Satellite positioning device, satellite positioning method, and program

Abstract

One purpose of the present disclosure is to continue to execute accurate satellite positioning even when signal screening occurs.　A satellite positioning device (10) according to the present disclosure has: a generation unit (11) which generates first accumulated information (100) by associating, for each unit of receipt time / date information, which expresses the receipt time and date at which a positioning signal is received, the receipt time / date information (T1, T2, T3...) with observation information (pseudo-distance information, carrier phase information) which respectively corresponds to a positioning satellite (30) [30a, 30b, 30c, 30d, 30e] at the time / date of receipt, and stores the same in a storage device (20); and a correction unit (13) which refers to the first accumulated information (100) when there is an abnormality in the observation information at the current point in time (t0), generates corrected observation information for correcting the observation information at the current point in time (t0) at which there is an abnormality on the basis of past observation information which was stored before the current point in time (t0) and is obtained from the positioning satellite which corresponds to the observation information at the current point in time (t0) at which there is an abnormality, and corrects the observation information at the current point in time (t0) at which there is an abnormality in the first accumulated information (100) to the corrected observation information.

Description

Satellite positioning device, satellite positioning method, and computer-readable recording medium

[0001] The present disclosure relates to a satellite positioning device and a satellite positioning method for performing satellite positioning, and further to a computer-readable recording medium on which a program for realizing these is recorded.

[0002] In order to perform satellite positioning accurately, error factors such as (1) orbital error of the positioning satellite (artificial satellite), (2) clock error of the positioning satellite, (3) delay due to the ionosphere, (4) delay due to the troposphere, (5) signal shielding, and (6) multipath must be taken into consideration.

[0003] In particular, in urban areas with many high-rise buildings and mountainous areas with thick trees, the error factors (5) and (6) mentioned above have a large effect, making highly accurate satellite positioning difficult.

[0004] As a related technique, Patent Literature 1 discloses a position measurement device capable of continuously acquiring position information with high accuracy. The position measurement device performs a first position identification process that performs satellite positioning to acquire a current position and its error range, and a second position identification process that acquires the current position using measured values ​​of physical quantities, corrects the correspondence between the current position and the physical quantities obtained in the second position identification process if the error range satisfies a predetermined accuracy condition, and acquires the corrected result of the second position identification process when acquiring the current position.

[0005] The error range is calculated based on the positioning accuracy obtained by combining the reception conditions for each position of multiple positioning satellites and the deviation of the acquired current position from the predicted position according to the movement status of the aircraft.

[0006] Japanese Patent Application Laid-Open No. 2019-060619

[0007] However, in the position measurement device of Patent Document 1, satellite positioning can be realized when there are four or more visible satellites that can receive signals (radio waves) from positioning satellites, but satellite positioning cannot be realized when the number of visible satellites is three or less due to the effect of signal blocking described above (5).

[0008] An example of an object of the present disclosure is to continuously perform highly accurate satellite positioning even when signal blocking occurs.

[0009] In order to achieve the above object, a satellite positioning device according to one aspect of the present disclosure is characterized by having a receiving unit that receives positioning signals transmitted from each positioning satellite; a generating unit that generates first accumulated information by associating, for each reception date and time information indicating the reception date and time at which the positioning signal was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and stores the information in a storage device; and a correcting unit that, when there is an abnormality in the current observation information, refers to the first accumulated information, and generates corrected observation information for correcting the current observation information having an abnormality based on past observation information stored before the present time of the positioning satellite corresponding to the current observation information having an abnormality, and corrects the current observation information having an abnormality in the first accumulated information to the corrected observation information.

[0010] In addition, in order to achieve the above-mentioned object, a satellite positioning method in one aspect of the present disclosure is characterized in that it includes the steps of: a computer generating accumulated information by associating, for each reception date and time information indicating the date and time at which a positioning signal transmitted from each positioning satellite was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and storing the information in a storage device; and a step of, if there is an abnormality in the current observation information, referring to the first accumulated information, generating corrected observation information for correcting the current observation information with an abnormality based on past observation information stored before the present time of the positioning satellite corresponding to the current observation information with an abnormality, and correcting the current observation information with an abnormality in the first accumulated information to the corrected observation information.

[0011] Furthermore, in order to achieve the above-mentioned object, a computer-readable recording medium having a program recorded thereon according to one aspect of the present disclosure is characterized in that it records a program including instructions to execute the following steps: for each reception date and time information indicating the date and time at which a positioning signal transmitted from each positioning satellite was received, generate accumulated information by associating the reception date and time information with observation information corresponding to each positioning satellite at the reception date and time, and store the information in a storage device; and if there is an abnormality in the current observation information, refer to the first accumulated information and generate corrected observation information to correct the current observation information having an abnormality based on past observation information stored before the present time of the positioning satellite corresponding to the current observation information having an abnormality, and correct the current observation information having an abnormality in the first accumulated information to the corrected observation information.

[0012] As described above, according to the present disclosure, even if signal blocking occurs, it is possible to continuously perform highly accurate satellite positioning.

[0013] FIG. 1 is a diagram illustrating an example of a satellite positioning device included in a satellite positioning system. FIG. 2 is a diagram illustrating an example of the data structure of accumulated information (for observation information). FIG. 3 is a diagram illustrating signal blocking. FIG. 4 is a diagram illustrating a method for correcting observation information containing an abnormality. FIG. 5 is a diagram illustrating a method for correcting observation information containing an abnormality. FIG. 6 is a diagram illustrating bias in the arrangement of positioning satellites. FIG. 7 is a diagram illustrating accumulated information when the arrangement of positioning satellites is biased. FIG. 8 is a diagram illustrating an example of the data structure of accumulated information (for satellite position information). FIG. 9 is a diagram illustrating an example of the operation of the satellite positioning device. FIG. 10 is a diagram illustrating an example of a computer that realizes the satellite positioning device in an embodiment.

[0014] First, an overview will be provided to facilitate understanding of the embodiments described below. A satellite positioning device (user segment) is a device that measures its current position using multiple positioning satellites (space segments). The satellite positioning device is mounted on, for example, a vehicle, an aircraft, a ship, a mobile device, etc.

[0015] In the current satellite positioning system, if there are four or more visible satellites, the satellite positioning device can perform accurate satellite positioning (normal).

[0016] However, due to the influence of signal obstruction (5) mentioned above, the number of visible satellites decreases, and satellite positioning becomes impossible when the number of visible satellites falls to three or less. For example, in urban areas or mountainous regions, if radio waves are blocked by obstructions (e.g., buildings, trees, etc.) and the number of visible satellites falls to three or less, satellite positioning becomes impossible.

[0017] Furthermore, even if there are four or more visible satellites, if the observation information (observation data) described below contains abnormalities due to the influence of multipath described above (6), the accuracy of satellite positioning calculated using the observation information will decrease.

[0018] Furthermore, (7) even if the number of visible satellites is four or more, in urban areas, the visible satellites for satellite positioning are concentrated near the zenith, resulting in a bias in the placement of positioning satellites in the sky, which reduces the accuracy of satellite positioning.

[0019] Through this process, the inventor discovered the problem that accurate satellite positioning is not possible when (5) signal blocking occurs, or (6) multipath occurs, or (7) bias occurs in the placement of positioning satellites, and also came up with a means to solve the problem.

[0020] That is, the inventor has come up with a means for continuously performing highly accurate satellite positioning even when (5) signal blocking occurs, or (6) multipath occurs, or (7) bias occurs in the positioning satellite arrangement.

[0021] Hereinafter, embodiments will be described with reference to the drawings. In the drawings described below, elements having the same or corresponding functions are denoted by the same reference numerals, and repeated description thereof may be omitted.

[0022] (Embodiment) The configurations of a satellite positioning system and a satellite positioning device in an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram for explaining an example of a satellite positioning device included in a satellite positioning system.

[0023] 1 includes positioning satellites 30 (30a, 30b, 30c, 30d, and 30e) and a satellite positioning device 10. The number of positioning satellites 30 is not limited to five.

[0024] The satellite positioning system may be, for example, a Global Navigation Satellite System (GNSS), etc. Specifically, the satellite positioning system calculates the current position of the satellite positioning device 10 based on positioning signals transmitted from each of the positioning satellites 30.

[0025] The satellite positioning device 10 receives positioning signals from the positioning satellites 30 and generates observation information based on the received positioning signals. Thereafter, the satellite positioning device 10 calculates the current position based on the generated observation information.

[0026] The satellite positioning device 10 provides information indicating the calculated current position to various applications, such as a navigation system and an automatic driving system.

[0027] The satellite positioning device 10 is, for example, an information processing device such as a CPU (Central Processing Unit), a programmable device such as an FPGA (Field-Programmable Gate Array), a GPU (Graphics Processing Unit), or a circuit, computer, mobile terminal, or the like equipped with one or more of these.

[0028] The storage device 20 is a database, a server computer, a circuit having a memory, etc. The storage device 20 stores, for example, at least accumulated information, which will be described later. In the example of Fig. 1, the storage device 20 is provided outside the satellite positioning device 10, but it may also be provided inside the satellite positioning device 10.

[0029] The positioning satellite 30 orbits a predetermined satellite orbit at a predetermined orbital period, and transmits a positioning signal in which data indicating the transmission date and time, etc., is phase-modulated.

[0030] [Device Configuration] A detailed description will be given of the satellite positioning device 10. In the example of Fig. 1, the satellite positioning device 10 includes a receiving unit 11, a generating unit 12, a correcting unit 13, and an estimating unit 14.

[0031] In satellite positioning, the satellite positioning device 10 calculates the current position using observation information (pseudo-distance information, carrier wave phase information) and positioning satellite position information.

[0032] Positioning methods that require the positions of positioning satellites include, for example, point positioning, realtime kinematic (RTK) positioning, and precise point positioning (PPP) positioning.

[0033] The receiver 11 receives the positioning signals transmitted from each positioning satellite and generates observation information (pseudo-distance information, carrier phase information) and positioning satellite position information based on the received positioning signals. Specifically, the positioning signal receiver 21 has an antenna 11 a that receives the positioning signals, a circuit for demodulating the positioning signals, etc.

[0034] A case where there is an abnormality in the observation information (pseudo-distance information, carrier phase information) will be described. For each piece of reception date and time information indicating the date and time at which the positioning signal was received, the generation unit 12 generates accumulated information (first accumulated information) by associating the reception date and time information with the observation information corresponding to each positioning satellite at the reception date and time, and stores the information in the storage device 20.

[0035] The reception date and time information is information that indicates, for example, the year, month, date, and time when the positioning signal was received. The observation information includes pseudo-distance information that indicates the pseudo-distance, or carrier phase information that indicates the carrier phase, or both.

[0036] 2 is a diagram for explaining an example of the data structure of accumulated information (for observation information). In FIG. 2, accumulated information 101 and 102 are shown as an example of accumulated information 100 (first accumulated information).

[0037] The accumulated information 101 is information in which pseudorange information corresponding to each of the positioning satellites 30a, 30b, 30c, 30d, and 30e is associated with each of the times T1, T2, T3, etc. indicated by the reception date and time information. In the example of Fig. 2, for convenience of explanation, the pseudorange information is represented by symbols such as La11 to La13, etc., Lb11 to Lb13, etc., Lc11 to Lc13, etc., Ld11 to Ld13, etc., Le11 to Le13, etc.

[0038] Furthermore, the accumulated information 102 is information in which carrier phase information corresponding to each of the positioning satellites 30a, 30b, 30c, 30d, and 30e is associated with each of the times T1, T2, T3, etc. indicated by the reception date and time information. In the example of Fig. 2, for convenience of explanation, the carrier phase information is represented by symbols such as Pa11 to Pa13, etc., Pb11 to Pb13, etc., Pc11 to Pc13, etc., Pd11 to Pd13, etc., Pe11 to Pe13, etc.

[0039] If there is an abnormality in the observation information at the current time, the corrector 13 refers to the accumulated information 100 and generates corrected observation information for correcting the current observation information with an abnormality based on past observation information stored before the current time of the positioning satellite 30 corresponding to the observation information with an abnormality at the current time.The corrector 13 then corrects (changes) the current observation information with an abnormality in the accumulated information 100 to the corrected observation information.

[0040] Abnormalities in the observation information occur, for example, when (5) signal blocking occurs, or (6) multipath occurs, or (7) there is a bias in the positioning satellite arrangement.

[0041] (5) A case where signal blocking occurs will be described. When signal blocking occurs, the positioning signal cannot be received, and therefore, observation information (pseudo-range information, or carrier phase information, or both) cannot be obtained.

[0042] If the corrector 13 is unable to acquire the current observation information, it determines that the current observation information is abnormal. This will be described in detail with reference to FIGS.

[0043] Fig. 3 is a diagram for explaining signal blocking. In the example of Fig. 3, a vehicle 40 (mobile body) equipped with a satellite positioning device 10 is moving. The satellite positioning device 10 of the vehicle 40 receives positioning signals from four positioning satellites 30a, 30b, 30c, and 30d at times T1 and T2 (normal).

[0044] In contrast, at time T3, the positioning signal from the positioning satellite 30d is blocked by the building 50, and the satellite positioning device 10 of the vehicle 40 cannot receive the positioning signal from the positioning satellite 30d (abnormal). However, even at time T3, the satellite positioning device 10 of the vehicle 40 can receive the positioning signals from each of the three positioning satellites 30a, 30b, and 30c.

[0045] 4 is a diagram illustrating a method for correcting abnormal observation information. In the example of FIG. 4, the pseudoranges of the L1 signal band are expressed as simple numerical values ​​for ease of understanding. In the case of dual-frequency positioning, accumulated information for two signal bands is generated, and pseudorange information for both frequencies is used.

[0046] The accumulated information 101a shown in FIG. 4A indicates that the pseudorange information of the positioning satellite 30d could not be acquired at time T3 due to the influence of signal blocking (anomalous pseudorange information "-").

[0047] If the pseudorange information cannot be acquired, the modifying unit 13 modifies the anomalous pseudorange information. That is, if the observation information has an abnormality, the modifying unit 13 generates modified observation information to modify the anomalous observation information. Then, the modifying unit 13 modifies (changes) the anomalous observation information to the modified observation information.

[0048] The corrected observation information can be calculated, for example, by any one of the following methods (A), (B), (C), and (D).

[0049] In method (A), observation information from the positioning satellite corresponding to the observation information containing an abnormality is obtained from the time point one point (t1) before the current time point (t0) and the time point two points (t2) before that, and corrected observation information is generated based on equation 1.

[0050] (Equation 1) f1(t0) = f(t1) + (f(t1) - f(t2)) f1(t0): Corrected observation information f(t1): Observation information at the time (t1) one point before the current time (t0) f(t2): Observation information at the time (t2) two points before the current time (t0)

[0051] In the example of Figure 4, corrected observation information "7" is generated based on pseudorange information "6" and "5" for time points T1 (corresponding to t1) and T2 (corresponding to t2) stored before time point T3 (corresponding to t0) for positioning satellite 30d in accumulated information 101a.

[0052] Then, as shown in accumulated information 101b in FIG. 4B, the abnormal pseudo-range information "-" is corrected (changed) to corrected observation information "7" (corrected pseudo-range information).

[0053] In method (B), observation information from two past points (observation information from the point (t1) one point before the current point (t0) and the point (t2) two points before that) is obtained, a linear function (Equation 2) is generated, and corrected observation information is generated using the generated linear function.

[0054] (Equation 2) f2(t0) = a × t0 + b f2(t0): corrected observation information a: slope (f(t2) - f(t1) / t2 - t1) b: intercept

[0055] In method (C), observation information from three past points (observation information from the point in time (t1) one point in time before the current point in time (t0), the point in time two points in time before that (t2), and the point in time three points in time before that (t3)) is obtained, a quadratic function (Equation 3) is generated, and corrected observation information is generated using the generated quadratic function.

[0056] (Math. 3) f3(t0)=a×t0 ２ +b × t0 +c f3(t0): Corrected observation information a: Real-valued constant (≠0) b: Real-valued constant c: Real-valued constant

[0057] In method (D), corrected observation information is generated by the least squares method using observation information from a plurality of past points (observation information from one or more points prior to the current point in time (t0)).

[0058] In addition, as with the accumulated information for pseudo-distance information described above, if there is an abnormality in the accumulated information for carrier phase information, corrected observation information (corrected carrier phase information) is generated and the carrier phase information with the abnormality is corrected (changed) to the corrected observation information.

[0059] Furthermore, in the example of the stored information 101b in FIG. 4, observation information containing an abnormality is overwritten with corrected observation information, but overwriting is not necessary.

[0060] Furthermore, the uncorrected accumulated information and the corrected accumulated information may be stored separately in the storage device 20. Specifically, the uncorrected accumulated information 101a and the corrected accumulated information 101b in FIG. 4 may be stored separately in the storage device 20.

[0061] (6) When multipath occurs: When multipath occurs, the observed information (pseudorange information, or carrier phase information, or both) becomes an abnormal value (outlier).

[0062] The corrector 13 determines that the current observation information is abnormal if the change in the current observation information from the past observation information is equal to or greater than a preset threshold value. This will be described in detail with reference to FIG.

[0063] The threshold may be determined based on, for example, past observation information affected by multipath, or may be determined by experiments, simulations, etc. Thresholds are prepared for pseudorange information and carrier phase information, respectively.

[0064] Fig. 5 is a diagram for explaining a method for correcting abnormal observation information. In the example of Fig. 5, for ease of explanation, the pseudoranges of the L1 signal band are expressed by simple numerical values. In the case of dual-frequency positioning, accumulated information for two signal bands is generated, and pseudorange information for both frequencies is used.

[0065] The accumulated information 101c shown in FIG. 5A indicates that the pseudorange information of the positioning satellite 30a has become an abnormal value at time T5 due to the influence of multipath (abnormal pseudorange information "12").

[0066] 5, the threshold is set to 4 or more. Therefore, the current pseudorange information has changed by 4 or more from the pseudorange information at the immediately previous time point, and therefore the current pseudorange information is an abnormal value.

[0067] If the pseudorange information is an abnormal value, the corrector 13 corrects the abnormal pseudorange information. That is, if the observation information is abnormal, the corrector 13 generates corrected observation information in order to correct the abnormal observation information.

[0068] The corrected observation information can be calculated, for example, by any one of the above-mentioned methods (A), (B), (C), and (D).

[0069] In the example of Figure 5, method (A) is used to generate corrected observation information "6" based on pseudorange information "7" and "8" for time points T1 (corresponding to t1) and T2 (corresponding to t2) of positioning satellite 30a stored in accumulated information 101c before time point T5 (corresponding to t0).

[0070] Then, as shown in accumulated information 101d in FIG. 5B, the abnormal pseudo-range information "12" is corrected (changed) to corrected observation information "6" (corrected pseudo-range information).

[0071] Furthermore, in the example of the stored information 101d in FIG. 5, observation information containing an abnormality is overwritten with corrected observation information, but overwriting is not necessary.

[0072] Furthermore, the uncorrected accumulated information and the corrected accumulated information may be stored separately in the storage device 20. Specifically, the uncorrected accumulated information 101c and the corrected accumulated information 101d in FIG. 5 may be stored separately in the storage device 20.

[0073] (7) A case where a bias occurs in the arrangement of positioning satellites will be described. Fig. 6 is a diagram for explaining the bias in the arrangement of positioning satellites. (5) There is a positioning satellite 30d from which positioning signals cannot be received due to the influence of signal blocking, but there is another visible satellite 30e (positioning satellite) from which positioning signals can be received.

[0074] However, blocking the signal from positioning satellite 30d, which is the only one in a different direction, causes a bias in the arrangement of satellites available for positioning, reducing the accuracy of satellite positioning. For example, suppose that positioning satellite 30a is in the northeast, positioning satellite 30b is in the east, positioning satellite 30c is in the southeast, positioning satellite 30d is in the west, and positioning satellite 30e is in the east. In this case, if only positioning satellite 30d is blocked, there will be no positioning satellites located in the west, and the positioning satellites will be biased to the east, reducing the accuracy of satellite positioning.

[0075] Therefore, even if the correction unit 13 is able to switch to another visible satellite 30e, it generates corrected observation information for the positioning satellite 30d using one of the methods (A), (B), (C), or (D) described above for a predetermined period of time.

[0076] The predetermined period is a period in which the accuracy of satellite positioning does not decrease, and may be determined, for example, through experiments, simulations, or the like.

[0077] 7 is a diagram illustrating the accumulated information when the positioning satellites are unevenly positioned. In the accumulated information 101e in FIG. 7, at times T5 and T6, observation information (pseudo-distance information) of the positioning satellite 30c can no longer be acquired, but the positioning signal of the visible satellite 30e can still be received.

[0078] However, in the stored information 101f of Fig. 7, the observation information (pseudo-range information) of the visible satellite 30e is not used, and the corrected observation information "5" and "5" of the positioning satellite 30d is still used. Note that the example of Fig. 7 shows that at time T7 (within the period), normal observation information of the positioning satellite 30d became available.

[0079] In an embodiment, even if there is an abnormality in the observation information at the current time, that is, (5) if signal blocking occurs, or (6) if there is a multipath effect, or (7) if there is a bias in the positioning satellite arrangement, the abnormal observation information can be corrected based on past observation information stored before the current time, thereby enabling continuous, accurate satellite positioning.

[0080] A case where there is an abnormality in the positioning satellite position information will be described. The generation unit 12 generates accumulated information (second accumulated information) by associating the positioning satellite position information with each piece of reception date and time information, and stores the information in the storage device 20.

[0081] If there is an abnormality in the current positioning satellite position information, the correction unit 13 first refers to the accumulated information (second accumulated information) and generates corrected positioning satellite position information for correcting the current positioning satellite position information where there is an abnormality, based on past positioning satellite position information stored before the current time for the positioning satellite 30 corresponding to the current positioning satellite position information where there is an abnormality.

[0082] Next, the correction unit 13 corrects the current positioning satellite position information at which the abnormality exists in the stored information (second stored information) to corrected positioning satellite position information.

[0083] 8 is a diagram illustrating an example of the data structure of accumulated information (for satellite position information). Accumulated information 201a shown in A of Fig. 8 is information in which satellite position information corresponding to each of positioning satellites 30a, 30b, 30c, 30d, and 30e is associated with each of time points T1, T2, T3, ... represented by reception date and time information. The satellite position information is information expressed in three-dimensional coordinates.

[0084] In the accumulated information 201a shown in A of Figure 8, due to the effects of (5), (6), and (7) described above, there were abnormalities in the observation information at time T5 for positioning satellite 30a, time T6 and T7 for positioning satellite 30c, and time T8 and T9 for positioning satellite 30e, and therefore abnormalities occurred in the satellite position information.

[0085] That is, the accumulated information 201a shown in A of Figure 8 indicates that an abnormality occurred in the satellite position information "30, 10, 42" for positioning satellite 30a at time T5, an abnormality occurred in the satellite position information "-" for positioning satellite 30c at time T6 and T7, and an abnormality occurred in the satellite position information "-" for positioning satellite 30e at time T7, T8, and T9.

[0086] Therefore, if there is an abnormality in the satellite position information, the correction unit 13 corrects the abnormal satellite position information. Specifically, if there is an abnormality in the satellite position information, the correction unit 13 generates corrected satellite position information (X', Y', Z') for correcting each of the three-dimensional coordinates (X, Y, Z) of the abnormal satellite position information.

[0087] The satellite position information is determined to be abnormal if (5) the satellite position information cannot be obtained due to the influence of signal obstruction, or (6) the change in the current satellite position information compared to the past satellite position information due to the influence of multipath is greater than or equal to a predetermined threshold.

[0088] The threshold value may be determined based on, for example, satellite position information that has been affected by past multipath events, or may be determined through experiments, simulations, or the like.

[0089] Each of the three-dimensional coordinates of the corrected satellite position information can be calculated by, for example, one of the following methods (A'), (B'), (C'), and (D').

[0090] In method (A'), satellite position information for the positioning satellite corresponding to the abnormal satellite position information is obtained at the time point (t1) one point before the current time point (t0) and the time point two points before that (t2), and corrected satellite position information (three-dimensional coordinates (X', Y', Z') respectively) is generated based on equation 1'.

[0091] (Equation 1') g1(t0) = g(t1) + (g(t1) - g(t2)) g1(t0): Corrected satellite position information (three-dimensional coordinates) g(t1): Satellite position information at the time (t1) one point before the current time (t0) g(t2): Satellite position information at the time (t2) two points before the current time (t0)

[0092] At time T5 of the positioning satellite 30a in the accumulated information 201a shown in A of Figure 8, corrected satellite position information "11, 36, 13" is generated based on the satellite position information "11, 35, 13" and "11, 34, 13" for times T4 (corresponding to t1) and T3 (corresponding to t2) stored before time T5 (corresponding to t0) of the positioning satellite 30a.

[0093] Then, as shown in accumulated information 201b in FIG. 8B, the abnormal satellite position information "30, 10, 42" is corrected (changed) to corrected satellite position information "11, 36, 13."

[0094] Furthermore, for the abnormal satellite position information "-" for positioning satellite 30c at time points T6 and T7, method (A') is used to generate corrected satellite position information "30, 32, 15" and "30, 34, 15." For the abnormal satellite position information "-" for positioning satellite 30e at time points T7, T8, and T9, method (A') is used to generate corrected satellite position information "38, 60, 40," "36, 60, 40," and "34, 60, 40."

[0095] In method (B'), satellite position information for two past points (satellite position information for the point in time (t1) one point before the current point in time (t0) and the point in time two points before that (t2)) is obtained, a linear function (Equation 2') is generated, and corrected satellite position information (three-dimensional coordinates) is generated using the generated linear function.

[0096] (Equation 2') g2(t0) = a × t0 + b g2(t0): corrected satellite position information (three-dimensional coordinates) a: gradient (g(t2) - g(t1) / t2 - t1) b: intercept

[0097] In method (C'), satellite position information for three past points (satellite position information for the point in time (t1) one point in time before the current point in time (t0), the point in time two points in time before that (t2), and the point in time three points in time before that (t3)) is obtained, a quadratic function (Equation 3') is generated, and corrected satellite position information is generated using the generated quadratic function.

[0098] (Equation 3') g3(t0) = a × t0 ２ +b×t0+c g3(t0): Corrected satellite position information (three-dimensional coordinates) a: Real-valued constant (≠0) b: Real-valued constant c: Real-valued constant

[0099] In the method (D'), corrected satellite position information is generated by the least squares method using satellite position information from a plurality of past points (satellite position information from one or more points prior to the current point in time (t0)).

[0100] The estimation unit 14 executes satellite positioning processing to calculate the current position using the observation information and satellite position information of each positioning satellite included in the currently stored information, and estimates the current position.

[0101] Furthermore, in the example of the stored information 201b in FIG. 8, the satellite position information having an abnormality is overwritten with the corrected satellite position information, but this overwriting is not necessary.

[0102] Furthermore, the uncorrected accumulated information and the corrected accumulated information may be stored separately in the storage device 20. Specifically, the uncorrected accumulated information 201a and the corrected accumulated information 201b in FIG. 8 may be stored separately in the storage device 20.

[0103] The estimation unit 14 executes a satellite positioning process to calculate the current position using the observation information of each positioning satellite 30 and the positioning satellite position information at the current time, and estimates the current position.

[0104] In the embodiment, even if there is an abnormality in the satellite position information at the current time, that is, (5) if signal blocking occurs, or (6) if there is an effect of multipath, or (7) if there is a bias in the positioning satellite arrangement, the abnormal satellite position information is corrected based on past satellite position information stored before the current time, thereby enabling continuous, highly accurate satellite positioning.

[0105] In addition, even in an open sky environment, if a visible satellite moves into a range of an elevation angle of 0 degrees or less and becomes an invisible satellite, satellite positioning processing is performed for a preset period using correction information for the invisible satellite.

[0106] [Device Operation] Next, the operation of the satellite positioning device in the embodiment will be described with reference to FIG. 9. FIG. 9 is a diagram for explaining an example of the operation of the satellite positioning device. In the following description, the diagram will be referenced as appropriate. Furthermore, in the embodiment, a satellite positioning method is implemented by operating the satellite positioning device. Therefore, the description of the satellite positioning method in the embodiment will be replaced by the following description of the operation of the satellite positioning device.

[0107] As shown in Figure 9, first, the receiver 11 receives the positioning signals transmitted from each of the positioning satellites 30, and generates observation information (pseudo-distance information, carrier phase information) and positioning satellite position information based on the received positioning signals (step A1).

[0108] Next, for each piece of reception date and time information indicating the date and time at which the positioning signal was received, the generation unit 12 generates accumulated information (first accumulated information) by associating the reception date and time information with observation information (pseudo-distance information, carrier phase information) corresponding to each positioning satellite at the reception date and time, and stores the information in the storage device 20 (step A2).

[0109] In step A2, accumulated information (second accumulated information) is generated for each piece of reception date and time information in association with positioning satellite position information indicating the position of each positioning satellite, and is stored in the storage device 20.

[0110] Next, if there is no abnormality in the observation information and the positioning satellite position information at the current time (step A3: No), the corrector 13 proceeds to step A5 and executes the satellite positioning process. Also, if there is an abnormality in the pseudorange information, the carrier phase information, the positioning satellite position information, or any two or more of the information at the current time (step A3: Yes), the corrector 13 proceeds to step A4 and generates corrected observation information and corrected positioning satellite position information for the information with the abnormality.

[0111] In step A3, the correction unit 13 determines that an abnormality has occurred if (5) signal blocking occurs and current pseudorange information, carrier phase information, or positioning satellite position information cannot be acquired.

[0112] In step A3, the correction unit 13 determines that the current observation information is abnormal if the change in the current observation information relative to the past observation information is equal to or greater than a preset threshold value when multipath occurs. The abnormality in the pseudorange information is determined using the change in the pseudorange information and a threshold value for the pseudorange information. The abnormality in the carrier phase information is determined using the change in the carrier phase information and a threshold value for the carrier phase information.

[0113] Also, in step A3, (6) when multipath occurs, if the change in the current positioning satellite position information relative to the past positioning satellite position information is equal to or greater than a predetermined threshold (threshold for positioning satellite position information), the correction unit 13 determines that the current positioning satellite position information is abnormal.

[0114] Next, if there is an abnormality in the observation information (pseudorange information, or carrier phase information, or both) at the current time, the correction unit 13 refers to the first accumulated information and generates corrected observation information to correct the abnormal observation information based on past observation information stored before the current time of the positioning satellite 30 corresponding to the observation information that is abnormal at the current time (step A4).

[0115] Specifically, in step A4, the corrector 13 generates corrected observation information by any one of the above-mentioned methods (A), (B), (C), and (D). Then, in step A4, the corrector 13 corrects (changes) the observation information containing an anomaly to the corrected observation information.

[0116] Also, in step A4, if there is an abnormality in the positioning satellite position information at the current time, the correction unit 13 refers to the second accumulated information and generates corrected positioning satellite position information for correcting the abnormal positioning satellite position information based on past positioning satellite position information stored before the current time for the positioning satellite 30 corresponding to the abnormal positioning satellite position information at the current time.

[0117] Specifically, in step A4, the correction unit 13 generates corrected positioning satellite position information by any one of the above-mentioned methods (A'), (B'), (C'), and (D'). Then, in step A4, the correction unit 13 corrects (changes) the positioning satellite position information having the abnormality to the corrected positioning satellite position information.

[0118] The estimation unit 14 performs satellite positioning processing to calculate the current position using the observation information of each positioning satellite and the positioning satellite position information contained in the current accumulated information (first accumulated information, second accumulated information), and estimates the current position (step A5).

[0119] In this way, the satellite positioning device 10 repeatedly executes the processes of steps A1 to A5 described above.

[0120] [Effects of the embodiment] According to the embodiment, even if there is an abnormality in the observation information at the current time, that is, (5) if signal blocking occurs, or (6) if there is an effect of multipath, or (7) if there is a bias in the positioning satellite arrangement, the observation information with the abnormality is corrected based on past observation information stored before the current time, thereby enabling continuous, highly accurate satellite positioning.

[0121] [Program] The program in the embodiment may be a program that causes a computer to execute steps A1 to A5 shown in Fig. 9. By installing and executing this program on a computer, the satellite positioning device and satellite positioning method in the embodiment can be realized. In this case, the processor of the computer functions as a receiving unit 11, a generating unit 12, a correcting unit 13, and an estimating unit 14 and performs processing.

[0122] The program in the embodiment may be executed by a computer system constructed by a plurality of computers, in which case, for example, each computer may function as one of the receiving unit 11, the generating unit 12, the correcting unit 13, and the estimating unit 14.

[0123] [Physical Configuration] A computer that implements the satellite positioning device by executing a program in the embodiment will now be described with reference to Fig. 10. Fig. 10 is a diagram illustrating an example of a computer that implements the satellite positioning device in the embodiment.

[0124] 10 , the computer 110 includes a CPU (Central Processing Unit) 111, a main memory 112, a storage device 113, an input interface 114, a display controller 115, a data reader / writer 116, and a communication interface 117. These components are connected to each other via a bus 121 so as to be able to communicate data with each other. Note that the computer 110 may include a GPU or an FPGA in addition to or instead of the CPU 111.

[0125] The CPU 111 loads the programs (codes) in the embodiment stored in the storage device 113 into the main memory 112 and executes them in a predetermined order to perform various calculations. The main memory 112 is typically a volatile storage device such as a dynamic random access memory (DRAM). The programs in the embodiment are provided in a state stored in a computer-readable recording medium 120. The programs in the embodiment may be distributed over the Internet connected via the communication interface 117. The recording medium 120 is a non-volatile recording medium.

[0126] Specific examples of the storage device 113 include a hard disk drive and a semiconductor storage device such as a flash memory. The input interface 114 mediates data transmission between the CPU 111 and input devices 118 such as a keyboard and a mouse. The display controller 115 is connected to a display device 119 and controls the display on the display device 119.

[0127] The data reader / writer 116 mediates data transmission between the CPU 111 and the recording medium 120, reads programs from the recording medium 120, and writes processing results from the computer 110 to the recording medium 120. The communication interface 117 mediates data transmission between the CPU 111 and other computers.

[0128] Specific examples of the recording medium 120 include general-purpose semiconductor storage devices such as CF (Compact Flash (registered trademark)) and SD (Secure Digital), magnetic recording media such as flexible disks, or optical recording media such as CD-ROMs (Compact Disk Read Only Memory).

[0129] The satellite positioning device in the embodiment can be realized by using hardware corresponding to each part, rather than a computer on which a program is installed. Furthermore, the satellite positioning device 10 may be realized in part by a program and in the remaining part by hardware.

[0130] Although the present invention has been described above with reference to the embodiments, it is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details within the scope of the invention.

[0131] [Supplementary Note] The following supplementary note is further disclosed regarding the above-described embodiment. Some or all of the above-described embodiment can be expressed by (Supplementary Note 1) to (Supplementary Note 21) described below, but is not limited to the following description.

[0132] (Supplementary Note 1) A satellite positioning device comprising: a receiving unit that receives positioning signals transmitted from each positioning satellite; a generating unit that generates first accumulated information by associating, for each piece of reception date and time information indicating the reception date and time at which the positioning signal was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and stores the first accumulated information in a storage device; and a correcting unit that, if there is an abnormality in the current observation information, references the first accumulated information and generates corrected observation information for correcting the current observation information with an abnormality based on past observation information stored before the present time of the positioning satellite that corresponds to the current observation information with an abnormality, and corrects the current observation information with an abnormality in the first accumulated information to the corrected observation information.

[0133] (Supplementary Note 2) The satellite positioning device described in Supplementary Note 1, wherein the correction unit determines that the current observation information is abnormal if the current observation information cannot be obtained or if a change in the current observation information relative to the past observation information is equal to or greater than a preset threshold.

[0134] (Supplementary Note 3) The satellite positioning device according to Supplementary Note 2, wherein the observation information includes pseudo-range information representing a pseudo-range, or carrier phase information representing a carrier phase, or both of these pieces of information.

[0135] (Supplementary Note 4) The satellite positioning device according to Supplementary Note 3, wherein when the pseudorange information is used, a stand-alone positioning process is executed as the satellite positioning process.

[0136] (Supplementary Note 5) The satellite positioning device according to Supplementary Note 3, wherein when the carrier wave phase information is used, a real-time kinematic positioning process is executed as the satellite positioning process.

[0137] (Supplementary Note 6) The satellite positioning device according to Supplementary Note 3, wherein when the pseudorange information and the carrier wave phase information are used, a precise point positioning process is executed as the satellite positioning process.

[0138] (Supplementary Note 7) The satellite positioning device according to Supplementary Note 1, wherein the generation unit generates second accumulated information by associating the positioning satellite position information with each of the reception date and time information when the positioning method requires positioning satellite position information indicating the position of the positioning satellite in the course of the satellite positioning process, and stores the second accumulated information in the storage device; the correction unit, when there is an abnormality in the current positioning satellite position information, refers to the second accumulated information, and generates corrected positioning satellite position information for correcting the current positioning satellite position information having an abnormality based on past positioning satellite position information stored before the present time of the positioning satellite corresponding to the current positioning satellite position information having an abnormality, and corrects the current positioning satellite position information having an abnormality in the second accumulated information to the corrected positioning satellite position information; and the estimation unit executes the satellite positioning process to calculate the current position using the observation information and positioning satellite position information of each of the positioning satellites at the present time, and estimates the current position.

[0139] (Supplementary Note 8) A satellite positioning method in which a computer generates first accumulated information by associating, for each reception date and time information indicating the reception date and time at which a positioning signal transmitted from each positioning satellite was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and stores the information in a storage device; if there is an abnormality in the current observation information, the computer refers to the first accumulated information and generates corrected observation information for correcting the current observation information with an abnormality based on past observation information stored before the present time of the positioning satellite corresponding to the current observation information with an abnormality, and corrects the current observation information with an abnormality in the first accumulated information to the corrected observation information.

[0140] (Supplementary Note 9) The satellite positioning method according to Supplementary Note 8, wherein the current observation information is determined to be abnormal if the current observation information cannot be obtained or if the change in the current observation information relative to the past observation information is equal to or greater than a preset threshold.

[0141] (Supplementary Note 10) The satellite positioning method according to Supplementary Note 9, wherein the observation information includes pseudo-range information indicating a pseudo-range, or carrier phase information indicating a carrier phase, or both of these pieces of information.

[0142] (Supplementary Note 11) The satellite positioning method according to Supplementary Note 10, wherein when the pseudorange information is used, a stand-alone positioning process is executed as the satellite positioning process.

[0143] (Supplementary Note 12) The satellite positioning method according to Supplementary Note 10, wherein when the carrier wave phase information is used, a real-time kinematic positioning process is executed as the satellite positioning process.

[0144] (Supplementary Note 13) The satellite positioning method according to Supplementary Note 10, wherein when the pseudorange information and the carrier wave phase information are used, a precise point positioning process is executed as the satellite positioning process.

[0145] (Supplementary Note 14) The satellite positioning method according to Supplementary Note 8, wherein, in the case where the positioning method requires positioning satellite position information indicating the position of the positioning satellite in the course of the satellite positioning process, second accumulated information is generated by associating the positioning satellite position information with each of the reception date and time information and the second accumulated information is stored in the storage device; if there is an abnormality in the current positioning satellite position information, the second accumulated information is referenced and corrected positioning satellite position information for correcting the current positioning satellite position information having an abnormality is generated based on past positioning satellite position information stored before the present time of the positioning satellite corresponding to the current positioning satellite position information having an abnormality, and the current positioning satellite position information having an abnormality in the second accumulated information is corrected to the corrected positioning satellite position information; and the satellite positioning process is performed to calculate the current position using the observation information and positioning satellite position information of each of the positioning satellites at the current time, thereby estimating the current position.

[0146] (Supplementary Note 15) A computer-readable recording medium having a program recorded thereon, including instructions for causing a computer to: for each reception date and time information indicating the reception date and time at which a positioning signal transmitted from each positioning satellite was received, generate first accumulated information by associating the reception date and time information with observation information corresponding to each positioning satellite at the reception date and time, and store the information in a storage device; if there is an abnormality in the current observation information, refer to the first accumulated information and generate corrected observation information to correct the current observation information having an abnormality based on past observation information stored before the present time of the positioning satellite corresponding to the current observation information having an abnormality, and correct the current observation information having an abnormality in the first accumulated information to the corrected observation information.

[0147] (Appendix 16) The computer-readable recording medium according to appendix 15, wherein the current observation information is judged to be abnormal if the current observation information cannot be obtained or if the change in the current observation information relative to the past observation information is equal to or greater than a preset threshold.

[0148] (Supplementary Note 17) The computer-readable recording medium according to Supplementary Note 16, wherein the observation information includes pseudo-range information representing a pseudo-range, or carrier phase information representing a carrier phase, or both of these pieces of information.

[0149] (Supplementary Note 18) The computer-readable recording medium according to Supplementary Note 17, wherein when the pseudorange information is used, a point positioning process is executed as a satellite positioning process.

[0150] (Supplementary Note 19) The computer-readable recording medium according to Supplementary Note 17, wherein when the carrier wave phase information is used, real-time kinematic positioning processing is executed as the satellite positioning processing.

[0151] (Supplementary Note 20) The computer-readable recording medium according to Supplementary Note 17, wherein when the pseudorange information and the carrier wave phase information are used, a precise point positioning process is executed as a satellite positioning process.

[0152] (Supplementary Note 21) When the positioning method requires positioning satellite position information indicating the position of the positioning satellite in the satellite positioning process, second accumulated information is generated by associating the positioning satellite position information with each of the reception date and time information and stored in the storage device; when there is an abnormality in the current positioning satellite position information, the second accumulated information is referenced and corrected positioning satellite position information for correcting the current positioning satellite position information having an abnormality is generated based on past positioning satellite position information stored before the present time of the positioning satellite corresponding to the current positioning satellite position information having an abnormality, and the current positioning satellite position information having an abnormality in the second accumulated information is corrected to the corrected positioning satellite position information; and the satellite positioning process is executed to calculate the current position using the observation information and positioning satellite position information of each of the positioning satellites at the current time, thereby estimating the current position.

[0153] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0154] This application claims priority based on Japanese Patent Application No. 2022-088159, filed on May 31, 2022, the disclosure of which is incorporated herein in its entirety by reference.

[0155] According to the above description, even when (5) signal blocking occurs, or (6) there is an effect of multipath, or (7) a bias occurs in the arrangement of positioning satellites, it is possible to continuously perform highly accurate satellite positioning. Also, this is useful in fields where highly accurate satellite positioning is required.

[0156] 10 Satellite positioning device 11 Receiving unit 11a Antenna 12 Generating unit 13 Correcting unit 14 Estimating unit 20 Storage device 30, 30a, 30b, 30c, 30d, 30e Positioning satellite 40 Vehicle 50 Building 110 Computer 111 CPU 112 Main memory 113 Storage device 114 Input interface 115 Display controller 116 Data reader / writer 117 Communication interface 118 Input device 119 Display device 120 Recording medium 121 Bus

Claims

1. A receiving means for receiving a positioning signal transmitted from each of the positioning satellites; a generating means for generating first accumulated information by associating, for each piece of reception date and time information indicating a reception date and time when the positioning signal was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and storing the first accumulated information in a storage device; a correction means for, when an abnormality exists in the current observation information, generating corrected observation information for correcting the current observation information having an abnormality based on past observation information stored before the present time of the positioning satellite corresponding to the current observation information having an abnormality by referring to the first accumulated information, and correcting the current observation information having an abnormality in the first accumulated information to the corrected observation information; A satellite positioning device having the above configuration.

2. The correction means determines that the current observation information is abnormal when the current observation information cannot be acquired or when a change in the current observation information from the past observation information is equal to or greater than a preset threshold value. The satellite positioning device according to claim 1 .

3. The observation information includes pseudo-range information representing a pseudo-range, or carrier phase information representing a carrier phase, or both of these. The satellite positioning device according to claim 2.

4. When the pseudorange information is used, a single point positioning process is executed as a satellite positioning process. The satellite positioning device according to claim 3.

5. When the carrier wave phase information is used, a real-time kinematic positioning process is executed as the satellite positioning process. The satellite positioning device according to claim 3.

6. When the pseudorange information and the carrier phase information are used, a precise point positioning process is executed as a satellite positioning process. The satellite positioning device according to claim 3.

7. the generating means, when a positioning method requires positioning satellite position information indicating the position of the positioning satellite in the satellite positioning process, generates second accumulated information by associating the positioning satellite position information with each of the reception date and time information, and stores the second accumulated information in the storage device; the correction means, when there is an abnormality in the current positioning satellite position information, refers to the second accumulated information, and generates corrected positioning satellite position information for correcting the current positioning satellite position information having an abnormality based on past positioning satellite position information stored before the present time of the positioning satellite corresponding to the current positioning satellite position information having an abnormality, and corrects the current positioning satellite position information having an abnormality in the second accumulated information to the corrected positioning satellite position information; The estimation means executes the satellite positioning process to calculate a current position using the observation information of each of the positioning satellites and the positioning satellite position information at the current time, and estimates the current position. The satellite positioning device according to claim 1 .

8. The computer generating first accumulated information by associating, for each piece of reception date and time information indicating a reception date and time at which a positioning signal transmitted from each of the positioning satellites was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and storing the first accumulated information in a storage device; When an abnormality is found in the current observation information, the first accumulated information is referred to, and corrected observation information for correcting the current observation information having an abnormality is generated based on past observation information stored before the current time of the positioning satellite corresponding to the current observation information having an abnormality, and the current observation information having an abnormality in the first accumulated information is corrected to the corrected observation information. Satellite positioning method.

9. If the current observation information cannot be obtained, or if a change in the current observation information from the past observation information is equal to or greater than a preset threshold, the current observation information is determined to be abnormal. The satellite positioning method according to claim 8.

10. The observation information includes pseudo-range information representing a pseudo-range, or carrier phase information representing a carrier phase, or both of these. The satellite positioning method according to claim 9.

11. When the pseudorange information is used, a single point positioning process is executed as a satellite positioning process. The satellite positioning method according to claim 10.

12. When the carrier wave phase information is used, a real-time kinematic positioning process is executed as the satellite positioning process. The satellite positioning method according to claim 10.

13. When the pseudorange information and the carrier phase information are used, a precise point positioning process is executed as a satellite positioning process. The satellite positioning method according to claim 10.

14. In the case where the positioning method requires positioning satellite position information indicating the position of the positioning satellite in the satellite positioning process, the positioning satellite position information is associated with each of the reception date and time information to generate second accumulated information, and the second accumulated information is stored in the storage device; When the current positioning satellite position information has an abnormality, the second accumulated information is referred to, and corrected positioning satellite position information for correcting the current positioning satellite position information having an abnormality is generated based on past positioning satellite position information stored before the current time of the positioning satellite corresponding to the current positioning satellite position information having an abnormality, and the current positioning satellite position information having an abnormality in the second accumulated information is corrected to the corrected positioning satellite position information; Execute the satellite positioning process to calculate the current position using the observation information of each of the positioning satellites and the positioning satellite position information at the current time, and estimate the current position. The satellite positioning method according to claim 8.

15. On the computer, generating first accumulated information by associating, for each piece of reception date and time information indicating a reception date and time at which a positioning signal transmitted from each of the positioning satellites was received, the reception date and time information with observation information corresponding to each of the positioning satellites at the reception date and time, and storing the first accumulated information in a storage device; When an abnormality is found in the current observation information, the first accumulated information is referred to, and corrected observation information for correcting the current observation information having an abnormality is generated based on past observation information stored before the current time of the positioning satellite corresponding to the current observation information having an abnormality, and the current observation information having an abnormality in the first accumulated information is corrected to the corrected observation information. A program containing instructions.