Radar System Using Spano and Orthogonal Codes
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Solution Overview
Problem
The existing radar system using complementary codes fails to maintain correlation characteristic suppression when phase rotation occurs due to Doppler frequency fluctuations, leading to interference between sector radars.
Innovation Solution
The radar system employs Spano codes and orthogonal codes, where each sector radar generates transmission signals by multiplying Spano codes with orthogonal codes in a predetermined order, ensuring the codes are orthogonal over multiple transmission periods, thereby suppressing interference and maintaining correlation characteristic even with phase rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If complementary codes are used for transmission in multiple sector radars, then interference between sector radars is suppressed, but correlation characteristic deteriorates when phase rotation occurs due to Doppler frequency fluctuations
Solution Approach 1:
The patent changes the code structure from simple complementary codes to a composite code system using Spano codes combined with orthogonal codes. This parameter change in the transmission code structure enables the system to maintain both interference suppression and correlation characteristics even when phase rotation occurs due to Doppler frequency fluctuations.
Solution Approach 2:
The patent creates a composite code structure by combining Spano codes with orthogonal codes. This composite approach integrates the interference suppression capability of Spano codes with the phase rotation robustness of orthogonal codes, resolving the contradiction between interference suppression and correlation maintenance.
2Area of stationary object
If multiple sector radars operate in the same frequency band, then wide angle detection is achieved, but interference between radars increases
Solution Approach 1:
The patent changes the transmission code parameters by using Spano codes with specific autocorrelation properties. This allows multiple sector radars to operate simultaneously in the same frequency band and spatial area while maintaining low interference levels through the unique correlation characteristics of Spano codes.
Data Source
AI summary
Respective sector radars generate first and second transmission signals by multiplying any one Spano code sequence and any one orthogonal code sequence, selected among 2(N+1) first and second Spano code sequences which are different from each other and 2(N+1) first and second orthogonal code sequences which are different from each other, in a predetermined order in each transmission period, where N is an integer of 1 or greater. Respective sector radars convert the first and second transmission signals into first and second high frequency signals, and transmit the first and second high frequency signals through first and second transmission antennas. The 2(N+1) first orthogonal code sequences and the 2(N+1) second orthogonal code sequences used in the respective sector radars are orthogonal over transmission periods of M multiples of 2(N+1), where M is an integer of 2 or greater.