Biphase Barker-Coded Data Transmission Recommended Techniques for CAS

The use of biphase modulation and Barker data coding within the 200-us range/Doppler transmission proposed for collision avoidance systems (CAS) is described. Following a general discussion of requirements for compatibility between important CAS threat-evaluation measurements and less essential message communications, emphasis is placed on consideration of the binary Barker pulse sequences and the recommended biphase modulation techniques for data transmission.