2
$\begingroup$

Will launched time of a laser satellite teminal affect to transmission parameters, as data rate, power …?

As I know , the main limitation of lasercom is a direct line-of-sight path exists between a sender and a receiver and weather sensitive (e.g.heavy rain, fog, snow or strong wind, sun light).

$\endgroup$
2
$\begingroup$

Partial answer:

To some extent optical links can be almost completely immune to sunlight!

Temporal

The signals are modulated on a "carrier frequency" the baseline rate at which the laser is modulated. For TV and appliance remote controls using infrared LEDs the frequency is something like 38 kHz, but for a telemetry signal using a modulated communications laser it could be much, much higher, whereas sunlight will be almost DC or tens of Hz and light is modulated by clouds, plumes from cold gas thrusters, etc.

Spectral

Even a modulated laser will also be very narrow band, so a narrow-band optical filter on the receiver will further cut out sunlight. It might be 1 nm or even less and still have no problem passing almost all the laser light while cutting Sunlight down by a factor of order 1000; a 1 nm wide bandpass at say 850 nm will have roughly about 1/1000 of the Suns output in it.

Spatial

An optical receiving telescope will be centered on the position of the rocket and have perhaps a few degree field of view at most. A fast-acting, tiny electromechanical or MEMS mirror will keep the target centered on a small photodiode, and the amount of blue sky or background cloud coincident in this small area will be tiny.

enter image description here

Cubesat with active mirror pointing from this answer to Using what technology one can keep a spacecraft truly non rotating

See also the following, and links therein

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.