ATS-5 trilateration support

The development of an L-band trilateration network capable of locating the ATS-5 satellite, determining the satellite's orbital elements, and predicting the satellite position was investigated. An automatic tone-code ranging transponder was used to compare ranging measurements and communications reliability for the VHF and L-band. The L-band transponder network, analytical techniques, and the determination of the Kepler orbit parameters are described along with the calibration procedures, operation procedures, and verification of trilateration position

Position surveillance using one active ranging satellite and time-of-arrival of a signal from an independent satellite

Position surveillance using one active ranging/communication satellite and the time-of-arrival of signals from an independent satellite was shown to be feasible and practical. A towboat on the Mississippi River was equipped with a tone-code ranging transponder and a receiver tuned to the timing signals of the GOES satellite. A similar transponder was located at the office of the towing company. Tone-code ranging interrogations were transmitted from the General Electric Earth Station Laboratory through ATS-6 to the towboat and to the ground truth transponder office. Their automatic responses included digital transmissions of time-of-arrival measurements derived from the GOES signals. The Earth Station Laboratory determined ranges from the satellites to the towboat and computed position fixes. The ATS-6 lines-of-position were more precise than 0.1 NMi, 1 sigma, and the GOES lines-of-position were more precise than 1.6 NMi, 1 sigma. High quality voice communications were accomplished with the transponders using a nondirectional antenna on the towboat. The simple and effective surveillance technique merits further evaluation using operational maritime satellites

Effect of Vertical Microphone Layer Spacing for a 3D Microphone Array

Subjective listening tests were conducted to investigate how the spacing between main (lower) and height (upper) microphone layers in a 3D main microphone array affects perceived spatial impression and overall preference. Four different layer spacings of 0m, 0.5m, 1m, and 1.5m were compared for the sound sources of trumpet, acoustic guitar, percussion quartet, and string quartet using a nine-channel loudspeaker setup. It was generally found that there was no significant difference between any of the spaced layer configurations, whereas the 0m layer had slightly higher ratings than the more spaced layers in both spatial impression and preference. Acoustical properties of the original microphone channel signals as well as those of the reproduced signals, which were binaurally recorded, were analyzed in order to find possible physical causes for the perceived results. It is suggested that the perceived results were mainly associated with vertical interchannel crosstalk in the signals of each height layer and the magnitude and pattern of spectral change at the listener’s ear caused by each layer

Feedback Control of Human Stress with Music Modulation

Mental stress has known detrimental effects on human health, however few algorithmic methods of reducing mental stress have been widely explored. While the act of listening to music has been shown to have beneficial effects for stress reduction, and furthermore, audio players have been designed to selectively choose music and other inputs with the intent of stress reduction, limited work has been conducted for real-time stress reduction with feedback control using physiological input signals such as heart rate or Heart Rate Variability (HRV). This thesis proposes a feedback controller that uses HRV signals from wearable sensors to perform real-time (< 1 second) modulations to music through tempo changes with the goal to regulate and reduce stress levels. A standardized, stress inducing test based on the popular Stroop test is also introduced, which has been shown to induce acute stress in subjects and can be used as a testing benchmark for controller design. Ultimately, a controller is presented that when used is not only able to maintain stress levels during stress-inducing inputs to a human but even provides de-stressing effects beyond baseline performance.No embargoAcademic Major: Electrical and Computer Engineerin