Adaptive Loop-Bandwidth Control Algorithm for Scalar Tracking Loops

Abstract In traditional satellite navigation receivers, the parameters of tracking loop such as loop bandwidth and integration time are usually set in the design of the receivers according to different scenarios. The signal tracking performance is limited in traditional receivers. In addition, when the tracking ability of weak signals is improved by extending the integration time, negative effect of residual frequency error becomes more and more serious with extension of the integration time. To solve these problems, this paper presents out research on receiver tracking algorithms and proposes an optimised tracking algorithm with inertial information. The receiver loop filter is designed based on Kalman filter, reducing the phase jitter caused by thermal noise in the weak signal environment and improving the signal tracking sensitivity. To confirm the feasibility of the proposed algorithm, simulation tests are conducted.

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A Ku-Band Fractional-N Frequency Synthesizer with Adaptive Loop Bandwidth Control

Electronics ◽

10.3390/electronics10020109 ◽

2021 ◽

Vol 10 (2) ◽

pp. 109

Author(s):

Youming Zhang ◽

Xusheng Tang ◽

Zhennan Wei ◽

Kaiye Bao ◽

Nan Jiang

Keyword(s):

Phase Noise ◽

Frequency Synthesizer ◽

Frequency Tuning ◽

Cmos Technology ◽

Voltage Controlled Oscillator ◽

Loop Filter ◽

Chip Area ◽

Loop Bandwidth ◽

Bandwidth Control ◽

Ku Band

This paper presents a Ku-band fractional-N frequency synthesizer with adaptive loop bandwidth control (ALBC) to speed up the lock settling process and meanwhile ensure better phase noise and spur performance. The theoretical analysis and circuits implementation are discussed in detail. Other key modules of the frequency synthesizer such as broadband voltage-controlled oscillator (VCO) with auto frequency calibration (AFC) and programable frequency divider/charge pump/loop filter are designed for integrity and flexible configuration. The proposed frequency synthesizer is fabricated in 0.13 μm CMOS technology occupying 1.14 × 1.18 mm2 area including ESD/IOs and pads, and the area of the ALBC is only 55 × 76 μm2. The out frequency can cover from 11.37 GHz to 14.8 GHz with a frequency tuning range (FTR) of 26.2%. The phase noise is −112.5 dBc/Hz @ 1 MHz and −122.4 dBc/Hz @ 3 MHz at 13 GHz carrier frequency. Thanks to the proposed ALBC, the lock-time can be shortened by about 30% from about 36 μs to 24 μs. The chip area and power consumption of the proposed ALBC technology are slight, but the beneficial effect is significant.

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A -90dBc@10kHz phase noise fractional-N frequency synthesizer with accurate loop bandwidth control circuit

Digest of Technical Papers. 2005 Symposium on VLSI Circuits, 2005. ◽

10.1109/vlsic.2005.1469332 ◽

2005 ◽

Cited By ~ 3

Author(s):

T. Morie ◽

S. Dosho ◽

K. Okamoto ◽

Y. Yamada ◽

K. Sogawa

Keyword(s):

Phase Noise ◽

Frequency Synthesizer ◽

Control Circuit ◽

Loop Bandwidth ◽

Bandwidth Control

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Evaluation of Adaptive Loop-Bandwidth Tracking Techniques in GNSS Receivers

Sensors ◽

10.3390/s21020502 ◽

2021 ◽

Vol 21 (2) ◽

pp. 502

Author(s):

Iñigo Cortés ◽

Johannes Rossouw van der Merwe ◽

Jari Nurmi ◽

Alexander Rügamer ◽

Wolfgang Felber

Keyword(s):

System Performance ◽

Time Complexity ◽

Satellite System ◽

Optimal Performance ◽

Tracking Performance ◽

System Perspective ◽

Adaptive Tracking ◽

Loop Bandwidth ◽

Tracking Loops ◽

Gnss Receivers

Global navigation satellite system (GNSS) receivers use tracking loops to lock onto GNSS signals. Fixed loop settings limit the tracking performance against noise, receiver dynamics, and the current scenario. Adaptive tracking loops adjust these settings to achieve optimal performance for a given scenario. This paper evaluates the performance and complexity of state-of-the-art adaptive scalar tracking techniques used in modern digital GNSS receivers. Ideally, a tracking channel should be adjusted to both noisy and dynamic environments for optimal performance, defined by tracking precision and loop robustness. The difference between the average tracking jitter of the discriminator’s output and the square-root Cramér-Rao bound (CRB) indicates the loops’ tracking capability. The ability to maintain lock characterizes the robustness in highly dynamic scenarios. From a system perspective, the average lock indicator is chosen as a metric to measure the performance in terms of precision, whereas the average number of visible satellites being tracked indicates the system’s robustness against dynamics. The average of these metrics’ product at different noise levels leads to a reliable system performance metric. Adaptive tracking techniques, such as the fast adaptive bandwidth (FAB), the fuzzy logic (FL), and the loop-bandwidth control algorithm (LBCA), facilitate a trade-off for optimal performance. These adaptive tracking techniques are implemented in an open software interface GNSS hardware receiver. All three methods steer a third-order adaptive phase locked loop (PLL) and are tested in simulated scenarios emulating static and high-dynamic vehicular conditions. The measured tracking performance, system performance, and time complexity of each algorithm present a detailed analysis of the adaptive techniques. The results show that the LBCA with a piece-wise linear approximation is above the other adaptive loop-bandwidth tracking techniques while preserving the best performance and lowest time complexity. This technique achieves superior static and dynamic system performance being 1.5 times more complex than the traditional tracking loop.

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