A rapid-acquisition architecture for advanced avionics and spread-spectrum applications

A rapid-acquisition architecture for frequency hopping (FH), direct sequence (DS), and various forms of hybrid spread-spectrum waveforms is presented. This concept offers extraordinary improvements in flexibility and adaptability, as well as significant advantages in size, weight, and power reduction over those of conventional systems. The general concept is based on matching application-specific integrated circuit (ASIC) variable-length digital matched filter technology to programmable digital frequency synthesizers for an adaptable -FH/DS spread-spectrum system. Within a given time interval a specific set of outputs from each code-matched filter (CMF) appears which represents the correlation of the received signal against a certain code offset. This is the key function for fast and reliable acquisition of the spread-spectrum signals. The basic configuration consists of the fast-acquisition subsystem, which receives the signals and downconverts, or dehops, by a frequency-hopping local oscillator driven by the known pseudonoise frequency hop pattern. This architecture configuration offers ease of technology insertion as new developments in technology may emerge. The modular philosophy allows for future expansion of the initial architecture in a cost-effective manner