Inverse fast fourier transform (IFFT) with overlap and add
US7197095B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 2004 |
| Grant date | Mar 27, 2007 |
| Priority date | — |
| Expiry date | Dec 1, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04K3/228
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for efficiently filtering interfering signals in a front end of a GPS receiver is disclosed. Such interfering signals can emanate from friendly, as well as unfriendly, sources. One embodiment includes a GPS receiver with a space-time adaptive processing (STAP) filter. At least a portion of the interfering signals are removed by applying weights to the inputs. One embodiment adaptively calculates and applies the weights by Fourier Transform convolution and Fourier Transform correlation. The Fourier Transform can be computed via a Fast Fourier Transform (FFT). This approach advantageously reduces computational complexity to practical levels. Another embodiment utilizes redundancy in the covariance matrix to further reduce computational complexity. In another embodiment, an improved FFT and an improved Inverse FFT further reduce computational complexity and improve speed. Advantageously, embodiments can efficiently null a relatively large number of jammers at a relatively low cost and with relatively low operating power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.