SABER-TDA: Passive coherent location of aircraft using XM-Radio and a small ground station

Abstract

This paper reports on early observation results from the S-band Array for Bistatic Electromagnetic Ranging Technology Demonstrator Array. This system is a demonstration platform for a passive ground-based primary radar station for monitoring aircraft. This station is unique in that it utilizes existing satellite-based radio signals as transmitters rather than terrestrial signals. Using algorithms that enable long integration times, this system might provide accurate position and velocity measurements at ranges of tens of nautical miles from the ground station for most targets, and up to 100 nautical miles for larger targets. In these measurements, XM-Radio was used as the illuminator and the SABER-TDA station as the receiver. Different types of aircraft were observed in different scattering geometries. Comparison with truth data is in progress.

Basic tracking using nonlinear 3D monostatic and bistatic measurements

“…This transformation can be derived by substituting in the cumulative distribution function (CDF) of the r-u-v measurement and then by evaluating the derivative to get the PDF. The Jacobian matrix is defined to be the matrix of gradient vectors (26) For the problem at hand, using (21), the gradient vectors are (27) (28)…”

“…The conversion between a radar's local Cartesian coordinate system and the global Cartesian coordinate system involves an affine transformation. 21 A measurement in global Cartesian coordinates can be converted to and from local Cartesian coordinates as…”

“…The rotation of the Earth affects the apparent direction of the vertical for an observer on the surface. 29 For example, satellite radio provides a sufficiently strong signal; it was successfully used for passive detection with off-the-shelf hardware [21]. The power of the direct-path signal from such satellites is on the order of 10−14 W/m2, and even small, portable receivers are able to pick it up [4].…”

“…By definition, the first two moments are given as 45 (86) (87) where is the conversion given in (21). As discussed in Section III, the best techniques for evaluating these moments involve forms of numerical integration.…”

A signal processing scheme for a multichannel passive radar system

“…Passive radar is a reemerging technology area that has received much attention in the academic and defence sectors in the past decade [1,2,3,4,5,6]. Whilst passive radar has a number of strengths and weaknesses with respect to cooperative and active monostatic radar, it is the author's opinion that the recent resurgence in interest is primarily due to three dominant factors: 1) Spectrum congestion and diminishing allocation for active radar has motivated the search for viable alternatives; 2) Improvements in technology have overcome some historical limitations (computational complexity and synchronisation issues to name two); and 3) the transmitters typically considered most suitable from an exploitation standpoint (namely broadcast television and radio) have seen a change in their modulation structures from analogue to digital; this has greatly simplified the necessary processing, and improved system performance, reliability and resolution.…”