Space Situational Awareness
Artist's impression of space debris around earth
(Credit: ESA)
Recent developments at Chilbolton Observatory are adding new capabilities to the 25 m dish and its 3 GHz radar (CAMRa).
With just some minor adjustments to the operation of the radar, it can be used to detect orbiting satellites and space debris. This is known as Space Situational Awareness (SSA). Some commonly-used earth orbits are becoming more crowded with debris, which poses a risk of damage to operational satellites and even manned orbiters.
Animation of increasing orbiting objects (link opens in a new window)
For objects in low earth orbit (LEO), radar is a more effective sensing method than optical telescopes. Recent ESA programmes have tested the ability of various radars worldwide to detect and characterise space debris. The CAMRa radar has taken part in these trials, including the CO-VI campaign.
Specifications of the upgraded (CAMRa radar)
| Parameter |
Value and comments |
|
Operating frequency
|
3076.5 MHz |
| Antenna gain |
53.5 dBi |
| Beamwidth |
0.28 deg. (FWHM; -3dB, 1-way) |
| Polarisation |
Transmit: H Receive: H and V |
| Transmitter type |
Cavity magnetron |
| Peak power |
700 kW |
| Average power |
25 W |
| Pulse repetition frequency |
71.428 Hz |
| Pulse width and coding |
0.5 µs uncoded rectangular |
| Receiver type |
Superhet, log and I/Q channel |
| Noise figure |
3.5 dB, plus duplexing losses (~2 dB) |
| IF centre frequency, bandwidth |
30 MHz centre, 4 MHz bandwidth |
| Data acquisition system |
7 channels, 12-bit/channel |
In addition, the radar can detect changes in the signal from a target. This can be used to determine more detailed information, such as whether the target is tumbling or whether a larger satellite has moving parts which scan in a regular pattern.
