GNSS standard single point positioning method and system based on subcarrier observation value reconstruction

Abstract

The invention provides a GNSS (Global Navigation Satellite System) standard single-point positioning method and system based on subcarrier observation value reconstruction, and belongs to the technical field of satellite navigation positioning. Reconstructing a subcarrier phase observation value, a carrier phase observation value and a pseudo-range observation value of the GNSS broadband signal in an observation domain, and performing quality control on the reconstructed subcarrier phase observation value; and estimating floating point ambiguity in the reconstructed subcarrier phase observation value, converting the reconstructed subcarrier phase observation value into absolute distance information according to the floating point ambiguity, carrying out standard single point positioning according to the absolute distance information, and outputting receiver position information. Under the existing mainstream baseband tracking loop framework, the GNSS standard single-point positioning performance can be improved, the large-scale application and popularization difficulty of the subcarrier positioning technology can be effectively reduced, and the method has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation and positioning technology, and in particular to a GNSS standard single-point positioning method and system based on subcarrier observation reconstruction. Background Technology

[0002] As a critical spatiotemporal information infrastructure with global coverage, all-day, all-weather positioning, navigation, and timing (PNT) capabilities, the Global Navigation Satellite System (GNSS) is continuously driving numerous industries towards automation and intelligence. In the modernization of GNSS, to improve spectrum resource utilization efficiency and enhance compatibility and interoperability between different systems, next-generation GNSS signals widely employ wideband subcarrier modulation technology. Typical examples include MBOC signals in the L1C / E1 / B1C bands, and E5 AltBOC, B2 ACE-BOC, and B1 SCBOC signals formed by merging adjacent frequency points. These wideband subcarrier modulated signals, with their large bandwidth characteristics, exhibit significant high-precision ranging potential in noisy, multipath, and interference environments. To overcome the inherent limitations of traditional pseudocode ranging signals, such as high noise and susceptibility to multipath effects, it is urgent to develop new processing methods that can efficiently extract and utilize high-precision subcarrier observations from wideband signals to further improve the single-point positioning performance of GNSS standards.

[0003] However, as the subcarrier order increases, the multi-peak structure of the autocorrelation function of the broadband subcarrier modulated signal becomes increasingly complex, leading to a sharp increase in processing difficulty and implementation complexity. Specifically, traditional one-dimensional tracking methods that treat pseudocode and subcarrier delay as common parameters for estimation face a more severe risk of subpeak locking, making it difficult to achieve robust and ambiguity-free tracking of broadband subcarrier modulated signals. Although existing two-dimensional tracking methods can fundamentally eliminate pseudocode tracking ambiguity by independently estimating pseudocode and subcarrier delay and generating independent subcarrier phase observations, these observations still contain unknown integer ambiguity and cannot be directly used for standard single-point positioning solutions. Moreover, the analysis of error characteristics and the research on correction models for broadband subcarrier observations are still incomplete, lacking a precise positioning model that can fully utilize its high-precision potential. Furthermore, if full-bandwidth reception and two-dimensional tracking of broadband signals are performed, the receiver will face extremely high front-end sampling rate requirements and real-time computational loads, and the baseband processing architecture needs to be reconstructed, thus significantly increasing the implementation difficulty and cost.

[0004] Therefore, how to stably generate high-precision subcarrier observations of broadband signals based on traditional or moderately improved tracking loop structures, and how to construct an effective positioning model to fully unleash its accuracy advantages, has become an important technical problem that urgently needs to be solved in the field of GNSS positioning. Summary of the Invention

[0005] This invention provides a GNSS standard point positioning method and system based on subcarrier observation reconstruction, which solves the defects of the existing GNSS standard point positioning method in terms of processing difficulty and implementation complexity, thereby reducing the difficulty of application and promotion of subcarrier positioning technology and improving the performance of GNSS standard point positioning.

[0006] In a first aspect, the present invention provides a GNSS standard point positioning method based on subcarrier observation reconstruction, comprising: Receive intermediate frequency data of GNSS broadband signal, track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generate pseudorange observation values ​​and carrier phase observation values ​​of the upper sideband signal and lower sideband signal respectively; Based on the carrier phase observations of the upper sideband signal and the lower sideband signal, the subcarrier phase observations and carrier phase observations of the GNSS broadband signal are reconstructed in the observation domain, and the pseudorange observations of the GNSS broadband signal are also reconstructed in the observation domain. Based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation, the quality control of the reconstructed subcarrier phase observation is performed. Based on the reconstructed pseudorange observations, the floating-point ambiguity in the reconstructed subcarrier phase observations is estimated. Based on the floating-point ambiguity, the reconstructed subcarrier phase observations are converted into absolute distance information. Standard point positioning is performed based on the absolute distance information, and receiver position information is output.

[0007] According to the present invention, a GNSS standard point positioning method based on subcarrier observation reconstruction is provided, wherein after receiving GNSS broadband signal intermediate frequency data, tracking the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generating pseudorange observations and carrier phase observations of the upper sideband signal and lower sideband signal respectively, the method further includes: Cycle slip test parameters are constructed by interepoch difference to detect cycle slips in the carrier phase observations of the upper sideband signal and the lower sideband signal, respectively. In the case of receiving a single-frequency GNSS broadband signal, the first-order difference between epochs of the carrier phase observations of the upper sideband signal and the second-order difference between epochs based on the Doppler integral are calculated respectively to construct the cycle slip test quantity. For the case of receiving multi-frequency GNSS broadband signals, the first-order difference between epochs of the MW combination and the first-order difference between epochs of the GF combination are calculated for the observation values ​​of the upper sideband signal / lower sideband signal of two of the GNSS broadband signals, and the cycle slip test quantity is constructed. If a cycle slip is detected, a cycle slip marker is created.

[0008] According to the present invention, a GNSS standard point positioning method based on subcarrier observation reconstruction is provided, wherein the subcarrier phase observation and carrier phase observation of the GNSS broadband signal are reconstructed in the observation domain based on the carrier phase observations of the upper sideband signal and the lower sideband signal, the method includes: Subtract the carrier phase observations of the upper sideband signal and the lower sideband signal, and then multiply by the subcarrier wavelength to obtain the subcarrier phase observation of the reconstructed GNSS broadband signal in the observation domain; add the carrier phase observations of the upper sideband signal and the lower sideband signal, and then multiply by the wavelength of the GNSS broadband signal to obtain the carrier phase observation of the reconstructed GNSS broadband signal in the observation domain.

[0009] According to the present invention, a GNSS standard point positioning method based on subcarrier observation reconstruction is provided, wherein reconstructing the pseudorange observations of the GNSS broadband signal in the observation domain includes: The pseudorange observations of the upper sideband signal and the lower sideband signal are power-weighted to obtain the pseudorange observations reconstructed from the GNSS broadband signal in the observation domain.

[0010] According to the present invention, a GNSS standard point positioning method based on subcarrier observation reconstruction includes, wherein the quality control of the reconstructed subcarrier phase observations based on the reconstructed subcarrier phase observations, the reconstructed carrier phase observations, and the reconstructed pseudorange observations includes: Calculate the first difference between the reconstructed pseudorange observation and the reconstructed subcarrier phase observation at the current epoch, and the second difference between the reconstructed carrier phase observation and the reconstructed subcarrier phase observation. The first difference and the second difference are respectively subjected to epoch-time difference to form two subcarrier cycle slip test quantities; The reconstructed subcarrier phase observation is cycle-slip detected based on the two subcarrier cycle slip test values. If a cycle slip is detected, an integer cycle slip is estimated, and the reconstructed subcarrier phase observation is cycle-slip repaired based on the integer cycle slip.

[0011] According to the present invention, a GNSS standard point positioning method based on subcarrier observation reconstruction is provided, wherein estimating the floating-point ambiguity in the reconstructed subcarrier phase observation based on the reconstructed pseudorange observation includes: The satellite-end hardware bias correction value is corrected in the reconstructed pseudorange observation value by using the pseudorange hardware bias correction value demodulated from the navigation message. Calculate the third difference between the reconstructed pseudorange observation correction value and the reconstructed subcarrier phase observation value. Within a preset time window, take the average value of the third difference as the floating-point ambiguity of the reconstructed subcarrier phase observation value.

[0012] According to the present invention, a GNSS standard point positioning method based on subcarrier observation reconstruction is provided. The process of converting the reconstructed subcarrier phase observations into absolute distance information based on the floating-point ambiguity, performing standard point positioning based on the absolute distance information, and outputting receiver position information includes: The reconstructed subcarrier phase observations are added to the floating-point ambiguity to obtain the absolute distance information; By combining satellite ephemeris and atmospheric delay models, satellite orbital errors, satellite clock errors, ionospheric delays, and tropospheric delays in the absolute distance information are corrected, and receiver position information is estimated.

[0013] Secondly, the present invention also provides a GNSS standard point positioning system based on subcarrier observation reconstruction, comprising: The sideband observation generation module is used to receive intermediate frequency data of GNSS broadband signal, track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generate pseudorange observations and carrier phase observations of the upper sideband signal and lower sideband signal respectively. The broadband observation reconstruction module is used to reconstruct the subcarrier phase observation and carrier phase observation of the GNSS broadband signal in the observation domain based on the carrier phase observations of the upper sideband signal and the lower sideband signal, and to reconstruct the pseudorange observation of the GNSS broadband signal in the observation domain; and to perform quality control on the reconstructed subcarrier phase observation based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation. The subcarrier positioning module is used to estimate the floating-point ambiguity in the reconstructed subcarrier phase observations based on the reconstructed pseudorange observations, convert the reconstructed subcarrier phase observations into absolute distance information based on the floating-point ambiguity, perform standard single-point positioning based on the absolute distance information, and output receiver position information.

[0014] Thirdly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the GNSS standard point positioning method based on subcarrier observation reconstruction as described above.

[0015] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the GNSS standard point positioning method based on subcarrier observation reconstruction as described above.

[0016] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the GNSS standard point positioning method based on subcarrier observation reconstruction as described above.

[0017] The beneficial effects of the technical solutions provided by some embodiments of the present invention include at least the following: 1) The present invention provides a GNSS standard point positioning method and system based on subcarrier observation reconstruction. By tracking the upper sideband signal and the lower sideband signal of the GNSS broadband signal respectively, the sideband observations are obtained, and the observations of the GNSS broadband signal are reconstructed based on the sideband observations. Without the need for a complete reconstruction of the receiver baseband processing architecture, GNSS standard point positioning based on subcarrier observation reconstruction can be achieved. This can reduce the complexity of GNSS broadband signal processing, improve the performance of GNSS standard point positioning, and reduce the difficulty of application and promotion of subcarrier positioning technology.

[0018] 2) This invention utilizes pseudorange observations and carrier phase observations of the upper and lower sideband signals to reconstruct the carrier phase observations, subcarrier phase observations, and pseudorange observations of the GNSS broadband signal in the observation domain. This maximizes the extraction and utilization of key information contained in the broadband signal, enabling fast, reliable, and high-precision positioning, which is beneficial for improving the reliability of standard single-point positioning.

[0019] 3) By introducing a quality control mechanism, this invention performs cycle slip detection and cycle slip repair on the carrier phase observations and reconstructed subcarrier phase observations of the sideband signal, respectively, thereby obtaining continuous reconstructed subcarrier phase observations without cycle slips, ensuring the continuity and reliability of the reconstructed subcarrier phase observations.

[0020] 4) This invention utilizes existing mature pseudorange bias products to design a method for correcting subcarrier observation bias and calculating floating-point ambiguity. It does not require upgrading the ground GNSS infrastructure to generate the corresponding subcarrier bias products, thereby significantly reducing the difficulty of large-scale application and promotion of subcarrier positioning technology. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is one of the flowcharts of a GNSS standard point positioning method based on subcarrier observation reconstruction provided by the present invention; Figure 2 This is the second flowchart of a GNSS standard point positioning method based on subcarrier observation reconstruction provided by the present invention; Figure 3 This is a schematic diagram of the structure of a GNSS standard point positioning system based on subcarrier observation reconstruction provided by the present invention; Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] Example 1 Please see Figure 1 , Figure 1 One of the flowcharts for a GNSS standard point positioning method based on subcarrier observation reconstruction provided as an embodiment of the present invention includes: S101. Receive GNSS broadband signal intermediate frequency data, track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generate pseudorange observation values ​​and carrier phase observation values ​​of the upper sideband signal and lower sideband signal respectively. S102. Based on the carrier phase observations of the upper sideband signal and the lower sideband signal, reconstruct the subcarrier phase observations and carrier phase observations of the GNSS broadband signal in the observation domain, and reconstruct the pseudorange observations of the GNSS broadband signal in the observation domain. S103. Based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation, perform quality control on the reconstructed subcarrier phase observation. S104. Based on the reconstructed pseudorange observations, estimate the floating-point ambiguity in the reconstructed subcarrier phase observations. Based on the floating-point ambiguity, convert the reconstructed subcarrier phase observations into absolute range information. Based on the absolute range information, perform standard single-point positioning and output the receiver position information.

[0025] This invention obtains sideband observations by tracking the upper and lower sideband signals of a GNSS broadband signal, and reconstructs the observations of the GNSS broadband signal based on the sideband observations. This achieves GNSS standard point positioning based on subcarrier observation reconstruction without completely reconstructing the receiver baseband processing architecture. This reduces the complexity of GNSS broadband signal processing, improves the performance of GNSS standard point positioning, and reduces the difficulty of applying and promoting subcarrier positioning technology.

[0026] In S101 of this embodiment, the receiver receives intermediate frequency data of GNSS broadband signal and uses a tracking loop composed of code loop and carrier loop to track the upper and lower sideband signal components of GNSS broadband signal respectively, generating pseudorange observations and carrier phase observations of the upper sideband signal, pseudorange observations and carrier phase observations of the lower sideband signal, etc.

[0027] It is understandable that GNSS broadband signals refer to modern GNSS signals that use subcarrier modulation technology. This includes signals such as MBOC signals at a single frequency point, as well as AltBOC, ACE-BOC, and SCBOC signals formed by the combination of multiple signal components at adjacent frequency points within the same frequency band.

[0028] In some possible embodiments, the upper sideband signal and lower sideband signal of the GNSS broadband signal are tracked separately, and pseudorange observations and carrier phase observations of the upper sideband signal and lower sideband signal are generated respectively, including: S101-1. Track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively according to the tracking loop composed of code ring and carrier ring; S101-2. Based on the satellite signal transmission time obtained by demodulation from the satellite navigation messages of the upper sideband signal and the lower sideband signal, and the reception time corresponding to the receiver's local clock, generate pseudorange observation values ​​for the upper sideband signal and the lower sideband signal respectively. S101-3. Based on the accumulated information of the integer and fractional parts of the carrier phase of the upper sideband signal and the lower sideband signal recorded in the carrier NCO register in the receiver, generate the carrier phase observation values ​​of the upper sideband signal and the lower sideband signal respectively.

[0029] Specifically, S101-1 is the upper and lower sideband tracking step for wideband signals: GNSS wideband signal intermediate frequency data, as well as the local copy code signals and carrier signals of the upper and lower sidebands, are acquired from the receiver. Correlation operations are performed to obtain the correlation results of the upper and lower sidebands, which are used to measure the degree of matching between the local copy code signals and carrier signals and the input intermediate frequency data. Based on the correlation results of the upper and lower sidebands, the code phase discriminator and carrier phase discriminator in the tracking loop are used to calculate the code phase error and carrier phase error of the upper and lower sidebands, respectively, and noise is filtered out by a low-pass filter. Based on the output of the low-pass filter, the code phase and Doppler frequency of the current tracking loop update cycle are estimated and used as input to drive the pseudo-code NCO of the upper and lower sidebands and the carrier NCO, generating the local copy code signal and carrier signal for the next loop update cycle.

[0030] S101-2 is the step for generating pseudorange observations in the sideband: The transmission time of the satellite transmitting this range code signal and the reception time of the receiver's local clock when the receiver receives this range code signal can be obtained from the satellite navigation message. Based on the clock difference between the transmission time and the reception time, pseudorange observations of the upper sideband signal and the lower sideband signal are generated respectively. S101-3 describes the steps for generating sideband carrier phase observations: The carrier NCO (Numerically Controlled Oscillator) register is an accumulator that increments with each sampling clock or system clock cycle. The highest few bits of the carrier NCO register, i.e., the integer part of the carrier phase, record the number of times the NCO phase accumulator overflows. Each overflow represents the completion of a complete cycle of the locally replicated carrier signal. The remaining low bits of the register, i.e., the fractional part, represent the proportion of phase completed within the current cycle. The phase value accumulated in the NCO register is equivalent to the total phase path traversed by the receiver to match the input signal phase. Therefore, by combining the accumulated information of the integer and fractional parts of the carrier phase recorded in the upper and lower sideband carrier NCO registers to form the total phase, and then converting it to distance units, the carrier phase observations of the upper and lower sideband signals can be generated.

[0031] In some possible embodiments, after receiving GNSS broadband signal intermediate frequency data, tracking the upper sideband and lower sideband signals of the GNSS broadband signal respectively, and generating pseudorange observations and carrier phase observations for the upper sideband and lower sideband signals respectively, the method further includes: Cycle slip test parameters are constructed by interepoch difference to detect cycle slips in the carrier phase observations of the upper sideband signal and the lower sideband signal, respectively. If a cycle slip is detected, it will be marked, and subsequent cycle slip observations will not be used.

[0032] Specifically, for the case of receiving single-frequency GNSS broadband signals, the first-order difference between epochs and the second-order difference between epochs based on Doppler integrals of the carrier phase observations of the upper sideband signal and the lower sideband signal are calculated as cycle slip test quantities to detect cycle slips in the carrier phase observations of the upper sideband signal and the lower sideband signal, respectively:

[0033] in, For the first Cycle slip test of each epoch. These are the upper sideband signal and the lower sideband signal, respectively. The carrier phase of the k-1th epoch, These are the upper sideband signal and the lower sideband signal, respectively. Doppler frequency observations at the k-th and (k-1)th epochs This represents the time interval between epochs. If... If the value exceeds the first preset threshold, a cycle slip is determined to have occurred.

[0034] For receiving multi-frequency GNSS broadband signals, the first-order difference between epochs of the Melbourne-Wübbena Combination is calculated for the observations of the upper sideband and lower sideband signals of two GNSS broadband signals, respectively, as a cycle slip test metric to detect cycle slips in the carrier phase observations of the upper and lower sideband signals of the multi-frequency GNSS broadband signal:

[0035] in, For MW combination number Cycle slip test of each epoch. and They are the first Carrier phase observations at frequency points 1 and 2 of each epoch. They are the first Carrier phase observations at frequency points 1 and 2 of each epoch; and They are the first pseudorange observations at frequency points 1 and 2 of each epoch. and They are the first Pseudorange observations at frequency points 1 and 2 of each epoch; and These are the center frequencies of frequency point 1 and frequency point 2, respectively. If If the value exceeds the second preset threshold, a cycle slip is determined to have occurred.

[0036] In addition to calculating the first-order difference between epochs of the MW combination for cycle slip detection, the first-order difference between epochs of the GF combination (Geometry-Free Combination) can also be calculated as a cycle slip check metric to detect cycle slips in the carrier phase observations of the upper and lower sideband signals of multi-frequency GNSS broadband signals.

[0037] in, For the GF combination Cycle slip test of each epoch. and These are the carrier wavelengths for frequency points 1 and 2, respectively. If... If the value exceeds the third preset threshold, a cycle slip is determined to have occurred.

[0038] For multi-frequency GNSS broadband signals, cycle slip detection can be performed by combining MW and GF combinations to comprehensively determine whether a cycle slip has occurred and ensure the accuracy of cycle slip detection.

[0039] In S102 of this embodiment, based on the carrier phase observation values ​​of the upper sideband signal and the lower sideband signal, the subcarrier phase observation value, carrier phase observation value, and pseudorange observation value of the GNSS broadband signal are reconstructed in the observation domain, and the reconstructed subcarrier phase observation value, the reconstructed carrier phase observation value, and the reconstructed pseudorange observation value are obtained respectively.

[0040] In embodiments of the present invention, the purpose of reconstruction is to recombine the observations of the separated upper and lower sidebands into equivalent observations corresponding to the main carrier and subcarrier of the broadband signal, so as to fully utilize its high accuracy and anti-multipath characteristics. Taking a modern broadband signal with AltBOC modulation as an example, AltBOC modulation can be regarded as modulating a pair of mutually orthogonal square wave complex subcarriers on a carrier (center frequency), thereby splitting the spectrum into upper and lower sidebands. Therefore, reconstruction in the observation domain is essentially to perform appropriate linear combination of the observations of the two sidebands to "invert" the observations corresponding to the carrier and subcarrier.

[0041] For example, since the goal of reconstructing pseudorange observations is to obtain a pseudorange corresponding to the entire GNSS broadband signal envelope, the arithmetic mean of the pseudorange observations of the upper and lower sideband signals can also be taken to obtain the reconstructed pseudorange observations.

[0042] For example, the upper and lower sideband phases can be linearly combined to obtain the reconstructed carrier phase observation value, so that the corresponding frequency is the center frequency of the GNSS broadband signal.

[0043] For example, the reconstructed subcarrier phase observation can be obtained by calculating the phase corresponding to the frequency difference between the upper and lower sideband phases.

[0044] In the signal processing stage, this invention independently tracks the upper and lower sideband signals using a tracking loop composed of a code loop and a carrier loop, generating pseudorange and carrier phase observations for the upper and lower sideband signals. In the observation generation stage, the subcarrier, carrier, and pseudorange observations of the broadband signal are reconstructed in the observation domain based on the pseudorange and carrier phase observations of the sidebands, releasing the accuracy potential of the broadband signal and providing high-quality observation data for GNSS standard point positioning. Furthermore, this scheme of independent sideband signal tracking and sideband observation reconstruction is compatible with traditional low-sampling-rate, narrow-bandwidth RF front-ends, and is expected to be widely applied in mass-market GNSS equipment and consumer terminals.

[0045] In S103 of this embodiment, the reliability of the reconstructed subcarrier phase observation is ensured through a quality control mechanism.

[0046] In some possible embodiments, quality control is performed on the reconstructed subcarrier phase observations based on the reconstructed subcarrier phase observations, the reconstructed carrier phase observations, and the reconstructed pseudorange observations, including: S103-1. Calculate the first difference between the reconstructed pseudorange observation and the reconstructed subcarrier phase observation at the current epoch, and the second difference between the reconstructed carrier phase observation and the reconstructed subcarrier phase observation. S103-2. Perform inter-epoch difference analysis on the first difference and the second difference respectively to form two subcarrier cycle slip test quantities; S103-3. Perform cycle slip detection on the reconstructed subcarrier phase observations based on the two subcarrier cycle slip test values, and estimate the integer cycle slip if a cycle slip is detected. Perform cycle slip repair on the reconstructed subcarrier phase observations based on the integer cycle slip.

[0047] Specifically, in S103-1, the reconstructed pseudorange observations at the current epoch k are calculated. and reconstructed subcarrier phase observations First difference and the reconstructed carrier phase observations and reconstructed subcarrier phase observations The second difference ,Right now:

[0048]

[0049] In S103-2, for the first difference Second difference Perform epoch-level differences separately to form two subcarrier cycle slip test quantities:

[0050] in, These are the cycle slip test values ​​for the two subcarriers, , and These are the reconstructed pseudorange observation, the reconstructed subcarrier phase observation, and the reconstructed carrier phase observation at the current epoch k, respectively. , and These are the reconstructed pseudorange observations, reconstructed subcarrier phase observations, and reconstructed carrier phase observations at epoch k-1, respectively.

[0051] In S103-3, if the cycle slip test value of any subcarrier calculated in S103-2 exceeds its corresponding preset test threshold, it is determined that a cycle slip has occurred in the reconstructed subcarrier observation value, and the integer cycle slip is estimated:

[0052] in, For integer cycle jumps, This is the subcarrier wavelength.

[0053] The integer cycle slips are compensated to the reconstructed subcarrier phase observations for cycle slip repair.

[0054] This invention introduces a quality control mechanism to perform cycle slip detection and cycle slip repair on the reconstructed subcarrier phase observations, thereby obtaining continuous cycle slip-free reconstructed subcarrier phase observations and ensuring the continuity and reliability of the reconstructed subcarrier phase observations.

[0055] In S104 of this embodiment, by estimating the floating-point ambiguity in the reconstructed subcarrier phase observation, the reconstructed subcarrier phase observation is converted into absolute distance information. Standard single-point positioning is then performed based on the absolute distance information, and receiver position information is output.

[0056] For example, by comparing the reconstructed pseudorange observations as a "coarse but unambiguous" distance reference with the "precise but ambiguous" distance measurement provided by the reconstructed subcarrier phase observations, the floating-point value of the ambiguity can be solved. Specifically, subtracting the observation equations of the reconstructed pseudorange observations from those of the reconstructed subcarrier phase observations eliminates common geometric distances and most common errors, leaving only the ambiguity-dominated component. By averaging this component over a time window, the floating-point ambiguity of the reconstructed subcarrier phase can be obtained.

[0057] Then, the floating-point ambiguity is converted into absolute distance information, a pseudorange observation equation is constructed, and the observation equation is solved by least squares to achieve GNSS standard single-point positioning.

[0058] Example 2 Please see Figure 2 , Figure 2 A second flowchart illustrating a GNSS standard point positioning method based on subcarrier observation reconstruction, provided as an embodiment of the present invention, includes: S201. Receive GNSS broadband signal intermediate frequency data, track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generate pseudorange observation values ​​and carrier phase observation values ​​of the upper sideband signal and lower sideband signal respectively. S202. Subtract the carrier phase observations of the upper sideband signal and the lower sideband signal, and then multiply by the subcarrier wavelength to obtain the subcarrier phase observations of the reconstructed GNSS broadband signal in the observation domain. S203. Add the carrier phase observations of the upper sideband signal and the lower sideband signal together, and then multiply them by the wavelength of the GNSS broadband signal to obtain the reconstructed carrier phase observations of the GNSS broadband signal in the observation domain. S204. The pseudorange observations of the upper sideband signal and the lower sideband signal are weighted by power to obtain the pseudorange observations of the GNSS broadband signal reconstruction in the observation domain. S205. Based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation, perform quality control on the reconstructed subcarrier phase observation. S206. Using the pseudorange satellite end hardware deviation correction number demodulated from the navigation message, correct the satellite end hardware deviation in the reconstructed pseudorange observation value to obtain the reconstructed pseudorange observation value correction value. S207. Calculate the third difference between the reconstructed pseudorange observation correction value and the reconstructed subcarrier phase observation value. Within a preset time window, take the average value of the third difference as the floating-point ambiguity of the reconstructed subcarrier phase observation value. S208. Based on the floating-point ambiguity, convert the reconstructed subcarrier phase observations into absolute distance information; S209. By combining satellite ephemeris and atmospheric delay models, the satellite orbital error, satellite clock error, ionospheric delay, and tropospheric delay in the absolute distance information are corrected, and the receiver position information is estimated.

[0059] This invention utilizes pseudorange observations and carrier phase observations of the upper and lower sideband signals to reconstruct carrier phase observations, subcarrier phase observations, and pseudorange observations of the GNSS broadband signal in the observation domain. This enables fast, reliable, and high-precision positioning, which is beneficial for improving the reliability of standard single-point positioning.

[0060] S201 in this embodiment can be referred to S101 in Embodiment 1, and will not be repeated here.

[0061] In S202 of this embodiment, the carrier phase observation values ​​of the upper sideband signal and the lower sideband signal in units of weeks are subtracted and then multiplied by the subcarrier wavelength to obtain the reconstructed subcarrier phase observation value in units of meters in the observation domain.

[0062] The formula for calculating the reconstructed subcarrier phase observation is as follows:

[0063] in, These are the reconstructed subcarrier phase observations at the current epoch k. For the subcarrier wavelength, These are the carrier phase observations for the upper and lower sideband signals, respectively.

[0064] In S203 of this embodiment, the carrier phase observation values ​​of the upper sideband signal and the lower sideband signal in units of weeks are added together and then multiplied by the wavelength of the GNSS broadband signal to obtain the reconstructed carrier phase observation value in units of meters in the observation domain.

[0065] The formula for calculating the reconstructed carrier phase observation is as follows:

[0066] in, These are the reconstructed carrier phase observations at the current epoch k. The wavelength of the GNSS broadband signal is the wavelength of its center carrier.

[0067] In S204 of this embodiment, the pseudorange observations of the upper sideband signal and the lower sideband signal are power-weighted to obtain the pseudorange observations of the GNSS broadband signal reconstruction in the observation domain.

[0068] For example, power weighting can be applied based on signal power. Assuming the upper and lower sideband signal powers are known, the formula for calculating the reconstructed pseudorange observations is:

[0069] in, These are the pseudorange observations for the upper sideband signal and the lower sideband signal, respectively. These are the weighting coefficients for the upper and lower sideband signals, respectively. For example, we can take... ,in, These are the carrier powers of the upper sideband signal and the lower sideband signal, respectively. For noise power spectral density, carrier-to-noise ratio , It can be used to measure signal quality.

[0070] S205 of this embodiment can be referred to 103 of Embodiment 1, and will not be repeated here.

[0071] In S206 of this embodiment, the pseudorange satellite-end hardware delay deviation correction number demodulated from the navigation message is used to correct the error in the reconstructed pseudorange observations. Specifically, the pseudorange satellite-end hardware delay deviation correction number is modulated in the broadcast ephemeris, which can be used to eliminate the influence of hardware delay caused by the satellite signal transmission link in the observations. If this is not eliminated, it will cause a systematic deviation in the receiver position. Any ground user only needs to correctly demodulate the navigation message to obtain this correction number to correct the deviation.

[0072] In S207 of this embodiment, the floating-point ambiguity of the reconstructed subcarrier phase observation is estimated based on the third difference between the reconstructed pseudorange observation correction value and the reconstructed subcarrier phase observation value.

[0073] In S208 of this embodiment, floating-point ambiguity is used to convert the reconstructed subcarrier phase observations into absolute distance information.

[0074] Specifically, the reconstructed subcarrier phase observations can be used to obtain absolute distance information after ambiguity removal. For example, by directly adding floating-point ambiguity to the reconstructed subcarrier phase observations, a reconstructed load wave phase observation converted into absolute distance information is obtained. This absolute distance information is characterized by continuity, high precision, and deambiguity.

[0075] In S209 of this embodiment, satellite orbit error, satellite clock error, ionospheric delay and tropospheric delay in absolute distance information are corrected by combining satellite ephemeris and atmospheric delay model to obtain corrected absolute distance information. Observation equations are then constructed, and the receiver position can be calculated using the corrected absolute distance information as the observation input and the optimal estimation method.

[0076] Understandably, the core principle of subcarrier-based positioning is essentially to use observations from four or more satellites to perform spatial rendezvous and calculate the receiver's position. Therefore, satellite ephemeris data can correct for satellite orbital errors and clock biases in the absolute range information, while atmospheric delay models can correct for ionospheric and tropospheric delays, resulting in corrected absolute range information. Using this corrected absolute range information as the observation input, and based on the relationship between this input and the receiver's position, an observation equation is constructed. Inputting the absolute range information into this equation allows the receiver's position to be calculated.

[0077] The satellite orbit is obtained by extrapolating the relative time difference between the signal transmission time and the ephemeris reference time using the Kepler orbital elements in the satellite ephemeris. The satellite clock error is obtained by extrapolating the clock error and clock drift parameters in the satellite ephemeris to obtain the satellite clock error value at the signal transmission time. The ionospheric delay can be obtained using the Kloubuchar model. The tropospheric delay can be obtained using the Saastamoinen model. The optimal estimation method can be weighted least squares, Kalman filtering, or factor graph optimization, etc.

[0078] This invention utilizes existing mature pseudorange bias products to design a method for correcting subcarrier observation bias and calculating floating-point ambiguity. It does not require upgrading the ground GNSS infrastructure to generate corresponding subcarrier bias products, thereby significantly reducing the difficulty of applying and promoting subcarrier positioning technology.

[0079] This invention, within the existing mainstream baseband tracking loop framework, fully leverages the high accuracy advantages of GNSS next-generation broadband signal subcarrier observations in noisy, multipath, and interference environments, thereby improving the single-point positioning performance of GNSS standards. This invention is applicable to mass-market GNSS devices and consumer terminals, effectively reducing the difficulty of large-scale application and promotion of subcarrier positioning technology, and has broad application prospects.

[0080] Example 3 Please see Figure 3 , Figure 3 A schematic diagram of a GNSS standard point positioning system based on subcarrier observation reconstruction, provided as an embodiment of the present invention, is shown. The system includes: The sideband observation generation module 310 is used to receive intermediate frequency data of GNSS broadband signal, track the upper sideband signal and lower sideband signal of GNSS broadband signal respectively, and generate pseudorange observations and carrier phase observations of the upper sideband signal and lower sideband signal respectively. The broadband observation reconstruction module 320 is used to reconstruct the subcarrier phase observation and carrier phase observation of the GNSS broadband signal in the observation domain based on the carrier phase observations of the upper sideband signal and the lower sideband signal, and to reconstruct the pseudorange observation of the GNSS broadband signal in the observation domain; and to perform quality control on the reconstructed subcarrier phase observation based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation. The subcarrier positioning module 330 includes a subcarrier floating-point ambiguity estimation submodule and a subcarrier standard point positioning submodule. The subcarrier floating-point ambiguity estimation submodule is used to estimate the floating-point ambiguity in the reconstructed subcarrier phase observations based on the reconstructed pseudorange observations. The subcarrier standard point positioning submodule is used to convert the reconstructed subcarrier phase observations into absolute distance information based on the floating-point ambiguity, perform standard point positioning based on the absolute distance information, and output the receiver position information.

[0081] The GNSS standard point positioning system based on subcarrier observation reconstruction described above and the GNSS standard point positioning method based on subcarrier observation reconstruction described above can be referred to in correspondence.

[0082] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4 As shown, the electronic device may include a processor 410, a communications interface 420, a memory 430, and a communication bus 440. The processor 410, communications interface 420, and memory 430 communicate with each other via the communication bus 440. The processor 410 can call logical instructions stored in the memory 430 to execute the GNSS standard point positioning method based on subcarrier observation reconstruction provided in the above-described method embodiments.

[0083] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, 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 a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0084] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the GNSS standard point positioning method based on subcarrier observation reconstruction provided in the above-described method embodiments.

[0085] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the GNSS standard point positioning method based on subcarrier observation reconstruction provided in the above-described method embodiments.

[0086] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0087] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A GNSS standard point positioning method based on subcarrier observation reconstruction, characterized in that, include: Receive intermediate frequency data of GNSS broadband signal, track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generate pseudorange observation values ​​and carrier phase observation values ​​of the upper sideband signal and lower sideband signal respectively; Based on the carrier phase observations of the upper sideband signal and the lower sideband signal, the subcarrier phase observations and carrier phase observations of the GNSS broadband signal are reconstructed in the observation domain, and the pseudorange observations of the GNSS broadband signal are also reconstructed in the observation domain. Based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation, the quality control of the reconstructed subcarrier phase observation is performed. Based on the reconstructed pseudorange observations, the floating-point ambiguity in the reconstructed subcarrier phase observations is estimated. Based on the floating-point ambiguity, the reconstructed subcarrier phase observations are converted into absolute distance information. Standard point positioning is performed based on the absolute distance information, and receiver position information is output.

2. The GNSS standard point positioning method based on subcarrier observation reconstruction according to claim 1, characterized in that, After receiving intermediate frequency data of the GNSS broadband signal, and tracking the upper sideband and lower sideband signals of the GNSS broadband signal respectively, and generating pseudorange observations and carrier phase observations of the upper sideband and lower sideband signals respectively, the method further includes: Cycle slip test parameters are constructed by interepoch difference to detect cycle slips in the carrier phase observations of the upper sideband signal and the lower sideband signal, respectively. In the case of receiving a single-frequency GNSS broadband signal, the first-order difference between epochs of the carrier phase observations of the upper sideband signal and the second-order difference between epochs based on the Doppler integral are calculated respectively to construct the cycle slip test quantity. For the case of receiving multi-frequency GNSS broadband signals, the first-order difference between epochs of the MW combination and the first-order difference between epochs of the GF combination are calculated for the observation values ​​of the upper sideband signal / lower sideband signal of two of the GNSS broadband signals, and the cycle slip test quantity is constructed. If a cycle slip is detected, a cycle slip marker is created.

3. The GNSS standard point positioning method based on subcarrier observation reconstruction according to claim 1, characterized in that, The step of reconstructing the subcarrier phase observations and carrier phase observations of the GNSS broadband signal in the observation domain based on the carrier phase observations of the upper sideband signal and the lower sideband signal includes: Subtract the carrier phase observations of the upper sideband signal and the lower sideband signal, and then multiply by the subcarrier wavelength to obtain the subcarrier phase observations of the reconstructed GNSS broadband signal in the observation domain. The carrier phase observations of the upper sideband signal and the lower sideband signal are added together and then multiplied by the wavelength of the GNSS broadband signal to obtain the reconstructed carrier phase observations of the GNSS broadband signal in the observation domain.

4. The GNSS standard point positioning method based on subcarrier observation reconstruction according to claim 3, characterized in that, The process of reconstructing the pseudorange observations of the GNSS broadband signal in the observation domain includes: The pseudorange observations of the upper sideband signal and the lower sideband signal are power-weighted to obtain the pseudorange observations reconstructed from the GNSS broadband signal in the observation domain.

5. The GNSS standard point positioning method based on subcarrier observation reconstruction according to claim 1, characterized in that, The quality control of the reconstructed subcarrier phase observations based on the reconstructed subcarrier phase observations, the reconstructed carrier phase observations, and the reconstructed pseudorange observations includes: Calculate the first difference between the reconstructed pseudorange observation and the reconstructed subcarrier phase observation at the current epoch, and the second difference between the reconstructed carrier phase observation and the reconstructed subcarrier phase observation. The first difference and the second difference are respectively subjected to epoch-time difference to form two subcarrier cycle slip test quantities; The reconstructed subcarrier phase observation is cycle-slip detected based on the two subcarrier cycle slip test values. If a cycle slip is detected, an integer cycle slip is estimated, and the reconstructed subcarrier phase observation is cycle-slip repaired based on the integer cycle slip.

6. The GNSS standard point positioning method based on subcarrier observation reconstruction according to claim 1, characterized in that, The step of estimating the floating-point ambiguity in the reconstructed subcarrier phase observations based on the reconstructed pseudorange observations includes: The satellite-end hardware bias correction value is corrected in the reconstructed pseudorange observation value by using the pseudorange hardware bias correction value demodulated from the navigation message. Calculate the correction value of the reconstructed pseudorange observation and the third difference between the reconstructed subcarrier phase observation; Within a preset time window, the average value of the third difference is taken as the floating-point ambiguity of the reconstructed subcarrier phase observation.

7. The GNSS standard point positioning method based on subcarrier observation reconstruction according to claim 6, characterized in that, The process of converting the reconstructed subcarrier phase observations into absolute distance information based on the floating-point ambiguity, performing standard point positioning based on the absolute distance information, and outputting receiver position information includes: The reconstructed subcarrier phase observations are added to the floating-point ambiguity to obtain the absolute distance information; By combining satellite ephemeris and atmospheric delay models, the satellite orbital error, satellite clock error, ionospheric delay, and tropospheric delay in the absolute distance information are corrected, and the receiver position information is estimated.

8. A GNSS standard point positioning system based on subcarrier observation reconstruction, characterized in that, include: The sideband observation generation module is used to receive intermediate frequency data of GNSS broadband signal, track the upper sideband signal and lower sideband signal of the GNSS broadband signal respectively, and generate pseudorange observations and carrier phase observations of the upper sideband signal and lower sideband signal respectively. The broadband observation reconstruction module is used to reconstruct the subcarrier phase observation and carrier phase observation of the GNSS broadband signal in the observation domain based on the carrier phase observations of the upper sideband signal and the lower sideband signal, and to reconstruct the pseudorange observation of the GNSS broadband signal in the observation domain; and to perform quality control on the reconstructed subcarrier phase observation based on the reconstructed subcarrier phase observation, the reconstructed carrier phase observation, and the reconstructed pseudorange observation. The subcarrier positioning module is used to estimate the floating-point ambiguity in the reconstructed subcarrier phase observations based on the reconstructed pseudorange observations, convert the reconstructed subcarrier phase observations into absolute distance information based on the floating-point ambiguity, perform standard single-point positioning based on the absolute distance information, and output receiver position information.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the GNSS standard single-point positioning method based on subcarrier observation reconstruction as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the GNSS standard single-point positioning method based on subcarrier observation reconstruction as described in any one of claims 1 to 7.

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