A method and system for low earth orbit satellite-borne GNSS receiver observation noise evaluation

Abstract

This invention discloses a method for evaluating the observation noise of a low-Earth orbit (LEO) spaceborne GNSS receiver, comprising: setting the observation data sampling interval T and the observation arc length h, and collecting observation data using the receiver under test (DUT); selecting a processing system isys from various GNSS systems based on the collected observation data; selecting a processing frequency ifreq based on the selected processing system isys; selecting a reference satellite rsat; sequentially processing all epoch observation data of each satellite in the processing system isys (excluding the reference satellite rsat), calculating the observation noise of the DUT to each satellite of the processing system isys at the processing frequency ifreq, and calculating the observation noise index of the DUT to the processing system isys at the processing frequency ifreq. Repeating the above steps yields the observation noise of the DUT to all frequencies of various GNSS systems. This invention achieves high-precision evaluation of the observation noise of a single receiver and is compatible with signals from various GNSS systems at various frequencies.

Description

Technical Field

[0001] This invention belongs to the field of satellite navigation and relates to a method and system for assessing observation noise of a low-Earth orbit spaceborne GNSS receiver. Background Technology

[0002] GNSS receiver observation noise, including pseudorange noise and carrier phase noise, is a core performance indicator of GNSS receivers. Currently, all low-Earth orbit (LEO) satellites acquire high-precision satellite coordinates and time information by carrying GNSS receivers. The performance of these onboard receivers directly impacts the application level of LEO satellites. At present, there is no unified method for assessing GNSS receiver observation noise, and existing methods each have their own advantages and disadvantages, making them unsuitable for evaluating the observation noise of LEO onboard GNSS receivers. Summary of the Invention

[0003] The technical problem solved by this invention is to provide a method and system for evaluating the observation noise of low-Earth orbit (LEO) spaceborne GNSS receivers, addressing the application requirements for noise assessment and resolving the problems existing in the prior art. This method achieves high-precision evaluation of the observation noise of a single receiver and is compatible with signals from various GNSS systems and frequencies. It is applicable not only to the evaluation of real GNSS satellite observation environments but also to the evaluation of GNSS signal simulation environments. Furthermore, this method can also solve the task of evaluating the observation noise of ground-based GNSS receivers.

[0004] The technical solution adopted in this invention is: a method for evaluating observation noise of a low-Earth orbit spaceborne GNSS receiver, comprising:

[0005] S1. Set the observation data sampling interval T and the observation arc length h, and use the receiver under test to collect the observation data;

[0006] S2. Based on the collected observation data, select the isys processing system from each GNSS system;

[0007] S3. Select the processing frequency ifreq based on the selected processing system isys;

[0008] S4. Select the reference satellite rsat; process all epoch observation data of each satellite in the processing system isys (excluding the reference satellite rsat) in sequence, and calculate the observation noise of the receiver under test for each satellite in the processing system isys at the processing frequency ifreq.

[0009] S5. Based on the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq. Calculate the observation noise performance of the receiver under test (RTD) to the processing system isys at the processing frequency ifreq.

[0010] S6. Repeat S3 to S5 to calculate the observation noise of the receiver under test for each frequency in the isys processing system.

[0011] S7. Repeat S2 to S6 to obtain the observation noise of the receiver under test for all frequencies of each GNSS system.

[0012] Furthermore, the observation data includes carrier phase observations and pseudorange observations, and the observation environment of the receiver under test is either observing real GNSS satellites or simulating an environment by connecting to GNSS signals.

[0013] Furthermore, in S2, the selectable processing systems include the BeiDou Navigation Satellite System, GPS system, GALILEO system, and GLONASS system.

[0014] Furthermore, in S4, all epochs of the collected observation data are traversed, and the number of observations corresponding to each GNSS satellite in the processing system isys by the receiver under test at the processing frequency ifreq is recorded, and the satellite with the most observations is taken as the reference satellite rsat.

[0015] Furthermore, the process sequentially processes all epoch observation data of each satellite in the isys system, excluding the reference satellite rsat, to calculate the observation noise of the receiver under test for each satellite in the isys system at the processing frequency ifreq. include:

[0016] S51. Select any satellite in the processing system isys other than the reference satellite rsat and denote it as the current processing satellite isat;

[0017] S52. Begin processing all epoch observation data of the currently processed satellite isat sequentially. Let i be the observation data of the processed satellite isat at the current processing epoch t. obs (t);

[0018] S53. In the observation data of the reference satellite rsat, find the observation data at time t, denoted as r. obs (t): If the observed data r is found obs (t) then calculates the inter-satellite single difference observation between the currently processed satellite isat and the reference satellite rsat. If not found, return to S52 to process the observation data for the next epoch;

[0019] In this context, α and β are both multiples.

[0020] S54. Repeat S52 and S53 to obtain the inter-satellite single-difference observation sequence for all epochs between the currently processed satellite isat and the reference satellite rsat:

[0021] S55. Calculate the observation noise of the receiver under test for the currently processed satellite ISAT at the processing frequency ifreq.

[0022] S56. Repeat S51 to S55 to obtain the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq.

[0023] Furthermore, the receiver under test (DUT) observes the current satellite ISAT at the processing frequency ifreq. for:

[0024]

[0025] Where n represents the inter-satellite single difference and fourth difference. The number of;

[0026] σ 2 This represents the observation noise amplification factor for the inter-satellite single-difference and fourth-order difference.

[0027] Furthermore, the inter-satellite single-difference fourth-order difference

[0028] Inter-satellite single difference and triple difference

[0029] Interstellar single difference and quadratic difference

[0030] Inter-satellite single difference and first difference

[0031] Furthermore, the observation noise amplification factor σ of the inter-satellite single-difference and fourth-order difference is... 2 Based on the inter-satellite single difference and fourth difference The expanded expression is calculated to obtain:

[0032] σ 2 =α×α+(-β)×(-β)+(-4α)×(-4α)+(4β)×(4β)+(6α)×(6α)+

[0033] (-6β)×(-6β)+(-4α)×(-4α)+(4β)×(4β)+α×α+(-β)×(-β),

[0034] Among them, inter-satellite single difference and fourth difference The expanded expression is as follows:

[0035]

[0036] Furthermore, the observation noise index of the receiver under test's processing system isys at the processing frequency ifreq is... The receiver under test (DSB) provides the observation noise of all satellites in the isys processing system at the processing frequency ifreq. Average value:

[0037]

[0038] Where, N sat The number of satellites involved in the calculation.

[0039] An evaluation system based on the above-described method for evaluating the observation noise of a low-Earth orbit spaceborne GNSS receiver includes:

[0040] The first module is used to set the observation data sampling interval T and the observation arc length h, receive the observation data collected by the receiver under test, select the processing system isys based on the collected observation data, and select the processing frequency ifreq based on the selected processing system isys.

[0041] The second module is used to select the reference satellite rsat and sequentially process all epoch observation data of each satellite in the isys processing system, excluding the reference satellite rsat, to calculate the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq.

[0042] The third module is used to determine the observation noise of each satellite in the isys processing system at the processing frequency ifreq based on the receiver under test. Calculate the observation noise performance of the receiver under test (RTD) to the processing system isys at the processing frequency ifreq.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] (1) This invention addresses the problem that receiver observation noise cannot be eliminated by multiple differences between epochs and that the high-order term residuals seriously affect the observation noise assessment. It proposes a method to eliminate the observation noise by first forming inter-satellite single differences in the observation noise assessment, which can completely eliminate the influence of receiver clock error on the observation noise assessment.

[0045] (2) The method of the present invention further eliminates the influence of higher-order terms such as distance variation and ionospheric error by performing a fourth difference on the inter-satellite single difference observations, thereby improving the accuracy and reliability of observation noise assessment.

[0046] (3) This invention proposes a method for calculating the amplification factor of observation noise, which avoids the problem of distortion or error in the calculation of observation noise caused by the amplification of observation noise;

[0047] (4) The method proposed in this invention has a clear theory, better evaluation accuracy, and wider applicability. It can evaluate the observation noise of a single GNSS receiver and is compatible with signals of various GNSS systems and frequencies. It is not only applicable to real GNSS satellite observation environments, but also to GNSS simulation environments. At the same time, this method can also be used for the observation noise evaluation of ground GNSS receivers. Attached Figure Description

[0048] Figure 1 This is a flowchart of the low-Earth orbit spaceborne GNSS receiver observation noise assessment method of the present invention;

[0049] Figure 2 The figure shows the evaluation results of the L1 and L2 frequency carrier phase noise of the G24 satellite by a low-Earth orbit satellite receiver, calculated using measured data and the method of the present invention.

[0050] Figure 3 The figure shows the evaluation results of the L1 and L2 frequency carrier phase noise of each satellite in the GPS system obtained by calculating the low-Earth orbit satellite-borne receiver using the method of the present invention with actual measurement data. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail with reference to the accompanying drawings.

[0052] The calculation process of the low-Earth orbit satellite-borne GNSS receiver observation noise assessment method disclosed in this invention is as follows: Figure 1 As shown, the first step is to eliminate the influence of receiver clock error on the assessment of observation noise by processing the inter-satellite single difference of the observation data. Then, the influence of higher-order terms of errors such as distance variation and ionosphere is further eliminated by performing four subtractions on the inter-satellite single difference, so as to achieve the purpose of high-precision assessment of receiver observation noise.

[0053] A method for assessing observation noise of a low-Earth orbit spaceborne GNSS receiver includes:

[0054] S1. The receiver under test collects observation data, including carrier phase observations and pseudorange observations. The observation environment is either a real GNSS satellite observation or a simulated environment by connecting to a GNSS signal. The sampling interval for the observation data is set to T, and the observation arc length is h (in hours).

[0055] S2. Select a processing system for the observation data collected in S1. The processing system that can be selected includes, but is not limited to, the BeiDou Navigation Satellite System (BDS), GPS system, GALILEO system, and GLONASS system. The selected processing system is denoted as isys.

[0056] S3. Based on S2, further select the processing frequency as ifreq. The selectable processing frequencies include, but are not limited to, BDS B1I / B2I / B3I / B1C / B2a, GPS L1 / L2 / L5, and GALILEO E1 / E5a / E5.

[0057] S4. Based on S3, traverse all epochs of the collected observation data, where the observation data is carrier phase observation value or pseudorange observation value, and record the number of observation values ​​of the receiver under test for each GNSS satellite corresponding to the ifreq frequency of the isys system.

[0058] S5. Take the satellite with the most GNSS satellite observations obtained from the receiver under test in S4 as the reference satellite, denoted as rsat;

[0059] S6. Except for the rsat satellite, start processing all satellites of the isys system in sequence, and denote the currently processed satellite as isat;

[0060] S7. Begin processing all epochs of ISAT satellite observation data sequentially. Let the current epoch be t, and the ISAT satellite observation data at the current epoch be denoted as i. obs (t);

[0061] S8. In the rsat satellite observation data, find the observation data at time t, denoted as r. obs If the observation data is found, proceed to the next step; otherwise, return to S7 to process the next epoch.

[0062] S9, transfer the isat satellite observation data at time t to i obs (t) α times and rsat satellite observation data r obs The difference between (t) and (β) is calculated to obtain the inter-satellite single-difference observation between the isat and rsat satellites, denoted as .

[0063] S10. Repeat S7 to S9 to obtain the inter-satellite single-difference observation sequence for all epochs of the ISAT and RSAT satellites, as follows:

[0064]

[0065] S11. Calculate the difference between consecutive epochs of the above inter-satellite single-difference observation sequence to obtain the first difference of the inter-satellite single difference, denoted as...

[0066]

[0067] S12, the first difference between the above inter-satellite single difference and the first difference. The difference between the preceding and following epochs is then calculated to obtain the interstellar single difference and quadratic difference.

[0068]

[0069] S13, the above inter-satellite single difference and quadratic difference The difference is then calculated between the preceding and following epochs to obtain the interstellar single difference and cubic difference.

[0070]

[0071] S14. For the above inter-satellite single difference and cubic difference... The difference is then calculated between the previous and next epochs to obtain the interstellar single difference and fourth difference.

[0072]

[0073] S15. Expanding the fourth difference expression for inter-satellite single difference yields:

[0074]

[0075] S16. Further, based on the above formula, the observation noise amplification factor of the inter-satellite single difference and fourth difference is calculated using the following formula:

[0076] σ 2 =α×α+(-β)×(-β)+(-4α)×(-4α)+(4β)×(4β)+(6α)×(6α)+

[0077] (-6β)×(-6β)+(-4α)×(-4α)+(4β)×(4β)+α×α+(-β)×(-β)

[0078] S17. Calculate the observation noise of the receiver under test for the ISAT satellite IFREQ frequency according to the following formula, where n represents the inter-satellite single-difference and fourth-difference. The number of;

[0079]

[0080] S18. Repeat S6 to S17 to obtain the observation noise of the receiver under test for each satellite at the ifreq frequency of the isys system.

[0081] S19. Calculate the observation noise of the receiver under test for all satellites at the ifreq frequency of the isys system, as obtained in S18. Calculate the average value to serve as the observed noise index of the isys system's ifreq frequency for the receiver under test. In the formula N sat The number of satellites involved in the calculation;

[0082]

[0083] S20. Repeat S3 to S19 to obtain the observed noise of the receiver under test for each frequency of the isys system.

[0084] S21. Repeat S2 to S20 to obtain the observation noise of the receiver under test for all frequencies of all GNSS systems.

[0085] The evaluation system based on the above-mentioned method for assessing observation noise of low-Earth orbit satellite-borne GNSS receivers includes:

[0086] The first module is used to set the observation data sampling interval T and the observation arc length h, receive the observation data collected by the receiver under test, select the processing system isys based on the collected observation data, and select the processing frequency ifreq based on the selected processing system isys.

[0087] The second module is used to select the reference satellite rsat and sequentially process all epoch observation data of each satellite in the isys processing system, excluding the reference satellite rsat, to calculate the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq.

[0088] The third module is used to determine the observation noise of each satellite in the isys processing system at the processing frequency ifreq based on the receiver under test. Calculate the observation noise index of the receiver under test to the processing system isys at the processing frequency ifreq.

[0089] In the second module, all epoch observation data of each satellite in the isys system, except for the reference satellite rsat, are processed sequentially to calculate the observation noise of the receiver under test for each satellite in the isys system at the processing frequency ifreq. The steps include the following:

[0090] S51. Select any satellite in the processing system isys other than the reference satellite rsat and denote it as the current processing satellite isat;

[0091] S52. Begin processing all epoch observation data of the currently processed satellite isat sequentially. Let i be the observation data of the processed satellite isat at the current processing epoch t. obs (t);

[0092] S53. In the observation data of the reference satellite rsat, find the observation data at time t, denoted as r. obs (t): If the observed data r is found obs (t) then calculates the inter-satellite single difference observation between the currently processed satellite isat and the reference satellite rsat. If not found, return to S52 to process the observation data for the next epoch;

[0093] In this context, α and β are both multiples.

[0094] S54. Repeat S52 and S53 to obtain the inter-satellite single-difference observation sequence for all epochs between the currently processed satellite isat and the reference satellite rsat:

[0095] S55. Calculate the observation noise of the receiver under test for the currently processed satellite ISAT at the processing frequency ifreq.

[0096] S56. Repeat S51 to S55 to obtain the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq.

[0097] Example:

[0098] A method for assessing observation noise of a low-Earth orbit (LEO) spaceborne GNSS receiver includes the following steps:

[0099] (1) Connect the receiver under test to the GNSS signal simulator for simulation observation. Set the observation data to include carrier phase observation value and pseudorange observation value. Set the observation data sampling interval to T = 1s and the observation arc length to h = 6 hours.

[0100] (2) For the observation data collected in the previous step, select a processing system. The processing systems that can be selected include, but are not limited to, BeiDou, GPS, GALILEO, and GLONASS. The selected processing system is denoted as isys; in this embodiment, isys = 'GPS' is selected.

[0101] (3) For the observation data collected in step (1), select the processing frequency ifreq. The selectable processing frequencies include, but are not limited to, BDS B1I / B2I / B3I / B1C / B2a, GPS L1 / L2 / L5, and GALILEOE1 / E5a / E5. In this embodiment, ifreq = 'L1' is selected.

[0102] (4) Traverse all epochs of the above observation data and count the number of carrier phase observations at the L1 frequency for each satellite of the GPS system.

[0103] (5) Take the satellite with the most carrier phase observations obtained in the previous step as the reference satellite, assuming it is satellite G02;

[0104] (6) Start traversing all GPS satellites except for reference satellite G02, assuming the currently processed satellite is G24;

[0105] (7) The carrier phase observation value y of all epochs L1 frequencies of the current satellite G24 is expressed as:

[0106] y = [y1, y2, y3, y4, y5, y6…]

[0107] (8) Among the carrier phase observations at L1 frequency for all epochs of reference satellite G02, the carrier phase observation value r at L1 frequency with the same observation time as satellite G24 is obtained by matching, and is expressed as:

[0108] r = [r1, r2, r3, r4, r5, r6…]

[0109] (9) The carrier phase observation values ​​of the current satellite G24 and the reference satellite G02 at the same observation time are subtracted according to the method proposed in the claim, and the preferred coefficients are selected as α=1, β=1, to obtain the inter-satellite single difference observation value. It is expressed as follows:

[0110]

[0111] (10) The time series of the above inter-satellite single difference observations are subtracted between consecutive epochs to obtain the time series of the first difference between the inter-satellite single difference. It is expressed as follows:

[0112]

[0113] (11) By subtracting the time series of the first difference between inter-satellite differences from each other in the above time series, we obtain the second difference between inter-satellite differences. It is expressed as follows:

[0114]

[0115] (12) By subtracting the time series of the above inter-satellite single difference quadratic difference between consecutive epochs, the inter-satellite single difference cubic difference time series is obtained. It is expressed as follows:

[0116]

[0117] (13) By subtracting the time series of the above inter-satellite single-difference triple difference from each subsequent epoch, we obtain the inter-satellite single-difference quadratic difference time series. It is expressed as follows:

[0118]

[0119] (14) The observation noise amplification factor of the inter-satellite single-difference fourth difference is calculated according to the method proposed in the claim:

[0120] σ 2 = 1×1+(-1)×(-1)+(-4)×(-4)+(4)×(4)+(6)×(6)+

[0121] (-6)×(-6)+(-4)×(-4)+(4)×(4)+1×1+(-1)×(-1)

[0122] =140

[0123] (15) The observation noise of the receiver under test for the L1 frequency of GPS G24 satellite is calculated according to the following formula:

[0124]

[0125] In the formula, n represents the inter-satellite single difference and fourth difference. The number of elements;

[0126] (16) Repeat steps (6) to (15) to obtain the observation noise of the receiver under test for each satellite of the GPS system L1 frequency, denoted as .

[0127] (17) The observation noise of the receiver under test for all satellites at the L1 frequency of the GPS system, calculated in step (16), is calculated. Calculate the average value to serve as the observation noise index of the receiver under test for the L1 frequency of the GPS system. In the formula N sat The number of satellites involved in the calculation;

[0128]

[0129] (18) Repeat steps (3) to (17), select the processing frequency as ifreq = 'L2', and obtain the observation noise of the receiver under test for the L2 frequency of the GPS system.

[0130] (19) Repeat steps (2) to (18), select isys='BDS' as the processing system, and obtain the observation noise of the receiver under test for all frequencies of GPS and BDS systems.

[0131] Figure 2 The observation noise of the low-Earth orbit satellite L1 and L2 frequencies of the GPS system G24 satellite, calculated using the method proposed in this invention based on measured data, is presented. The results show that the L1 carrier phase noise of the G24 satellite is 0.79 mm and the L2 carrier phase noise is 0.82 mm.

[0132] Figure 3 The observation noise of the low-Earth orbit satellite receiver at the L1 and L2 frequencies of each GPS satellite is given, calculated using the method proposed in this invention based on measured data. The results show that the L1 carrier phase noise of the GPS system is 0.94 mm and the L2 carrier phase noise is 1.01 mm.

[0133] The parts of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for assessing observation noise of a low-Earth orbit spaceborne GNSS receiver, characterized in that, include: S1. Set the sampling interval for observation data. and observed arc length The receiver under test is used to collect observation data; S2. Based on the collected observation data, select the isys processing system from each GNSS system; S3. Select the processing frequency ifreq based on the selected processing system isys; S4. Select the reference satellite rsat; process all epoch observation data of each satellite in the processing system isys (excluding the reference satellite rsat) in sequence, and calculate the observation noise of the receiver under test for each satellite in the processing system isys at the processing frequency ifreq. ; S5. Based on the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq. Calculate the observation noise index of the receiver under test to the processing system isys at the processing frequency ifreq. ; S6. Repeat S3~S5 to calculate the observation noise of the receiver under test for each frequency in the isys processing system. S7. Repeat S2~S6 to obtain the observation noise of the receiver under test for all frequencies of each GNSS system; The system sequentially processes all epoch observation data from each satellite in the isys system, excluding the reference satellite rsat, and calculates the observation noise of the receiver under test for each satellite in the isys system at the processing frequency ifreq. ,include: S51. Select any satellite in the processing system isys other than the reference satellite rsat and denote it as the current processing satellite isat; S52. Begin processing all epoch observation data of the currently processed satellite isat sequentially. Let the observation data of the processed satellite isat at the current processing epoch t be denoted as... ; S53. In the observation data of the reference satellite rsat, find the observation data at time t, and denote it as... If the observation data is found Then calculate the inter-satellite single-difference observations between the currently processed satellite isat and the reference satellite rsat. If not found, return to S52 to process the observation data for the next epoch; in, , All are multiples; S54. Repeat S52 and S53 to obtain the inter-satellite single-difference observation sequence for all epochs between the currently processed satellite isat and the reference satellite rsat: ; S55. Calculate the observation noise of the receiver under test for the currently processed satellite ISAT at the processing frequency ifreq. ; S56. Repeat S51~S55 to obtain the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq. ; The receiver under test observes the noise of the currently processed satellite ISAT at the processing frequency ifreq. for: ， Where n represents the inter-satellite single difference and fourth difference. The number of; This represents the observation noise amplification factor for the inter-satellite single-difference and fourth-order difference.

2. The method for assessing observation noise of a low-Earth orbit spaceborne GNSS receiver according to claim 1, characterized in that, The observation data includes carrier phase observations and pseudorange observations. The observation environment of the receiver under test is either observing real GNSS satellites or simulating an environment by connecting to GNSS signals.

3. The method for evaluating observation noise of a low-Earth orbit spaceborne GNSS receiver according to claim 1, characterized in that, In S2, the selectable processing systems include the BeiDou Navigation Satellite System, GPS system, GALILEO system, and GLONASS system.

4. The method for evaluating observation noise of a low-Earth orbit spaceborne GNSS receiver according to claim 1, characterized in that, In step S4, all epochs of the collected observation data are traversed, and the number of observations corresponding to each GNSS satellite in the processing system isys by the receiver under test at the processing frequency ifreq is recorded. The satellite with the most observations is then used as the reference satellite rsat.

5. The method for evaluating observation noise of a low-Earth orbit spaceborne GNSS receiver according to claim 1, characterized in that, The inter-satellite single difference and fourth difference ; Inter-satellite single difference and triple difference ; Interstellar single difference and quadratic difference ; Inter-satellite single difference and first difference .

6. The method for evaluating observation noise of a low-Earth orbit spaceborne GNSS receiver according to claim 5, characterized in that, The observation noise amplification factor of the inter-satellite single-difference and fourth-order difference. Based on the inter-satellite single difference and fourth difference The expanded expression is calculated to obtain: ， Among them, inter-satellite single difference and fourth difference The expanded expression is as follows: 。 7. The method for evaluating observation noise of a low-Earth orbit spaceborne GNSS receiver according to claim 1, characterized in that, The receiver under test observes the noise index of the processing system isys at the processing frequency ifreq. The observation noise of the receiver under test for all satellites in the isys processing system at the processing frequency ifreq. Average value: ； in, The number of satellites involved in the calculation.

8. An evaluation system for the low-Earth orbit spaceborne GNSS receiver observation noise assessment method according to any one of claims 1 to 7, characterized in that, include: The first module is used to set the sampling interval for observation data. and observed arc length It receives observation data collected by the receiver under test; selects the processing system isys based on the collected observation data; and selects the processing frequency ifreq based on the selected processing system isys. The second module is used to select the reference satellite rsat and sequentially process all epoch observation data of each satellite in the isys processing system, excluding the reference satellite rsat, to calculate the observation noise of the receiver under test for each satellite in the isys processing system at the processing frequency ifreq. ; The third module is used to determine the observation noise of each satellite in the isys processing system at the processing frequency ifreq based on the receiver under test. Calculate the observation noise index of the receiver under test to the processing system isys at the processing frequency ifreq. .

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