Spread spectrum localizers

摘要: A network of localizers determines relative locations in three-dimensional space to within 1 cm by cooperatively measuring propagation times pseudorandom sequences electromagnetic impulses. Ranging transmissions may include encoded digital information increase accuracy. The time is determined from a correlator circuit which provides an analog pseudo-autocorrelation function sampled at discrete bins. has number integrators, each integrator providing signal proportional the integral product expected pulse sequence delayed one bins, and non-delayed received antenna signal. With impulses organized as doublets output can vary considerably shape depending on where autocorrelation peak falls relation nearest bin. Using pattern recognition arrival be much smaller than separation between Because operation standard CMOS circuitry generates noise over large frequency range, only low-noise operates during transmission reception. To provide accuracy necessary for distancing, high-frequency clock inter-localizer communications. uses phase-lock loop rate programmable delay still finer graduations. stage low-frequency receptions, other times.