PSEUDO INVARIANT AND COASTAL TARGET FEASIBILITY {DR.DAVID COTTENAND MEGAN AROGETI }UNIVERSITYOF SMALL SATELLITE RESEARCH LAB

OVERVIEW WHAT IS SPOC? PSEUDO INVARIANT TARGETS RESULTS Systems Tool Kit (STK), which is used for the sim- Spectral Ocean Color Satellite (SPOC) is an ad- All six sites had about 2000 access times over the ulation and analyses of our satellite in order to justable mulitspectral imager that will image the course of a year. Algeria 5 had the most (2244) and evaluate the performance of the satellite in sim- Earth from Low Earth Orbit (LEO). It will monitor Mauritania 1 had the least (1930).There was a total ulated time, will also provide a certain measure coastal wetlands status, estuarine water quality of 12,572 passes, and the average pass time across of feasibility for various targets. The desired tar- (wetland biophysical characteristics and phyto- all six sites was 862.6 seconds, or about 14 minutes gets include pseudo invariant targets, which are plankton dynamics), and near-coastal ocean pro- and 23 seconds. Solely based on pass times, each vital to the calibration of the satellite, and coastal ductivity. SPOC will quantify vegetation health, of these Radiometric Sites could feasibly used to targets such as , which are vital to primary and ocean productivity, suspended sedi- Figure 1: SPOC in orbit calibrate the satellite. completing the mission. ments, and organic matter in coastal regions. The simulation to test the feasibility ran for a sim- ulated time of a year. To ensure that the pass times PSEUDO INVARIANT TARGETS COASTAL TARGETS occurred in daylight, there was a Sun-Ground Ele- Pseudo Invariant Targets are required for the cali- The SPOC mission will return several multispec- vation Angle constraint put on SPOC from -60 de- bration of SPOC. They provide a means of verify- tral data products, using its SPOCEye payload grees to 60 Degrees. Using the Access tool, access ing sensor performance. All of the sites tested are system, related to oceanic productivity at various times, within the constraint, of the satellite to each Figure 2: Access times for the Pseudo Invariant Targets Radiometric Sites. A good site for calibration is target sites in order to study large-scale changes Radiometric Site were found. one with high spatial uniformity and high surface over time. Many of these targets will be on the reflectivity. The site should also be temporally in- East Coast of the . Below is a list of COASTAL TARGETS RESULTS variant The site should be arid, so that clouds and East Coast Targets* whose feasibility was studied. precipitation will not pose a problem. Six were In order to test the feasibility of ten tar- chosen to test. • Sapelo Island* gets on, or near, the East Coast of the • Skidaway Island* United States, a simulation was run over • NERR the course of one year. A Sun-Ground • Bayou Sauvage National Wildlife Reserve Elevation Angle constraint of -60 de- • Cumberland Island* grees to 60 degrees was put on SPOC to Figure 3: Sapelo Island Access times ensure that only pass times occurring in • * daylight would be considered. From the • St. Catharines Island Access Tool in STK, access times from SPOC to each of the Coastal Targets being studied were found. Figure 5: Libya 4 Radiometric Site • Ossabaw Island* On average, each site had about 2300 valid pass times. St. Catharines • Pseudo Invariant Targets in which the feasibility Wassaw Island* Island had the most with 3045 valid access opportunities and Bayou was tested: • St. Simons Island* Sauvage National Wildlife Reserve had the least with 2197 valid ac- cess opportunities. Sapelo Island, a key target for SPOC, had a total • Libya 1(24.42 N, 13.35 W) of 2243 access ties. Across all ten targets, there was a total of 23,156 • Libya 4 (28.55 N, 23.39 E) pass times. The average pass time for all 10 coastal targets in the • Mauritania 1 (19.40 N, 9.30 W) study lasted 855.9 seconds, or 14 minutes and 16 seconds. Just based • Mauritania 2 (20.85 N, 8.78 W) on this preliminary study, it is reasonable to say that each of these • Algeria 3 (30.32 N, 7.66 E) targets is feasible to image over the duration of the mission. • Algeria 5 (31.02 N, 2.23 W) Figure 4: SPOC passing targets Figure 6: East Coast Targets

REFERENCES FUTURE RESEARCH CONTACT INFORMATION [1]Adams, Arogeti, Ilango. (January 2018) SPOC • Refining current target lists; both Pseudo Invariant and Coastal targets. Web http://www.smallsat.uga.edu/ Experiment Plan, v1. UGA Small Satellite Re- • Creating an operation schedule. This schedule is dependent on knowing when SPOC will pass Email [email protected] search Laboratory over the intended targets and having the satellite take images. Phone 404 - 984 - 7627 [2] “Radiometric Sites.” Remote Sensing Tech- • Incorporate the fine sun sensor into the simulation. nologies , USGS, 8 Jan. 2013.