A PHP Error was encountered
Severity: Warning
Message: fopen(/var/lib/php/sessions/ci_session5e0sh1445s9j76vure1bn1pa1dgpvhr6): Failed to open stream: No space left on device
Filename: drivers/Session_files_driver.php
Line Number: 177
Backtrace:
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)
Filename: Session/Session.php
Line Number: 137
Backtrace:
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Undefined array key "choices"
Filename: controllers/Detail.php
Line Number: 249
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 249
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 249
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 249
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: 8192
Message: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated
Filename: models/Detail_model.php
Line Number: 71
Backtrace:
File: /var/www/html/application/models/Detail_model.php
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: 8192
Message: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated
Filename: helpers/my_audit_helper.php
Line Number: 8919
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Undefined array key "choices"
Filename: controllers/Detail.php
Line Number: 256
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 256
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 256
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Undefined array key "usage"
Filename: controllers/Detail.php
Line Number: 257
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 257
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Undefined array key "usage"
Filename: controllers/Detail.php
Line Number: 258
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 258
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Undefined array key "usage"
Filename: controllers/Detail.php
Line Number: 259
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 259
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Undefined array key "usage"
Filename: controllers/Detail.php
Line Number: 260
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 260
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: controllers/Detail.php
Line Number: 260
Backtrace:
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
A PHP Error was encountered
Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 143
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
File: /var/www/html/application/helpers/my_audit_helper.php
File: /var/www/html/application/helpers/my_audit_helper.php
File: /var/www/html/application/helpers/my_audit_helper.php
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/application/controllers/Detail.php
File: /var/www/html/index.php
Real-time adaptive optics testbed to investigate point-ahead angle in pre-compensation of Earth-to-GEO optical communication. | LitMetric
We explore adaptive optics (AO) pre-compensation for optical communication between Earth and geostationary (GEO) satellites in a laboratory experiment. Thus, we built a rapid control prototyping breadboard with an adjustable point-ahead angle where downlink and uplink can operate both at 1064 nm and 1550 nm wavelength. With our real-time system, beam wander resulting from artificial turbulence was reduced such that the beam hits the satellite at least 66% of the time as compared to merely 3% without correction. A seven-fold increase of the average Strehl ratio to (28 ± 15)% at 18 μrad point-ahead angle leads to a considerable reduction of the calculated fading probability. These results make AO pre-compensation a viable technique to enhance Earth-to-GEO optical communication.
Publication Analysis
Top Keywords
investigate point-ahead
4
pre-compensation earth-to-geo
4
Similar Publications
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!
