A method, apparatus, and storage medium for estimating the carrier-to-noise ratio of digital navigation signals.

Abstract

A method, apparatus, and storage medium for estimating the carrier-to-noise ratio (CNR) of a digital navigation signal are disclosed. The method includes: preprocessing a digital navigation signal to obtain a first in-phase component signal and a first quadrature component signal; removing modulation messages from the first in-phase component signal and the first quadrature component signal to obtain a second in-phase component signal and a second quadrature component signal; accumulating the second in-phase component signal and the second quadrature component signal to obtain the power of the second in-phase component signal and the power of the second quadrature component signal; performing a reliability estimation of the signal amplitude based on the power of the second in-phase component signal and the power of the second quadrature component signal, and the current phase-locked loop (PLL) state, to obtain an amplitude estimation result; and estimating the CNR of the digital navigation signal under the current PLL state based on the amplitude estimation result.

Description

TECHNICAL FIELD

[0001] The present application relates to signal processing technology, in particular to a method, device and storage medium for estimating carrier-to-noise ratio (CNR) of a digital navigation signal. BACKGROUND

[0002] It has become an important symbol of national science and technology level and comprehensive national strength to have a satellite navigation system. The Beidou-3 satellite navigation system has been formally put into operation, and its service range has expanded from the Asia-Pacific region to the global. Short message communication is a characteristic technology of the Beidou satellite navigation system. In addition to upgrading the existing regional short message satellite radio determination (RDSS) service, the Beidou-3 satellite navigation system also adds a global short message service through the B2b signal of the radio navigation satellite service (RNSS).

[0003] The RDSS service of the Beidou-3 satellite navigation system can currently support a single maximum of 1000 Chinese characters. While reducing the transmission power of the terminal, it also improves the capacity of the system inbound, and extends the original location report, emergency search and rescue, and communication services, providing necessary basic conditions for the subsequent comprehensive promotion and large-scale application of the RDSS service of the Beidou-3 satellite navigation system. The newly added global short message service of the Beidou-3 satellite navigation system provides services for global users through 14 medium earth orbit (MEO) satellites, with a maximum single message length of about 40 Chinese characters, which can truly realize that global users can tell others "where I am" and "what I am doing".

[0004] With the optimization of the Beidou-3 signal system and the improvement of information transmission rate, higher requirements are put forward for the receiving performance of the terminal, which usually needs to have higher tracking sensitivity. For the S2 signal of the RDSS of the Beidou-3 satellite navigation system, the message rate is as high as 32 kbps, and the message rate of the B2b signal of the RNSS is also as high as 1 kbps. For such high message rate navigation signals, if the existing carrier-to-noise ratio (CNR) calculation method is still used under high tracking sensitivity, a large calculation deviation will be generated. SUMMARY

[0005] The present application provides a method, device and storage medium for estimating CNR of a digital navigation signal, which can improve the estimation accuracy of CNR.

[0006] The method for estimating CNR of a digital navigation signal provided by the present application comprises the following steps:

[0007] The digital navigation signal is preprocessed to obtain a first in-phase component sub-signal and a first quadrature component sub-signal.

[0008] remove the modulated text from the first in-phase component sub-signal and the first quadrature component sub-signal to obtain a second in-phase component sub-signal and a second quadrature component sub-signal;

[0009] accumulate the second in-phase component sub-signal and the second quadrature component sub-signal to obtain a second in-phase component sub-signal power and a second quadrature component sub-signal power;

[0010] perform a reliability estimation on a signal amplitude according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and a current phase-locked loop state to obtain an estimation result of the amplitude;

[0011] estimate a digital navigation signal carrier-to-noise ratio in the current phase-locked loop state according to the estimation result of the amplitude.

[0012] Preferably, the first in-phase component sub-signal and the first quadrature component sub-signal obtained after the digital navigation signal is preprocessed include:

[0013] mix the digital navigation signal with a local carrier to achieve carrier stripping to obtain a baseband signal;

[0014] multiply the baseband signal by a local pseudo-code generated by a local pseudo-code generator to perform coherent processing to obtain the first in-phase component sub-signal and the first quadrature component sub-signal.

[0015] Preferably, the second in-phase component sub-signal and the second quadrature component sub-signal obtained by removing the modulated text from the first in-phase component sub-signal and the first quadrature component sub-signal include:

[0016] multiply the first in-phase component sub-signal and the first quadrature component sub-signal by a frequency multiplier to remove the modulated text from the first in-phase component sub-signal and the first quadrature component sub-signal to obtain the second in-phase component sub-signal and the second quadrature component sub-signal.

[0017] Preferably, the second in-phase component sub-signal power and the second quadrature component sub-signal power obtained by accumulating the second in-phase component sub-signal and the second quadrature component sub-signal include:

[0018] accumulate the second in-phase component sub-signal and the second quadrature component sub-signal according to a preset corresponding relationship between the digital navigation signal carrier-to-noise ratio and the number of accumulations, and square the accumulated results to obtain the second in-phase component sub-signal power and the second quadrature component sub-signal power.

[0019] Preferably, the preset corresponding relationship between the digital navigation signal carrier-to-noise ratio and the number of accumulations comprises:

[0020] The lower the value of the digital navigation signal carrier-to-noise ratio is, the more the number of accumulations is.

[0021] Preferably, the reliability of the signal amplitude is estimated according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and the current phase-locked loop state, and an estimation result of the amplitude is obtained, comprising:

[0022] In the case that the current phase-locked loop state is an unlocked state, the estimation result A of the signal amplitude is: est

[0023]

[0024] wherein, and respectively represent the second in-phase component sub-signal power and the second quadrature component sub-signal power, and M represents the number of accumulations.

[0025] Preferably, the digital navigation signal carrier-to-noise ratio in the current phase-locked loop state is estimated according to the estimation result of the amplitude, comprising:

[0026] In the case that the current phase-locked loop state is an unlocked state, the estimation result CN0 of the data navigation signal carrier-to-noise ratio is:

[0027]

[0028]

[0029] wherein, σ 2 is a noise power, and T is a digital navigation signal coherent integration time.

[0030] Preferably, the reliability of the signal amplitude is estimated according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and the current phase-locked loop state, and an estimation result of the amplitude is obtained, comprising:

[0031] In the case that the current phase-locked loop state is a locked state, the estimation result A of the signal amplitude is: est

[0032]

[0033] wherein, and respectively represent the second in-phase component sub-signal power and the second quadrature component sub-signal power, and M represents the number of accumulations.

[0034] ​​Preferably, the digital navigation signal carrier-to-noise ratio in the current phase-locked loop state is estimated according to the estimation result of the amplitude, comprising:

[0035] In the case that the current phase-locked loop state is a locked state, the estimation result CN0 of the data navigation signal carrier-to-noise ratio is:

[0036]

[0037] wherein σ 2 is a noise power, and T is a digital navigation signal coherent integration time.

[0038] Preferably, the type of the digital navigation signal comprises an S2 signal of satellite radio determination RDSS and a B2b signal of radio navigation satellite service RNSS.

[0039] The application further provides a computer readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the method according to any one of the preceding.

[0040] The application further provides a digital navigation signal carrier-to-noise ratio estimation device, which comprises a memory and a processor, and the memory stores a program, and the program is read and executed by the processor to implement the method according to any one of the preceding.

[0041] Compared with the related art, the technical solution of the application estimates the signal amplitude, and then estimates the carrier-to-noise ratio, which is flexible and simple to calculate. Moreover, the calculation bias caused by noise components is different in the locked state and the non-locked state of the phase-locked loop, which causes the signal amplitude to have biased estimation and approximately unbiased estimation in different phase-locked loop states. The embodiments of the application distinguish different phase-locked loop states to estimate the carrier-to-noise ratio, so that the estimation result is more accurate.

[0042] Other features and advantages of the application will be described in the following description, and some will become apparent from the description, or will be learned from the practice of the application. Other advantages of the application can be achieved and obtained through the solutions described in the specification and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0043] The accompanying drawings are used to provide an understanding of the technical solutions of the application, and constitute a part of the specification, and are used to explain the technical solutions of the application together with the embodiments of the application, and do not constitute a limitation on the technical solutions of the application.

[0044] Figure 1 A flowchart of the digital navigation signal carrier-to-noise ratio estimation method provided by the embodiments of the application is shown in the figure;

[0045] Figure 2 A comparison diagram of the carrier-to-noise ratio of the S2 signal of the RDSS estimated in the case of the phase-locked loop being unlocked and the carrier-to-noise ratio of the S2 signal of the RDSS estimated in the case of the phase-locked loop being locked is provided for the embodiments of the present application;

[0046] Figure 3 A comparison diagram of the carrier-to-noise ratio of the B2b signal of the RNSS estimated in the case of the phase-locked loop being unlocked and the carrier-to-noise ratio of the B2b signal of the RNSS estimated in the case of the phase-locked loop being locked is provided for the embodiments of the present application;

[0047] Figure 4 A module diagram of the estimation device of the carrier-to-noise ratio of the digital navigation signal is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0048] The present application describes multiple embodiments, but the description is exemplary rather than limiting, and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations can be within the scope of the embodiments described in the present application. Although many possible combinations of features are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are possible. Unless specifically intended otherwise, any feature or element of any embodiment can be used in combination with any other feature or element of any other embodiment, or in replacement of any other feature or element in any other embodiment.

[0049] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features, and elements disclosed in the present application can also be combined with any conventional features or elements to form unique inventive solutions defined by the claims. Any feature or element of any embodiment can also be combined with features or elements from other inventive solutions to form another unique inventive solution defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application can be implemented alone or in any appropriate combination. Embodiments are, therefore, not to be limited by other than in accordance with the limitations provided in the appended claims and their equivalents. Furthermore, various modifications and changes can be made within the scope of the claims.

[0050] Furthermore, in describing representative embodiments, the specification can have presented the method and / or process as a particular sequence of steps. However, to the extent that the method or process depends on the particular order of steps, this description should not be construed as limiting since other steps can be performed in other sequences and / or omitted from the method or process. Other steps can also be added to the method and / or process. The particular sequence of steps described should not be construed as limiting. The claims should not be limited to the steps in the particular order described in the specification. Further, the claims should not be limited to the particular order of steps as written in the claims. The claims should be interpreted as including the hardware and / or hardware and software combination that is equivalent to what is recited in the claims.

[0051] Embodiments of the present application provide a method for estimating carrier-to-noise ratio of digital navigation signal, as shown in the following figure, Figure 1 The method comprises the following steps:

[0052] In step S101, a first in-phase component sub-signal and a first quadrature component sub-signal are obtained after pre-processing of the digital navigation signal.

[0053] In step S102, a second in-phase component sub-signal and a second quadrature component sub-signal are obtained by removing modulation text in the first in-phase component sub-signal and the first quadrature component sub-signal.

[0054] In step S103, a second in-phase component sub-signal power and a second quadrature component sub-signal power are obtained by accumulating the second in-phase component sub-signal and the second quadrature component sub-signal.

[0055] In step S104, a reliability estimation of signal amplitude is performed according to the second in-phase component sub-signal power and the second quadrature component sub-signal power, and a current phase-locked loop state, to obtain an estimation result of the amplitude.

[0056] In step S105, a carrier-to-noise ratio of the digital navigation signal under the current phase-locked loop state is estimated according to the estimation result of the amplitude.

[0057] Embodiments of the present application provide a new carrier-to-noise ratio estimation method, which estimates signal amplitude and then estimates carrier-to-noise ratio, and is flexible and simple in calculation. Since the calculation bias caused by noise components is different in the locked state and the non-locked state of the phase-locked loop, the signal amplitude has biased estimation and approximately unbiased estimation in different phase-locked loop states. Embodiments of the present application distinguish different phase-locked loop states to estimate carrier-to-noise ratio, so that the estimation result is more accurate.

[0058] In an exemplary embodiment, the first in-phase component sub-signal and the first quadrature component sub-signal are obtained after pre-processing of the digital navigation signal, comprising:

[0059] Mixing the digital navigation signal with a local carrier to achieve carrier stripping to obtain a baseband signal;

[0060] Multiplying the baseband signal with a local pseudo code generated by a local pseudo code generator to obtain the first in-phase component sub-signal and the first quadrature component sub-signal through coherent processing, the first in-phase component sub-signal and the first quadrature component sub-signal being specifically:

[0061]

[0062]

[0063] Wherein, A is a signal amplitude, D is a modulated text ±1, Δω is a residual carrier frequency offset, T is a coherent integration time, is a residual carrier phase offset, R(Δτ) is a correlation peak generated by coherent processing, n I and n Q are noise powers, I1 is the first in-phase component sub-signal, and Q1 is the first quadrature component sub-signal.

[0064] In order to simplify the process, the influence of R(Δτ) on the amplitude is ignored here, the frequency deviation and the phase deviation are unified as a phase deviation Δθ, and then the above formula (1) and (2) can be simplified as:

[0065] I1=ADcos(Δθ)+n I (3)

[0066] Q1=ADsin(Δθ)+n Q (4)

[0067] In an exemplary embodiment, removing the modulated text in the first in-phase component sub-signal and the first quadrature component sub-signal to obtain a second in-phase component sub-signal and a second quadrature component sub-signal comprises:

[0068] Multiplying the first in-phase component sub-signal and the first quadrature component sub-signal respectively to remove the modulated text in the first in-phase component sub-signal and the first quadrature component sub-signal to obtain a second in-phase component sub-signal and a second quadrature component sub-signal.

[0069] Based on formula (3) and (4), in an exemplary embodiment, the method of multiplying the first in-phase component sub-signal and the first quadrature component sub-signal can be:

[0070]

[0071] Q2=2I1Q1=A 2 sin(2Δθ)+2Acos(Δθ)n Q+ 2Asin (Δθ)n I + n I + n Q (6)

[0072] After the above frequency multiplication processing, the modulated electric text D can be removed, and a second in-phase component sub-signal and a second quadrature component sub-signal are obtained, which are denoted as I2 and Q2 respectively.

[0073] In an exemplary embodiment, the second in-phase component sub-signal and the second quadrature component sub-signal are accumulated to obtain a second in-phase component sub-signal power and a second quadrature component sub-signal power, including:

[0074] The second in-phase component sub-signal and the second quadrature component sub-signal are accumulated according to a preset corresponding relationship between the digital navigation signal carrier-to-noise ratio and the number of accumulations, and the accumulated results are squared to obtain the second in-phase component sub-signal power and the second quadrature component sub-signal power.

[0075] Based on the formulas (5) and (6), the second in-phase component sub-signal power and the second quadrature component sub-signal power obtained are:

[0076]

[0077] wherein M represents the number of accumulations, I2 represents the second in-phase component sub-signal power, Q2 represents the second quadrature component sub-signal power; and the sum of the second in-phase component sub-signal power and the second quadrature component sub-signal power is the total signal power.

[0078] In an exemplary embodiment, the preset corresponding relationship between the digital navigation signal carrier-to-noise ratio and the number of accumulations includes that the lower the value of the digital navigation signal carrier-to-noise ratio, the more the number of accumulations. The lower the carrier-to-noise ratio value, the greater the influence of the noise signal, and the more useful signals need to be obtained through multiple accumulations.

[0079] Table 1 and Table 2 respectively show the corresponding relationship between the different carrier-to-noise ratios and the number of accumulations when the digital navigation signal is a satellite radio determination RDSS S2 signal and a radio navigation satellite service RNSS B2b signal. The corresponding relationship shown in Table 1 and Table 2 is obtained by the present inventor through a large amount of experimental data simulation.

[0080]

[0081] Table 1

[0082]

[0083] Table 2

[0084] In an example embodiment, a reliability estimation is made on the signal amplitude according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and the current phase-locked loop state, to obtain an estimation result of the amplitude, comprising:

[0085] In the case where the current phase-locked loop state is the unlocked state, the estimation result A est of the signal amplitude is:

[0086]

[0087] wherein, and respectively represent the second in-phase component sub-signal power and the second quadrature component sub-signal power, and M represents the number of accumulations. According to formula (9), when the phase-locked loop is in the unlocked state, the estimation process of A est is biased due to the influence of the noise component, and the estimation of the amplitude is a biased estimation.

[0088] In an example embodiment, a digital navigation signal carrier-to-noise ratio in the current phase-locked loop state is estimated according to the estimation result of the amplitude, comprising:

[0089] In the case where the current phase-locked loop state is the unlocked state, the estimation result CN0 of the digital navigation signal carrier-to-noise ratio is:

[0090]

[0091]

[0092] wherein, σ 2 is the noise power, and T is the digital navigation signal coherent integration time, which can be obtained by the coherent integration process of the digital navigation signal. At this time, the carrier-to-noise ratio is also a biased estimation, and the smaller the signal-to-noise ratio, the greater the bias. The estimation bias is caused by the high-order component of the noise component.

[0093] In an example embodiment, a reliability estimation is made on the signal amplitude according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and the current phase-locked loop state, to obtain an estimation result of the amplitude, comprising:

[0094] In the case where the current phase-locked loop state is the locked state, the estimation result A est of the signal amplitude is:

[0095]

[0096] wherein, and respectively represent the second in-phase component sub-signal power and the second quadrature component sub-signal power, and M represents the number of accumulations. When the phase-locked loop is in the locked state, the signal energy is concentrated in the in-phase component, and the quadrature component only contains noise. According to formula (11), it can be seen that the estimation process of the amplitude eliminates the noise 4A 2 Mσ 2 Therefore, the accuracy of the estimation result is better than the amplitude estimation result of the phase-locked loop in the unlocked state, and can be an approximately unbiased estimation.

[0097] In an exemplary embodiment, according to the estimation result of the amplitude, a digital navigation signal carrier-to-noise ratio in the current phase-locked loop state is estimated, comprising:

[0098] In the case where the current phase-locked loop state is the locked state, the estimation result CN0 of the data navigation signal carrier-to-noise ratio is:

[0099]

[0100] where σ 2 is the noise power, and T is the digital navigation signal coherent integration time. At this time, the estimation is an approximately unbiased estimation.

[0101] Figure 2 The estimation method of the carrier-to-noise ratio recorded in the embodiments of the present application is given, and the comparison between the estimated carrier-to-noise ratio of the S2 signal of the satellite radio measurement RDSS and the theoretical value of the carrier-to-noise ratio in the cases where the phase-locked loop is in the unlocked and locked states is shown in the schematic diagram. The theoretical value of the carrier-to-noise ratio is the signal carrier-to-noise ratio input in the simulation process, which is a known quantity. The carrier-to-noise ratio estimation method recorded in the embodiments of the present application is used to estimate the carrier-to-noise ratio of the known carrier-to-noise ratio signal, and the difference between the estimation result and the theoretical result is compared.

[0102] Figure 3 The estimation method of the carrier-to-noise ratio recorded in the embodiments of the present application is given, and the comparison between the estimated carrier-to-noise ratio of the B2b signal of the radio navigation satellite service RNSS and the theoretical value of the carrier-to-noise ratio in the cases where the phase-locked loop is in the unlocked and locked states is shown in the schematic diagram.

[0103] From Figure 2 and Figure 3 It can be seen that the carrier-to-noise ratio obtained according to the estimation method recorded in the embodiments of the present application is almost the same as the theoretical value of the carrier-to-noise ratio, and even in the case where the carrier-to-noise ratio is low, the accuracy of the estimated carrier-to-noise ratio can be ensured.

[0104] The embodiment of the present application further provides a computer readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the method according to any one of the preceding embodiments.

[0105] The embodiment of the present application further provides a device for estimating a digital navigation signal carrier-to-noise ratio, as shown in the accompanying drawings, the device comprises a memory 401 and a processor 402, the memory 401 stores a program, and the program is read and executed by the processor 402 to implement the method according to any one of the preceding embodiments. Figure 4

[0106] Those skilled in the art can understand that all or some of the steps in the method disclosed above, the functions of the modules / units in the system and the device can be implemented as software, firmware, hardware or a proper combination thereof. In the hardware implementation, the division between the function modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be performed by several physical components in cooperation. Some or all of the components can be implemented as software executed by a processor such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit such as an application-specific integrated circuit. Such software can be distributed on a computer readable medium, which can include computer storage media (or non-transitory media) and communication media (or transitory media). As known by those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. Furthermore, it is known by those skilled in the art that communication media typically includes computer readable instructions, data structures, program modules or other data in modulated data signals such as carrier waves or other transport mechanisms, and can include any information delivery medium.​

Claims

1. A method for estimating carrier-to-noise ratio of a digital navigation signal, comprising: obtaining a first in-phase component sub-signal and a first quadrature component sub-signal from a digital navigation signal after pre-processing; removing modulated text from the first in-phase component sub-signal and the first quadrature component sub-signal to obtain a second in-phase component sub-signal and a second quadrature component sub-signal; performing accumulation processing on the second in-phase component sub-signal and the second quadrature component sub-signal to obtain a second in-phase component sub-signal power and a second quadrature component sub-signal power; performing reliability estimation on a signal amplitude according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and a current phase-locked loop state to obtain an estimation result of the amplitude; performing biased estimation on the signal amplitude when the phase-locked loop is in an unlocked state; performing unbiased estimation on the signal amplitude when the phase-locked loop is in a locked state; estimating the carrier-to-noise ratio of the digital navigation signal in the current phase-locked loop state according to the estimation result of the amplitude.

2. The method of claim 1, wherein: the obtaining of the first in-phase component sub-signal and the first quadrature component sub-signal from the digital navigation signal after pre-processing comprises: mixing the digital navigation signal with a local carrier to achieve carrier stripping to obtain a baseband signal; multiplying the baseband signal with a local pseudo code generated by a local pseudo code generator to obtain the first in-phase component sub-signal and the first quadrature component sub-signal.

3. The method of claim 1, wherein: the removing of the modulated text from the first in-phase component sub-signal and the first quadrature component sub-signal to obtain the second in-phase component sub-signal and the second quadrature component sub-signal comprises: performing frequency multiplication processing on the first in-phase component sub-signal and the first quadrature component sub-signal respectively to remove the modulated text from the first in-phase component sub-signal and the first quadrature component sub-signal to obtain the second in-phase component sub-signal and the second quadrature component sub-signal.

4. The method of claim 1, wherein: the performing of the accumulation processing on the second in-phase component sub-signal and the second quadrature component sub-signal to obtain the second in-phase component sub-signal power and the second quadrature component sub-signal power comprises: performing accumulation on the second in-phase component sub-signal and the second quadrature component sub-signal according to a preset corresponding relationship between the carrier-to-noise ratio of the digital navigation signal and the number of accumulations, and performing square processing on the result after accumulation to obtain the second in-phase component sub-signal power and the second quadrature component sub-signal power.

5. The method of claim 4, wherein: the preset corresponding relationship between the carrier-to-noise ratio of the digital navigation signal and the number of accumulations comprises: the lower the value of the carrier-to-noise ratio of the digital navigation signal, the more the number of accumulations.

6. The method of claim 4, wherein: the performing of the reliability estimation on the signal amplitude according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and the current phase-locked loop state to obtain the estimation result of the amplitude comprises: In case the current phase-locked loop state is an unlocked state, the estimation result of the signal amplitude is: wherein, and respectively denote the second in-phase component sub-signal power and the second quadrature component sub-signal power, and M denotes the number of accumulations.

7. The method of claim 6, wherein, estimating the digital navigation signal carrier-to-noise ratio in the current phase-locked loop state according to the estimation result of the amplitude comprises: In the case that the current phase-locked loop state is an unlocked state, the estimation result of the digital navigation signal carrier-to-noise ratio is: / wherein is the noise power, T is the coherent integration time of the digital navigation signal.

8. The method of claim 4, wherein, reliability estimating the signal amplitude according to the second in-phase component sub-signal power and the second quadrature component sub-signal power and the current phase-locked loop state to obtain the estimation result of the amplitude comprises: In case the current phase-locked loop state is a locked state, the estimation result of the signal amplitude is: wherein, and respectively denote the second in-phase component sub-signal power and the second quadrature component sub-signal power, and M denotes the number of accumulations.

9. The method of claim 8, wherein, estimating the digital navigation signal carrier-to-noise ratio in the current phase-locked loop state according to the estimation result of the amplitude comprises: In the case that the current phase-locked loop state is a locked state, the estimation result of the digital navigation signal carrier-to-noise ratio is: wherein is the noise power, T is the coherent integration time of the digital navigation signal.

10. The method of any one of claims 1 to 9, wherein, the type of the digital navigation signal comprises an S2 signal of Satellite Radio Determination (RDSS) and a B2b signal of Radio Navigation Satellite Service (RNSS).

11. A computer-readable storage medium storing one or more programs, the one or more programs executable by one or more processors to implement the method of any one of claims 1 to 10.

12. An apparatus for estimating the carrier-to-noise ratio of a digital navigation signal, characterized by The device comprises a memory and a processor, the memory stores a program, and the program is read and executed by the processor to implement the method of any one of claims 1 to 10.

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