Orthogonal Separation Device Phase Adjustment MIMO Radar

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Solution Overview

Problem

The time separation system in MIMO radar limits the measurable speed of targets due to increased time intervals between signals from multiple antennas, leading to decreased frequency of observable signals and difficulty in detecting high-speed targets.

Innovation Solution

An orthogonal separation method where pulse waves are not multiplexed on the frequency or time axis, but instead set as arrays of discrete values with different phases, allowing for phase adjustments at the reception end to separate signals through M × N transfer paths between multiple antennas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the time separation system is used to distinguish signals from multiple transmitting antennas, then the number of antennas can be increased, but the measurable speed of targets is limited due to increased time intervals between signals

Engineering Contradiction:
Improvenumber of antennasVSAvoidmeasurable speed of target
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The patent changes the separation parameter from time domain to phase domain. By assigning different phase codes to signals from different transmitting antennas and using phase adjustment at the reception end, the system maintains high sampling frequency while supporting multiple antennas, thus resolving the speed limitation caused by time separation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the time interval between signals from individual transmitting antennas is increased to accommodate more antennas, then the number of antennas can be increased, but the frequency of observable received signal is decreased

Engineering Contradiction:
Improvenumber of transmitting antennasVSAvoidfrequency of observable signal
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent transforms the signal separation approach from time-based to phase-based. By using phase codes and phase adjustment, the system allows simultaneous transmission from multiple antennas without increasing time intervals, thereby maintaining high observable signal frequency and measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the time interval of sampling is increased to distinguish signals from more transmitting antennas, then signal distinction is improved, but the upper limit of measurable speed is decreased

Engineering Contradiction:
Improvesignal distinction capabilityVSAvoidupper limit of measurable speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent changes the separation dimension from time to phase. By encoding signals with different phase codes and using phase adjustment at reception, the system achieves reliable signal distinction without increasing sampling time interval, thus maintaining high measurable speed upper limit.

Inventive Principle:
Principle #35Parameter changes

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 enables accurate, stable, and cost-effective separation of pulse waves without significant digital signal processing constraints, information loss, or increased reception band requirements, allowing for improved detection of high-speed targets and enhanced azimuth angle resolution.

Implementation Method 1

a phase adjuster that adjusts the difference among the phases of the plural number P of demodulated signals according to the arrays of known discrete values

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentEP3187894B1Orthogonal separation device and orthogonal separation method
Publication Date: 2021.06.09 JAPAN RADIO CO LTD
  • EP3187894B1 patent drawingFigure 1
  • EP3187894B1 patent drawingFigure 2
  • EP3187894B1 patent drawingFigure 3

AI summary

An orthogonal separation device of the invention includes a demodulator that performs a demodulation process corresponding to each of a plural number N of antennas for each of a plural number P (=M × N) of pulse waves (R11 to R1M), ..., (RN1 to RNM) which arrives at the plural number N of antennas by transmitting, at the same time, a plural number M of pulse waves having phases φ1 to φM set as different arrays of known discrete values and that generates a plural number P of demodulated signals (R'11 to R'1M), ..., (R'N1 to R'NM), and includes a phase adjuster that adjusts difference among the phases of a plural number P of demodulated signals (R'11 to R'1M), ..., (R'N1 to R'NM) according to the arrays of known discrete values and generates a plural number P of in-phase signals (r11 to r1M), ..., (rN1 to rNM).