Robust Target Acquisition using Consecutive Range Doppler Maps
Abstract
The computation of Range Doppler Maps (RDMs) is a natural step during the creation of SAR (or DBS) images. While the antenna footprint passes over a scenario the continuous data stream is split into packages that contain a fixed number of pulses which undergo the necessary Doppler treatment to achieve cross-range resolution. The outcome is a series of consecutive RDMs that have to be projected to a grid on the ground to create the final combined SAR ground map. This can either be the usual multi-look map which results from incoherent averaging of all signals within each resolution cell of the ground grid. It can also be a "single-look complex" (SLC) map in which case only one signal per resolution cell must be retained depending on a certain criterion (e.g. maximum total backscatter power). The RDMs by their nature are SLC. However, their size corresponds only to the antenna footprint (or, rather, the Doppler unambiguous range) and therefore comprises only a small portion of the scenario, moreover they need not to be projected to a ground grid. For a reconnaissance drone or a seeker that makes use of the SAR/DBS principle, it is a natural thing to use consecutive RDMs instead of projected ground maps. The main reasons are that the ATR algorithm should work in real time, and that the requirements for motion compensation are less stringent. Creating projected maps using flight attitude data of insufficient precision may introduce a loss of effective resolution and a blurring of the target images.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2005
- Accession Number
- ADA471176
Entities
People
- Hartmut Schimpf
- Johann Billner