CN113253310B - Method and system for measuring group delay of high-precision GNSS receiver of carrier phase - Google Patents

Method and system for measuring group delay of high-precision GNSS receiver of carrier phase Download PDF

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CN113253310B
CN113253310B CN202110716497.7A CN202110716497A CN113253310B CN 113253310 B CN113253310 B CN 113253310B CN 202110716497 A CN202110716497 A CN 202110716497A CN 113253310 B CN113253310 B CN 113253310B
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group delay
carrier
phase
gnss receiver
measurement
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CN113253310A (en
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肖志斌
李蓬蓬
王峰毅
孙广富
芦艺
吴健
刘哲
黄龙
倪少杰
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National University of Defense Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/23—Testing, monitoring, correcting or calibrating of receiver elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position
    • G01S19/43—Determining position using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
    • G01S19/44—Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

The invention discloses a method and a system for measuring group delay of a high-precision GNSS receiver of a carrier phase. And then, by utilizing the characteristic that the group delay change in the narrow-band signal passband is smooth, the group delay is approximated to be a parabolic function, and the parabolic parameters and the integer ambiguity are traversed. And finally, when the difference value between the group delay characteristic obtained by traversing the parabolic parameters and the group delay characteristic obtained by combining the traversal integer ambiguity and the measured carrier phase is minimum, the group delay characteristic corresponding to the parabolic parameters can be considered as the actual group delay characteristic of the channel. Meanwhile, the group delay measurement of any frequency resolution can be realized by changing the frequency range of the frequency division multiple access signal.

Description

Method and system for measuring group delay of high-precision GNSS receiver of carrier phase
Technical Field
The invention relates to the technical field of satellite navigation, in particular to a method and a system for measuring group delay of a high-precision GNSS receiver of a carrier phase.
Background
GNSS receivers play an important role in GNSS systems, and receiver characteristics directly affect received signal quality and positioning results. The group delay characteristic has a large influence on the signal delay, and the accurate measurement of the group delay characteristic of the navigation channel plays an important role in simulating the navigation channel with high accuracy. If the measurement accuracy is increased, the resolution of group delay measurement is reduced, and the contradiction between the measurement accuracy and the resolution exists.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a method and a system for measuring group delay of a high-precision GNSS receiver of a carrier phase, which can solve the contradiction between measurement precision and resolution and ensure a high-precision measurement result.
The method for measuring the group delay of the high-precision GNSS receiver of the carrier phase comprises the following steps:
s100, generating a narrow-band spread spectrum signal, sending the narrow-band spread spectrum signal to a delay characteristic channel to be detected for capturing and tracking to obtain a code phase and carrier phase measured value, measuring time delay and corresponding integer ambiguity and traversal range according to the code phase, and traversing group delay measurement results according to the carrier phase and in combination with the integer ambiguity;
s200, approximating the group delay to a parabolic function, and traversing the group delay parabolic model parameters and the integer ambiguity in the narrow-band signal bandwidth;
s300, combining the traversal integer ambiguity and the measured carrier phase to obtain the group delay taucarrGroup delay obtained by subtracting ergodic parabolic parametersτObtaining group delay errorτ diff Taking the integer ambiguity corresponding to the minimum error value as the actual integer ambiguity corresponding to the carrier phase;
s400, obtaining group delay measurement values according to actual integer ambiguity, obtaining measurement errors of each measurement by taking the average value of reference group delay as a group delay measurement reference value, and obtaining each group of group delay measurement values after adjustment according to the measurement errors;
and S500, combining all the group delay measurement values to obtain the group delay measurement value with the specified resolution in the passband.
The system for measuring the group delay of the high-precision GNSS receiver of the carrier phase comprises a receiver, wherein the receiver is used for applying the method for measuring the group delay of the high-precision GNSS receiver of the carrier phase.
The method and the system for measuring the group delay of the high-precision GNSS receiver of the carrier phase at least have the following technical effects: the embodiment of the invention utilizes the characteristic of smooth change of group delay and the high group delay measurement precision of the carrier phase to carry out integer ambiguity estimation, thereby being capable of measuring the group delay characteristic with high precision, and measuring the channel group delay characteristic with high precision and any resolution by the carrier phase measurement value, and providing requirements for high-precision positioning middle-end test.
According to some embodiments of the present invention, the narrowband spread spectrum signal in step S100 adopts a signal mode of frequency division multiple access, and the number of generated signal groups is n, and the signal groups are divided into l frequency bands.
According to some embodiments of the present invention, the specific steps of generating the narrowband spread spectrum signal in step S100 are:
s101, generating an mth group of frequency division multiple access signals, wherein m =1,2, …, n;
s202, the frequency division multiple access signal is subjected to narrow-band filtering through a digital filter to obtain a narrow-band spread spectrum signal.
According to some embodiments of the present invention, the expression of the time delay measured according to the code phase in step S100 is:
Figure DEST_PATH_IMAGE002
,
wherein f iscodeIs the code rate of the pseudo code,
Figure DEST_PATH_IMAGE004
the code phase of the ith narrowband spread spectrum signal; its corresponding integer ambiguity N0Is expressed as
Figure DEST_PATH_IMAGE006
Wherein f iscarrIs the carrier frequency.
According to some embodiments of the invention, the group delay τ in step S300carrIs calculated as
Figure DEST_PATH_IMAGE008
Wherein N is the integer ambiguity,
Figure DEST_PATH_IMAGE010
carrier phase, f, measured for the ith narrowband spread spectrum signalcarrIs the carrier frequency.
According to some embodiments of the present invention, the formula of the group delay τ in step S300 is:
Figure DEST_PATH_IMAGE012
wherein i represents the number of pass bands, f represents the frequency within the group delay pass band, ai，biIs the group delay parabola parameter in the ith pass band, ai，biIn ns.
According to some embodiments of the present invention, the traversal range in the step S200 is (-10 to 10) ns, and the traversal step size is 0.1.
According to some embodiments of the invention, the group delay measurement in step S400 is
Figure DEST_PATH_IMAGE014
，
Where m represents the number of groups of the current signal and N (i) is the integer ambiguity corresponding to the minimum error value.
According to some embodiments of the present invention, the measurement error of each measurement in step S400 is formulated as
Figure DEST_PATH_IMAGE016
，
Wherein tau isc(m) is the measured reference group delay, m represents the number of groups of the current signal.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a flowchart of a group delay measurement method of a high-precision GNSS receiver of a carrier phase according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
Referring to fig. 1, a method for measuring group delay of a high-precision GNSS receiver with carrier phase includes the following steps:
assume a given group delay measurement resolution of 0.1 MHz. First, a narrowband spread spectrum signal is generated, and the bandwidth of the narrowband signal is 0.5 MHz. In order to ensure the consistency of signal generation time, a signal mode of frequency division multiple access is adopted, so that the number of generated signal groups is 5. The mth group of frequency division multiple access signals is generated as Sm(f) The frequency range is 0-10 MHz, the frequency is divided into 20 frequency bands, the center frequency is (-0.6+0.1m +0.5i) MHz, i =1,2, …,20, and m =1,2, …, 5. Simultaneously selecting the center frequency of the time delay of the reference group as fc=20 MHz. The digital filter is used for carrying out narrow-band filtering, and the frequency domain expression form of the obtained narrow-band spread spectrum signal is as follows:
Figure DEST_PATH_IMAGE018
Hi(f) is the ith bandpass filter. For the mth set of FDMA signals, when i<At 21, the pass band range is (0.1m +0.5 i-0.85-01m +0.5i-0.35) MHz. When i =21, the pass band range is (19.75-20.25) MHz. Sending the ith narrow-band spread spectrum signal to a receiver for capturing and tracking to measure the code phase
Figure DEST_PATH_IMAGE019
The delay can be measured from the code phase as:
Figure 679191DEST_PATH_IMAGE002
wherein f iscodeIs the pseudo code rate. Its corresponding integer ambiguity N0Obtained from the formula
Figure 193349DEST_PATH_IMAGE006
Wherein f iscarrIs the carrier frequency. The traversal range of the whole-cycle ambiguity can be considered as
Figure DEST_PATH_IMAGE021
。
Simultaneously measuring the carrier phase
Figure DEST_PATH_IMAGE022
And if the measured carrier phase is in one carrier period, and the integer ambiguity is N, the time delay can be measured according to the carrier phase as follows:
Figure 650875DEST_PATH_IMAGE008
wherein N has a value range of
Figure DEST_PATH_IMAGE023
。
Then, the group delay in the ith pass band is approximated to a parabolic model according to the center frequency and the bandwidth of the narrowband spread spectrum signal as follows:
Figure 275367DEST_PATH_IMAGE012
wherein f represents the frequency in the group delay passband, ai，biIs the parameter of the group delay parabola model in the ith pass band, and the unit is ns. To ai，biAnd traversing, wherein the traversal range is (-10) ns, and the traversal step length is 0.1, so that 40000 parabolic models can be obtained by each segment of group delay.
The resulting group delay error τdiffCan be obtained by the following formula:
Figure DEST_PATH_IMAGE025
since the integer ambiguity of the group delay measured by the carrier phase is also obtained by traversal, 440000 group delay errors are finally obtained. The integer ambiguity n (i) corresponding to the minimum error value can be regarded as the actual integer ambiguity corresponding to the ith carrier phase. The mth group delay measurement is:
Figure DEST_PATH_IMAGE027
simultaneously measuring the reference group delay of
Figure DEST_PATH_IMAGE029
. Taking the average value of the reference group delay as the group delay measurement reference value, the measurement error of each measurement can be obtained as follows:
Figure DEST_PATH_IMAGE031
the group delay measurement of the mth set of FDMA signals is
Figure DEST_PATH_IMAGE033
. All the group delay measurement values are combined, and the group delay measurement value with the specified resolution in the passband can be obtained.
The invention also comprises a group delay measuring system of the high-precision GNSS receiver of the carrier phase, which comprises the receiver applying the method.
In summary, in the embodiments of the present invention, a narrowband spread spectrum signal is first generated, and the narrowband spread spectrum signal passes through a channel with a delay characteristic of a group to be measured, and is captured and tracked to obtain measured values of a code phase and a carrier phase. Because the delay measurement accuracy according to the code phase is not high and the noise interference is greater than the integer ambiguity of the carrier phase, the delay measurement value calculated according to the code phase can only provide an approximate range for the integer ambiguity of the carrier phase. And then, by utilizing the characteristic that the group delay change in the narrow-band signal passband is smooth, the group delay is approximated to be a parabolic function, and the parabolic parameters and the integer ambiguity are traversed. And finally, when the difference value between the group delay characteristic obtained by traversing the parabolic parameters and the group delay characteristic obtained by combining the traversal integer ambiguity and the measured carrier phase is minimum, the group delay characteristic corresponding to the parabolic parameters can be considered as the actual group delay characteristic of the channel. Meanwhile, the group delay measurement of any frequency resolution can be realized by changing the frequency range of the frequency division multiple access signal.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.

Claims (10)

1. A group delay measurement method of a high-precision GNSS receiver of a carrier phase is characterized by comprising the following steps:
s100, generating a narrow-band spread spectrum signal, sending the narrow-band spread spectrum signal to a delay characteristic channel to be detected for capturing and tracking to obtain a code phase and carrier phase measured value, measuring time delay and corresponding integer ambiguity and traversal range according to the code phase, and traversing group delay measurement results according to the carrier phase and in combination with the integer ambiguity;
s200, approximating the group delay to a parabolic function, and traversing the group delay parabolic model parameters and the integer ambiguity in the narrow-band signal bandwidth;
s300, combining the traversal integer ambiguity and the measured carrier phase to obtain the group delay taucarrGroup delay obtained by subtracting ergodic parabolic parametersτObtaining group delay errorτ diff Taking the integer ambiguity corresponding to the minimum error value as the actual integer ambiguity corresponding to the carrier phase;
s400, obtaining a group delay measurement value according to actual integer ambiguity, sending a narrowband spread spectrum signal to a receiver for capturing and tracking to obtain reference group delay, taking the average value of the reference group delay as a group delay measurement reference value to obtain a measurement error of each measurement, and obtaining each group delay measurement value after adjustment according to the measurement error;
and S500, combining all the group delay measurement values to obtain the group delay measurement value with the specified resolution in the passband.
2. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: in step S100, the narrowband spread spectrum signal adopts a frequency division multiple access signal mode, and the number of generated signal groups is n, and the signal groups are divided into l frequency bands.
3. The method of claim 2, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the specific steps of generating the narrowband spread spectrum signal in step S100 are:
s101, generating an mth group of frequency division multiple access signals, wherein m =1,2, …, n;
s202, the frequency division multiple access signal is subjected to narrow-band filtering through a digital filter to obtain a narrow-band spread spectrum signal.
4. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the expression of the time delay measured according to the code phase in step S100 is:
Figure 668571DEST_PATH_IMAGE001
，
wherein f iscodeIs the code rate of the pseudo code,
Figure 897558DEST_PATH_IMAGE002
the code phase of the ith narrowband spread spectrum signal; its corresponding integer ambiguity N0Is expressed as
Figure 899012DEST_PATH_IMAGE003
Wherein f iscarrIs the carrier frequency.
5. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the group delay τ in step S300carrIs calculated as
Figure 629071DEST_PATH_IMAGE004
Wherein N is the integer ambiguity,
Figure 219321DEST_PATH_IMAGE005
carrier phase, f, measured for the ith narrowband spread spectrum signalcarrIs the carrier frequency.
6. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the formula of the group delay τ in step S300 is:
Figure 743843DEST_PATH_IMAGE006
wherein i represents the number of pass bands, f represents the frequency within the group delay pass band, ai，biIs the group delay parabola parameter in the ith pass band, ai，biIn ns.
7. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the traversal range in the step S200 is (-10) ns, and the traversal step length is 0.1.
8. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the group delay measurement value in step S400 is
Figure 232593DEST_PATH_IMAGE007
，
Where m represents the number of groups of the current signal, N (i) is the integer ambiguity corresponding to the minimum error value,
Figure 376130DEST_PATH_IMAGE008
carrier phase, f, measured for the ith narrowband spread spectrum signalcarrIs the carrier frequency.
9. The method of claim 1, wherein the method for measuring group delay of the carrier-phase GNSS receiver comprises: the formula of the measurement error of each measurement in step S400 is
Figure 696253DEST_PATH_IMAGE009
，
Wherein tau isc(m) is the measured reference group delay, m represents the number of groups of the current signal.
10. A carrier-phase high-precision GNSS receiver group delay measurement system comprising a receiver for applying the carrier-phase high-precision GNSS receiver group delay measurement method of any of claims 1 to 9.
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