SNR, which increases as the square root of the number of dates, is comparable to the number of pixels that images can place on a target.
Click here for plots of predictions of single-date SNR as a function of asteroid size, distance, and declination, for Arecibo and Goldstone.
These calculations assume a radar cross section equal to 10% of the target cross section, a four-hour rotation period, a diffuse scattering law, and an equatorial view. SNR equals the received power of an optimally filtered echo in units of the r.m.s. receiver noise fluctuation.
Average Number of Objects per Year with Single-Date SNR Greater than | ||||
20 | 100 | 1000 | 5000 | |
---|---|---|---|---|
Main-Belt Asteroids | ||||
Before upgrade | 0.5 | 0.0 | 0.0 | 0.0 |
After upgrade | 35 | 5 | 0 | 0 |
Near-Earth Asteroids | ||||
Before upgrade, using actual statistics since 1980 | 3 | 0.9 | 0.3 | 0.1 |
After upgrade, with current NEA pool | 10 | 6 | 2 | 0.6 |
After Spaceguard Survey (lower bounds): | ||||
1 km or larger | 80 | 20 | 10 | 4 |
300 m or larger | 160 | 80 | 20 | 7 |
Science Expectation | ||||
disc-integrated properties: | |---> | |||
~30-parameter shape model: | |--> | |||
identify binary system: | |---> | |||
~100-parameter shape model: | |---> | |||
see craters clearly: | |---> | |||