Vehicular Radar Self-Interference Cancellation
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Solution Overview
Problem
Current radar systems face challenges in achieving good range performance without excessive transmitter power and in efficiently sharing frequency spectra, while also requiring improved tradeoffs between instantaneous bandwidth occupancy and range resolution.
Innovation Solution
The implementation of an FMCW radar system with constant envelope transmitters that use frequency modulation with smoothly shaped frequency deviation pulses, optimized for low cross-correlation codes and efficient memory organization to reduce spectral density and enhance target discrimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmitter power is increased to improve range performance, then range resolution is improved, but transmitter power consumption increases excessively
Solution Approach 1:
The patent changes the frequency modulation parameters by using smoothly shaped frequency deviation pulses instead of traditional linear chirps. This parameter change allows the system to achieve good range resolution through optimized frequency transition shapes while maintaining constant envelope power, thereby improving range performance without excessively increasing transmitter power.
Solution Approach 2:
The patent employs dynamic frequency modulation where the frequency deviation is smoothly shaped rather than linear. This dynamic approach allows adaptive control of the frequency transitions to optimize the tradeoff between range resolution and power consumption, enabling the system to achieve clear target discrimination without excessive power usage.
2Measurement precision
If frequency modulation bandwidth is increased to improve range resolution, then range resolution is improved, but instantaneous bandwidth occupancy increases
Solution Approach 1:
The patent optimizes the frequency modulation parameters by using smoothly shaped frequency deviation pulses with controlled bandwidth. This parameter optimization allows the system to achieve good range resolution through careful design of the frequency transition characteristics, thereby improving range resolution while controlling instantaneous bandwidth occupancy to enable efficient spectrum sharing.
3Productivity
If multiple users share the frequency spectrum, then spectrum efficiency is improved, but interference between users increases
Solution Approach 1:
The patent uses smoothly shaped frequency deviation pulses that optimize the spectral characteristics of the transmitted signal. This parameter change reduces spectral leakage and interference between multiple users sharing the frequency spectrum, thereby improving spectrum efficiency while minimizing harmful interference through optimized frequency modulation characteristics.
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 efficient range resolution and target detection with reduced transmitter power, allowing for multiple users to share the spectrum effectively and improving the tradeoff between bandwidth occupancy and range resolution.
Implementation Method 1
The frequency modulation uses codes to deviate the frequency from a mean or center frequency according to one of a limited number of shaped frequency transitions
Implementation Method 2
A radar system typically transmits a signal and listens for the reflection of the signal from objects in the environment
Implementation Method 3
Mixing (multiplying) a waveform reflected from an object (also known as a target) with a replica of the transmitted signal results in a CW signal with a frequency that represents the distance
Implementation Method 4
Each transmitter comprises a frequency generator, a code generator, a modulator, a constant-envelop power amplifier, and an antenna
Data Source
AI summary
A radar system is described that comprises a transmitter and a receiver. The transmitter transmits radio signals. The receiver receives interfering signals due to local signal coupling of transmitted signals. The local signal coupling comprises at least one interfering path or mechanism. The receiver is configured to output a replica of each of the interfering signals. Each replica is configured to replicate a particular interfering signal received. The receiver is configured to combine into a signal path a replica of an interfering signal to subtract the interfering signal from the signal path. The receiver receives the transmitted radio signals transmitted by the transmitter and reflected from objects in an environment without saturating the signal path due to the subtraction of the interfering signal from the signal path.