Radar Modulation with Linear Frequency Sweeps for High-Resolution Ranging
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Solution Overview
Problem
Existing radar systems for driver assistance in vehicles face challenges in achieving high distance resolution and range with moderate digital signal processing, particularly at high radial relative speeds, leading to reduced sensitivity and separation capability.
Innovation Solution
A radar modulation method involving a sequence of individual signals with linearly changing frequency positions and time intervals, combined with two-dimensional discrete Fourier transforms, allows for high measurement accuracy and resolution in distance and relative speed using affordable signal processors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radar modulation methods are used to achieve high distance resolution and large range, then measurement accuracy is improved, but digital signal processing outlay and cost increase significantly
Solution Approach 1:
The patent changes the modulation parameters by linearly varying both the frequency position and time interval of individual signals over the sequence, with the time interval change being twice as large as the frequency position change. This parameter modification allows achieving high distance resolution while reducing the processing requirements compared to conventional methods.
Solution Approach 2:
The patent introduces an additional dimension to the signal modulation by simultaneously varying both frequency position and time interval, rather than only frequency. This dimensional expansion in the signal space enables better separation capability and distance resolution with moderate processing outlay.
2Measurement precision
If conventional radar modulation methods are used to achieve high distance resolution, then separation capability is improved, but signal processing complexity and power consumption increase
Solution Approach 1:
By modifying the modulation parameters to include linear changes in both frequency position and time interval, the patent achieves improved separation capability while reducing the computational complexity of signal processing, thereby lowering power consumption in the processor.
3Measurement precision
If conventional radar modulation methods are used, then distance resolution is improved, but measurement accuracy at high radial relative speed deteriorates
Solution Approach 1:
The patent compensates for the Doppler effect at high radial relative speeds by incorporating linear changes in both frequency position and time interval. This dual parameter modulation maintains measurement accuracy across a wider range of relative speeds compared to conventional methods.
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
Enables simultaneous large range and high distance resolution with less expensive signal processors, improving separation capability and reducing power consumption while maintaining accuracy at high relative speeds.
Implementation Method 1
Over the sequence of the individual signals, the frequency position thereof (which is in particular characterized by the center frequency thereof) and the time interval thereof are at least approximately linearly changed
Implementation Method 2
A radar modulation method involving a sequence of individual signals with linearly changing frequency positions and time intervals, combined with two-dimensional discrete Fourier transforms, allows for high measurement accuracy and resolution in distance and relative speed
Data Source
AI summary
A method of controlling a radar system is presented, for detecting the surroundings using transmission means for emitting transmission signals which contain a sequence of at least approximately identical individual signals, the sequence of individual transmission signals being repeated cyclically, said method being characterized in that over the sequence of the individual signals the frequency position thereof—optionally apart from a varying and at least approximately mean value-free component—is changed at least approximately linearly and, in the process, the slope of the linear frequency position change over the individual transmission signals is at least sometimes varied from sequence to sequence, in particular in order to increase the radial distance and/or relative speed measurement accuracy and/or in order to be more robust in respect of interference with other radar systems.