High Speed Digital Systems Lab May 2009

1. INS/GPS navigation INS/GPS navigation using a particle filter Midterm presentation Developers: Lital Cohen and AyalOzer Mentor: Michael Yampolsky High Speed Digital Systems Lab May 2009

2. INS/GPS navigationAgenda • Overview and review • Interface • Architecture • Difficulties and solutions • Timetable

3. INS/GPS navigation Theoretical Background • Benefit from the advantages of combining INS and GPS • 30K particles, each representing a probability of the object’s state • Every 10ms the state is updated according to the INS • Every 1 second we receive a GPS reading, according to which we give the appropriate weight to each particle • Sometimes we need to resample & regularize to avoid degeneration

4. INS/GPS navigationProject Objectives • Convert quaternions to Euler angles • Calculate the covariance matrix and its root • Complete the above tasks in less than 10ms • Minimize the area used on the FPGA to implement the algorithm

5. INS/GPS navigationSystem Inputs & Outputs INPUT • The particlevectors: Xk1..N • The weight vector: wk • The estimated state vector: Xk OUTPUT • Euler angles particlevectors: ξk1..N • Euler Angles estimated state vector: ξk • The covariance matrix: Sk • The covariance root matrix: DkT ^ ^

6. Angle Converter + Discontinuity fix ^ ^ X w ξ Root Matrix Dk Multiplier INS/GPS navigationTop Level Architecture The main pipeline: Xi+2 Xi+1 Xi ξi Covariance Matrix Builder ξi-1 ξi-2 Root Matrix Builder Σ

7. ^ ξ ^ X INS/GPS navigationAngle Converter Architecture Angle Converter + Discontinuity fix Xi+2 Xi+1 atan LUT Xi ξi Discontinuity fix ξi-1 atan LUT ξi-2 asin LUT

8. w INS/GPS navigation Cov. Matrix Arc. phase 1 ξ1 Mult 1 ξi+2 ξi+1 ξi ξ2 Mult 2 Weight Mult ξ(17)ξ(2) ξ(1) ξ17 Mult 17

9. INS/GPS navigation Cov. Matrix Arc. phase 2 S column i Σ RAM register Adder S column i-1 mult. vector

10. Root Matrix Dk INS/GPS navigation Root Matrix Architecture Cholesky Decomposition C++ code Σ RAM (holding Sk )

11. INS/GPS navigation Difficulties and solutions • Implementation of atan and asin functions • LUT ROM vs. Cordic or Taylor algorithms • The Cholesky decomposition • NIOS II core vs. hardware implementation

12. INS/GPS navigation Difficulties and solutions • Angle discontinuity problem • Using the estimated state vector we choose the discontinuity point • Calculation scalability • Duplication of the Covariance Matrix Builder

13. INS/GPS navigationTimetable Task Schedule • Design June 15th – August 31th • Simulation & synthesis Sept. 1st – Sept. 30th • Optimization & result Oct. 1st – Oct. 30th analysis