JP2012112815A - Satellite state determination method and software - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a satellite state determination method by which improving positioning effect of a global positioning system and preventing the positioning effect from decreasing are possible.SOLUTION: An inventive satellite state determination method includes: a step for detecting a first signal change slope in a first observation time of a current target satellite; a step for determining whether or not the current target satellite is a satellite to be shielded by the first signal change slope; and a step for presenting a state correlated if the current target satellite is the satellite to be shielded. As it can be determined whether or not the current target satellite is the satellite to be shielded by the satellite's signal intensity and state in which signals are received when a user uses a positioning device, a positioning effect can be prevented from decreasing when the signal intensity of the satellite is weakened.

Description

  The present invention relates to a satellite state determination method, and more particularly to a method for determining a satellite state based on a change slope of a signal from the satellite.

  The Global Positioning System (abbreviated as GPS) is a system that receives signals from four positioning satellites in the sky with a positioning device (GPS receiver) and knows the current position of a positioning target. The signal transmitted from the positioning satellite includes coordinate information regarding the position of the positioning satellite itself and time information when the signal is transmitted. The positioning chip mounted on the positioning device calculates the current position of the positioning target based on the coordinate information and the time information.

  When the global positioning system performs positioning through four positioning satellites, an error may occur in positioning if one satellite fails. When a signal is transmitted from the positioning satellite to the positioning device, the signal is blocked by the terrain shielding action, or the relative position between the four positioning satellites and the positioning device changes, which also causes an error in positioning. Cause.

  Satellite-based satellite navigation augmentation system (Satellite Based Augmentation System, abbreviated as SBAS), Assisted Global Positioning System (abbreviated as AGPS), Differential Global Positioning System (abbreviated as DGPS), etc. Has the disadvantage that the positioning action cannot occur unless it is far from the ground transmission tower or within the effective range of the satellite signal. In addition, since the signal strength becomes weak in an environment where the signal is shielded, the positioning operation cannot be surely caused.

  In order to improve the positioning effect of the global positioning system, the present invention provides a global positioning system that can make positioning accurate even if a signal is blocked.

  A main object of the present invention is to provide a satellite state determination method capable of improving the positioning effect of the global positioning system and avoiding the deterioration of the positioning effect.

  In order to solve the above-described problems, the present invention provides a satellite state determination method including the following steps. A step of detecting a first signal change slope within a first observation time of the current target satellite; and a step of determining whether the current target satellite is a satellite to be shielded by the first signal change slope; Providing a satellite state determination method including the step of presenting a correlated state if the current target satellite is a satellite to be shielded.

  According to the satellite state determination method of the present invention described above, it is possible to determine whether the current target satellite is a satellite to be shielded according to the signal intensity of the satellite and the state of acquiring the signal when the user uses the positioning device. . Therefore, it can be avoided that the positioning effect is deteriorated when the signal strength of the satellite becomes weak.

It is a flowchart which shows the method of selecting the target satellite which concerns on 1st embodiment of this invention. It is a flowchart which shows the method of judging the deterioration state of the satellite which concerns on 1st embodiment of this invention. It is a flowchart which shows the selection method of the satellite which should be shielded based on 1st embodiment of this invention. It is a flowchart which shows the method which escapes from the state which the target satellite which concerns on 1st embodiment of this invention should block. It is a flowchart which shows the judgment method which concerns on 2nd embodiment separately. It is a flowchart which shows the judgment method which concerns on 2nd embodiment separately.

  Hereinafter, embodiments of the present invention will be described in detail. In order to simplify the description of the present invention, hereinafter, a satellite capable of reliably transmitting a signal to the positioning device is defined as an effective satellite, and the number of effective satellites in the sky is indicated by N1. In order to remove hygiene that has poor observation characteristics among multiple satellites, the number of satellites is limited by limiting the elevation angle range and signal intensity. A satellite that meets the restriction conditions is defined as an observation satellite, and the number of observation satellites is indicated by N2. Since the positioning device selects four satellites from among a plurality of satellites and performs positioning, the four satellites are defined as positioning satellites. The relationship between the number of effective satellites N1, the number of observation satellites N2, and the number of positioning satellites 4 is N1 ≧ N2 ≧ 4.

  FIG. 1 is a flowchart showing a method for selecting a target satellite according to the first embodiment of the present invention. In the method for selecting a target satellite shown in FIG. 1, first, the positioning device observes an effective satellite (S221). Next, an observation satellite is selected according to the first condition input to the positioning device (S223). Next, a target satellite is selected from the observation satellites (S225). Next, it is inspected whether the signal of the target satellite is blocked or not (S227).

  The first condition can be determined by the elevation angle of the satellite or the intensity of the signal from the satellite. When the elevation angle of the satellite is included in the first condition, the range of the elevation angle can be set to 0 to 90 degrees. Preferably, the range of the elevation angle is 10 to 90 degrees. When the signal strength is included in the first condition, a carrier-to-noise ratio (abbreviated as CN ratio) can be set to 12 to 52 decibels (abbreviated as decibel, dB). .

  FIG. 2 is a flowchart illustrating a method for determining a satellite deterioration state according to the first embodiment of the present invention. In the method for determining the deterioration state of the satellite shown in FIG. 2, first, a change slope of the first signal transmitted from the effective satellite within the first observation time Δt1 is obtained (S31). Next, it is determined whether the satellite information from the target satellite is blocked by the change slope of the first signal (S33). Next, it is determined whether or not the positioning device shields satellite information from the target satellite or whether information for presentation is generated (S35). Next, according to the setting of the positioning device, the presentation information is transmitted to the upstream processing module (for example, a positioning information providing unit that realizes the positioning function by hardware or software such as a positioning chip) or the downstream processing module (for example, application software). Thus, the two processing modules are used (S37). In the above-described embodiment, first, it is determined whether or not the change slope of the first signal is deteriorated. When the change slope of the first signal deteriorates, the satellite information transmitted from the target satellite is blocked. That is, the satellite information from the target satellite is deleted or discarded.

  In the present embodiment, the determination of the deterioration state of the satellite with respect to the observation satellite is to reduce the resource for determination. When the resources for determination are sufficient, it is preferable to determine the deterioration state of the satellite with respect to the effective satellite.

  The processing method performed after the presentation information is generated in step S35 in FIG. 2 can be classified into two types according to the processing module and the determination module. A kind of processing method is a method of shielding a positioning signal from a positioning satellite having a problem. In other words, this is a processing method in which the determination result is transmitted to the upstream processing module so that the upstream processing module selects other positioning satellites to obtain positioning information. The other type uses the positioning signal from the original positioning satellite in question, but it is used when there is a possibility that the positioning signal from the positioning satellite may be interfered by using auxiliary information installed in the post-processing module. It is a method to inform the person. In this case, the user is informed that there is a possibility that the positioning signal at a specific time may cause an error in positioning accuracy due to the influence of signal strength or the like.

  FIG. 3 is a flowchart showing a method for selecting a satellite to be shielded according to the first embodiment of the present invention. In the method of FIG. 3, the first observation time Δt1 is defined as the time between the first time T1 and the second time T2. First, the first signal strength CNRt1 is detected at the first time T1, and the second signal strength CNRt2 is detected at the second time T2 (S321). Next, based on the first signal strength CNRt1 and the second signal strength CNRt2, it is determined whether the change slope CNRslope of the first signal of the current target satellite deteriorates within the first observation time Δt1 (S322). . Next, if the change slope CNRslope of the first signal of the target satellite deteriorates, it is further determined whether or not the current target satellite is a positioning satellite used in the positioning device (S323). Next, if the target satellite is a positioning satellite used in the positioning device, the target satellite is set as a satellite to be shielded (S324).

  When the change slope CNRslope of the first signal of the target satellite deteriorates, that is, a negative signal change slope appears, and the signal change slope is a predetermined signal change slope (for example, −3 is set to a predetermined signal change slope). It will be explained that the signal intensity from the target satellite is very deteriorated when the number of times reaches a predetermined number (for example, 3 times is set to a predetermined number). When the target satellite belongs to four positioning satellites for positioning, the target satellite is made a satellite to be shielded. The first time t1, the second time t2, the numerical value of the predetermined signal change slope, the number of times, and the like of the above-described embodiment are a kind of examples selected from various examples. In actual application, it is not limited to the above-described example, and can be freely selected according to demand.

  The core steps described in the following part will be described based on observation satellites selected according to preset first conditions. That is, after selecting an observation satellite, a change slope of a signal within a specific time is detected based on a change in the intensity of the signal from the observation satellite. If the change slope of the signal from the positioning satellite that provides the positioning information among the observation satellites becomes worse, this positioning satellite may not be used, or there may be a large error in the positioning information transmitted from the positioning satellite. Present.

  FIG. 4 is a flowchart illustrating a method for removing the target satellite from the state to be shielded according to the first embodiment of the present invention. The intensity of the signal from the target satellite varies according to the relative position change between the satellite and the positioning device. Therefore, even if the target satellite becomes a satellite to be shielded, the signal intensity from the target satellite is continuously measured to detect the change slope of the second signal within the second observation time (S331). Next, it is determined whether or not the target satellite is out of the state to be shielded by determining whether or not the change slope of the second signal is improved (S332). The process of determining whether or not the target satellite is to be removed from the state to be blocked can be referred to the contents of FIG. 2 and will not be described again in this embodiment.

  The length of the second observation time and the length of the first observation time may be the same or different. In the method of determining the change slope of the second signal, the superiority or inferiority of the signal is determined by setting a positive slope to a predetermined value. The satellite state determination method of the present invention is not a method used in place of the conventional global positioning system, but a method for assisting the conventional global positioning system. That is, it is determined whether or not the positioning signal from the positioning satellite is applied to the positioning device. If the signal change slope deteriorates, it is determined that the observation satellite being observed is not applicable to the positioning device, and the observation satellite is presented as a satellite to be shielded.

  After determining whether the target satellite is a satellite to be shielded, the determination result is transmitted to the processing module used through the target satellite.

  FIG. 5A and FIG. 5B are flowcharts separately showing the determination method according to the second embodiment. In the flowchart of FIG. 5A, first, all the positioning satellites capable of acquiring a signal to be transmitted are detected, and a list of a plurality of positioning satellites is created (S401). Next, an observation satellite is selected from the list of positioning satellites under the condition that the elevation angle ≧ 20 degrees (S402). Next, an observation satellite is selected when the intensity of the satellite signal becomes 20 to 50 decibels (S403). Next, a necessary target satellite is selected from the selected observation satellites (S410).

  First, the first observation time is determined by setting the 0th second as the first time and the 15th second as the second time on the target satellite. That is, the first signal change slope of the target satellite is detected within the first observation time between the first time and the second time (S404). Next, the first signal change slope to be detected is compared with the standard signal change slope to determine whether or not the first signal change slope ≦ −3 (S405). Since -3 is just a general example, other numbers may be selected and used according to practical demand. If the first signal change slope is larger than −3, it is explained that the signal intensity from the target satellite is normal. Therefore, another observation satellite is selected and its state is judged (S410).

  When the first signal change slope is ≦ −3, the first counter is used to count the number of times the first signal change slope is matched with the signal deterioration judgment condition, and the number of times counted by the first counter is recorded. (S407). Next, it is determined whether or not the number of times counted by the first counter reaches a preset count. For example, it is determined whether or not it reaches twice (S408). Next, when the number counted by the first counter reaches a preset count, another target satellite is selected and its state is judged. Next, it is determined whether the target satellite is a positioning satellite (S409). When the target satellite is not a positioning satellite, it is not necessary to consider the influence of the target satellite on the positioning information. When the target satellite is a positioning satellite, the target satellite is set as a satellite to be shielded (S411).

  The above-described determination can be performed by DOP (Dilution of Position). First, the absolute value of the DOP difference between two times (fifth second and zeroth second) is calculated (S412). It is determined whether or not the absolute value of the DOP difference ≧ preset value (for example, 0.1) (S413). If the absolute value of the DOP difference ≧ the preset value, the number of times is recorded by the second counter (S414). If the absolute value of the DOP difference is smaller than the preset value, the process returns to step S410. Next, it is determined whether the number of times counted by the second counter is larger than a preset value (S415). When the number of times counted by the second counter is larger than the preset value, the state of shielding the signal from the target satellite is maintained (S416).

  Next, the second signal change slope within the second time observation time of the target satellite is calculated (S417). Next, the second signal change slope is compared with a preset condition, for example, it is determined whether or not the second signal change slope ≧ −2 (S418).

  If the second signal change slope is greater than or equal to −2, it will be explained that the strength of the signal transmitted from the target satellite is improved. Observe the state of the observation satellite continuously. In order to ensure that the signal strength from the target satellite is not temporarily improved, the number of times the positioning satellite signal strength is improved is recorded by the third counter, and positioning is performed after several minutes or hours. Whether the signal intensity of the satellite is improved is counted, and the number of times of improvement is counted by the third counter (S419). Next, it is determined whether the number of times counted by the third counter exceeds a preset value (S420). If the number of times of counting exceeds the preset numerical value, it is explained that the target satellite providing the positioning information is not a satellite to be shielded, so the process returns to step 410 to determine the state of other observation satellites. If the second signal change slope is smaller than −2, the process returns to step 412.

  When it is detected in step S411 and step S416 that the signal strength of the positioning satellite is deteriorated, the positioning satellite is not only made to be a satellite to be shielded, but is also intended to be shielded as in the core step described above. Tell other processing modules how to present.

  When a chip having a global positioning function selects a positioning satellite, it usually does not provide a function for selecting a positioning satellite in a subsequent system. Therefore, even if the system determines that the current satellite is a satellite to be shielded, the result may be transmitted to the chip. The positioning device can present information about the signal status to the user through software. For example, the positioning information obtained at this time can be presented to the user through a voice, an alarm screen, or the like that there is a possibility that the signal strength from the positioning satellite is lowered and an error occurs in the positioning information.

  In the embodiment described above, the global positioning system has been described as an example. However, the present invention is not limited to the embodiment. For example, in various electronic devices driven through computer software, the satellite state determination method of the present invention can be implemented by an electronic device having a positioning / acquisition function by executing software stored in a memory. That is, as a result of detecting the first signal change slope within the first observation time of the target satellite and determining whether the current target satellite is a satellite to be shielded by the first signal change slope, Is determined to be a satellite to be shielded, the electronic device indicates that the current target satellite is a satellite to be shielded.

  According to the satellite state determination method of the present invention described above, it is possible to determine whether the current target satellite is a satellite to be shielded according to the signal intensity of the satellite and the state of acquiring the signal when the user uses the positioning device. . Therefore, it can be avoided that the positioning effect is deteriorated when the signal strength of the satellite becomes weak.

Claims (20)

Detecting a first signal change slope within a first observation time of the current target satellite;
Determining whether the current target satellite is a satellite to be blocked by the first signal change slope;
Presenting a correlated state when the current target satellite is a satellite to be shielded. Selecting a plurality of observation satellites from a plurality of satellites according to a first condition;
The satellite state determination method according to claim 1, further comprising: observing all observation satellites and setting one observation satellite as a target satellite.   The satellite condition determination method according to claim 2, wherein the first condition includes a condition in which a satellite elevation angle is 0 to 90 degrees.   3. The first condition according to claim 2, wherein the first condition includes a condition in which a carrier-to-noise ratio (abbreviated as a CN ratio) of a transmitted satellite signal is 12 to 52 decibels. Satellite state judgment method.   The first signal change slope of the target satellite is determined by the ratio of the carrier wave and noise of the signal from the satellite signal. If the first signal change slope is smaller than a preset value, the target satellite is determined as a satellite to be shielded. The satellite state determination method according to claim 4, wherein:   2. The satellite state determination method according to claim 1, wherein a positioning signal transmitted from the target satellite is shielded by the presented information.   The satellite state determination method according to claim 1, wherein an error is likely to occur in the positioning information depending on the information to be presented. The step of determining whether the current target satellite is a satellite to be shielded due to a change in signal strength is:
The satellite state of claim 1, comprising: determining whether the first signal change slope is good; and making the current target satellite a satellite to be blocked if the first signal change slope deteriorates. Judgment method. Detecting a second signal change slope within a second observation time of the target satellite;
2. The satellite state determination method according to claim 1, further comprising the step of determining whether the current target satellite is a satellite to be shielded based on a determination result with respect to the second signal change slope.   The satellite state determination method according to claim 1, further comprising the step of providing the presentation information to a pre-stage processing module or a post-stage processing module.   The satellite state determination method according to claim 10, wherein the upstream processing module is a positioning information providing unit, and the downstream processing module is software. In software that causes an electronic device to perform a satellite state determination method when software stored in a memory is driven, the satellite state determination method includes:
Detecting a first signal change slope within a first observation time of the current target satellite;
Determining whether the current target satellite is a satellite to be blocked by the first signal change slope;
Presenting a correlated state if the current target satellite is a satellite to be shielded. Selecting a plurality of observation satellites from a plurality of satellites according to a first condition;
13. The computer software of claim 12, further comprising: observing all observation satellites to make one observation satellite a target satellite.   The computer software according to claim 13, wherein the first condition includes a condition in which a satellite elevation angle is 0 to 90.   The first condition includes a condition in which a carrier-to-noise ratio (abbreviated as CN ratio) of a transmitted satellite signal is 12 to 52 decibels. Computer software.   The first signal change slope of the target satellite is determined by the ratio of the carrier wave and noise of the signal from the satellite signal. If the first signal change slope is smaller than a preset value, the target satellite is determined as a satellite to be shielded. The computer software according to claim 15, wherein:   13. The computer software according to claim 12, wherein the positioning signal transmitted from the target satellite is shielded by the presented information.   13. The computer software according to claim 12, wherein the computer software presents that there is a possibility that an error occurs in positioning information depending on the information to be presented. The step of determining whether the current target satellite is a satellite to be shielded due to a change in signal strength is:
13. The computer software of claim 12, comprising: determining whether the first signal change slope is good; and making the current target satellite a satellite to be blocked if the first signal change slope deteriorates. . Detecting a second signal change slope within a second observation time of the target satellite;
13. The computer software according to claim 12, further comprising the step of determining whether the current target satellite is a satellite to be blocked based on a determination result with respect to the second signal change slope.

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