Session
Weekend Session 8: Next on the Pad
Location
Utah State University, Logan, UT
Abstract
Launching October 2022, the SigNals Of Opportunity P-band Investigation (SNOOPI) is a 6U CubeSat dedicated to demonstrating spaceborne remote sensing of root zone soil moisture and snow water equivalent using signals of opportunity. P-band (240-500 MHz) frequencies are required to penetrate dense vegetation or snow and into the top 200 cm of soil, but this band is heavily subscribed. Rather than transmitting its own signal SNOOPI will observe reflected signals from the U.S. Navy’s Mobile User Objective System satellites. This makes planning observations challenging. The point of reflection is a function of both the transmitter and receiver satellite positions as well as terrain. The direct signal must be observed simultaneously on the same antenna pattern with sufficient gain. Ionospheric delay must also be accounted for. To satisfy these requirements and maintain a cadence of one observation per day, the SNOOPI science operations center at Purdue University has developed custom software for scheduling activities onboard the satellite. The software is highly automated, involving the user only in the definition of observation targets, priorities, and giving final approval to the proposed schedule. Orbit, attitude, power, communication, memory, and observation constraints are handled by a combination of linear programming and pattern search optimization methods. The purpose of this paper is to describe the challenges of scheduling observations for a signals of opportunity mission and illustrate how they were solved for SNOOPI.
Snooping Around: Observation Planning for the Signals of Opportunity P-Band Investigation (SNOOPI)
Utah State University, Logan, UT
Launching October 2022, the SigNals Of Opportunity P-band Investigation (SNOOPI) is a 6U CubeSat dedicated to demonstrating spaceborne remote sensing of root zone soil moisture and snow water equivalent using signals of opportunity. P-band (240-500 MHz) frequencies are required to penetrate dense vegetation or snow and into the top 200 cm of soil, but this band is heavily subscribed. Rather than transmitting its own signal SNOOPI will observe reflected signals from the U.S. Navy’s Mobile User Objective System satellites. This makes planning observations challenging. The point of reflection is a function of both the transmitter and receiver satellite positions as well as terrain. The direct signal must be observed simultaneously on the same antenna pattern with sufficient gain. Ionospheric delay must also be accounted for. To satisfy these requirements and maintain a cadence of one observation per day, the SNOOPI science operations center at Purdue University has developed custom software for scheduling activities onboard the satellite. The software is highly automated, involving the user only in the definition of observation targets, priorities, and giving final approval to the proposed schedule. Orbit, attitude, power, communication, memory, and observation constraints are handled by a combination of linear programming and pattern search optimization methods. The purpose of this paper is to describe the challenges of scheduling observations for a signals of opportunity mission and illustrate how they were solved for SNOOPI.
