UWB Impulse Radar Characterization and Processing Techniques
Abstract
Ultra-Wideband (UWB) impulse radar is inherently a noise-limited technology. While sub-nanosecond pulses achieve good range resolution, the resultant extreme bandwidth exacts a toll on system performance in terms of noise power entering the receiver. Data must be processed efficiently to yield an acceptable signal to noise ratio (SNR), and to enhance structural details of the return pulse. This is achieved by a combination of ensemble averaging to reduce thermal fluctuations and the newly developed Background Noise Conditioning (BNC) method, a statistical signal processing technique used to remove isolated spectral interferers. BNC, developed at DRDC Ottawa, periodically examines spectral noise properties to automatically configure an appropriate notch filter. For the radar data obtained in this investigation, averaging over a relatively small number of pulses is insufficient to raise the desired returns appreciably above the noise floor. Typical SNR values for one received pulse are around 18 to 19 dB. Beyond ten pulses, SNR improves approximately linearly. Integration of about 80 pulses results in a SNR maximum of about 35 dB, with an associated improvement of ^15 dB over the untreated data (that is, for situations where BNC is not applied). For pulses > 80, the averaging takes place over a long enough time period that returns become blurred due to target motion. This effectively defines the upper limit of pulse returns that can be averaged without additional processing to focus the returns. Part of this report is devoted to modeling and characterizing the impulse shape and its associated spectrum. As well, the minimum detectable target velocity is extracted from data and compared with theory, showing good agreement. Wall effects have been investigated-there was an experimental determination of approximately 8dB attenuation losses due to a cindercrete wall. The same wall, once soaked with water, caused only an addmeasur
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2004
- Accession Number
- ADA437380
Entities
People
- Greg Barrie
Organizations
- Defence Research and Development Canada