Method and apparatus for adaptive carrier phase smoothing pseudorange

Abstract

This application discloses an adaptive carrier phase smoothing pseudorange method and apparatus, which smooths the pseudorange of all frequency points in a simple and practical way. As long as there is a continuous carrier without cycle slip at any frequency point, pseudorange smoothing can continue without resetting the filter, so that the pseudorange before and after the positioning frequency point switching is smoothed, improving the smoothing accuracy. Furthermore, using a carrier of any frequency point to smooth the pseudorange of all frequency points reduces the large error caused by the positioning frequency point switching.

Description

Technical Field

[0001] This application relates to, but is not limited to, satellite navigation technology, and in particular to a method and apparatus for adaptive carrier phase smoothing pseudorange. Background Technology

[0002] In Global Navigation Satellite System (GNSS) technology, the receiver's position is determined by measuring pseudorange or carrier phase observations between the satellite and the user receiver antenna, subtracting measurement errors from the satellite, receiver, and propagation path during the observation process, and using range intersection. The accuracy of this calculation is closely related to the quality of the observations. Due to systematic or random errors, pseudorange multipath errors and observation noise are much greater than carrier phase observation noise. Furthermore, carrier phase suffers from integer ambiguity and cycle slip problems. Therefore, utilizing the complementary characteristics of both to reduce pseudorange observation errors is an effective means of improving positioning accuracy.

[0003] Among related technologies, widely used Hatch filtering carrier smoothing pseudorange methods include single-frequency carrier phase smoothing pseudorange and dual-frequency carrier phase smoothing pseudorange. The single-frequency carrier phase smoothing pseudorange method introduces ionospheric divergence errors that accumulate over time, having a significant impact during periods of ionospheric activity. Although the filter is reset after a period of smoothing, the setting of the smoothing constant is highly arbitrary, and frequent resets can negatively affect the smoothing effect. The dual-frequency carrier phase smoothing pseudorange method eliminates the influence of ionospheric delay errors and is not limited by the smoothing constant. However, its application requires ensuring the continuity of the carrier signals at both frequencies. When a carrier cycle slips at either selected frequency, related technologies typically either directly reset the filter or use Doppler frequency shift to assist carrier phase smoothing pseudorange. However, directly resetting the filter causes temporary failure of pseudorange smoothing, and frequent reset operations reduce the suppression of multipath and measurement noise. Using Doppler frequency shift instead of carrier smoothing pseudorange results in significant Doppler measurement noise, leading to lower smoothing accuracy.

[0004] In related technologies, carriers at a certain frequency can only smooth the pseudorange of their corresponding frequency. This carrier-smoothed pseudorange mode cannot use a set of effective carriers to smooth the pseudorange of all frequencies, making it inflexible in application and potentially leading to larger errors when switching positioning frequencies. Summary of the Invention

[0005] This application provides a method and apparatus for adaptive carrier phase smoothing pseudorange, which can improve smoothing accuracy.

[0006] This invention provides a method for adaptive carrier phase smoothing pseudorange, comprising:

[0007] If the number of frequency points that have not experienced cycle slips in the current epoch satisfies the pseudorange smoothing condition, select one or more frequency point carriers corresponding to the pseudorange smoothing condition from the carriers without cycle slips.

[0008] The pseudorange of the current epoch frequency is smoothed based on the smoothed pseudorange observations of the previous epoch and the inter-epoch carrier increments of one or more selected frequency points.

[0009] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the adaptive carrier phase smoothing pseudorange method described in any of the preceding embodiments.

[0010] This application provides an adaptive carrier phase smoothing pseudorange device, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the adaptive carrier phase smoothing pseudorange method described in any of the above claims.

[0011] This application embodiment further provides an adaptive carrier phase smoothing pseudorange device, including: a judgment module and a smoothing module, wherein,

[0012] The judgment module is used to select one or more frequency carriers corresponding to the pseudorange smoothing condition from the carriers without cycle slips if the number of frequency points that have not experienced cycle slips in the current epoch meets the pseudorange smoothing condition.

[0013] The smoothing module is used to smooth the pseudorange of the current epoch frequency point based on the smoothed pseudorange observation value of the previous epoch and the inter-epoch carrier increment of one or more selected frequency points.

[0014] The adaptive carrier phase smoothing pseudorange method provided in this application provides a simple and practical way to smooth the pseudorange of all frequency points. As long as there is a continuous carrier without cycle slip at any frequency point, pseudorange smoothing can continue without resetting the filter. This ensures that the pseudorange before and after the positioning frequency point switching is smoothed, improving the smoothing accuracy. Furthermore, by using a carrier of any frequency point to smooth the pseudorange of all frequency points, the large error caused by the positioning frequency point switching is reduced.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0016] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0017] Figure 1 This is a flowchart illustrating the adaptive carrier phase smoothing pseudorange method in the embodiments of this application;

[0018] Figure 2 This is a flowchart illustrating an embodiment of the adaptive single-frequency carrier phase smoothing pseudorange method in this application.

[0019] Figure 3 This is a flowchart illustrating an embodiment of the adaptive dual-frequency carrier phase smoothing pseudorange method in this application.

[0020] Figure 4 This is a schematic diagram of the structure of the adaptive carrier phase smoothing pseudorange device in the embodiments of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0022] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0024] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0026] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0027] Figure 1 This is a flowchart illustrating the adaptive carrier phase smoothing pseudorange method in an embodiment of this application, as shown below. Figure 1 As shown, it includes:

[0028] Step 100: If the number of frequency points that have not experienced cycle slips in the current epoch meets the pseudorange smoothing condition, select one or more frequency point carriers corresponding to the pseudorange smoothing condition from the carriers without cycle slips.

[0029] In one exemplary instance, step 100 may also include:

[0030] Cycle slip detection is performed on the carrier phase of all frequency points to determine whether a cycle slip has occurred at each frequency point, and the number of carrier frequency points that have not experienced a cycle slip in the current epoch is counted. In this way, m carrier frequency points that have not experienced a cycle slip in the current epoch are selected as valid carrier frequency points.

[0031] In one exemplary instance, when applying the adaptive carrier phase smoothing pseudorange method to the case of single-frequency carrier phase smoothing pseudorange, the pseudorange smoothing condition may include: the number m of frequency points without cycle slips is greater than or equal to 1. Accordingly, the number m of frequency points without cycle slips in step 100 satisfies the pseudorange smoothing condition, which includes: the number m of frequency points without cycle slips is greater than or equal to 1. That is, pseudorange smoothing can be performed as long as there is a cycle-slip-free carrier at any given frequency.

[0032] In one exemplary instance, when the adaptive carrier phase smoothing pseudorange method is applied to the case of single-frequency carrier phase smoothing pseudorange, step 100, which involves selecting one or more frequency carriers corresponding to the pseudorange smoothing condition from cycle-slip-free carriers, may include:

[0033] From the current epoch of m cycle-slip-free carriers, arbitrarily select one frequency carrier as the frequency carrier for pseudorange smoothing; or,

[0034] Select the ionospheric mapping factor γ from the m cycle-slip-free carriers of the current epoch. j The smallest frequency point (i.e., the optimal carrier frequency point) is used as the carrier frequency point for pseudorange smoothing, where, Where f1 represents the signal frequency at frequency point 1, fj This indicates the signal frequency at the currently selected frequency point j.

[0035] In one exemplary instance, when applying the adaptive carrier phase smoothing pseudorange method to the case of dual-frequency carrier phase smoothing pseudorange, the pseudorange smoothing condition may include: the number of frequency points m without cycle slips is greater than or equal to 2. Accordingly, the number of frequency points m without cycle slips in step 100 satisfies the pseudorange smoothing condition, which includes: the number of frequency points m without cycle slips is greater than or equal to 2. That is, pseudorange smoothing can be performed as long as there are any two cycle-slip-free carriers at any two frequencies.

[0036] In one exemplary instance, when the adaptive carrier phase smoothing pseudorange method is applied to the case of dual-frequency carrier phase smoothing pseudorange, step 100, which involves selecting one or more frequency carriers corresponding to the pseudorange smoothing condition from the cycle-slip-free carriers, may include:

[0037] When the number of frequency points without cycle slips is m=2, the m frequency points without cycle slips are directly selected as the two frequency point carriers for pseudorange smoothing; when the number of frequency points without cycle slips is m>2, two frequency point carriers can be arbitrarily selected from the m frequency points without cycle slips as the frequency point carriers for pseudorange smoothing.

[0038] Step 101: Smooth the pseudorange of the current epoch frequency point based on the smoothed pseudorange observation value of the previous epoch and the inter-epoch carrier increment of one or more selected frequency points.

[0039] The frequency points selected in this step refer to the frequency points selected in the current epoch, not the carrier frequency points selected in the previous epoch. In one embodiment, for a single-frequency carrier smoothing pseudorange scenario, only one frequency point needs to be selected; for a dual-frequency carrier smoothing pseudorange scenario, two frequency points need to be selected.

[0040] In one exemplary instance, the epoch-time carrier increment of one or more selected frequencies can be used to smooth the pseudorange of all frequencies in the current epoch. In another exemplary instance, the epoch-time carrier increment of one or more selected frequencies can be used to smooth the pseudorange of any frequency in the current epoch. That is, the embodiments of this application are not limited to smoothing the pseudorange of a certain frequency carrier only for its corresponding frequency. In one embodiment, for a single-frequency carrier pseudorange smoothing scenario, only one valid carrier frequency needs to be selected to flexibly smooth the pseudorange of any frequency. In one embodiment, for a dual-frequency carrier pseudorange smoothing scenario, only two valid carrier frequencies need to be selected to flexibly smooth the pseudorange of any frequency.

[0041] In one exemplary instance, for the case where the adaptive carrier phase smoothing pseudorange method is applied to single-frequency carrier phase smoothing pseudorange, step 101 may include:

[0042] Substitute the selected carrier frequency into formula (1), and smooth the pseudorange of all frequency points in the current epoch one by one. In formula (1), k represents the current epoch, and (k-1) represents the previous epoch.

[0043]

[0044] In formula (1), Let i represent the smoothed pseudorange observations at epoch k and epoch (k-1) of frequency point i, respectively. This represents the raw pseudorange observation value at epoch k of frequency point i. This represents the interepoch carrier increment at frequency point j. The change in ionospheric delay between epochs can be calculated using ionospheric delay information from a Satellite-Based Augmentation System (SBAS) or using an ionospheric error model broadcast by GNSS satellites. Here, i and j are arbitrary frequency points, which can be equal or unequal. Formula (1) represents the single-frequency carrier phase-smoothed pseudorange that can be smoothed using a carrier at any frequency.

[0045] In this embodiment, the ionospheric residual is subtracted using SBAS ionospheric delay information, which improves the pseudorange smoothing accuracy to a certain extent. As shown in formula (1), the coefficient (γ) of the ionospheric residual term is... i +γ j The smaller the value of γ, the smaller the impact of ionospheric residuals on pseudorange smoothing, and the higher the accuracy of pseudorange smoothing. Among these factors, the coefficient term (γ)... i +γ j ) in γ j This is related to the carrier frequency selected from the cycle-slip-free carriers. This embodiment smooths the pseudorange of all frequencies in a simple and practical way. As long as there is a continuous cycle-slip-free carrier at any frequency, pseudorange smoothing can continue without resetting the filter. This ensures that the pseudorange before and after the positioning frequency switching is smoothed, improving the smoothing accuracy. Furthermore, using an arbitrary single-frequency carrier to smooth the pseudorange of all frequencies reduces the large errors caused by positioning frequency switching.

[0046] In one exemplary instance, for the adaptive carrier phase smoothing pseudorange method applied to the case of dual-frequency carrier phase smoothing pseudorange, step 101 may include:

[0047] Substitute the two selected carrier frequencies into formula (2), and smooth the pseudorange of all frequencies in the current epoch one by one. In formula (2), k represents the current epoch, and (k-1) represents the previous epoch.

[0048]

[0049] In formula (2), Let i represent the smoothed pseudorange observations at epoch k and epoch (k-1) of frequency point i, respectively. This represents the raw pseudorange observation value at epoch k of frequency point i. γ represents the interepoch carrier increment at frequency point j. j γ n They represent These represent the differences between the carrier phase observations at frequencies j and n at epoch k and epoch k-1, respectively. In other words, in this embodiment, as long as there are consecutive cycle-slip-free carrier phase observations at any two frequencies, the ionospheric delay variation between epochs can be calculated. Thus, any two frequency carriers can be used to smooth the pseudorange at any frequency. Here, i is an arbitrary frequency, and formula (2) means that any two-frequency carriers, i.e., frequency j and frequency n, can be used to smooth the pseudorange at any frequency i using phase smoothing pseudorange.

[0050] In this embodiment, pseudorange at all frequencies is smoothed in a simple and practical way. As long as there are two consecutive carriers at any two frequencies without cycle slips, pseudorange smoothing can continue without resetting the filter. This ensures that the pseudorange before and after the positioning frequency switching is smoothed, improving the smoothing accuracy. Furthermore, using any single frequency carrier to smooth the pseudorange at all frequencies reduces the large errors caused by the positioning frequency switching.

[0051] In one exemplary instance, before counting the number of carrier frequency points that have not experienced cycle slips in the current epoch, the adaptive carrier phase smoothing pseudorange method provided in this application embodiment may further include: acquiring multi-frequency GNSS raw observation values.

[0052] In one embodiment, obtaining raw GNSS observations from multiple frequency points may include:

[0053] The original pseudorange and carrier phase observations of multi-frequency GNSS are obtained from the receiver. Taking three frequency points as an example, the original pseudorange observation equations for each frequency point i are shown in equation (3), and the original carrier phase observation equations are shown in equation (4). In this embodiment, i = 1, 2, and 3:

[0054]

[0055]

[0056]

[0057] In formulas (3) and (4), P i Φ i Let ρ and dT represent the equivalent distances of the original pseudorange observation and carrier phase observation at frequency i, respectively; ρ represents the satellite-to-ground distance, and dT represents the receiver clock bias. DCBiThe receiver hardware delay correction for frequency i is represented by dt, and the satellite clock bias is represented by T. GDi This indicates the satellite-side hardware delay correction for frequency point i, d iono Indicates ionospheric delay error correction, d trop Indicates tropospheric delay correction, N i λ represents the integer ambiguity of frequency point i. i f represents the signal wavelength at frequency i. i ε(P) represents the signal frequency at frequency point i. i ), ε(Φ i ) represent the pseudorange and carrier phase observation noise of frequency point i, respectively.

[0058] In one exemplary instance, when applying the adaptive carrier phase smoothing pseudorange method to the case of single-frequency carrier phase smoothing pseudorange, after acquiring the raw GNSS observations at multiple frequencies and before counting the number of carrier frequencies that have not experienced cycle slips in the current epoch, the method may further include:

[0059] First, maintain continuous observation of the GNSS satellite to obtain raw pseudorange and carrier phase observations at multiple epochs. Then, analyze the raw pseudorange and carrier phase observations at adjacent epochs t. k-1 t k By taking the difference between them, we can obtain the pseudorange increment and carrier increment between any frequency epoch, as shown in formulas (5) and (6), respectively:

[0060]

[0061]

[0062] In formulas (5) and (6), Let i represent the epoch-time pseudorange increment and the epoch-time carrier increment, respectively. This indicates the change in the distance between the Earth and the satellite over different epochs. This indicates the change in receiver clock bias between epochs. Indicates the changes in satellite clock bias between epochs. This indicates the delayed changes in the ionosphere between epochs. This indicates the tropospheric delay variation between epochs. These represent observation noise, respectively.

[0063] Then, the relationship between the pseudorange increment and the carrier increment at any frequency point is obtained by subtracting the pseudorange increment and the carrier increment at each frequency point.

[0064] Among them, by subtracting the epoch pseudorange increment and epoch carrier increment for each frequency point, taking the three frequency points as an example and ignoring the observation noise, we can obtain formulas (7) to (9):

[0065]

[0066]

[0067]

[0068] The relationship between pseudorange increment and carrier increment between any frequency epochs, obtained through summarization and induction, is shown in formula (10):

[0069]

[0070] In formula (10), i and j represent any two frequency points, γ i γ j They represent The epoch-time ionospheric delay change in the second term on the right side of the equation is a small value, but the effect of the residual in this term cannot be ignored when the ionosphere is active.

[0071] Next, SBAS improves the accuracy of the original GNSS positioning by broadcasting various correction information such as ephemeris error, satellite clock error, and ionospheric delay to users.

[0072] If the SBAS ionospheric grid can cover the satellite puncture point, then a more accurate amount of ionospheric delay change can be calculated using SBAS ionospheric delay information.

[0073] In one embodiment, the amount of ionospheric delay change is obtained. It can include:

[0074] By tracking SBAS satellite signals and acquiring SBAS ionospheric grid correction information, the puncture point positions of the satellite at epoch k and (k-1) are calculated. The vertical delay correction of the ionosphere at the puncture point is calculated by interpolation using the vertical delay correction information on the ionospheric grid points. Multiplying this by the tilt factor, the ionospheric delay corrections at epoch k and (k-1) are obtained. Subtracting these values ​​between epochs yields a relatively accurate inter-epoch ionospheric delay variation. Interepochal ionospheric delay change Substituting into formula (10), we get the following formula (11):

[0075]

[0076] In one embodiment, the ionospheric delay variation can also be calculated using an ionospheric error model based on GNSS satellite broadcasting.

[0077] Finally, based on formula (11), that is, based on the relationship between pseudorange increment and carrier increment between any frequency epochs, and the ionospheric delay change, the Hatch filtering formula is used to obtain the single-frequency carrier phase smooth pseudorange after deducting the ionospheric residual. The constructed single-frequency carrier smooth pseudorange equation is shown in formula (1).

[0078] In one exemplary instance, when applying the adaptive carrier phase smoothing pseudorange method to the case of dual-frequency carrier phase smoothing pseudorange, after obtaining the raw GNSS observations at multiple frequencies and before counting the number of carrier frequencies that have not experienced cycle slips in the current epoch, the method may further include:

[0079] First, the ionospheric residual is calculated using an arbitrary dual-frequency carrier wave.

[0080] Based on the original carrier phase observation equations for each frequency point shown in formula (4), first construct the carrier phase geometric-free combination (GF) observation equations for any two frequency points, and then transform them to make d iono With a coefficient of 1, ignoring observation noise, we can obtain formulas (12) to (14):

[0081]

[0082]

[0083]

[0084] When the carrier has no cycle slip, the right side of equations (12) to (14) divided by d iono All external values ​​are constant and do not change with time. Use ΔΦ mn C represents the difference between the carrier phase observations at frequencies m and n. mn To represent the constant value part, formulas (12) to (14) can be simplified to formulas (15) to (17) to obtain:

[0085]

[0086]

[0087]

[0088] Formulas (15) to (17) in adjacent epochs t k-1 t k By performing interepoch difference operations, we can obtain formulas (18) to (20):

[0089]

[0090]

[0091]

[0092] The equation for calculating the interepochal ionospheric delay change can be obtained by summarizing and generalizing, as shown in formula (21):

[0093]

[0094] In formula (21), γ m γ n They represent Let m and n represent the differences between the carrier phase observations at frequency points m and n in epoch k and (k-1) epochs, respectively. In other words, the ionospheric delay variation between epochs can be calculated as long as there are consecutive cycle-slip-free carrier phase observations at any two frequency points.

[0095] Then, substituting formula (21) into formula (10) yields formula (22):

[0096]

[0097] In formula (22), under the premise that m ≠ n, frequency points i, j, m, and n can be any frequency points, and they can be equal or unequal to each other. When assuming j = m or j = n, it means that a carrier with any frequency point is selected from the dual-frequency carriers used to calculate the ionospheric residual to construct the pseudorange smoothing equation, that is, pseudorange smoothing can be performed using only at least two cycle-slip-free carriers. Assuming j = m, formula (23) can be obtained from formula (22):

[0098]

[0099] Finally, based on formula (23), namely the relationship between pseudorange increment and carrier increment between arbitrary frequency epochs, the ionospheric delay change and Hatch filtering formula, the dual-frequency carrier phase smoothing pseudorange equation using arbitrary j and n dual-frequency carriers to smooth the pseudorange of arbitrary i frequency point is constructed as shown in formula (2).

[0100] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the adaptive carrier phase smoothing pseudorange method described in any of the preceding claims.

[0101] This application further provides an apparatus for implementing adaptive carrier phase smoothing pseudorange, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the adaptive carrier phase smoothing pseudorange method described in any of the preceding claims.

[0102] Figure 2This is a flowchart illustrating an embodiment of the adaptive single-frequency carrier phase smoothing pseudorange method in this application. This embodiment uses single-frequency carrier phase smoothing pseudorange as an example. Figure 2 As shown, it may include:

[0103] Step 200: Based on the multi-frequency raw pseudorange observations and carrier phase observations of epoch k and (k-1) epochs, obtain the relationship between pseudorange increment and carrier increment between any frequency epochs.

[0104] In one exemplary instance, step 200 may include:

[0105] Acquire raw GNSS observations from multiple frequency points;

[0106] Maintain continuous observation of GNSS satellites, acquire raw pseudorange and carrier phase observations at multiple epochs, and analyze the raw pseudorange and carrier phase observations at adjacent epochs t. k-1 t k By taking the difference between them, we can obtain the pseudorange increment and carrier increment between epochs at any frequency point;

[0107] The relationship between the pseudorange increment and carrier increment at any frequency point can be obtained by subtracting the pseudorange increment and carrier increment between epochs for each frequency point.

[0108] Step 201: Correct the ionospheric delay variation using SBAS ionospheric grid correction information or ionospheric error model parameters broadcast by satellite.

[0109] In one exemplary instance, step 201 may include:

[0110] By tracking SBAS satellite signals and obtaining SBAS ionospheric grid correction information, the puncture point positions of the satellite at epoch k and (k-1) are calculated respectively. The vertical delay correction of the ionosphere at the puncture point is calculated by interpolation using the vertical delay correction information on the ionospheric grid points. Multiplying this by the tilt factor, the ionospheric delay corrections of the satellite at epoch k and (k-1) are finally obtained. The difference between these epochs can be used to obtain a relatively accurate amount of ionospheric delay change between epochs. Alternatively, the amount of ionospheric delay change can be calculated using the ionospheric error model broadcast by GNSS satellites.

[0111] Step 202: Construct the smooth pseudorange equation for an arbitrary single-frequency carrier.

[0112] In one exemplary instance, a single-frequency carrier smoothing pseudorange equation is constructed using Hatch filtering, based on the relationship between pseudorange increments and carrier increments between arbitrary frequency epochs and the ionospheric delay variation.

[0113] Step 203: Determine whether there is a cycle slip for each frequency carrier and adaptively select a single-frequency carrier.

[0114] The implementation of this step can be found in steps 100 and 101, which describe the application of the adaptive carrier phase smoothing pseudorange method to single-frequency carrier phase smoothing pseudorange. It will not be repeated here.

[0115] Step 204: Smooth the pseudorange of all frequencies using the selected single-frequency carrier.

[0116] The implementation of this step can be found in step 102 regarding the application of the adaptive carrier phase smoothing pseudorange method to single-frequency carrier phase smoothing pseudorange, and will not be repeated here.

[0117] The adaptive single-frequency carrier phase smoothing pseudorange method provided in this application improves pseudorange smoothing accuracy by correcting ionospheric residuals using SBAS ionospheric grid correction information or ionospheric error model parameters broadcast by satellite during single-frequency carrier phase smoothing. When the selected frequency carrier experiences cycle slip, it adaptively selects a cycle-slip-free carrier to continue pseudorange smoothing, avoiding the problem of temporary pseudorange smoothing failure due to cycle slips of some frequency carriers, reducing the probability of filter reset. Furthermore, it uses the selected frequency carrier to smooth the pseudorange of all frequencies simultaneously, ensuring smoothing accuracy and effect. It is easy to implement and has practical application value.

[0118] The adaptive dual-frequency carrier phase smoothing pseudorange method provided in this application reduces the impact of ionospheric divergence error on single-frequency carrier phase smoothing pseudorange, overcomes the shortcomings of traditional carrier phase smoothing pseudorange technology which is limited to smoothing pseudorange at a certain frequency point only for a carrier at a certain frequency point, and the limitation that pseudorange smoothing will immediately fail temporarily once the selected carrier experiences a cycle slip.

[0119] Figure 3 This is a flowchart illustrating an embodiment of the adaptive dual-frequency carrier phase smoothing pseudorange method in this application. This embodiment uses dual-frequency carrier phase smoothing pseudorange as an example. Figure 3 As shown, it may include:

[0120] Step 300: Obtain the multi-frequency raw pseudorange observations and carrier phase observations for epochs k and (k-1). The implementation of this step is the same as described in step 200, and will not be repeated here.

[0121] Step 301: Construct the smooth pseudorange equation for an arbitrary dual-frequency carrier.

[0122] In one exemplary instance, this step may include:

[0123] Based on the original pseudorange and carrier phase observations of multi-frequency GNSS, construct a geometrically distance-free combined observation equation for the carrier phase of any two frequency points;

[0124] In adjacent epoch t k-1 t k The epoch-level ionospheric delay change is obtained by performing inter-epoch difference processing;

[0125] Based on the relationship between pseudorange increment and carrier increment between arbitrary frequency epochs, and the ionospheric delay variation, a single-frequency carrier smooth pseudorange equation is constructed using Hatch filtering.

[0126] Step 302: Determine whether there is cycle slip for each frequency carrier and adaptively select the dual-frequency carrier.

[0127] The implementation of this step can be found in steps 100 and 101, which describe the application of the adaptive carrier phase smoothing pseudorange method to dual-frequency carrier phase smoothing pseudorange. It will not be repeated here.

[0128] Step 303: Smooth the pseudorange of all frequencies using the selected dual-frequency carrier.

[0129] The implementation of this step can be found in step 102, which describes the application of the adaptive carrier phase smoothing pseudorange method to dual-frequency carrier phase smoothing pseudorange. It will not be repeated here.

[0130] The adaptive dual-frequency carrier phase smoothing pseudorange method provided in this application realizes the adaptive selection of a carrier without cycle slip when the selected frequency carrier cycle slips, thus avoiding the problem of temporary failure of pseudorange smoothing due to cycle slip of some frequency carriers, reducing the probability of filter reset. Furthermore, by using the selected frequency carrier to smooth the pseudorange of all frequencies at the same time, the smoothing accuracy and effect are guaranteed. It is easy to implement and has practical application value.

[0131] Figure 4 This is a schematic diagram of the composition structure of the adaptive carrier phase smoothing pseudorange device in the embodiments of this application, as shown below. Figure 4 As shown, it includes: a judgment module and a smoothing module, wherein,

[0132] The judgment module is used to select one or more frequency carriers corresponding to the pseudorange smoothing condition from the carriers without cycle slips if the number of frequency points that have not experienced cycle slips in the current epoch meets the pseudorange smoothing condition.

[0133] The smoothing module is used to smooth the pseudorange of the current epoch frequency point based on the smoothed pseudorange observation value of the previous epoch and the inter-epoch carrier increment of one or more selected frequency points.

[0134] In one exemplary instance, it may further include: a detection module, used to perform cycle slip detection on the carrier phase of all frequency points, determine whether a cycle slip has occurred on each frequency point carrier, and count the number of carrier frequency points that have not experienced a cycle slip in the current epoch.

[0135] In one exemplary instance, it also includes: an acquisition module for acquiring raw pseudorange and carrier phase observations of multi-frequency GNSS.

[0136] In one exemplary instance, the system further includes a construction module for constructing a carrier smoothing pseudorange equation for smoothing pseudorange at all frequencies, based on the relationship between pseudorange increments and carrier increments between any frequency epochs, the ionospheric delay variation, and the Hatch filtering formula.

[0137] In one exemplary instance, for the adaptive carrier phase smoothing pseudorange method applied to the case of single-frequency carrier phase smoothing pseudorange, the construction module is used to:

[0138] Obtain raw pseudorange and carrier phase observations from multiple epochs, and then analyze the raw pseudorange and carrier phase observations at adjacent epochs t. k-1 t k The difference between them is calculated; the relationship between the pseudorange increment and carrier increment at any frequency point is obtained by subtracting the pseudorange increment and carrier increment at each frequency point respectively; the ionospheric delay variation is obtained. Based on the relationship between pseudorange increment and carrier increment between arbitrary frequency epochs, and the ionospheric delay variation, the single-frequency carrier phase smooth pseudorange after deducting the ionospheric residual is obtained using the Hatch filtering formula, and the single-frequency carrier smooth pseudorange equation is constructed.

[0139] In one exemplary instance, for the adaptive carrier phase smoothing pseudorange method applied to the case of dual-frequency carrier phase smoothing pseudorange, the construction module is used to:

[0140] Based on the original carrier phase observation equations for each frequency point shown in formula (4), that is, based on the original pseudorange and carrier phase observation values ​​of the multi-frequency GNSS, first construct the GF observation equations for any two frequency points, and then in adjacent epochs t k-1 t k After performing inter-epoch differential processing, the inter-epoch ionospheric delay variation is obtained; based on the relationship between the inter-epoch pseudorange increment and carrier increment at any frequency point, the ionospheric delay variation, and the Hatch filtering formula, a dual-frequency carrier phase smoothing pseudorange equation is constructed.

[0141] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A method for adaptive carrier phase smoothing pseudorange, characterized in that, include: If the number of frequency points that have not experienced cycle slips in the current epoch satisfies the pseudorange smoothing condition, select one or more frequency point carriers corresponding to the pseudorange smoothing condition from the cycle-slip-free carriers, including: When the method is applied to the case of pseudorange phase smoothing of a single-frequency carrier, one frequency carrier is randomly selected from the number of frequency points without cycle slips in the current epoch as the frequency carrier for pseudorange smoothing; or, the frequency point with the smallest ionospheric mapping factor is selected from the number of frequency points without cycle slips in the current epoch as the frequency carrier for pseudorange smoothing. When the method is applied to the case of pseudorange phase smoothing of dual-frequency carriers, if the number of frequency points without cycle slips in the current epoch is 2, then the number of frequency points without cycle slips and the number of carriers without cycle slips are selected as the two frequency point carriers for pseudorange smoothing; if the number of frequency points without cycle slips in the current epoch is greater than 2, then any two frequency point carriers are selected from the number of frequency points without cycle slips and the number of carriers without cycle slips as the frequency point carriers for pseudorange smoothing. Based on the smoothed pseudorange observations from the previous epoch and the inter-epoch carrier increments of one or more selected frequency points, smooth the pseudorange of each frequency point in the current epoch.

2. The method according to claim 1, wherein, When the method is applied to the case of single-frequency carrier phase smoothing pseudorange, the pseudorange smoothing condition includes: the number of frequency points that do not experience cycle slips is greater than or equal to 1. Among them, ionospheric mapping factor ,in, This indicates the signal frequency at frequency point 1. This indicates the signal frequency at the currently selected frequency point j.

3. The method according to claim 1, wherein, When the method is applied to the case of dual-frequency carrier phase smoothing pseudorange, the pseudorange smoothing condition includes: the number of frequency points that do not experience cycle slips is greater than or equal to 2.

4. The method according to claim 2, wherein, The smoothing of pseudoranges at each frequency point in the current epoch includes: Substitute the selected carrier frequency point into the formula for single-frequency carrier phase smoothing pseudorange using arbitrary frequency carrier smoothing, and smooth the pseudorange of all frequencies in the current epoch one by one: ， in, , Let i represent the smoothed pseudorange observations at epoch k and epoch (k-1) of frequency point i, respectively. This represents the raw pseudorange observation value at epoch k of frequency point i. This represents the interepoch carrier increment at frequency point j. This represents the change in ionospheric delay between epochs; where i and j are arbitrary frequency points.

5. The method according to claim 3, wherein, The smoothing of pseudoranges at each frequency point in the current epoch includes: Substitute the two selected carrier frequencies into the following formula for smoothing pseudorange of arbitrary frequency i using any dual-frequency carrier (i.e., frequency j and frequency n), and smooth the pseudorange of all frequencies one by one: ， in, , Let i represent the smoothed pseudorange observations at epoch k and epoch (k-1) of frequency point i, respectively. This represents the raw pseudorange observation value at epoch k of frequency point i. This represents the interepoch carrier increment at frequency point j. , They represent , , , Let i and n represent the differences in carrier phase observations between frequency points j and n at epoch k and epoch k-1, respectively; where i is an arbitrary frequency point.

6. The method according to claim 4 or 5, wherein the method is applied to single-frequency carrier phase smoothing pseudorange, and further constructs a single-carrier smoothing pseudorange equation, comprising: Determine the pseudorange increment and carrier increment between epochs at any frequency point; The relationship between the pseudorange increment and the carrier increment at any frequency point can be obtained by subtracting the pseudorange increment and the carrier increment at each frequency point. The ionospheric delay variation can be corrected using SBAS ionospheric grid correction information or ionospheric error model parameters broadcast by satellite. Based on the relationship between pseudorange increment and carrier increment between arbitrary frequency epochs, and the ionospheric delay variation, the single-frequency carrier smooth pseudorange equation is constructed.

7. The method according to claim 4 or 5, wherein the method is applied to dual-frequency carrier phase smoothing pseudorange, and a dual-carrier smoothing pseudorange equation is further constructed, comprising: Based on the original pseudorange and carrier phase observations of multi-frequency GNSS, construct a geometrically distance-free combined observation equation for the carrier phase of any two frequency points; The epoch-level ionospheric delay change is obtained by performing inter-epoch difference processing between adjacent epochs. Based on the relationship between pseudorange increment and carrier increment between arbitrary frequency epochs, the ionospheric delay variation, and the Hatch filtering formula, the dual-frequency carrier phase smoothing pseudorange equation is constructed.

8. A computer-readable storage medium storing computer-executable instructions for performing the adaptive carrier phase smoothing pseudorange method according to any one of claims 1 to 7.

9. An adaptive carrier phase smoothing pseudorange device, comprising a memory and a processor, wherein, The memory stores the following instructions executable by a processor: steps for performing the adaptive carrier phase smoothing pseudorange method according to any one of claims 1 to 7.

10. An apparatus for adaptive carrier phase smoothing pseudorange, characterized in that, include: The judgment module and the smoothing module, among which, The judgment module is used to select one or more frequency carriers corresponding to the pseudorange smoothing condition from the number of frequency points without cycle slips in the current epoch, provided that the number of frequency points without cycle slips in the current epoch meets the pseudorange smoothing condition. This includes: for cases where the device is applied to single-frequency carrier phase smoothing pseudorange, arbitrarily selecting one frequency carrier from the number of frequency points without cycle slips in the current epoch and the number of cycle slip-free carriers as the frequency carrier for pseudorange smoothing; or, selecting an ionospheric mapping factor from the number of frequency points without cycle slips in the current epoch and the number of cycle slip-free carriers. The smallest frequency point is used as the frequency carrier for pseudorange smoothing; for the case where the device is applied to dual-frequency carrier phase smoothing pseudorange, when the number of frequency points without cycle slips in the current epoch is 2, the number of cycle-slip-free carriers of the number of frequency points without cycle slips is selected as the two frequency carriers for pseudorange smoothing; when the number of frequency points without cycle slips in the current epoch is greater than 2, two frequency carriers are arbitrarily selected from the number of cycle-slip-free carriers of the number of frequency points without cycle slips as the frequency carriers for pseudorange smoothing. The smoothing module is used to smooth the pseudorange of each frequency point in the current epoch based on the smoothed pseudorange observation value of the previous epoch and the inter-epoch carrier increment of one or more selected frequency points.

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