Coherently combining antennas using pseudo-random calibration

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Solution Overview

Problem

The challenge in coherently combining multiple high gain antennas is achieving the necessary time delay and phase compensation, especially for wide bandwidth signals, while also ensuring proper alignment and diagnostics, as existing methods are inefficient and prone to interference.

Innovation Solution

A wide bandwidth pseudo-random calibration code is transmitted to determine time delays and compensate for phase imperfections among antenna elements, allowing for efficient coherent combination, diagnostics, and alignment through built-in test equipment capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single high gain antenna is used to improve receiving capability, then antenna gain is improved, but cost and complexity increase

Engineering Contradiction:

Improvereceiving capabilityVSAvoidantenna system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides a single high gain antenna into multiple smaller antenna elements that can be coherently combined. Instead of using one large complex antenna, the system uses N smaller antenna elements whose signals are processed and combined to achieve equivalent or superior receiving capability with reduced individual element complexity and cost.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines signals from multiple antenna elements through coherent combination at the receiver. By merging the outputs of N antenna elements with proper phase and amplitude alignment, the system achieves the equivalent receiving capability of a single high gain antenna while distributing the physical and computational complexity across multiple simpler components.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple antenna elements are coherently combined to achieve high gain, then receiving capability is improved, but time delay and phase compensation requirements increase system complexity

Engineering Contradiction:

Improvereceiving capabilityVSAvoidsignal processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or electronic phase shifters with digital signal processing for time delay and phase compensation. Instead of using analog devices to adjust phases, the system uses digital correlation processing with pseudo-random codes to achieve coherent combination, simplifying the hardware while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the coherent combination problem from the time domain to the frequency domain through correlation processing. By using pseudo-random codes and correlation techniques, the system efficiently handles time delay and phase compensation across wide bandwidth signals, converting a complex multi-parameter adjustment problem into a more manageable correlation measurement task.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If wide bandwidth signals are processed through multiple antenna elements, then receiving capability is improved, but tolerance requirements for time delay and phase compensation become more stringent

Engineering Contradiction:

Improvereceiving capabilityVSAvoidtime delay and phase tolerance

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent implements dynamic time delay adjustment for each antenna element based on measured signal characteristics. Rather than using fixed delay values, the system continuously measures arrival time differences using pseudo-random code correlation and dynamically adjusts delays to maintain optimal coherent combination across varying signal conditions and wide bandwidths.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses feedback from correlation measurements to iteratively optimize time delay and phase compensation parameters. The system measures the correlation output from each antenna element, uses this feedback to adjust delay settings, and repeats the process to achieve optimal coherent combination, thereby adapting to wide bandwidth requirements without stringent fixed tolerances.

Inventive Principle:

Principle #23Feedback

4Reliability

If coherent combination of antenna elements is implemented, then receiving capability is improved, but susceptibility to local interfering signals increases

Engineering Contradiction:

Improvereceiving capabilityVSAvoidinterference susceptibility

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses pseudo-random codes as an intermediary to enable coherent combination while rejecting interference. By modulating antenna element outputs with unique pseudo-random codes and correlating with the known code at the receiver, the system achieves signal enhancement through coherent combination while local interferers without the correct code correlation are naturally rejected, providing interference immunity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7602336B2Coherently combining antennas

Publication Date: 2009.10.13 AEROSPACE CORP

AI summary

An apparatus includes antenna elements configured to receive a signal including pseudo-random code, and electronics configured to use the pseudo-random code to determine time delays of signals incident upon the antenna elements and to compensate the signals to coherently combine the antenna elements.