Doppler synthetic aperture radar interferometry: a novel SAR interferometry for height mapping using ultra-narrowband waveforms

Abstract

This paper introduces a new and novel radar interferometry based on Doppler synthetic aperture radar (Doppler-SAR) paradigm. Conventional SAR interferometry relies on wideband transmitted waveforms to obtain high range resolution. Topography of a surface is directly related to the range difference between two antennas configured at different positions. Doppler-SAR is a novel imaging modality that uses ultra-narrowband continuous waves (UNCW). It takes advantage of high resolution Doppler information provided by UNCWs to form high resolution SAR images.We introduced the theory of Doppler-SAR interferometry.We derived interferometric phase model and develop the equations of height mapping. Unlike conventional SAR interferometry, we show that the topography of a scene is related to the difference in Doppler between two antennas configured at different velocities. While the conventional SAR interferometry uses range, Doppler and Doppler due to interferometric phase in height mapping, Doppler-SAR interferometry uses Doppler, Doppler-rate and Doppler-rate due to interferometric phase in height mapping. We demonstrate our theory in numerical simulations.Doppler-SAR interferometry offers the advantages of long-range, robust, environmentally friendly operations; low-power, low-cost, lightweight systems suitable for low-payload platforms, such as micro-satellites; and passive applications using sources of opportunity transmitting UNCW.

Round Trip Time (RTT) and Doppler Measurements for IoRT Localization by a Single-Satellite

“…To the best of the authors' knowledge, the integration of RTT and Doppler measurements for satellite-side localization of outdoor terrestrial terminals has not been considered in the literature. Our approach draws inspiration from the principles employed in Synthetic Aperture Radars (SARs) which rely on the intersection of the Doppler cone, ranging sphere, and Earth surface for positioning the target [7]. However, in our approach, we involve RTT ellipsoid, Doppler cone, and Earth spheroid to aid the positioning.…”

Windowing Accuracy Evaluation for PSLR Enhancement of SAR Image Recovery

“…In this mode, the electromagnetic energy is transmitted and its associated radar beam is used to illuminate a specified area that is called footprint. The radar antenna is pointed along a fixed direction according to the flight path, and the antenna footprint covers a strip on the illuminated surface of a point target [6][7][8]. The length of the strip is limited by the distance to which the sensor moves through the travel.…”

A mathematical perspective on radar interferometry

“…In reality, however, the antenna location accuracy is orders of magnitude worse. Previous publications on extending the mathematical approach from plain SAR imaging to radar interferometry include [7,39,40]. In this work, we aim at addressing the issues that may still require attention.…”