1 Place Proper DISTRIBUTION STATEMENT Here Integrity  Service  Excellence MAX REVIEW Cooperative Navigation in GPS Denied Environments 19 April 2013 Control Automation Branch, Aerospace Systems Directorate Air Force Research Laboratory

2 Place Proper DISTRIBUTION STATEMENT Here Overview Long-term Objective: Design control strategies such that a team of UAVs can navigate from one location to another in GPS denied environments. Why? “Further key emphasis must be placed on research to support increased freedom of operations in contested or denied environments…” (from TH) Approach: Teaming and cooperation  Information acquisition (main purpose)  Reduced cost  Improved robustness Research:  What information is needed?  How to obtain it?  Any optimality? Our Expertise Portfolio:  Cooperative control  Stochastic control  Optimal control  Decentralized control The basic idea is to have a team of UAVs maintain a desired rigid formation and rotate around some designated UAV (on top of a UGS) until one UAV in the team connects to a subsequent UGS. UAV Autonomous Control in Denied Environments.

3 Place Proper DISTRIBUTION STATEMENT Here Steps and Tasks  2-UAV navigation (a basic scenario) Navigation of two UAVs from one location to next  Cooperative estimation Estimation of inter-UAV distances  Structure estimation Estimation of the formation of the team  Structure maneuver A match between the current formation and the desired formation  Structure rotation Rotation of the formation CW or CCW  Synthesis A closed-loop point of view costbenefit Note: We pay the price of “teaming and cooperation” to get “information”.

4 Place Proper DISTRIBUTION STATEMENT Here Circumnavigation Circumnavigation is one fundamental research problem.

5 Place Proper DISTRIBUTION STATEMENT Here UAV Dynamics & Control Algorithm UAV Dynamics Control Algorithm Range & Range Rate are needed for control algorithm –Assume a known, fixed velocity

6 Place Proper DISTRIBUTION STATEMENT Here Algorithm Motivation Control Algorithm revisited The (desired) rate of change for –UAV heads toward tangent on desired orbit Rate of change of given the UAV’s current heading

7 Place Proper DISTRIBUTION STATEMENT Here Result Note: A proof of the theorem can be found in a recent paper submitted to CDC13.

8 Place Proper DISTRIBUTION STATEMENT Here Ongoing Research What if is unavailable?

9 Place Proper DISTRIBUTION STATEMENT Here Challenges

10 Place Proper DISTRIBUTION STATEMENT Here Additional Questions Consideration of uncertainties:  Wind  Measurement noises  Latency  Loss of package Other types of measurements:  Heading (e.g., magnetometer)  Bearing (e.g., VOR type of concept) Note: Additional measurements can be useful in two ways  Flexibility in the controller design  Improved performance by information fusion techniques (e.g., Kalman Filtering)

11 DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution