23 (S110).
[0048]
If it is determined that the data is not stored (No in S110), the process proceeds to S160. On the other hand, if it is determined that the information is stored (Yes in S110), the control unit 20 reads out the current position information and the satellite orbit information from the memory 23 (S120), and based on the current position information, It is determined whether the mask information 31 corresponding to the current position (that is, the GPS signal receiving area) exists in the database 30 (S130).
[0049]
In this process, the control unit 20 determines whether or not the GPS receiver 1 is present within the applicable range from the center position according to the center position information and the applicable range information associated with the mask information 31. Then, it is determined that the mask information 31 is the mask information 31 corresponding to the current position of the receiver 1.
[0050]
When determining that the corresponding mask information 31 does not exist in S130 (No in S130), control unit 20 shifts the processing to S160. On the other hand, if it is determined that the receiver 1 exists (Yes in S130), the control unit 20 obtains the mask information 31 corresponding to the current position of the receiver 1 from the database 30 (S140), and thereafter, selects the GPS satellite shown in FIG. The processing is executed (S150). FIG. 5 is a flowchart showing a GPS satellite selection process executed by the control unit 20 by the CPU 21.
[0051]
When the GPS satellite selection process is executed, the control unit 20 assumes that the sky is completely open (that is, there is no invisible area), and from among a plurality of GPS satellites traveling in the sky that can be seen from the GPS receiver 1. Then, one GPS satellite to be collated with the mask information 31 is selected (S151).
[0052]
After that, the control unit 20 compares the navigation area of the GPS satellite derived from the satellite orbit information with the mask information 31 so that the GPS satellite can be selected as a GPS satellite to be captured (hereinafter, “capable area”). It is determined whether the vehicle is traveling (S152). This determination is made by identifying the flag corresponding to the navigation area of the GPS satellite by using the mask information 31 acquired in S140.
[0053]
When determining that the navigation area of the GPS satellite is within the captureable area (that is, the flag of the area corresponding to the navigation position of the GPS satellite is “0”) (Yes in S152), the control unit 20 The GPS satellite is temporarily stored in a memory as a candidate for a GPS satellite to be captured (S153), and then the determination in S154 is performed.
[0054]
On the other hand, if it is determined in S152 that the navigation area of the GPS satellite is not the captureable area (that is, the flag of the corresponding area is “1”), the control unit 20 does not execute the processing of S153. The process proceeds to the determination of S154. In step S154, the control unit 20 determines whether or not the verification has been completed for all the GPS satellites to be verified. A check with the information 31 is performed.
[0055]
Then, when it is determined that the matching with the mask information 31 has been completed for all the GPS satellites to be matched (Yes in S154), the control unit 20 determines the specified number of GPS satellites that are acquisition candidates based on the matching result (S154). It is determined whether or not the number is equal to or more than 4 (S155). If the number is equal to or more than the specified number (Yes in S155), the receiving unit 10 is actually controlled from among the GPS satellites that have been captured candidates, and Then, a GPS satellite to be captured is selected (S156).
[0056]
When the number of GPS satellites that are candidates for capture is larger than the number of channels of the data demodulation unit 13, the number of GPS satellites to be captured is set to the number of channels (N) using a known DOP (Dilution Of Precision) value or the like. May be selected by the number corresponding to. When the number of GPS satellites that have been captured is less than the number of channels, all GPS satellites that have been captured may be selected as GPS satellites to be captured.
[0057]
On the other hand, if the control unit 20 determines in S155 that the number of GPS satellites that have been captured candidates is less than the specified number, the process proceeds to S157 and performs conventional satellite selection processing. In this conventional satellite selection process, a GPS satellite to be captured is selected on the assumption that the sky is completely open without using mask information. In this process, since a satellite may be selected by a known method, a specific description of the process will be omitted. For example, the DOP value is reduced, and the number of GPS All you have to do is select a satellite. When the selection of the satellite to be captured is completed in this way, the control unit 20 ends the GPS satellite selection process.
[0058]
Thereafter, the control unit 20 controls the reception unit 10 and allocates one GPS satellite selected by the GPS satellite selection process or the conventional satellite selection process to each demodulation circuit 14 of the data demodulation unit 13. Then, the receiving unit 10 performs the operation of capturing those GPS satellites (S170). Upon receiving this process, the receiving unit 10 attempts to capture each GPS satellite by detecting the carrier frequency and synchronizing the spread spectrum code as described above.
[0059]
Further, when the acquisition of the GPS satellites is completed in this way, the control unit 20 determines whether or not the GPS satellites more than the number necessary for the positioning are captured by the receiving unit 10 (S180), and the number required for the positioning is determined. If it is determined that the above GPS satellites have not been captured (No in S180), the process proceeds to S160, and a GPS satellite to be captured without mask information is selected. Then, the receiving unit 10 is caused to try capturing the GPS satellite again (S170).
[0060]
Then, when it is determined that the number of GPS satellites required for positioning has been captured (Yes in S180), the control unit 20 transmits a GPS signal that the receiving unit 10 continuously receives from the GPS satellites after capturing, from the receiving unit 10. The positioning calculation is performed by a known method using the acquired GPS signal (S190). Then, it updates its own current position according to the result of the positioning calculation, and outputs the current position information to the communication interface 40 (S200). The current position information output here is input to the navigation device 3 via the communication interface 40.
[0061]
Further, when the update of the current position is completed, the control unit 20 determines whether there is any GPS satellite that could not be acquired despite the attempt of the acquisition by the receiving unit 10 in response to the processing of S170 (S210). This determination can be realized by determining whether or not all the GPS satellites to be captured have been captured, based on the output result from the receiving unit 10.
[0062]
When it is determined that there is a GPS satellite that could not be captured (Yes in S210), the mask information 31 stored in the database 30 is updated according to the capture result (S220). In S220 of the first embodiment, the area in which the GPS satellite that could not be captured was determined is determined, and the flag corresponding to the navigation area of the GPS satellite is determined for the mask information 31 corresponding to the area in which capture was attempted. The mask information 31 of the database 30 is updated by rewriting the selectable flag “0” to the selectable flag “1” (S220).
[0063]
Thereafter, the control unit 20 determines whether or not a termination command has been input from the outside in response to a power-off command or the like (S230), and terminates the process if the termination command has been input. On the other hand, if it has not been input, the process proceeds to S130 again to determine whether or not there is mask information 31 corresponding to the updated current position of the GPS receiver 1. (S140, S150), and if not, a GPS satellite to be captured is selected by a conventional method without using the mask information 31 (S160). Then, for each selected GPS satellite, the receiving unit 10 attempts acquisition (S170), performs positioning calculation using the GPS signals that can be received by acquisition (S190), and updates the current position (S200).
[0064]
As described above, the GPS receiver 1 according to the first embodiment has been described. However, in the first embodiment, according to the mask information 31 corresponding to the reception area of the GPS signal, a target to be captured is selected from a plurality of GPS satellites traveling in the sky. Since the control unit 20 is configured to select a GPS satellite to be used and cause the receiving unit 10 to capture the selected GPS satellite, a suitable GPS satellite is efficiently transmitted to the receiving unit 10 according to the mask information 31 in each reception area. Can be captured. Therefore, according to this embodiment, the time required for capturing can be reduced, and the time required for positioning can be reduced.
[0065]
In particular, in the present embodiment, the mask information 31 for each area is characterized based on the distribution of the sky visible area viewed from the applicable area, and the GPS target to be captured is selected from the GPS satellites navigating the sky visible area. Since the control unit 20 is made to select a satellite and a GPS satellite that navigates in the invisible area and is likely to be unacquirable is not an acquisition target, it is possible to suppress the probability that the reception unit 10 fails to acquire a GPS satellite. it can.
[0066]
That is, according to the present embodiment, the receiving unit 10 does not needlessly perform a capturing operation, and the required number of GPS satellites can be captured by the receiving unit 10 in a shorter time than before. As a result, according to the present embodiment, it is possible to suppress the power required for capturing, and to suppress the power consumption of the GPS receiver 1. Further, in the present embodiment, since a GPS satellite traveling in the invisible area is not to be captured, a positioning error due to multipath can be suppressed, and the positioning accuracy of the GPS receiver 1 can be improved.
[0067]
In addition, according to the present embodiment, information about a selection rule (a flag indicating whether or not selection is possible) is added to each area configured by dividing the sky represented in a two-dimensional coordinate system into a grid, and Since the mask information 31 including the area information indicating the navigation area of the GPS satellites that can be selected as is created, the distribution of the visible area in the sky can be reflected in the mask information 31 in detail. Therefore, according to this embodiment, it is possible to cause the receiving unit 10 of the GPS receiver 1 to try to capture a GPS satellite that matches the actual distribution of the radio wave obstacle.
[0068]
Further, in the present embodiment, for each of the GPS satellites to be captured, it is determined whether or not the receiving unit 10 has captured those GPS satellites, and if there is any GPS satellite that has not been captured, the database 30 stores it. The control unit 20 is configured to update the mask information 31 (see S210 and S220), and the mask information 31 is updated based on the capture result by the reception unit 10. Therefore, according to the present embodiment, even if the distribution of the visible region changes due to a change in the external environment (new construction, etc.), it is possible to make the receiving unit 10 of the GPS receiver 1 always capture a suitable GPS satellite. .
[0069]
In the first embodiment, when a predetermined number of GPS satellites cannot be found in the visible region, a conventional satellite selection process is executed to select a GPS satellite regardless of the mask information 31. In this case, the mask information 31 cannot be effectively used. On the other hand, when the mask information 35 of the second embodiment described below is used instead of the mask information 31, the mask information can be effectively used even in an area having a small visible area although the data amount of the mask information increases. it can.
[0070]
Hereinafter, a second embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is an explanatory diagram illustrating a data configuration of the mask information 35 according to the second embodiment. FIG. 7 is a flowchart (a) showing the GPS satellite selection process executed by the control unit 20 of the second embodiment in S150 of the main routine and an explanatory diagram (b) showing a GPS satellite selection method.
[0071]
In the GPS receiver of the second embodiment, the configuration of the mask information 35 and the processing operation of the control unit 20 are partially different from those of the first embodiment, and the other configurations are the same as those of the first embodiment. Therefore, detailed description of each unit having the same configuration will be omitted. In addition, a part of the second embodiment will be described with reference to the drawings according to the first embodiment.
[0072]
In the database 30 of the GPS receiver in the second embodiment, instead of the mask information 31 of the first embodiment, mask information 35 having the configuration shown in FIG. For example, it is stored for each applicable area in association with latitude / longitude) and applicable range information (eg, applicable radius).
[0073]
The mask information 35 is characterized based on the data on the distribution of the visible region of the sky collected in advance as in the first embodiment. Specifically, the mask information 35 is created so that the selection priority of the GPS satellites is increased in the elevation direction from the invisible area of the sky to the visible area.
[0074]
In the second embodiment, the sky represented by a two-dimensional coordinate system using the azimuth and the elevation angle as parameters is divided into a grid at intervals of an azimuth of 15 degrees and an elevation angle of 15 degrees. The mask information 35 is created by giving a priority value indicating the selection priority of the satellite. However, in order to suppress the data amount of the mask information 35, the region is not divided by the azimuth at the elevation angle of 75 degrees or more. Further, the priority values are set to values of n + 1 steps (n = 4 in the figure) from 0 to n, and the smaller the value, the higher the selection priority.
[0075]
The control unit 20 of the GPS receiver according to the second embodiment including the mask information 35 executes the processes from S110 to S130 (see FIG. 4) as in the first embodiment. After reading the mask information 35 corresponding to the current position of the receiver (that is, the GPS signal receiving area), in S150, a GPS satellite selection process shown in FIG. 7A is executed.
[0076]
When the GPS satellite selection process is performed, the control unit 20 determines in S310 the GPS satellites navigating in the region of higher selection priority in order from among the plurality of GPS satellites navigating in the sky (that is, in each region of the mask information, The GPS satellites navigating in an area with a small assigned priority value are listed in order), and the GPS satellites are listed as acquisition candidates.
[0077]
For example, when the GPS satellites are traveling in the arrangement shown in FIG. 3B with respect to the mask information 35 shown in FIG. 6, the control unit 20 sets the GPS satellites as shown in FIG. .., G4, G3, G8, G4, G3, G7,. The result of the listing is temporarily stored in a built-in memory.
[0078]
After that, the control unit 20 selects the required number (the number of channels of the data demodulation unit 13) of the GPS satellites to be captured in order from the GPS satellites navigating in the region of high selection priority according to the result obtained in S310. . When it is not possible to select the GPS satellites to be captured only by the condition based on the priority value (for example, when the GPS satellites corresponding to the priority value 0 are equal to or more than the number of channels), the GPS satellites are sorted in descending order of the priority value. A well-known DOP value may be evaluated for a GPS satellite that cannot be selected only with a priority value while selecting, and a GPS satellite may be selected according to the evaluation result. Note that, in FIG. 7B, the GPS satellites to be captured when the number of channels N = 6 are surrounded by dotted lines.
[0079]
After selecting a GPS satellite in this way, the control unit 20 causes the receiving unit 10 to capture the selected GPS satellite to be captured, as in the first embodiment (S170). If the receiving unit 10 determines that a predetermined number or more of GPS satellites have been captured (Yes in S180), positioning calculation is performed using the GPS signals obtained from those GPS satellites (S190). Also, when there is no position information and no satellite orbit information (No in S110), when there is no mask information 35 (No in S130), and when the receiving unit 10 cannot capture more than a specified number of GPS satellites (No in S180). ), The conventional satellite selection processing is executed without the mask information, the GPS satellite selected by the selection is captured by the receiving unit 10 (S170), and the positioning calculation is performed (S190).
[0080]
Thereafter, the control unit 20 updates the current position (S200). If there is a GPS satellite that could not be acquired despite having made the receiving unit 10 attempt to acquire (Yes in S210), the mask information 35 stored in the database 30 is updated based on the acquisition result. (S220).
[0081]
As a method of updating the mask information 35, for example, with respect to the mask information 35 corresponding to the area where the receiving unit 10 attempted to acquire, the priority value of the area corresponding to the navigation area of the GPS satellite that could not be acquired is incremented by one. For example, there is a method of updating the mask information 35 in the direction of decreasing the selection priority.
[0082]
After updating the mask information 35 in this way, the control unit 20 determines whether an end command has been input, and if the end command has not been input (No in S230), the processing from S130 to S230 is repeatedly executed. . Then, when an end command is input (Yes in S230), the main routine ends.
[0083]
As described above, the operation of the GPS receiver according to the second embodiment has been described. In the present embodiment, based on the distribution of the visible region of the sky, each of the skys represented by the two-dimensional coordinate system is divided into grids. For each area, a mask information 35 is created by assigning a priority value as priority information indicating the selection priority of the GPS satellites, whereby information on the GPS satellite selection order is stored in the mask information 35, Since the control unit 20 is caused to select the GPS satellites in ascending order of the priority value, it is possible to cause the receiving unit 10 of the GPS receiver to acquire the required number of GPS satellites in order from the preferred GPS satellites.
[0084]
Also, in the second embodiment, in particular, since the priority value is assigned so that the selection priority becomes higher from the invisible area to the visible area, the GPS satellites to be captured are sequentially controlled from the GPS satellites navigating in the visible area. 20 can be selected to allow the receiving unit 10 to capture the GPS satellite. Therefore, according to the present embodiment, it is possible to suppress the number of times that the GPS satellite fails to be captured, and as a result, it is possible to reduce the time from the capture to the positioning and the power required for the capture. Further, according to the present embodiment, it is possible to cause the control unit 20 to perform the positioning while minimizing the influence of the multipath, and the positioning accuracy is improved.
[0085]
Further, in the present embodiment, similarly to the first embodiment, it is possible to create the mask information 35 that accurately reflects the actual distribution of the radio wave obstacle. Therefore, also for the GPS receiver in the second embodiment, the time from acquisition to positioning can be effectively reduced, and the power required for acquisition can be suppressed.
[0086]
In addition, in the present embodiment, similarly to the first embodiment, since the control unit 20 is configured so that the mask information 35 is updated based on the capture result by the receiving unit 10, it is always suitable regardless of changes in the external environment. GPS satellites can be captured by the GPS receiver.
[0087]
Next, the GPS receiver 51 of the third embodiment will be described. The GPS receiver 51 of the third embodiment has a configuration in which the database 30 is removed from the GPS receiver 1 of the first embodiment shown in FIG. In addition, the control unit 53 is configured to acquire the mask information 31 and 35 from the external server device 60 through the wireless communication device 5 connected to the navigation device 3.
[0088]
As described above, the configuration of the GPS receiver 51 of the third embodiment is substantially the same as that of the GPS receiver 1 of the first embodiment except that the database 30 does not exist and the processing operation in the control unit 53 is different. Since the configuration is the same, a detailed description of a portion relating to the same configuration will be omitted below.
[0089]
FIG. 8 is an explanatory diagram showing a communication system between the GPS receiver 51 and the server device 60. As shown in FIG. 8, the wireless communication device 5 is connected to the communication interface 40 of the GPS receiver 51 of the third embodiment via the navigation device 3.
[0090]
The wireless communication device 5 is connected via a cellular network 7 to a server device 60 connected to the cellular network 7 so as to be capable of two-way communication. The server device 60 is provided with a database 30 having the same configuration as that of the first embodiment shown in FIG. However, the database 30 of the server device 60 may store the mask information 35 shown in FIG. 6 instead of the mask information 31 shown in FIG.
[0091]
FIG. 9 is a flowchart showing a main routine executed by the control unit 53 of the GPS receiver 51 of the third embodiment by its own built-in CPU.
The control unit 53 of the GPS receiver 51 in the third embodiment is configured to be capable of bidirectional communication with the server device 60 through the wireless communication device 5, and when executing the main routine shown in FIG. It is determined whether or not the current position information and the satellite orbit information are present in the memory (S410). If it is determined that the information is present (Yes in S410), a request signal for the mask information 31, 35 is transmitted to the server device 60, and By transmitting its own current position information to the device 60 (S420), it requests the server device 60 for the mask information 31, 35 corresponding to the current position of the GPS receiver 51.
[0092]
On the other hand, when it is determined that either the current position information or the satellite orbit information does not exist (No in S410), the control unit 53 transmits a request signal for the mask information 31, 35 to the server device 60 (S430). .
When such a request is made, the mask information 31, 35 corresponding to the current position of the GPS receiver 51 is transmitted from the server device 60 by the processing of S640 or S680 described later. If the current position information is not transmitted to the server device 60, satellite orbit information is transmitted from the server device 60 in addition to the mask information 31 and 35 (see FIG. 10; details will be described later).
[0093]
Therefore, in S440, control unit 53 determines whether or not wireless communication device 5 has received the requested information from server device 60. When determining that the wireless communication device 5 has received the requested information (Yes in S440), the control unit 53 acquires the mask information 31 and 35 from the wireless communication device 5 and also transmits the satellite orbit information to its own. It is obtained from the received signal of the memory or the server device 60 (S445), and then executes the GPS satellite selection process (S450).
[0094]
When the mask information 31 having the structure shown in FIG. 2B is used, the control unit 53 causes the control unit 53 to execute the GPS satellite selection process shown in FIG. 5 in S450. When the mask information 35 having the structure shown in FIG. 6 is used, the control unit 53 is caused to execute the GPS satellite selection process shown in FIG.
[0095]
When the GPS satellite selection process ends, the control unit 53 advances the process to S470, and causes the receiving unit 10 to try to acquire the selected GPS satellite. When the acquisition of these GPS satellites is completed, in S480, it is determined whether or not the receiving unit 10 has acquired more than the specified number of GPS satellites required for positioning.
[0096]
Here, if it is determined that the GPS satellites equal to or more than the specified number have not been captured by the receiving unit 10 (No in S480), the control unit 53 shifts the processing to S460, executes the conventional satellite selection processing, and then proceeds to S470. The process is shifted to cause the receiving unit 10 to attempt to capture the GPS satellite selected by the conventional satellite selection process. Note that this conventional satellite processing is also executed when No is determined in S440.
[0097]
On the other hand, if it is determined that the specified number or more GPS satellites have been captured (Yes in S480), the control unit 53 shifts the processing to S490, and performs positioning by a known method using the GPS signals acquired from the reception unit 10. Perform calculations. Then, the current position is updated according to the calculation result (S500).
[0098]
Thereafter, the control unit 53 determines whether or not an end command has been input (S510). If the end command has been input, the process ends, and if not, the process proceeds to S420 and the end command is issued. Until the input, the processing of S420, S440 to S510 is repeated.
[0099]
On the other hand, the server device 60 of the third embodiment includes a communication unit 61 capable of two-way communication with an external GPS receiver 51 via the wireless communication device 5, and operates as shown in FIG. FIG. 10 is a flowchart illustrating an information providing process that is repeatedly executed by the server device 60 at all times. This information providing process is executed by the MPU 63 incorporated in the server device 60.
[0100]
After executing the information providing process, the server device 60 waits until the communication unit 61 connected to the cellular network 7 receives a request signal for the mask information 31 and 35 from the GPS receiver 51 (No in S610). Then, when it is determined that the request signal of the mask information 31, 35 has been received from the GPS receiver 51 (Yes in S610), it is determined whether the current position information has been transmitted from the GPS receiver 51 together with the request signal of the mask information 31, 35. Is determined (S620).
[0101]
Here, if it is determined that the current position information has been transmitted from the GPS receiver 51 (Yes in S620), the server device 60 acquires the current position information of the GPS receiver 51 from the received signal (S625). Then, based on the current position information, the mask information 31 and 35 corresponding to the current position of the GPS receiver 51 are read from the database 30 (S630). The reading method is the same as in the first embodiment.
[0102]
When the reading of the mask information 31, 35 is completed, the server device 60 shifts the processing to S640, and transmits the read mask information 31, 35 from the communication unit 61 via the cellular network 7 to the GPS receiver 51 of the request source. Send to After that, the process ends.
[0103]
On the other hand, if it is determined in S620 that the current position information has not been transmitted from the GPS receiver 51 (No in S620), the server device 60 transmits the current position information of the wireless communication device 5 from the cellular network 7 to the GPS receiver. 51 is acquired as the current position information (S650). In the CDMA wireless communication system, the position of the wireless communication device can be derived by analyzing the reception state of the radio wave at the wireless base station. It is assumed that the cellular network 7 of this embodiment is also provided with such a function.
[0104]
Thereafter, the server device 60 reads the mask information 31, 35 corresponding to the current position of the GPS receiver 51 from the database 30 based on the current position information acquired from the cellular network 7 (S660). Further, based on the current position information obtained from the cellular network 7, satellite orbit information of the GPS satellite corresponding to the position is created (S670). After that, the server device 60 transmits the satellite orbit information together with the mask information 31 and 35 from the communication unit 61 to the GPS receiver 51 via the cellular network 7 (S680), and ends the process.
[0105]
The GPS receiver 51 of the third embodiment and the server device 60 used for the same have been described above. However, in the present embodiment, the database 30 is provided in the server device 60, and the data is transmitted via the cellular network 7 as a wireless communication system. Since the control unit 53 of the GPS receiver 51 is configured to extract the mask information 31 and 35 from the database 30 of the server device 60, it is not necessary to store a large amount of mask information 31 and 35 in the GPS receiver 51. It is not necessary to incorporate a memory or the like in the GPS receiver 51. As a result, according to the third embodiment, the GPS receiver 51 can be manufactured at low cost.
[0106]
Further, if the database 30 is provided in the server device 60, the mask information 31, 35 can be updated by the server administrator, and the mask information 31, 35 accurately reflecting the actual distribution of the visible region. Can be provided to the GPS receiver 51. That is, in the method of updating the mask information 31 and 35 based on the captured result as in the first and second embodiments, when the distribution of the visible region in the sky changes due to the construction of a new building or the like, the GPS satellites are changed at least once. The capture will fail. On the other hand, if the server company manages the database 30, the mask information 31, 35 can be updated by collecting data in the visible region using a camera or the like, regardless of the results of capturing GPS satellites. 51 can be provided with highly reliable mask information 31 and 35.
[0107]
In this embodiment, the server device 60 is configured to acquire the current position information of the GPS receiver 51 from the cellular network 7 when the current position information cannot be acquired from the GPS receiver 51. Does not know the current position (for example, when the power is turned on and the current position information is not stored when the power was last turned off), the GPS satellite acquisition using the mask information 31 and 35 is performed. This can be performed by the receiver 51.
[0108]
The GPS receivers 1 and 51 of the first to third embodiments and the server device 60 used therein have been described above. However, the receiving unit of the present invention corresponds to the receiving unit 10 of the present embodiment, and the control of the present invention is performed. The device corresponds to the control units 20 and 53 incorporated in the GPS receivers 1 and 51. Further, the satellite selection means of the present invention is realized by a GPS satellite selection process (see FIGS. 5 and 7A) executed by the control units 20 and 53 of the present embodiment.
[0109]
Further, the acquisition control means of the present invention is realized by the satellite acquisition processing (S170, S470) executed by the control units 20, 53. Further, the selection rule information corresponds to the mask information 31, 35, and the selection rule information obtaining means performs the operation (S140, S420 to S445) in which the control units 20, 53 obtain the mask information 31, 35 from the database 30. Has been realized. In addition, the information updating means of the present invention is realized by the update processing (S210, S220) of the mask information 31, 35 executed by the control unit 20.
[0110]
Further, the position information acquisition means of the server device is realized by an operation (S625, S650) in which the server device 60 acquires the current position information from the GPS receiver 51 or the cellular network 7. In addition, the information providing means of the server device is realized by an operation (S640, S680) in which the server device 60 provides mask information to the GPS receiver 51.
[0111]
Further, the control device and the server device of the present invention are not limited to the above-described embodiment, but can adopt various aspects.
For example, the database 30 is not limited to the configuration illustrated in FIG. 2A, and may have a configuration illustrated in FIG. FIG. 11 is an explanatory diagram illustrating a configuration of the database 70 according to the modification. As shown in FIG. 11, the database 70 of the modification stores the mask information 31 with the center position information and the area type information in association with each other. The database 70 further stores an application range table 71.
[0112]
The application range table 71 includes application range information indicating the application range (applicable radius and the like) of the mask information 31 centered on the position indicated by the center position information for each preset region type. In addition, as an area | region type, an urban area, a mountain area, etc. are considered, for example.
[0113]
In this manner, when the mask information 31 is not directly associated with the application range information but is associated with the mask information 31 via the area type information, the data amount of the database 70 can be reduced as a whole. Also, as is generally known, the map database of the navigation device 3 stores area type information such as urban areas and mountain areas, so that the form of the database 70 as in the present embodiment may be adopted. If this is the case, the association with such information is simplified, and the cooperative operation with the navigation device 3 is facilitated. The database 70 may store the mask information 35 shown in FIG.
[0114]
When the GPS receiver is operated in cooperation with the navigation device, mask information 31 and 35 may be added to a map database incorporated in the navigation device and may be used instead of the databases 30 and 70. FIG. 12 is an explanatory diagram showing the configuration of a navigation device 90 provided with the mask information 31 in the map database 91 and a GPS receiver 81 connected thereto. In the map database 91 of the navigation device 90, the mask information 31 (see FIG. 2B) having the above-described configuration is stored in association with link information (link ID and the like) and node information (node ID and the like). .
[0115]
When executing the main routine, the control unit 83 of the GPS receiver 81 requests the navigation device 90 for the mask information 31 corresponding to the current position of the GPS receiver 81 in S130, and the mask information 31 Is transmitted via the communication interface 40 from the communication interface 40, it is determined that there is mask information corresponding to the current position (Yes in S130), and the mask information 31 is extracted from the transmission signal of the navigation device 90 (S140), and S150 Executes a GPS satellite selection process. On the other hand, when the mask information 31 is not transmitted from the navigation device 90, it is determined that there is no mask information (No in S130), and the conventional satellite selection process is executed (S160).
[0116]
On the other hand, the navigation device 90 functions as the server device of the present invention, and executes the information providing process shown in FIG. FIG. 13 is a flowchart illustrating an information providing process executed by the MPU 93 by the navigation device 90.
[0117]
The navigation device 90 is configured to be capable of bidirectional communication with the control unit 83 of the GPS receiver 81 via the communication interface 40, and receives a request for the mask information 31 from the control unit 83 of the GPS receiver 81 (S710). Yes), the current position information is acquired from the GPS receiver 81 (S720), and it is determined whether or not there is a link ID or a node ID corresponding to the current position information, and the mask information 31 corresponding to the current position information is determined. Is determined in the map database 91 (S730).
[0118]
When it is determined that the mask information 31 exists (Yes in S730), the mask information 31 associated with the link ID or the node ID corresponding to the current position information is read out (S740), and the current GPS information of the GPS receiver 81 is read. The mask information 31 corresponding to the position is transmitted to the GPS receiver 81 (S750). On the other hand, if there is no link ID or node ID corresponding to the position, for example, because the GPS receiver 81 is located off the road, the navigation device 90 displays the mask information 31 corresponding to the current position information. It is determined that it is not in the map database 91 (No in S730), and the fact that there is no mask information 31 is notified to the GPS receiver 81 (S760), and the process ends.
[0119]
By operating the navigation device 90 in this manner, even when the mask information 31 is stored in the map database 91, it is suitable for the GPS receiver 81 as in the invention according to the first and second embodiments. GPS satellites can be captured. In the above-described embodiment, the example in which the navigation apparatus 90 reads the mask information 31 based on the current position information obtained from the GPS receiver 81 has been described. The navigation device 90 may be configured to read the mask information 31 and 35 using position information obtained from a position detector such as a gyroscope.
[0120]
In addition, when a route to the destination is set in the navigation device 90, the control unit 83 of the GPS receiver 81 may be configured to use the route information. That is, the mask information 31 along the route is read from the navigation device 90 together with the route information, and on the assumption that the GPS receiver 81 moves along the route, the optimal combination of the GPS satellites to be captured is determined by the mask. The control unit 83 may be configured to select based on the information 31.
[0121]
In this way, it is possible to predict the GPS satellites that cannot be acquired in the near future based on the mask information 31. Therefore, it is possible to exclude the GPS satellites that will be unable to be acquired from the acquisition targets. If the GPS receiver 81 is configured in this manner, the number of times of capturing GPS satellites can be reduced, so that the GPS receiver 81 can be operated with low power consumption.
[0122]
Further, in the third embodiment, the GPS receiver 51 is configured to sequentially acquire the mask information 31 from the server device 60. However, when a route is set in the navigation device 3, the GPS receiver 51 follows the route. The control unit 53 may be configured to collectively request the mask information 31 to the server device 60 and collectively acquire the corresponding mask information 31 from the server device 60.
[0123]
In addition, in the first embodiment described above, the method of comparing each GPS satellite with the mask information 31 to list capture candidates and selecting a GPS satellite to be actually captured from the list is described as an example. The method of selecting a satellite is not limited to this method. For example, after a combination of GPS satellites to be captured is derived by a known method, whether or not the GPS satellite is an appropriate GPS satellite to be captured may be evaluated based on the mask information 31. Then, if there is an inappropriate GPS satellite, a combination of GPS satellites to be captured may be derived again by a known method, excluding the GPS satellite.
[0124]
In the second embodiment, priority values 0 to 4 are assigned to the respective regions and the priority information of the GPS satellites is stored in the mask information 35. For example, values 0 to 3 are handled as selectable flags, and 4 is treated as a selection prohibition flag, and the control unit 20 is configured not to select a GPS satellite in an area to which the value “4” is added as an acquisition target. It is possible to cause the control unit 20 to select the GPS satellites in the selectable area in the descending order of the selection priority while sorting.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a configuration of a GPS receiver 1 according to a first embodiment to which the present invention has been applied.
FIG. 2A is an explanatory diagram illustrating a configuration of a database 30 and FIG. 2B is an explanatory diagram illustrating a configuration of mask information 31.
FIG. 3 is an explanatory diagram relating to a method for creating mask information 31 based on the distribution of visible regions in the sky.
FIG. 4 is a flowchart illustrating a main routine executed by a control unit 20 of the GPS receiver 1.
FIG. 5 is a flowchart illustrating a GPS satellite selection process according to the first embodiment, which is executed by the control unit 20;
FIG. 6 is an explanatory diagram illustrating a configuration of mask information 35 according to the second embodiment.
FIGS. 7A and 7B are a flowchart (a) showing a GPS satellite selection process executed by the control unit 20 of the second embodiment and an explanatory diagram (b) showing a GPS satellite selection method.
FIG. 8 is an explanatory diagram illustrating a configuration of a GPS receiver 51 and a server device 60 according to a third embodiment.
FIG. 9 is a flowchart illustrating a main routine executed by a control unit 53 of the GPS receiver 51.
FIG. 10 is a flowchart illustrating an information providing process that is repeatedly executed by the server device 60 at all times.
FIG. 11 is an explanatory diagram illustrating a configuration of a database 70 according to a modification.
FIG. 12 is an explanatory diagram showing a configuration of a navigation device 90 provided with mask information 31 in a map database 91 and a GPS receiver 81 connected thereto.
FIG. 13 is an explanatory diagram illustrating an information providing process executed by the navigation device 90.
[Explanation of symbols]
1, 51, 81: GPS receiver, 3, 90: Navigation device, 5: Wireless communication device, 7: Cellular network, 10: Receiving unit, 11: Receiving antenna, 12: High frequency processing circuit, 13: Data demodulating unit, 14 demodulation circuit, 20, 53, 83 control unit, 30, 70 database, 31, 35 mask information, 40 communication interface, 60 server device, 61 communication unit, 71 application range table, 91 Map database

Claims (9)

Satellite selecting means for selecting a GPS satellite to be captured from a plurality of GPS satellites navigating in the sky;
Capture control means for capturing GPS satellites and receiving means for receiving a GPS signal transmitted from the GPS satellites, the capture control means for causing the reception means of the GPS receiver to capture the GPS satellites selected by the satellite selection means. ,
A GPS receiver control device comprising:
A selection rule information acquisition unit that acquires selection rule information corresponding to a reception area of a GPS signal by the reception unit from a database that stores selection rule information representing a selection rule of a GPS satellite for each predetermined area,
The GPS receiver selects a GPS satellite to be captured from among the plurality of GPS satellites navigating in the sky according to the selection rule information obtained by the selection rule information obtaining unit. Control device. 2. The GPS receiver according to claim 1, wherein each of the selection rule information stored in the database is characterized based on a distribution of a visible region of a sky viewed from an area corresponding to the selection rule information. 3. Control device. The selection rule information includes area information indicating a navigation area of a GPS satellite that can be selected as an acquisition target,
The satellite selecting means captures, from among the plurality of GPS satellites navigating in the sky, a GPS satellite navigating a navigation area represented by the area information included in the selection rule information acquired by the selection rule information acquiring means. 3. The GPS receiver control device according to claim 1, wherein a target GPS satellite is selected. The area information is, for each area formed by dividing the sky represented by a two-dimensional coordinate system into a grid pattern, whether or not a GPS satellite navigating the area can be selected as an acquisition target. The control device for a GPS receiver according to claim 3, further comprising information. The selection rule information includes selection order information indicating a selection order of GPS satellites,
The satellite selection means selects a GPS satellite to be captured according to the selection order information included in the selection rule information obtained from the database by the selection rule information obtaining means. Item 5. The control device for a GPS receiver according to any one of Items 4. The selection order information is provided with priority information indicating a selection priority of a GPS satellite for each region configured by dividing the sky represented by a two-dimensional coordinate system into a grid,
The satellite selecting means selects the GPS satellites to be captured in order from the GPS satellites navigating in the region of high selection priority according to the selection order information included in the selection rule information acquired by the selection rule information acquiring means. The control device for a GPS receiver according to claim 5, wherein Information updating means for determining, for each GPS satellite selected by the satellite selecting means, whether or not the receiving means has captured the GPS satellite, and updating the selection rule information stored in the database according to the determination result; The control device for a GPS receiver according to any one of claims 1 to 6, further comprising: The control device of a GPS receiver according to any one of claims 1 to 7, wherein the control device is capable of two-way communication with an external server device including the database.
The selection rule information acquisition unit requests the server device for selection rule information corresponding to a GPS signal reception area of the reception unit, and selects selection rule information corresponding to the GPS signal reception region from a database of the server device. A control device for a GPS receiver, characterized in that the control device is configured to be able to obtain a GPS receiver. A server device capable of two-way communication with the control device of the GPS receiver according to claim 8,
A database for storing, for each predetermined area, selection rule information representing a selection rule of a GPS satellite;
Position information obtaining means for obtaining position information indicating a reception area of a GPS signal by the GPS receiver when there is a request to provide selection rule information from the control device of the GPS receiver;
Based on the position information obtained by the position information obtaining means, the selection rule information corresponding to the GPS signal reception area of the GPS receiver is read from the database, and the selection rule information is provided to the control device of the GPS receiver. Information providing means to
A server device comprising:

Images