Coherent DAR Beam Steering Delay for Time-of-Flight Recovery

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Solution Overview

Problem

Existing detection and ranging (DAR) systems face challenges in managing time of flight information, particularly for longest-range targets, which incur significant time-of-flight loss and stringent link budgets, leading to inefficiencies in coherent processing.

Innovation Solution

A DAR system is configured to delay the steering of the receiver relative to the transmitter using optical phased arrays, allowing for time-division-multiplexed local oscillator switching and chirped signals to recover time-of-flight information, thereby reducing time-of-flight loss for longest-range targets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the receiver steering is delayed relative to the transmitter to account for time of flight, then time-of-flight loss for longest-range targets is reduced, but the system complexity increases due to synchronized timing control of multiple optical beam steering modules

Engineering Contradiction:

Improvetime-of-flight lossVSAvoidtiming control complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The receiver steering is delayed relative to the transmitter steering by a predetermined time interval corresponding to the maximum target range. This preliminary timing arrangement ensures that when the transmitter steers to a new angular position, the receiver is already positioned to receive the backscattered signal after the round-trip time of flight, thereby recovering time-of-flight loss for longest-range targets without requiring complex real-time synchronization

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the steering timing of multiple optical beam steering modules based on the maximum target range. The transmitter and receiver modules operate with a fixed time offset that allows the receiver to capture signals from the furthest targets, enabling adaptive timing control that optimizes performance across varying target distances while maintaining manageable system complexity

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If time-division-multiplexed local oscillator switching is used to recover time-of-flight information, then measurement precision is improved, but the device complexity increases due to additional switching and timing circuitry

Engineering Contradiction:

Improvetime of flight measurement precisionVSAvoidswitching and timing circuitry

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The local oscillator is switched between different angular positions using time-division multiplexing, where each switching cycle corresponds to a specific time interval. This periodic switching allows the system to associate received signals with specific transmit-receive time pairs, enabling precise time-of-flight measurement for longest-range targets while using a systematic approach that manages the complexity of the switching and timing circuitry

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS20260023165A1Managing time of flight information in a coherent detection and ranging system

Publication Date: 2026.01.22 ANALOG PHOTONICS LLC

AI summary

An apparatus comprises: a transmitter module comprising: a first optical beam steering module, and timing circuitry configured to control timing of steering of the first optical beam steering module; and a receiver module comprising: a second optical beam steering module, and timing circuitry configured to control timing of steering of the second optical beam steering module; wherein timing of the steering of the first optical beam steering module and second optical beam steering module are controlled to include a delay based at least in part on a predetermined maximum target range.