# Documentation

This page contains all the information about the project: theoretical algorithms, implementations and all the results obtained so far.

The base paper is available here for free. We detail all the information in the following sections.

NOTE: All files are stored in our public FTP. You can enter the FTP ftp.sgpsproject.org with username anonymous@sgpsproject.org and leave the password blank. Other easier option is to use the following link directly: ftp://anonymous@sgpsproject.org@sgpsproject.org This FTP is not working/necessary anymore.

## Contents |

## Papers and Reports

Newest publications first:

- SGPS paper: base SGPS system and its results. The paper is detailed also in the following sections.
- Idea Feasibility: A project report which studies some options about the feasibility.
- An Energy Efficient Localization Strategy for Outdoor Objects based on Intelligent Light-Intensity Sampling: Main idea of the project. It has also other interesting ideas to implement such tracking or energy efficiency.
- Where Was That Photo Taken?: A very interesting paper which can be interpreted as a prelude of the SGPS idea.

### Related & Interesting Publications

### Talks and Presentations

- SGPS at Linuxec (spanish)
- SGPS at OSHWCON2012 (spanish)
- SGPS at OSHWCON2011 (spanish)

## Theoretical

Base System Description: Definition of the basic system, what are its objectives.

Celestial Model: Formulae to find out the earth coordinates using sunlight.

Simulations: Testing the algorithm supposing a perfect sunrise and sunset detection.

Equation of Time: What it is and how to use it.

Fractional days: Why are a problem and how to manage them.

Limitations: Known limitations so far.

Equinoxes: Why they are a problem.

NOTE: We think that it is better to go to the MAIN SGPS PAPER for the basic theoretical information (the information previously displayed here was pretty much the same).

- Angle-based SGPS: (Under development) Current research on how to compute the localization from the incidence angles of the sun on the earth.

- Incorportating colour information: Such light spectrum, HUE information, and so on.

- SGPSNet: SGPS Network, first steps towards a self-locating Wireless Sensor Network with SGPS.

## Implementations and Software

- Basic C/C++: Base program written in C/C++ to analyze sunlight data.
- Iterative SGPS: Matlab/Octave algorithm to find out the coordinates by Iterative ICM (Inverse Celestial Model).
- Android SGPS: An implementation for testing the SGPS in Android devices.
- SGPSNet: The source code is included the explanatory page.

### Data

- SGPS Results: Files containing the results of the application of the basic SGPS algorithm to the NOAA FTP dataset.
- SGPS Network results: Given together with the source code. The results are in data/results.mat. More info in the README file included and in SGPSNet.

### Results

The main experiment we carried out is detailed in the MAIN SGPS PAPER using NOAA FTP dataset and the Basic C/C++ program.

## References

Please, refer to the MAIN SGPS PAPER to find the related references.

## Other Interesting Documentation

- AA+ Library: It is a C++ implementation for the algorithms as presented in the book "Astronomical Algorithms" by Jean Meeus.
- LDR GPS: The same idea as SPGS but a little bit simpler. Based on the AVR Butterfly module.