Determination of guided-munition roll orientation

A system for determination of a guided munition orientation, the system comprising:

• an accelerometer configured to measure a lateral acceleration vector of the guided munition, wherein the accelerometer comprises a first acceleration sensor and a second acceleration sensor, the second acceleration sensor being orthogonal to the first acceleration sensor;
• a vector addition circuit configured to calculate the lateral acceleration vector as a sum of data provided by the first acceleration sensor and data provided by the second acceleration sensor;
• a vector division circuit configured to calculate a ratio of the lateral acceleration vector measurement to a velocity of the guided munition, to generate an estimated lateral turn rate vector of the guided munition;
• a temporal integration circuit configured to integrate the estimated lateral turn rate vector, over a period of time that is anytime between launch and impact, to generate a first type of predicted attitude change;
• a lateral turn rate sensor configured to measure a lateral turn rate vector of the guided munition;
• wherein the lateral turn rate sensor comprises a first turn rate sensor and a second turn rate sensor, the second turn rate sensor orthogonal to the first turn rate sensor;
• and wherein the vector addition circuit is configured to calculate the lateral turn rate vector as a sum of data provided by the first turn rate sensor and data provided by the second turn rate sensor;
• the temporal integration circuit is further configured to integrate the measured lateral turn rate vector, over the period of time associated with flight of the guided munition, to generate a second type of predicted attitude change;
• and
• a vector subtraction circuit configured to calculate a gravity direction vector based on a difference between the first type of predicted attitude change and the second type of predicted attitude change.

At least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by one or more processors, result in the following operations for determination of a guided munition orientation, the operations comprising:

• calculating a ratio of a lateral acceleration vector measurement of the guided munition to a velocity of the guided munition, to generate an estimated lateral turn rate vector of the guided munition;
• integrating the estimated lateral turn rate vector, over a period of time associated with flight of the guided munition, to generate a first type of predicted attitude change;
• obtaining a lateral turn rate vector measurement of the guided munition;
• integrating the measured lateral turn rate vector, over the period of time that is anytime between launch and impact, to generate a second type of predicted attitude change;
• and
• calculating a gravity direction vector based on a difference between the first type of predicted attitude change and the second type of predicted attitude change.