Bloom Filter Route Encoding for Map Version Agnostic Navigation

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Solution Overview

Problem

Existing navigation systems face challenges in efficiently communicating route information between devices with different versions of digital maps, leading to bandwidth issues and decoding errors.

Innovation Solution

The use of map version agnostic identifiers encoded into a bloom filter allows for the transmission of route segment sets in a bandwidth-efficient manner, ensuring that the encoded route can be decoded accurately across different map versions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the server maintains multiple versions of the digital map to accommodate different map versions, then the reliability of route decoding is improved, but the device complexity and memory requirements worsen

Engineering Contradiction:
Improveroute decoding accuracyVSAvoidmemory storage requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential route segment identifiers from the full digital map data and encodes them into a compact Bloom filter structure. This allows the server to provide route information without maintaining multiple complete map versions, significantly reducing memory requirements while preserving route decoding accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms route representation from detailed geometric path data to a compact set of segment identifiers encoded in a Bloom filter. This parameter transformation enables efficient storage and transmission while maintaining the ability to accurately decode routes across different map versions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the server transmits detailed route information to ensure accurate decoding, then the reliability of navigation is improved, but the bandwidth consumption worsens

Engineering Contradiction:
Improvenavigation accuracyVSAvoidbandwidth usage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts only the necessary route segment identifiers from complete route data and encodes them into a compact Bloom filter. This extraction reduces transmission bandwidth requirements while maintaining navigation accuracy, as the mobile device can reconstruct the full route using its local map data and the transmitted identifier set.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a compressed representation (Bloom filter) that copies essential route identification information without transmitting the full route geometry. This allows accurate route reconstruction at the mobile device while minimizing server-to-device bandwidth consumption.

Inventive Principle:
Principle #26Copying

3Measurement precision

If the bloom filter size is increased to reduce false positives, then the measurement precision of route identification is improved, but the bandwidth efficiency worsens

Engineering Contradiction:
Improveroute segment identification accuracyVSAvoidtransmission bandwidth
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent optimizes the Bloom filter parameters (size, number of hash functions) to achieve the minimum necessary filter size that provides sufficient precision for route identification. This optimization balances measurement precision with bandwidth efficiency, avoiding both excessive false positives and unnecessary data transmission.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3742122B1Decoding bloom-encoded shortest path routes from known start and target
Publication Date: 2022.08.10 HERE GLOBAL BV
  • EP3742122B1 patent drawingFigure 1
  • EP3742122B1 patent drawingFigure 3

AI summary

A route response is received by a mobile apparatus storing a mobile version of a digital map. The route response includes information identifying starting and target locations of a route and a bloom filter encoding a route segment set defined by the route. Decoded starting and target segments for the route are identified from the mobile version of the digital map based on the information identifying the starting and target locations. Map information is accessed for determining a cost value for segments of the digital map. A segment that satisfies the bloom filter is assigned a minimal cost value. A decoded route from the decoded starting segment to the decoded target segment is determined using a cost minimization route determination algorithm based on the cost value assigned to the segments. The decoded route is provided via a user interface and/or a vehicle is controlled to traverse the decoded route.