Introduction
WiFi and Bluetooth positioning technologies are commonly used for indoor localization and tracking. Unlike GPS, which struggles to provide accurate indoor readings, these methods utilize existing wireless infrastructure to determine devices’ locations.
Combining fingerprinting techniques with Combain’s extensive database of wireless access points and Bluetooth beacons can achieve highly accurate positioning.
This overview provides insights into how these systems work, key concepts and terminologies, comparisons of their accuracy, cost estimates for implementations, and recommendations for use cases.
Table of Contents
How WiFi and Bluetooth (BLE) Positioning Work
WiFi Positioning
WiFi positioning involves using the signal strength of WiFi access points (APs) to estimate a device’s location.
Basic Process:
- Data Collection (Fingerprinting): The first step is to conduct a site survey to measure signal strengths (RSSI) from multiple WiFi APs at various known locations. Each measurement forms a “fingerprint.”
- Database Creation: The collected fingerprints are stored in a database like the Combain database, which maps signal strengths to specific locations.
- Position Estimation:A device measures the RSSI from nearby APs and sends this data to the Combain Location API to match it against the fingerprints in the database. Machine learning algorithms or statistical models (e.g., k-Nearest Neighbors or Probabilistic Methods) are used to determine the closest match.
Key Terminologies:
- RSSI (Received Signal Strength Indicator): A measure of signal strength.
- AP (Access Point): A WiFi transmitter.
- Fingerprint: A dataset of RSSI values and corresponding locations.
- Localization Algorithm: The method used to compute the device’s position.
Additional Considerations:
- Time of Arrival (ToA) and Round-Trip-Time (RTT): Advanced techniques like ToA and RTT measure the time it takes for signals to travel between access points and devices. The new WiFi standard 802.11mc supports RTT and can achieve a median error of 1-2 meters, compared to 3-5 meters with RSSI-based methods.
- Indoor Surveys: Indoor surveys are crucial for analyzing the availability and quality of radio signals, such as WiFi and Bluetooth. They also help train positioning algorithms and create heatmaps for signal strength and median errors. For example, a 10×10 meter grid can deliver 3-5 meters of accuracy, while a 20×20 meter grid provides ~7-10 meters of accuracy.
Bluetooth (BLE) Positioning
Bluetooth positioning relies on Bluetooth Low Energy (BLE) beacons, which emit signals that devices can detect and measure.
Basic Process:
- Deployment of Beacons: BLE beacons are strategically placed throughout an area. Each beacon broadcasts a unique identifier.
- Data Collection and Fingerprinting: Like WiFi positioning, signal strengths from BLE beacons are recorded during site surveys and stored in a fingerprint database.
- Position Estimation: Devices detect nearby beacons and measure their RSSI. The Combain Location API provides the device’s position by matching signal strengths with known fingerprints.
Key Terminologies:
- BLE (Bluetooth Low Energy): A wireless technology designed for low power consumption.
- Beacon: A BLE device that transmits identifiers and optional data.
- UUID (Universally Unique Identifier): An identifier broadcast by beacons.
- Proximity Range: Zones (Immediate, Near, Far) defined based on RSSI.
Advanced Techniques:
- Angle of Arrival (AoA): With advanced antenna systems, Bluetooth gateways can calculate the direction of a tracked device. Higher accuracy can be achieved by combining directional data with distance measurements or multiple gateways.
Comparison
| Feature | WiFi Positioning | Bluetooth Positioning |
| Accuracy | ~5-15 meters | ~1-5 meters |
| Infrastructure | Existing WiFi networks | Requires deployment of BLE beacons |
| Setup Costs | Low (uses existing networks) | Moderate to high (additional hardware) |
| Devices | Trackers, Android Phones | Trackers, Android Phones, iOS phones |
| Power Consumption | High (WiFi scanning drains battery) | Low (optimized for low power) |
| Scalability | Excellent (leverages public WiFi APs) | Good (requires beacon management) |
| Reliability | Subject to environmental interference | More reliable in controlled deployments |
| When to use | WiFi positioning is cost-effective for areas with existing dense WiFi networks but has lower accuracy. | Bluetooth positioning offers higher accuracy and reliability but requires upfront investment in BLE infrastructure. |
System Cost Estimates
WiFi Positioning
Example Implementation:
Scenario: Office building with an existing WiFi network (10,000 sq. ft).
- Costs: Site Survey: $2,000 (professional service or internal resources).
- Database Setup and Integration: $5,000 (using Combain’s database and tools).
- Maintenance: $1,000/year (updates to fingerprints).
Total: $7,000 for initial setup + $1,000/year.
Bluetooth (BLE) Positioning
Example Implementation:
Scenario: Retail store chain (5 stores, each 5,000 sq. ft).
- Costs: BLE Beacons: $50 per beacon x 50 beacons per store x 5 stores = $12,500.
- Site Survey: $10,000 (including beacon placement).
- Database Setup and Integration: $7,500.
- Maintenance: $2,500/year (replacing batteries, replacing beacons, updating fingerprints).
Total: $30,000 for initial setup + $2,500/year.
Use Cases
WiFi Positioning
- Large buildings and campuses: Leveraging dense WiFi networks for localization.
- Budget Constraints: Low setup cost makes WiFi ideal for cost-sensitive applications.
- Indoor Navigation: Malls, airports, or office buildings with existing WiFi infrastructure.
Bluetooth (BLE) Positioning
- High-Accuracy Applications: Retail stores for proximity marketing (e.g., sending offers when users approach specific aisles).
- Controlled Environments: Warehouses or manufacturing facilities requiring precise tracking of equipment or goods.
- Asset Tracking: Hospitals tracking medical equipment or ensuring personnel safety in hazardous areas.
Conclusions
WiFi and Bluetooth positioning technologies are effective indoor positioning and tracking tools, each with advantages. WiFi positioning is cost-effective and works well in environments with established networks. In contrast, Bluetooth positioning offers greater accuracy and reliability for controlled deployments. Organizations can create robust, cost-effective positioning systems that enhance operations, improve user experiences, and drive innovation.