A compression system comprising: a compressor; at least one adjustable inlet guide vane (IGV); at least one variable stator vane (VSV) downstream from the at least one IGV, the at least one VSV being adjustable independently of the at least one IGV and the at least one IGV being adjustable independently of the at least one VSV; a compression control system including a controller, the controller including an IGV control unit and a VSV control unit; at least a first device configured to communicate with the compression control system and to provide at least a first compressor property value to the compression control system; at least a second device configured to communicate with the compression control system and to provide at least a second compressor property value to the compression control system; responsive to at least one of the first and second devices, an IGV position reference command produced by the IGV control unit; responsive to at least one of the first and second devices, a VSV position reference command produced by the VSV control unit; a guide vane positioning system configured to communicate with the controller to produce, responsive to at least the IGV position reference command, an IGV position command, and to produce, responsive to at least the VSV position reference command, a VSV position command; at least a first summing junction configured to communicate with the IGV control unit, the first summing junction also being configured to communicate with at least one of the first and second devices, and to send, responsive to the at least one of the first and second devices, a first output value to the IGV control unit; wherein: the first device is configured to measure a first compressor property and to provide to the first summing junction a measured first compressor property value, and the first compressor property is exhaust temperature. a compressor; at least one adjustable inlet guide vane (IGV); at least one variable stator vane (VSV) downstream from the at least one IGV, the at least one VSV being adjustable independently of the at least one IGV and the at least one IGV being adjustable independently of the at least one VSV; a compression control system including a controller, the controller including an IGV control unit and a VSV control unit; at least a first device configured to communicate with the compression control system and to provide at least a first compressor property value to the compression control system; at least a second device configured to communicate with the compression control system and to provide at least a second compressor property value to the compression control system; responsive to at least one of the first and second devices, an IGV position reference command produced by the IGV control unit; responsive to at least one of the first and second devices, a VSV position reference command produced by the VSV control unit; a guide vane positioning system configured to communicate with the controller to produce, responsive to at least the IGV position reference command, an IGV position command, and to produce, responsive to at least the VSV position reference command, a VSV position command; at least a first summing junction configured to communicate with the IGV control unit, the first summing junction also being configured to communicate with at least one of the first and second devices, and to send, responsive to the at least one of the first and second devices, a first output value to the IGV control unit; wherein: the first device is configured to measure a first compressor property and to provide to the first summing junction a measured first compressor property value, and the first compressor property is exhaust temperature. the first device is configured to measure a first compressor property and to provide to the first summing junction a measured first compressor property value, and the first compressor property is exhaust temperature.