FMCW Radar Cycle Time Reduction via Previous Cycle Signal Comparison

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current FMCW radar sensors require longer cycle times for measurement cycles, which limits temporal resolution in safety-relevant applications and necessitates more expensive processors, as the duration of the modulation pattern cannot be shortened without compromising measurement accuracy.

Innovation Solution

The method involves comparing signals from the current measurement cycle with those from previous cycles, utilizing the inertia of vehicles to minimize speed changes, thereby reducing the cycle time by using data from earlier cycles for adjustment, allowing for shorter cycle times and more affordable processors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the modulation pattern duration is extended to improve measurement accuracy, then measurement precision is improved, but cycle time increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcycle time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by using speed information from previous measurement cycles to pre-correct distance measurements in the current cycle. By anticipating that speed changes are minimal due to vehicle inertia, the system prepares correction values in advance from historical data, allowing the current measurement cycle to be shortened while maintaining accuracy through these pre-computed corrections.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the cycle time is shortened to improve temporal resolution, then productivity is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvetemporal resolutionVSAvoidmeasurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by continuously using measurement results from previous cycles to correct and improve current cycle measurements. The speed information from prior cycles feeds into the current distance calculation process, creating a closed-loop system where historical data enhances present accuracy. This feedback mechanism allows shorter cycle times while maintaining measurement precision through iterative refinement.

Inventive Principle:
Principle #23Feedback

3Productivity

If more powerful processors are used to reduce computing time, then productivity is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecomputing speedVSAvoidprocessor requirements
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies partial action by not requiring complete re-evaluation of all measurement parameters in each cycle. Instead, only specific corrections related to speed-induced distance errors are computed using simplified formulas based on previous cycle data. This partial processing approach reduces the computational burden significantly, allowing standard processors to achieve the required performance without needing expensive high-power hardware.

Inventive Principle:
Principle #16Partial or excessive action

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 reduces the cycle time and error in speed data, enabling higher temporal resolution without increasing computational power, making it suitable for safety-critical applications like adaptive cruise control systems.

Implementation Method 1

each radar object is visible in the frequency spectrum of the baseband signal in the form of a peak, the position of which depends on the Doppler shift and the propagation time of the radar signals

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP2755045B1Method for the cyclic measuring of distances and speeds of objects with an FMCW radar sensor
Publication Date: 2016.09.28 ROBERT BOSCH GMBH
  • EP2755045B1 patent drawingFigure 1~2
  • EP2755045B1 patent drawingFigure 3~4
  • EP2755045B1 patent drawingFigure 5~6

AI summary

1. A method for the cyclical measurement of distances (d) and relative velocities (v) of objects using an FMCW radar sensor, wherein a transmitted signal of the radar sensor is periodically modulated in its frequency (f), each period (P) containing at least two different modulation patterns (M1, M2, M3), a relationship between distance (d) and velocity (v) of the object is derived from a signal received for a single modulation pattern, and the signals contained for several modulation patterns are compared with each other in order to determine a value for the distance and velocity in each measurement cycle, characterized in that, for the comparison of the signal received for a modulation pattern (M1) in the current measurement cycle (Z1) with the signal(s) received for other modulation patterns (M1, M2), the signals from at least one previous measurement cycle (Z2, Z3) are used.