Heterodyne telemetry and data transmission at 10.6 microns
Abstract
Analytical models and block diagrams are presented for transmitters and receivers employing heterodyned 10.6 micron CO2 laser impulses for ranging and data transmission. CO2 wavelengths have a low atmospheric attenuation coefficient, accommodate broad spectral tuning which can be exploited to offset ECM interferences and are safe to use due to the opacity of the human eye to CO2 wavelengths. The basic principles of radio signal heterodyne detection through interference effects are reviewed. Techniques are explored for improving the angular directivity and SNR of the detectors, compensating for atmospheric turbulence and statistically eliminating speckle effects which appear as false targets. The responses of HgCdTe photocell detectors are examined, along with the usage of pulse modulation and ground-ground monomode laser telemetry. Experimental results are reported regarding the performance of devices for target detection with 5 m and 0.2 m/sec accuracy at several kilometers distance and for high rate data transmission.
- Publication:
-
Revue Technique Thomson CSF
- Pub Date:
- June 1985
- Bibcode:
- 1985RvT....17..227D
- Keywords:
-
- Data Transmission;
- Optical Communication;
- Optical Heterodyning;
- Telemetry;
- Atmospheric Turbulence;
- Carbon Dioxide Lasers;
- Directivity;
- Light Modulation;
- Signal To Noise Ratios;
- Speckle Patterns;
- Superheterodyne Receivers;
- Communications and Radar