A satellite navigation positioning receiver and a method for improving positioning accuracy of the receiver

Abstract

The application discloses a satellite navigation positioning receiver and a method for improving positioning accuracy of the satellite navigation positioning receiver, and improves the positioning accuracy of the satellite navigation positioning receiver. The method comprises the following steps: a reference satellite is determined in advance by the receiver; after frame synchronization is completed, signals of all satellites are sampled, and sampling values are counted; a propagation time difference between other satellites and the reference satellite is calculated according to the counted sampling values; and the signal propagation time of each satellite is calculated based on the signal propagation time of the reference satellite. According to the method and the receiver, the signal propagation time of each satellite is more accurate, the pseudo-range value calculated from the signal propagation time is more accurate, and the satellite navigation positioning accuracy is improved.

Description

Technical Field

[0001] This invention relates to satellite navigation and positioning technology, and more particularly to a satellite navigation and positioning receiver and a method for improving the positioning accuracy of the satellite navigation and positioning receiver. Background Technology

[0002] Global Navigation Satellite Systems (GNSS) are widely used in various fields. Currently, there are four main global navigation and positioning systems: the United States' Global Positioning System (GPS), China's BeiDou Navigation Satellite System (Compass or BeiDou, abbreviated as BD), Russia's Global Navigation Satellite System (GLONASS), and the European Union's Galileo system, the largest civilian satellite navigation and positioning system. Among them, GPS is the most mature, BD and GLONASS have made phased progress, while the Galileo system is still in its early stages.

[0003] With the rapid development of satellite navigation technology and applications, single-satellite positioning system receivers can no longer meet user needs in order to improve the accuracy, availability, continuity, and integrity of navigation and positioning. Receiver manufacturers have gradually shifted towards multi-mode system receivers, meaning receivers that simultaneously support multiple navigation systems. Currently, dual-mode and tri-mode navigation receivers exist. With improvements in manufacturing processes and the development and refinement of navigation systems, it is foreseeable that more navigation systems will be integrated into satellite navigation receivers in the future.

[0004] The basic idea of ​​navigation and positioning calculation is to calculate the receiver's position based on basic satellite information and GNSS receiver observations. Receiver positioning accuracy is one of the most critical performance indicators for the receiver and of greatest concern to users. There are many methods to improve receiver positioning accuracy; preprocessing the observations is a relatively computationally intensive and easily implemented method, thus attracting considerable research attention. In satellite navigation and positioning, the GNSS receiver's observations mainly consist of pseudorange and Doppler frequency shift. In positioning, pseudorange is used as the observation, and its expression is:

[0005] ρ=LightSpeed*TravelTime (1)

[0006] Wherein, LightSpeed ​​is the speed of light, which is a constant in satellite navigation systems, i.e., LightSpeed ​​= 299792458 m / s; TravelTime is the signal propagation time, which is the time required from the satellite signal being transmitted to the receiver receiving the signal. The accuracy of the signal propagation time directly determines the accuracy of the observed pseudorange value.

[0007] Currently, the most commonly used solution methods are least squares localization (LSQ) and Kalman filter localization (KF), and their localization equations and observation equations are the same.

[0008]

[0009] Where (x,y,z) are the satellite's position coordinates; (X,Y,Z) are the preset values ​​for the receiver's position coordinates; δt (u) ρ represents the receiver clock offset in meters; ρ is the measured pseudorange. Equation (2) shows that the accuracy of the pseudorange measurement directly affects the navigation and positioning accuracy. Equation (1) shows that a 1ms deviation in the satellite signal propagation time will result in a nearly 300km deviation in the pseudorange, an error that is unacceptable in navigation and positioning. Therefore, to improve the accuracy of satellite navigation and positioning, it is necessary to improve the accuracy of the satellite signal propagation time calculation.

[0010] Currently, the propagation time of satellite signals is mainly calculated from the satellite signal transmission time and the receiver signal reception time, i.e.

[0011] TravelTime = t (u) -t (s) (3)

[0012] Among them, t (u) t represents the signal reception time of the receiver. (s) This refers to the satellite's signal transmission time.

[0013] t (s) This is the system time for the navigation system. After the signal completes bit synchronization and frame synchronization, the signal transmission time can be accurately calculated.

[0014] t (u) The receiver time, obtained directly from the receiver, is the local time. Firstly, there is an inherent error between the receiver time and UTC time. Secondly, the conversion between UTC and navigation system time also introduces some error. Therefore, the calculated signal propagation time will introduce significant errors into the calculation of observations. Furthermore, the calculated signal propagation time cannot be directly used to determine whether the signal propagation time of each satellite is correct. Figure 1 This is the current process for calculating observations. Summary of the Invention

[0015] To address the aforementioned technical problems, this invention provides a satellite navigation and positioning receiver, as well as a method for improving the positioning accuracy of the satellite navigation and positioning receiver, thereby enhancing the positioning accuracy of the satellite navigation receiver.

[0016] To achieve the objective of this invention, a method for improving the positioning accuracy of a satellite navigation and positioning receiver is provided, the method comprising:

[0017] The receiver predetermines a reference satellite. After completing frame synchronization, it samples the signals of all satellites and counts the sampled values. Based on the counted sampled values, it calculates the propagation time difference between other satellites and the reference satellite. Using the signal propagation time of the reference satellite as a reference, it calculates the signal propagation time of each other satellite.

[0018] Furthermore, the receiver is a multi-mode receiver, used to receive observations from at least the first navigation system and the second navigation system respectively; the sampling and statistical analysis of the signals from all satellites includes: the receiver using the counter of the first analog-to-digital converter in the first navigation system to sample and count the signals from all satellites in the second navigation system, and statistically analyzing the sampled values; and using the counter of the second analog-to-digital converter in the second navigation system to sample and count the signals from all satellites in the first navigation system, and statistically analyzing the sampled values.

[0019] Further, the statistical sampling value includes: counting the number of sampling points from the current positioning point to one or more subframes preceding the subframe where the current positioning point is located, to obtain the sampling value; or, counting the number of sampling points from the current positioning point to the starting edge of the previous subframe of the subframe where the current positioning point is located, to obtain the sampling value.

[0020] Furthermore, the step of calculating the propagation time difference between other satellites and the reference satellite based on the statistically obtained sampled values ​​includes: using the sampled values ​​of the reference satellite as a benchmark, calculating the difference between the sampled values ​​of other satellites and the sampled values ​​of the reference satellite, and converting the difference into the propagation time difference.

[0021] Furthermore, the method further includes: when calculating the propagation time difference between other satellites and the reference satellite, referring to the uncertainty of the propagation time difference, wherein the uncertainty of the propagation time difference is determined by the sampling frequency of the signal.

[0022] Furthermore, the method also includes, after obtaining the propagation time difference between other satellites and the reference satellite, determining whether the propagation time difference exceeds the time difference limit range; if it does, then removing the satellite.

[0023] Furthermore, the step of calculating the signal propagation time of each other satellite based on the signal propagation time of the reference satellite includes: calculating the signal propagation time of the reference satellite, and calculating the signal propagation time of each other satellite based on the propagation time difference between each other satellite and the reference satellite.

[0024] Furthermore, the reference satellite is the satellite with the best signal quality.

[0025] To achieve the objectives of this invention, the present invention also provides a satellite navigation and positioning receiver, the receiver comprising a sampling module and a calculation module, wherein:

[0026] The sampling module is used to pre-determine a reference satellite, and after frame synchronization is completed, sample the signals of all satellites and count the sampled values.

[0027] The calculation module is used to calculate the propagation time difference between other satellites and the reference satellite based on the sampling values ​​statistically obtained by the sampling module, and to calculate the signal propagation time of each other satellite based on the signal propagation time of the reference satellite.

[0028] Furthermore, the receiver is a multi-mode receiver, used to receive observations from at least the first navigation system and the second navigation system respectively; the sampling module includes a first sampling unit and a second sampling unit, wherein the first sampling unit is a counter of the first analog-to-digital converter in the first navigation system, used to sample and count all satellite signals in the second navigation system and count the sampled values; the second sampling unit is a counter of the second analog-to-digital converter in the second navigation system, used to sample and count all satellite signals in the first navigation system and count the sampled values.

[0029] Furthermore, the sampling module counts the sampled values ​​in the following ways: it counts the number of sampling points from the current positioning point to one or more subframes preceding the subframe where the current positioning point is located, and obtains the sampled values; or it counts the number of sampling points from the current positioning point to the starting edge of the previous subframe where the current positioning point is located, and obtains the sampled values.

[0030] Furthermore, the calculation module calculates the propagation time difference between other satellites and the reference satellite based on the statistically obtained sampled values, including: the calculation module uses the sampled values ​​of the reference satellite as a benchmark to calculate the difference between the sampled values ​​of other satellites and the sampled values ​​of the reference satellite, and converts the difference into the propagation time difference.

[0031] Furthermore, the calculation module is also used to: when calculating the propagation time difference between other satellites and the reference satellite, refer to the uncertainty of the propagation time difference, wherein the uncertainty of the propagation time difference is determined by the sampling frequency of the signal.

[0032] Furthermore, the calculation module is also used to: after obtaining the propagation time difference between other satellites and the reference satellite, determine whether the propagation time difference exceeds the time difference limit range; if it does, then remove the satellite.

[0033] Furthermore, the calculation module calculates the signal propagation time of each other satellite based on the signal propagation time of the reference satellite, including: the calculation module calculates the signal propagation time of the reference satellite, and calculates the signal propagation time of each other satellite based on the propagation time difference between each other satellite and the reference satellite.

[0034] To achieve the objectives of this invention, the present invention also provides a satellite navigation and positioning receiver, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the program to implement the steps in the above-described method.

[0035] Using the method and receiver of this invention, the signal propagation time of other satellites is obtained based on the signal propagation time of a reference satellite. The signal propagation time of the reference satellite is relatively accurate among visible satellites. Therefore, the accuracy of the signal propagation time of the satellite being sought depends more on the accuracy between sampling points. As can be seen from the empirical value of the time interval between sampling points, its value is more accurate. Thus, the signal propagation time value of each satellite is more accurate, and the pseudorange value calculated from the signal propagation time is more accurate, thereby improving the accuracy of satellite navigation and positioning.

[0036] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0037] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0038] Figure 1 This is the existing conventional pseudorange calculation process;

[0039] Figure 2 This is a flowchart of a method for improving the positioning accuracy of a satellite navigation and positioning receiver according to Embodiment 1 of the present invention;

[0040] Figure 3 This is a flowchart of the pseudorange calculation method according to Embodiment 2 of the present invention;

[0041] Figure 4This is a schematic diagram of a satellite navigation and positioning receiver according to Embodiment 4 of the present invention;

[0042] Figure 5 This is a schematic diagram of another structure of the satellite navigation and positioning receiver according to Embodiment 4 of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0044] The steps illustrated in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases the steps shown or described may be performed in a different order than that presented here.

[0045] Example 1

[0046] This embodiment provides a method for improving the positioning accuracy of a satellite navigation and positioning receiver, such as... Figure 2 As shown, including S21-S22:

[0047] S21. The receiver pre-determines a reference satellite, and after completing frame synchronization, samples the signals of all satellites and counts the sampled values.

[0048] S22. Calculate the propagation time difference between other satellites and the reference satellite based on the statistical sampling values, and calculate the signal propagation time of each other satellite using the signal propagation time of the reference satellite as the benchmark.

[0049] By adopting the above method, the error introduced by using receiver time to calculate satellite signal propagation time in the prior art is avoided, which can improve the measurement accuracy of satellite navigation and positioning receiver observations, and thus improve the positioning accuracy of the receiver.

[0050] In an optional embodiment, the receiver is a multi-mode receiver, used to receive observations from at least the first navigation system and the second navigation system respectively; in step S22 above, sampling the signals of all satellites and counting the sampled values ​​includes: the receiver using the counter of the first analog-to-digital converter in the first navigation system to sample and count all satellite signals in the second navigation system and counting the sampled values; and using the counter of the second analog-to-digital converter in the second navigation system to sample and count all satellite signals in the first navigation system and counting the sampled values.

[0051] Since different navigation satellite systems typically use different signal frequencies, their signal sampling frequencies also differ, requiring each system to have an independent digital-to-analog converter (ADC). To fully utilize the capabilities of the ADC, different systems within a multi-mode receiver can use each other's ADCs to calculate satellite signal propagation time. This improves the accuracy of measured values ​​and allows for the elimination of unsatisfactory observations based on temporal consistency.

[0052] The statistical sampling values ​​described in the above method can be obtained in one of the following ways:

[0053] Count the number of sampling points from the current location point to one or more subframes preceding the current location point, and obtain the sampled value;

[0054] The number of sampling points from the current location point to the starting edge of the previous subframe of the subframe containing the current location point is counted to obtain the sampled value.

[0055] In an optional embodiment, step S22 above, which involves calculating the propagation time difference between other satellites and the reference satellite based on the statistically obtained sampled values, includes: using the sampled values ​​of the reference satellite as a benchmark, calculating the difference between the sampled values ​​of other satellites and the sampled values ​​of the reference satellite, and converting the difference into a propagation time difference.

[0056] Optionally, the above method further includes: when calculating the propagation time difference between other satellites and the reference satellite, the uncertainty of the propagation time difference is determined by the sampling frequency of the signal.

[0057] Optionally, the above method further includes, after obtaining the propagation time difference between other satellites and the reference satellite, determining whether the propagation time difference exceeds the time difference limit; if it does, then removing the satellite.

[0058] In an optional embodiment, step S22 above, which involves calculating the signal propagation time of each other satellite based on the signal propagation time of the reference satellite, includes: calculating the signal propagation time of the reference satellite, and calculating the signal propagation time of each other satellite based on the propagation time difference between each other satellite and the reference satellite.

[0059] In principle, any satellite can be used as a reference satellite. However, to improve the reliability of the observations, the satellite with the highest quality signal is selected as the reference satellite. There are many ways to determine the reference satellite, which will not be listed here.

[0060] In this embodiment of the invention, the signal propagation time of other satellites is obtained based on the signal propagation time of a reference satellite. The signal propagation time of the reference satellite is relatively accurate among visible satellites. Therefore, the accuracy of the signal propagation time of the satellite being calculated depends more on the accuracy between sampling points. Empirical values ​​of the time intervals between sampling points show that these values ​​are more precise, thus making the signal propagation time value of each satellite more accurate. The pseudorange value calculated from the signal propagation time is more accurate, thereby improving the accuracy of satellite navigation and positioning.

[0061] Example 2

[0062] This embodiment provides a detailed description of the methods described in the above embodiments. For example... Figure 3 As shown, it includes the following steps:

[0063] Step S31: The receiver locks onto the signal;

[0064] Step S32: Determine if frame synchronization is successful. If yes, proceed to step S33; otherwise, return to step S31.

[0065] Step S33: Determine the subframe number;

[0066] The GNSS systems, through adjustments made by the ground monitoring unit, ensure that the time difference between each satellite's clock and the system's time remains within 1µs, thus ensuring that each satellite begins transmitting its subframe start edge at approximately the same time. However, due to varying distances between the receiver and the satellites, as well as delays such as ionospheric and tropospheric delays, the receiver receives the subframe start edge at slightly different times. In fact, the signal start edge from the satellite closer to the receiver arrives first, followed by the signal start edge from the satellite farther away. After frame synchronization is completed, the subframe number and start edge position of each subframe in the signal can be determined.

[0067] Step S34: Sampling count, statistical analysis of sampled values;

[0068] An N-bit counter can be added to the ADC of each system in the multi-mode receiver; N can be, for example, 32. In this embodiment, the number of sampling points from the positioning point of each satellite to the start edge of the previous subframe is counted each time, N. i Let be the number of sampling points for the i-th satellite. The counter is reset to zero and starts counting again when the positioning point enters the next subframe. Each statistical count takes place over time T0. This ensures that all sampling points are counted without making the counter too large. Alternatively, it can count the number of sampling points from the current positioning point to one or more subframes preceding the current positioning point.

[0069] Step S35: Calculate the propagation time difference between the satellite and the reference satellite;

[0070] A reference satellite is pre-selected, its observational information is obtained, the signal propagation time of the reference satellite is calculated, and the propagation time difference between the current satellite and the reference satellite is calculated based on the signal propagation time of the reference satellite.

[0071] In principle, any satellite visible to the receiver can be used as a reference satellite. To ensure reliability, the satellite with the best signal quality is selected as the reference satellite. There are various principles for selecting a reference satellite, such as carrier-to-noise ratio (CN0), which will not be listed here. After determining the reference satellite, its signal propagation time (TravelTime) is calculated using current methods, in milliseconds, and the number of sampling points in its channel is N0.

[0072] The difference in signal propagation time between each satellite and the reference satellite is ΔT i In this embodiment, the uncertainty of the time difference is considered when calculating the propagation time difference between the satellite and the reference satellite signals, making the calculation results more accurate. The unit of time difference is milliseconds.

[0073]

[0074] Where i≠0, ΔT i The uncertainty is F s The sampling frequency of the signal.

[0075] From equation (4), we can see that ΔT i The accuracy and uncertainty are mainly determined by the signal sampling frequency F. s The decision is based on the intermediate frequency and the Nyquist theorem, which states that F... s It is on the order of MHz, or on the order of 10e-7S.

[0076] Step S36: Determine whether the time difference between the current satellite and the reference satellite signal propagation is less than the system's time difference limit. If it is less, proceed to step S37. If it is not less, remove the current satellite and return to step 31.

[0077] Each system has its own time difference limit of ±ΔT0, for example, ΔT0 = 19ms for GPS, but this generally varies between different systems. If ΔT i If the time difference exceeds the limit, the observation does not meet the time consistency condition between observations, so it should be removed before solving.

[0078] Step S37, calculate the satellite signal propagation time:

[0079] TravelTime(i)=ΔT i +floor(TravelTime) (5)

[0080] Here, floor() refers to floor. According to equation (5), the accuracy of the signal propagation time TravelTime(i) mainly depends on ΔT. i As analyzed above, the accuracy of the signal propagation time value is greatly improved. According to equation (1), the receiver's observed pseudorange value is more accurate, which also improves the receiver's positioning accuracy.

[0081] Example 3

[0082] This embodiment provides a detailed description of the methods described in the above embodiments. Taking a dual-mode system receiver composed of GPS and BDS as an example, this embodiment uses BDS as an auxiliary system to calculate the signal propagation time of GPS satellites, ultimately completing the pseudorange calculation. It should be noted that the method in this embodiment is not limited to dual-mode system receivers but can also be applied to multi-mode receivers. Furthermore, in the actual operation of a multi-mode receiver, there is no primary / secondary distinction between the systems; rather, they assist each other.

[0083] According to statistics, the shortest distance between a GPS satellite and a receiver on the Earth's surface is 20,192 km, and the longest distance is 25,785 km. According to equation (1), the propagation time of a GPS satellite signal is 67 ms to 86 ms, meaning that the time difference between signals emitted at the same time and reaching the receiver on the Earth's surface does not exceed 19 ms, i.e., ΔT0 = 19.

[0084] Once the receiver tracking loop locks onto the GPS signal and performs frame synchronization, the subframe number and its start edge can be determined. Using the start edge of the previous subframe of the current positioning point as the starting point, the ADC counter in the BDS is used to count the number of sampling points from the positioning point of each GPS satellite to the start edge of the previous subframe of the current positioning point. N i Let be the number of sampling points for the i-th satellite. Because the distance between the receiver and each satellite varies, the arrival time of the same starting edge from different satellites at the receiver differs, resulting in different numbers of sampling points for different satellites.

[0085] Here, the carrier-to-noise ratio (CN0) is used as the standard for selecting a reference satellite. Within the specified range, a higher CN0 indicates higher signal quality. The signal propagation time (TravelTime) of the reference satellite is calculated using the original method. Although there are errors, it is the most accurate among visible satellites. The number of sampling points for the reference satellite is N0.

[0086] Let the sampling frequency of the signal be F. S Given that the C / A code rate is 1.023e6Hz, statistical analysis shows that the maximum Doppler shift of the C / A code is 6.32Hz. SIn addition to satisfying Nyquist's theorem, the value of F must also be a non-integer multiple of (1.023e6+6.32) Hz. S Empirical values ​​could be 16.368MHz, 20.0MHz, 26.0MHz, etc. In this embodiment, considering downsampling, a decimation ratio of 4 is chosen; in other embodiments, the decimation ratio could also be 5 or 6. The time interval between two adjacent sampling points is then T0, in seconds.

[0087] T0 = ​​4 / F S (6)

[0088] The empirical values ​​for T0 are 2.44793e-7s, 2.0e-7s, and 1.53846e-7s. Calculate the propagation time deviation ΔT between the signal from each visible satellite and the reference satellite. i The unit is milliseconds:

[0089] ΔT i =((N) i -N0)*T0)±T0)*1000 (7)

[0090] Where, N i Let N be the number of sampling points for the i-th satellite, and N0 be the number of sampling points for the reference channel. ±T0 represents ΔT. i The uncertainty. If the signal propagation time deviation |ΔT| between the satellite and the reference satellite is calculated. i If |>ΔT0, then the satellite observation has a problem and is not suitable for use in positioning calculation.

[0091] Calculate the signal propagation time of the i-th satellite, where i ≠ 0

[0092] TravelTime(i)=ΔT i +floor(TravelTime) (8)

[0093] The signal propagation time value of the reference satellite is relatively accurate among visible satellites. It has been rounded down to make the accuracy of the signal propagation time of the satellite being calculated depend more on the accuracy between sampling points. Based on the empirical value of T0, its value is more accurate, resulting in a more precise signal propagation time value for each satellite. As shown in equation (1), the calculated pseudorange value is more accurate, thereby improving the accuracy of satellite navigation and positioning.

[0094] Example 4

[0095] This embodiment provides a satellite navigation and positioning receiver, and the methods described in the above embodiments are also applicable to this embodiment. Figure 4 As shown, the receiver includes a sampling module 41 and a calculation module 42, wherein:

[0096] The sampling module 41 is used to pre-determine a reference satellite, and after frame synchronization is completed, sample the signals of all satellites and count the sampled values.

[0097] The calculation module 42 is used to calculate the propagation time difference between other satellites and the reference satellite based on the sampled values ​​collected by the sampling module 41, and to calculate the signal propagation time of each other satellite based on the signal propagation time of the reference satellite.

[0098] In one optional embodiment, the receiver is a multi-mode receiver, used to receive observations from at least the first navigation system and the second navigation system respectively; the sampling module 41 includes a first sampling unit and a second sampling unit, wherein the first sampling unit is a counter of the first analog-to-digital converter in the first navigation system, used to sample and count all satellite signals in the second navigation system and count the sampled values; the second sampling unit is a counter of the second analog-to-digital converter in the second navigation system, used to sample and count all satellite signals in the first navigation system and count the sampled values.

[0099] The sampling module 41 uses one of the following methods to collect sampled values:

[0100] Count the number of sampling points from the current location point to one or more subframes preceding the current location point, and obtain the sampled value;

[0101] The number of sampling points from the current location point to the starting edge of the previous subframe of the subframe containing the current location point is counted to obtain the sampled value.

[0102] In an optional embodiment, the calculation module 42 calculates the propagation time difference between other satellites and the reference satellite based on the statistically sampled values, including: the calculation module 42 calculates the difference between the sampled values ​​of other satellites and the sampled values ​​of the reference satellite based on the sampled values ​​of the reference satellite, and converts the difference into a propagation time difference.

[0103] In an optional embodiment, the calculation module 42 is further configured to: when calculating the propagation time difference between other satellites and the reference satellite, the uncertainty of the propagation time difference is determined by the sampling frequency of the signal.

[0104] In an optional embodiment, the calculation module 42 is further configured to: after obtaining the propagation time difference between other satellites and the reference satellite, determine whether the propagation time difference exceeds the time difference limit; if it does, then remove the satellite.

[0105] In an optional embodiment, the calculation module 42 calculates the signal propagation time of each other satellite based on the signal propagation time of the reference satellite, including: the calculation module 42 calculates the signal propagation time of the reference satellite, and calculates the signal propagation time of each other satellite based on the propagation time difference between each other satellite and the reference satellite.

[0106] The aforementioned satellite navigation and positioning receiver can be a computer device, which can be, for example... Figure 5 The structure shown includes a processor 51, a memory 52, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it can implement some or all of the steps in Embodiment 1 or Embodiment 2.

[0107] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical units; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0108] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for improving the positioning accuracy of a satellite navigation and positioning receiver, characterized in that, The method includes: The receiver predetermines a reference satellite. After completing frame synchronization, it samples the signals of all satellites and counts the sampled values. Based on the counted sampled values, it calculates the propagation time difference between other satellites and the reference satellite. Using the signal propagation time of the reference satellite as a reference, it calculates the signal propagation time of each other satellite. The step of calculating the propagation time difference between other satellites and the reference satellite based on the statistically obtained sampled values ​​includes: using the sampled values ​​of the reference satellite as a benchmark, calculating the difference between the sampled values ​​of other satellites and the sampled values ​​of the reference satellite, and converting the difference into the propagation time difference.

2. The method according to claim 1, characterized in that, The receiver is a multimode receiver, used to receive observations from at least the first navigation system and the second navigation system respectively; The sampling and statistical analysis of signals from all satellites includes: the receiver using the counter of the first analog-to-digital converter in the first navigation system to sample and count the signals from all satellites in the second navigation system, and statistical analysis of the sampled values. The counter of the second analog-to-digital converter in the second navigation system is used to sample and count all satellite signals in the first navigation system, and the sampled values ​​are statistically analyzed.

3. The method according to claim 1 or 2, characterized in that, The statistical sample values ​​include: Count the number of sampling points from the current location point to one or more subframes preceding the current location point to obtain the sampled value; or The number of sampling points from the current location point to the starting edge of the previous subframe of the subframe containing the current location point is counted to obtain the sampled value.

4. The method according to claim 1, characterized in that, The method further includes: when calculating the propagation time difference between other satellites and the reference satellite, referring to the uncertainty of the propagation time difference, wherein the uncertainty of the propagation time difference is determined by the sampling frequency of the signal.

5. The method according to claim 1 or 4, characterized in that, The method further includes, after obtaining the propagation time difference between other satellites and the reference satellite, determining whether the propagation time difference exceeds the time difference limit range; if it does, then removing the satellite.

6. The method according to claim 1, characterized in that, The calculation of the signal propagation time of each other satellite based on the signal propagation time of the reference satellite includes: The signal propagation time of the reference satellite is calculated, and the signal propagation time of each other satellite is calculated based on the propagation time difference between each other satellite and the reference satellite.

7. The method according to claim 1, characterized in that, The reference satellite is the one with the best signal quality.

8. A satellite navigation and positioning receiver, characterized in that, The receiver includes a sampling module and a calculation module, wherein: The sampling module is used to pre-determine a reference satellite, and after frame synchronization is completed, sample the signals of all satellites and count the sampled values. The calculation module is used to calculate the propagation time difference between other satellites and the reference satellite based on the sampling values ​​statistically obtained by the sampling module, and to calculate the signal propagation time of each other satellite based on the signal propagation time of the reference satellite. The calculation module calculates the propagation time difference between other satellites and the reference satellite based on the statistically sampled values, including: the calculation module uses the sampled values ​​of the reference satellite as a reference to calculate the difference between the sampled values ​​of other satellites and the sampled values ​​of the reference satellite, and converts the difference into the propagation time difference.

9. The receiver according to claim 8, characterized in that, The receiver is a multimode receiver, used to receive observations from at least the first navigation system and the second navigation system respectively; The sampling module includes a first sampling unit and a second sampling unit. The first sampling unit is a counter of the first analog-to-digital converter in the first navigation system, used to sample and count all satellite signals in the second navigation system and count the sampled values. The second sampling unit is a counter of the second analog-to-digital converter in the second navigation system, used to sample and count all satellite signals in the first navigation system and count the sampled values.

10. The receiver according to claim 8 or 9, characterized in that, The sampling module counts the sampled values ​​in the following ways: it counts the number of sampling points from the current location point to one or more subframes preceding the subframe where the current location point is located, and obtains the sampled values; or it counts the number of sampling points from the current location point to the starting edge of the previous subframe where the current location point is located, and obtains the sampled values.

11. The receiver according to claim 8, characterized in that, The calculation module is also used to: when calculating the propagation time difference between other satellites and the reference satellite, refer to the uncertainty of the propagation time difference, wherein the uncertainty of the propagation time difference is determined by the sampling frequency of the signal.

12. The receiver according to claim 8 or 11, characterized in that, The calculation module is also used to: after obtaining the propagation time difference between other satellites and the reference satellite, determine whether the propagation time difference exceeds the time difference limit range; if it does, then remove the satellite.

13. The receiver according to claim 8, characterized in that, The calculation module calculates the signal propagation time of each other satellite based on the signal propagation time of the reference satellite, including: The calculation module calculates the signal propagation time of the reference satellite, and calculates the signal propagation time of each other satellite based on the propagation time difference between each other satellite and the reference satellite.

14. A satellite navigation and positioning receiver, 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 steps of the method as described in any one of claims 1-7.

Images