Clear sky determination in uplink power control using dual time constants

An uplink power control system for use in a satellite terminal or a satellite gateway, the uplink power control system comprising:

• a receiving station operable to transmit uplink signals to and receive downlink signals from a satellite and comprising a programmable processing device or an application specific integrated circuit, the receiving station being either the satellite terminal or the satellite gateway;
• the programmable processing device or the application specific integrated circuit produces a value of a filtered short-term average downlink signal-to-noise-plus-interference ratio based on samples of a reference signal over a sampling time period, the processing device or the application specific integrated circuit updates a value of a filtered long-term average downlink signal-to-noise-plus-interference ratio based on the value of the filtered short-term average downlink signal-to-noise-plus-interference ratio;
• a power control module adjusts transmit power for the uplink signals based on the updated value of the filtered long-term average downlink signal-to-noise-plus-interference ratio and the filtered short-term average downlink signal-to-noise-plus-interference ratio received from the processing device or the application specific integrated circuit, wherein:
• when the value of the filtered long-term average downlink signal-to-noise-plus-interference ratio is greater than the value of the filtered short-term average downlink signal-to-noise-plus-interference ratio, the programmable processing device or the application specific integrated circuit adjusts the filtered long-term average downlink signal-to-noise-plus-interference ratio toward the filtered short-term average downlink signal-to-noise-plus-interference ratio at a first rate based on a first time constant, and
• when the value of the filtered long-term average downlink signal-to-noise-plus-interference ratio is not greater than or equal to the value of the filtered short-term average downlink signal-to-noise-plus-interference ratio, the programmable processing device or the application specific integrated circuit adjusts the filtered long-term average downlink signal-to-noise-plus-interference ratio toward the filtered short-term average downlink signal-to-noise-plus-interference ratio at a second rate based on a second time constant, a value of the second time constant being different from a value of the first time constant and the first rate being different from the second rate.