Roll Rate Estimation for Spinning Projectiles via Single Antenna Signal Correlation

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Solution Overview

Problem

Traditional methods for tracking high roll rates of spinning projectiles are complex and expensive, and often impractical for small guided projectiles due to the requirement for large antenna separation.

Innovation Solution

A directional antenna on the projectile receives signals from a satellite or terrestrial transmitter, and a receiver system correlates the signal with a local model to determine the roll rate and angle based on the time difference between signal reception periods, using a roll feedback loop to calculate the roll rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple separated antennas are used to detect phase differences for tracking roll rate, then measurement precision is improved, but device complexity and size increase

Engineering Contradiction:

Improveroll rate measurement precisionVSAvoidantenna system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the roll rate measurement capability from a multi-antenna phase difference detection system and implements it using a single antenna. The single antenna receives satellite signals and the receiver determines roll rate by analyzing the periodic variation in signal strength caused by the antenna's rotation with the projectile, eliminating the need for multiple antennas while maintaining measurement capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/physical arrangement of multiple separated antennas with a signal processing approach. Instead of using physical antenna separation to generate phase differences, the system uses a single antenna and processes the received signal to extract roll rate information based on the periodic signal strength variations that occur as the antenna rotates

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple separated antennas are used to generate noticeable phase differences, then measurement precision is improved, but the projectile size must increase

Engineering Contradiction:

Improveroll rate measurement precisionVSAvoidantenna separation distance

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from a spatial solution (multiple antennas separated in space) to a temporal solution (single antenna measuring signal strength over time). By analyzing the periodic variation in signal strength as the antenna rotates through different orientations, the system extracts roll rate information without requiring spatial separation of antennas

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If traditional roll rate tracking techniques are implemented, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improveroll rate tracking precisionVSAvoidimplementation cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs a single antenna and standard receiver components that are simpler and less expensive to manufacture than multi-antenna systems. The approach uses off-the-shelf satellite signal reception technology combined with signal processing algorithms to achieve roll rate measurement, reducing manufacturing costs while maintaining functional capability

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent makes the satellite signal receiver serve multiple functions: it provides both position/velocity information and roll rate measurement capability. By utilizing the periodic variation in signal strength already present in the satellite signal reception process, the system extracts additional information (roll rate) without requiring separate dedicated sensors or systems

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9645251B1Estimation of roll and roll rate of a spinning body based on a signal received from a remote transmitter

Publication Date: 2017.05.09 L3HARRIS GLOBAL COMMUNICATIONS INC

AI summary

A receiver determines a roll rate of a spinning projectile that receives a signal from a satellite or terrestrial transmitter at a directional antenna fixed to the projectile. The receiver tracks a code phase and a rate of change thereof of the received signal relative to a local model signal corresponding to the transmitter. A roll correlator of the receiver correlates the received signal with the model signal based on (i) the tracked code phase and rate, and (ii) a roll-correlator integration time assumed to produce a predetermined number N of correlation samples per revolution of the antenna, to produce sequential correlation samples for each of successive revolutions of the antenna. The receiver determines a time difference between successive periods of observed signal reception based on the correlation samples, and determines a roll rate based on the time difference.