WO2019143006A1

WO2019143006A1 - Method and apparatus for estimating position on basis of position-domain hatch filter by using multiple gnss

Info

Publication number: WO2019143006A1
Application number: PCT/KR2018/013409
Authority: WO
Inventors: 김라우; 최광호; 이형근; 임준후; 유원재; 이유담
Original assignee: 한국항공대학교산학협력단
Priority date: 2018-01-17
Filing date: 2018-11-06
Publication date: 2019-07-25

Abstract

The present application relates to a method and an apparatus for estimating a position on the basis of a position-domain hatch filter by using multiple GNSS. The method for estimating a position comprises the steps of: (a) allowing a GNSS receiver to receive GNSS raw data from at least one visible satellite when the at least one visible satellite from among a plurality of GNSS satellites is present at a k^th time; and (b) allowing a position-domain hatch filter to perform time propagation, as a current position estimate at the k^thtime, a previous position estimate at a (k-1)^th time prior to the k^th time by using an indirect measurement for time propagation. The plurality of GNSS satellites include different types of satellites. The previous position estimate and the current position estimate include an estimated position of the GNSS receiver and an estimated clock error of the GNSS receiver for the plurality of GNSS satellites, wherein the indirect measurement for time propagation includes an actual measurement generated in consideration of the GNSS raw data and a virtual measurement generated in consideration of a clock error condition and a dynamic condition of the GNSS receiver.

Description

Location-based HATCH filter-based location estimation method and apparatus using multiple GNSS

The present invention relates to a location area Hatch filter-based location estimation method and apparatus using multiple GNSS.

Recently, autonomous navigation system is actively developed. Safety is one of the essential elements in an autonomous navigation system, and safety starts with accurate location information. Various studies based on the Global Navigation Satellite System (GNSS) have been carried out for precise location estimation.

However, in urban areas, frequent occurrence of difficulty in securing the GNSS satellite due to the influence of high-rise buildings and overpasses occurs frequently. Generally, when the number of GNSS visible satellites is insufficient, the position estimation is impossible or a large positioning error occurs.

In addition, in the study of existing urban location estimation, we tried to mitigate the shortage of visible satellite of GPS, which is a stand alone satellite navigation system, by combining various sensors such as INS, LiDAR and image sensor in GPS. However, the hardware that combines to mitigate visible satellite shortage of GPS is relatively expensive and the location estimation algorithm is also complex.

The background technology of this application is H.K. Lee and C. Rizos, "Position-domain Hatch filter for kinematic differential GPS / GNSS," IEEE Transactions on Aerospace and Electronic Systems, vol. 44 (1), January 2008.

The present invention solves the above-mentioned problems of the prior art, and it is an object of the present invention to provide GNSS availability by utilizing multiple GNSSs including different kinds of satellites (for example, GPS, GLONASS, and BeiDou) Area Hatch filter based position estimation method and apparatus using multiple GNSS that can greatly improve the performance of the present invention.

In order to solve the problems of the conventional techniques described above, the present invention provides a position-area Hatch filter-based position estimation method and apparatus using multiple GNSSs capable of precise and continuous positioning by designing a position-area Hatch filter combining a plurality of GNSSs .

In order to solve the problems of the conventional art described above, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide an apparatus and method for providing multiple visible GNSS using multiple GNSSs, And to provide a method and an apparatus for estimating a location area based on a utilized hatch filter.

It should be understood, however, that the technical scope of the embodiments of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

According to a first aspect of the present invention, there is provided a position-area Hatch filter-based position estimation method using multiple GNSSs, comprising the steps of: (a) (B) if the location-area Hatch filter is located at the (k-1) th time point, which is before the k-th point of time, using the indirect measurement for the tactical moon, Time propagation of the previous position estimate at the kth time point to the current position estimate at the kth time point, wherein the plurality of GNSS satellites comprise different types of satellites, Wherein the current position estimate includes an estimated position of the GNSS receiver and an estimated clock error of the GNSS receiver for the plurality of GNSS satellites, The indirect measurement for the tactic may include an actual measurement value generated in consideration of the GNSS source data and a virtual measurement value generated in consideration of the clock error condition and the dynamic condition condition of the GNSS receiver.

According to one embodiment of the present application, the clock error condition is based on the fact that the GNSS receiver is driven by a single oscillator, the clock error increment value of the GNSS receiver for each of the different kinds of satellites (K-1) th time point and the kth time point is an interval in seconds, the dynamic condition condition is a condition that the It may be a condition that the dynamic state of the GNSS receiver and the dynamic state of the GNSS receiver at the kth viewpoint are the same.

According to one embodiment of the present application, the actual measurements may be generated using increments of the carrier phase measurements for each of the different types of satellites obtained from the GNSS raw data.

According to an embodiment of the present invention, (c) the location area Hatch filter calculates the number of visible satellites at the kth viewpoint based on the acquired state of the GNSS raw data at the kth viewpoint, And (d) if the number of visible satellites is determined to be satisfied, updating the present position estimate at the k-th point of time using the indirect measurement for updating to generate an updated measurement value have.

According to one embodiment of the present application, the update measure may be generated using pseudorange measurements obtained via GNSS primitive data provided from the one or more visible satellites.

According to one embodiment of the present invention, the different kinds of satellites may include a GPS satellite, a GLONASS satellite, and a BeiDou satellite.

According to an embodiment of the present invention, in the step (a), the data processor identifies the GNSS primitive data as normal data or abnormal data using a Doppler comparison method among FDI (Fault Detection and Isolation) ) May be performed considering only normal data among the GNSS raw data.

According to an embodiment of the present invention, in the step (a), the data processing unit may calculate a difference between a Doppler measurement included in GNSS raw data provided from any one of the one or more visible satellites and an increment of a pseudorange The GNSS raw data provided from any one of the visible satellites can be identified as abnormal data when the difference between the Doppler measurement and the increment of the carrier phase measurement is larger than a predetermined second difference .

In addition, according to a second aspect of the present invention, there is provided a location-area-based Hatch-filter-based position estimating apparatus using multiple GNSSs, wherein when at least one of a plurality of GNSS satellites is present at a k- (K-1) th time point that is earlier than the kth time point by the present position estimate at the kth point, using the GNSS raw data receiving unit that receives the GNSS raw data from the kth point, Wherein the plurality of GNSS satellites comprise different types of satellites, and wherein the previous position estimate and the current position estimate are derived from the estimated position of the GNSS receiver and the plurality of And an estimated clock error of the GNSS receiver for a GNSS satellite, wherein the indirect measurement for the tactical moon includes: A it may include the actual measured values and the virtual measurement value is generated in consideration of the clock error conditions and dynamic conditions as the conditions of the GNSS receivers that are generated in consideration.

According to one embodiment of the present application, the clock error condition is based on the fact that the GNSS receiver is driven by a single oscillator, the clock error increment value of the GNSS receiver for each of the different kinds of satellites (K-1) th time point and the kth time point is an interval in seconds, the dynamic condition condition is a condition that the It may be a condition that the dynamic state of the GNSS receiver is equal to the dynamic state of the GNSS receiver at the kth time point.

According to an embodiment of the present invention, the location area Hatch filter may be configured to determine whether the number of visible satellites at the kth viewpoint satisfies a predetermined number or more based on the acquisition state of the GNSS raw data at the kth viewpoint And an update measurement value generation unit for updating the present position estimate at the kth time point using the indirect measurement value for update to generate an updated measurement value if it is determined that the number of visible satellites is satisfied.

According to an embodiment of the present invention, there is further provided a data processing unit for identifying the GNSS source data as normal data or abnormal data by using a Doppler comparison technique among FDI (Fault Detection and Isolation) techniques, GNSS can be performed considering only normal data among the source data.

According to an embodiment of the present invention, the data processing unit may be configured such that when the difference between the Doppler measurement included in the GNSS raw data provided from the visible satellite of any one of the one or more visible satellites and the increment of the pseudorange is greater than a predetermined first difference , Or if the difference between the Doppler measurement and the increment of the carrier phase measurement is greater than a preset second difference, GNSS raw data provided from any one of the visible satellites can be identified as abnormal data.

The above-described task solution is merely exemplary and should not be construed as limiting the present disclosure. In addition to the exemplary embodiments described above, there may be additional embodiments in the drawings and the detailed description of the invention.

According to the present invention, the estimated precise position information can be applied and applied to various fields such as an autonomous navigation system, a spatial information system, a geodesic / surveying system, and a bridge monitoring system.

According to the above-described task solution of the present invention, the position area Hatch filter can enable precise position estimation in real time by utilizing the incremental value of the carrier phase measurement.

According to the above-mentioned problem solving means, a virtual measurement value is utilized in the casting process of the location area hatch filter, and a fault detection and isolation (FDI) algorithm using a visible satellite is added, The positioning error due to the path can be minimized.

1 is a schematic block diagram of a position estimating apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining an entire area-area Hatch filter algorithm according to an embodiment of the present invention.

3, 4A to 4D, and 5 are experimental examples performed to evaluate the performance of the position estimating apparatus according to an embodiment of the present invention.

6 is a schematic flow diagram of a position estimation method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

It will be appreciated that throughout the specification it will be understood that when a member is located on another member "top", "top", "under", "bottom" But also the case where there is another member between the two members as well as the case where they are in contact with each other.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

The present invention relates to a method and an apparatus for designing a location area hatch filter using multiple GNSSs, and a design of a location area hatch filter utilizing GLONASS, BeiDou, etc. in addition to GPS. The present invention also relates to a multi-satellite navigation group. According to an embodiment of the present invention, the number of visible satellites is improved by utilizing a plurality of GNSS satellites, and a positional area Hatch filter is applied to obtain the number of unknown satellites It is possible to estimate the position information without the processing of FIG. In addition, we can improve the positional accuracy by updating the measured value only when the visible satellite is sufficiently secured. By applying the FDI method using the Doppler measurement, we can detect the measurement value of the channel including the cycle slip or multipath error Can be separated.

Referring to FIG. 1, the position estimation apparatus 100 may include, but is not limited to, a GNSS receiver 110, a data processing unit 120, and a location area Hatch filter 130. Illustratively, the position estimation apparatus 100 may further include position information providing unit (not shown) for providing estimated position information.

GNSS (Global Navigation Satellite System) is one of the most convenient navigation systems that can easily acquire information such as location, speed, and time of various users. GNSS (Satellite Navigation System) is a system that uses satellites to provide information such as location, speed, and time of a target on the ground. The GNSS receiver determines the position of the satellite and the receiver based on the signal transmitted from the GNSS satellite.

The position estimating apparatus 100 can further increase the number of visible satellites by additionally using GLONASS and BeiDou in addition to GPS to form a more precise and continuous multi-satellite navigation group in a poor signal receiving environment in the urban area. In addition, the position estimating apparatus 100 may apply the FDI (Fault Detection and Isolation) technique to all the measured values to enable continuous and precise positioning in the downtown area. Typical pseudorange measurements and carrier phase measurements are used for GNSS-based positioning. The use of carrier phase measurements is very difficult but very accurate compared to pseudorange measurements.

Unlike the basic positioning method using only the pseudo range measurement, the position estimation apparatus 100 can improve the positioning accuracy by using the position area Hatch filter together with the carrier phase measurement. Since the position estimating apparatus 100 utilizes the virtual measurement value in the casting process of the position area Hatch filter, continuous positioning is possible even when there is no visible satellite. The position estimating apparatus 100 can increase the scalability to incorporate other sensors by including the position area Hatch filter.

The GNSS receiver 110 may be provided with GNSS raw data from one or more visible satellites if there is more than one visible satellite of the plurality of GNSS satellites at the kth time point. The plurality of GNSS satellites may comprise different types of satellites. The plurality of GNSS satellites may include GPS satellites, GLONASS satellites, and BeiDou satellites. Each of the GPS satellite, GLONASS satellite, and BeiDou satellite can provide a GPS signal, a GLONASS signal, and a BeiDou signal to the GNSS receiver 110.

The GNSS receiver 110 may be provided with a GPS signal from a GPS satellite. The GPS signal is composed of a carrier frequency, a PRN (Pseudo Random Noise) code modulated by a BPSK (Binary Phase Shift Keying) method, and a navigation message modulated by a BPSK method. The Institute of Electrical and Electronics Engineers Use the defined frequency band of 1 GHz to 2 GHz. The GPS satellite network uses a Code Division Multiple Access (CDMA) scheme.

Also, the GNSS receiver 110 may be provided with a GLONASS signal from the GLONASS satellite. The GLONASS satellite network uses a frequency division multiple access (FDMA) scheme.

In addition, the GNSS receiver 110 may be provided with a BeiDou signal from the BeiDou satellite. The BeiDou satellite can estimate the user's location, speed, and time information as well as GPS satellites. The BeiDou signal consists of the carrier frequency, code and navigation messages, and uses the L frequency band from 1 GHz to 2 GHz, similar to GPS. The carrier frequency uses the specific frequencies B1, B1-2, B2, and B3 among the L bands, which are 1561.098 MHz, 1589.742 MHz, 1207.140 MHz, and 1268.520 MHz, respectively. The B1, B1-2, B2, and B3 signals are composed of the sum of the I channel signal and the Q channel signal having 90 ° phase difference, and the code and the navigation message are modulated by the QPSK (Quadrature Phase Shift Keying) method. The BeiDou satellite network uses a Code Division Multiple Access (CDMA) scheme.

Illustratively, the GNSS receiver 110 may be provided GNSS raw data from each of the GPS satellites and the BeiDou satellites among GPS satellites, GLONASS satellites, and BeiDou satellites at the kth (eg, first) time point. The GNSS receiver 110 may receive the GPS signal from the GPS satellite and receive the BeiDou signal from the BeiDou satellite.

According to one embodiment of the present invention, the data processing unit 120 can identify GNSS raw data as normal data or abnormal data by using a Doppler comparison technique among FDI (Fault Detection and Isolation) techniques. The data processing unit 120 may receive GNSS raw data from the GNSS receiver 110. [ The data processing unit 120 can identify normal data or abnormal data based on the GNSS raw data.

Generally, the channel of the GNSS receiver consists of a delay locked loop (DLL) and a phase locked loop (PLL). The delay tracking circuit uses the code signal to generate a pseudorange measurement, and the phase tracking circuit uses the phase signal to generate a carrier cumulative phase measurement. The measured pseudorange and carrier accumulation phase in a single GNSS receiver includes various errors such as ionospheric delay, tropospheric delay, clock bias, cycle slip, and multipath error .

In addition, since GNSS satellites transmit signals at very high altitudes, they are very low in strength when receiving signals at the receiver. Therefore, it is often the case that unreliable measurement values are obtained due to a cycle slip in which a signal is temporarily disconnected in a downtown area where many signals are interfered with signal propagation such as a high building or an overpass, or a multipath error can see. The Doppler measurements can be obtained by the momentary satellite and receiver movements obtained at the GNSS receiver 110.

The data processing unit 120 can identify the GNSS raw data as normal data or abnormal data by using the FDI technique using Doppler measurements to identify such measurements.

Generally, the Doppler measure is integrated over time to yield a carrier measurement. Therefore, theoretically, the Doppler measurement at the current point is equal to the value obtained by subtracting the equivalent pseudorange using the pseudo distance or the carrier phase at the current point in the equivalent pseudo distance using the pseudo distance or the carrier phase at the previous point. Using this principle, the data processing unit 120 can detect and separate measurement values of a channel including a cycle slip or a multipath error.

The data processing unit 120 may be configured to determine if the difference between the Doppler measurements included in the GNSS raw data provided from any one of the one or more visible satellites and the increment of the pseudoranges is greater than a predetermined first difference or if a Doppler measurement and a carrier phase measurement The GNSS raw data provided from any one of the visible satellites can be identified as abnormal data if the difference is greater than a preset second difference.

According to one embodiment of the present invention, the data processor 120 can detect an equivalent pseudo-range cycle slip using the carrier accumulation phase from Equation (1). In other words, when the difference between the Doppler measurement included in the GNSS raw data provided from the visible satellite of one of the one or more visible satellites and the increment of the pseudorange is greater than a predetermined first difference, Faults can be detected and isolated.

In Equations (1) and (2) described below,

,

Is the wavelength of the carrier phase measurements, pseudorange measurements, Doppler measurements, and GNSS signals for channel j at each kth viewpoint

and

Is an arbitrary constant.

[Equation 1]

In Equation (1)

Is the increment of the carrier cumulative phase measurement from the ( k -1) th point to the k th point for the jth satellite,

Is the Doppler measurement at the kth point for the jth satellite, i. E.

Equivalent quantity of < RTI ID = 0.0 >

Is the difference between the increment of the carrier cumulative phase measurement from the ( k- 1) th point to the k- th point of time for the j-th satellite and the Doppler measurement at the k- th point of time.

The data processing unit 120 may be based on Equation (1)

The value of

The failure of the corresponding channel can be detected and separated. here,

May be a predetermined constant so as to have a value suitable for the failure detection.

Also, the data processing unit 120 can detect an unreliable pseudorange measurement by including an error such as a multipath error from the equation (2). In other words, the data processing unit 120 can identify the GNSS raw data provided from any one of the visible satellites as abnormal data when the difference between the Doppler measurement and the increment of the carrier phase measurement is larger than the preset second difference.

&Quot; (2) "

In Equation 2,

Is the increment of the pseudorange measurement from the ( k -1) th point to the k th point for the jth satellite,

Is the Doppler measurement at the kth point for the jth satellite, i. E.

Is an equivalent quantity.

Is the difference value of the Doppler measurements in increments and k-th point in the pseudorange measurements of the k th point in the second point in time (k -1) for the j-th satellite.

The data processing unit 120 may be based on Equation (2)

The value of

The failure of the corresponding channel can be detected and separated. here,

May be a predetermined constant so as to have a value suitable for fault detection.

The data processing unit 120 may transmit the RINEX file format to the location area hatch filter 130. The Receiver Independent Exchange Format (RINEX) file format is a universal format that allows users to efficiently utilize GNSS data that is handled differently by GNSS receiver manufacturers.

According to one embodiment of the present invention, the location area Hatch filter 130 may include a determination unit 131 and an update measurement value generation unit 132. [

Determination unit 131 may determine whether or not based on the acquired status of the GNSS raw data in the k-th point in time to meet the number more than the number of visible satellites at the k th point set in advance.

With respect to the Number of Visible Satellite, four or more satellites can be tracked as visible satellites in order to calculate the automatic three-dimensional location (latitude, longitude, height, time) . Although it is possible to calculate the three-dimensional position of the unknown using only four satellites, it is more desirable to obtain GNSS raw data from more than five satellites, since observing more satellites provides a mathematically stronger location. When performing a GPS survey, redundant satellites provide surplus carrier-phase observations and provide a safety factor over time when a cycle slip occurs. In the case of real-time surveys, five satellites are required for automatic initialization.

Illustratively, the determination unit 131 can determine whether or not the number of visible satellites satisfies a predetermined number (for example, five) or more in order to perform accurate and continuous positioning in the urban area.

The location area Hatch filter 130 may perform the casting month and measurement value updating process considering only the normal data among the GNSS raw data provided from the data processing unit 120. [ The location area Hatch filter 130 can improve the positioning accuracy and the failure detection capability by performing the casting month and measurement value update process considering only the normal data among the GNSS raw data. Illustratively, the location area hatch filter 130 utilizes the disparity value of the carrier phase measurements in the casting process and the pseudorange measurements in the process of updating the measurements.

The location domain hatch filter 130 may increment the carrier phase measurements of each of the GPS, GLONASS, and BeiDou. The location area hatch filter 130 can utilize the incremental value without obtaining the unknown number. Since the carrier phase measurement includes unspecified number of components, it can not be used without complicated processing. However, if the increment value obtained by subtracting the measured value from the current point and the previous point is used, the number of unknowns can be canceled without any additional processing.

The location domain hatch filter 130 may estimate the true state from a total of six state variables including three 3D locations and receiver clock errors for each of GPS, GLONASS, and BeiDou. In other words, the location area Hatch filter 130 may estimate the receiver error for each GNSS other than the 3D (X, Y, Z) location at the location utilizing the GNSS. In addition, since the position-area Hatch filter 130 utilizes three GNSSs such as GPS, GLONASS, and BeiDou, it is possible to estimate a total of six state variables including three receiver clock errors except for three 3D positions.

&Quot; (3) "

In Equation (3)

Is a true state variable that the filter estimates. At the kth time point, the three-dimensional position of the GNSS receiver

And the receiver clock error for each GNSS

.

Is the 3-axis coordinate of the ECEF coordinate system

,

And

Is the receiver clock error for GPS, the receiver clock error for GLONASS and the receiver clock error for BeiDou

,

And

.

Location area Hatch filter 130 is cast dalyong using an indirect measurement of the k-th point in time than the previous (k -1) for the previous position estimate at the second point in geumbeon position estimate of the k th point be cast month (propagation time) . In other words, the position area Hatch filter 130 calculates the posterior estimation value < RTI ID = 0.0 >

An estimate of the k-th viewpoint before

To make time propagation,

Lt; / RTI > Indirect measurement

May include actual measurements and virtual measurements.

The location area hatch filter 130 may perform the casting process based on Equation (4).

&Quot; (4) "

In Equation 4,

Is an indirect measure used in the casting process,

Is the increment of each GNSS carrier phase measurement, D is the difference of each GNSS clock error increment,

Is the dynamic state of the prior-point receiver. Also,

Is the observation matrix of the casting process,

Is the eye angle vector for each GNSS satellite.

Each of the previous and current position estimates may include an estimated position of the GNSS receiver and an estimated clock error of the GNSS receiver for a plurality of GNSS satellites.

The clock error condition may be a condition that assumes that the clock error increments of the GNSS receiver for each of the different kinds of satellites are equal, based on the fact that the GNSS receiver is driven by one oscillator. Illustratively, the clock error condition is the difference between the absolute value of the receiver clock error for each of the GPS satellite, the GLONASS satellite and the BeiDou satellite in a GNSS receiver driven by the same oscillator, The value may be a condition that is assumed to be the same. In other words, the clock error conditions are the same for the GNSS receiver driven by the same transducer, but the receiver clock error increments for each GNSS are the same for a short time, although there is a difference in the receiver clock error absolute value for each GNSS, While the dynamic state of the receiver may be assumed to be the same. For example, since the number of required measurement values is equal to or larger than the number of visible satellites, the position estimation can be performed even when the number of visible satellites is zero.

The indirect measurement for the tachometer may include a virtual measurement that is generated considering the GNSS raw data and the actual measurement value and the GNSS receiver clock error condition and dynamic condition condition. The actual measurements may be generated using increments of the carrier phase measurements for each of the different kinds of satellites obtained from the GNSS raw data. Illustratively, the actual measurements may be generated utilizing incremental values of the equivalent pseudoranges using the carrier phase measurements for each of GPS, GLONASS, and BeiDou. In addition, the virtual measurement can be generated utilizing the receiver clock error constraint between each GNSS and the dynamic state at the previous time point.

Dynamic state condition (k -1) th time point on the basis of the fact that the interval spacing in seconds between the k-th point (k -1) GNSS receiver in a dynamic state and the k-th point of a GNSS receiver in a second time Lt; RTI ID = 0.0 > the < / RTI > As an example, since the state variable is estimated at intervals of a short second such as 1 second, it can be assumed that the dynamic states of the GNSS receiver at the previous time point (( k -1)) and at the current time point ( kth ) have.

Here, the unit of seconds means a unit of one digit seconds within 10 seconds. For example, the interval between the ( k- 1) th point and the kth point may be set to an interval of 1 second, but the present invention is not limited thereto. Also, the unit of seconds does not mean only a unit of a natural number type, but can be understood as a concept including a unit of a positive real number type.

The location area hatch filter 130 may generate updated measurements from the update measurement generator 132 to overcome the limitations of the casting process. In other words, since the location area Hatch filter 130 utilizes the increment of the measurement, there is a limitation of relative position estimation, and since the virtual measurement is utilized, the error can be accumulated over time.

The update measurement value generation unit 132 can perform the measurement update only when it is determined that the visible satellite of the determination unit 131 is sufficiently secured. GNSS pseudorange measurements can be performed to determine whether the number of visible satellites meets a predetermined number or more and to perform a measurement update because the position accuracy is lowered when the error is relatively large and the number of visible satellites is not sufficient .

When it is determined that the number of visible satellites is satisfied, the update measurement value generation unit 132 can update the current position estimate at the k- th time point using the update indirect measurement value to generate an updated measurement value. In other words, the updated measure producing unit 132 around the estimate of the k th point

Then,

To perform a measurement update to update the measurement value

Lt; / RTI >

The update measure may be generated using pseudorange measurements obtained via GNSS raw data provided from one or more visible satellites.

The update measure generation unit 132 may update the measurement based on equation (5).

&Quot; (5) "

In Equation (5)

Is an indirect measure used in the process of updating a measurement, and includes each GNSS pseudorange measurement.

Is the observation matrix of the measurement update process,

Represents the eye angle vector for each GNSS satellite.

FIG. 2 is a diagram for explaining an entire area-area Hatch filter algorithm according to an embodiment of the present invention. Referring to FIG. 2, the location area Hatch filter 130 may perform a time propagation process and a measurement update process repeatedly after an initialization process.

According to one embodiment of the present application, the location domain Hatch filter 130 is configured to use two indirect measurements < RTI ID = 0.0 >

Wow

It is possible to recursively form a position estimation method.

Referring to FIG. 2, in order to reflect characteristics of the downtown area where frequent appearance of the satellite occurs,

Area Hatch filter 130 that performs the casting process and the measurement value update process repeatedly after the initialization process. Satellite selection matrix

Is composed of 1 and 0, and a value of 1 is given to channels of satellites which are both reliable at the ( k- 1) -th point and the k- th point.

The location area hatch filter 130 may perform an initialization procedure using GPS pseudorange measurements, GLONASS pseudorange measurements, and BeiDou pseudo range measurements.

The location area hatch filter 130 may perform an initialization process based on Equation (7).

&Quot; (7) "

In Equation (7), H is the observation matrix, X is the state variable estimated by the filter,

Is a satellite selection matrix, P is an error covariance matrix,

Indicates a priori meaning a casting month, and a posteriori indicating a measure update.

Also, the location area hatch filter 130 may perform the casting process based on Equation (8).

&Quot; (8) "

H is the observation matrix, X is the state variable estimated by the filter,

Is a satellite selection matrix, P is an error covariance matrix,

Is the moon indirect measurement,

K is the Hatch-type gain (weighting) matrix, and superscript

Weight matrix

And errors that occur with indirect measurements

Wow

Is as follows.

Is the error of the indirect measure correlated to the previous point

Is an error to an indirect measure that does not correlate to the previous point.

The location area hatch filter 130 may perform an initialization process by applying GPS pseudorange measurements, GLONASS pseudorange measurements, and BeiDou pseudo range measurements. In addition, the location domain hatch filter 130 may be implemented by applying the GPS carrier phase measurement increment, the GLONASS carrier phase measurement increment, the BeiDou carrier phase measurement increment, the difference between the GNSS time difference increments of the receiver, Can be performed. The location area Hatch filter 130 may perform a process of updating a measurement value by applying a GPS pseudorange measurement, a pseudo range measurement of GLONASS, and a BeiDou pseudo range measurement. , It is possible to perform the update of the measurement month and the update of the measurement value repeatedly.

That is, the position area hatch filter 130 is composed of a casting process and a measurement value updating process. In the casting process, the parallax value of the carrier phase measurement value is used. In the process of updating the measurement value, the pseudo range measurement value is used. The measurement update procedure can be performed only when the GNSS satellite is sufficiently secured.

3, 4A to 4D, and 5 are experimental examples performed to evaluate the performance of the position estimation apparatus 100 according to an embodiment of the present invention.

In order to evaluate the performance of the position estimating apparatus 100, an urban vehicle test was performed in Gangnam Teheranro, which is one of the poorest signal receiving environments in Korea, and the GNSS receiver was a ProPak6 of NovAtel. We obtained the results by using GPS snapshot algorithm, GPS / GLONASS / BeiDou snapshot algorithm, GPS location area Hatch filter, and GPS / GLONASS / BeiDou location area Hatch filter.

FIG. 3 is a table for comparing the results obtained by using the GPS snapshot algorithm, the GPS / GLONASS / BeiDou snapshot algorithm, the GPS position area Hatch filter, and the GPS / GLONASS / BeiDou location area Hatch filter .

FIGS. 4A to 4D show positioning results of four GPS / GLONASS / BeiDou snapshot algorithms, a GPS position area Hatch filter, and GPS / GLONASS / BeiDou position area Hatch filter for a single acquired data Fig.

5 is a graph comparing the number of visible satellites utilizing GPS, GPS / GLONASS, and GPS / GLONASS / BeiDou.

The GPS snapshot algorithm has many locations that are not positional or inaccurate, and the GPS / GLONASS / BeiDou snapshot algorithm shows somewhat improved trajectory, though it is not smooth. It is confirmed that there are some inaccurate intervals when using the GPS location area hatch filter, but the GPS snapshot algorithm has improved much in comparison with the GPS snapshot algorithm. In addition, when the GPS / GLONASS / BeiDou location area Hatch filter is used, a smooth trajectory is calculated without a section that is not estimated.

In terms of the number of visible satellites, GPS, GPS / GLONASS, and GPS / GLONASS / BeiDou are compared, and the number of visible satellites increases with GNSS added. As shown in FIG. 3, the availability of the location information of the GPS snapshot and the GPS / GLONASS / BeiDou algorithm was 78.5% and 96.4% based on the number of visible satellites. % Of location information availability.

In the experimental example of the position estimating apparatus 100, a position area Hatch filter for integrating GPS, GLONASS, and BeiDou is proposed for accurate and continuous position estimation in urban areas. By using GLONASS and BeiDou in addition to GPS, it is possible to mitigate the problem of failing to acquire visible satellite in downtown area. In addition, the FDI technique using Doppler measurements was added to minimize errors caused by cycle slip and multipath in urban areas.

As a result of the experiment, GPS and GPS / GLONASS / BeiDou integrated positioning using snapshot algorithm showed 78.5% and 96.4% location information availability, respectively. GPS / GLONASS / BeiDou integration Positioning showed 100% availability of location information. Also, based on the smoothness of the trajectory, it is confirmed that the proposed filter can improve the accuracy of location estimation in urban areas. The number of visible satellites was also significantly increased when multiple GNSS were used than when using a single GNSS.

6 is a schematic flow diagram of a position estimation method according to one embodiment of the present application. 6 may be performed by the position estimation apparatus 100 according to the embodiment of the present invention described above. Therefore, even if omitted in the following description, the description of the position estimating apparatus 100 through Figs. 1 to 5 also applies to Fig.

In step S610, the position estimating apparatus 100 can receive GNSS raw data from one or more visible satellites when there is at least one visible satellite among a plurality of GNSS satellites at the kth time point. At this time, the plurality of GNSS satellites may include different types of satellites.

In step S620, the position estimation device 100 includes casting the previous position estimates of the second of the previous (k -1) point than the k th point, using an indirect measurement dalyong casting location area geumbeon position estimate of the k th point month (time propagation) process. Herein, the previous position estimate and the current position estimate include the estimated position of the GNSS receiver and the estimated clock error of the GNSS receiver for the plurality of GNSS satellites, and the indirect measurement value for the tactical maze includes the actual measurements generated in consideration of the GNSS raw data, And may include a virtual measurement that is generated in consideration of the clock error condition and the dynamic condition of the receiver.

In step S630, the position estimation device 100, based on the acquired status of the GNSS raw data in the k th point it may determine whether it meets the number more than the number of visible satellites at the k th point set in advance.

In step S640, if it is determined that the number of visible satellites is satisfied, the position estimating apparatus 100 can update the current position estimate at the kth time point using the indirect measurement value for update to generate the updated measurement value.

Although not shown, if it is determined that the number of visible satellites is satisfied based on the determination result of whether or not the number of visible satellites satisfies a predetermined number or more, the position estimating apparatus 100 updates the position estimate to generate an updated measurement value, Information can be provided. On the other hand, if it is determined that the number of visible satellites is not satisfied, the position estimation apparatus 100 may provide the estimated position information without updating the position estimate, but the present invention is not limited thereto.

However, the embodiment described with reference to FIG. 6 is only one of various embodiments of the present invention, and thus is not construed as being limited thereto, and various embodiments may exist.

The location estimation method according to one embodiment of the present invention may be implemented in the form of a program command or an application program that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims

In the position estimation method,

(a) receiving GNSS raw data from the one or more visible satellites when the GNSS receiver has at least one visible satellite of the plurality of GNSS satellites at the kth time point;

(b) a location area Hatch filter dalyong the casting by using an indirect measurement of k prior to the second time point (k -1) for the previous month casting position estimate at the second point in geumbeon position estimate at the k-th time (propagation time ),

Wherein the plurality of GNSS satellites comprise different types of satellites,

Wherein the previous position estimate and the current position estimate comprise an estimated position of the GNSS receiver and an estimated clock error of the GNSS receiver for the plurality of GNSS satellites,

Wherein the indirect measurement for the tactical cast includes a virtual measurement that is generated in consideration of an actual measurement value generated in consideration of the GNSS source data and a clock error condition and a dynamic condition condition of the GNSS receiver, Hatch filter based location estimation method.
The method according to claim 1,

Wherein the clock error condition is a condition that assumes that the clock error increment value of the GNSS receiver for each of the different kinds of satellites is the same based on that the GNSS receiver is driven by one oscillator,

The dynamic status conditions, and the dynamic state of the (k-1) th point and the k based on the fact that the interval spacing in seconds between the first time point, wherein the (k -1) the GNSS receiver in a second time Is a condition assuming that the dynamic state of the GNSS receiver at the kth time point is the same.
The method according to claim 1,

Wherein the actual measurements are generated using an increment of the carrier phase measurements for each of the different types of satellites obtained from the GNSS raw data.
The method of claim 3,

(c) a location area Hatch filter, determining whether the number of the number of satellites in the predetermined k-th point in time based on the acquired status of the GNSS raw data in the k-th point in time to meet the phase; And

(d) updating the current position estimate at the k- th time point using the indirect measurement for update and generating an updated measurement if the number of visible satellites is determined to be satisfied, Area Hatch Filter Based Position Estimation Method.
5. The method of claim 4,

Wherein the update measurements are generated using pseudorange measurements obtained via GNSS raw data provided from the one or more visible satellites.
The method according to claim 1,

Wherein the different types of satellites include GPS satellites, GLONASS satellites, and BeiDou satellites.
The method according to claim 1,

In the step (a), the data processor identifies the GNSS primitive data as normal data or abnormal data using a Doppler comparison technique among FDI (Fault Detection and Isolation) techniques,

Wherein the step (b) is performed in consideration of only normal data among the GNSS primitive data.
8. The method of claim 7,

In the step (a), if the difference between the Doppler measurement included in the GNSS raw data provided from any one of the visible satellites of the one or more visible satellites and the increment of the pseudorange is greater than a preset first difference Or if the difference between the Doppler measurement and the increment of the carrier phase measurement is greater than a preset second difference, identifying the GNSS raw data provided from either of the visible satellites as abnormal data. Hatch filter based location estimation method.
In the position estimating apparatus,

a GNSS receiver receiving GNSS raw data from the at least one visible satellite if at least one of the plurality of GNSS satellites is present at a kth time point;

Casting the dalyong older than the k-th point in time using the indirect measurement (k-1) th casting a previous position estimate of the time to geumbeon position estimate at the k th point month including the location area Hatch filter (time propagation) However,

Wherein the plurality of GNSS satellites comprise different types of satellites,

Wherein the previous position estimate and the current position estimate comprise an estimated position of the GNSS receiver and an estimated clock error of the GNSS receiver for the plurality of GNSS satellites,

Wherein the indirect measurement for the tactical cast includes a virtual measurement that is generated in consideration of an actual measurement value generated in consideration of the GNSS source data and a clock error condition and a dynamic condition condition of the GNSS receiver, Hatch filter based position estimator.
10. The method of claim 9,

The clock error condition is a condition that assumes that the clock error increment value of the GPS receiver for each of the different kinds of satellites is the same based on that the GNSS receiver is driven by one oscillator,

The dynamic state conditions, dynamic state of the (k -1) th point and the k based on the fact that the interval spacing in seconds between the first time point, wherein the (k -1) of the GPS receiver at the second point in time and Is a condition that the dynamic state of the GPS receiver at the k- th time point is assumed to be the same.
10. The method of claim 9,

Wherein the actual measurements are generated using an increment of carrier phase measurements for each of the different types of satellites obtained from the GNSS raw data.
12. The method of claim 11,

The location-area Hatch filter comprises:

Judging unit for judging whether the number obtained on the basis of the state of the raw GNSS data, the number of visible satellites at the k th point previously set in the k-th point in time to meet the phase; And

And an update measurement value generation unit for updating the current position estimate at the k- th time point using the indirect measurement value for update and generating an update measurement value when it is determined that the number of visible satellites is satisfied, Filter based position estimator.
13. The method of claim 12,

Wherein the updated measurements are generated using pseudorange measurements obtained via GNSS raw data provided from the one or more visible satellites.
10. The method of claim 9,

Wherein the different types of satellites include GPS satellites, GLONASS satellites, and BeiDou satellites.
10. The method of claim 9,

Further comprising a data processing unit for identifying the GNSS raw data as normal data or abnormal data by using a Doppler comparison technique among FDI (Fault Detection and Isolation) techniques,

Wherein the location area Hatch filter is performed considering only normal data among the GNSS raw data.
16. The method of claim 15,

Wherein the data processing unit is operable when the difference between the Doppler measurement included in the GNSS raw data provided from any one of the one or more visible satellites and the increment of the pseudorange is greater than a predetermined first difference or the Doppler measurement and the carrier phase And identifying the GNSS raw data provided from any one of the visible satellites as abnormal data when the difference between the measured values is greater than a predetermined second difference.
A computer-readable recording medium on which a program for executing the method of any one of claims 1 to 8 is recorded.