Vehicle Radar Speed Unambiguity via Segmented FMFSK Sequences
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Solution Overview
Problem
Existing vehicle radar devices using frequency-modulated frequency shift keying (FMFSK) face ambiguities in speed measurement at high relative speeds, and reducing sampling time to improve speed resolution either deteriorates measurement quality or requires expensive hardware.
Innovation Solution
The method involves transmitting sequences 1A and 2A, 2B, and combining them for evaluation using Fourier transformations, where only every second signal A is used in the combined sequence 1A-2A to achieve sufficient speed unambiguity and improved resolution without requiring more expensive hardware, allowing for quick speed estimation and aliasing effect checking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If sampling time is reduced to increase maximum unambiguous speed, then speed measurement range is improved, but measurement time is reduced leading to deteriorated speed resolution
Solution Approach 1:
The measurement process is divided into two separate measurement periods: a first measurement period for speed estimation and a second measurement period for refined speed measurement and distance determination. This segmentation allows each period to be optimized for its specific purpose, resolving the contradiction between maximum unambiguous speed and speed resolution.
Solution Approach 2:
Speed estimation is performed in advance during the first measurement period before the second measurement period. This preliminary action provides an initial speed value that guides subsequent processing, allowing the system to achieve both fast response and high resolution without requiring expensive hardware.
2Measurement precision
If measurement time is increased to improve speed resolution, then speed resolution is improved, but measurement time increases reducing productivity
Solution Approach 1:
The measurement process is segmented into two periods with different purposes: the first period provides quick speed estimation, while the second period performs refined measurement. This segmentation enables the system to achieve high speed resolution without requiring excessively long measurement times, thus maintaining measurement throughput.
Solution Approach 2:
By performing speed estimation in the first measurement period before the second period, the system obtains preliminary speed information that facilitates more efficient processing in the second period. This preliminary action reduces the overall time required to achieve high-resolution speed measurement.
3Speed
If sampling time is reduced to increase maximum unambiguous speed, then speed measurement range is improved, but more expensive hardware is required
Solution Approach 1:
The measurement process is divided into two periods: the first period uses a shorter effective sampling interval to achieve high maximum unambiguous speed, while the second period uses the full sampling time for high-resolution measurement. This segmentation allows the system to achieve both high speed range and high resolution using standard hardware, avoiding the need for expensive high-speed components.
Solution Approach 2:
Speed estimation is performed in advance during the first measurement period, providing preliminary information that enables the second period to focus on high-resolution measurement. This preliminary action allows the system to achieve high performance with standard hardware by intelligently distributing measurement tasks across two periods.
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 ensures clear speed measurement at high relative speeds while maintaining speed resolution quality without additional hardware costs, enabling accurate distance determination and reducing the need for costly hardware upgrades.
Implementation Method 1
The present invention relates to an operating method for a vehicle radar device in which frequency modulated frequency shift keying is used
Implementation Method 2
The relative speed and distance of the target object in relation to the vehicle are then determined by evaluating the transmitted and received signals
Data Source
AI summary
The operating method involves alternate emitting a signal with a frequency (f-a) or a frequency profile for a time duration and another signal with another frequency (f-b) or a frequency profile for another time duration during a measuring time duration in the direction of a target object. The former signal is emitted with former frequency or the former frequency profile for the former time duration during another measuring time duration.