Abstract

As roll angle measurement is essential for two-dimensional course correction fuze (2-D CCF) technology, a real-time estimation of roll angle of spinning projectile by single-axis magnetometer is studied. Based on the measurement model, a second-order frequency-locked loop (FLL)-assisted third-order phase-locked loop (PLL) is designed to obtain rolling information from magnetic signals, which is less dependent on the amplitude and able to reduce effect from geomagnetic blind area. Method of parameters optimization of tracking loop is discussed in the circumstance of different speed and it is verified by six degrees of freedom (six degrees of freedom (DoF)) trajectory. Also, the measurement error is analyzed to improve the accuracy of designed system. At last, experiments on rotary table are carried out to validate the proposed method indicating the designed system is able to track both phase and speed accurately and stably. The standard deviation (SD) of phase error is no more than 3°.

Highlights

  • The research on smart ammunitions has long been a popular subject for the conventional uncontrolled projectiles cannot satisfy the requirements of modern warfare, high efficiency, accuracy, as well as low cost and collateral damage [1,2]

  • The trajectory correction projectile is based on the transformation of conventional spinning projectiles through trajectory correction fuze (CCF)

  • To overcome the weakness of traditional method based on geomagnetism, some institutes presented methods based on time–frequency domain analysis [22] and frequency-locked loop [23] information obtained from single-axis magnetic sensor rather than multiple outputs or operation of inverse trigonometric function

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Summary

Introduction

The research on smart ammunitions has long been a popular subject for the conventional uncontrolled projectiles cannot satisfy the requirements of modern warfare, high efficiency, accuracy, as well as low cost and collateral damage [1,2]. To overcome the weakness of traditional method based on geomagnetism, some institutes presented methods based on time–frequency domain analysis [22] and frequency-locked loop [23] information obtained from single-axis magnetic sensor rather than multiple outputs or operation of inverse trigonometric function They managed to measure the rotational speed but no progress in roll angle. Unlike the conventional measurement by an inverse trigonometric operation based on amplitude of multiple outputs, a second-order frequency-locked loop (FLL)-assisted third-order phase-locked loop (PLL) is designed to obtain the phase information of the output of single-axis magnetometer, which is relevant to rolling attitude. It is able to avoid the measurement error from conventional ways and reduce effect from blind area, reaching cost-reduction, low-power consumption, as well as miniaturation This novel method is proposed to obtain rolling attitude of kinds of spin stabilized projectiles launched by howitzer or tank.

Measurement System Modeling
Description of Geomagnetic Vector in a North-East-Down Coordinate System
Coordinate Transforamtions
Description
Method to Obtain the Rolling Information
Process
Design of Tracking Loop
Analysis of Performance and Parameters Optimized
Larger ωperformance
Hz tonoise
Hz toon300
Error Analysis of Tracking Loop
Error From Compensation Angle
17. Compensation
Error Caused by Geomagnetic
Experiments
19. Experiments
Design of of Hardware
20. Design
Operation of Experiments
Results and Analysis
Parameters
Results of group
22.Results
Conclusions

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