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On the design of fixed-gain tracking filters by pole placement: Or an introduction to applied signals-and-systems theory for engineers

Systems and Control · Submitted 1 Oct 2021

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim It is suggested that the arbitrary placement of closed-loop state-observer poles is a simple and intuitive way of tuning the transient and steady-state response of a fixed-gain tracking filter when prior distributions are unknown.

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arXiv ID2110.00153 (version 2)
Pith IDUAJ524CF, Pith's permanent record of this paper and its review
CitationHugh Lachlan Kennedy. "On the design of fixed-gain tracking filters by pole placement: Or an introduction to applied signals-and-systems theory for engineers." arXiv:2110.00153 (2021). https://pith.science/paper/UAJ524CF
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Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-09-23: 1 request, 8,421 input tokens.

What the abstract itself states, as probabilities: claims first 0.05 · states limitation 0.33 · human participants 0.02 · controlled comparison 0.15 · randomized assignment 0.01 · states quantitative result 0.15 · compares with prior results 0.89 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; .

The Kalman filter computes the optimal variable-gain using prior knowledge of the initial state and random (process and measurement) noise distributions, which are assumed to be Gaussian with known variance. However, when these distributions are unknown, the Kalman filter is not necessarily optimal and other simpler state-estimators, such as fixed-gain ({\alpha}, {\alpha}-\b{eta} or {\alpha}-\b{eta}-{\gamma} etc.) filters may be sufficient. When such filters are used as low-complexity state-estimators in embedded tracking systems, the fixed gain parameters are usually set equal to the steady-state gains of the corresponding Kalman filter. An alternative procedure, that does not rely prior distributions, based on Luenberger observers, is presented here. It is suggested that the arbitrary placement of closed-loop state-observer poles is a simple and intuitive way of tuning the transient and steady-state response of a fixed-gain tracking filter when prior distributions are unknown. All poles are placed inside the unit circle on the positive real axis of the complex z-plane at p for a well damped response and a configurable bandwidth. Transient bias errors, e.g. due to target manoeuvres or process modelling errors, decrease as p=0 is approached for a wider bandwidth. Steady-state random errors, e.g. due to sensor noise, decrease as p=1 is approached for a narrower bandwidth. Thus the p parameter (with 0<p<1) may be interpreted as a dimensionless smoothing factor. This tutorial-style report examines state-observer design by pole placement, which is a standard procedure for feedback controls but unusual for tracking filters, due to the success and popularity of the Kalman filter. As Bayesian trackers are designed via statistical modelling, not by pole-zero placement in the complex plane, the underlying principles of linear time-invariant signals and systems are also reviewed.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 The Kalman filter computes the optimal variable-gain using prior knowledge of the initial state and random (process and measurement) noise distributions, which are assumed to be Gaussian with known variance. background 1.00 0.04 0.03 asserted 1.00
s1 However, when these distributions are unknown, the Kalman filter is not necessarily optimal and other simpler state-estimators, such as fixed-gain ({\alpha}, {\alpha}-\b{eta} or {\alpha}-\b{eta}-{\gamma} etc.) filters may be sufficient. background 0.82 0.06 0.06 hedged possibility 0.69
s2 When such filters are used as low-complexity state-estimators in embedded tracking systems, the fixed gain parameters are usually set equal to the steady-state gains of the corresponding Kalman filter. background 1.00 0.06 0.04 asserted 0.95
s3 An alternative procedure, that does not rely prior distributions, based on Luenberger observers, is presented here. contribution 0.83 0.76 0.12 asserted 0.99
s4 It is suggested that the arbitrary placement of closed-loop state-observer poles is a simple and intuitive way of tuning the transient and steady-state response of a fixed-gain tracking filter when prior distributions are unknown. method 0.51 0.41 0.69 hedged possibility 0.99
s5 All poles are placed inside the unit circle on the positive real axis of the complex z-plane at p for a well damped response and a configurable bandwidth. method 0.97 0.49 0.18 asserted 0.99
s6 Transient bias errors, e.g. due to target manoeuvres or process modelling errors, decrease as p=0 is approached for a wider bandwidth. result 0.91 0.53 0.10 asserted 1.00
s7 Steady-state random errors, e.g. due to sensor noise, decrease as p=1 is approached for a narrower bandwidth. result 0.93 0.50 0.11 asserted 1.00
s8 Thus the p parameter (with 0<p<1) may be interpreted as a dimensionless smoothing factor. interpretation 1.00 0.59 0.25 hedged possibility 0.98
s9 This tutorial-style report examines state-observer design by pole placement, which is a standard procedure for feedback controls but unusual for tracking filters, due to the success and popularity of the Kalman filter. background 0.53 0.23 0.08 asserted 0.98
s10 As Bayesian trackers are designed via statistical modelling, not by pole-zero placement in the complex plane, the underlying principles of linear time-invariant signals and systems are also reviewed. background 0.72 0.10 0.05 asserted 0.98

What kind of paper the classifier reports this is: method or tool 0.99 · evidence from argument 0.67.

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Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper
Original abstract

The Kalman filter computes the optimal variable-gain using prior knowledge of the initial state and random (process and measurement) noise distributions, which are assumed to be Gaussian with known variance. However, when these distributions are unknown, the Kalman filter is not necessarily optimal and other simpler state-estimators, such as fixed-gain ({\alpha}, {\alpha}-\b{eta} or {\alpha}-\b{eta}-{\gamma} etc.) filters may be sufficient. When such filters are used as low-complexity state-estimators in embedded tracking systems, the fixed gain parameters are usually set equal to the steady-state gains of the corresponding Kalman filter. An alternative procedure, that does not rely prior distributions, based on Luenberger observers, is presented here. It is suggested that the arbitrary placement of closed-loop state-observer poles is a simple and intuitive way of tuning the transient and steady-state response of a fixed-gain tracking filter when prior distributions are unknown. All poles are placed inside the unit circle on the positive real axis of the complex z-plane at p for a well damped response and a configurable bandwidth. Transient bias errors, e.g. due to target manoeuvres or process modelling errors, decrease as p=0 is approached for a wider bandwidth. Steady-state random errors, e.g. due to sensor noise, decrease as p=1 is approached for a narrower bandwidth. Thus the p parameter (with 0<p<1) may be interpreted as a dimensionless smoothing factor. This tutorial-style report examines state-observer design by pole placement, which is a standard procedure for feedback controls but unusual for tracking filters, due to the success and popularity of the Kalman filter. As Bayesian trackers are designed via statistical modelling, not by pole-zero placement in the complex plane, the underlying principles of linear time-invariant signals and systems are also reviewed.

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