Pose Prior : HintPosition

HintPosition helps to reduce the localization search scope in large maps

Overview

HintPosition is a feature that allows you to restrict the localization search scope within large maps, significantly improving both the speed and accuracy of the localization process. By providing a hint position in your localization query, the system will only search within a 25-meter radius of the specified coordinates, which is particularly valuable in environments with visually similar areas.

Key Concepts

• Hint Position: A set of coordinates (x, y, z) that serves as a spatial reference point

• Search Radius: 25 meters around the provided hint position

• Complementary Positioning: Works alongside visual positioning for improved accuracy

Implementation

To pass a hint position in your localization query:

// Add the hint position to your localization query
form.AddField("hintPosition", hintPosition);

// where hintPosition is an (x, y, z) coordinate in the map's Cartesian coordinate system

Integration with Other Positioning Technologies

HintPosition enables powerful hybrid positioning solutions by combining multiset visual positioning with other location technologies:

GPS Integration

• Convert GPS WGS84 coordinates to your map's Cartesian coordinate system

• Implement geo-fencing to determine when users are within mappable areas

• Use the converted coordinates as hint positions for more precise indoor positioning

Bluetooth/WiFi Positioning

• Leverage Bluetooth beacons or WiFi fingerprinting for approximate positioning

• Use these approximate coordinates as hint positions

• Let visual positioning provide the final, high-precision location

Benefits

• Performance Optimization: Significantly reduces computational load by limiting the search area

• Increased Accuracy: Minimizes confusion between visually similar areas in different locations

• Hybrid Positioning: Creates a seamless transition between outdoor (GPS) and indoor positioning

• Resilience: Provides backup positioning when visual features are temporarily obscured or changed

Best Practices

• Update hint positions frequently when users are in motion

• Implement appropriate coordinate system transformations for your specific mapping setup

• Consider the accuracy limitations of your secondary positioning systems when defining search areas

• Validate hint positions before passing them to ensure they fall within valid map boundaries

Example Use Cases

• Multi-floor Navigation: Using floor detection to narrow down the MapSet, then BLE positioning for the hint position

• Campus Navigation: GPS for outdoor areas transitioning to visual positioning for indoor spaces

• Large Warehouse Operations: Using zone-based RF positioning combined with visual positioning for precise inventory placement

Technical Considerations

• Ensure your coordinate systems are properly aligned across positioning technologies

• Consider the latency implications when fusing multiple positioning sources

• Implement appropriate error handling for cases where the hint position may be significantly incorrect