Radar Apparatus Cyclic Shift Code Generation
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Solution Overview
Problem
Conventional radar systems face limitations in increasing the number of transmission radars and enhancing target detection accuracy due to the restricted number of orthogonal codes available for modulation, which hinders the improvement of signal-to-noise ratio and target angle measurement precision.
Innovation Solution
A radar apparatus generates different modulation codes by cyclically shifting the same code sequence with varying cyclic shift amounts, allowing for the creation of distinct transmission signals, and employs a signal processor for frequency domain conversion and code demodulation to enhance target detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If orthogonal codes are used as modulation codes for multiple transmission radars, then code demodulation can be performed to separate transmission signals, but the number of transmission radars is limited by the finite number of available orthogonal codes
Solution Approach 1:
The patent applies parameter changes by introducing cyclic shift amounts as an additional degree of freedom to code sequences. Instead of using only orthogonal codes with fixed structures, the system generates modulation codes by cyclically shifting a base code sequence by different amounts, thereby creating a larger set of distinguishable codes that can be used for more transmission radars
Solution Approach 2:
The patent makes the code sequences dynamic by allowing cyclic shifts of variable amounts. This transforms static orthogonal codes into dynamic code variants that can be adaptively generated for different transmission radars, enabling flexible expansion of the number of transmission radars beyond the limitations of fixed orthogonal code sets
2Measurement precision
If the number of transmission radars is increased to enhance target detection accuracy, then signal-to-noise ratio improves, but integration loss increases when using conventional orthogonal codes
Solution Approach 1:
The patent changes the parameter of code sequence generation by using cyclic shifts instead of conventional orthogonal codes. This parameter change allows for better code differentiation and reduced cross-correlation, which minimizes integration loss while enabling increased numbers of transmission radars for improved target detection accuracy
3Quantity of substance
If cyclic shift amounts are used to generate different modulation codes, then the number of transmission radars can be increased, but code sequences must be carefully designed to maintain low cross-correlation
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing appropriate cyclic shift amounts for different transmission radars before actual signal transmission. This preliminary configuration ensures that when codes are generated, they already have the correct cyclic shift properties to maintain low cross-correlation, enabling systematic expansion of transmission radar numbers while preserving reliability
Data Source
AI summary
Transmission radars (1-nTX) (nTX=1, 2, . . . , NTX) generate mutually different modulation codes Code(nTX, h) by cyclically shifting the same code sequence by mutually different cyclic shift amounts Δτ(nTX), and generate mutually different transmission RF signals (4-nTX) using the mutually different modulation codes Code(nTX, h). As a result, the number of transmission radars 1-nTX can be made larger, and target detection accuracy can be made higher than in a case where orthogonal codes are used as mutually different modulation codes.