Method for tracking navigation signal from fused signal and navigation positioning method

Abstract

The invention relates to the technical field of satellite navigation, and discloses a method for tracking a navigation signal from a fusion signal and a navigation positioning method, the fusion signal comprises a navigation signal sent by a satellite in a navigation time slot and a non-navigation signal sent in a non-navigation time slot, and the method comprises the following steps: responding to the received navigation signal; inputting the navigation signal into a feedback correction loop, and adjusting a local carrier frequency output by a local oscillator by the feedback correction loop based on the carrier frequency of the navigation signal to obtain a tracking signal of the navigation signal; and in response to the received non-navigation signal, estimating the carrier frequency of the target navigation signal after the non-navigation signal, and taking the estimation result as the initial local carrier frequency output by the local oscillator when the target navigation signal is tracked. The tracking efficiency of navigation signals can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of satellite navigation technology, and in particular to a method for tracking a navigation signal from a fused signal and a navigation positioning method. Background Art

[0002] The orbit of low-orbit satellites is low, and the satellite's speed and geometric position change relatively quickly. Based on the navigation signals of low-orbit satellites, the navigation equipment on the ground can observe a larger Doppler frequency shift, which is conducive to improving the navigation positioning accuracy of the navigation equipment and the integer ambiguity resolution during carrier phase positioning. In addition, the propagation loss of the navigation signals of low-orbit satellites in space is also less, the signal landing power is higher and the ability to suppress interference is stronger, which is conducive to improving the tracking and capture performance of the navigation equipment.

[0003] However, precisely because of the high dynamic characteristics of low-orbit satellites (i.e., the geometric position changes rapidly), traditional navigation equipment finds it difficult to achieve rapid convergence in a short period of time when tracking the navigation signals sent by low-orbit satellites, thereby reducing the signal tracking efficiency.

[0004] Therefore, there is an urgent need for a method that can improve the efficiency of navigation signal tracking. Summary of the invention

[0005] In view of this, the present disclosure provides a method for tracking a navigation signal from a fused signal, a navigation positioning method, an apparatus for tracking a navigation signal from a fused signal, a navigation positioning apparatus, an electronic device and a computer-readable storage medium, which can improve the tracking efficiency of the navigation signal.

[0006] In a first aspect, the present disclosure provides a method for tracking a navigation signal from a fused signal, wherein the fused signal includes a navigation signal sent by a satellite in a navigation time slot and a non-navigation signal sent in a non-navigation time slot, the method comprising: In response to receiving the navigation signal, inputting the navigation signal into a feedback correction loop, wherein the feedback correction loop adjusts a local carrier frequency output by a local oscillator based on the carrier frequency of the navigation signal to obtain a tracking signal of the navigation signal; In response to receiving the non-navigation signal, a carrier frequency of a target navigation signal following the non-navigation signal is estimated, and the estimation result is used as an initial local carrier frequency output by the local oscillator when tracking the target navigation signal.

[0007] In a second aspect, the present disclosure provides a navigation and positioning method, the method comprising: Extracting Doppler data for navigation positioning from a tracking signal of the navigation signal, wherein the tracking signal is obtained based on the method of tracking the navigation signal from the fusion signal described above; Divide the designated ground into a plurality of grids, and determine a theoretical signal Doppler value at each grid based on a grid center position of each grid and a velocity position of a satellite; According to the actual signal Doppler value at each grid, find the target grid with the smallest difference between the theoretical signal Doppler value and the actual signal Doppler value; Based on the Doppler data, a least squares iterative model is constructed, and the position of the target grid is used as an initial position value to solve the least squares iterative model to obtain navigation positioning information.

[0008] In a third aspect, the present disclosure provides a device for tracking a navigation signal from a fused signal, wherein the fused signal includes a navigation signal sent by a satellite in a navigation time slot and a non-navigation signal sent in a non-navigation time slot, and the device includes: a feedback correction module, configured to input the navigation signal into a feedback correction loop in response to receiving the navigation signal, and adjust the local carrier frequency output by the local oscillator based on the carrier frequency of the navigation signal by the feedback correction loop to obtain a tracking signal of the navigation signal; The output correction module is used for estimating the carrier frequency of the target navigation signal after the non-navigation signal in response to receiving the non-navigation signal, and using the estimation result as the initial local carrier frequency output by the local oscillator when tracking the target navigation signal.

[0009] In a fourth aspect, the present disclosure provides a navigation and positioning device, the device comprising: A data extraction module, used to extract Doppler data for navigation positioning from a tracking signal of a navigation signal, wherein the tracking signal is obtained based on the method of tracking a navigation signal from a fusion signal as described above; A grid division module, used for dividing the designated ground into a plurality of grids, and determining a theoretical signal Doppler value at each grid based on the grid center position of each grid and the velocity position of the satellite; A grid search module is used to search for a target grid having the smallest difference between a theoretical signal Doppler value and an actual signal Doppler value according to the actual signal Doppler value at each grid; The model building module is used to build a least squares iterative model based on the Doppler data, and use the position of the target grid as the initial position value to solve the least squares iterative model to obtain navigation positioning information.

[0010] In a fifth aspect, the present disclosure provides an electronic device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, computer instructions are stored in the memory, and the processor executes the above method by executing the computer instructions.

[0011] In a sixth aspect, the present disclosure provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the above method.

[0012] In the technical solutions of some embodiments of the present disclosure, when a non-navigation signal is received, the local carrier frequency output by the local oscillator can be adjusted in the non-navigation time slot by estimating the carrier frequency of the target navigation signal after the navigation signal, so that after entering the navigation time slot, the navigation signal can be directly input into the feedback correction loop, without the problem that after entering the navigation time slot, the local carrier frequency output by the local oscillator needs to be adjusted in real time according to the target navigation signal before the navigation signal can be input into the feedback correction loop as in some technologies. Therefore, the solution of the present disclosure can reduce the time consumption in the navigation time slot, thereby improving the tracking efficiency of the navigation signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 is a schematic diagram of a module of a tracking loop included in a navigation device in some technologies; Figure 2 It is a schematic diagram of the time slots when the satellite communicates with multiple ground devices in some scenarios; Figure 3 It is a schematic diagram of navigation signal tracking by navigation equipment in some technologies; Figure 4 It is a schematic diagram of the adjustment of the local carrier frequency by navigation equipment in some technologies; Figure 5 is a flowchart of a method for tracking a navigation signal from a fusion signal provided by an embodiment of the present disclosure; Figure 6 is a schematic diagram of a navigation device performing navigation signal tracking according to an embodiment of the present disclosure; Figure 7 is a schematic diagram of adjusting a local carrier frequency by a navigation device provided by an embodiment of the present disclosure; Figure 8 This is the process intention of the navigation and positioning method provided by an embodiment of the present disclosure; Fig. 9 It is a module schematic diagram of an apparatus for tracking a navigation signal from a fusion signal provided by an embodiment of the present disclosure; Fig.10 is a module schematic diagram of a navigation and positioning device provided by an embodiment of the present disclosure; Fig.11 It is a schematic diagram of the structure of an electronic device provided by some embodiments of the present disclosure. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0016] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0017] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "some embodiments" or "the embodiment" should be understood as "at least some embodiments". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions may also be included below.

[0018] Herein, unless explicitly stated, executing a step “in response to A” does not mean executing the step immediately after “A” but may include one or more intermediate steps.

[0019] It is understandable that the data involved in this technical solution (including but not limited to the data itself, the acquisition, use, storage or deletion of the data) shall comply with the requirements of relevant laws, regulations and relevant provisions.

[0020] It is understandable that before using the technical solutions disclosed in the various embodiments of the present disclosure, the types, scopes of use, usage scenarios, etc. of the information involved in the present disclosure should be informed to relevant users and their authorization should be obtained in an appropriate manner in accordance with relevant laws and regulations. The relevant users may include any type of right holders, such as individuals, enterprises, and groups.

[0021] For example, in response to receiving an active request from a user, a prompt message is sent to the relevant user to clearly prompt the relevant user that the operation requested to be performed will require obtaining and using the information of the relevant user, so that the relevant user can independently choose whether to provide information to software or hardware such as an electronic device, application, server or storage medium that executes the operation of the technical solution of the present disclosure based on the prompt message.

[0022] As an optional but non-limiting implementation, in response to receiving an active request from a relevant user, a prompt message is sent to the relevant user, for example, in the form of a pop-up window, in which the prompt message may be presented in text form. In addition, the pop-up window may also carry a selection control for the user to select "agree" or "disagree" to provide information to the electronic device.

[0023] It is understandable that the above notification and the process of obtaining user authorization are merely illustrative and do not constitute a limitation on the implementation of the present disclosure. Other methods that meet relevant laws and regulations may also be applied to the implementation of the present disclosure.

[0024] When there is relative motion between the transmitting source (such as a satellite) and the receiving object (such as a navigation device), there will be a difference between the frequency of the signal received by the receiving object and the frequency of the signal emitted by the transmitting source. This frequency difference is called the Doppler shift. For example, when the transmitting source sends a signal at a frequency of 100 kHz, if there is relative motion between the transmitting source and the receiving object, the frequency of the signal received by the receiving object may be 90 kHz. The frequency difference of 10 kHz is called the Doppler shift. Generally speaking, the greater the relative motion speed between the transmitting source and the receiving object, the more obvious the corresponding Doppler shift.

[0025] The principle of navigation positioning based on Doppler frequency shift is as follows: the navigation device tracks the navigation signal sent by the satellite to obtain the corresponding tracking signal. By performing steps such as demodulation and frequency measurement on the tracking signal, Doppler data including Doppler frequency shift can be extracted from the tracking signal. Based on the Doppler data, the relative speed between the satellite and the navigation device can be calculated. Based on the relative speed between the navigation device and multiple satellites, or based on the relative speed between the navigation device and the same satellite at multiple time points, the specific location of the navigation device can be determined.

[0026] Combined with reference Figure 1 , which is a module diagram of a tracking loop included in a navigation device in some technologies. Figure 1In the tracking loop, the tracking loop includes a feedback correction loop and a local oscillator. The feedback correction loop includes a mixer, an integrator, a phase detector and a loop filter. The mixer is used to mix the navigation signal received by the navigation device with the local carrier signal generated by the local oscillator, and output an intermediate frequency signal. The intermediate frequency signal may include frequency difference information and phase difference information between the navigation signal and the local carrier signal. The integrator is used to integrate the intermediate frequency signal output by the mixer. Through the integration process, the noise and interference in the intermediate frequency signal can be smoothed, and the signal-to-noise ratio of the intermediate frequency signal can be improved, thereby enhancing the anti-interference ability of the tracking loop. The phase detector is used to determine the phase difference between the navigation signal carrier and the local carrier signal based on the intermediate frequency signal after the integration process, and output an error signal (such as a voltage signal) proportional to the phase difference. The loop filter can smooth the error signal and remove high-frequency noise and interference. The error signal processed by the loop filter can be used to control the local oscillator to reduce the phase difference between the navigation signal carrier and the local carrier signal.

[0027] When the phase difference between the navigation signal carrier and the local carrier signal is less than the phase difference threshold, it indicates that the tracking loop has converged. After the tracking loop converges, the frequency difference between the navigation signal carrier and the local carrier signal can be less than the frequency difference threshold, that is, the navigation signal carrier and the local carrier signal are synchronized. After carrier synchronization, the difference frequency component (i.e., baseband signal) in the intermediate frequency signal output by the mixer becomes obvious. By further signal processing (such as demodulation, decoding, etc.) of the difference frequency component, the information signal modulated on the navigation signal carrier can be extracted to obtain the Doppler data used for navigation positioning.

[0028] In some scenarios, a satellite communicates with multiple ground devices (such as navigation equipment and communication equipment) in a time division multiplexing communication mode. In this communication mode, the satellite and each ground device have their own corresponding time slots. For example, in conjunction with Figure 2 , which is a schematic diagram of the time slots when the satellite communicates with multiple ground devices in some scenarios. Figure 2 In the time slot, the time slot includes the navigation time slot and the communication time slot. In the navigation time slot, the satellite can send navigation signals to the navigation device; in the communication time slot, the satellite can send communication signals to the communication device. That is, the satellite can send navigation signals and communication signals to different ground devices alternately according to the time slot. For example, the satellite can send navigation signals to the navigation device between 20 milliseconds and 40 milliseconds; send communication signals to the communication device between 40 milliseconds and 100 milliseconds; send navigation signals to the navigation device between 100 milliseconds and 120 milliseconds. And so on. The parsing methods of navigation signals and communication signals can be different.

[0029] Combined with reference Figure 3In some technologies, the navigation device can continuously receive signals sent by satellites. If the signal received by the navigation device is usable (i.e., the navigation device can parse the received signal), it indicates that the navigation time slot has entered, and the navigation signal can be input into the feedback correction loop, so that the navigation signal can be corrected according to the feedback correction loop. Figure 1 According to the principle described above, the navigation signal is tracked; if the signal received by the navigation device is unavailable (i.e., the navigation device cannot parse the received signal), it indicates that the communication time slot has been entered, and the signal can continue to be received, and the received signal is not input into the feedback correction loop. For example, between 40 milliseconds and 100 milliseconds, the navigation device receives a communication signal. Since the navigation device cannot parse the communication signal (i.e., the received signal is unavailable), the navigation device can determine that the current time slot is not a navigation time slot. For another example, between 100 milliseconds and 120 milliseconds, the navigation device receives a navigation signal. Since the navigation device can parse the navigation signal (i.e., the received signal is available), the navigation device can determine that the current time slot is a navigation time slot.

[0030] Furthermore, in some technologies, the satellite that sends the navigation signal may be a low-orbit satellite. Due to the high dynamic characteristics of low-orbit satellites, the Doppler frequency shift in two adjacent navigation time slots may be greatly different, that is, the carrier frequency of the navigation signal received by the navigation device in two adjacent navigation time slots may be greatly different. For example Figure 4In the figure, the dotted line ACEF can represent the carrier frequency change trend of the navigation signal received by the navigation device during the navigation time slot T1-T2. The solid line BCDF can represent the change trend of the local carrier frequency output by the local oscillator. It can be seen from the dotted line ACEF that at the end of the navigation time slot T1, the carrier frequency of the navigation signal received by the navigation device is located at position C, but after passing through the communication time slot T3 and entering the navigation time slot T2, the carrier frequency of the navigation signal received by the navigation device changes to position E. There is a large difference between the carrier frequencies of the navigation signals at positions E and C. As for the local carrier frequency output by the local oscillator, at the end of the navigation time slot T1, the local carrier frequency output by the local oscillator is located at position C. Since the navigation signal will not be tracked in the communication time slot T3, the local carrier frequency output by the local oscillator will not be adjusted. Therefore, when entering the navigation time slot T2, the local carrier frequency output by the local oscillator is still located at position C. Since the difference between the carrier frequencies at position C and position E is large, the local carrier frequency output by the local oscillator needs to be adjusted multiple times through the feedback correction loop, so that the local carrier frequency output by the local oscillator can be consistent with the carrier frequency of the navigation signal (or the difference between the two is within the threshold range) within the navigation time slot T2. This time consumption is relatively long, even longer than the duration of the navigation time slot T2, which results in that the local carrier frequency output by the local oscillator may not be adjusted to be consistent with the carrier frequency of the navigation signal when the navigation time slot T2 is over, resulting in the problem of navigation signal tracking failure.

[0031] In view of this, in some technologies, in the case of navigation positioning based on low-orbit satellites, the navigation signal sent by the satellite can be a STL (Satellite Time and Location) pulse signal modulated using 25 kHz QPSK (Quadrature Phase Shift Keying). The QPSK data at the beginning of the STL pulse signal can be designed as a continuous wave (CW) for pulse detection and rough measurement of the carrier frequency. The remaining QPSK data in the STL pulse signal except the beginning can be organized in a pseudo-random sequence. In each navigation time slot, before the navigation signal is input into the feedback correction loop, the navigation device can capture the continuous wave at the beginning of the navigation signal and perform a discrete Fourier transform on the continuous wave to obtain an estimated value of the carrier frequency of the navigation signal. Based on the estimated value, the local oscillator can be controlled to output a local carrier frequency that is the same as the estimated value. In this way, after the navigation signal is input into the feedback correction loop, the local carrier frequency output by the local oscillator will not differ too much from the carrier frequency of the navigation signal, and the tracking loop will converge after adjustment by the feedback correction loop. Figure 4In the figure, it is assumed that after entering the navigation time slot T2, by capturing the continuous wave at the starting position of the navigation signal, it is estimated that the carrier frequency of the navigation signal is at position D, then the local oscillator can be controlled to increase the local carrier frequency output by the local oscillator from position C to position D. In this way, after the navigation signal is input into the feedback correction loop, the actual carrier frequency of the navigation signal is at position E, and the local carrier frequency is at position D. Since the two carrier frequencies are not much different, the tracking loop will converge quickly, thereby improving the tracking success rate of the navigation signal.

[0032] exist Figure 4 In the scheme shown, each time entering the navigation time slot, it is necessary to capture the continuous wave at the start bit end of the navigation signal, and perform discrete Fourier transform on the captured continuous wave to obtain an estimated value of the navigation signal carrier frequency, and before inputting the navigation signal into the feedback correction loop, adjust the local carrier frequency output by the local oscillator based on the estimated value of the navigation signal carrier frequency. This process takes a relatively long time. On the one hand, it greatly reduces the tracking efficiency of the navigation signal. On the other hand, in this time-division multiplexing communication scenario, the duration of a navigation time slot is usually relatively short, which will cause greater pressure on the tracking of the navigation signal. For example, it is possible to exit the navigation time slot before obtaining the estimated value of the navigation signal carrier frequency, resulting in the problem of navigation signal tracking failure.

[0033] In view of this, the present disclosure provides a method for tracking a navigation signal from a fused signal, which can solve the above problems and improve the tracking efficiency of the navigation signal. The fused signal includes a navigation signal sent by a satellite in a navigation time slot and a non-navigation signal sent in a non-navigation time slot. The satellite may be a low-orbit satellite. The non-navigation signal may include but is not limited to a communication signal. The method of the present disclosure can be applied to a navigation device. In the navigation device, a tracking loop for tracking the navigation signal may be included.

[0034] Combined with reference Figure 5 and Figure 6 In one embodiment of the present disclosure, a method for tracking a navigation signal from a fusion signal may include the following steps: Step S501, in response to receiving a navigation signal, inputting the navigation signal into a feedback correction loop, and the feedback correction loop adjusts the local carrier frequency output by the local oscillator based on the carrier frequency of the navigation signal to obtain a tracking signal of the navigation signal.

[0035] Step S502, in response to receiving the non-navigation signal, estimating the carrier frequency of the target navigation signal following the non-navigation signal, and using the estimation result as the initial local carrier frequency output by the local oscillator when tracking the target navigation signal.

[0036] Specifically, with Figure 3 Similarly, if the signal received by the navigation device is a usable signal, indicating that it has entered a navigation time slot, and the received signal is a navigation signal, step S501 can be executed; if the signal received by the navigation device is an unusable signal, indicating that it has entered a non-navigation time slot, and the received signal is a non-navigation signal, step S502 can be executed.

[0037] In this embodiment, in response to receiving a non-navigation signal, the carrier frequency of the target navigation signal after the non-navigation signal can be estimated based on a constructed estimation model. The estimation model can be constructed based on the carrier frequency variation trend of the historical navigation signal received by the navigation device. For example, an estimation model can be constructed based on a time series algorithm and the carrier frequency variation trend of the historical navigation signal. In the subsequent embodiments of the present disclosure, a preferred estimation model construction method is provided, which is not described in detail here.

[0038] Combined with reference Figure 4 and Figure 7 . The main difference between the method disclosed in the present invention and some technologies is that in some technologies, the control of the local oscillator is performed after entering the navigation time slot. In other words, in the communication time slot, no adjustment will be made to the local carrier frequency output by the local oscillator. In this way, after entering the navigation time slot, time will be wasted to capture the continuous wave of the navigation signal and perform discrete Fourier transform on the continuous wave, resulting in the problem of low navigation signal tracking efficiency. In the method disclosed in the present invention, in the communication time slot, the carrier frequency of the next target navigation signal will be estimated, and the local carrier frequency output by the local oscillator will be adjusted according to the estimated carrier frequency. In this way, when entering the navigation time slot after the communication time slot, the local carrier frequency is already close to the carrier frequency of the navigation signal, and there is no need to waste time to capture the continuous wave and perform discrete Fourier transform on the continuous wave, thereby improving the tracking efficiency of the navigation signal.

[0039] For ease of understanding, Figure 4 and Figure 7 The difference between the present disclosure and some other technologies can also be seen from the comparison. Figure 4 It can be seen from the communication time slot T3 that the local carrier frequency output by the local oscillator is a straight line, indicating that in the communication time slot T3, the local carrier frequency output by the local oscillator is not adjusted and the local carrier frequency does not change. Figure 7It can be seen from the communication time slot T3 that the local carrier frequency output by the local oscillator changes from position C to position D, indicating that in the communication time slot T3, according to the estimated result in step S502, the local carrier frequency output by the local oscillator has been adjusted, so that when entering the navigation time slot T2, the local carrier frequency output by the local oscillator is already close to the carrier frequency of the target navigation signal. Therefore, the navigation signal can be directly input into the feedback correction loop without wasting time capturing the continuous wave and performing discrete Fourier transform on the continuous wave.

[0040] In summary, in the technical solutions of some embodiments of the present disclosure, when a non-navigation signal is received, the local carrier frequency output by the local oscillator can be adjusted in the non-navigation time slot by estimating the carrier frequency of the target navigation signal after the navigation signal, so that after entering the navigation time slot, the navigation signal can be directly input into the feedback correction loop, without the problem that after entering the navigation time slot, the local carrier frequency output by the local oscillator needs to be adjusted in real time according to the target navigation signal before the navigation signal can be input into the feedback correction loop as in some technologies. Therefore, the solution of the present disclosure can reduce the time consumption in the navigation time slot, thereby improving the tracking efficiency of the navigation signal.

[0041] In some embodiments, based on the tracking method disclosed in the present invention, in the first navigation time slot, the feedback correction loop needs about 40 milliseconds to achieve convergence, and in other navigation time slots other than the first navigation time slot, the feedback correction loop needs about 10 milliseconds to achieve convergence. It can also be seen from such data comparison that the method disclosed in the present invention can greatly improve the tracking efficiency of the navigation signal.

[0042] In some embodiments, Figure 6 In the embodiment, the carrier frequency estimation module and each module in the feedback correction loop may be a software code module running in the navigation device, and the local oscillator may be a hardware module arranged in the navigation device.

[0043] Further, see Figure 7 . In some embodiments, considering that the carrier frequency change trend of the historical navigation signal may not be obtained in the first navigation time slot, the local carrier frequency output by the local oscillator can be adjusted in the first navigation time slot based on methods in some technologies to ensure the normal tracking function of the navigation signal. In other navigation time slots after the first navigation time slot, since there is already a carrier frequency change trend of the historical navigation signal (for example, the navigation signal in the first navigation time slot can be used as a historical navigation signal), the local carrier frequency output by the local oscillator can be adjusted based on the method disclosed in the present invention to improve the tracking efficiency of the navigation signal.

[0044] Furthermore, on the one hand, considering that obtaining the carrier frequency of the historical navigation signal may involve relatively complex calculations; on the other hand, when the feedback correction loop reaches a convergence state, the local carrier frequency output by the local oscillator is synchronized with the carrier frequency of the navigation signal. Therefore, in other navigation time slots after the first navigation time slot, the carrier frequency of the target navigation signal after the non-navigation signal can be estimated based on the change trend of the local carrier frequency in the historical navigation time slot. Compared with obtaining the carrier frequency of the historical navigation signal, the local carrier frequency is data that can be directly obtained when controlling the local oscillator, so the difficulty of implementing the solution can be reduced.

[0045] Based on the above description, estimating the carrier frequency of the target navigation signal after the non-navigation signal in step S502 may include: If the target navigation signal is a navigation signal received in the first navigation time slot, a continuous wave at a specified position in the target navigation signal can be captured; The captured continuous wave is subjected to discrete Fourier transform to obtain an estimate of the carrier frequency of the target navigation signal.

[0046] Specifically, similar to some technologies, the continuous wave at the start bit end of the target navigation signal can be captured to estimate the estimated value of the carrier frequency of the target navigation signal. The relevant principles are not described in detail here.

[0047] Further, if the target navigation signal is a navigation signal received in other target navigation time slots other than the first navigation time slot, an estimation model is constructed based on a correspondence between a local carrier frequency and a time point in at least one navigation time slot before the target navigation time slot; The starting time point of the target navigation time slot is input into the estimation model, and the estimation model outputs the estimated value of the carrier frequency of the target navigation signal.

[0048] Specifically, in the correspondence between the local carrier frequency and the time point, the time point is counted based on the time point when the tracking loop is started. For example, the time point may be the 2nd second, 3rd second, 4th second, etc. after the tracking loop is started. And so on.

[0049] Furthermore, since the local carrier frequency and the carrier frequency of the navigation signal may differ when the feedback correction loop has not reached a convergence state, for the sake of data accuracy, in any navigation time slot, the corresponding relationship between the local carrier frequency and the time point can be triggered to be collected when the feedback correction loop reaches a convergence state. In this way, the local carrier frequency and the carrier frequency of the navigation signal are kept synchronized, thereby improving the accuracy of data collection. For example, in the first navigation time slot (0th to 20th milliseconds), the feedback correction loop reaches a convergence state at the 10th millisecond, then the local carrier frequency corresponding to the 10th millisecond, the local carrier frequency corresponding to the 11th millisecond, ..., and the local carrier frequency corresponding to the 20th millisecond can be collected in the first navigation time slot. In the second navigation time slot (80th to 100th milliseconds), the feedback correction loop reaches a convergence state at the 15th millisecond, then the local carrier frequency corresponding to the 95th millisecond, the local carrier frequency corresponding to the 96th millisecond, ..., and the local carrier frequency corresponding to the 100th millisecond can be collected in the second navigation time slot. And so on.

[0050] Furthermore, the corresponding relationship between the local carrier frequency and the time point in at least one historical navigation time slot adjacent to the target navigation time slot can be obtained to construct an estimation model. Since the adjacent historical navigation time slots are relatively close to the target navigation time slot, the motion state of the satellite in these historical navigation time slots can be relatively similar to the motion state of the satellite in the target navigation time slot. In this way, the estimation model constructed based on the corresponding relationship between the local carrier frequency and the time point in these historical navigation time slots can more accurately reflect the current motion state of the satellite, thereby ensuring the accuracy of the estimation result.

[0051] In some embodiments, the construction of the estimation model based on the correspondence between the local carrier frequency and the time point in at least one navigation time slot before the target navigation time slot may include: A quadratic change curve model is constructed, wherein the quadratic change curve model includes model coefficients to be solved, and the independent variable of the quadratic change curve model is the time point, and the dependent variable is the local carrier frequency; Based on the corresponding relationship between the local carrier frequency and the time point, the value of the model coefficient is determined, and the value of the model coefficient is substituted into the quadratic change curve model to obtain the estimation model.

[0052] Specifically, the quadratic change curve model can be expressed as expression (1): (1) Among them, a, b, and c are the model coefficients to be solved. is the i-th time point, is the local carrier frequency corresponding to the i-th time point, the value range of i is 1 to n, and n is the total number of time points.

[0053] The corresponding relationship between the local carrier frequency and the time point in at least one navigation time slot before the target navigation time slot is input into expression (1), and the model residual as shown in expression (2) can be calculated. and the residual statistic as shown in expression (3) : (2) (3) Based on the residual statistics , taking partial derivatives of the model coefficients a, b, and c, we can obtain the equations shown in expressions (4) to (6): (4) (5) (6) By solving equations (4) to (6), we can obtain the values ​​of the model coefficients as shown in expressions (7) to (9): (7) (8) (9) Substituting the values ​​of the model coefficients into the quadratic change curve model, the estimated model can be obtained.

[0054] In summary, after obtaining the tracking signal of the navigation signal, Doppler data can be extracted from the tracking signal, and navigation positioning can be performed based on the extracted Doppler data.

[0055] In order to improve the navigation positioning accuracy, the present disclosure also provides a navigation positioning method. The navigation positioning method can be applied to a navigation device. Figure 8 , which is a flow chart of a navigation and positioning method provided in one embodiment of the present disclosure. Figure 8 In the navigation positioning method, the following steps are included: Step S801: extracting Doppler data for navigation and positioning from the tracking signal of the navigation signal. The tracking signal is based on Figure 5 obtained by the method shown.

[0056] In this embodiment, time-sharing Doppler positioning can be performed. In this positioning method, Doppler data in multiple navigation time slots can be obtained for time-sharing positioning. The so-called time-sharing Doppler positioning is relative to multi-satellite Doppler positioning. In multi-satellite Doppler positioning, sufficient Doppler data can be obtained from multiple satellites at the same time for positioning, while in single-satellite Doppler positioning, the amount of data obtained in a single navigation time slot is not enough. Therefore, Doppler data in multiple navigation time slots are required for time-sharing positioning (i.e., time-sharing Doppler positioning).

[0057] In some embodiments, for a navigation signal received in any navigation time slot, Doppler data at multiple time points can be extracted from the tracking signal of the navigation signal, and the Doppler data at multiple time points can be averaged and counted, and the statistical results can be used as the Doppler data extracted from the navigation time slot. For example, in the first navigation time slot (0-20 milliseconds), assuming that the feedback correction loop reaches a convergence state at the 10th millisecond, the Doppler data at the 12th millisecond, 14th millisecond, 16th millisecond, and 18th millisecond can be averaged and counted, and the averaged statistical results can be used as the Doppler data of the first navigation time slot. By averaging statistics, the noise impact of the tracking loop can be reduced.

[0058] Step S802: Divide the designated ground into a plurality of grids, and determine the theoretical signal Doppler value at each grid based on the grid center position of each grid and the velocity position of the satellite.

[0059] Specifically, the relative position between each grid center and the satellite can be determined based on the grid center position of the grid and the instantaneous position of the satellite, and the speed of the grid center is regarded as 0, and the relative speed between each grid center and the satellite is determined based on the instantaneous speed of the satellite and the speed of the grid center. Then, the relative position and relative speed obtained by the solution can be substituted into the Doppler formula to obtain the theoretical signal Doppler value at each grid.

[0060] Step S803: according to the actual signal Doppler value at each grid, find the target grid where the difference between the theoretical signal Doppler value and the actual signal Doppler value is the smallest.

[0061] Specifically, the actual signal Doppler value may be a signal Doppler value actually detected at each grid (ie, a Doppler value extracted from the tracking signal).

[0062] By using the grid traversal method, the target grid can be found.

[0063] Step S803: construct a least squares iterative model based on the Doppler data, and use the position of the target grid as the initial position value to iteratively solve the least squares iterative model to obtain navigation positioning information.

[0064] Specifically, when performing iterative solutions based on the least squares iterative model, the initial position value and the observed wild value are usually more sensitive, thus affecting the solution results. In view of this, the present disclosure uses the position of the target grid where the difference between the theoretical signal Doppler value and the actual signal Doppler value is the smallest as the initial value to solve the least squares iterative model, which can improve the accuracy of the initial position value and reduce the impact of the initial position value on the solution results. At the same time, the Huber robust kernel function is introduced into the least squares iterative model, and weight distribution is performed based on the Huber robust kernel function, which can reduce the impact of the observed wild value on the solution results.

[0065] Based on the above description, in this embodiment, the least squares iterative model can be shown as expressions (10) to (11): (10) (11) in, is the Huber robust weighting function, is the normalized residual, is the unnormalized residual, is the error, is the navigation positioning information of the kth iteration, is the navigation positioning information of the k-1th iteration, G is the coefficient matrix, is the transposed matrix of the coefficient matrix G.

[0066] In expressions (10) to (11), after each iteration, if If it is greater than the preset threshold, it means that the least squares iterative model has not converged and X can be updated and iterated again; If it is less than the preset threshold, it means that the least squares iterative model has converged, and X is the final navigation positioning information.

[0067] In summary, in some embodiments of the present disclosure, navigation positioning can be performed based on the following process: 1) Receive signals sent by satellite using time division multiplexing communication method.

[0068] 2) When receiving the navigation signal, perform one of the following steps 21) to 22): 21) If the current time slot is the first navigation time slot, the continuous wave at the front end position of the navigation signal is captured, and based on the continuous wave, an estimated value of the local carrier frequency is determined; and based on the estimated value of the local carrier frequency, a local oscillator is controlled; and after the local oscillator is controlled, the acquired navigation signal is input into a feedback correction loop.

[0069] 22) If the current time slot is not the first navigation time slot, the acquired navigation signal is directly input into the feedback correction loop.

[0070] 3) Use the pseudo code ranging information in the navigation signal to achieve high-precision synchronization of the code phase and provide initial code phase information for continuous tracking of subsequent signals.

[0071] 4) Extracting Doppler data from the tracking signal of the navigation signal; 5) When a non-navigation signal is received (i.e., entering a non-navigation time slot), the carrier frequency of the next target navigation signal is estimated, and the local oscillator is controlled based on the estimated value; 6) After accumulating the Doppler data of multiple navigation time slots, the least squares iterative model in expressions (10) and (11) is iteratively solved to obtain the navigation positioning information.

[0072] In some embodiments, after obtaining the navigation positioning information, the clock difference between the navigation device and the satellite can be estimated based on the navigation positioning information and the pseudo-code ranging information in the navigation signal, and the timing of the navigation device can be completed based on the estimation result and the time information in the navigation signal.

[0073] Corresponding to the method for tracking a navigation signal from a fused signal, the present disclosure also provides a device for tracking a navigation signal from a fused signal. Fig. 9 , is a module diagram of an apparatus for tracking navigation signals from fused signals provided by an embodiment of the present disclosure. Fig. 9 The devices include: A feedback correction module 91 is used for inputting the navigation signal into a feedback correction loop in response to receiving the navigation signal, and the feedback correction loop adjusts the local carrier frequency output by the local oscillator based on the carrier frequency of the navigation signal to obtain a tracking signal of the navigation signal; The output correction module 92 is used to estimate the carrier frequency of the target navigation signal after the non-navigation signal in response to receiving the non-navigation signal, and use the estimation result as the initial local carrier frequency output by the local oscillator when tracking the target navigation signal.

[0074] In some embodiments, the output correction module 92 is specifically used to: If the target navigation signal is a navigation signal received in the first navigation time slot, capturing a continuous wave at a specified position in the target navigation signal; The captured continuous wave is subjected to discrete Fourier transform to obtain an estimate of the carrier frequency of the target navigation signal.

[0075] In some embodiments, the output correction module 92 is specifically used to: If the target navigation signal is a navigation signal received in a target navigation time slot other than the first navigation time slot, constructing an estimation model based on a correspondence between a local carrier frequency and a time point in at least one navigation time slot before the target navigation time slot; The starting time point of the target navigation time slot is input into the estimation model, and the estimation model outputs the estimated value of the carrier frequency of the target navigation signal.

[0076] In some embodiments, the output correction module 92 is specifically used to obtain the corresponding relationship between the local carrier frequency and the time point based on the following method: In any navigation time slot, when the feedback correction loop reaches a convergence state, the corresponding relationship between the local carrier frequency and the time point is triggered to be collected.

[0077] In some embodiments, the output correction module 92 is specifically used to: A quadratic change curve model is constructed, wherein the quadratic change curve model includes model coefficients to be solved, and the independent variable of the quadratic change curve model is the time point, and the dependent variable is the local carrier frequency; Based on the corresponding relationship between the local carrier frequency and the time point, the value of the model coefficient is determined, and the value of the model coefficient is substituted into the quadratic change curve model to obtain the estimation model.

[0078] Corresponding to the navigation and positioning method, the present disclosure also provides a navigation and positioning device. Fig.10 , which is a module diagram of a navigation and positioning device provided in one embodiment of the present disclosure. Fig.10 The devices include: The data extraction module 101 is used to extract Doppler data for navigation positioning from the tracking signal of the navigation signal. The tracking signal is based on Figure 5 The method shown is obtained; A grid division module 102 is used to divide the designated ground into a plurality of grids, and determine a theoretical signal Doppler value at each grid based on the grid center position of each grid and the velocity position of the satellite; A grid search module 103 is used to search for a target grid having the smallest difference between a theoretical signal Doppler value and an actual signal Doppler value according to the actual signal Doppler value at each grid; The model building module 104 is used to build a least squares iterative model based on the Doppler data, and solve the least squares iterative model using the position of the target grid as an initial value to obtain navigation positioning information.

[0079] In some embodiments, the model building module 104 is specifically used to build the following least squares iterative model:

[0080]

[0081] in, is the Huber robust weighting function, is the normalized residual, is the unnormalized residual, is the error, is the navigation positioning information of the kth iteration, is the navigation positioning information of the k-1th iteration, G is the coefficient matrix, is the transposed matrix of the coefficient matrix G.

[0082] In some embodiments, the data extraction module 101 is specifically used to: For a navigation signal received in any navigation time slot, Doppler data at multiple time points are extracted from the tracking signal of the navigation signal, and the Doppler data at multiple time points are averaged and counted, and the statistical result is used as the Doppler data extracted in the navigation time slot.

[0083] The device for tracking the navigation signal from the fusion signal in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0084] The device for tracking a navigation signal from a fused signal disclosed in the present invention has the same beneficial effects as the method for tracking a navigation signal from a fused signal described above, which will not be described in detail herein.

[0085] The present disclosure also provides an electronic device having the above Fig. 9 The device for tracking the navigation signal from the fused signal as shown, or Fig.10 The navigation and positioning device shown.

[0086] Combined with reference Fig.11 , is a schematic diagram of the structure of an electronic device provided by some embodiments of the present disclosure. Fig.11As shown, the electronic device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process instructions executed in the electronic device, including instructions stored in or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple electronic devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.11 A processor 10 is taken as an example.

[0087] The processor 10 may be a first PCIe device, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0088] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0089] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the electronic device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0090] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0091] The electronic device further comprises a communication interface 30 for the electronic device to communicate with other devices or a communication network.

[0092] The embodiments of the present disclosure also provide a computer-readable storage medium. The above-mentioned method according to the embodiments of the present disclosure can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium and downloaded through a network, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0093] A part of the present disclosure may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present disclosure through the operation of the computer. Those skilled in the art should understand that the existence of computer program instructions in computer-readable media includes, but is not limited to, source files, executable files, installation package files, etc., and accordingly, the way in which computer program instructions are executed by a computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to the computer.

[0094] Although the embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for tracking a navigation signal from a fused signal, characterized in that: The fused signal includes a navigation signal sent by the satellite in a navigation time slot and a non-navigation signal sent in a non-navigation time slot, and the method includes: In response to receiving the navigation signal, inputting the navigation signal into a feedback correction loop, wherein the feedback correction loop adjusts a local carrier frequency output by a local oscillator based on the carrier frequency of the navigation signal to obtain a tracking signal of the navigation signal; In response to receiving the non-navigation signal, a carrier frequency of a target navigation signal following the non-navigation signal is estimated, and the estimation result is used as an initial local carrier frequency output by the local oscillator when tracking the target navigation signal.

2. The method according to claim 1, characterized in that The estimating the carrier frequency of the target navigation signal following the non-navigation signal comprises: If the target navigation signal is a navigation signal received in the first navigation time slot, capturing a continuous wave at a specified position in the target navigation signal; The captured continuous wave is subjected to discrete Fourier transform to obtain an estimated value of the carrier frequency of the target navigation signal.

3. The method according to claim 1 or 2, characterized in that: The estimating the carrier frequency of the target navigation signal following the non-navigation signal comprises: If the target navigation signal is a navigation signal received in other target navigation time slots other than the first navigation time slot, constructing an estimation model based on a correspondence between a local carrier frequency and a time point in at least one navigation time slot before the target navigation time slot; The starting time point of the target navigation time slot is input into the estimation model, and the estimation model outputs an estimated value of the carrier frequency of the target navigation signal.

4. The method according to claim 3, characterized in that The correspondence between the local carrier frequency and the time point is obtained based on the following method: In any of the navigation time slots, when the feedback correction loop reaches a convergence state, the acquisition of the correspondence between the local carrier frequency and the time point is triggered.

5. The method according to claim 3, characterized in that: The constructing the estimation model based on the correspondence between the local carrier frequency and the time point in at least one navigation time slot before the target navigation time slot includes: Constructing a quadratic change curve model, wherein the quadratic change curve model includes model coefficients to be solved, and the independent variable of the quadratic change curve model is the time point, and the dependent variable is the local carrier frequency; Based on the correspondence between the local carrier frequency and the time point, the value of the model coefficient is determined, and the value of the model coefficient is substituted into the quadratic change curve model to obtain the estimation model.

6. A navigation positioning method, characterized in that: The method comprises: Extracting Doppler data for navigation positioning from a tracking signal of a navigation signal, wherein the tracking signal is obtained based on the method according to any one of claims 1 to 5; Divide the designated ground into a plurality of grids, and determine a theoretical signal Doppler value at each grid based on a grid center position of each grid and a velocity position of a satellite; According to the actual signal Doppler value at each grid, find the target grid with the smallest difference between the theoretical signal Doppler value and the actual signal Doppler value; Based on the Doppler data, a least squares iterative model is constructed, and the position of the target grid is used as an initial position value to solve the least squares iterative model to obtain navigation positioning information.

7. The method according to claim 6, characterized in that The least squares iterative model is the following model: in, is the Huber robust weighting function, is the normalized residual, is the unnormalized residual, is the error, is the navigation positioning information of the kth iteration, is the navigation positioning information of the k-1th iteration, G is the coefficient matrix, is the transposed matrix of the coefficient matrix G.

8. The method according to claim 6, characterized in that The step of extracting Doppler data for navigation and positioning from the tracking signal of the navigation signal comprises: For the navigation signal received in any of the navigation time slots, Doppler data at multiple time points are extracted from the tracking signal of the navigation signal, and the Doppler data at the multiple time points are averaged and counted, and the statistical result is used as the Doppler data extracted in the navigation time slot.

9. A device for tracking a navigation signal from a fused signal, characterized in that: The fused signal includes a navigation signal sent by the satellite in a navigation time slot and a non-navigation signal sent in a non-navigation time slot, and the device includes: a feedback correction module, configured to input the navigation signal into a feedback correction loop in response to receiving the navigation signal, and adjust the local carrier frequency output by the local oscillator based on the carrier frequency of the navigation signal by the feedback correction loop to obtain a tracking signal of the navigation signal; The output correction module is used for estimating the carrier frequency of the target navigation signal after the non-navigation signal in response to receiving the non-navigation signal, and using the estimation result as the initial local carrier frequency output by the local oscillator when tracking the target navigation signal.

10. A navigation and positioning device, characterized in that: The device comprises: A data extraction module, used to extract Doppler data for navigation positioning from a tracking signal of a navigation signal, wherein the tracking signal is obtained based on the method according to any one of claims 1 to 5; A grid division module, used for dividing the designated ground into a plurality of grids, and determining a theoretical signal Doppler value at each grid based on the grid center position of each grid and the velocity position of the satellite; A grid search module is used to search for a target grid having the smallest difference between a theoretical signal Doppler value and an actual signal Doppler value according to the actual signal Doppler value at each grid; The model building module is used to build a least squares iterative model based on the Doppler data, and use the position of the target grid as the initial position value to solve the least squares iterative model to obtain navigation positioning information.

11. An electronic device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, wherein the memory stores computer instructions, and wherein the processor executes the method for tracking a navigation signal from a fused signal as described in any one of claims 1 to 5, or executes the navigation positioning method as described in any one of claims 6 to 8 by executing the computer instructions.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method for tracking a navigation signal from a fused signal according to any one of claims 1 to 5, or to execute the navigation positioning method according to any one of claims 6 to 8.

Images