A satellite navigation high-sensitivity signal receiving method and system

Abstract

The present invention discloses a satellite navigation high-sensitivity signal receiving method and system. The received satellite signals are processed by a capture engine through coherent integration and non-coherent integration to obtain corresponding processing gains, and then the capture of the satellite signals is achieved. After the successful capture of the satellite signals, a high-sensitivity tracking channel and a high-precision tracking channel in a tracking acceleration engine are called corresponding to a preset adaptive scheduling strategy for signal tracking of the satellite signals. When the signal of the high-precision tracking channel is unlocked, the capture engine is directly used for relocking after unlocking. When the signal of the high-sensitivity tracking channel is unlocked, both the capture engine and the tracking acceleration engine are called for relocking after unlocking. Thus, under the condition of considering sensitivity, fast capture and fast relocking after unlocking of weak signals are achieved, and high-precision tracking and positioning can be maintained under strong signals.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a method and system for receiving satellite navigation high-sensitivity signals. Background Art

[0002] In environments such as valleys and forests, due to the influence of ionospheric refraction, multipath interference or external occlusion, etc., satellite signals will be greatly attenuated. Ordinary satellite navigation signal receivers will have problems such as difficult acquisition and easy loss of lock, and cannot work properly. It is necessary to improve the receiving sensitivity of the receiver.

[0003] The processing of satellite navigation signals by the receiver mainly includes two links: acquisition and tracking. Under weak signal conditions, for the initial acquisition, the receiver has less available prior information, the Doppler frequency and the range of pseudo-code phases to be searched are larger, and the computational complexity is high; for reacquisition after loss of lock, problems such as long acquisition time, high false alarm rate, and weak signal entry into lock will be faced; for tracking, under weak signal conditions, a frequency-locked loop is generally used to track the carrier, and its tracking sensitivity mainly depends on the pulling range of the frequency discriminator and the loop tracking accuracy. The pulling range is approximately inversely proportional to the pre-detection integration time of the loop. Therefore, it is difficult to improve the pulling range of the frequency discriminator and the loop tracking accuracy at the same time.

[0004] For the design of high-sensitivity receivers, long-time coherent integration and multiple non-coherent accumulations are generally used to achieve the gain of weak signals, and at the same time, a frequency-locked loop is considered to achieve higher-sensitivity signal tracking. Its defect is that the loss of lock time of the long-time coherent integration and non-coherent integration signals is longer, and the reacquisition after loss of lock of the signal cannot be achieved quickly. The positioning accuracy of using a frequency-locked loop for signal tracking is poor, and the positioning accuracy cannot quickly converge to the expected range when the signal changes from weak to strong.

[0005] At the same time, in practical applications, for handheld and other portable application terminals, it is necessary to achieve quick acquisition and quick reacquisition after loss of lock of weak signals while taking into account sensitivity as much as possible, and maintain high-precision tracking and positioning under strong signals. Therefore, the existing technologies and devices are difficult to balance sensitivity and quick signal acquisition and quick reacquisition after loss of lock, and are difficult to solve the problem of reduced service performance due to weak satellite signals in complex occlusion environments such as high-rise buildings and forests. Summary of the Invention

[0006] The main object of the present invention is to provide a new method and system for receiving satellite navigation high-sensitivity signals to solve the above technical problems.

[0007] To achieve the above object, a method for receiving satellite navigation high-sensitivity signals provided by the present invention includes the steps:

[0008] S1. The received satellite signals are processed by a capture engine through coherent integration and non - coherent integration to obtain corresponding processing gains, and then the capture of the satellite signals is achieved.

[0009] S2. After the successful capture of the satellite signals, a high - sensitivity tracking channel and a high - precision tracking channel in a tracking acceleration engine are called through a preset adaptive scheduling strategy for signal tracking of the satellite signals. Among them, the preset adaptive scheduling strategy includes that when the intensity of the satellite signals is lower than a preset threshold, the high - sensitivity tracking channel is used for signal tracking of the satellite signals, and when the intensity of the satellite signals is not lower than the preset threshold, the high - precision tracking channel is used for signal tracking of the satellite signals.

[0010] S3. When the signal of the high - precision tracking channel is out of lock, the capture engine is directly used for relocking after loss of lock.

[0011] S4. When the signal of the high - sensitivity tracking channel is out of lock, both the capture engine and the tracking acceleration engine are called for relocking after loss of lock.

[0012] Further, before step S1, it also includes: selecting the signal frequency point of the satellite signals. When the satellite signals are signals at a frequency point with a pilot branch, step S1 is entered.

[0013] Further, after the coherent integration and non - coherent integration processing in step S1, the total processing gain is G, and G = 10lg(BT coh ) + 10lg(N c ) - L sq ; where B is the bandwidth of the satellite signals, T coh is the coherent integration time, N c is the number of non - coherent integrations, and L sq is the square loss of non - coherent integration.

[0014] Further, the high - precision tracking channel uses a PPL third - order phase - locked loop (PLL) and a DLL first - order delay - locked loop, and the PPL third - order phase - locked loop assists the DLL first - order delay - locked loop to achieve high - precision tracking.

[0015] Further, the high - sensitivity tracking channel uses coherent integration and non - coherent integration techniques to improve the signal - to - noise ratio (SNR) of the signals, so as to achieve stable tracking of weak signals. The loop uses a second - order frequency - locked loop (FLL) and a second - order DLL in a cooperative manner.

[0016] Furthermore, the tracking acceleration engine uses 64 channels to integrate correlator data every millisecond or every 1 / 4 millisecond, and notifies the CPU by means of interruption or query.

[0017] Furthermore, the preset adaptive scheduling strategy includes one or more of the following state strategies:

[0018] Stage0: One-time traction is performed using a larger bandwidth FLL, FFT frequency discrimination is used, and the hardware coherent integration time needs to be 1 ms to ensure the maximum frequency discrimination range. After one-time traction is successful, BitSync starts.

[0019] Stage1: Two-time traction is also performed using a large bandwidth FLL, FFT frequency discrimination is used, and the hardware coherent integration time can be configured as 2 ms. After traction is completed, switch to the appropriate state according to the carrier-to-noise ratio C / N0. The mutual switching between each state can be performed according to C / N0.

[0020] Stage2: High-energy state, with the coherent integration time within 20 ms, and both PLL / FLL tracking are available.

[0021] Stage3: Medium-energy state, FLL tracking is used, FFT frequency discrimination is used, the coherent integration time is 20 ms, and the number of non-coherent times is 4 to 6 times.

[0022] Stage4: Low-energy state, FLL tracking is used, FFT frequency discrimination is used, the coherent integration time is 20 ms, and the number of non-coherent times is 12 to 16 times. The lowest C / N0 threshold can be configured according to the actual situation. If the real-time C / N0 is lower than the lowest C / N0, enter the reacquisition state ReAcq. If reacquisition is successful, switch to Stage1. If it fails, execute DelChan to delete the channel.

[0023] The present invention also provides a satellite navigation high-sensitivity signal receiving system, including.

[0024] A capture engine, which is used to perform coherent accumulation and non-coherent accumulation processing on the received satellite signal, obtain the corresponding processing gain, and then achieve the capture of the satellite signal;

[0025] A tracking acceleration engine is used to, after successful capture of the satellite signal, perform signal tracking of the satellite signal by calling a high-sensitivity tracking channel and a high-precision tracking channel within the tracking acceleration engine according to a preset adaptive scheduling strategy. Among them, the preset adaptive scheduling strategy includes: when the intensity of the satellite signal is lower than a preset threshold, using the high-sensitivity tracking channel to perform signal tracking of the satellite signal; when the intensity of the satellite signal is not lower than the preset threshold, using the high-precision tracking channel to perform signal tracking of the satellite signal; when the signal of the high-precision tracking channel is out of lock, directly performing out-of-lock reacquisition through the capture engine; when the signal of the high-sensitivity tracking channel is out of lock, simultaneously calling the capture engine and the tracking acceleration engine to perform out-of-lock reacquisition.

[0026] The present invention also provides a satellite navigation high-sensitivity signal receiving system, including a memory, a processor, a computer program stored in the memory and executable on the processor, and a controller for receiving instructions from the processor. It is characterized in that when the processor executes the computer program, the steps of the satellite navigation high-sensitivity signal receiving method described in any one of the above are implemented.

[0027] In the satellite navigation high-sensitivity signal receiving method and system of the technical solution of the present invention, the capture engine performs coherent accumulation and non-coherent accumulation processing on the received satellite signal to obtain a corresponding processing gain, and then realizes the capture of the satellite signal; after the successful capture of the satellite signal, the high-sensitivity tracking channel and the high-precision tracking channel within the tracking acceleration engine are called according to a preset adaptive scheduling strategy to perform signal tracking of the satellite signal. Among them, the preset adaptive scheduling strategy includes: when the intensity of the satellite signal is lower than a preset threshold, using the high-sensitivity tracking channel to perform signal tracking of the satellite signal; when the intensity of the satellite signal is not lower than the preset threshold, using the high-precision tracking channel to perform signal tracking of the satellite signal; when the signal of the high-precision tracking channel is out of lock, directly performing out-of-lock reacquisition through the capture engine; when the signal of the high-sensitivity tracking channel is out of lock, simultaneously calling the capture engine and the tracking acceleration engine to perform out-of-lock reacquisition. When the signal of the high-precision tracking channel is out of lock, directly perform out-of-lock reacquisition through the capture engine. When the high-sensitivity tracking channel is out of lock, simultaneously call the capture engine and the tracking acceleration engine to perform out-of-lock reacquisition at the same time, so as to ensure that the signal can be uploaded through the capture engine when a wrong lock or a large frequency deviation is found, and it can also ensure that the signal can achieve a higher-sensitivity reacquisition performance within a certain range, and realize fast out-of-lock reacquisition under weak signals.

[0028] The technical solution of the present invention has at least the following advantages:

[0029] 1. Achieve fast out-of-lock reacquisition under weak signals. The out-of-lock reacquisition is achieved through a capture engine and a tracking acceleration dual-engine. For directly calling the capture engine for out-of-lock reacquisition, signal capture within a relatively wide range can be achieved. For mislocked, interfering, and jittering signals, fast reacquisition and tracking can be achieved; for reacquisition by calling the tracking acceleration engine, reacquisition tracking with higher sensitivity performance can be achieved.

[0030] 2. Adaptively schedule strategies to achieve adaptive high-sensitivity signal tracking and out-of-lock reacquisition.

[0031] 3. Achieve high-sensitivity tracking in a weak signal environment and also achieve high-precision tracking in a normal signal environment.

[0032] 4. While taking sensitivity into account, achieve fast capture and fast out-of-lock reacquisition of weak signals, and maintain high-precision tracking and positioning under strong signals, improving the signal reception sensitivity and positioning availability of satellite navigation positioning devices such as handheld devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flowchart of the satellite navigation high-sensitivity signal reception method in an embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of the signal principle of the satellite navigation high-sensitivity signal reception method in an embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the module structure of the tracking acceleration engine in an embodiment of the present invention;

[0036] Figure 4 It is a schematic diagram of the hardware structure of a computer system running the satellite navigation high-sensitivity signal reception method in an embodiment of the present invention;

[0037] The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] In the following description, suffixes such as "module", "component", or "unit" used to represent elements are only for the convenience of describing the present invention, and they have no specific meaning themselves. Therefore, "module", "component", or "unit" can be used interchangeably.

[0040] Please refer to Figures 1-3, To achieve the above object, in the first embodiment of the present invention, a method for receiving satellite navigation high-sensitivity signals is provided, including the steps:

[0041] S1, Coherently accumulate and non-coherently accumulate the received satellite signals through a capture engine to obtain the corresponding processing gain, and then achieve the capture of the satellite signals;

[0042] S2, After the satellite signals are successfully captured, call the high-sensitivity tracking channel and the high-precision tracking channel in the tracking acceleration engine through a preset adaptive scheduling strategy to perform signal tracking on the satellite signals. Among them, the preset adaptive scheduling strategy includes that when the intensity of the satellite signals is lower than a preset threshold, the high-sensitivity tracking channel is used to perform signal tracking on the satellite signals, and when the intensity of the satellite signals is not lower than the preset threshold, the high-precision tracking channel is used to perform signal tracking on the satellite signals;

[0043] S3, When the high-precision tracking channel signal loses lock, directly perform relocking through the capture engine;

[0044] S4, When the high-sensitivity tracking channel signal loses lock, call the capture engine and the tracking acceleration engine simultaneously to perform relocking.

[0045] Further, before the step S1, it also includes: performing signal frequency point selection on the satellite signals. When the satellite signals are signals at frequency points with pilot branches, enter the step S1.

[0046] Specifically, first select the signal frequency points, and give priority to the frequency points with pilot branches, which can implement a relatively longer coherent integration time compared to other frequency points, without considering the influence of cross symbols, and the sensitivity performance and Doppler performance can be balanced by adjusting parameters.

[0047] Further, after performing the coherent accumulation and the non-coherent accumulation processing in the step S1, the total processing gain is G, G = 10lg(BT coh ) + 10lg(N c ) - L sq ; where B is the bandwidth of the satellite signals, T coh is the coherent integration time, N c is the number of non-coherent integrations, and L sq is the square loss of non-coherent integration.

[0048] Specifically, coherent integration can effectively improve the signal-to-noise ratio. Performing K times of coherent integration is equivalent to reducing the bandwidth to 1 / K of the original, and correspondingly reducing the noise energy to 1 / K of the original, thereby obtaining a gain of 10lg(K). For a satellite signal with a signal bandwidth of B, the processing gain of coherent integration for a time of T coh is:

[0049] G coh = 10lg(B * T coh )

[0050] The duration of coherent integration is restricted by the telemetry flip and frequency error, making its integration time unable to increase infinitely. The longer T coh is, under the condition of the same frequency error magnitude, the higher the attenuation degree of the coherent result generally is.

[0051] Non-coherent integration can further improve the signal-to-noise ratio. In the receiving channel, a pair of coherent integration results Ip(n) and Qp(n) are generated at intervals of one coherent integration time T coh on the branch, and then the corresponding autocorrelation amplitude P(n) is calculated. Non-coherent integration is to add and accumulate N c autocorrelation amplitudes P(n), that is

[0052]

[0053] For N c times of non-coherent accumulation, its gain is equal to the gain of coherent integration of the same number of times minus the square loss L sq of non-coherent accumulation, that is:

[0054] G ncs = 10lg(N c ) - L sq

[0055] The total processing gain after coherent and non-coherent accumulation is:

[0056] G = 10lg(BT coh and then10lg(N c sq

[0057] minus L ) - L sq

[0057] Then the signal-to-noise ratio SNR pd After coherent integration and non-coherent integration, its signal-to-noise ratio SNR is

[0058] SNR = SNR pd + G

[0059] The square loss stems from the squaring operation before integration in non-coherent integration. This squaring operation causes the mean value of the noise in the correlated signal power to be non-zero, and this kind of noise cannot be filtered by the integrator. The weaker the signal intensity, the greater the square loss, which in turn affects the acquisition sensitivity. To suppress the square loss, the signal must have a high signal-to-noise ratio before non-coherent integration. Selecting a longer coherent integration time can significantly improve the signal-to-noise ratio, but it is more likely to make the coherent integration affected by frequency errors. In practical applications, frequency offsets such as the stability of the crystal oscillator and the user's dynamics are inevitable. Therefore, it is necessary to select appropriate coherent integration time and non-coherent integration times to balance the attenuation caused by frequency errors and the square loss L sq between the contradictions.

[0060] The single-trial detection probability P d and the single-detection false alarm probability P fa are used to determine the performance of different detection decision techniques. In the background of additive white Gaussian noise, the signal s(t) passes through T coh time of coherent integration and N c times of non-coherent integration, and the detection quantity

[0061]

[0062] is obtained. Among them, I and Q are the results after IQ quadrature demodulation coherent integration at the receiver acquisition end, and v is the amplitude obtained after non-coherent accumulation. Under the ideal condition of white noise, assuming Nc = 1, when the signal does not exist, I and Q follow a normal distribution with a mean of 0 and a variance of , and I and Q are independent of each other, that is

[0063]

[0064]

[0065] where v ≥ 0, the signal energy a is 0, V follows a Rayleigh distribution, and the probability density function f n (v) is:

[0066]

[0067] When the signal exists, V follows a Rice distribution, and the probability density function f s (v) is:

[0068]

[0069] where v ≥ 0, is the first-kind zero-order Bessel function.

[0070] There exists a threshold that can be detected by the signal both under weak signals and strong signals. However, under strong signals, the setting of the threshold value is easier, which can better reduce or even avoid false alarms. By integrating the probability density function of V, the detection probability P of V under a specific threshold can be obtained, that is: t of V d , that is:

[0071]

[0072] Similarly, when there is no signal, set a = 0, and the false alarm probability P of a specific threshold can be obtained f .

[0073]

[0074] Only by increasing the signal-to-noise ratio SNR before detection can the detection probability P d and the false alarm probability P fa be balanced to improve the detection performance. For example, if the system requires P fa to be controlled below 10 -7 while the detection probability P d reaches more than 98%, then the pre-detection signal-to-noise ratio SNR needs to reach about 15 dB. In engineering practice, to achieve an acceptable receiver performance, the pre-detection signal-to-noise ratio is required to be at least 14 dB. At room temperature, the thermal noise power density is -174 dBm / Hz, the noise figure of the RF front end is assumed to be 2 dB, the quantization noise is 1 dB, the loss caused by residual Doppler is controlled at 1 dB, the loss caused by incomplete chip alignment is 1 dB, the satellite signal energy is P sat , then the signal-to-noise ratio SNR after coherent integration for a time of T coh and N c times of non-coherence is shown in the following formula.

[0075] SNR = P sat - (-174 + 2 - 10lgT coh ) + 10lg(N c ) - 3 - L sq

[0076] To obtain a signal-to-noise ratio of 14 dB, the minimum satellite signal energy can be obtained as follows:

[0077] P sat = (-174 + 2 - 10lg T coh ) - 10lg(N c ) + L sq + 3 + SNR.

[0078] Further, the high-precision tracking channel adopts a PPL third-order phase-locked loop (PLL) and a DLL first-order delay-locked loop, and the PPL third-order phase-locked loop assists the DLL first-order delay-locked loop to achieve high-precision tracking.

[0079] Further, the high-sensitivity tracking channel uses coherent integration and non-coherent integration techniques to improve the signal-to-noise ratio (SNR) of the signal, thereby achieving stable tracking of weak signals. The loop adopts a second-order frequency-locked loop (FLL) and a second-order DLL in cooperation.

[0080] Further, the tracking acceleration engine uses 64 channels to integrate correlator data every millisecond or every 1 / 4 millisecond, and notifies the CPU by means of interruption or query.

[0081] Specifically, the tracking acceleration engine module implements multi-channel tracking, provides correlator integration data of 64 channels every millisecond or every 1 / 4 millisecond, and notifies the CPU by means of interruption or query. The design block diagram of the tracking acceleration engine is as Figure 3 shown, and its functions include:

[0082] Coherent accumulation: Coherently accumulate the output results of all enabled correlators, and sequentially save the accumulation results for use as the input of non-coherent accumulation;

[0083] Smoothing power statistics on the peak correlator: Statistically calculate the power and total power of the peak correlator branch, and the sliding average coefficient is 1 / 2 a , and update the average value each time coherent accumulation is completed;

[0084] Calculation of wideband and narrowband power on the peak correlator: Accumulate the output results of the peak correlator for calculating the signal-to-noise ratio;

[0085] Non-coherent integration algorithm: Power, dot cross product, ordinary FFT, square FFT;

[0086] Coherently accumulated value on the peak correlator;

[0087] Non-coherent accumulation result;

[0088] Message demodulation.

[0089] Further, the preset adaptive scheduling strategy includes one or more of the following state strategies:

[0090] Stage0: One-time traction, carried out using a larger bandwidth FLL, using FFT frequency discrimination, and the hardware coherent integration time needs to be 1 ms to ensure the maximum frequency discrimination range. After one-time traction is successful, start BitSync.

[0091] Stage1: Secondary traction is also carried out using a large bandwidth FLL. FFT frequency discrimination is adopted, and the hardware coherent integration time can be configured as 2 ms. After the traction is completed, it switches to the appropriate state according to the carrier-to-noise ratio C / N0. The mutual switching between states can all be carried out according to C / N0.

[0092] Stage2: High energy state, within 20 ms of coherent integration time, both PLL / FLL tracking are available.

[0093] Stage3: Medium energy state, FLL tracking, FFT frequency discrimination is adopted, coherent integration time is 20 ms, and the number of non-coherent times is 4 - 6 times.

[0094] Stage4: Low energy state, FLL tracking, FFT frequency discrimination is adopted, coherent integration time is 20 ms, and the number of non-coherent times is 12 - 16 times. The lowest C / N0 threshold can be configured according to the actual situation. If the real-time C / N0 is lower than the lowest C / N0, it enters the reacquisition state ReAcq. If the reacquisition is successful, it switches to Stage1. If it fails, it executes DelChan to delete the channel.

[0095] The present invention also provides a satellite navigation high-sensitivity signal receiving system, including.

[0096] A capture engine, used to perform coherent accumulation and non-coherent accumulation processing on the received satellite signal, obtain the corresponding processing gain, and then achieve the capture of the satellite signal;

[0097] A tracking acceleration engine, used to, after the successful capture of the satellite signal, call the high-sensitivity tracking channel and the high-precision tracking channel in the tracking acceleration engine according to the preset adaptive scheduling strategy to perform signal tracking of the satellite signal. Among them, the preset adaptive scheduling strategy includes that when the intensity of the satellite signal is lower than the preset threshold, the high-sensitivity tracking channel is used to perform signal tracking of the satellite signal. When the intensity of the satellite signal is not lower than the preset threshold, the high-precision tracking channel is used to perform signal tracking of the satellite signal. When the signal of the high-precision tracking channel is out of lock, directly perform out-of-lock reacquisition through the capture engine. When the signal of the high-sensitivity tracking channel is out of lock, simultaneously call the capture engine and the tracking acceleration engine to perform out-of-lock reacquisition.

[0098] The present invention also provides a satellite navigation high-sensitivity signal receiving system, including a memory, a processor, a computer program stored in the memory and operable on the processor, and a controller for receiving instructions from the processor. It is characterized in that when the processor executes the computer program, it implements the steps of the satellite navigation high-sensitivity signal receiving method described in any one of the above.

[0099] The technical solution of the present invention has at least the following advantages:

[0100] 1. Achieve fast out-of-lock reacquisition under weak signals. The out-of-lock reacquisition is realized through a capture engine and a tracking acceleration dual-engine. For directly calling the capture engine for out-of-lock reacquisition, signal capture in a relatively wide range can be achieved, and for mislocked, interfering, and jumping signals, fast reacquisition and tracking can be realized; for the reacquisition of calling the tracking acceleration engine, reacquisition tracking with higher sensitivity performance can be realized.

[0101] 2. Adaptively schedule strategies to achieve adaptive high-sensitivity signal tracking and out-of-lock reacquisition.

[0102] 3. Achieve high-sensitivity tracking in a weak signal environment and also achieve high-precision tracking in a normal signal environment.

[0103] 4. While taking sensitivity into account, achieve fast capture and fast out-of-lock reacquisition of weak signals, and can maintain high-precision tracking and positioning under strong signals, improving the signal reception sensitivity and positioning availability of satellite navigation positioning devices such as handheld devices.

[0104] Exemplarily, the computer program of the computer-readable storage medium includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0105] In the description of this specification, the descriptions referring to terms such as "one embodiment", "another embodiment", "other embodiments", or "the first embodiment to the Xth embodiment", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, method steps, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0106] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0107] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are similarly included in the patent protection scope of the present invention.

Claims

1. A method for receiving satellite navigation signals with high sensitivity, characterized in that: Including steps: S1, performing coherent accumulation and incoherent accumulation processing on the received satellite signal through the capture engine to obtain corresponding processing gain, and then achieving capture of the satellite signal; S2, after the satellite signal is successfully captured, tracking the satellite signal by calling a high-sensitivity tracking channel and a high-precision tracking channel in the tracking acceleration engine corresponding to a preset adaptive scheduling strategy, wherein the preset adaptive scheduling strategy includes using the high-sensitivity tracking channel to track the satellite signal when the strength of the satellite signal is lower than a preset threshold, and using the high-precision tracking channel to track the satellite signal when the strength of the satellite signal is not lower than the preset threshold; S3, when the high-precision tracking channel signal loses lock, directly performing lock recapture through the capture engine; S4, when the high-sensitivity tracking channel signal loses lock, calling the capture engine and the tracking acceleration engine simultaneously to perform lock recapture.

2. The method for receiving satellite navigation signals with high sensitivity according to claim 1, wherein: Before step S1, the method further includes: selecting a signal frequency for the satellite signal, and entering step S1 when the satellite signal is a signal with a frequency having a pilot branch.

3. The method for receiving satellite navigation signals with high sensitivity according to claim 1, wherein: After the coherent accumulation and the incoherent accumulation in step S1, the total processing gain is G, G=101g (BT coh )+10lg(N c )-L sq ; Wherein, B is the bandwidth of the satellite signal, T coh is the coherent integration time, N c is the number of incoherent integrations, L sq is the square loss of the incoherent integration.

4. The method for receiving satellite navigation signals with high sensitivity according to claim 1, wherein: The high-precision tracking channel adopts a PPL third-order phase-locked loop phase-locked loop and a DLL first-order delay-locked loop, and the PPL third-order phase-locked loop phase-locked loop assists the DLL first-order delay-locked loop to achieve high-precision tracking.

5. The method for receiving satellite navigation signals with high sensitivity according to claim 1, wherein: The high-sensitivity tracking channel uses coherent integration and incoherent integration technology to improve the signal-to-noise ratio (SNR) of the signal, thereby achieving stable tracking of weak signals. The loop adopts a second-order frequency-locked loop (FLL) and a second-order DLL in combination.

6. The method for receiving satellite navigation signals with high sensitivity according to claim 4 or 5, characterized in that: The tracking acceleration engine uses 64 channels of correlator integration data on a millisecond or quarter-millisecond basis and notifies the CPU via interruption or query.

7. The method for receiving satellite navigation signals with high sensitivity according to claim 1, wherein: The preset adaptive scheduling strategy includes one or more of the following state strategies: Stage 0: A single pull is performed using a wide-bandwidth FLL and FFT frequency detection. The hardware coherent integration time must be 1ms to ensure the maximum frequency detection range. After a successful pull, BitSync begins. Stage 1: Secondary pull-in, also using a wide-bandwidth FLL and FFT frequency discrimination, with a hardware coherent integration time of 2ms. After pull-in, the system switches to the appropriate state based on the carrier-to-noise ratio (C / N0). Switching between states can be performed based on the C / N0. Stage 2: High energy state, coherent integration time within 20ms, PLL / FLL tracking is possible; Stage 3: Medium energy state, FLL tracking, using FFT frequency detection, coherent integration time 20ms, and incoherent times 4 to 6 times; Stage 4: Low energy state, FLL tracking, using FFT frequency detection, coherent integration time 20ms, incoherent number of times 12 to 16 times; the minimum C / N0 threshold can be configured according to actual conditions. If the real-time C / N0 is lower than the minimum C / N0, the system enters the recapture state ReAcq. If the recapture is successful, it switches to Stage 1. If it fails, it executes DelChan and deletes the channel.

8. A satellite navigation high-sensitivity signal receiving system, characterized in that: include: A capture engine, configured to perform coherent accumulation and incoherent accumulation processing on received satellite signals to obtain corresponding processing gains, and then to capture the satellite signals; a tracking acceleration engine, configured to, after successfully capturing the satellite signal, correspondingly call a high-sensitivity tracking channel and a high-precision tracking channel within the tracking acceleration engine according to a preset adaptive scheduling strategy to track the satellite signal, wherein the preset adaptive scheduling strategy includes using the high-sensitivity tracking channel to track the satellite signal when the strength of the satellite signal is below a preset threshold, and using the high-precision tracking channel to track the satellite signal when the strength of the satellite signal is not below the preset threshold; When the high-precision tracking channel signal loses lock, the capture engine is directly used to perform recapture; when the high-sensitivity tracking channel signal loses lock, the capture engine and the tracking acceleration engine are simultaneously called to perform recapture.

9. A satellite navigation high-sensitivity signal receiving system, characterized in that: The method comprises a memory, a processor, a computer program stored in the memory and executable on the processor, and a controller for receiving instructions from the processor, wherein the processor implements the steps of the satellite navigation high-sensitivity signal receiving method as claimed in any one of claims 1 to 7 when executing the computer program.

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