Abstract:
The temporal kernel for the phase error variance due to atmospheric turbulence is calculated. This kernel, convolved with the servo transfer function, determines the temporal error of any turbulence compensation scheme.
Related Concept Videos
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
Compensation Mechanisms
The human body employs intricate mechanisms to counteract changes in blood pH, preventing conditions like acidosis (pH < 7.35) and alkalosis (pH > 7.45). These compensatory responses aim to restore normal arterial blood pH by engaging respiratory or renal systems, depending on the source of the imbalance.
Respiratory Compensation
This mechanism addresses metabolic-induced pH imbalances by adjusting breathing rates. Respiratory compensation begins within minutes of detecting a pH...
Respiratory Compensation
This mechanism addresses metabolic-induced pH imbalances by adjusting breathing rates. Respiratory compensation begins within minutes of detecting a pH...
Application of Linearization and Approximation
A drone flying through complex terrain often relies on more than one sensing method to estimate small changes in altitude. Along with direct measurements, air pressure provides a useful indirect indicator of vertical movement. Atmospheric pressure decreases as altitude increases, and this relationship is commonly described using an exponential model. Although accurate, converting pressure measurements into altitude values requires calculations that are too complex to perform repeatedly during...
Turbine-Governor Control
Turbine-governor control is crucial for maintaining power system stability by balancing turbine mechanical power output with electrical load demand. This mechanism ensures that generator frequency and rotor speed are within acceptable limits during load variations. Turbine-generator units store kinetic energy due to their rotating masses; this energy is released to meet the load requirement when the load increases. The electrical torque of turbines rises to meet the demand, whereas the...
Transient and Steady-state Response
In control systems, test signals are essential for evaluating performance under various conditions. The ramp function is effective for systems undergoing gradual changes, while the step function is suitable for assessing systems facing sudden disturbances. For systems subjected to shock inputs, the impulse function is the most appropriate test signal.
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state response.
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state response.
Doppler Effect - II
The Doppler effect has several practical, real-world applications. For instance, meteorologists use Doppler radars to interpret weather events based on the Doppler effect. Typically, a transmitter emits radio waves at a specific frequency toward the sky from a weather station. The radio waves bounce off the clouds and precipitation and travel back to the weather station. The radio frequency of the waves reflected back to the station appears to decrease if the clouds or precipitation are moving...
