Project IceSAR Andrew Brownfield Cameron Chapman Nicholas Mans Jon Wehling Objective Build and test a Synthetic Aperture Endfire Array Radar in order to reconstruct 3D image of the terrain in front of the spacecraft. Enceladus (moon of Saturn) Mean radius 252.1 ± 0.1 km (0.0395 Earths) Mass (1.080 22 ± 0.001 01) × 1020 kg (1.8×10-5 Earths) Surface temp. Kelvin Average: 75K Max: 145K Subterranean Oceans Fissures Ice Geysers Project VALKYRIE (Very-Deep Autonomous Laser-Powered Kilowatt-Class Yo-Yoing Robotic Ice Explorer) NASA’s Request For Proposals VALKYRIE – collaborations between Stone Aerospace and Professor Gasiewski Request for prototype to Antarctica From there the design goes to Enceladus VALKALRIE’s obstacle avoidance Radar driven obstacle avoidance • • Use radar to see rocks through ice – 500MHz needed Space issues – Patch or dipole antenna Patch Antenna Radiation Dipole Antenna Radiation Accurate object detection requires sufficient resolution, either through a scanning focused beam or by utilizing SAR to synthetically narrow the beam Synthetic Aperture Radar (SAR) • Using the Range Gating Principle it is possible to calculate the distance to an object • The magnitude and phase of the return signal at multiple positions allows for the reconstruction of a radar image and relative position of the object in 3D space http://www.rfcafe.com/references/electrical/NEETS%20Modules/NEETS-Module-11-3-1-3-10.htm Synthetic Aperture Radar (cont.) • A single broad radar pulse will provide general distance information, but no direction, due to azimuthal ambiguity • Multiple pulses from different locations provide a tool for determining direction, thus effectively narrowing the beam width • By sampling many times in a flyby plane or satellite, one can sweep out large tracts of information, with each point on the ground generated with many different radar pulses. www.skylondaworks.com/sc_sar0.htm VALKYRIE’s SAR • Probe moves towards the objects it’s detecting, not orthogonal to it • Complex algorithms to determine relative position of an object • 4 antennae are not pointed orthogonally or parallel, but tilted and concentrically oriented around the nose of the probe High Level Systems Layout Solid Objects Patch/ Dipole Antenna Array Microwave Isolators Power Management System Transceiver Pulse/Signal Generator Receiver Signal Processing and Correction Data Processing (Matlab) SAR Image Transmitter • 100W transmission power – Sin wave generator (500MHz) – 30ns Pulse (gated switch) – Amplifier Antenna Dipole • Omnidirectional Radiation • Compact • Backplane λ/4 separation to partially direct the beam Microstrip patch • Hemispherical radiation • Backplane next to patch • Each patch must be λ/2 in length Receiver • Receive a radar pulse with 2km pathlength • Isolator (Protection against transmitter feedback) • Magnitude and Phase Computer Interface and Control • FPGA Altera board NIOS II core – Monitor power – Control Radar pulse width and Range-gating of received signals • National Instruments Data Acquisition (DAQ) PCI board. – Desktop interface and file storage for post processing Software Post Process • Matlab image processing of CSV file. • SAR algorithm processing to reduces azimuthal ambiguity in radar Interface • Altera development software • NI board software • C based GUI Power • Bench-top devices • Regulated DC for FPGA • Power through the National Instruments card. Division of Labor • • • • Cameron-FPGA Programming Jon-Signal Processing Andrew-Antenna Design Nick-Hardware Integration and Testing Preliminary Schedule • Highly Modular • Plan on having hardware completed by Milestone 1 Risks and Contingency • Learning curve - Relatively inexperienced with antennas/radar • NTIA regulations - frequency control • Broadcast around 500MHz (Transparent frequency of Ice) • High Cost - Much covered by Stone Aerospace • Build vs. Buy • Time - Complex integration/ functional testing Budget Component Estimated Cost Receiver Unknown Transmitter Unknown FPGA $80 Antennae $100 NI interface card $500 PCB $100 Misc Parts $100 Power $50 Total $1000+ FIN • Questions?