The document discusses potential solutions for GPS use indoors. It outlines three proposed approaches: 1) A high sensitivity GPS receiver that can process weaker signals indoors, 2) An active beacon using ultrasonic sensors for stable indoor localization, and 3) The Unscented Kalman Filter algorithm to improve indoor sensor measurements and overcome disturbances. The document suggests combining these approaches in an experiment to track locations within a building.

1. Finding Solutions for GPS Indoors By Fady Rizk

2. What’s GPS? Global Positioning System The idea has been there since the 70’s Became available for commercial use in 1993

3. GPS Receiver

4. How? Receiver receives signals from satellites Using the trilateration method Then computes the data Outputs the results on a map

5. Trilateration

6. The Problem GPS receiver work outdoors … but not indoors

7. Why? 1- Suffers a low signal-to-noise ratio 2- Fails to identify a correlation peak 3- Results in failing to identify a location

8. Problem Conclusion Receiver finds it difficult to detect any signal from the satellites due to reflection, diffraction, fading, refraction, signal attenuation or total obstruction

9. The Need: Finding people in buildings Finding workers in caves Finding locations in huge buildings Finding lost soldiers

10. What to do? High Sensitivity GPS receiver The Beacon (ultrasonic sensor) The Unscented Kalman Filter (UKF)

11. High Sensitivity GPS (chip/receiver) Makes the receivers process signals with the strength of -180 dBW or below Captures 70% of the available signals Increases the carrier to noise ratio

12. The Active Beacon (ultrasonic sensor) Easy signal-processing Estimates a stable and fast localization for a moving object Exhibits robust performances in noisy environments Operates with a low sampling-rate

13. The Unscented Kalman Filter (UKF) Just a better filter and algorithm to use Overcomes severe disturbance for sensor measurement Does not fix the delay

14. Research Idea Combining the researchers’ solutions and experiments into one And Follow researcher's suggestions to fix problems

15. Experiment Environment A building’s last floor Preferably a building that has concrete structure Three measurement positions: 1- A terrace surrounded by four walls, with no roof 2- Room with a roof, with the dimensions of at least 10.2 x 11.2 x 4.2 meters 3- A small corridor surrounded by multiple walls

16. Expected Results The receiver to not suffer of a low signal-to-noise ratio (HS GPS) Receiver process signals with the strength of -180 dBW or below (HS GPS) 70% of the signals and fix the pseudo range problem a stable and fast localization

17. How to value the results? The closer it gets to the GPS receiver’s behavior outdoors, the more this experiment is successful If the outcome of this experiment shows better and more accurate results than what researchers did, the experiment is also considered as a success

18. Thanks for your attention