Spread spectrum localizers
US6400754B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2000 |
| Grant date | Jun 4, 2002 |
| Priority date | — |
| Expiry date | Dec 7, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/709
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A network of localizers determines relative locations in three-dimensional space to within 1 cm by measuring propagation times of pseudorandom sequences of electromagnetic impulses. The propagation time is determined from a correlator which provides an analog pseudo-autocorrelation function sampled at discrete time bins. The correlator has a number of integrators, each integrator providing a signal proportional to the time integral of the product of the expected pulse sequence delayed by one of the discrete time bins, and the non-delayed received antenna signal. Using pattern recognition the arrival time of the received signal can be determined to within a time much smaller than the separation between bins. Because operation of standard CMOS circuitry generates noise over a large frequency range, only low-noise circuitry operates during transmission and reception. A stage in the low-frequency clock uses low-noise circuitry during transmissions and receptions, and standard circuitry at other times.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.