Patent ID: 8561898
Filing Date: 2013-10-22
Classification: F41G,F42B,G01S

Abstract:
1. An apparatus comprising: electronic circuitry mountable on a projectile including an array of at least four thermopiles placed around the circumference thereof such that for any rotation of the projectile during flight thereof, at least a pair of the thermopiles have upwardly-facing fields of view referenced to an earth-fixed coordinate system, wherein the electronic circuitry is configured to receive output voltage data from the array, and determine the pair of upwardly-facing thermopiles based on the output voltage data from the array, the respective pair of thermopiles including a thermopile p and next adjacent thermopile p+1, wherein the electronic circuitry is configured to determine a ratio of the output voltage data from thermopiles p and p+1, and apply the ratio to a function associating, for any pair of thermopiles n and n+1, a ratio of output voltage data from thermopiles n and n+1, and a roll angle θ wherein the ratio of the output voltage data from thermopiles p and p+1 is applied to the function to determine a roll angle θ