A performance evaluation method and related device for the impact of ionosphere on navigation

Abstract

The present application provides a performance evaluation method and related device for the impact of the ionosphere on navigation, and relates to the field of satellite navigation technology. First, dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments within the sampling period are obtained, and then the ionospheric delay of the satellite to be measured at each sampling moment is determined based on the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudo-range observations of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling moment; then, the ionospheric delay fluctuation value is determined based on the difference between the ionospheric delay amounts at two adjacent sampling moments, the ionospheric delay amount at the initial sampling moment, and the ionospheric delay amount at the current sampling moment; finally, when the ionospheric delay fluctuation value is greater than the first threshold value, it is determined that the ionosphere has an impact on navigation. The present application has the advantage of determining whether the ionosphere has an impact on navigation in a relatively short time.

Description

Technical Field

[0001] The present application relates to the field of satellite navigation technology, and in particular to a performance evaluation method and related device for the impact of the ionosphere on navigation. Background Art

[0002] Ionospheric scintillation refers to the rapid fluctuations in the amplitude, phase, polarization state and arrival angle of radio waves propagating through the irregular structure of ionospheric electron density, which causes the signal received by the receiver to rapidly fade. Ionospheric scintillation can cause the amplitude of the navigation signal reaching the ground to fade, the carrier phase to lose several whole cycles, and the carrier-to-noise ratio to drop suddenly, causing the receiver to increase the bit error rate and carrier phase measurement deviation when capturing and tracking, which in turn causes carrier phase cycle jumps and tracking loop loss, resulting in reduced user positioning accuracy and positioning success rate; in severe cases, it can affect the availability and integrity of the satellite navigation system.

[0003] In order to prevent ionospheric scintillation from affecting satellite navigation, it is necessary to perform a real-time performance evaluation of the ionosphere's impact on navigation during the navigation process. Once it is assessed that the ionosphere's impact on navigation is too large, ionospheric scintillation compensation needs to be performed, for example, using an ionosphere-related model to achieve compensation.

[0004] In the prior art, the performance evaluation of the impact of the ionosphere on navigation generally takes a long time to complete. Therefore, the ionosphere anomaly can often be evaluated only after the navigation has been affected by the ionosphere for a period of time, resulting in a lag in ionospheric flicker compensation.

[0005] In summary, in the prior art, the performance evaluation of the impact of the ionosphere on navigation has the problem of taking a long time. Summary of the invention

[0006] The purpose of the present application is to provide a performance evaluation method and related device for the impact of the ionosphere on navigation, so as to shorten the time required for the performance evaluation of the impact of the ionosphere on navigation.

[0007] In order to achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0008] In a first aspect, an embodiment of the present application provides a method for evaluating the performance of the ionosphere on navigation, the method comprising:

[0009] Acquire dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments in a sampling period, wherein the dual-frequency observation data includes carrier frequencies of L1 frequency point and L2 frequency point and pseudo-range observation values ​​of the satellite to be measured at L1 frequency point and L2 frequency point;

[0010] Determine the ionospheric delay of the satellite to be measured at each sampling time according to the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudorange observation values ​​of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling time;

[0011] Determine the ionospheric delay fluctuation value according to the difference between the ionospheric delays at two adjacent sampling moments, the ionospheric delay at the initial sampling moment, and the ionospheric delay at the current sampling moment;

[0012] When the ionospheric delay fluctuation value is greater than a first threshold, it is determined that the ionosphere affects navigation.

[0013] Optionally, the ionospheric delay fluctuation value satisfies the formula:

[0014]

[0015] Where B represents the fluctuation value of ionospheric delay, S i represents the ionospheric delay at the i-th sampling time, S i-1 represents the ionospheric delay at the i-1th sampling time, S n Indicates the ionospheric delay at the current sampling time, S 1 Represents the ionospheric delay at the initial sampling time.

[0016] Optionally, the ionospheric delay satisfies the formula:

[0017]

[0018] Where S represents the ionospheric delay, Indicates the carrier frequency of L1 frequency point, Indicates the carrier frequency of L2 frequency point, represents the pseudo-range observation value of the satellite to be measured at the L2 frequency point, It represents the pseudo-range observation value of the satellite to be measured at the L1 frequency point.

[0019] Optionally, after the step of determining the change in ionospheric delay, the method further includes:

[0020] When the ionospheric delay fluctuation value is less than the first threshold value and greater than the second threshold value, determining a change trend according to the ionospheric delay at each sampling moment;

[0021] When the change trend is an upward trend, obtaining the historical ionospheric delay amount corresponding to the current period in the historical data;

[0022] Determine the mean ionospheric delay value in the next sampling period according to the mean ionospheric delay value in the current sampling period and the historical ionospheric delay value;

[0023] When the average value of the ionospheric delay in the next sampling period is greater than a threshold, it is determined that the ionosphere affects the navigation.

[0024] Optionally, the step of determining the variation trend according to the ionospheric delay amount at each sampling moment includes:

[0025] The trend change value is determined based on the ionospheric delay at the current sampling moment, the exponential moving average at the previous sampling moment, and the set smoothing factor;

[0026] When the trend change value is greater than a set value, the change trend is determined to be an upward trend.

[0027] Optionally, the trend change value satisfies the formula:

[0028]

[0029] Among them, TC n Indicates the trend change value, S n Indicates the ionospheric delay at the current sampling time, EMA n Represents the exponential moving average at the current sampling time, EMA n-1 Represents the exponential moving average of the previous sampling moment, and EMA 1 The value of is equal to the ionospheric delay at the initial sampling time, and α represents the smoothing factor.

[0030] Optionally, the mean value of the ionospheric delay in the next sampling period satisfies the formula:

[0031]

[0032] in, represents the mean value of ionospheric delay in the next sampling period, Indicates the mean value of ionospheric delay in the current sampling period. Represents the average ionospheric delay of the previous sampling period in the historical data, represents the mean ionospheric delay of the next sampling period in the historical data, C 1 , C 2 , C 3 and C 4 They represent weights respectively, and C 1 +C 2 +C 3 +C 4 =1,C 1 >C 2 >C 3 >C 4 .

[0033] In a second aspect, an embodiment of the present application further provides a performance evaluation device for the impact of the ionosphere on navigation, the device comprising:

[0034] A data acquisition unit is used to acquire dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments in a sampling period, wherein the dual-frequency observation data includes carrier frequencies of L1 frequency point and L2 frequency point and pseudo-range observation values ​​of the satellite to be measured at L1 frequency point and L2 frequency point;

[0035] an ionospheric delay determination unit, configured to determine the ionospheric delay of the satellite to be measured at each sampling time according to the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudorange observations of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling time;

[0036] A delay fluctuation value determining unit, used to determine the ionospheric delay fluctuation value according to the difference between the ionospheric delays at two adjacent sampling moments, the ionospheric delay at the initial sampling moment, and the ionospheric delay at the current sampling moment;

[0037] The impact determination unit is used to determine that the ionosphere affects the navigation when the ionospheric delay fluctuation value is greater than a first threshold.

[0038] In a third aspect, an embodiment of the present application further provides a ground station, including:

[0039] A memory for storing one or more programs;

[0040] processor;

[0041] When the one or more programs are executed by the processor, the above-mentioned performance evaluation method of the impact of the ionosphere on navigation is implemented.

[0042] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for evaluating the performance of the impact of the ionosphere on navigation.

[0043] Compared with the prior art, this application has the following beneficial effects:

[0044] The present application provides a performance evaluation method and related device for the impact of the ionosphere on navigation. First, dual-frequency observation data of a satellite to be measured at multiple continuous sampling moments in a sampling period are obtained, and the dual-frequency observation data include carrier frequencies of L1 frequency points and L2 frequency points and pseudo-range observation values ​​of the satellite to be measured at L1 frequency points and L2 frequency points; then, the ionospheric delay of the satellite to be measured at each sampling moment is determined according to the carrier frequencies of L1 frequency points and L2 frequency points and the pseudo-range observation values ​​of L1 frequency points and L2 frequency points of the satellite to be measured at each sampling moment; then, the ionospheric delay fluctuation value is determined according to the difference between the ionospheric delay amounts at two adjacent sampling moments, the ionospheric delay amount at the initial sampling moment, and the ionospheric delay amount at the current sampling moment; finally, when the ionospheric delay fluctuation value is greater than a first threshold value, it is determined that the ionosphere has an impact on navigation. Since the present application does not need to use the ionospheric delay gradient to determine the impact on navigation, but instead uses the ionospheric delay fluctuation value to determine whether there is an impact on navigation, and the ionospheric delay fluctuation value can show large fluctuations in a short period of time, it is possible to determine whether the ionosphere has an impact on navigation in a shorter period of time.

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

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

[0047] Figure 1 A schematic diagram of a scenario for evaluating the performance of navigation impact in the prior art.

[0048] Figure 2 A schematic diagram of the modules of the ground station provided in an embodiment of the present application.

[0049] Figure 3 A partial exemplary flow chart of a method for evaluating the performance of the ionosphere's impact on navigation provided in an embodiment of the present application.

[0050] Figure 4 Another exemplary flowchart of a method for evaluating the performance of the ionosphere's impact on navigation provided in an embodiment of the present application.

[0051] Figure 5 A schematic diagram of a module of a device for evaluating the performance of the ionosphere's impact on navigation provided in an embodiment of the present application.

[0052] In the figure:

[0053] 100-ground station; 101-processor; 102-memory; 103-communication bus; 200-performance evaluation device of ionosphere impact on navigation; 210-data acquisition unit; 220-ionosphere delay determination unit; 230-delay fluctuation value determination unit; 240-impact determination unit. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0056] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0057] It should be noted that, in this document, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0058] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0059] As described in the background art, currently, when satellite navigation is used, ionospheric scintillation may affect navigation, so it is necessary to perform a performance evaluation on the impact of the ionosphere on navigation. However, the existing technology takes a long time to complete the evaluation.

[0060] For example, see Figure 1, which is a schematic diagram of a scenario for performance evaluation of navigation impact in the prior art. The satellite to be tested can send signals at the L1 frequency and the L2 frequency to the ground station. When the satellite to be tested is at time t1, the signal it sends will pass through the ionospheric gradient anomaly area and reach the ground station. The position where the signal passes through the anomaly area is puncture point 1, and the signal will be delayed when passing through the ionospheric gradient anomaly area. When the satellite to be tested is at time t2, the signal it sends will pass through the normal ionospheric area and reach the ground station. The position where the signal passes through the ionospheric gradient anomaly area is puncture point 2.

[0061] For the ground, it can receive the corresponding signal sent by the satellite at time t1 and determine the ionospheric delay at that time, recorded as A1; and it can also receive the corresponding signal sent by the satellite at time t2 and determine the ionospheric delay at that time, recorded as A2. Then the ground station can use the formula:

[0062] NI = (A2-A1) / D

[0063] The ionospheric delay gradient is determined, where NI represents the ionospheric delay gradient and D represents the geometric distance between puncture point 1 and puncture point 2. After the ionospheric delay gradient is determined, if the value of the ionospheric delay gradient is greater than the set value, it can be determined that the ionosphere has a greater impact on navigation at this time, and further data processing is required, such as compensation processing using an ionospheric model.

[0064] However, it can be seen from the above formula that in order to accurately determine the ionospheric delay gradient, the interval between time t1 and time t2 needs to be set slightly larger to ensure that the distance D can be more clearly identified. Generally speaking, it is necessary to set an appropriate time interval according to the actual situation. The time interval commonly used in the prior art is 5 minutes or more.

[0065] It can be seen that a long time is required when conducting the performance evaluation of the ionosphere's impact on navigation, resulting in the inability to effectively compensate for satellite data during the determination period.

[0066] In view of this, in order to solve the above problems, an embodiment of the present application provides a performance evaluation method for the impact of the ionosphere on navigation, which determines the impact of the ionosphere on navigation by utilizing the fluctuation value of the ionospheric delay amount, thereby achieving the effect of shortening the evaluation time.

[0067] It should be noted that the performance evaluation method of the ionosphere's impact on navigation provided in this application can be applied to ground stations, please refer to Figure 2 , Figure 2A schematic structural block diagram of a ground station provided in an embodiment of the present application is shown, and the ground station includes a memory 102, a processor 101, and a communication bus 103. The memory 102, the processor 101, and the communication bus 103 are electrically connected to each other directly or indirectly to achieve data transmission or interaction. For example, these elements can be electrically connected to each other through one or more communication buses or signal lines.

[0068] The memory 102 can be used to store software programs and modules, such as program instructions or modules corresponding to the performance evaluation device for the ionosphere on navigation provided in the embodiment of the present application. The processor 101 executes various functional applications and data processing by executing the software programs and modules stored in the memory 102, thereby executing the steps of the performance evaluation method for the ionosphere on navigation provided in the embodiment of the present application. The communication bus 103 can be used to communicate signaling or data with other node devices.

[0069] Among them, the memory 102 can be, but is not limited to, a random access memory (Random Access Memory, RAM), a read only memory (Read Only Memory, ROM), a programmable read-only memory (Programmable Read-Only Memory, PROM), an erasable programmable read-only memory (Erasable Programmable Read-Only Memory, EPROM), an electrically erasable programmable read-only memory (Electric Erasable Programmable Read-Only Memory, EEPROM), etc.

[0070] The processor 101 may be an integrated circuit chip with signal processing capability. The processor 101 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0071] Understandably, Figure 2 The structure shown is for illustration only. The ground station may also include Figure 2 More or fewer components as shown, or with Figure 2 Different configurations shown. Figure 2 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0072] The following uses a ground station as an illustrative execution entity to exemplify the performance evaluation method for the impact of the ionosphere on navigation provided in an embodiment of the present application.

[0073] See also Figure 3 , the performance evaluation method of the ionosphere impact on navigation provided in this application includes:

[0074] S102, obtaining dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments in a sampling period, wherein the dual-frequency observation data includes carrier frequencies of L1 frequency point and L2 frequency point and pseudo-range observation values ​​of the satellite to be measured at L1 frequency point and L2 frequency point.

[0075] S104, determining the ionospheric delay of the satellite to be measured at each sampling time according to the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudo-range observations of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling time.

[0076] S106, determining an ionospheric delay fluctuation value according to a difference between ionospheric delays at two adjacent sampling moments, the ionospheric delay at an initial sampling moment, and the ionospheric delay at a current sampling moment.

[0077] S108: When the ionospheric delay fluctuation value is greater than a first threshold, it is determined that the ionosphere affects the navigation.

[0078] Generally, in satellite navigation, the center frequency of the L1 frequency point is 1575.42 MHz, and the center frequency of the L2 frequency point is 1227.60 MHz. The satellite to be tested can send positioning data of two frequency points to the ground station at the same time.

[0079] The dual-frequency observation data of two frequency points are obtained at the ground station, and the data needs to be processed. Among them, the dual-frequency observation data includes observation data (dual-frequency pseudorange and carrier observation) and ephemeris data. In the data processing, it is necessary to first clean and filter, and only retain the data with both dual-frequency pseudorange and carrier. After that, the position of each satellite at each observation time, the azimuth and elevation angle relative to the receiver, and the puncture point coordinates are calculated according to the broadcast ephemeris in the satellite station relationship solution module, and the dual-frequency carrier observation is cycle-slip detected and repaired using the TurboEdit algorithm in the cycle-slip detection and repair module. In the carrier smoothing pseudorange module, the dual-frequency pseudorange observation is subjected to 100 s pseudorange smoothing filtering using the carrier observation without cycle slip. Then, in the ionospheric delay calculation module, the smoothed pseudorange observation is used to calculate the ionospheric delay.

[0080] Among them, the ionospheric delay satisfies the formula:

[0081]

[0082] Where S represents the ionospheric delay, Indicates the carrier frequency of L1 frequency point, Indicates the carrier frequency of L2 frequency point, represents the pseudo-range observation value of the satellite to be measured at the L2 frequency point, It represents the pseudo-range observation value of the satellite to be measured at the L1 frequency point.

[0083] It should be noted that when determining the ionospheric delay, calculations need to be performed for each sampling moment, and then the ionospheric delay fluctuation value can be determined based on the ionospheric delay at multiple sampling moments.

[0084] At present, the ionospheric delay gradient is generally used to monitor whether the ionosphere is abnormal. For example, when the ionospheric delay gradient is greater than 200mm / km, it indicates that the ionosphere is abnormal, which will affect navigation. However, the method of using the ionospheric delay gradient to monitor ionosphere anomalies generally takes a long time. The applicant's research found that when the ionosphere is abnormal, not only will the ionospheric delay gradient increase, but the ionospheric delay amount will also fluctuate greatly. Therefore, by calculating the fluctuation value of the ionospheric delay amount, it is possible to quickly determine whether the ionosphere is abnormal, thereby achieving a performance evaluation of the impact of the ionosphere on navigation.

[0085] Among them, when calculating the fluctuation value of the ionospheric delay, it can be implemented according to the period. Since the fluctuation can be reflected in a shorter time, the setting for the sampling period can be shorter. The general sampling period can be set to 1min~2min, and the sampling period provided in this application is 1min. Compared with the traditional method of calculating the ionospheric delay gradient for 5min, this application can more quickly determine the ionospheric anomaly, thereby ensuring that the satellite data can be effectively compensated more quickly.

[0086] Among them, in each sampling period, multiple sampling moments are set. For example, sampling is performed every 2 seconds, so there are 30 sampling moments in a sampling period of 1 minute. The ionospheric delay at each sampling moment can be used to determine the fluctuation value of the ionospheric delay in the current period. Once the fluctuation value is large, it means that the ionosphere is abnormal, and it can be determined that the ionosphere affects the navigation. At this time, the ground station can issue an instruction to prompt that the navigation data needs to be compensated. At the same time, an early warning indication can also be issued and sent to the aircraft.

[0087] As an implementation method, the ionospheric delay fluctuation value satisfies the formula:

[0088]

[0089] Where B represents the fluctuation value of ionospheric delay, S i represents the ionospheric delay at the i-th sampling time, S i-1 represents the ionospheric delay at the i-1th sampling time, S n Indicates the ionospheric delay at the current sampling time, S 1 Represents the ionospheric delay at the initial sampling time.

[0090] That is, when the ionospheric delay at the initial sampling time changes to the ionospheric delay at the current sampling time, the greater the fluctuation, the greater the corresponding ionospheric delay fluctuation value.

[0091] After determining the ionospheric delay fluctuation value, it is possible to determine whether the ionosphere is abnormal by comparing the ionosphere delay fluctuation value with the threshold. Since the sampling interval of each sampling period is short, when the determined ionosphere delay fluctuation value is large, it means that the ionosphere delay fluctuates violently in a short time, and at this time, there must be an ionosphere abnormality, so the ionosphere abnormality can be identified in a relatively short time.

[0092] Among them, the present application sets a first threshold and a second threshold, and the first threshold is greater than the second threshold. When the ionospheric delay fluctuation value is greater than the first threshold, it means that the ionospheric delay fluctuation is large, and it can be determined that the ionosphere affects the navigation; when the ionospheric delay fluctuation value is less than the first threshold, it means that the ionosphere delay fluctuation value is relatively small. In addition, the present application divides the ionospheric delay fluctuation value into three intervals, namely, the danger zone, the pending zone and the safe zone. When the ionospheric delay fluctuation value is greater than the first threshold, the ionospheric delay fluctuation value is in the danger zone. At this time, it is directly determined that the ionosphere affects the navigation, and a corresponding warning signal is generated. When the ionospheric delay fluctuation value is less than the first threshold and greater than the second threshold, the ionospheric delay fluctuation value is in the pending zone, and whether to issue a warning depends on the specific situation. When the ionospheric delay fluctuation value is less than the second threshold, the ionospheric delay fluctuation value is in the safe zone, and it is determined that the ionosphere will not affect the navigation at this time.

[0093] The applicant has found that when the ionospheric delay fluctuation value is in the pending zone and shows an upward trend, there is a possibility that the ionosphere will affect navigation in the future. On this basis, after step S106, refer to Figure 4 , the method further comprises:

[0094] S110, when the ionospheric delay fluctuation value is less than the first threshold value and greater than the second threshold value, determining a variation trend according to the ionospheric delay at each sampling moment.

[0095] S112: When the change trend is an upward trend, obtain the historical ionospheric delay amount corresponding to the current period in the historical data.

[0096] S114, determining the average ionospheric delay amount in the next sampling period according to the average ionospheric delay amount in the current sampling period and the historical ionospheric delay amount.

[0097] S116, when the average value of the ionospheric delay in the next sampling period is greater than the threshold, it is determined that the ionosphere affects the navigation.

[0098] In the present application, when it is determined that the ionospheric delay fluctuation value is less than the first threshold and greater than the second threshold, the ionospheric delay fluctuation value can be determined by statistics. As an implementation method, S110 includes:

[0099] S1101, determining a trend change value according to the ionospheric delay at the current sampling time, the exponential moving average at the previous sampling time, and a set smoothing factor;

[0100] S1102: When the trend change value is greater than the set value, determine that the change trend is an upward trend.

[0101] Among them, the trend change value satisfies the formula:

[0102]

[0103] Among them, TC n Indicates the trend change value, S n Indicates the ionospheric delay at the current sampling time, EMA n Represents the exponential moving average at the current sampling time, EMA n-1 Represents the exponential moving average of the previous sampling moment, and EMA 1 The value of is equal to the ionospheric delay at the initial sampling time, and α represents the smoothing factor.

[0104] In determining the trend change value TC n After that, the trend change value can be compared with the set value. Generally speaking, two set values ​​can be set, and the two set values ​​are positive and negative numbers. For example, one set value is Z and the other set value is -Z. When the trend change value is greater than Z, it means that the change trend is an upward trend; when the trend change value is less than Z and greater than -Z, it means that the change trend is a stable trend; when the trend change value is less than -Z, it means that the change trend is a downward trend.

[0105] When the trend of change is determined to be an upward trend, since the influence of the ionosphere is generally specific and periodic, for example, in a time period (the time period is usually related to the season), ionospheric anomalies may occur between 2 and 3 pm every day. Therefore, the historical ionospheric delay corresponding to the current period in the historical data can be obtained, and the average ionospheric delay in the next sampling period can be determined based on the average ionospheric delay in the current sampling period and the historical ionospheric delay, so that early warning can be made.

[0106] Among them, the mean value of the ionospheric delay in the next sampling period satisfies the formula:

[0107]

[0108] in, represents the mean value of ionospheric delay in the next sampling period, Indicates the mean value of ionospheric delay in the current sampling period. Represents the average ionospheric delay of the previous sampling period in the historical data, represents the mean ionospheric delay of the next sampling period in the historical data, C 1 , C 2 , C 3 and C 4 They represent weights respectively, and C 1 +C 2 +C 3 +C 4 =1,C 1 >C 2 >C 3 >C 4 .

[0109] It should be noted that when obtaining the historical ionospheric delay corresponding to the current cycle in the historical data, the average of the previous cycle and the next cycle is obtained. For example, if each cycle is 1 minute, then when the current sampling cycle is 14:02 (2:02 pm), the corresponding historical data obtained is the average of the ionospheric delay at 14:01 and 14:03 yesterday, and the average of the ionospheric delay at 14:01 and 14:03 yesterday and the average of the ionospheric delay at 14:01 and 14:02 today are used to predict the average of the ionospheric delay at 14:03 today. If the average of the ionospheric delay in the next sampling cycle is greater than the threshold, it can be determined that the ionosphere affects the navigation, thereby achieving the effect of early warning.

[0110] Of course, on the basis of the implementation scheme of the present application, the ionospheric gradient can also be combined to determine whether the ionosphere is abnormal, that is, on the basis of the above determination scheme, the formula NI = (A2-A1) / D is used to simultaneously determine the ionospheric delay gradient. If the ionospheric delay gradient is large, or the ionospheric delay amount fluctuation value is large, it can be determined that the ionosphere affects the navigation.

[0111] Based on the above implementation, the present application also provides a device 200 for evaluating the performance of the ionosphere on navigation. Figure 5 , the device comprises:

[0112] The data acquisition unit 210 is used to acquire dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments in the sampling period, and the dual-frequency observation data includes the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudo-range observation values ​​of the satellite to be measured at the L1 frequency point and the L2 frequency point.

[0113] It can be understood that the above S102 can be executed by the data acquisition unit 210 .

[0114] The ionospheric delay determination unit 220 is used to determine the ionospheric delay of the satellite to be measured at each sampling time according to the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudo-range observations of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling time.

[0115] It can be understood that the above S104 can be executed by the ionospheric delay amount determining unit 220.

[0116] The delay fluctuation value determining unit 230 is used to determine the ionospheric delay fluctuation value according to the difference between the ionospheric delays at two adjacent sampling moments, the ionospheric delay at the initial sampling moment, and the ionospheric delay at the current sampling moment.

[0117] It can be understood that the above S106 can be executed by the delay amount fluctuation value determining unit 230 .

[0118] The impact determination unit 240 is used to determine that the ionosphere affects the navigation when the ionospheric delay fluctuation value is greater than a first threshold.

[0119] It can be understood that the above S108 can be executed by the impact determination unit 240 .

[0120] In summary, the present application provides a performance evaluation method and related device for the impact of the ionosphere on navigation. First, dual-frequency observation data of a satellite to be measured at multiple continuous sampling moments within a sampling period are obtained, and the dual-frequency observation data include carrier frequencies of L1 frequency points and L2 frequency points and pseudo-range observation values ​​of the satellite to be measured at L1 frequency points and L2 frequency points; then, the ionospheric delay of the satellite to be measured at each sampling moment is determined according to the carrier frequencies of L1 frequency points and L2 frequency points and the pseudo-range observation values ​​of L1 frequency points and L2 frequency points of the satellite to be measured at each sampling moment; then, the ionospheric delay fluctuation value is determined according to the difference between the ionospheric delay amounts at two adjacent sampling moments, the ionospheric delay amount at the initial sampling moment, and the ionospheric delay amount at the current sampling moment; finally, when the ionospheric delay fluctuation value is greater than a first threshold value, it is determined that the ionosphere affects the navigation. Since the present application does not need to use the ionospheric delay gradient to determine the impact on navigation, but instead uses the ionospheric delay fluctuation value to determine whether there is an impact on navigation, and the ionospheric delay fluctuation value can show large fluctuations in a short period of time, it is possible to determine whether the ionosphere has an impact on navigation in a shorter period of time.

[0121] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0122] It will be apparent to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present application. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A performance evaluation method for the effect of the ionosphere on navigation, characterized in that: The method comprises: Acquire dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments in a sampling period, wherein the dual-frequency observation data includes carrier frequencies of L1 frequency point and L2 frequency point and pseudo-range observation values ​​of the satellite to be measured at L1 frequency point and L2 frequency point; Determine the ionospheric delay of the satellite to be measured at each sampling time according to the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudorange observation values ​​of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling time; Determine the ionospheric delay fluctuation value according to the difference between the ionospheric delays at two adjacent sampling moments, the ionospheric delay at the initial sampling moment, and the ionospheric delay at the current sampling moment; When the ionospheric delay fluctuation value is greater than a first threshold, it is determined that the ionosphere affects navigation; wherein, The ionospheric delay fluctuation value satisfies the formula: ； Where B represents the fluctuation value of ionospheric delay, S i represents the ionospheric delay at the i-th sampling time, S i-1 represents the ionospheric delay at the i-1th sampling time, S n It represents the ionospheric delay at the current sampling time, and S1 represents the ionospheric delay at the initial sampling time.

2. The method for evaluating the performance of the ionosphere on navigation according to claim 1, characterized in that: The ionospheric delay satisfies the formula: ； Where S represents the ionospheric delay, Indicates the carrier frequency of L1 frequency point, Indicates the carrier frequency of L2 frequency point, represents the pseudo-range observation value of the satellite to be measured at the L2 frequency point, It represents the pseudo-range observation value of the satellite to be measured at the L1 frequency point.

3. The method for evaluating the performance of the ionosphere's influence on navigation according to claim 1, characterized in that: After the step of determining the change in ionospheric delay, the method further comprises: When the ionospheric delay fluctuation value is less than the first threshold value and greater than the second threshold value, determining a change trend according to the ionospheric delay at each sampling moment; When the change trend is an upward trend, obtaining the historical ionospheric delay amount corresponding to the current period in the historical data; Determine the mean ionospheric delay value in the next sampling period according to the mean ionospheric delay value in the current sampling period and the historical ionospheric delay value; When the average value of the ionospheric delay in the next sampling period is greater than a threshold, it is determined that the ionosphere affects the navigation.

4. The performance evaluation method of the ionosphere effect on navigation according to claim 3, characterized in that: The steps of determining the variation trend according to the ionospheric delay at each sampling moment include: The trend change value is determined based on the ionospheric delay at the current sampling moment, the exponential moving average at the previous sampling moment, and the set smoothing factor; When the trend change value is greater than a set value, the change trend is determined to be an upward trend.

5. The method for evaluating the performance of the ionosphere's influence on navigation according to claim 4, characterized in that: The trend change value satisfies the formula: ； Among them, TC n Indicates the trend change value, S n Indicates the ionospheric delay at the current sampling time, EMA n Represents the exponential moving average at the current sampling time, EMA n-1 It represents the exponential moving average of the previous sampling time, and the value of EMA1 is equal to the ionospheric delay at the initial sampling time, and α represents the smoothing factor.

6. The method for evaluating the performance of the ionosphere's influence on navigation according to claim 3, characterized in that: The mean value of the ionospheric delay in the next sampling period satisfies the formula: ； in, represents the mean value of ionospheric delay in the next sampling period, Indicates the mean value of ionospheric delay in the current sampling period. Represents the average ionospheric delay of the previous sampling period in the historical data, It represents the mean ionospheric delay of the next sampling period in the historical data. C1, C2, C3 and C4 represent weights respectively, and C1+C2+C3+C4=1, C1>C2>C3>C4.

7. A performance evaluation device for the effect of the ionosphere on navigation, characterized in that: For executing the method according to any one of claims 1 to 6, the device comprises: A data acquisition unit is used to acquire dual-frequency observation data of the satellite to be measured at multiple continuous sampling moments in a sampling period, wherein the dual-frequency observation data includes carrier frequencies of L1 frequency point and L2 frequency point and pseudo-range observation values ​​of the satellite to be measured at L1 frequency point and L2 frequency point; an ionospheric delay determination unit, configured to determine the ionospheric delay of the satellite to be measured at each sampling time according to the carrier frequencies of the L1 frequency point and the L2 frequency point and the pseudorange observations of the L1 frequency point and the L2 frequency point of the satellite to be measured at each sampling time; A delay fluctuation value determining unit, used to determine the ionospheric delay fluctuation value according to the difference between the ionospheric delays at two adjacent sampling moments, the ionospheric delay at the initial sampling moment, and the ionospheric delay at the current sampling moment; The impact determination unit is used to determine that the ionosphere affects the navigation when the ionospheric delay fluctuation value is greater than a first threshold.

8. A ground station, characterized in that: include: A memory for storing one or more programs; processor; When the one or more programs are executed by the processor, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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