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The purpose of this research is to compare the effects of two filtering routines which may be used to integrate Inertial Navigation System (INS) and Global Positioning System (GPS) data to determine certain state vector elements. The two filtering routines are: 1) the ordinary Kalman Filter, and 2) a Two-Stage Least- Squares Procedure, which will be referred to as the 2-Stage Filter. Using the Kalman Filter to determine state vector elements, the vector quantities can be affected when system error is introduced into the model. Theoretically, the 2-Stage Filter is more robust, that is, it should be able to determine accurately the state vector elements despite the presence of errors (Schaffrin 1991) This research will attempt to verify the 2-Stage Filter is, in fact, a more robust filter than the Kalman Filter.

The purpose of this research is to compare the effects of two filtering routines which may be used to integrate Inertial Navigation System (INS) and Global Positioning System (GPS) data to determine certain state vector elements. The two filtering routines are: 1) the ordinary Kalman Filter, and 2) a Two-Stage Least- Squares Procedure, which will be referred to as the 2-Stage Filter. Using the Kalman Filter to determine state vector elements, the vector quantities can be affected when system error is introduced into the model. Theoretically, the 2-Stage Filter is more robust, that is, it should be able to determine accurately the state vector elements despite the presence of errors (Schaffrin 1991) This research will attempt to verify the 2-Stage Filter is, in fact, a more robust filter than the Kalman Filter.

The goal of our AFOSR proposal was to study the feasibility, characteristics and limitations of using two Airborne Laser Scanners (ALS) mounted on an Uninhabited Airborne Vehicle (UAV) to aid its Inertial Measurement Unit (IMU) in unknown terrain environments. One area of interest to AFRL is the ability to navigate in GPS-denied environments where prior information about the terrain the UAV is traversing, is unknown. Conventional TRN schemes are inadequate since they all require prior terrain information in the form of a terrain elevation database. Ohio University s proposed concept of using Dual Airborne Laser Scanner (Dual ALS) meets the requirement of not needing prior terrain information. Conceptually similar to an Inertial Navigator, Dual ALS is a dead-reckoning system that keeps track of a vehicle s position state changes over time, since initialization. The Dual ALS error states can then be used to correct or reset the IMU states, thus effectively constraining its drift error. Simulation results provided in this final report demonstrate that the concept works extremely well with residual horizontal drift errors of magnitudes as small as 60 meters per hour.

Included in this collection are the first two stories featuring that wonderfully wacky dream girl temptress Toffee! Stories include:<br> "I'll Dream of You": Toffee was just a girl in Marc Pillsworth's dreams—until he awoke one day to find the dream a reality.<br> "You Can't Scare Me!": Toffee knew that Marc Pillsworth was in trouble again, so she came out of his subconscious mind to help him. - Summary by Ben Tucker & Fantastic Adventures

2Toffee Takes A Trip

By Henry Farrell

Marc Pillsworth decided he needed a vacation—so he went on a trip. But where Marc went, Toffee followed—with trouble. - Summary by Fantastic Adventures July 1947

3Toffee Haunts a Ghost

By Henry Farrell

Having Toffee the "dream-girl" around was bad enough for Marc, but a ghost named George was just too much. - Summary by Fantastic Adventures, November 1947