FMCW Radar Crossbar Waveform for Short-Range Target Detection

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Solution Overview

Problem

Conventional FMCW radar devices struggle to accurately detect targets at short distances and high speeds due to the presence of a large DC component, which limits their control distance and detection capability, especially when the interval between vehicles suddenly decreases.

Innovation Solution

The FMCW radar device transmits both triangular and crossbar waveform CW signals, allowing the extraction of speed and angle information from the reflected signals, even in the presence of DC components, using a target detector that processes frequency differences and phase information from in-phase and quadrature channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If FMCW radar device uses conventional triangular waveform transmission, then it can detect targets at normal distances, but it fails to detect targets at short distances and high speeds due to DC component interference

Engineering Contradiction:

Improvetarget detection accuracyVSAvoiddetection capability across different distance and speed ranges

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The radar device dynamically switches between triangular waveform and crossbar waveform transmission modes based on detection needs. The controller selects crossbar waveform when targets are detected at short distances with high speeds to avoid DC component interference, while using triangular waveform for normal detection scenarios.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the waveform parameter of the transmitted signal from conventional triangular waveform to crossbar waveform. This parameter change allows the radar to extract speed information accurately even when targets are close and moving fast, overcoming the DC component limitation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the radar transmits only triangular waveform signals, then the device complexity is low, but the detection capability is limited for short-distance high-speed targets

Engineering Contradiction:

Improvedetection range and speed coverageVSAvoidsignal waveform types

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The radar device achieves multi-functionality by supporting both triangular waveform and crossbar waveform transmission. This allows a single device to handle both normal detection scenarios and special scenarios involving short-distance high-speed targets, eliminating the need for separate detection systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If I/Q channels are not used in the receiver circuit, then the device complexity is reduced, but the sign of frequency cannot be extracted accurately for short-distance high-speed targets

Engineering Contradiction:

Improvefrequency sign extraction accuracyVSAvoidreceiver circuit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention replaces the need for complex I/Q channel receiver circuits with a simplified approach using crossbar waveform transmission. By changing the transmitted signal type, the system can extract frequency sign information without requiring the complex receiver structure that would normally be needed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 detection of approaching targets at short distances and high speeds, preventing collisions by maintaining stability during sudden stops and improving radar detection capabilities beyond conventional limits.

Implementation Method 1

an FMCW radar device which additionally transmits a continuous wave (CW) radar signal to extract accurate speed through a received signal

Methodology Applied

Scientific EffectRadar: Radar

Implementation Method 2

extract speed and angle using a frequency difference between the Tx CW signal and the reflected CW signal

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS9581682B2Frequency modulated continuous wave radar device, and object detection method using continuous wave thereof

Publication Date: 2017.02.28 HL KLEMOVE CORP

AI summary

Disclosed herein is a frequency modulated continuous wave (FMCW) radar device, including: a continuous wave (CW) signal generator configured to generate a transmit (Tx) CW signal; a radio frequency (RF) transmitter configured to transmit the generated Tx CW signal as an RF signal through a Tx antenna; an RF receiver configured to receive a CW signal which is reflected and returned from a forward object after the Tx CW signal is transmitted; a target detector configured to extract speed and angle using a frequency difference between the Tx CW signal and the reflected CW signal, and detect an approaching target; and a detection controller configured to control the RF transmitter to transmit the Tx CW signal as a signal having a triangular waveform in a time-frequency graph and to additionally transmit the Tx CW signal as a signal having a crossbar waveform at a predetermined frequency for a predetermined time, and extract speed and angle from the reflected CW signal having a crossbar waveform so as to detect the approaching target, when the sign of the target speed extracted from the reflected CW signal having a triangular waveform is negative (−).