Space debris is a growing environmental issue where both NASA and ESA predict at the current rate launching satellite and no debris removal program in place, Earth's orbital space may become inaccessible within the 50 years. One proposed method of reducing debris collisions in space is using a ground based continuous wave laser. This approach requires a precise measurement the space debris' range to determine the change of the orbit when attempting to maneuver the space debris and a ranging system compatible with a continuous wave laser.
The proposed method is modulating the continuous wave laser with pseudo random noise codes and measuring the time-varying delay using a matched filter. The matched filter uses parameter estimation to apply the time-varying delay onto a template code and correlated with the signal to measure the similarity. The correlation that produced the largest signal correlation provides an estimate of the different parameter used in the matched filter for the time-varying delay measurement. A second experiment was also carried out where the modulated signal is interfered with a local oscillator to improve the signal SNR and measure the time-varying delay. Both results are compared and presented for a space debris application.