UAV Audio Video Synchronization Using GPS Time-Stamp Encoding

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Solution Overview

Problem

Existing methods for synchronizing audio and video recordings, especially in remote or airborne applications, face inaccuracies due to imprecise onboard clocking crystals and unreliable wireless communication, leading to potential desynchronization of audio and video tracks during post-processing.

Innovation Solution

A method and system that utilize a GPS receiver on an unmanned aerial vehicle (UAV) to generate precise time-stamp information, which is encoded onto both audio and video recordings, ensuring synchronization by using a real-time clock and video encoder to merge the tracks with an absolute time reference, and a synchronization sound is generated to align audio and video tracks during recording.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If onboard clocking crystals are used for time synchronization, then device complexity is reduced, but time synchronization precision deteriorates

Engineering Contradiction:

Improvesynchronization system complexityVSAvoidtime synchronization precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces GPS satellite signals as an intermediary time reference source. Instead of relying on the UAV's onboard clocking crystal, the system uses GPS time signals received from satellites as a mediator to synchronize both audio and video recordings, achieving high precision without increasing onboard device complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/quartz-based onboard clocking crystal with an electromagnetic-based GPS time signal reception system. This substitution eliminates the limitations of crystal oscillator precision while maintaining system simplicity through external signal utilization

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If wireless communication is used for data transfer, then ease of operation is improved, but reliability of synchronization deteriorates

Engineering Contradiction:

Improvedata transfer convenienceVSAvoidsynchronization reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by embedding time stamp information directly into the audio and video data streams during the recording process itself. This ensures that synchronization data is captured at the source with high reliability, eliminating dependence on post-processing wireless communication for synchronization purposes

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system segments the synchronization function into independent time stamp generation and embedding components. Each recording device (audio and video) independently receives GPS time signals and embeds its own time stamps, allowing reliable synchronization without requiring continuous wireless communication between devices

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If GPS time-stamp encoding is implemented, then time synchronization precision is improved, but device complexity increases

Engineering Contradiction:

Improvetime synchronization precisionVSAvoidencoding system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the GPS receiver perform multiple functions: it serves as both the primary navigation/time source for the UAV and the synchronization time reference for audio-video recording. This multi-functionality achieves high precision synchronization without adding dedicated encoding hardware, thus limiting complexity increase

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides accurate and reliable synchronization of audio and video tracks, even in remote or airborne scenarios, by using GPS time-stamp information and a synchronization sound, ensuring seamless integration during post-processing and reducing the likelihood of lip-sync issues.

Implementation Method 1

using a GPS to generate location data and a GPS time-stamp, based on satellite triangulation and a system-wide GPS clock signal

Methodology Applied

Scientific EffectGPS satellite triangulation and clock signal:

Data Source

PatentUS10535372B2System for recording and synchronizing audio and video associated with a UAV flight

Publication Date: 2020.01.14 VANTAGE ROBOTICS LLC

AI summary

A method for synchronizing an audio track that is being recorded at a first location with a video track that is being recorded at a second location, such as on a flying UAV, is disclosed. First, the audio and video recorders being to record sound and video. Then, a GPS receive is used to pick up the very accurate GPS clock signal. A real-time clock is also used locally to generate a real-time value. At a predetermined time, the GPS time data is interrogated and a time-stamp is generated. A video encoder is then used to embed the time-stamp, either during recording, or shortly thereafter. A networked audio recording device records audio with a time stamp acquired from the network. These respective time-stamps are then used in post-processing to accurately synchronize the audio and video tracks.