FlexSARX Experimentation Description

0810-EX-PL-2014 Text Documents

USU Research Foundation

2014-11-10ELS_155509

FCC FORM 442: Exhibit A FlexSAR-X Experimentation Description Submitted To: Federal Communications Commission Office of Engineering and Technology Submitted By: Space Dynamics Laboratory Utah State University Research Foundation 1695 North Research Park Way North Logan, Utah 84341 DOCUMENT NUMBER: SDL/13-252 REVISION: B DATE: NOVEMBER 10, 2014

TABLE OF CONTENTS 1. INTRODUCTION................................................................................................................... 1 2. PROGRAM OF RESEARCH DESCRIPTION ................................................................... 1 2.1 Equipment Description ..................................................................................................1 2.2 Theory of Operation .......................................................................................................2 3. DESCRIPTION OF EXPERIMENT .................................................................................... 4 3.1 Experiment Objectives ...................................................................................................4 3.2 Proposed Locations ........................................................................................................4 3.3 Equipment Used .............................................................................................................5 4. PROGRAM CONTRIBUTION AND IMPACT .................................................................. 5 5. CONTACT INFORMATION ................................................................................................ 6 SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description i

1. INTRODUCTION The Space Dynamics Laboratory (SDL) submits this document as Exhibit A of FCC Form 442 and in accordance with Section 5.3(b), (d) and (h) of CFR Title 47 for the purpose of testing and further developing its Flexible Synthetic Aperture Radar (FlexSAR-X). This application is motivated by the desire to make a system change that increases the frequency bandwidth from a currently held license, call sign WG2XQF. SDL respectfully requests a 2-year license beginning Jan 1, 2015. This document provides supporting information and justification for the license application. 2. PROGRAM OF RESEARCH DESCRIPTION The FlexSAR-X program is a development effort funded internally at SDL. The objective is to build and test a SAR system that is capable of working in X-band as a research tool for airborne SAR applications. 2.1 EQUIPMENT DESCRIPTION The FlexSAR-X system consists of a Versa Module Eurocard (VME) chassis, solid state power amplifiers (SSPA) and an antenna. The VME chassis is 19”W x 15.75”H x 19.5”D, weighs 40 lbs and contains cards that provide a stable local oscillator, frequency conversion, pulse generation, analog to digital conversion, signal processing, and command and control. A chirp pulse is generated by direct digital synthesis (DDS) as it sweeps from low to high frequency, then up-converted to L-band and finally up-converted to X-band. The receiver reverses the process by down-converting from X-band to L-band and then from L-band to baseband. Bandpass and lowpass filters are incorporated on each stage of the transmitter and receiver to suppress unwanted out-of-band frequencies. The SSPA is only enabled during transmission of a pulse. Each antenna polarization, horizontal and vertical (H and V), has a dedicated channel. The transmitter and receiver share the same antenna polarizations and are isolated from each other by a circulator. Each channel is connected to an SSPA before being connected to the antenna through the circulator. The FRF-138, an X-band antenna built by First RF Corp, is used for transmit and receive. Figure 1. The FlexSAR-X VME chassis. SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description 1

The FlexSAR-X system specifications are detailed in Table 1. Table 1. FlexSAR-X Specifications RF Hardware Space Dynamics Laboratory Manufacture Frequency 9500 to 10,500 MHz Waveform Modulation Pulse Peak Transmitter Power 25 W (44 dBm) Avg Transmitter Power 2.4 W (3.8 dBm) (typ) Pulse Repetition 16,000 pps (typ), 20,000 pps (max) Frequency Transmitter Type Linear Frequency Modulated Pulse Transmitter Tuning Direct Digital Synthesizer Method Transmitter Frequency 0.0000001 ppm Stability Transmitter Power Amp Manufacture Aethercomm Model Number SSPA 9.5-10.5-25 Transmitter Harmonic Level 2nd (dBc) -60.4 (measured) Maximum Spurious -70.0 Emission Level Fundamental Curve (measured) -3.0 dBc (dBc) (measured) 9560.10, 10085.00 MHz -20 dBc 9543.00, 10130.68 MHz -40 dBc 9513.00, 10155.80 MHz -60 dBc 9459.00, 10185.95 MHz Transmitter Filter Bandpass, pre-power amplifier Employed Antenna Manufacture First RF Corp Antenna Model Number FRF-138 Antenna Gain 18.0 dBi Antenna Beamwidth Horizontal 40 degrees Vertical 10 degrees Antenna Mounting Antennas are aircraft-mounted, under aircraft wing, and facing downward 45 to 60 degrees away from nadir. Maximum operating altitude is 8500 AGL. 2.2 THEORY OF OPERATION The FlexSAR-X system collects data from an airborne platform while being controlled by an onboard operator. The RF card chassis is mounted inside the aircraft, and the antenna is mounted on the left side of the fuselage with a pointing vector perpendicular to the flight SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description 2

5000 ft 5000 to 8660 ft Figure 2. The antenna is mounted such that energy is directed to the left and angled downward towards the ground. direction and slanted downward 45 to 60 degrees, as shown in Figure 2. During the pre-flight planning process, areas of interest are identified that present scenes and objects to test the imaging fidelity of the SAR system. FlexSAR-X can operate in one of four modes: 1. Transmit on H polarization and receive on H polarization (HH) 2. Transmit on V polarization and receive on V polarization (VV) 3. Alternate between modes 1 and 2 above for every other pulse, which is called interleaved mode (HH/VV) 4. Alternate transmitting on H and V polarizations every other pulse but receive on both H and V polarization channels. This is called quadrature mode (HH HV/VH VV) The aircraft typically flies a race-track pattern around the area of interest, with FlexSAR-X actively transmitting and receiving energy during the straight portion of the track, as shown in Figure 3. Top-down view of a typical flight path used to collect data of an area of interest.The race-track pattern is pre-planned to present the scene at a nominal altitude and slant range. Typical operating altitude is 5000 ft AGL with slant ranges of 5000 to 8660 ft. The onboard operator monitors the aircraft position and heading to determine when the areas of interest enter the beam of the antenna. The operator turns on and off the transmitter when the area of interest enters and leaves the beam, respectively. The system operation modes and transmit on/off are controlled by the operator from a software application developed by SDL, but there are also panel switches that can disable the transmitter in the event the software is not functioning. The operator is an experienced member of SDL staff. SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description 3

Figure 3. Top-down view of a typical flight path used to collect data of an area of interest. 3. DESCRIPTION OF EXPERIMENT 3.1 EXPERIMENT OBJECTIVES The primary purpose for flight testing the FlexSAR-X system is to observe system performance in a real-world environment. This includes the characterization of key metrics, such as signal-to- noise ratio, and provides feedback for engineering further improvements. Also, it is desired to obtain a better understanding of how system parameters affect the sensor’s ability to resolve certain objects of interest in different clutter backgrounds. 3.2 PROPOSED LOCATIONS SDL seeks authority to carry out its test flights in one location as specified in the table and shown on the map in Figure 4. The area was chosen due to proximity to SDL facilities and the variety of natural and man-made scenes that will exercise the FlexSAR-X system’s capability. The area is defined by a center coordinate and radius as follows: Table 2. Location Specifications Center Latitude Center Longitude Radius (km) Altitude (ft) Logan 41°46’42” 111°51’12” 40 <8200 AGL A map of the proposed location and the surrounding area is shown in Figure 4. SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description 4

Figure 4. Map of the proposed locations and surrounding area. Map courtesy of Google Maps. Areas of interest within this circular area of operation will be chosen to meet test objectives and aircraft flight paths planned accordingly. These areas of interest are typically 1.5 miles in width and 3 miles in length. 3.3 EQUIPMENT USED The flight test will be carried out using a Cessna 337 aircraft. The FlexSAR-X system as described in Section 2.1 will be installed on the aircraft along with a Novatel CPT GPS/INS, and a Rockwell Collins IGS-200 GPS/INS. The First RF FRF-138 antenna will be mounted on the left side of the aircraft. 4. PROGRAM CONTRIBUTION AND IMPACT FlexSAR-X will be key to advancing the art of airborne SAR processing and image formation work at SDL and Utah State University (USU). It will enable SDL to work with other researchers, engineers and scientists across the country to expand SAR capability. Not only will SDL be able to use FlexSAR-X data for its own studies and advancement of SAR, but it will also be able to provide data to researchers at other institutions as well. FlexSAR-X can be easily configured for various airborne collection scenarios and studies, including concurrent collections with other sensors. The RF hardware will be studied and characterized in an effort to further refine and improve SAR measurements and images. SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description 5

5. CONTACT INFORMATION Questions regarding this application should be referred to the following individuals. Mark Jensen RF Engineer Space Dynamics Laboratory PH: (435) 713-3478 Scott A. Anderson Branch Head, Tactical Sensors Space Dynamics Laboratory PH: (435) 713-3444 SDL/13-252-B FCC Form 442: Exhibit A - FlexSAR-X Program Description 6


Document Created: 2014-11-10 09:46:06
Document Modified: 2014-11-10 09:46:06
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