GNSS positioning method, device, GNSS receiver and storage medium

Abstract

The embodiment of the present invention proposes a GNSS positioning method, device, GNSS receiver and storage medium, which relate to the field of satellite navigation. The method uses the original observation quantity and ephemeris between epochs to perform differential navigation positioning. First, the carrier phase epoch differential equation is constructed, and positioning is performed according to the first solution result obtained by solving the carrier phase epoch differential equation. If the positioning fails, the Doppler observation equation is continued to be constructed, and positioning is performed according to the second solution result obtained by simultaneously solving the carrier phase epoch differential equation and the Doppler observation equation. If the positioning fails, the pseudo-range epoch differential equation is continued to be constructed, and positioning is performed according to the third solution result obtained by simultaneously solving the carrier phase epoch differential equation, the Doppler observation equation and the pseudo-range epoch differential equation. The present invention realizes the inter-epoch differential positioning of adaptive fusion of carrier phase, Doppler and pseudorange, so it can effectively improve the efficiency, accuracy and robustness of GNSS positioning.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation technology, and in particular to a GNSS positioning method, device, GNSS receiver and storage medium. Background Art

[0002] With the continuous advancement of technology, applications such as autonomous driving and artificial intelligence are placing increasing demands on the real-time performance, positioning accuracy, and robustness of the Global Navigation Satellite System (GNSS). In complex scenarios like elevated roads, tree-lined roads, and urban canyons, where GNSS observations are scarce and gross errors are frequent, improving GNSS positioning and navigation accuracy has become a pressing issue. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a GNSS positioning method, apparatus, GNSS receiver and storage medium, which can effectively improve the efficiency, accuracy and robustness of GNSS positioning.

[0004] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0005] In a first aspect, the present invention provides a GNSS positioning method, applied to a GNSS receiver, the method comprising:

[0006] Determine the target carrier phase, target Doppler, and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch;

[0007] Obtaining a carrier phase inter-epoch differential equation based on the target carrier phase, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch;

[0008] Solving the carrier phase inter-epoch differential equation to obtain a first solution result; if the first solution result indicates successful positioning, obtaining the absolute position of the current epoch based on the first solution result; if the first solution result indicates a positioning failure, obtaining a Doppler observation equation based on the target Doppler, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch;

[0009] Solving the carrier phase epoch-to-epoch differential equation and the Doppler observation equation to obtain a second solution result; if the second solution result indicates successful positioning, obtaining the absolute position of the current epoch according to the second solution result; if the second solution result indicates a positioning failure, obtaining the pseudorange-to-epoch differential equation according to the target pseudorange, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch;

[0010] Solving the carrier phase epoch differential equation, the Doppler observation equation, and the pseudorange epoch differential equation to obtain a third solution result; if the third solution result indicates successful positioning, obtaining the absolute position of the current epoch according to the third solution result.

[0011] In an optional embodiment, determining the target carrier phase, target Doppler, and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch includes:

[0012] Determine the satellite elevation angles of all satellites based on the GNSS raw observations of the current epoch;

[0013] Determine the satellite whose elevation angle exceeds the preset elevation angle as a candidate satellite;

[0014] Determine the GNSS raw observations of the current epoch in which the candidate satellite does not have a cycle slip as the primary observations;

[0015] Determine the GNSS original observation of the previous epoch and the same observation in the preliminary selected observation as the candidate observation;

[0016] Abnormal observation quantities are eliminated from the candidate observation quantities according to the estimated value of the GNSS receiver clock error variation to obtain the target carrier phase, the target Doppler, and the target pseudorange.

[0017] In an optional embodiment, the GNSS raw observations include carrier phase and carrier phase noise; and the step of obtaining the carrier phase inter-epoch difference equation based on the target carrier phase, the GNSS raw observations of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch comprises:

[0018] Determine the satellite position change between epochs and the satellite clock error change between epochs based on the ephemeris of the current epoch and the ephemeris of the previous epoch;

[0019] Determining an inter-epoch carrier phase variation based on the target carrier phase and the corresponding carrier phase of the previous epoch;

[0020] Determine the carrier phase noise variation between epochs based on the carrier phase noise of the current epoch and the carrier phase noise of the previous epoch;

[0021] A carrier phase inter-epoch differential equation is constructed based on the carrier phase wavelength, the carrier phase change between epochs, the satellite clock error change between epochs, the carrier phase noise change between epochs, the GNSS receiver clock error change between epochs, the satellite position change between epochs, and the position change of the current epoch.

[0022] In an optional embodiment, the GNSS raw observations further include Doppler and Doppler noise; the first solution result includes the position change of the current epoch, the GNSS receiver clock error change between the epochs, and the target carrier phase quantity; if the first solution result indicates positioning failure, the step of obtaining a Doppler observation equation based on the target Doppler, the GNSS raw observations of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch comprises:

[0023] Determining a carrier phase posterior-validation residual corresponding to the target carrier phase based on the inter-epoch carrier phase change, the inter-epoch satellite position change, the position change of the current epoch, and the inter-epoch GNSS receiver clock error change;

[0024] When the carrier phase post-verification residual satisfies the chi-square test, it is determined whether the target carrier phase quantity exceeds a preset carrier phase quantity threshold, and if so, the positioning is successful;

[0025] If not exceeded, a Doppler observation is determined according to the target Doppler and the Doppler of the corresponding previous epoch, and an inter-epoch Doppler noise variation is determined according to the Doppler noise of the current epoch and the Doppler noise of the previous epoch. A Doppler observation equation is constructed according to the Doppler observation, the inter-epoch time interval, the carrier phase wavelength, the inter-epoch satellite clock difference variation, the inter-epoch Doppler noise variation, the inter-epoch GNSS receiver clock difference variation, the inter-epoch satellite position variation, and the position change of the current epoch.

[0026] In an optional embodiment, the method further comprises:

[0027] When the carrier phase post-test residual does not satisfy the chi-square test, obtaining a corresponding normalized carrier phase residual according to the carrier phase post-test residual;

[0028] Updating the weight of the target carrier phase according to the value range of each of the standardized carrier phase residuals;

[0029] The carrier phases with a weight of 0 of the target carrier phase are eliminated to obtain an updated target carrier phase, so that the carrier phase inter-epoch difference equation is re-solved according to the updated target carrier phase.

[0030] In an optional embodiment, the GNSS raw observations further include pseudoranges and pseudorange noise; the second solution result includes a position change of the current epoch, a GNSS receiver clock error change between epochs, a target carrier phase quantity, and a target Doppler quantity; and if the second solution result indicates positioning failure, the step of obtaining a pseudorange-epoch difference equation based on the target pseudorange, the GNSS raw observations of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch comprises:

[0031] Determining a Doppler posterior residual corresponding to the target Doppler based on the Doppler observation, the satellite position change between epochs, the position change of the current epoch, and the GNSS receiver clock difference change between epochs;

[0032] When both the carrier phase post-test residual and the Doppler post-test residual satisfy the chi-square test, it is determined whether the target carrier phase number exceeds a preset carrier phase number threshold and whether the target Doppler number exceeds a preset Doppler number threshold, and if so, the positioning is successful;

[0033] If it does not exceed, the inter-epoch pseudorange change is determined according to the target pseudorange and the corresponding pseudorange of the previous epoch, the inter-epoch pseudorange noise change is determined according to the pseudorange noise of the current epoch and the pseudorange noise of the previous epoch, and the inter-epoch pseudorange change, the inter-epoch satellite clock difference change, the inter-epoch pseudorange noise change, the inter-epoch GNSS receiver clock difference change, the inter-epoch satellite position change and the position change of the current epoch are used to construct a pseudorange inter-epoch differential equation.

[0034] In an optional embodiment, after determining the target carrier phase, target Doppler, and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch, the method further includes:

[0035] According to the number of target carrier phases, target Dopplers and target pseudoranges in each signal frequency, the corresponding frequency weight is obtained;

[0036] Each time, a corresponding target signal frequency is determined in descending order of frequency weights, so as to perform GNSS positioning according to the target carrier phase, target Doppler and target pseudorange corresponding to the target signal frequency.

[0037] In a second aspect, the present invention provides a GNSS positioning device, applied to a GNSS receiver, the device comprising:

[0038] A preprocessing module is used to determine the target carrier phase, target Doppler and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch;

[0039] A positioning module is configured to obtain a carrier phase inter-epoch differential equation based on the target carrier phase, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; solve the carrier phase inter-epoch differential equation to obtain a first solution result; if the first solution result indicates a successful positioning, obtain the absolute position of the current epoch based on the first solution result; if the first solution result indicates a failed positioning, obtain a Doppler observation equation based on the target Doppler, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; solve the carrier phase inter-epoch differential equation and the Doppler observation equation to obtain a second solution result; if the second solution result indicates that positioning is successful, the absolute position of the current epoch is obtained according to the second solution result; if the second solution result indicates that positioning fails, the pseudorange epoch difference equation is obtained according to the target pseudorange, the GNSS original observation of the previous epoch, the ephemeris of the current epoch and the ephemeris of the previous epoch; the carrier phase epoch difference equation, the Doppler observation equation and the pseudorange epoch difference equation are solved to obtain a third solution result; if the third solution result indicates that positioning is successful, the absolute position of the current epoch is obtained according to the third solution result.

[0040] In a third aspect, the present invention provides a GNSS receiver, comprising a processor and a memory, wherein the memory stores machine-executable instructions that can be executed by the processor, and the processor can execute the machine-executable instructions to implement the GNSS positioning method described in any of the aforementioned embodiments.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the GNSS positioning method as described in any one of the aforementioned embodiments.

[0042] Compared with the existing technology, the GNSS positioning method, device, GNSS receiver and storage medium provided by the embodiments of the present invention use the GNSS original observations and ephemeris between adjacent epochs for differential navigation positioning. First, a carrier phase differential equation between epochs is constructed, and the success of the positioning is determined based on the first solution result obtained by solving the carrier phase differential equation between epochs. If the positioning is successful, the absolute position of the GNSS receiver in the current epoch is directly determined based on the first solution result.

[0043] If positioning fails, continue to construct the Doppler observation equation, and simultaneously solve the carrier phase epoch differential equation and the Doppler observation equation to obtain a second solution result, and judge whether the positioning is successful based on the second solution result. If positioning is successful, directly determine the absolute position of the current epoch of the GNSS receiver based on the second solution result; if positioning fails, continue to construct the pseudorange epoch differential equation, and simultaneously solve the carrier phase epoch differential equation, the Doppler observation equation and the pseudorange epoch differential equation to obtain a third solution result, and perform GNSS positioning based on the third solution result.

[0044] The present invention realizes inter-epoch differential positioning by adaptively fusing carrier phase, Doppler and pseudorange, thereby effectively improving the efficiency, accuracy and robustness of GNSS positioning, while also improving the success rate of constructing the carrier phase inter-epoch differential equation, the Doppler observation equation and the pseudorange inter-epoch differential equation.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 A schematic diagram of a scenario provided by an embodiment of the present invention is shown.

[0048] Figure 2 A schematic diagram of a flow chart of a GNSS positioning method provided by an embodiment of the present invention is shown.

[0049] Figure 3 A block diagram of a GNSS positioning device provided by an embodiment of the present invention is shown.

[0050] Figure 4 A block diagram of a GNSS receiver provided by an embodiment of the present invention is shown.

[0051] Icon: 100 - GNSS receiver; 200 - satellite; 110 - memory; 120 - processor; 130 - communication module; 300 - GNSS positioning device; 301 - pre-processing module; 302 - positioning module. DETAILED DESCRIPTION

[0052] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0054] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0055] GNSS is an all-weather, global, high-precision radio navigation technology that can obtain absolute position coordinates at any time and any location. It can be applied to surveying, mapping, autonomous driving, and other fields. With the development of the autonomous driving industry, higher demands are being placed on the real-time performance, positioning accuracy, continuity, and reliability of GNSS positioning.

[0056] The inventors discovered that Time-Differenced Carrier Phase (TDCP) and Time-Differenced Pseudorange (TDPR) are inter-epoch differential navigation and positioning methods that differentiate the carrier phase and pseudorange between adjacent epochs. Combined with Doppler velocity measurement, these three methods can be applied to velocity and position estimation and can also be used to integrate sensors to improve positioning accuracy. This is crucial for autonomous driving systems, which require accurate position data for path planning and real-time decision-making.

[0057] However, the inter-epoch differential navigation method in the existing technology has relatively strict requirements on the actual application scenarios, and the GNSS receiver needs to use measurement equipment, which is usually expensive to purchase. This will make low-cost GNSS receivers unusable in complex roadside scenarios. At the same time, in complex scenarios such as elevated roads, tree-lined roads, and urban canyons, the existing inter-epoch differential method will obtain the wrong absolute position of the current epoch of the GNSS receiver due to the small number of observations and frequent gross errors, or even fail to obtain the absolute position of the current epoch of the GNSS receiver.

[0058] Based on this, the GNSS positioning method and device provided by the embodiments of the present invention use the GNSS original observations and ephemeris between adjacent epochs for differential positioning. First, a carrier phase differential equation between epochs is constructed, and the success of the positioning is determined based on the first solution result obtained by solving the carrier phase differential equation between epochs. If the positioning is successful, the absolute position of the GNSS receiver in the current epoch is directly determined based on the first solution result.

[0059] If positioning fails, continue to construct the Doppler observation equation, and simultaneously solve the carrier phase epoch differential equation and the Doppler observation equation to obtain a second solution result, and judge whether the positioning is successful based on the second solution result. If positioning is successful, directly determine the absolute position of the current epoch of the GNSS receiver based on the second solution result; if positioning fails, continue to construct the pseudorange epoch differential equation, and simultaneously solve the carrier phase epoch differential equation, the Doppler observation equation and the pseudorange epoch differential equation to obtain a third solution result, and perform GNSS positioning based on the third solution result.

[0060] The present invention realizes inter-epoch differential positioning by adaptively fusing carrier phase, Doppler and pseudorange, thereby effectively improving the efficiency, accuracy and robustness of GNSS positioning, while also improving the success rate of constructing the carrier phase inter-epoch differential equation, the Doppler observation equation and the pseudorange inter-epoch differential equation.

[0061] Please refer to Figure 1 , Figure 1 A schematic diagram of a scenario provided by an embodiment of the present invention is shown. Figure 1 In the embodiment, GNSS receiver 100 is in communication with N satellites 200. GNSS receiver 100 is configured to record raw GNSS observations for each epoch and to receive ephemeris for each epoch transmitted by N satellites 200. GNSS receiver 100 executes steps S10 to S90 and corresponding sub-steps in the following embodiments to achieve the corresponding technical effects.

[0062] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0063] Please refer to Figure 2 , Figure 2 A flow chart of a GNSS positioning method provided by an embodiment of the present invention is shown. The method can be applied to the above-mentioned GNSS receiver 100, and the method includes the following steps:

[0064] Step S10: determining a target carrier phase, a target Doppler, and a target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch.

[0065] Step S20 , obtaining a carrier phase inter-epoch differential equation based on the target carrier phase, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch.

[0066] Step S30: Solve the carrier phase inter-epoch difference equation to obtain a first solution result.

[0067] In an embodiment of the present invention, the target carrier phase, target Doppler, and target pseudorange are selected based on the raw GNSS observations between adjacent epochs. First, a carrier phase inter-epoch difference equation is constructed based on the target carrier phase, and the carrier phase inter-epoch difference equation is solved to obtain a first solution result.

[0068] Step S40: If the first solution result indicates successful positioning, the absolute position of the current epoch is obtained according to the first solution result.

[0069] Step S50: If the first solution result indicates positioning failure, a Doppler observation equation is obtained based on the target Doppler, the GNSS raw observation value of the previous epoch, the ephemeris of the current epoch and the ephemeris of the previous epoch.

[0070] Step S60: Solve the carrier phase inter-epoch difference equation and the Doppler observation equation to obtain a second solution result.

[0071] In this embodiment of the present invention, if the first solution indicates successful positioning, the absolute position of the GNSS receiver at the current epoch is directly obtained based on the first solution, and the positioning process is terminated. If positioning fails, a Doppler observation equation is constructed based on the target Doppler, and the carrier phase inter-epoch difference equation and the Doppler observation equation are solved simultaneously to obtain a second solution.

[0072] Step S70: If the second solution result indicates successful positioning, the absolute position of the current epoch is obtained according to the second solution result.

[0073] Step S80: If the second solution result indicates positioning failure, a pseudorange-epoch difference equation is obtained based on the target pseudorange, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch.

[0074] Step S90, solving the carrier phase epoch difference equation, the Doppler observation equation and the pseudorange epoch difference equation to obtain a third solution result; if the third solution result indicates successful positioning, the absolute position of the current epoch is obtained according to the third solution result.

[0075] In this embodiment of the present invention, if the second solution obtained by simultaneously solving the carrier phase epoch difference equation and the Doppler observation equation indicates successful positioning, the positioning process is terminated and the absolute position of the GNSS receiver at the current epoch is obtained based on the second solution. If positioning fails, the pseudorange epoch difference equation is constructed based on the target pseudorange, and the carrier phase epoch difference equation, the Doppler observation equation, and the pseudorange epoch difference equation are simultaneously solved to obtain a third solution, and positioning is then performed based on the third solution.

[0076] In summary, the GNSS positioning method provided in the embodiment of the present invention uses the GNSS original observations and ephemeris between adjacent epochs for differential navigation positioning. First, a carrier phase differential equation between epochs is constructed, and the success of the positioning is determined based on the first solution result obtained by solving the carrier phase differential equation between epochs. If the positioning is successful, the absolute position of the GNSS receiver in the current epoch is directly determined based on the first solution result.

[0077] If positioning fails, continue to construct the Doppler observation equation, and simultaneously solve the carrier phase epoch differential equation and the Doppler observation equation to obtain a second solution result, and judge whether the positioning is successful based on the second solution result. If positioning is successful, directly determine the absolute position of the current epoch of the GNSS receiver based on the second solution result; if positioning fails, continue to construct the pseudorange epoch differential equation, and simultaneously solve the carrier phase epoch differential equation, the Doppler observation equation and the pseudorange epoch differential equation to obtain a third solution result, and perform GNSS positioning based on the third solution result.

[0078] The present invention realizes inter-epoch differential positioning by adaptively fusing carrier phase, Doppler and pseudorange, thereby effectively improving the efficiency, accuracy and robustness of GNSS positioning, while also improving the success rate of constructing the carrier phase inter-epoch differential equation, the Doppler observation equation and the pseudorange inter-epoch differential equation.

[0079] In addition, since the GNSS positioning method provided by the embodiment of the present invention can effectively improve the efficiency and accuracy of GNSS positioning, it effectively reduces the precision requirements of the GNSS receiver. The GNSS positioning method provided by the embodiment of the present invention can be implemented using a low-cost GNSS receiver in a complex environment, which can effectively reduce the cost of GNSS positioning, thereby improving the practicality of low-cost GNSS receivers in application scenarios such as autonomous driving, agricultural machinery autonomous driving, and artificial intelligence.

[0080] Optionally, in practical applications, screening candidate satellites that meet the conditions can effectively improve the influence of factors such as multipath effects. At the same time, by detecting cycle slips and eliminating outliers, the target carrier phase, target Doppler and target pseudorange used for GNSS positioning can be determined, thereby effectively improving the GNSS positioning accuracy.

[0081] Figure 2 The sub-steps of step S10 may include:

[0082] The satellite elevation angles of all satellites are determined based on the GNSS raw observations of the current epoch, and satellites whose satellite elevation angles exceed the preset elevation angles are determined as candidate satellites; the GNSS raw observations of the current epoch in which the candidate satellites do not experience cycle slips are determined as preliminary observations, and the same observations in the GNSS raw observations of the previous epoch and the preliminary observations are determined as candidate observations; abnormal observations are eliminated from the candidate observations based on the estimated value of the GNSS receiver clock error change to obtain the target carrier phase, target Doppler and target pseudorange.

[0083] In this embodiment of the present invention, a preset elevation angle is obtained, satellites are screened based on the preset elevation angle, and satellites with elevation angles exceeding the preset elevation angle are identified as candidate satellites. For example, assuming the preset elevation angle is 10 degrees, satellites with elevation angles greater than 10 degrees are screened as candidate satellites. In practice, the preset elevation angle can be adjusted based on the quality of the raw GNSS observations used.

[0084] After obtaining the candidate satellites, the geometry-free (GF) method or the Doppler and carrier consistency method is used to perform cycle slip detection on the GNSS raw observations of the current epoch of the candidate satellites, and the GNSS raw observations of the current epoch without cycle slips are used as the initial observations.

[0085] In order to achieve inter-epoch differential navigation, it is necessary to ensure that the candidate satellite has observations in both the current epoch and the previous epoch. That is to say, when the same observation as the initial observation can be found in the GNSS raw observations of the previous epoch, the corresponding initial observation is determined as the candidate observation.

[0086] In an embodiment of the present invention, it is assumed that the position of the GNSS receiver in the current epoch has not changed, the inter-epoch satellite position change and the inter-epoch satellite clock difference change are determined based on the ephemeris of the current epoch and the ephemeris of the previous epoch, the Doppler observation is determined based on the candidate observation and the original observation of the previous epoch, and the GNSS receiver clock difference change estimate is determined based on the Doppler observation, the inter-epoch satellite position change, and the inter-epoch satellite clock difference change.

[0087] The outliers in the GNSS receiver clock error change estimate are eliminated by using the absolute median difference algorithm, standard deviation algorithm and other outlier removal methods, and the target carrier phase, target Doppler and target pseudorange are determined based on the candidate observations corresponding to the screened GNSS receiver clock error change estimate.

[0088] It should be noted that the embodiment of the present invention does not limit the execution order of the three operations of detecting cycle slips, screening the observations that are the same as the current epoch and the previous epoch, and eliminating abnormal observations, and can be processed according to actual applications.

[0089] GNSS raw observations are the raw data recorded by GNSS receivers, including information such as carrier phase, Doppler, and pseudorange. Pseudorange measurements use ranging codes as the measurement signal. Using code correlation, the measurement accuracy is generally around 1% of the code element width. Due to the large code element width of ranging codes, measurement accuracy is generally low. For example, C / A code pseudorange has a measurement accuracy of approximately ±3 meters, which meets the requirements of satellite navigation and low-precision positioning.

[0090] The wavelength of the carrier wave is much shorter, only 19 to 25 centimeters, so if the carrier wave phase is measured, a higher degree of accuracy can be achieved. Satellite Doppler measurement involves measuring the Doppler frequency shift or Doppler count of the radio signal broadcast by the satellite using a satellite signal receiver.

[0091] The epoch-to-epoch difference is performed on the original GNSS observations to obtain the inter-epoch differential observation value. The expression of the inter-epoch differential observation value can be:

[0092]

[0093] Where i is the signal frequency number, which is used to distinguish different signal frequencies; c is the speed of light, in meters; λ i is the carrier phase wavelength in meters; s is the satellite number, ranging from 1 to N; Δ is the inter-epoch differential operator, ΔR can be determined based on the carrier phase, pseudorange or Doppler, and is expressed as or

[0094] is the carrier phase variation between epochs, is the carrier phase of the signal frequency i from the GNSS receiver r to the satellite s, in cycles; is the pseudorange variation between epochs, is the pseudorange from GNSS receiver r to satellite s signal frequency i, in meters; is the Doppler observation quantity, is the Doppler of the signal frequency i from the GNSS receiver r to the satellite s in Hertz, and t is the time in seconds.

[0095] is the change in the geometric distance between the GNSS receiver r and the satellite s between epochs, in meters; Δδdt r is the change in GNSS receiver clock error between epochs, in seconds; ΔδT s is the change in satellite clock error between epochs, in seconds; is the ionospheric delay variation between epochs of the GNSS receiver r and the satellite s signal frequency i, in meters; is the inter-epoch tropospheric delay variation from GNSS receiver r to satellite s, in meters; Δbias i,r Δbias is the change in GNSS receiver hardware delay between epochs; i,s is the change in satellite s hardware delay between epochs; is the change in the ambiguity over the entire cycle between epochs; is the noise variation of satellite s signal frequency between epochs i.

[0096] In general, the resolution frequency of GNSS receivers is 10 Hz to 1 Hz, and the time interval between adjacent epochs is relatively short. Due to the high temporal correlation of some errors, the ionospheric delay variation between epochs is Change in tropospheric delay between epochs GNSS receiver hardware delay variation Δbias between epochs i,r and the satellite hardware delay variation Δbias between epochs i,s , the changes of the above parameters between epochs are extremely small and can be ignored. Moreover, when the carrier phase does not cycle slip, the whole cycle ambiguity will not change, that is, is 0.

[0097] Therefore, the expression of the difference observation value between epochs can be transformed into:

[0098]

[0099] In the above formula The calculation formula is:

[0100]

[0101] Where k represents the kth epoch, and k-1 represents the k-1th epoch; and They are the k-epoch satellite position and the GNSS receiver position respectively. The satellite position can be calculated using the ephemeris broadcast by the satellite, which will not be elaborated in the present invention. is the unit vector between the satellite and the GNSS receiver, which can be expressed as Since the satellite travels about 3 kilometers per second, which is very small compared to the 20,000 kilometers distance between the GNSS receiver and the satellite, and The difference can be ignored.

[0102] The calculation formula can be simplified as:

[0103]

[0104] in, is the satellite position change between epochs k-1 and k; is the GNSS receiver position change between epochs k-1 and k, that is, the position change of the current epoch (ΔX, ΔY, ΔZ).

[0105] Alternatively, in practical applications, in order to improve the real-time performance and accuracy of GNSS positioning, the carrier phase epoch difference equation is first constructed and solved separately for GNSS positioning. The original GNSS observations include carrier phase and carrier phase noise. Figure 2 The sub-steps of step S20 may include:

[0106] Based on the ephemeris of the current epoch and the ephemeris of the previous epoch, the satellite position change between epochs and the satellite clock error change between epochs are determined; based on the target carrier phase and the corresponding carrier phase of the previous epoch, the carrier phase change between epochs is determined; based on the carrier phase noise of the current epoch and the carrier phase noise of the previous epoch, the carrier phase noise change between epochs is determined; based on the carrier phase wavelength, the carrier phase change between epochs, the satellite clock error change between epochs, the carrier phase noise change between epochs, the GNSS receiver clock error change between epochs, the satellite position change between epochs, and the position change of the current epoch, the carrier phase epoch difference equation is constructed.

[0107] In this embodiment of the present invention, when constructing the carrier phase inter-epoch differential equation, the carrier phase noise of the current epoch and the carrier phase noise of the previous epoch are obtained from the GNSS observations of the current epoch and the GNSS observations of the previous epoch, respectively, and the carrier phase noise variation between epochs is calculated. The carrier phase inter-epoch differential equation constructed based on the carrier phase noise variation between epochs is expressed as:

[0108]

[0109] in, is the carrier phase noise variation between epochs.

[0110] As an implementation method, the least squares method is used to solve the carrier phase epoch difference equation to obtain a first solution result; however, the least squares method involves multiplication and inversion operations of large matrices, which will consume more computing power of the GNSS receiver.

[0111] As another implementation method, the carrier phase epoch-to-epoch differential equation is solved using an observation-by-observation filtering method (such as a Kalman filter) to obtain a first solution result. This can greatly improve the solution efficiency and reduce the computing power consumption of the GNSS receiver.

[0112] Optionally, in practical applications, if positioning using the carrier phase inter-epoch differential equation alone fails, a Doppler observation equation is constructed and used simultaneously for positioning, thereby optimizing the GNSS positioning process. The raw GNSS observations also include Doppler and Doppler noise, and the first solution results include the position change of the current epoch, the change in the GNSS receiver clock error between epochs, and the target carrier phase quantity. Figure 2 The sub-steps of step S50 may include:

[0113] The carrier phase post-validation residual corresponding to the target carrier phase is determined based on the inter-epoch carrier phase change, the inter-epoch satellite position change, the current epoch position change, and the inter-epoch GNSS receiver clock error change. When the carrier phase post-validation residual satisfies the chi-square test, it is determined whether the number of target carrier phases exceeds the preset carrier phase number threshold. If so, positioning is successful. If not, the Doppler observation is determined based on the target Doppler and the corresponding previous epoch Doppler. The inter-epoch Doppler noise change is determined based on the current epoch Doppler noise and the previous epoch Doppler noise. The Doppler observation equation is constructed based on the Doppler observation, the inter-epoch time interval, the carrier phase wavelength, the inter-epoch satellite clock error change, the inter-epoch Doppler noise change, the inter-epoch GNSS receiver clock error change, the inter-epoch satellite position change, and the current epoch position change.

[0114] In this embodiment of the present invention, the calculation formula of the carrier phase post-verification residual is expressed as:

[0115]

[0116] in, is the carrier phase post-verification residual. For ease of description, take the signal frequency i = 1 as an example. Assuming that the number of target carrier phases is n, the carrier phase chi-square test quantity is constructed based on the n carrier phase post-verification residuals and the corresponding preset carrier phase weights. The carrier phase chi-square test quantity expression can be:

[0117]

[0118] Among them, chiTest is the carrier phase chi-square test, is the j-th carrier phase post-verification residual, is the preset carrier phase weight corresponding to the j-th carrier phase post-verification residual; sigma0 is a constant. In order to ensure that the value of sigma0 is not affected by abnormal observations, sigma0 can be set to 0.05 meters.

[0119] When the carrier phase chi-square test value is less than the preset carrier phase chi-square threshold, the carrier phase post-test residual is considered to meet the chi-square test, indicating that the target carrier phase does not contain outliers. The current target carrier phase quantity is determined to see if it meets the preset carrier phase quantity threshold. If the target carrier phase quantity on which positioning depends exceeds the preset carrier phase quantity threshold, positioning is successful. In other words, the first solution result indicates successful positioning. The absolute position of the current epoch is obtained by summing the GNSS receiver position in the previous epoch and the position change in the current epoch in the first solution result. The absolute position of the current epoch is the GNSS receiver position in the current epoch.

[0120] When the number of target carrier phases that positioning depends on does not exceed the preset carrier phase number threshold, it means that the positioning result obtained using the target carrier phase may be inaccurate, which will affect the GNSS positioning result. It means that the first solution result represents a positioning failure, so it is necessary to construct a Doppler observation equation.

[0121] In an embodiment of the present invention, the Doppler observation equation is expressed as:

[0122]

[0123] in, is the Doppler observation, and its value can be the average of the target Doppler and the Doppler of the previous epoch; is the Doppler noise variation between epochs.

[0124] Optionally, in practical applications, when there is a gross error in the target carrier phase, outliers are eliminated through robust estimation to ensure the accuracy of GNSS positioning. The GNSS positioning method further includes the following steps:

[0125] When the carrier phase post-validation residual does not satisfy the chi-square test, the corresponding standardized carrier phase residual is obtained based on the carrier phase post-validation residual; the weight of the target carrier phase is updated according to the value range of each standardized carrier phase residual; the carrier phase with a target carrier phase weight of 0 is eliminated to obtain the updated target carrier phase, so that the carrier phase inter-epoch difference equation can be resolved based on the updated target carrier phase.

[0126] In this embodiment of the present invention, if the carrier phase post-verification residual is not less than a preset carrier phase chi-square threshold, the carrier phase post-verification residual is considered to fail the chi-square test, indicating that an outlier exists in the target carrier phase and needs to be identified. The carrier phase post-verification residual is processed to obtain a normalized carrier phase residual.

[0127] In order to reduce the impact of gross errors on GNSS positioning accuracy, a robust estimation method is used to identify target carrier phase outliers. The carrier phase weight function used in the robust estimation can be expressed as:

[0128]

[0129] in, is the weight of the target carrier phase obtained after weight selection iteration, is the jth normalized carrier phase residual in signal frequency i, is the preset carrier phase weight corresponding to the j-th carrier phase post-validation residual in signal frequency i; k0 and k1 are constants and can be set according to actual application, for example, k0 is 1 and k1 is 0.5.

[0130] After the robustness estimation is completed, the target carrier phase with a weight of 0 is eliminated to obtain an updated target carrier phase, and the updated target carrier phase returns to execute step S20, and the next round of GNSS positioning is performed according to the updated target carrier phase.

[0131] Optionally, in practical applications, when positioning fails using both the carrier phase inter-epoch differential equation and the Doppler observation equation, a pseudorange inter-epoch differential equation is constructed, and positioning is then performed using the carrier phase inter-epoch differential equation, the Doppler observation equation, and the pseudorange inter-epoch differential equation simultaneously, thereby achieving inter-epoch differential positioning that adaptively integrates multiple types of observations. The raw GNSS observations also include pseudoranges and pseudorange noise, and the second solution results include the position change of the current epoch, the change in the GNSS receiver clock error between epochs, the target carrier phase quantity, and the target Doppler quantity. Figure 2 The sub-steps of step S80 may include:

[0132] The Doppler post-verification residual corresponding to the target Doppler is determined based on the Doppler observation, the inter-epoch satellite position change, the position change of the current epoch, and the inter-epoch GNSS receiver clock error change. When both the carrier phase post-verification residual and the Doppler post-verification residual satisfy the chi-square test, it is determined whether the target carrier phase number exceeds the preset carrier phase number threshold and whether the target Doppler number exceeds the preset Doppler number threshold. If so, positioning is successful. If not, the inter-epoch pseudorange change is determined based on the target pseudorange and the corresponding pseudorange of the previous epoch. The inter-epoch pseudorange noise change is determined based on the pseudorange noise of the current epoch and the pseudorange noise of the previous epoch. The inter-epoch pseudorange epoch difference equation is constructed based on the inter-epoch pseudorange change, the inter-epoch satellite clock error change, the inter-epoch pseudorange noise change, the inter-epoch GNSS receiver clock error change, the inter-epoch satellite position change, and the position change of the current epoch.

[0133] In the embodiment of the present invention, the calculation formula of the Doppler post-test residual is expressed as:

[0134]

[0135] in, The basic principles for constructing the Doppler chi-square test value and the Doppler weight function are the same as those for the carrier phase chi-square test value and the carrier phase weight function. For the sake of simplicity, the expressions of the Doppler chi-square test value and the Doppler weight function are not repeated here. Please refer to the corresponding contents in the above embodiments.

[0136] When the carrier phase post-verification residual is less than the preset carrier phase chi-square threshold and the Doppler post-verification residual is less than the preset Doppler chi-square threshold, it is considered that both the carrier phase post-verification residual and the Doppler post-verification residual meet the chi-square test, indicating that the target carrier phase and target Doppler do not contain outliers. It is judged whether the target carrier phase number exceeds the preset carrier phase number threshold and whether the target Doppler number exceeds the preset Doppler number threshold.

[0137] If the number of target carrier phases that the positioning depends on exceeds the preset carrier phase number threshold and the target Doppler number exceeds the preset Doppler number threshold, it means that the positioning is successful. In other words, the second settlement result represents the successful positioning. The absolute position of the current epoch is obtained based on the sum of the GNSS receiver position of the previous epoch and the position change of the current epoch in the second solution result.

[0138] When the number of target carrier phases on which positioning depends does not exceed the preset carrier phase number threshold or the target Doppler number does not exceed the preset Doppler number threshold, it means that the positioning result obtained using the target carrier phase and target Doppler may be inaccurate, indicating that the second solution result represents a positioning failure, and therefore it is necessary to construct a differential equation between pseudorange epochs.

[0139] In the embodiment of the present invention, the pseudorange epoch difference equation is expressed as:

[0140]

[0141] in, is the variation of pseudorange noise between epochs.

[0142] When judging the third solution result, the basic principles for constructing the pseudorange phase post-verification residual, pseudorange chi-square test value, and pseudorange weight function are the same as those for the carrier phase. For the sake of simplicity, they are not repeated here. Please refer to the corresponding content in the embodiment of the carrier phase.

[0143] It should be noted that if robust estimation still fails to eliminate abnormal observations, it may be that the positioning system as a whole is abnormal, such as in the Beidou or Galileo positioning systems. The GNSS raw observations from the faulty positioning system are then eliminated, and GNSS positioning is performed again starting from step S10 based on the eliminated GNSS raw observations.

[0144] Optionally, in practical applications, positioning accuracy based on carrier phase is the highest, followed by Doppler, and the worst is pseudorange. The frequency weight of each signal frequency is determined by the number of target carrier phases, target Dopplers, and target pseudoranges corresponding to each signal frequency. GNSS positioning is performed using the target carrier phase, target Doppler, and target pseudorange of the corresponding signal frequency in descending order of frequency weight. This can effectively improve positioning accuracy and efficiency, and can improve the real-time, robustness, and accuracy of GNSS positioning. Figure 2 After step S10, the GNSS positioning method further includes the following steps:

[0145] The frequency weights are derived based on the number of target carrier phases, target Dopplers, and target pseudoranges for each signal frequency. Each time, the corresponding target signal frequency is determined in descending order of frequency weights, allowing GNSS positioning to be performed based on the target carrier phase, target Doppler, and target pseudorange corresponding to the target signal frequency.

[0146] In the embodiment of the present invention, the calculation formula of the frequency weight is:

[0147] C i,all =aC i,cp +bC i,dr +cC i,pr

[0148] Among them, C i,all is the frequency weight of signal frequency i; C i,cp is the target carrier phase number corresponding to signal frequency i; C i,dr is the target Doppler number corresponding to signal frequency i; C i,pris the number of target pseudoranges corresponding to signal frequency i; a, b, and c are constants and can be set according to actual applications. For example, a, b, and c can be set to 10, 2, and 1, respectively.

[0149] Determine a target signal frequency in descending order of frequency weight, obtain a target carrier phase, target Doppler, and target pseudorange corresponding to the target signal frequency, and execute steps S10 to S90 according to the target carrier phase, target Doppler, and target pseudorange corresponding to the target signal frequency. If GNSS positioning fails according to the target carrier phase, target Doppler, and target pseudorange corresponding to the current target signal frequency, iteratively obtain the target carrier phase, target Doppler, and target pseudorange with a suboptimal frequency weight, and repeat steps S10 to S90 until positioning succeeds or fails.

[0150] Based on the same inventive concept, an embodiment of the present invention further provides a GNSS device. The basic principles and technical effects thereof are the same as those of the above embodiment. For the sake of brevity, for parts not mentioned in this embodiment, reference may be made to the corresponding contents of the above embodiment.

[0151] Please refer to Figure 3 , Figure 3 FIG2 is a block diagram of a GNSS positioning device 300 according to an embodiment of the present invention. The GNSS positioning device 300 includes a pre-processing module 301 and a positioning module 302 .

[0152] A preprocessing module 301 is configured to determine a target carrier phase, a target Doppler, and a target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch;

[0153] The positioning module 302 is configured to obtain a carrier phase inter-epoch differential equation based on the target carrier phase, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; solve the carrier phase inter-epoch differential equation to obtain a first solution result; if the first solution result indicates that positioning is successful, obtain the absolute position of the current epoch based on the first solution result; if the first solution result indicates that positioning is unsuccessful, obtain the Doppler observation equation based on the target Doppler, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; solve the carrier phase inter-epoch differential equation to obtain the absolute position of the current epoch ... The second solution result is obtained by solving the differential equation and the Doppler observation equation; if the second solution result indicates that positioning is successful, the absolute position of the current epoch is obtained according to the second solution result; if the second solution result indicates that positioning is unsuccessful, the differential equation between pseudorange epochs is obtained according to the target pseudorange, the GNSS raw observation value of the previous epoch, the ephemeris of the current epoch and the ephemeris of the previous epoch; the differential equation between carrier phase epochs, the Doppler observation equation and the differential equation between pseudorange epochs are solved to obtain the third solution result; if the third solution result indicates that positioning is successful, the absolute position of the current epoch is obtained according to the third solution result.

[0154] In summary, the GNSS device provided in the embodiment of the present invention uses the GNSS raw observations and ephemeris between adjacent epochs to perform differential navigation positioning. First, a carrier phase differential equation between epochs is constructed, and the success of the positioning is determined based on the first solution result obtained by solving the carrier phase differential equation between epochs. If the positioning is successful, the absolute position of the GNSS receiver in the current epoch is directly determined based on the first solution result.

[0155] If positioning fails, continue to construct the Doppler observation equation, and simultaneously solve the carrier phase epoch differential equation and the Doppler observation equation to obtain a second solution result, and judge whether the positioning is successful based on the second solution result. If positioning is successful, directly determine the absolute position of the current epoch of the GNSS receiver based on the second solution result; if positioning fails, continue to construct the pseudorange epoch differential equation, and simultaneously solve the carrier phase epoch differential equation, the Doppler observation equation and the pseudorange epoch differential equation to obtain a third solution result, and perform GNSS positioning based on the third solution result.

[0156] The present invention realizes inter-epoch differential positioning by adaptively fusing carrier phase, Doppler and pseudorange, thereby effectively improving the efficiency, accuracy and robustness of GNSS positioning, while also improving the success rate of constructing the carrier phase inter-epoch differential equation, the Doppler observation equation and the pseudorange inter-epoch differential equation.

[0157] In addition, since the GNSS positioning device provided by the embodiment of the present invention can effectively improve the efficiency and accuracy of GNSS positioning, it effectively reduces the requirements for the precision of the GNSS receiver. A low-cost GNSS receiver can be used in complex environments to implement the GNSS positioning device provided by the embodiment of the present invention, which can effectively reduce the cost of GNSS positioning, thereby improving the practicality of low-cost GNSS receivers in application scenarios such as autonomous driving, agricultural machinery autonomous driving, and artificial intelligence.

[0158] Optionally, the preprocessing module 301 is specifically used to determine the satellite elevation angles of all satellites based on the GNSS raw observations of the current epoch; determine the satellites whose satellite elevation angles exceed the preset elevation angles as candidate satellites; determine the GNSS raw observations of the current epoch in which the candidate satellites do not have a cycle slip as preliminary observations; determine the same observations in the GNSS raw observations of the previous epoch and the preliminary observations as candidate observations; eliminate abnormal observations from the candidate observations based on the estimated value of the GNSS receiver clock error change to obtain the target carrier phase, target Doppler and target pseudorange.

[0159] Optionally, the GNSS raw observations include carrier phase and carrier phase noise.

[0160] The positioning module 302 is specifically used to determine the satellite position change between epochs and the satellite clock error change between epochs based on the ephemeris of the current epoch and the ephemeris of the previous epoch; determine the carrier phase change between epochs based on the target carrier phase and the carrier phase of the corresponding previous epoch; determine the carrier phase noise change between epochs based on the carrier phase noise of the current epoch and the carrier phase noise of the previous epoch; and construct a carrier phase epoch difference equation based on the carrier phase wavelength, the carrier phase change between epochs, the satellite clock error change between epochs, the carrier phase noise change between epochs, the GNSS receiver clock error change between epochs, the satellite position change between epochs, and the position change of the current epoch.

[0161] Optionally, the GNSS raw observations also include Doppler and Doppler noise, and the first solution result includes the position change of the current epoch, the GNSS receiver clock error change between epochs, and the target carrier phase quantity.

[0162] The positioning module 302 is specifically used to determine the carrier phase post-verification residual corresponding to the target carrier phase based on the carrier phase change between epochs, the satellite position change between epochs, the position change of the current epoch, and the GNSS receiver clock error change between epochs; when the carrier phase post-verification residual satisfies the chi-square test, it is determined whether the number of target carrier phases exceeds a preset carrier phase number threshold. If so, positioning is successful; if not, the Doppler observation amount is determined based on the target Doppler and the Doppler of the corresponding previous epoch, the Doppler noise change between epochs is determined based on the Doppler noise of the current epoch and the Doppler noise of the previous epoch, and the Doppler observation equation is constructed based on the Doppler observation amount, the time interval between epochs, the carrier phase wavelength, the satellite clock error change between epochs, the Doppler noise change between epochs, the GNSS receiver clock error change between epochs, the satellite position change between epochs, and the position change of the current epoch.

[0163] Optionally, the positioning module 302 is specifically used to obtain a corresponding standardized carrier phase residual based on the carrier phase post-verification residual when the carrier phase post-verification residual does not satisfy the chi-square test; update the weight of the target carrier phase according to the value range of each standardized carrier phase residual; eliminate the carrier phase with a target carrier phase weight of 0 to obtain an updated target carrier phase, so as to re-solve the carrier phase inter-epoch difference equation based on the updated target carrier phase.

[0164] Optionally, the GNSS original observation quantity also includes pseudorange and pseudorange noise, and the second solution result includes the position change of the current epoch, the GNSS receiver clock error change between epochs, the target carrier phase quantity and the target Doppler quantity.

[0165] The positioning module 302 is specifically configured to determine the Doppler post-verification residual corresponding to the target Doppler based on the Doppler observation, the satellite position change between epochs, the position change of the current epoch, and the GNSS receiver clock error change between epochs. When both the carrier phase post-verification residual and the Doppler post-verification residual satisfy the chi-square test, it is determined whether the number of target carrier phases exceeds a preset carrier phase number threshold and whether the number of target Dopplers exceeds a preset Doppler number threshold. If so, positioning is successful. If not, the inter-epoch pseudorange change is determined based on the target pseudorange and the corresponding pseudorange of the previous epoch, the inter-epoch pseudorange noise change is determined based on the pseudorange noise of the current epoch and the pseudorange noise of the previous epoch, and the inter-epoch pseudorange epoch difference equation is constructed based on the inter-epoch pseudorange change, the inter-epoch satellite clock error change, the inter-epoch pseudorange noise change, the inter-epoch GNSS receiver clock error change, the inter-epoch satellite position change, and the position change of the current epoch.

[0166] Optionally, the positioning module 302 is further used to obtain a corresponding frequency weight based on the number of target carrier phases, target Dopplers, and target pseudoranges in each signal frequency; each time, a corresponding target signal frequency is determined in descending order of the frequency weights, so as to perform GNSS positioning based on the target carrier phase, target Doppler, and target pseudorange corresponding to the target signal frequency.

[0167] Please refer to Figure 4 , Figure 4 This is a block diagram of a GNSS receiver 100 according to an embodiment of the present invention. GNSS receiver 100 includes a memory 110, a processor 120, and a communication module 130. The memory 110, processor 120, and communication module 130 are electrically connected to each other, directly or indirectly, to enable data transmission or exchange. For example, these components may be electrically connected via one or more communication buses or signal lines.

[0168] Memory 110 is used to store programs or data. Memory 110 may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.

[0169] The processor 120 is used to read / write data or programs stored in the memory 110 and execute corresponding functions. For example, when the computer program stored in the memory 110 is executed by the processor 120, the GNSS positioning method disclosed in the above embodiments can be implemented.

[0170] The communication module 130 is used to establish a communication connection between the GNSS receiver 100 and other communication terminals through a network, and to send and receive data through the network.

[0171] It should be understood that Figure 4 The structure shown is only a schematic diagram of the structure of the GNSS receiver 100. The GNSS receiver 100 may also include Figure 4 More or fewer components than shown, or with Figure 4 Different configurations shown. Figure 4 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0172] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by the processor 120, the GNSS positioning method disclosed in the above embodiments is implemented.

[0173] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of the devices, methods, and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, which contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the boxes can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, as well as the combination of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified functions or actions, or can be implemented using a combination of dedicated hardware and computer instructions.

[0174] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0175] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0176] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A GNSS positioning method, characterized in that: Applied to a GNSS receiver, the method comprises: Determine the target carrier phase, target Doppler, and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch; Obtaining a carrier phase inter-epoch differential equation based on the target carrier phase, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; Solving the carrier phase inter-epoch differential equation to obtain a first solution result; if the first solution result indicates successful positioning, obtaining the absolute position of the current epoch based on the first solution result; if the first solution result indicates a positioning failure, obtaining a Doppler observation equation based on the target Doppler, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; Solving the carrier phase epoch-to-epoch differential equation and the Doppler observation equation to obtain a second solution result; if the second solution result indicates successful positioning, obtaining the absolute position of the current epoch according to the second solution result; if the second solution result indicates a positioning failure, obtaining the pseudorange-to-epoch differential equation according to the target pseudorange, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; Solving the carrier phase epoch differential equation, the Doppler observation equation, and the pseudorange epoch differential equation to obtain a third solution result; if the third solution result indicates successful positioning, obtaining the absolute position of the current epoch according to the third solution result.

2. The GNSS positioning method according to claim 1, wherein: The determining of the target carrier phase, target Doppler, and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch includes: Determine the satellite elevation angles of all satellites based on the GNSS raw observations of the current epoch; Determine the satellite whose elevation angle exceeds the preset elevation angle as a candidate satellite; Determine the GNSS raw observations of the current epoch in which the candidate satellite does not have a cycle slip as the primary observations; Determine the GNSS original observation of the previous epoch and the same observation in the preliminary selected observation as the candidate observation; Abnormal observation quantities are eliminated from the candidate observation quantities according to the estimated value of the GNSS receiver clock error variation to obtain the target carrier phase, the target Doppler, and the target pseudorange.

3. The GNSS positioning method according to claim 1, wherein: The GNSS raw observations include carrier phase and carrier phase noise; and the step of obtaining the carrier phase inter-epoch difference equation based on the target carrier phase, the GNSS raw observations of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch comprises: Determine the satellite position change between epochs and the satellite clock error change between epochs based on the ephemeris of the current epoch and the ephemeris of the previous epoch; Determining an inter-epoch carrier phase variation based on the target carrier phase and the corresponding carrier phase of the previous epoch; Determine the carrier phase noise variation between epochs based on the carrier phase noise of the current epoch and the carrier phase noise of the previous epoch; A carrier phase inter-epoch differential equation is constructed based on the carrier phase wavelength, the carrier phase change between epochs, the satellite clock error change between epochs, the carrier phase noise change between epochs, the GNSS receiver clock error change between epochs, the satellite position change between epochs, and the position change of the current epoch.

4. The GNSS positioning method according to claim 3, wherein: The GNSS raw observations also include Doppler and Doppler noise; the first solution result includes the position change of the current epoch, the GNSS receiver clock error change between the epochs, and the target carrier phase quantity; if the first solution result indicates positioning failure, the step of obtaining a Doppler observation equation based on the target Doppler, the GNSS raw observations of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch includes: Determining a carrier phase posterior-validation residual corresponding to the target carrier phase based on the inter-epoch carrier phase change, the inter-epoch satellite position change, the position change of the current epoch, and the inter-epoch GNSS receiver clock error change; When the carrier phase post-verification residual satisfies the chi-square test, it is determined whether the target carrier phase quantity exceeds a preset carrier phase quantity threshold, and if so, the positioning is successful; If not exceeded, a Doppler observation is determined according to the target Doppler and the Doppler of the corresponding previous epoch, and an inter-epoch Doppler noise variation is determined according to the Doppler noise of the current epoch and the Doppler noise of the previous epoch. A Doppler observation equation is constructed according to the Doppler observation, the inter-epoch time interval, the carrier phase wavelength, the inter-epoch satellite clock difference variation, the inter-epoch Doppler noise variation, the inter-epoch GNSS receiver clock difference variation, the inter-epoch satellite position variation, and the position change of the current epoch.

5. The GNSS positioning method according to claim 4, characterized in that: The method further comprises: When the carrier phase post-test residual does not satisfy the chi-square test, obtaining a corresponding normalized carrier phase residual according to the carrier phase post-test residual; Updating the weight of the target carrier phase according to the value range of each of the standardized carrier phase residuals; The carrier phases with a weight of 0 of the target carrier phase are eliminated to obtain an updated target carrier phase, so that the carrier phase inter-epoch difference equation is re-solved according to the updated target carrier phase.

6. The GNSS positioning method according to claim 4, characterized in that: The GNSS raw observations also include pseudoranges and pseudorange noises; the second solution result includes a position change of the current epoch, a GNSS receiver clock error change between epochs, a target carrier phase quantity, and a target Doppler quantity; if the second solution result indicates positioning failure, the step of obtaining a pseudorange-epoch difference equation based on the target pseudorange, the GNSS raw observations of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch comprises: Determining a Doppler posterior residual corresponding to the target Doppler based on the Doppler observation, the satellite position change between epochs, the position change of the current epoch, and the GNSS receiver clock difference change between epochs; When both the carrier phase post-test residual and the Doppler post-test residual satisfy the chi-square test, it is determined whether the target carrier phase number exceeds a preset carrier phase number threshold and whether the target Doppler number exceeds a preset Doppler number threshold, and if so, the positioning is successful; If it does not exceed, the inter-epoch pseudorange change is determined according to the target pseudorange and the corresponding pseudorange of the previous epoch, the inter-epoch pseudorange noise change is determined according to the pseudorange noise of the current epoch and the pseudorange noise of the previous epoch, and the inter-epoch pseudorange change, the inter-epoch satellite clock difference change, the inter-epoch pseudorange noise change, the inter-epoch GNSS receiver clock difference change, the inter-epoch satellite position change and the position change of the current epoch are used to construct a pseudorange inter-epoch differential equation.

7. The GNSS positioning method according to any one of claims 1 to 6, characterized in that: After determining the target carrier phase, target Doppler, and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch, the method further includes: According to the number of target carrier phases, target Dopplers and target pseudoranges in each signal frequency, the corresponding frequency weight is obtained; Each time, a corresponding target signal frequency is determined in descending order of frequency weights, so as to perform GNSS positioning according to the target carrier phase, target Doppler and target pseudorange corresponding to the target signal frequency.

8. A GNSS positioning device, characterized in that: Applied to a GNSS receiver, the device comprises: A preprocessing module is used to determine the target carrier phase, target Doppler and target pseudorange based on the GNSS raw observations of the current epoch and the GNSS raw observations of the previous epoch; A positioning module is configured to obtain a carrier phase inter-epoch differential equation based on the target carrier phase, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; solve the carrier phase inter-epoch differential equation to obtain a first solution result; if the first solution result indicates a successful positioning, obtain the absolute position of the current epoch based on the first solution result; if the first solution result indicates a failed positioning, obtain a Doppler observation equation based on the target Doppler, the GNSS raw observation of the previous epoch, the ephemeris of the current epoch, and the ephemeris of the previous epoch; solve the carrier phase inter-epoch differential equation and the Doppler observation equation to obtain a second solution result; if the second solution result indicates that positioning is successful, the absolute position of the current epoch is obtained according to the second solution result; if the second solution result indicates that positioning fails, the pseudorange epoch difference equation is obtained according to the target pseudorange, the GNSS original observation of the previous epoch, the ephemeris of the current epoch and the ephemeris of the previous epoch; the carrier phase epoch difference equation, the Doppler observation equation and the pseudorange epoch difference equation are solved to obtain a third solution result; if the third solution result indicates that positioning is successful, the absolute position of the current epoch is obtained according to the third solution result.

9. A GNSS receiver, characterized in that: The system comprises a processor and a memory, wherein the memory stores machine-executable instructions that can be executed by the processor, and the processor can execute the machine-executable instructions to implement the GNSS positioning method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the GNSS positioning method according to any one of claims 1 to 7 is implemented.

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