GNSS carrier phase ambiguity processing method and electronic equipment

Abstract

The invention discloses a GNSS (Global Navigation Satellite System) carrier phase ambiguity processing method and electronic equipment. The method comprises the following steps: establishing a carrier phase ambiguity resolving model; determining a vector expression of integer ambiguity in the carrier phase ambiguity resolving model; calculating the integer ambiguity of the k-th epoch continuous visible satellite based on the integer ambiguity of the (k-1) th epoch visible satellite and a baseline vector obtained by inertial navigation assistance; and substituting the integer ambiguity of the continuous visible satellites into an ambiguity resolving model, resolving the integer ambiguity of the new visible satellite of the kth epoch, and further obtaining the integer ambiguity of all the visible satellites. According to the method, the integer ambiguity in the GNSS carrier phase observed quantity is rapidly solved through the auxiliary information output by inertial navigation, and the ambiguity solving efficiency under the condition that the number of visual satellites is large is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of GNSS high-precision positioning technology, and more specifically, to a GNSS carrier phase ambiguity processing method and electronic equipment. Background Art

[0002] High-precision Global Navigation Satellite System (GNSS) applications rely on carrier phase observations of satellites. Carrier phase is a measure of the geometric distance between the satellite and the receiver antenna. When using high-precision antennas, carrier phase observations can achieve millimeter-level accuracy. However, carrier phase observations often contain errors equal to an integer number of carrier wavelengths, known as carrier phase integer ambiguities. Once these integer ambiguities are resolved, carrier phase observations can be used as precise geometric distance measurements, enabling a variety of high-precision carrier phase-based GNSS applications.

[0003] With the continuous development of GNSS in various countries, there are now over 100 navigation satellites in orbit, and dozens of navigation satellites can be observed and used at any location on Earth at any given time. Although high-precision GNSS applications such as real-time kinematic positioning (RTK) generally only require five or six satellites to achieve good results, more visible satellites are beneficial for improving the accuracy of the solution. A large number of redundant satellites not only helps improve the satellite's positioning precision factor, raising the theoretical upper limit of positioning accuracy, but also reduces the impact of less accurate observations on the solution.

[0004] But at the same time, more visible satellites also mean that the calculation process will be more complicated, and more observation data also means that the solution efficiency will be lower.

[0005] At present, there is still a need to develop a GNSS carrier phase ambiguity processing method based on inertial navigation assistance.

[0006] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0007] The present invention proposes a GNSS carrier phase ambiguity processing method and electronic equipment, which can estimate the integer ambiguity in the GNSS carrier phase observation quantity through the auxiliary information output by the inertial navigation, thereby ensuring the efficiency of positioning solution.

[0008] In a first aspect, an embodiment of the present disclosure provides a GNSS carrier phase ambiguity processing method, comprising: Establish a carrier phase ambiguity resolution model; Determining a vector expression for integer ambiguity in the carrier phase ambiguity resolution model; Based on the integer ambiguity of the visible satellites at the k-1th epoch and the baseline vector obtained with the aid of inertial navigation, the integer ambiguity of the continuously visible satellites at the kth epoch is calculated; The integer-cycle ambiguities of continuously visible satellites are substituted into the ambiguity resolution model to resolve the integer-cycle ambiguities of the newly visible satellites at the kth epoch, and then the integer-cycle ambiguities of all visible satellites are obtained.

[0009] Preferably, the carrier phase ambiguity resolution model is: E(y)=Aa+Bb, D(y)=Q yy where E(·) and D(·) represent the expectation and variance operators, respectively; y represents the column vector consisting of the difference between the carrier phase observation and the pseudorange observation and the satellite-antenna geometric distance; a represents the integer ambiguity vector, ; b represents the baseline three-dimensional vector, ; A is the coefficient matrix, which contains the carrier phase wavelength; B is the coefficient matrix, which contains the unit vector of the satellite observation direction; express A set of n-dimensional integer vectors, represents a set of three-dimensional real vectors, Q yy represents the covariance matrix of y.

[0010] Preferably, the vector expression of the integer ambiguity is: a=[a 12 , a 13 , a 14 ,…, a 1s ] T in, , a 1i Indicates that in satellite 1, i The carrier phase integer ambiguity in the form of double difference between ; satellite number 1 represents the reference satellite; Indicates the reference station to the satellite i The carrier phase integer ambiguity contained in the carrier phase observation; Indicates user's satellite i The carrier phase integer ambiguity contained in the carrier phase observation, i=2,3,…,s.

[0011] Preferably, calculating the integer ambiguities of the continuously visible satellites at the k-th epoch based on the integer ambiguities of the visible satellites at the k-1 epoch and the baseline vector obtained with the aid of inertial navigation comprises: According to the output of the inertial navigation module on the user carrier, the change of the user antenna coordinates from the k-1th epoch to the kth epoch is calculated as the change of the baseline three-dimensional vector; Calculate the baseline three-dimensional vector of the kth epoch according to the change of the baseline three-dimensional vector; Calculate the satellite-antenna distance corresponding to each satellite based on the baseline three-dimensional vector and satellite coordinates at the kth epoch; The difference between the satellite-antenna distance and the satellite-antenna distance at the k-1th epoch is used to obtain the change in satellite-antenna distance from the k-1th epoch to the kth epoch, which is used as the carrier phase change. Calculate the carrier phase integer ambiguity of the kth epoch according to the carrier phase change; Satellite 1 to satellite s are visible at both the k-1th epoch and the kth epoch. The double-difference ambiguity vectors of the continuously visible satellites at the kth epoch are calculated.

[0012] Preferably, the change in the baseline three-dimensional vector is: △u=[△x r ,△y r ,△z r ] T Among them, △u is the change of the baseline three-dimensional vector, △x r , △y r , △z r are the changes in the x, y, and z directions respectively.

[0013] Preferably, the baseline three-dimensional vector is: b(k)= b(k-1)+△u Among them, b(k-1) and b(k) are the three-dimensional baseline vectors of the k-1th epoch and the kth epoch respectively.

[0014] Preferably, the carrier phase change is: , in, Represents the carrier phase observation in double-difference form, i=2,3,…,s.

[0015] Preferably, the double-difference ambiguity vector of the continuously visible satellites at the kth epoch is: a 1~s (k)=[a 12 (k), a 13 (k),…, a 1s (k)] T .

[0016] Preferably, substituting the integer ambiguities of the consecutive visible satellites into the ambiguity resolution model, resolving the integer ambiguities of the newly visible satellites at the k-th epoch, and then obtaining the integer ambiguities of all visible satellites includes: Substituting the double-difference ambiguity vector of the continuously visible satellites at the k-th epoch into the carrier phase ambiguity resolution model to obtain the carrier phase ambiguity resolution model of the k-th epoch, wherein the carrier phase ambiguity resolution model of the k-th epoch is an equation containing only the carrier phase integer ambiguities of the newly added satellites from the k-1-th epoch to the k-th epoch as unknowns; Resolve the carrier phase ambiguity resolution model for the k-th epoch.

[0017] In a second aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising: a memory storing executable instructions; A processor runs the executable instructions in the memory to implement the GNSS carrier phase ambiguity processing method.

[0018] Its beneficial effects are: 1. In high-precision GNSS systems, the user antenna coordinate changes output by the inertial navigation system are used to conveniently obtain the carrier phase ambiguity parameters of continuously visible satellites in the new epoch; 2. When the number of observed GNSS satellites increases, the number of integer ambiguities to be solved in the carrier phase ambiguity resolution process is effectively reduced, avoiding the problem that the efficiency of conventional ambiguity resolution algorithms is significantly reduced due to the increase in the number of satellites.

[0019] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0021] Figure 1 The flowchart shows the steps of a GNSS carrier phase ambiguity processing method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0023] To facilitate understanding of the solutions and effects of the embodiments of the present invention, two specific application examples are given below. Those skilled in the art should understand that the examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way. Example 1

[0024] Figure 1 The flowchart shows the steps of a GNSS carrier phase ambiguity processing method according to an embodiment of the present invention.

[0025] like Figure 1 As shown, the GNSS carrier phase ambiguity processing method includes: step 101, establishing a carrier phase ambiguity resolution model; step 102, determining the vector expression of the integer ambiguity in the carrier phase ambiguity resolution model; step 103, calculating the integer ambiguity of the continuously visible satellites at the k-1 epoch based on the integer ambiguity of the visible satellites at the k-1 epoch and the baseline vector obtained with the aid of inertial navigation; step 104, substituting the integer ambiguity of the continuously visible satellites into the ambiguity resolution model, resolving the integer ambiguity of the newly visible satellites at the k epoch, and then obtaining the integer ambiguity of all visible satellites.

[0026] In one example, the carrier phase ambiguity resolution model is: E(y)=Aa+Bb, D(y)=Q yy where E(·) and D(·) represent the expectation and variance operators, respectively; y represents the column vector consisting of the difference between the carrier phase observation and the pseudorange observation and the satellite-antenna geometric distance; a represents the integer ambiguity vector, ; b represents the baseline three-dimensional vector, ; A is the coefficient matrix, which contains the carrier phase wavelength; B is the coefficient matrix, which contains the unit vector of the satellite observation direction; express A set of n-dimensional integer vectors, represents a set of three-dimensional real vectors, Q yy represents the covariance matrix of y.

[0027] In one example, the vector representation of the integer ambiguity is: a=[a 12 , a 13 , a 14 ,…, a 1s ] T in, , a 1i Indicates that in satellite 1, i The carrier phase integer ambiguity in the form of double difference between ; satellite number 1 represents the reference satellite; Indicates the reference station to the satellite i The carrier phase integer ambiguity contained in the carrier phase observation; Indicates user's satellite i The carrier phase integer ambiguity contained in the carrier phase observation, i=2,3,…,s.

[0028] In one example, calculating the integer ambiguities of the continuously visible satellites at the kth epoch based on the integer ambiguities of the visible satellites at the k-1th epoch and the baseline vector obtained with inertial navigation assistance includes: According to the output of the inertial navigation module on the user carrier, the change of the user antenna coordinates from the k-1th epoch to the kth epoch is calculated as the change of the baseline three-dimensional vector; Calculate the baseline three-dimensional vector of the kth epoch according to the change of the baseline three-dimensional vector; Calculate the satellite-antenna distance corresponding to each satellite based on the baseline three-dimensional vector and satellite coordinates at the kth epoch; The difference between the satellite-antenna distance and the satellite-antenna distance at the k-1th epoch is used to obtain the change in satellite-antenna distance from the k-1th epoch to the kth epoch, which is used as the carrier phase change. Calculate the carrier phase integer ambiguity of the kth epoch according to the carrier phase change; Satellite 1 to satellite s are visible at both the k-1th epoch and the kth epoch. The double-difference ambiguity vectors of the continuously visible satellites at the kth epoch are calculated.

[0029] In one example, the change in the baseline 3D vector is: △u=[△x r ,△y r ,△z r ] T Among them, △u is the change of the baseline three-dimensional vector, △x r , △y r , △z r are the changes in the x, y, and z directions respectively.

[0030] In one example, the baseline 3D vector is: b(k)= b(k-1)+△u Among them, b(k-1) and b(k) are the three-dimensional baseline vectors of the k-1th epoch and the kth epoch respectively.

[0031] In one example, the carrier phase change is: , in, Represents the carrier phase observation in double-difference form, i=2,3,…,s.

[0032] In one example, the double-difference ambiguity vector of continuously visible satellites at epoch k is: a 1~s (k)=[a 12 (k), a 13 (k),…, a 1s (k)] T .

[0033] In one example, the integer ambiguities of consecutive visible satellites are substituted into the ambiguity resolution model to resolve the integer ambiguities of the newly visible satellites at the kth epoch, thereby obtaining the integer ambiguities of all visible satellites. Substitute the double-difference ambiguity vector of the continuously visible satellites at the k-th epoch into the carrier phase ambiguity resolution model to obtain the carrier phase ambiguity resolution model of the k-th epoch. The carrier phase ambiguity resolution model of the k-th epoch is an equation that only contains the carrier phase integer ambiguities of the newly added satellites from the k-1-th epoch to the k-th epoch as unknowns. Resolve the carrier phase ambiguity resolution model for the kth epoch.

[0034] Specifically, in GNSS applications, whether for positioning, orientation, monitoring or other applications, one or more GNSS antennas are required to collect observations of visible satellites. Among them, each antenna can collect carrier phase observations and pseudorange observations for the signals broadcast by each satellite on each frequency point. GNSS carrier phase observations and pseudorange observations are the two basic observations for GNSS positioning. Carrier phase observations refer to the difference between the carrier phase and the reference phase of the satellite signal received by the receiver. It has centimeter-level or even millimeter-level accuracy, but is affected by integer-cycle ambiguity. Pseudorange observations refer to the difference between the propagation time of the satellite signal received by the receiver and the satellite launch time. It is not affected by integer-cycle ambiguity, but its accuracy is only at the meter level.

[0035] The carrier phase ambiguity resolution model can be expressed as: E(y)=Aa+Bb, D(y)=Q yy where E(·) and D(·) denote the expectation and variance operators, respectively; y represents a column vector consisting of the differences between the carrier phase observations and the pseudorange observations and the satellite-antenna geometric distance; a represents the integer ambiguity vector; b represents the baseline three-dimensional vector; A is a coefficient matrix containing the carrier phase wavelength; and B is a coefficient matrix containing the unit vector of the satellite observation direction, which can be obtained from the receiver single-point positioning coordinates and the satellite coordinates, while the satellite coordinates can be obtained from the satellite ephemeris parsed from the satellite signal.

[0036] This implementation uses real-time kinematic positioning (RTK) as an example. In RTK mode, y represents a column vector consisting of two types of data: 1) the difference between the carrier phase observation and the satellite-antenna geometric distance; and 2) the difference between the pseudorange observation and the satellite-antenna geometric distance. a represents the unknown integer ambiguity vector; b Represents the unknown baseline three-dimensional vector. Among them, y and a It is a double-difference form, that is, the inter-station and inter-satellite differential form. b It can be expressed as: b=[x ru , y ru , z ru ] T b is the relative coordinate of the user relative to the reference station, subscript r 、 u Indicates reference station (reference) and user (user).

[0037] The integer ambiguity vector in double difference form can be expressed as: a=[a 12 , a 13 , a 14 ,…, a 1s ] T .

[0038] Assume that the current epoch is k-1, the number of visible satellites is s, and the carrier phase integer ambiguity has been resolved. When the kth epoch comes, assuming that two new satellites are received, the number of visible satellites is s+2. Next, the integer ambiguity processing in the kth epoch is carried out: According to the output of the inertial navigation module on the user carrier, the change of the user antenna coordinates from the k-1th epoch to the kth epoch is first calculated △u=[△x r ,△y r ,△z r ] TSince the reference station is stationary, △u can also be regarded as the change in the baseline vector. Since the inertial navigation can maintain high accuracy in a short period of time, the three-dimensional baseline vector at the kth epoch can be obtained as: b(k)= b(k-1)+△u The coordinates of the satellite at each moment can be calculated from the satellite broadcast ephemeris. After calculating the baseline vector from the above formula, combined with the satellite coordinates, the satellite-antenna distance corresponding to each satellite can be calculated. The difference between the satellite-antenna distance and the satellite-antenna distance at the k-1th epoch is used to obtain the change in the satellite-antenna distance from the k-1th epoch to the kth epoch. This change can be regarded as an estimate of the carrier phase change, namely: .

[0039] In the above formula, a 1i (k-1) has been solved in the k-1th epoch, only a 1i (k) is unknown. Therefore, we can find a according to the above formula. 1i (k), i=2,3,…,s.

[0040] Since satellites 1 to s are visible at both the k-1th epoch and the kth epoch, the double-difference ambiguity vector a of the continuously visible satellites at the kth epoch can be calculated according to the above formula: 1~s (k): a 1~s (k)=[a 12 (k), a 13 (k),…, a 1s (k)] T will a 1~s Substituting (k) into the carrier phase ambiguity resolution model, we can obtain: E(y)=Aa 1~s+2 (k)+Bb, D(y)=Q yy , , a 1~s+2 (k)=[a 12 (k), a 13 (k),…, a 1s (k),a 1,s+1 (k),a 1,s+2 (k)] T

[0041] At this time, only a 1,s+1 (k) and a 1,s+2(k) Two unknowns, i.e., the number of unknowns is equal to the number of newly observed satellites at the kth epoch. The equation can be solved using the common least squares method. Compared with the previous carrier phase ambiguity resolution model, the number of unknowns is reduced from s+1 to 2, greatly improving the solution efficiency.

[0042] Since the long-term output sequence of the inertial navigation module will contain drift bias, the ambiguity vector calculated in the previous step can be used to resolve the coordinates of the baseline vector again, so that the coordinates of the baseline vector are not affected by the drift error of the inertial navigation module.

[0043] Continue the solution for the k+1th epoch. Note that if the reference satellite used in the previous epoch is no longer visible in the current epoch, a new reference satellite must be switched and the integer ambiguities of the carrier phase observations initialized. To avoid frequent switching of reference satellites, a satellite close to the zenith should always be selected as the reference satellite. This is because obstructing objects or interference sources are usually located on the ground or low in the sky. Satellite signals at the zenith are less susceptible to interference and are more easily and stably observed by users. Example 2

[0044] The present disclosure provides an electronic device, which includes: a memory storing executable instructions; and a processor running the executable instructions in the memory to implement the above-mentioned GNSS carrier phase ambiguity processing method.

[0045] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0046] The memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), a hard disk, flash memory, etc.

[0047] The processor may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is configured to execute the computer-readable instructions stored in the memory.

[0048] Those skilled in the art should understand that in order to solve the technical problem of how to obtain a good user experience, this embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the scope of protection of this disclosure.

[0049] For detailed description of this embodiment, please refer to the corresponding description in the aforementioned embodiments, which will not be repeated here.

[0050] Those skilled in the art should understand that the above description of the embodiments of the present invention is only for the purpose of illustrative purposes only to illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0051] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A GNSS carrier phase ambiguity processing method, characterized in that: include: Establish a carrier phase ambiguity resolution model; Determining a vector expression for integer ambiguity in the carrier phase ambiguity resolution model; Based on the integer ambiguity of the visible satellites at the k-1th epoch and the baseline vector obtained with the aid of inertial navigation, the integer ambiguity of the continuously visible satellites at the kth epoch is calculated; The integer-cycle ambiguities of continuously visible satellites are substituted into the ambiguity resolution model to resolve the integer-cycle ambiguities of the newly visible satellites at the kth epoch, and then the integer-cycle ambiguities of all visible satellites are obtained.

2. The GNSS carrier phase ambiguity processing method according to claim 1, wherein: The carrier phase ambiguity resolution model is: E(y)=Aa+Bb, D(y)=Q yy where E(·) and D(·) represent the expectation and variance operators, respectively; y represents the column vector consisting of the difference between the carrier phase observation and the pseudorange observation and the satellite-antenna geometric distance; a represents the integer ambiguity vector, ; b represents the baseline three-dimensional vector, ; A is the coefficient matrix, which contains the carrier phase wavelength; B is the coefficient matrix, which contains the unit vector of the satellite observation direction; express A set of n-dimensional integer vectors, represents a set of three-dimensional real vectors, Q yy represents the covariance matrix of y.

3. The GNSS carrier phase ambiguity processing method according to claim 2, wherein: The vector expression of the integer ambiguity is: a=[a 12 , a 13 , a 14 ,…, a 1s ] T in, , a 1i Indicates that in satellite 1, i The carrier phase integer ambiguity in the form of double difference between ; satellite number 1 represents the reference satellite; Indicates the reference station to the satellite i The carrier phase integer ambiguity contained in the carrier phase observation; Indicates user's satellite i The carrier phase integer ambiguity contained in the carrier phase observation, i=2,3,…,s.

4. The GNSS carrier phase ambiguity processing method according to claim 3, wherein: Based on the integer ambiguity of the visible satellites at the k-1th epoch and the baseline vector obtained with inertial navigation assistance, the integer ambiguity of the continuously visible satellites at the kth epoch is calculated as follows: According to the output of the inertial navigation module on the user carrier, the change of the user antenna coordinates from the k-1th epoch to the kth epoch is calculated as the change of the baseline three-dimensional vector; Calculate the baseline three-dimensional vector of the kth epoch according to the change of the baseline three-dimensional vector; Calculate the satellite-antenna distance corresponding to each satellite based on the baseline three-dimensional vector and satellite coordinates at the kth epoch; The difference between the satellite-antenna distance and the satellite-antenna distance at the k-1th epoch is used to obtain the change in satellite-antenna distance from the k-1th epoch to the kth epoch, which is used as the carrier phase change. Calculate the carrier phase integer ambiguity of the kth epoch according to the carrier phase change; Satellite 1 to satellite s are visible at both the k-1th epoch and the kth epoch. The double-difference ambiguity vectors of the continuously visible satellites at the kth epoch are calculated.

5. The GNSS carrier phase ambiguity processing method according to claim 4, wherein: The variation of the baseline three-dimensional vector is: △u=[△x r ,△y r ,△z r ] T Among them, △u is the change of the baseline three-dimensional vector, △x r , △y r , △z r are the changes in the x, y, and z directions respectively.

6. The GNSS carrier phase ambiguity processing method according to claim 5, wherein: The baseline three-dimensional vector is: b(k)= b(k-1)+△u Among them, b(k-1) and b(k) are the three-dimensional baseline vectors of the k-1th epoch and the kth epoch respectively.

7. The GNSS carrier phase ambiguity processing method according to claim 6, wherein: The carrier phase variation is: in, Represents the carrier phase observation in double-difference form, i=2,3,…,s.

8. The GNSS carrier phase ambiguity processing method according to claim 7, wherein: The double-difference ambiguity vector of the continuously visible satellites at the kth epoch is: a 1~s (k)=[a 12 (k), a 13 (k),…, a 1s (k)] T 。 9. The GNSS carrier phase ambiguity processing method according to claim 1, wherein: Substitute the integer ambiguities of the continuously visible satellites into the ambiguity resolution model to resolve the integer ambiguities of the newly visible satellites at the kth epoch, and then obtain the integer ambiguities of all visible satellites, including: Substituting the double-difference ambiguity vector of the continuously visible satellites at the k-th epoch into the carrier phase ambiguity resolution model to obtain the carrier phase ambiguity resolution model of the k-th epoch, wherein the carrier phase ambiguity resolution model of the k-th epoch is an equation containing only the carrier phase integer ambiguities of the newly added satellites from the k-1-th epoch to the k-th epoch as unknowns; Resolve the carrier phase ambiguity resolution model for the k-th epoch.

10. An electronic device, characterized in that: The electronic device comprises: a memory storing executable instructions; A processor, wherein the processor runs the executable instructions in the memory to implement the GNSS carrier phase ambiguity processing method according to any one of claims 1 to 9.

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