1. Loran Integrity Performance Panel Integrity Fault Tree for Loran Sherman Lo Second LORIPP Meeting Portland, OR September 23-24, 2002

2. Loran Integrity Performance Panel Outline Integrity Fault Tree Loran Threat List  Transmitter  Propagation  Receiver Error Allocations Fault Document Conclusions

3. Loran Integrity Performance Panel Goals Discuss Listing of Faults Agree on Form of Top Level Integrity Fault Tree Use Fault Tree for Analysis & Documents Make Documents Available to LORIPP Members

4. Loran Integrity Performance Panel Fault Tree Design Logical Means of Allocating Fault Probabilities  Design to Specific Analysis (i.e. threat monitors, error bounds)  In Loran Navigation, Design Towards HPL Error Components Bookkeeping to Verify Not Exceeding Maximum Level of HMI  Comprehensively Exhaustive  Mutually Exclusive (Desired)

5. Loran Integrity Performance Panel Integrity Fault Tree Phase Error Cycle Error

6. Loran Integrity Performance Panel HPL Equation  is the factor on standard deviations of the overbounding gaussian needed to achieve the desired confidence level. I.e.  =5.33 results in a probability of an error exceeding that value of 0.98x10 -7. K i are the weighting factors derived from the pseudoinverse of the geometry matrix  i is the standard deviation of the normal distribution that overbounds the randomly distributed errors  i an overbound for the correlated bias terms  i an overbound for the uncorrelated bias terms

7. Loran Integrity Performance Panel Example Fault Tree

8. Loran Integrity Performance Panel Loran Threats (Transmitter) Integrity Faults  Timing Jump  Timing Drift  Pulse Shape Distortion Tube Type Transmitter (TTX)  Frequency & Timing Equipment Cesium Freq. Standard, Timer, Frequency Patch Panel, Frequency Distribution Amp, Timer Set Control  Pulse Generation & Transmission Pulse Generator, Transmitter, Antenna, Transmitter Interface Unit, Antenna Coupler  Other Equipment Used for collecting, recording, and reporting

9. Loran Integrity Performance Panel Loran Threats (Transmitter) Solid State Transmitter (SSX)  Pulse Amplitude & Timing Controller (PATCO) Display ECD, Timing Logic, Loop Control, Microprocessor Boards, Power Supplies, Switches  Signal Distribution Amplifier (SDA) Distribution Boards  Half Cycle Generators (HCG) Control Logic Boards, FD&C Board, AC & C1 Regulator Boards, Power Supplies, Megatron, Megatron Charge Assembly  Coupling Network (CN)  Coupling Equipment  Transmit Hardware Transmitter Bus Work, Antenna Coupler, Ground Plane

10. Loran Integrity Performance Panel Loran Threats (Propagation Prediction Errors) Additional Secondary Factor Prediction Errors ECD Prediction Error Signal Strength Prediction (Terrain Effects)

11. Loran Integrity Performance Panel Loran Threats (Receiver Interference) Atmospheric Effects  Atmospheric Noise  P Static (is this availability?)  Lightning (Near Field) Interference (Man Made)  Sky Wave Interference  Cross Rate Interference  CW Interference  Locally Generated Platform Noise

12. Loran Integrity Performance Panel Loran Threats (Receiver) Hardware  Receiver Antenna Bias  Thermal Noise  Bandpass Filter  Locally Generated Platform Noise Software  Cycle Tracking  Doppler Tracking  Signal Tracking

13. Loran Integrity Performance Panel Example Breakdown - SSX

14. Loran Integrity Performance Panel Allocation

15. Loran Integrity Performance Panel Documentation For each threat:  Description  Algorithm Description  Integrity Algorithm Verification  Validation of Algorithm  Assumed Conditions  Dependencies Correspond to Fault Tree

16. Loran Integrity Performance Panel Conclusions The Integrity Fault Tree Exists to Facilitate Proof that We Meet Integrity Requirements Designed to Correspond to Requirements for HPL Calculation (Errors & Bounds) Should Aid in Documentation

17. Loran Integrity Performance Panel Loran Threats (Propagation) Additional Secondary Factor Prediction Errors Atmospheric Noise P Static Sky Wave Interference Cross Rate Interference

18. Loran Integrity Performance Panel Loran Threats (Propagation) Atmospheric Effects  Additional Secondary Factor Prediction Errors  Atmospheric Noise  P Static (is this availability?)  Lightning (Near Field) Interference (Man Made)  Sky Wave Interference  Cross Rate Interference  CW Interference

19. Loran Integrity Performance Panel Loran Threats (Receiver) Hardware  Receiver Antenna Bias  Thermal Noise  Bandpass Filter Software  Cycle Tracking  Doppler Tracking  Signal Tracking