Interferometric modification of the Lockheed Martin PSTAR system to facilitate three dimensional airspace surveillance

Abstract

The Lockheed Martin PSTAR is a monostatic radar system that provides range, azimuth, and radial velocity information of detected targets. While this system is useful for airspace surveillance in remote locations due to its portability and durability, it lacks the ability to record target information and the ability to estimate target elevation angle, resulting in a vertical arc of possible target locations. Due to a desire to use the PSTAR for applications that require logging three-dimensional target information, a spatial interferometric modification has been implemented. The PSTAR estimates range from pulse propagation delay and azimuth angle from the orientation of the antenna on a rotating pedestal. Two PSTAR antennas were removed from their housings and mounted, vertically separated, in a custom enclosure allowing for the estimation of elevation angle through spatial interferometry. The reflected signal is received by both antennas, mixed to baseband, and then the two pairs of I/Q channels are simultaneously sampled at 1 MS/s. Target elevation angle is estimated by determining the phase difference of the target's reflection received by the two vertically spaced antennas. Range, azimuth, and radial velocity are also estimated. All data collection was implemented in LabVIEW and data post-processing was implemented in MATLAB.