# 🏢 Indoor Localization and Navigation System

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> A deep learning-based indoor positioning system with real-time A\* navigation, achieving **0–3 meter accuracy** — a significant improvement over existing methods.

---

## 📌 Overview

Indoor localization is a challenging problem due to the lack of GPS signals inside buildings and complex environments with walls, obstacles, and interference. Many existing systems rely on signal strength, Wi-Fi fingerprints, or other heuristics, but these approaches often have limited accuracy, with errors ranging from **0 to 5 meters**.

This project builds upon the methodology proposed in the **WiDeep paper** with two key improvements:

1. ✅ Replaced the weighted-sum approach with a **trainable softmax-based layer** for position approximation.
2. ✅ Implemented a **grid-based mapping system** with the **A\* algorithm** for path planning and real-time navigation.

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## 🧠 Approach

### Position Approximation

The core of the localization method is a custom Keras layer called **`PositionAproxmator`**:

- Takes a predefined list of possible positions in the environment (`PlacesPosition`).
- Learns a small **trainable offset weight** `W` for each position, allowing the model to refine predicted locations.
- Computes the final position via matrix multiplication of probabilities with `(PlacesPosition + W)`.

```python
import tensorflow as tf
from tensorflow import keras

class PositionAproxmator(keras.layers.Layer):
    def __init__(self, PlacesPosition, name="PositionAproxmator"):
        super(PositionAproxmator, self).__init__()
        self.PlacesPosition = tf.constant(PlacesPosition, dtype=tf.float32, name="PlacesPositions")

    def build(self, inputs_shape):
        self.W = self.add_weight(
            shape=(inputs_shape[1], 2),
            trainable=True,
            dtype=tf.float32,
            name="PlacesWeight"
        )

    def call(self, Probilites):
        return Probilites @ (self.PlacesPosition + self.W)

    def get_config(self):
        config = super().get_config()
        config.update({"PlacesPosition": self.PlacesPosition})
        return config
```

---

### 🗺️ Mapping & Navigation

Once the position is estimated, the system uses a **grid-based map** of the environment and applies the **A\* algorithm** to plan the optimal path from the current location to a target — enabling real-time indoor navigation.

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## 🔄 System Workflow

```
Input Probabilities
       │
       ▼
Softmax Layer          ← Normalizes probabilities
       │
       ▼
PositionAproxmator     ← PlacesPosition + learned W offsets
       │
       ▼
Predicted (x, y) Position
       │
       ▼
Grid Map Representation
       │
       ▼
A* Path Planning
       │
       ▼
Navigation Instructions / Path
```

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## 📊 Results

| System         | Error Range  |
|----------------|-------------|
| **My System**  | **0 – 3 m** |
| WiDeep Paper   | 0 – 5 m     |

By integrating mapping and A\* navigation, the system also generates accurate indoor routes, making it practical for real-world applications.

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## 🛠️ Tech Stack

| Category             | Tools / Libraries                        |
|----------------------|------------------------------------------|
| Language             | Python 3.10                              |
| Deep Learning        | TensorFlow / Keras                       |
| Data Processing      | NumPy, Pandas                            |
| Visualization        | Matplotlib, Seaborn                      |
| Navigation           | Custom Grid Map + A\* Algorithm          |

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## 🚀 Future Work

- [ ] Real-time deployment on mobile devices
- [ ] Multi-floor building support
- [ ] Sensor fusion: Bluetooth, UWB, IMU
- [ ] Dynamic obstacle avoidance

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## 📬 Contact

Feel free to reach out for collaborations, discussions, or contributions!