Method for tracking GNSS signals with a regulation loop only for phase regulation and a regulation loop

Abstract

The invention relates to a method for tracking GNSS signals by means of a GNSS receiver having a plurality of channels, at least one channel comprising a generator (9), a phase-based filter (6) and a frequency-based filter (7), such that the generator (9) forms a first control loop with the phase-based filter (6) and a second control loop with the frequency-based filter (7), the generator (9) can be adjusted in an epoch manner by means of two adjustment loops for generating a local replica (10) and updating the replica (10), and wherein the GNSS signal (3) is tracked on at least one channel by means of the following steps: a) generating the local replica (10) by means of the generator (9), b) a first control variable (11) in the form of a phase is generated exclusively by means of the phase-based filter (6) of the first control loop, c) a second control variable (12) in the form of a Doppler frequency is generated exclusively by means of the frequency-based filter (7) of the second control loop, d) updating the replica (10) while adjusting the generator (9) directly with the first adjustment variable (11) and the second adjustment variable (12) or at least with a corrected second adjustment variable which has been corrected taking into account the first adjustment variable (11), and e) repeating steps b) to d) in order to update the replica (10) epochwise.

Description

Field of the Invention

[0001] The present invention relates to a method for tracking GNSS signals using an adjustment loop for phase adjustment only and an adjustment loop for Doppler frequency adjustment only. In addition, a GNSS receiver, a control unit, a computer program, and a machine-readable storage medium are also described. The present invention can be used in particular for GNSS-supported positioning systems for autonomous or semi-autonomous driving. Background Art

[0002] Currently, there are multiple vector tracking (VT) methods for tracking GNSS satellites, which are developed based on known scalar tracking (ST) methods to improve tracking capabilities. Vector tracking methods can be divided into three main categories, namely frequency-based vector frequency locked loop (VFLL), code-based vector delay locked loop (VDLL), and phase-based vector phase locked loop (VPLL). Using a (virtual) base station as a reference unit, vector tracking methods including, for example, differential vector phase locked loop (DVPLL) can be extended.

[0003] GNSS signals are in principle carriers with codes. Therefore, signal tracking has two main tasks, namely code control and carrier control. Code control is usually performed using a code-based locked loop (such as DLL or VDLL), and carrier control is performed using a phase-based locked loop (such as PLL, VPLL, or DVPLL) and / or a frequency-based locked loop (such as FLL or VFLL).

[0004] For carrier control, compared with frequency-based locked loops, phase-based locked loops generally have higher accuracy but lower robustness. Therefore, in known embodiments (such as a PLL tracking loop supported by FLL (F-PLL)), a frequency-based locked loop supports a phase-based locked loop, such that the two locked loops are alternately activated, for example, in such a way that the frequency-based locked loop is activated for Doppler frequency adjustment to more quickly detect the GNSS signal to be tracked, and subsequently the phase-based locked loop is activated for phase and Doppler frequency adjustment to more accurately track the detected GNSS signal. However, the alternate activation of the two locked loops results in changes in filters and / or parameters during control and regulation operation, and thus results in interference that deteriorates the stability of signal tracking. Therefore, it is desirable to cancel the alternate activation of the two locked loops in order to generally improve the reliability and robustness of the signal tracking system. Summary of the Invention

[0005] Starting from this, the object of the present invention is to alleviate or at least partially solve the problems described with respect to the prior art. In particular, a method for tracking GNSS signals using an adjustment loop solely for phase adjustment and an adjustment loop solely for Doppler frequency adjustment should be described, which enables phase adjustment and Doppler frequency adjustment to be carried out using their respective adjustment loops without alternating activation but with simultaneous activation, so that phase adjustment and Doppler frequency adjustment can support and improve each other, thereby improving the accuracy, robustness and stability of signal tracking, and thus improving the overall tracking performance.

[0006] A method for tracking GNSS signals with the aid of a GNSS receiver having a plurality of channels contributes to this, wherein at least one channel comprises a generator, a phase-based filter and a frequency-based filter, such that the generator forms a first adjustment loop with the phase-based filter and a second adjustment loop with the frequency-based filter, so that the generator can be adjusted epoch by epoch using the two adjustment loops for generating a local replica and updating the replica, and wherein, on at least one channel, the GNSS signal is tracked using the following steps:

[0007] a) Generating a local replica using the generator,

[0008] b) Detecting a first adjustment parameter in the form of a phase only using the phase-based filter of the first adjustment loop,

[0009] c) Detecting a second adjustment parameter in the form of a Doppler frequency only using the frequency-based filter of the second adjustment loop,

[0010] d) Updating the replica in the case of adjusting the generator either directly using the first adjustment parameter and the second adjustment parameter or at least using the corrected second adjustment parameter corrected taking into account the first adjustment parameter, and

[0011] e) Repeating steps b) to d) in order to update the replica epoch by epoch.

[0012] The vehicle can be navigated in the following way using the method described herein, namely by calculating a navigation solution, such as a classical position velocity time (PVT) prediction for single point positioning (SPP), using the tracked GNSS signal. The method described is particularly suitable for autonomous driving. Autonomous driving is understood here as the forward movement of vehicles that operate largely autonomously with the aid of a GNSS receiver and based on the Global Navigation Satellite System (GNSS). The vehicle can be a motor vehicle, such as a passenger car, truck or other commercial vehicle, a robot, etc. Particularly advantageously, the vehicle is equipped with a GNSS receiver using which the method described is carried out and the vehicle is navigated.

[0013] The GNSS receiver described herein may have multiple channels, so that multiple GNSS signals can be tracked simultaneously on multiple channels, where each GNSS signal is tracked on a single channel. It can be set that steps a) to d) are performed simultaneously on multiple channels, so that multiple GNSS signals can be tracked simultaneously in order to calculate a navigation solution.

[0014] A GNSS signal is in principle a high-frequency carrier and a low-frequency code modulated thereon. Thus, a channel is a signal processing unit configured for carrier and code control such that, when controlling the carrier, the phase and frequency of the carrier of the GNSS signal are tracked, and when controlling the code, the code modulated onto the carrier is regained.

[0015] Since the phase of the carrier of a GNSS signal may change due to the time shift between transmission and reception, and the frequency of the carrier may change due to the Doppler effect, phase adjustment and Doppler frequency adjustment are particularly performed when controlling the carrier. For this purpose, a generator is used to generate a local copy, the phase and frequency of which track the phase and frequency of the carrier of the GNSS signal to be tracked, such that the phase and frequency of the copy are always in a specific ratio to the phase and frequency of the carrier, and thus tracking of the GNSS signal can be achieved.

[0016] The generator is in particular an NCO (NCO: numerically controlled oscillator), which can be adjusted epoch by epoch via at least one adjustment parameter using at least one closed adjustment loop, so that the phase and frequency of the copy generated by the generator can be updated epoch by epoch, such that the phase and frequency of the copy are always in a specific ratio to the phase and frequency of the received carrier. Phase and Doppler frequency adjustment herein involves the adjustment of the epochs of the generator to generate a copy with adjusted phase and frequency.

[0017] It can be set that at least one channel is configured such that the channel includes a first adjustment loop and a second adjustment loop, so that the first adjustment loop can be used only for phase adjustment and the second adjustment loop can be used only for Doppler frequency adjustment. The first adjustment loop and the second adjustment loop are connected in parallel to each other and are always activated or deactivated simultaneously. Thus, a switch for alternately activating the two adjustment loops is no longer required.

[0018] It can be set that the first adjustment loop includes at least one phase-based filter, which generates a first adjustment parameter, for example, in epoch n

[0019] The first adjustment parameter is used to correct the phase of the replica in epoch n+1. The correction is generated by the phase residual between the NCO phase in epoch n and the adjustment parameter in epoch n, where n is a natural number. Equivalently, alternatively, the first adjustment parameter can be directly used in epoch n in order to also update the phase of the generator in epoch n. Additionally, the first adjustment loop can include a phase-based correlator and a phase-based discriminator. Thus, the first adjustment loop is formed at least by the phase-based correlator, the phase-based discriminator, the phase-based filter, and the generator.

[0020] It can be set that the second adjustment loop includes at least one frequency-based filter, which generates a second adjustment parameter, for example, in epoch n. The second adjustment parameter can be the currently determined Doppler frequency, by means of which, in epoch n+1, only the frequency of the replica is updated or the frequency and phase of the replica are updated, where n is a natural number. Additionally, the second adjustment loop can include a frequency-based correlator and a frequency-based discriminator. Thus, the second adjustment loop is formed at least by the frequency-based correlator, the frequency-based discriminator, the frequency-based filter, and the generator.

[0021] It can be set that the phase-based correlator and the frequency-based correlator are configured to form a common signal processing device, and the phase-based discriminator and the frequency-based discriminator are configured to form a common discrimination device. Thus, the first adjustment loop is formed by the signal processing device, the discrimination device, the phase-based filter, and the generator, while the second adjustment loop is formed by the signal processing device, the discrimination device, the frequency-based filter, and the generator.

[0022] When the GNSS signal arrives at the channel, a local replica is generated using the generator according to step a). Subsequently, steps b) to d) are repeated epoch by epoch in order to update the phase and frequency of the replica epoch by epoch and thus track the phase and frequency of the carrier of the GNSS signal. In one epoch, the phase and frequency of the replica are updated once. The epoch is represented by the natural number n, where n is the current epoch, n-1 is the previous epoch, and n+1 is the subsequent epoch.

[0023] According to step b), the first adjustment parameter in the form of a phase is detected only by the phase-based filter of the first adjustment loop. The phase detected by the phase-based filter is denoted herein as PHI_n, where n is the epoch number. The phase PHI_n detected by the phase-based filter in epoch n can adjust the phase of the copy to be updated as an adjustment parameter. In epoch n, PHI_n is detected only by the first adjustment loop, for example, by correlating the copy in epoch n with the GNSS signal in epoch n using a phase-based correlator, determining the phase deviation between the copy in epoch n and the GNSS signal in epoch n using a phase-based discriminator, and detecting PHI_n based on a specific phase deviation using a phase-based filter.

[0024] According to step c), the second adjustment parameter in the form of a Doppler frequency is detected only by the frequency-based filter of the second adjustment loop. The Doppler frequency detected by the frequency-based filter is denoted herein as fd_n, where n is the epoch number. The fd_n detected by the frequency-based filter in epoch n can adjust only the frequency or both the frequency and the phase of the copy to be updated in epoch n + 1 as an adjustment parameter. In epoch n, fd_n is generated only by the second adjustment loop, for example, by correlating the copy in epoch n with the GNSS signal in epoch n using a frequency-based correlator, determining the frequency deviation between the copy in epoch n and the GNSS signal in epoch n using a frequency-based discriminator, and generating fd_n based on a specific frequency deviation using a frequency-based filter.

[0025] In principle, step b) and step c) are executed in parallel and simultaneously, such that the first adjustment loop and the second adjustment loop are both active at the same time.

[0026] According to step d), the copy is updated in the case of either directly using the first and second adjustment parameters or at least using the corrected second adjustment parameter that has been corrected at least taking into account the first adjustment parameter to adjust the generator. That is to say, according to the application scenario, there are at least two possibilities for adjusting the generator.

[0027] According to one possibility, the first and second adjustment parameters are directly used to adjust the generator without correction. This means that PHI_n detected only by the first adjustment loop in step b) and fd_n detected only by the second adjustment loop in step c) are directly input into the generator without correction. This is particularly advantageous for reducing the computational cost, for example, if the GNSS signal to be tracked can be received outdoors, for example, on a highway, with a good carrier-to-noise ratio, because in such an application scenario, PHI_n and fd_n can be matched well enough.

[0028] According to a further possibility, the second adjustment parameter is corrected at least taking into account the first adjustment parameter, and the at least corrected second adjustment parameter is used to adjust the generator. This is particularly advantageous for accurate and robust signal tracking, for example if the GNSS signal to be tracked is received in an urban environment with a poor carrier-to-noise ratio and / or multipath effects. In such an application scenario, PHI_n and fd_n can no longer be matched well enough so that PHI_n and fd_n cannot be directly input into the generator. The correction of PHI_n and / or fd_n is advantageous. In principle, PHI_n and fd_n can be corrected with respect to each other, for example, in such a way that PHI_n is corrected using fd_n integrated over the time difference dT between two epochs (i.e., by integral calculation), and fd_n is corrected using the deviation of PHI_n from the phase updated in epoch n + 1 of the replica differentiated over the time difference dT (i.e., by differential calculation).

[0029] In order to determine the at least corrected second adjustment parameter, the following sub-steps can be performed:

[0030] i) Determine the phase of the replica in epoch n, which is represented by Phi_n and can be read directly from the generator;

[0031] ii) Detect the phase PHI_n in epoch n using the phase-based filter of the first adjustment loop and detect the Doppler frequency fd_n in epoch n using the frequency-based filter of the second adjustment loop, where PHI_n is the first adjustment parameter and fd_n is the second adjustment parameter;

[0032] iii) Calculate the phase residual according to the formula dPHI = Phi_n + fd_n * dT - PHI_n+1 by comparing PHI_n+1 with the sum of PHi_n and fd_n integrated over the time difference, where dPHI is the phase residual, dT is the time difference between epoch n and epoch n + 1, and PHI_n+1 is the phase detected using the phase-based filter of the first adjustment loop in epoch n + 1;

[0033] iv) Calculate the at least corrected second adjustment parameter in epoch n + 1 according to the formula F_n+1 = fd_n+1 + dPHI / dT, where fd_n+1 is the Doppler frequency detected using the frequency-based filter of the second adjustment loop in epoch n + 1, and F_n+1 is the at least corrected second adjustment parameter in epoch n + 1, and where the at least corrected second adjustment parameter is essentially the Doppler frequency filtered using the first interference parameter, i.e., the phase estimate, and

[0034] v) Adjust the generator to generate a replica in epoch n+2 using the corrected second adjustment parameter F_n+1, where the phase residual dPHI can also be compensated within dT.

[0035] Different from known methods in which the carrier is adjusted by a single adjustment loop (such as a PLL or FLL) or by two adjustment loops that are alternately activated in time (such as an F-PLL), in the method described herein, the carrier is adjusted by two simultaneously activated adjustment loops, so that one adjustment loop is only used for phase adjustment and the other adjustment loop is only used for Doppler frequency adjustment. This has the particular advantage that the phase and Doppler frequency adjustments can support and improve each other, thereby improving the accuracy and robustness of signal tracking. In the method described herein, instead of alternately activating between two adjustment loops, the two adjustment loops are always simultaneously activated, thereby also improving the stability of signal tracking.

[0036] Preferably, before step d), the phase residual between the last updated phase of the replica and the currently detected first adjustment parameter is additionally calculated taking into account the last detected second adjustment parameter. The phase residual can be calculated using the method described in sub-step iii).

[0037] Preferably, the second adjustment parameter is corrected using the phase residual. The second adjustment parameter can be corrected using the method described in sub-step iv).

[0038] Preferably, a threshold for the phase residual is preset. The threshold is, for example, a fixed preset parameter that represents the maximum correction of the generator phase and is referred to herein as PHI_Korr_max. By comparing the threshold with the phase residual, it can be determined whether to directly use the first and second adjustment parameters or at least the corrected second adjustment parameter to adjust the generator in step d).

[0039] Preferably, in step d), if the phase residual is less than or equal to the threshold, then the replica is updated in the case of directly using the first and second adjustment parameters to adjust the generator.

[0040] Additionally preferably, in step d), if the phase residual is greater than the threshold, then the replica is updated in the case of at least using the corrected second adjustment parameter to adjust the generator.

[0041] By comparing the phase residual dPHI calculated in sub-step iii) with the preset threshold PHI_Korr_max, the following sub-steps can be performed in step d) according to the comparison result:

[0042] - If dPHI <= PHI_Korr_max, then the PHI_n detected in sub-step ii) is used for the phase adjustment of the generator, and the fd_n detected in sub-step ii) is used for the Doppler frequency adjustment of the generator, i.e., the generator directly uses the first

[0043] and second adjustment parameters to perform the adjustment without correction;

[0044] - If dPHI > PHI_Korr_max, then instead of PHI_n determined in sub-step ii), the threshold value PHI_Korr_max is used for the phase adjustment of the generator, and F_n+1 calculated according to the formula F_n+1 = fd_n+1 + dPHI2 / dT is used for the Doppler frequency adjustment of the generator, where dPHI2 corresponds to the difference between dPHI and PHI_Korr_max. In this case, the generator basically uses the corrected first adjustment parameter and the corrected second adjustment parameter for the adjustment.

[0045] Furthermore, a GNSS receiver is proposed, which includes a plurality of channels designed to track GNSS signals, wherein at least one channel includes a generator, a phase-based filter, and a frequency-based filter, such that the generator forms a first adjustment loop using the phase-based filter and a second adjustment loop using the frequency-based filter, wherein the first adjustment loop is designed to adjust the generator only using the first adjustment parameter in the form of phase, and wherein the second adjustment loop is designed to adjust the generator only using the second adjustment parameter in the form of Doppler frequency.

[0046] Preferably, the first adjustment loop and the second adjustment loop are connected in parallel to each other and are simultaneously activated when tracking GNSS signals.

[0047] Preferably, the first adjustment loop is a scalar phase-locked loop or a vector phase-locked loop or a differential vector phase-locked loop.

[0048] Preferably, the second adjustment loop is a scalar frequency-locked loop or a vector frequency-locked loop.

[0049] Preferably, the generator can be adjusted by phase and Doppler frequency or only by Doppler frequency.

[0050] Preferably, the control unit for the GNSS receiver is designed to execute the described method.

[0051] Furthermore preferably, a computer program is used to execute the method described herein. In other words, this particularly relates to a computer program (product) that includes instructions which, when the program is executed by a computer, cause the computer to execute the method described herein.

[0052] Furthermore, it is preferred to use a machine-readable storage medium on which the computer program presented here is stored. Generally, a machine-readable storage medium is a computer-readable data carrier. Description of the Drawings

[0053] The solution presented here and its technical environment are subsequently explained in detail with the aid of the drawings. It should be noted that the invention is not limited to the embodiments shown. In particular, unless otherwise explicitly stated, partial aspects of the facts explained in the drawings can also be extracted and combined with other drawings and / or other components of this description and / or findings. Schematically and by way of example:

[0054] Figure 1 shows a conventional FLL-supported PLL regulation loop, and

[0055] Figure 2 shows the proposed FLL-supported PLL regulation loop. Detailed Description of the Invention

[0056] Figure 1 shows a simplified diagram of a conventional FLL-supported PLL regulation loop 1 for phase and Doppler regulation of a generator 9 to generate a local copy 10 of an input GNSS signal 3.

[0057] By means of a switch 8, the phase regulation loop or the frequency regulation loop is alternately formed and activated, where the phase regulation loop is formed by a signal processing device 4, a discrimination device 5, a phase-based filter 6 and a generator 9, and the frequency regulation loop is formed by a signal processing device 4, a discrimination device 5, a frequency-based filter 7 and a generator 9. In this way, the generator 9 can be regulated either only with the regulation parameters determined by the phase-based filter 6 or only with the regulation parameters determined by the frequency-based filter 7 (see the dashed line in switch 8). This has the disadvantage that the alternating activation of the two regulation loops leads to filtering and / or parameter changes during the regulation operation and thus to interference that deteriorates the stability of signal tracking. Another disadvantage is that the regulation parameters determined with the phase-based filter 6 and with the frequency-based filter 7 cannot correct each other.

[0058] In contrast to Figure 1 the conventional FLL-supported PLL regulation loop 1 shown, in Figure 2The FLL-supported PLL control loop 2 proposed in the specification also consists of a phase control loop and a frequency control loop. The phase control loop is formed by a signal processing device 4, an identification device 5, a phase-based filter 6 and a generator 9; the frequency control loop is formed by a signal processing device 4, an identification device 5, a frequency-based filter 7 and a generator 9.

[0059] and Figure 1 The conventional PLL control loop 1 supported by FLL shown differs in that Figure 2 The PLL control loop 2 supported by the FLL proposed in does not have a switch. Therefore, the two control loops are always activated or deactivated at the same time. Thus, the stability of signal tracking can be improved because the alternating activation of the two control loops is cancelled. In addition, the generator 9 can be adjusted using the first control variable 11 determined by the phase-based filter 6 and the second control variable 12 determined by the frequency-based filter 7. The generator 9 can be adjusted directly using the first control variable 11 and the second control variable 12 in a good carrier-to-noise ratio, or in a poor carrier-to-noise ratio using the corrected first control variable and the corrected second control variable, wherein in particular, the first control variable 11 and the second control variable 12 can be corrected with each other. Thus, the accuracy and robustness of signal tracking can be improved.

[0060] Using the proposed PLL regulation loop 2 supported by the FLL, the GNSS signal 3 can be tracked in the following steps:

[0061] I) determine the phase of the replica in epoch n, which is denoted by Phi_n and can be read directly from the generator,

[0062] II) detecting a phase PHI_n in epoch n using a phase-based filter of a first control loop, and detecting a Doppler frequency fd_n in epoch n using a frequency-based filter of a second control loop, wherein PHI_n is a first control variable and fd_n is a second control variable,

[0063] III) calculating the phase residual according to the formula dPHI=Phi_n+fd_n*dT-PHI_n+1 by comparing PHI_n+1 with the sum of PHi_n and fd_n integrated over the time difference, where dPHI is the phase residual, dT is the time difference between epoch n and epoch n+1, and PHI_n+1 is the phase detected in epoch n+1 using the phase-based filter of the first regulation loop,

[0064] IV) comparing the phase residual dPHI calculated in sub-step III) with a preset threshold value PHI_Korr_max,

[0065] V) Perform the subsequent sub - steps:

[0066] 1) If dPHI <= PHI_Korr_max, then the PHI_n detected in sub - step II) is used for the phase adjustment of the generator, and the fd_n detected in sub - step II) is used for the Doppler frequency adjustment of the generator; or

[0067] 2) If dPHI > PHI_Korr_max, then instead of the PHI_n detected in sub - step II), the threshold PHI_Korr_max is used for the phase adjustment of the generator, and F_n + 1 calculated according to the formula F_n+1 = fd_n+1 + dPHI2 / dT is used for the Doppler frequency adjustment of the generator, where dPHI2 corresponds to the difference between dPHI and PHI_Korr_max, and where fd_n + 1 is the Doppler frequency detected in epoch n + 1 using the frequency - based filter of the second adjustment loop, and

[0068] VI) Adjust the generator for updating the replica (or the adjustment parameters of the generator in epoch n + 1) according to sub - step 1) or according to sub - step 2).

[0069] If the generator 9 can only be adjusted by the Doppler frequency, then the generator 9 can only be adjusted using the second adjustment parameter 12 or the corrected second adjustment parameter. In this case, the first adjustment parameter 11 can be fed into the measurement production engine to correct the phase measurement. This can be achieved by the parameter PHASE_OUT_CORR, which is added to the phase output value PHASE_OUT of the measurement production engine, where the phase output value PHASE_OUT can be detected by evaluating the internal state of the generator 9 according to the formula PHASE_OUT’ = PHASE_OUT+PHASE_OUT_CORR, and where PHASE_OUT’ is the corrected phase output value of the measurement production engine, and where PHASE_OUT_CORR can be detected as follows:

[0070] - If there is a good carrier - to - noise ratio and the generator is directly adjusted by the uncorrected second adjustment parameter 12, then PHASE_OUT_CORR = PHI - PHASE_OUT, or

[0071] - If dPHI <= PHI_Korr_max, then PHASE_OUT_CORR = dPHI, or

[0072] - If dPHI > PHI_Korr_max, then PHASE_OUT_CORR = PHI_Korr_max.

Claims

1. A method for tracking GNSS signals by means of a GNSS receiver having a plurality of channels, wherein, At least one channel includes a generator (9), a phase-based filter (6), and a frequency-based filter (7), such that the generator (9) forms a first adjustment loop using the phase-based filter (6) and a second adjustment loop using the frequency-based filter (7), so that the generator (9) can be adjusted epoch by epoch using the two adjustment loops for generating a local replica (10) and updating the replica (10), and wherein, on the at least one channel, the GNSS signal (3) is tracked using the following steps: a) Generate a local replica (10) using the generator (9), b) Detect a first adjustment parameter (11) in the form of a phase only using the phase-based filter (6) of the first adjustment loop, c) Detect a second adjustment parameter (12) in the form of a Doppler frequency only using the frequency-based filter (7) of the second adjustment loop, d) Update the replica (10) in the case of directly adjusting the generator (9) using the first adjustment parameter (11) and the second adjustment parameter (12) or at least using a corrected second adjustment parameter corrected in consideration of the first adjustment parameter (11), and e) Repeat steps b) to d) in order to update the replica (10) epoch by epoch.

2. The method according to claim 1, wherein, Before step d), a phase residual between the last updated phase of the replica and the currently detected first adjustment parameter (11) is additionally calculated in consideration of the last detected second adjustment parameter (12).

3. The method according to claim 2, wherein The second adjustment parameter (12) is corrected using the phase residual.

4. The method according to claim 2 or 3, wherein A threshold is preset for the phase residual.

5. The method according to claim 4, wherein In step d), if the phase residual is less than or equal to the threshold, then the replica is updated in the case of directly adjusting the generator using the first adjustment parameter (11) and the second adjustment parameter (12).

6. The method according to claim 4, wherein In step d), if the phase residual is greater than the threshold, then the replica is updated in the case of adjusting the generator using the corrected second adjustment parameter.

7. A GNSS receiver includes a plurality of channels, the channels being designed to track GNSS signals, wherein, At least one channel includes a generator (9), a phase-based filter (6), and a frequency-based filter (7), such that the generator (9) forms a first adjustment loop using the phase-based filter (6) and a second adjustment loop using the frequency-based filter (7), wherein the first adjustment loop is designed to adjust the generator (9) only using a first adjustment parameter (11) in the form of a phase, and wherein the second adjustment loop is designed to adjust the generator (9) only using a second adjustment parameter (12) in the form of a Doppler frequency.

8. The GNSS receiver according to claim 7, wherein, The first adjustment loop and the second adjustment loop are connected in parallel with each other and are both activated when tracking the GNSS signal.

9. The GNSS receiver according to claim 7 or 8, wherein, The first adjustment loop is a scalar phase-locked loop or a vector phase-locked loop or a differential vector phase-locked loop.

10. The GNSS receiver according to any one of claims 7 to 9, wherein, The second adjustment loop is a scalar frequency-locked loop or a vector frequency-locked loop.

11. The GNSS receiver according to any one of claims 7 to 9, wherein, The generator can be adjusted by phase and Doppler frequency or only by Doppler frequency.

12. A control unit for a GNSS receiver, the control unit being designed to perform the method according to any one of claims 1 to 6.

13. A computer program for performing the method according to any one of claims 1 to 6.

14. A computer-readable storage medium, on which the computer program according to claim 13 is stored.

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