A method and system for non-combined ambiguity observation to weaken carrier combination multipath

Abstract

The application provides a non-combination ambiguity observation method for weakening carrier combination multipath, relates to the field of GNSS positioning technology, and specifically comprises the following steps: obtaining carrier combination multipath to be weakened and eliminating the carrier combination multipath to obtain weakened carrier combination multipath; constructing a non-combination ambiguity estimation model based on the weakened carrier combination multipath; obtaining carrier non-combination observation values and pseudo-range observation values of double frequencies and above, and substituting the carrier non-combination observation values and the pseudo-range observation values into the non-combination ambiguity estimation model respectively to obtain a linear observation model; processing the linear observation model by using a least square method or a Kalman filtering algorithm to estimate non-combination ambiguity of which carrier combination multipath is weakened; linearly combining the non-combination ambiguity to obtain non-combination observation values of which carrier combination multipath is weakened, and completing the observation of the non-combination ambiguity. The application also provides a non-combination ambiguity observation system, so that the non-combination ambiguity no longer contains amplified carrier combination multipath, and the fixing difficulty of super-wide-lane ambiguity is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of GNSS positioning technology, in particular to a non-combination ambiguity observation method and system for weakening carrier combination multipath. BACKGROUND

[0002] Carrier non-combination observation value maximum path: the maximum path of carrier non-combination observation value can reach one fourth of its wavelength, such as GPS-L1, GPS-L2, GPS-L5, Beidou 2-B1I, Beidou 2-B3I, and Beidou-B2I, whose wavelengths are about 0.190 meters, 0.244 meters, 0.255 meters, 0.192 meters, 0.236 meters, and 0.258 meters, respectively, and their maximum multipaths are about 0.048 meters, 0.061, 0.064 meters, 0.048 meters, 0.059 meters, and 0.062 meters, respectively.

[0003] For carrier non-combination observation value of B1I with a wavelength of 0.192 meters, it is not easy to directly fix its ambiguity. In order to assist in fixing the ambiguity of B1I, a combination observation value is usually used, such as a wide lane observation value to constrain B1I. The wide lane observation value is a linear combination of carrier observation values of multiple frequency points, and its characteristic is that the wavelength of the observation value is longer, and its ambiguity is easier to be correctly fixed. Generally, a linear combination with a wavelength of about 1 meter is called a wide lane combination, and a linear combination with a wavelength of more than 2 meters is called a super wide lane combination. Generally, a carrier combination observation value L LC :

[0004]

[0005] where n represents the number of frequency points, for the i-th frequency point, L i is a carrier non-combination observation value in meters, a i is a carrier combination coefficient in meters (generally a floating point number), b i is a carrier combination coefficient in cycles (generally an integer), λ i is the wavelength of the carrier non-combination observation value, φ i is the carrier non-combination observation value in cycles, L LC is a carrier combination observation value in meters. When the combination coefficients a i , b i satisfy the following conditions:

[0006]

[0007] a carrier wide lane combination observation value L LCThe carrier combination observation value (wide lane / super wide lane combination) has a problem: although the wavelength of the wide lane observation value is lengthened so that its ambiguity is easier to be correctly searched, the combination multipath maximum value is no longer one fourth of its wavelength, but is larger. For example, for the three-frequency observation value of Beidou B1I, B3I and B2I, when the integer coefficients b1=1, b2=-5 and b3=4 are taken, the corresponding super wide lane combination coefficients a1=33.17, a2=-134.78 and a3=102.61 are obtained, and the super wide lane combination wavelength is 6.37 meters. Because the multipaths M i of the respective frequencies are independent and contained in the carrier non-combination observation value L i , when these non-combination multipaths simultaneously reach the maximum value, i.e., one fourth of the non-combination wavelength, and the signs multiplied by the coefficients are all positive or negative, an amplified super wide lane combination multipath M LC =±15.93 meters is obtained, which is much larger than the one fourth of the combination wavelength 1.59 meters. Although this is an extreme case, once it occurs, the long wavelength advantage of the super wide lane does not exist, and these amplified carrier combination multipaths will be absorbed into the super wide lane ambiguity, making it difficult to fix the super wide lane ambiguity. The multipath amplification effect of the carrier combination must be weakened so that the ambiguity estimation can truly utilize the long wavelength characteristics of the super wide lane for the non-combination ambiguity. SUMMARY

[0008] The present application provides a non-combination ambiguity observation method and system for weakening the carrier combination multipath, so that the non-combination ambiguity no longer contains the amplified carrier combination multipath, and the difficulty of fixing the super wide lane ambiguity is reduced.

[0009] To solve the above technical problems, the technical scheme of the present application is as follows:

[0010] A non-combination ambiguity observation method for weakening the carrier combination multipath, comprising the following steps:

[0011] S1: Obtain the carrier combination multipath to be weakened and eliminate it to obtain a weakened carrier combination multipath consistent with the original observation value multipath of the first frequency;

[0012] S2: Construct a non-combination ambiguity estimation model for weakening the carrier combination multipath based on the weakened carrier combination multipath;

[0013] S3: Obtain the carrier non-combination observation value and the pseudo-range observation value of two or more frequencies, and substitute them into the non-combination ambiguity estimation model to obtain a linear observation model;

[0014] S4: The linear observation model is processed using the least squares method or Kalman filtering algorithm to estimate the non-combination ambiguity that reduces the carrier combination multipath.

[0015] S5: Linearly combine the uncombined ambiguities to obtain uncombined observations that weaken carrier-combined multipaths, thus completing the observation of uncombined ambiguities.

[0016] In the above scheme, by constructing a non-combined ambiguity estimation model, the non-combined ambiguity no longer includes amplified carrier combination multipath, effectively reducing the difficulty of fixing ultra-wide lane ambiguity.

[0017] Specifically, step S1 is as follows:

[0018] Let the non-combined inter-station single-difference carrier observation value at the i-th frequency point be expressed in meters:

[0019]

[0020] in ρ is the inter-satellite single difference operator, Δ is the inter-station single difference operator, ρ is the satellite-to-Earth distance, c is the speed of light, and dt is the inter-satellite single difference operator. r It is the receiver clock bias, dt s It is the satellite clock bias, T is the tropospheric delay, and I is the satellite clock bias. i λ is the ionospheric delay at the i-th frequency point. i N is the carrier wavelength at the i-th frequency point. i M is the carrier ambiguity at the i-th frequency point. i It is the carrier multipath at the i-th frequency point, ∈ i This is the carrier noise at the i-th frequency point; for carrier observations with dual or higher frequencies, take the uncombined carrier observations at the i and j-th frequencies and perform an inter-frequency single difference, where i ≠ j; this eliminates all frequency-independent quantities with the same sign, resulting in:

[0021]

[0022] This is due to the spatial correlation characteristics of ionospheric delay. The changes are slow and the values ​​are small, so they are considered constants within a certain time window; when the carrier observation does not experience cycle slips, the ambiguity... These are constants; if these constant terms can be determined, inter-frequency single-difference-double-difference carrier multipath... It can then be observed; for carrier combinations using n frequency points, the multipath of the combination is weakened; the wide-lane combination coefficient a is known. i sum Then we have:

[0023]

[0024] in is carrier combination observation value, is carrier combination multipath, both of which are observable, thus, as long as the term is eliminated, the carrier combination multipath is weakened to 1 times that is, consistent with the first frequency point original observation value multipath.

[0025] The step S2 is specifically:

[0026] Suppose the parameter vector X of the observation model, the observation coefficient matrix is H, and the observation value vector is Z. Considering the ionospheric residual error of the medium-long baseline mode The numerical value is large, and the general expression of the non-combination ambiguity estimation model is obtained:

[0027]

[0028]

[0029] Among them, for the i-th frequency point, p i is the pseudo-range observation value, a 1i，k is the k-th coefficient of the wide-lane combination of the 1st and i-th frequency points, i≠j and k=1,2; f i is the frequency of the carrier observation value, is the non-combination ambiguity; c i is used to generate the combination coefficient of the first frequency point first-order ionospheric virtual observation .

[0030] Among them, in the step S3, the carrier non-combination observation value and the pseudo-range observation value of double frequency and above are obtained, and the pseudo-range observation value is substituted into the non-combination ambiguity estimation model to generate The carrier non-combination observation value is substituted into the non-combination ambiguity estimation model to generate The construction method of the coefficient is specifically:

[0031]

[0032] Further, a linear observation model is obtained.

[0033] Among them, in the step S4, the process of processing the linear observation model by using the least square method is specifically:

[0034] Suppose P is the observation value weight matrix, and the top mark represents the estimated value, and has:

[0035]

[0036] At this point, the non-combination ambiguity which weakens the carrier combination multipath is estimated.And in step S5, the non-combination ambiguity is linearly combined to obtain the combined observation value weakened by the carrier combination multipath; wherein, the superscript - represents weakening the carrier combination multipath, for the i-th frequency point, b i is the integer combination coefficient, λ i is the wavelength, and has:

[0037]

[0038] At this point, the combined observation value weakened by the carrier combination multipath is obtained, and the ambiguity no longer contains the carrier combination multipath that is amplified.

[0039] The scheme also provides a non-combination ambiguity observation system for weakening the carrier combination multipath, for realizing a non-combination ambiguity observation method for weakening the carrier combination multipath, and specifically includes a carrier combination multipath acquisition and elimination module, a non-combination ambiguity estimation model construction module, a linear observation model calculation module, a non-combination ambiguity estimation module, and a linear combination module; wherein:

[0040] The carrier combination multipath acquisition and elimination module is used to acquire the carrier combination multipath that can be weakened and eliminate it to obtain the carrier combination multipath weakened in the same way as the original observation value multipath of the first frequency point;

[0041] The non-combination ambiguity estimation model construction module constructs a non-combination ambiguity estimation model for weakening the carrier combination multipath based on the carrier combination multipath that is weakened;

[0042] The linear observation model calculation module is used to acquire the carrier non-combination observation value and the pseudo-range observation value of double frequency and above and substitute them into the non-combination ambiguity estimation model, respectively, to obtain a linear observation model;

[0043] The non-combination ambiguity estimation module uses the least square method or the Kalman filtering algorithm to process the linear observation model to estimate the non-combination ambiguity weakened by the carrier combination multipath;

[0044] The linear combination module is used to linearly combine the non-combination ambiguity to obtain the non-combination observation value weakened by the carrier combination multipath, and complete the observation of the non-combination ambiguity.

[0045] In the carrier combination multipath acquisition and elimination module, the following steps are specifically executed:

[0046] Let the non-combination inter-station single-difference carrier observation value of the i-th frequency point in meters be:

[0047]

[0048] wherein is the inter-satellite single-difference operator, Δ is the inter-station single-difference operator, ρ is the geodetic distance, c is the speed of light, dt r is the receiver clock error, dt s is the satellite clock error, T is the tropospheric delay, I i is the ionospheric delay of the ith frequency, λ i is the carrier wavelength of the ith frequency, N i is the carrier ambiguity of the ith frequency, M i is the carrier multipath of the ith frequency, ∈ i is the carrier noise of the ith frequency; for dual-frequency and above, the non-combined carrier observations of the ith and jth frequencies are taken as inter-frequency single-difference, where i≠j; thus, all the quantities that are frequency-independent and have the same sign are eliminated, and the following is obtained:

[0049]

[0050] where, because of the spatial correlation of the ionospheric delay, it changes slowly and has a small value, and it is regarded as a constant term within a certain time window; when the carrier observations do not have cycle slips, the ambiguity is constant; if these constant terms can be determined, the inter-frequency-dual-difference carrier multipath can be observed; for carrier combinations using n frequencies, the multipath of the combination is weakened; the sum of the wide-lane combination coefficients a i is known , and the following is obtained:

[0051]

[0052] where is the carrier combination observation, is the carrier combination multipath, both of which are observable, and thus, as long as the term is eliminated, the carrier combination multipath is weakened to 1 times , that is, the same as the multipath of the original observation of the first frequency.

[0053] In the non-combined ambiguity estimation model construction module, the following steps are specifically performed:

[0054] Let the parameter vector of the observation model be X, the observation coefficient matrix be H, and the observation value vector be Z; considering that the ionospheric residual error of the medium-long baseline mode is large in value, the general expression of the non-combined ambiguity estimation model is obtained:

[0055]

[0056] ​

[0057] wherein for the ith frequency point, p i is the pseudo-range observation value, a 1i，k is the kth coefficient of the wide-lane combination of the 1st and ith frequency points, i≠j and k=1, 2; f i is the frequency of the carrier observation value, is the non-combined ambiguity; C i a combination coefficient for generating a first-order ionospheric virtual observation of the first frequency point.

[0058] wherein in the linear observation model calculation module, the carrier non-combined observation value and the pseudo-range observation value of double frequency and above are obtained, the pseudo-range observation value is substituted into the non-combined ambiguity estimation model to generate the carrier non-combined observation value is substituted into the non-combined ambiguity estimation model to generate the construction mode of the coefficient is specifically as follows:

[0059]

[0060] a linear observation model is further obtained.

[0061] wherein the process of processing the linear observation model by the least square method in the non-combined ambiguity estimation module is specifically as follows:

[0062] wherein P is an observation value weight matrix, the top mark represents an estimated value, and there is:

[0063]

[0064] At this point, the non-combined ambiguity that weakens the carrier combined multipath is estimated and in the linear combination module, the non-combined ambiguity is linearly combined to obtain the combined observation value that weakens the carrier combined multipath; wherein the top mark represents that the carrier combined multipath is weakened, for the ith frequency point, b i is an integer combination coefficient, λ i is a wavelength, and there is:

[0065]

[0066] At this point, the combined observation value that weakens the carrier combined multipath is obtained, and the ambiguity no longer contains the carrier combined multipath that is amplified.

[0067] Compared with the prior art, the beneficial effects of the technical scheme of the present application are:

[0068] ​This invention proposes a non-combination ambiguity observation method and system to reduce carrier-combined multipath. By constructing a non-combination ambiguity estimation model, the non-combination ambiguity no longer includes amplified carrier-combined multipath, effectively reducing the difficulty of fixing ultra-wide lane ambiguity. Attached Figure Description

[0069] Figure 1 This is a flowchart illustrating the non-combined ambiguity observation method for reducing carrier-combined multipath in this invention.

[0070] Figure 2 This is a schematic diagram of the module connections of the non-combined ambiguity observation system for reducing carrier-combined multipath in this invention;

[0071] Figure 3 This is a flowchart illustrating a non-combined ambiguity observation method implemented through a non-combined ambiguity observation system in one embodiment of the present invention. Detailed Implementation

[0072] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0073] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;

[0074] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0075] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0076] Example 1

[0077] like Figure 1 As shown, this scheme specifically provides a non-combined ambiguity observation method to reduce carrier-combined multipath ambiguity, including the following steps:

[0078] S1: Obtain the carrier combination multipath that can be weakened and eliminate it to obtain the weakened carrier combination multipath that is consistent with the original observation multipath of the first frequency point.

[0079] S2: Construct a non-combined ambiguity estimation model for weakened carrier-combined multipath based on weakened carrier-combined multipath;

[0080] S3: Obtain uncombined carrier observations and pseudorange observations for dual-frequency or higher carriers, and substitute them into the uncombined ambiguity estimation model to obtain a linear observation model;

[0081] S4: The linear observation model is processed using the least squares method or Kalman filtering algorithm to estimate the non-combination ambiguity that reduces the carrier combination multipath.

[0082] S5: linearly combining the non-combination ambiguities to obtain non-combination observations weakened by carrier combination multipath, and completing observation of the non-combination ambiguities.

[0083] In the specific implementation process, by constructing a non-combination ambiguity estimation model, the non-combination ambiguities no longer contain amplified carrier combination multipath, and the fixing difficulty of the super-wide lane ambiguities is effectively reduced.

[0084] More specifically, the step S1 is specifically:

[0085] Let the non-combination inter-station single-difference carrier observation value of the i th frequency point be:

[0086]

[0087] Among them is an inter-satellite single-difference operator, Δ is an inter-station single-difference operator, ρ is a satellite-geodetic distance, c is a light speed, dt r is a receiver clock error, dt s is a satellite clock error, T is a troposphere delay, I i is the ionospheric delay of the i th frequency point, λ i is the carrier wavelength of the i th frequency point, N i is the carrier ambiguity of the i th frequency point, M i is the carrier multipath of the i th frequency point, ∈ i is the carrier noise of the i th frequency point; for double-frequency and above carrier observations, the carrier non-combination observations of the i th and j th frequency points are taken as inter-frequency single-difference, where i≠j; in this way, all the quantities independent of frequency and with the same sign are eliminated, and the following is obtained:

[0088]

[0089] Among them, because of the characteristics of the spatial correlation of the ionospheric delay, it changes slowly and has a small value, and it is regarded as a constant term within a certain time window; when the carrier observations do not have a cycle slip, the ambiguity is a constant; if these constant terms can be determined, the inter-frequency double-difference carrier multipath can be observed; for carrier combination using n frequency points, the combined multipath is weakened; given the sum of the wide lane combination coefficients a i , then:

[0090]

[0091] Among them is the carrier combination observation value, is the carrier combination multipath, both of which are observable, so as long as the​ If the carrier combination multipath is weakened to 1 times, the item is removed. That is, consistent with the first frequency point original observation value multipath.

[0092] More specifically, the step S2 is specifically:

[0093] Suppose the parameter vector X of the observation model, the observation coefficient matrix is H, and the observation value vector is Z. Considering the ionospheric residual error of the medium-long baseline mode The numerical value is large, and the general expression of the non-combination ambiguity estimation model is obtained:

[0094]

[0095]

[0096] Wherein, for the i-th frequency point, p i is the pseudo-range observation value, a 1i，k is the first and i-th frequency point wide lane combination k-th coefficient, i≠j and k=1,2; f i is the frequency of the carrier observation value, is the non-combination ambiguity; c i The combination coefficient for generating the first frequency point first-order ionospheric virtual observation .

[0097] More specifically, in the step S3, the double-frequency and above carrier non-combination observation value and pseudo-range observation value are obtained, and the pseudo-range observation value is substituted into the non-combination ambiguity estimation model to generate The carrier non-combination observation value is substituted into the non-combination ambiguity estimation model to generate The construction method of the coefficient is specifically:

[0098]

[0099] Further, the linear observation model is obtained.

[0100] More specifically, in the step S4, the process of processing the linear observation model by using the least square method is specifically:

[0101] Suppose P is the observation value weight matrix, and ^ represents the estimated value. There is:

[0102]

[0103] At this point, the non-combination ambiguity weakened by the carrier combination multipath is estimated And in step S5, the non-combination ambiguity is linearly combined to obtain the combination observation value weakened by the carrier combination multipath; wherein, the top mark- represents the carrier combination multipath, and for the i-th frequency point, b iis the integer combination coefficient, λ i is the wavelength, and has:

[0104]

[0105] Thus, the combined observations weakened by the carrier combination multipath are obtained, and the ambiguities no longer contain the carrier combination multipath that is amplified.

[0106] In the embodiment, if it is a short baseline mode, the second row of the deletion parameter vector X the second column of the deletion coefficient matrix H and the corresponding observation value row are deleted. and the second column of the deletion coefficient matrix H and the corresponding observation value row are deleted.

[0107] Embodiment 2

[0108] More specifically, on the basis of Embodiment 1, the scheme further provides a non-combination ambiguity observation system for weakening carrier combination multipath, for implementing a non-combination ambiguity observation method for weakening carrier combination multipath, a schematic diagram of which is shown in Figure 2 as shown, and specifically includes a carrier combination multipath acquisition and elimination module, a non-combination ambiguity estimation model construction module, a linear observation model calculation module, a non-combination ambiguity estimation module, and a linear combination module; wherein:

[0109] The carrier combination multipath acquisition and elimination module is configured to acquire carrier combination multipaths that can be weakened and eliminate them, to obtain carrier combination multipaths that are consistent with the original observation multipaths of the first frequency point after weakening.

[0110] The non-combination ambiguity estimation model construction module is configured to construct a non-combination ambiguity estimation model for weakening carrier combination multipaths based on the weakened carrier combination multipaths.

[0111] The linear observation model calculation module is configured to acquire double-frequency and above carrier non-combination observations and pseudo-range observations and substitute them into the non-combination ambiguity estimation model respectively, to obtain a linear observation model.

[0112] The non-combination ambiguity estimation module is configured to use a least square method or a Kalman filtering algorithm to process the linear observation model, to estimate non-combination ambiguities that are weakened by carrier combination multipaths.

[0113] The linear combination module is configured to linearly combine the non-combination ambiguities, to obtain non-combination observations that are weakened by carrier combination multipaths, to complete the observation of non-combination ambiguities.

[0114] More specifically, in the carrier combination multipath acquisition and elimination module, the following steps are specifically executed:

[0115] The non-combined inter-station single-difference carrier observation value of the i-th frequency point is recorded as:

[0116]

[0117] Wherein is an inter-satellite single-difference operator, Δ is an inter-station single-difference operator, ρ is a satellite-geodetic distance, c is a light speed, dt r is a receiver clock error, dt s is a satellite clock error, T is a troposphere delay, I i is an ionosphere delay of the i-th frequency point, λ i is a carrier wavelength of the i-th frequency point, N i is a carrier ambiguity of the i-th frequency point, M i is a carrier multipath of the i-th frequency point, ∈ i is a carrier noise of the i-th frequency point; for double-frequency and above carrier observations, the non-combined carrier observations of the i-th and j-th frequency points are taken as inter-frequency single-difference, wherein i≠j; thus, all the frequency-independent and sign-same quantities are eliminated, and the following is obtained:

[0118]

[0119] Wherein because of the characteristics of the spatial correlation of the ionosphere delay, it changes slowly and has a small value, and it is regarded as a constant term within a certain time window; when the carrier observation value does not have a cycle slip, the ambiguity is constant; if these constant terms can be determined, the inter-frequency single-difference-double-difference carrier multipath can be observed; for a carrier combination using n frequency points, the multipath of the combination is weakened; the sum of the wide-lane combination coefficients a i is known , and the following is obtained:

[0120]

[0121] Wherein is a carrier combination observation value, is a carrier combination multipath, both of which are observable, thus, as long as the term is eliminated, the carrier combination multipath is weakened to 1 times , that is, consistent with the original observation multipath of the first frequency point.

[0122] More specifically, in the non-combined ambiguity estimation model construction module, the following steps are specifically performed:

[0123] Suppose that the parameter vector X of the observation model, the observation coefficient matrix H, and the observation value vector Z are considered, and the ionosphere residual error of the medium-long baseline mode is considered The larger the value is, the more general expression of the non-combination ambiguity estimation model is obtained:

[0124]

[0125]

[0126] wherein for the i-th frequency point, p i is the pseudo-range observation value, a 1i，k is the 1st and i-th frequency point wide-lane combination k-th coefficient, i≠j and k=1, 2; f i is the frequency of the carrier observation value, is the non-combination ambiguity; c i is used to generate the first-order ionosphere virtual observation value of the first frequency point. The combination coefficient.

[0127] More specifically, in the linear observation model calculation module, the double-frequency and above carrier non-combination observation value and the pseudo-range observation value are obtained, the pseudo-range observation value is substituted into the non-combination ambiguity estimation model to generate The carrier non-combination observation value is substituted into the non-combination ambiguity estimation model to generate The construction mode of the coefficient is specifically as follows:

[0128]

[0129] Further, the linear observation model is obtained.

[0130] More specifically, the process of using the least square method to process the linear observation model in the non-combination ambiguity estimation module is specifically as follows:

[0131] Let P be the observation value weight matrix, and ^top mark represents the estimated value, and has:

[0132]

[0133] At this point, the non-combination ambiguity that weakens the carrier combination multipath is estimated And in the linear combination module, the non-combination ambiguity is linearly combined to obtain the combination observation value that weakens the carrier combination multipath; wherein, the top mark- represents that the carrier combination multipath is weakened, for the i-th frequency point, b i is the integer combination coefficient, λ i is the wavelength, and has:

[0134]

[0135] At this point, the combination observation value that weakens the carrier combination multipath is obtained, and the ambiguity no longer contains the carrier combination multipath that is amplified.

[0136] Embodiment 3

[0137] In the embodiment, the technical process that a non-combination ambiguity observation method of weakening carrier combination multipath is applied to a non-combination ambiguity observation system of weakening carrier combination multipath is specifically illustrated, and the embodiment is specifically as shown in Figure 3

[0138] Each step in the non-combination ambiguity observation method is coded, edited into a software module corresponding to the corresponding function, and stored in the non-combination ambiguity observation system. The non-combination ambiguity observation system has a corresponding memory and a controller, which can sequentially call the software modules stored in the memory according to the process steps of the non-combination ambiguity observation method, automatically realize the technical implementation process of the non-combination ambiguity observation method, and only need to input the corresponding parameters into the system when applied. The non-combination ambiguity obtained by calculation no longer contains amplified carrier combination multipath, effectively reducing the fixing difficulty of ultra-wide lane ambiguity.

[0139] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, those skilled in the art can make other different forms of changes or modifications. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.​

Claims

1. A method for reducing uncombined ambiguity in carrier-combined multipath observations, characterized in that, Includes the following steps: S1: Obtain and eliminate carrier combination multipaths that can be weakened, resulting in weakened carrier combination multipaths consistent with the original observation multipaths at the first frequency point. Specifically: Recorded in meters The non-combined inter-station single-difference carrier observation values ​​for each frequency point are: in It is an interstellar single difference operator. It is an inter-station single difference operator. It is the distance between the two places. It's the speed of light. It is the receiver clock bias. It's satellite clock bias. It is a tropospheric delay. It is the first Ionospheric delay at each frequency point It is the first Carrier wavelength at each frequency point It is the first Carrier ambiguity at each frequency point It is the first Carrier multipath at a frequency point It is the first Carrier noise at each frequency point; for dual-frequency or higher carrier observations, take the nth one. The carrier non-combined observations at a frequency point are used to perform inter-frequency single differences, where This eliminates all quantities that are independent of frequency and have the same sign, resulting in: This is due to the spatial correlation characteristics of ionospheric delay. The changes are slow and the values ​​are small, so they are considered constants within a certain time window; when the carrier observation does not experience cycle slips, the ambiguity... These are constants; if these constant terms can be determined, inter-frequency single-difference-double-difference carrier multipath... It can then be observed; for those who used Carrier combinations at various frequencies are used to weaken the multipath of these combinations; the wide-lane combination coefficients are known. sum Then we have: in These are carrier combination observations. It is a carrier-combined multipath, and both are observable; therefore, as long as it is eliminated... If this is the case, then the carrier combination multipath is reduced to half. That is, it is consistent with the multipath of the original observation value of the first frequency point; S2: Construct a non-combined ambiguity estimation model for weakened carrier-combined multipath based on the weakened carrier-combined multipath, specifically: Let the parameter vector of the observation model be... The observation coefficient matrix is The observation vector is Considering the first-order virtual observation of the ionosphere at the i-th frequency point With larger numerical values, the general expression for the non-combined ambiguity estimation model is obtained: For the first One frequency point, These are pseudorange observations. It is the first and The wide-lane combination of frequency points One coefficient, and ; It is the frequency of the carrier observation. Yes / no combination ambiguity; First-order virtual ionospheric observations used to generate the first frequency point The combination coefficients; S3: Obtain uncombined carrier observations and pseudorange observations for dual-frequency or higher carriers, and substitute them into the uncombined ambiguity estimation model to obtain a linear observation model; S4: The linear observation model is processed using the least squares method or Kalman filtering algorithm to estimate the non-combination ambiguity that reduces the carrier combination multipath. S5: Linearly combine the uncombined ambiguities to obtain combined observations that weaken the carrier-combined multipath, thus completing the observation of the uncombined ambiguities.

2. The non-combined ambiguity observation method for reducing carrier-combined multipath ambiguity according to claim 1, characterized in that, In step S3, uncombined carrier observations and pseudorange observations of dual-frequency or higher carriers are obtained, and the pseudorange observations are substituted into the uncombined ambiguity estimation model to generate... Substituting the carrier non-combined observations into the non-combined ambiguity estimation model generates The coefficients are constructed as follows: A linear observation model was then obtained.

3. The non-combined ambiguity observation method for reducing carrier-combined multipath as described in claim 2, characterized in that, In step S4, the process of processing the linear observation model using the least squares method is as follows: set up It is the observation weight matrix. The superscript indicates the estimated value, and we have: Thus, the non-combination ambiguity that weakens carrier-combined multipath was estimated. In step S5, a linear combination of the non-combined ambiguities is performed to obtain combined observations that weaken the carrier-combined multipath; wherein, the top label is denoted as... This indicates weakened carrier combination multipath, for the first... One frequency point, These are integer combination coefficients. It is the wavelength, and we have: Thus, we obtain the combined observations with reduced carrier-combined multipath, whose ambiguity no longer includes the amplified carrier-combined multipath.

4. A non-combined ambiguity observation system for reducing carrier-combined multipath ambiguity, characterized in that, It includes a carrier-combined multipath acquisition and cancellation module, a non-combined ambiguity estimation model construction module, a linear observation model calculation module, a non-combined ambiguity estimation module, and a linear combination module; wherein: The carrier combination multipath acquisition and elimination module is used to acquire carrier combination multipaths that can be weakened and eliminate them to obtain weakened carrier combination multipaths that are consistent with the original observation multipaths at the first frequency point. In the carrier combination multipath acquisition and cancellation module, the following steps are specifically performed: Recorded in meters The non-combined inter-station single-difference carrier observation values ​​for each frequency point are: in It is an interstellar single difference operator. It is an inter-station single difference operator. It is the distance between the two places. It's the speed of light. It is the receiver clock bias. It's satellite clock bias. It is a tropospheric delay. It is the first Ionospheric delay at each frequency point It is the first Carrier wavelength at each frequency point It is the first Carrier ambiguity at each frequency point It is the first Carrier multipath at a frequency point It is the first Carrier noise at each frequency point; for dual-frequency or higher carrier observations, take the nth one. The carrier non-combined observations at a frequency point are used to perform inter-frequency single differences, where This eliminates all quantities that are independent of frequency and have the same sign, resulting in: This is due to the spatial correlation characteristics of ionospheric delay. The changes are slow and the values ​​are small, so they are considered constants within a certain time window; when the carrier observation does not experience cycle slips, the ambiguity... These are constants; if these constant terms can be determined, inter-frequency single-difference-double-difference carrier multipath... It can then be observed; for those who used Carrier combinations at various frequencies are used to weaken the multipath of these combinations; the wide-lane combination coefficients are known. sum Then we have: in These are carrier combination observations. It is a carrier-combined multipath, and both are observable; therefore, as long as it is eliminated... If this is the case, then the carrier combination multipath is reduced to half. That is, it is consistent with the multipath of the original observation value of the first frequency point; The non-combined ambiguity estimation model construction module constructs a weakened carrier-combined multipath non-combined ambiguity estimation model based on the weakened carrier-combined multipath; the non-combined ambiguity estimation model construction module specifically performs the following steps: Let the parameter vector of the observation model be... The observation coefficient matrix is The observation vector is Considering the first-order virtual observation of the ionosphere at the i-th frequency point With larger numerical values, the general expression for the non-combined ambiguity estimation model is obtained: For the first One frequency point, These are pseudorange observations. It is the first and The wide-lane combination of frequency points One coefficient, and ; It is the frequency of the carrier observation. Yes / no combination ambiguity; First-order virtual ionospheric observations used to generate the first frequency point The combination coefficients; The linear observation model calculation module is used to obtain the uncombined carrier observations and pseudorange observations of dual-frequency and above carriers and substitute them into the uncombined ambiguity estimation model to obtain the linear observation model. The non-combined ambiguity estimation module uses the least squares method or Kalman filter algorithm to process the linear observation model and estimate the non-combined ambiguity that weakens the carrier combination multipath. The linear combination module is used to linearly combine the uncombined ambiguities to obtain combined observations that weaken the carrier combination multipath, thus completing the observation of the uncombined ambiguities.

5. A non-combined ambiguity observation system for reducing carrier-combined multipath ambiguity according to claim 4, characterized in that, In the linear observation model calculation module, uncombined carrier observations and pseudorange observations of dual frequencies or higher are obtained, and the pseudorange observations are substituted into the uncombined ambiguity estimation model to generate... Substituting the carrier non-combined observations into the non-combined ambiguity estimation model generates The coefficients are constructed as follows: A linear observation model was then obtained.

6. A non-combined ambiguity observation system for reducing carrier-combined multipath ambiguity according to claim 5, characterized in that, The process of using the least squares method to process the linear observation model in the non-combined ambiguity estimation module is as follows: set up It is the observation weight matrix. The superscript indicates the estimated value, and we have: Thus, the non-combination ambiguity that weakens carrier-combined multipath was estimated. In the linear combination module, non-combined ambiguities are linearly combined to obtain combined observations that weaken carrier-combined multipaths; where, the top index is denoted... This indicates weakened carrier combination multipath, for the first... One frequency point, These are integer combination coefficients. It is the wavelength, and we have: Thus, we obtain the combined observations with reduced carrier-combined multipath, whose ambiguity no longer includes the amplified carrier-combined multipath.

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