From Minitrack to NAVSTAR: The early development of the global positioning system, 1955–1975
The paper outlines the early days of satellite navigation, focusing on the work of the Naval Research Laboratory (NRL) on systems that contributed to the later Global Positioning System (GPS). NRL's innovations included the Minitrack system for space surveillance, the development of high-precision timing systems for use in space, the Timation navigation satellite program, and the first two Navigation Technology Satellites (NTS-1 and NTS-2). NAVSTAR-GPS emerged as a joint Department of Defense (DoD) program in 1973, by which time much of the GPS concept had been developed and a number of GPS technologies had been tested.
NTS-1 (TIMATION-III) Quartz and Rubidium Oscillator Frequency Stability Results
Abstract : The report describes frequency stability results obtained from the NTS-1 satellite. NTS-1 has three on-board frequency sources: one quartz oscillator and two rubidium resonators. These are used to derive the precise time and frequency signals radiated by the spacecraft. The data taken from each of three 2.5-hr daily passes are time difference (range) or frequency difference (doppler). These data are incorporated into a single value for each pass which is subsequently used in computing long-time Allan-variance results. The results presented here employ single-frequency measurements at 335 MHz. Analysis of these results indicate an effect on measured frequency stability that correlates with a resonant term in the orbit. The results further indicate the rubidium frequency depends on the spacecraft temperature, which confirms previous NRL preflight analysis.
Proposed beam diagnostics instrumentation for the LANSCE refurbishment project
Presently, the Los Alamos National Laboratory is in the process of planning a refurbishment of various subsystems within its Los Alamos Neutron Science Center accelerator facility. A part of this LANSCE facility refurbishment will include some replacement of and improvement to existing older beam-diagnostics instrumentation. While plans are still being discussed, some instrumentation that is under improvement or replacement consideration are beam phase and position measurements within the 805-MHz side-coupled cavity linac, slow wire profile measurements, typically known as wire scanners, and possibly additional installation of fast ionization-chamber loss monitors. This paper will briefly describe the requirements for these beam measurements, what we have done thus far to answer these requirements, and some of the technical issues related to the implementation of the instrumentation.