Inertial Pointing Software

SWITCH TO API

Description

This module is designed to work as the pointing program in a ADCS software chain as shown in the figure below:

This module outputs a target reference frame $\mathcal{R}:[{\hat{r}}_1,{\hat{r}}_2,{\hat{r}}_3]$ that is this aligned with the inertially fixed frame ${\mathcal{R}}_0:[{\hat{e}}_1,{\hat{e}}_2,{\hat{e}}_3]$ e.g. the Earth-Centered Inertial (ECI) frame for the case where the SPICE zero-base is set to Earth.

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Example Use Cases

• Compute the inertial 3D reference frame for pointing applications: Constructs a reference frame with a fixed orientation and zero body rates in the inertial frame e.g. de-tumble.

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Module Implementation

This module requires a desired reference orientation ${\sigma }_{R_{0}N}$. This input is set once and is fixed in the simulation. As the fixed-pointing is inertial, the output attitude reference message describing the target reference frame $\mathcal{R}$ in $\mathcal{N}$ is:

$$\begin{gathered} {\sigma }_{RN}={\sigma }_{R_{0}N} \\ {\omega }_{RN}={\dot{\omega }}_{RN}=0 \end{gathered}$$