LORAM 2004: Evaluation and analysis of CARABAS-II and LORA data

Authors:

  • Ulander Lars M H
  • Lundberg Mikael
  • Gustavsson Anders
  • Murdin Daniel
  • Blom Martin
  • Flood Björn
  • Follo Peter
  • Frölind Per-Olov
  • Jonsson Tommy
  • Stenström Gunnar

Publish date: 2005-01-01

Report number: FOI-R--1790--SE

Pages: 64

Written in: English

Abstract

The LORAM 2004 data collection was successfully conducted during September and October 2004. The main experiment site was the Army training area Kvarn located close to Linköping in southern Sweden. The target deployments consisted of both stationary and moving vehicle targets of varying sizes and under varying foliage concealment. This report presents results and analysis of the data collected over Kvarn by FOI using the two airborne low-frequency radars CARABAS-II (20-90 MHz) and LORA (200-800 MHz). Both CARABAS-II and LORA include a synthetic aperture radar (SAR) mode producing high-resolution radar images of stationary targets, whereas only LORA includes a ground moving targets indication (GMTI) mode for detection of moving targets. 11 missionswith 95 flight tracks were flown using CARABAS-II, and 6 missions with 56 passes using LORA. Results from CARABAS-II provide an extensive data base for detection evaluation in conditions typical of southern Sweden. Image resolution and system noise level are nominal. An evaluation of change detection also shows good performance curves, with gradually degraded performance for increasing incidence angles. The detection results are slightly degraded compared to earlier analysis from RFN Vidsel in northern Sweden, mainly due to the higher forest stem volume experienced in southern Sweden. Results from LORA show nominal image focus but a 15 dB higher system noise level than expected. Detection performance has therefore not been evaluated. The cause of the excessive noise has been identified and new flights are planned over similar deployments to enable detection performance evaluation with nominal system noise level.