Student Research Showcases Satellite Formation Flying Using STK

  • Sep 14, 2020
  • Blog Post

At AGI, we’re always excited to learn about the great work of the students who participate in our Educational Alliance Program (EAP) and the many ways that they apply Systems Tool Kit (STK) to their problems. Today we are very happy to highlight the work of Yazan Chihabi and Steve Ulrich, "Spacecraft Formation Guidance Law using a State Transition Matrix with Gravitational, Drag and Third-Body Perturbations," which they presented during January’s AIAA SciTech Conference in Orlando.

Satellite formation flying is a strategy that groups inexpensive, small satellites to complete an objective. These “small sats” are easy to replace and require less power than a single, large satellite. Formation flying is certain to become a common approach for future LEO missions, but one that will demand increasingly sophisticated coordination capabilities for these satellites. Formation flying missions require an “accurate and efficient dynamic model, within the guidance system, to calculate and control the desired relative motion,” write Chihabi & Ulrich.

In their work, Chihabi and Ulrich formulate a solution: A novel analytical dynamic model that accounts for fifth zonal gravitational perturbations, fourth order third-body perturbations, and drag forces over time. Their approach builds upon previously developed methods. However, the new analytical solution “propagate[s] the relative orbital elements by [multiplying] constant matrices with time and initial relative orbital elements,” the paper states, as opposed to previous methods that required recalculation of the matrices. They validated and verified their approach with STK.

Using their algorithm, Chihabi and Ulrich calculated the “initial conditions of the chaser spacecraft so that it may drift (without the use of control actuation) into a desired set of coordinates with respect to the target. The conditions were then initialized in STK with HPOP to verify, validate, and visualize the relative motion of the spacecraft

Learn more about Yazan Chihabi and Steve Ulrich's solution here or watching the supporting STK video. To learn more about the EAP, visit or email us at