Integer ambiguity resolution in GPS for spinning spacecrafts

A procedure to compute the integer ambiguity problem when a GPS receiver is used in a multiple antenna configuration attached to a rotating spacecraft is presented. The method is applied to a simulation of an experimental satellite which uses the GPS receiver for attitude determination     

Theory of LDV Tracking Systems

The application of frequency-tracking systems to the analysis of laser doppler velocimeter (LDV) signals degraded by background noise has been studied both theoretically and experimentally. Expressions are derived for both the correlation function and the expected value of the phase derivative in the general case of noise off center from the Doppler frequency, and these results are specialized to specific cases of practical interest. Laboratory measurements of output signal-to-noise ratio (SNR) and dc error, for varying input SNR and noise center frequency offset, show good agreement with the theoretical predictions.     

Independent Research Planning and Implementation

Spending company money wisely is a challenging job. The management approach used for selecting, executing, and applying company research projects is presented. Goals for research expenditures are discussed, together with methods of defining projects. The important interface between Government organization and company engineering and marketing is given. Optimum means of organizing and controlling selected research projects are covered, including management redirection when required. Approaches for maximizing creativity are also presented. All information presented is from actual experience and procedures now in use.     

Open systems architecture for integrated RF electronics

The Integrated Sensor System (ISS) program is defining an Open System Architecture (OSA) for Radio Frequency (RF) electronics, which represent the largest portion of an advanced aircraft's avionics flyaway cost. An integrated architecture is used to reduce costs in a number of ways, including time-sharing, centralization of resources, and reduction of the number of unique module types. The OSA approach extends these cost reductions by simplifying technology insertion, using well-understood standards, and increasing use of commercial hardware and software. This paper describes interim results. The work was funded by the Open Systems Joint Task Force (OS-JTF)     

The use of model-based test requirements throughout the productlife cycle

Test requirements, which are generally collected in multiple disparate formats throughout the life cycle of an electronic product, could be used in various applications that reduce test and development cycle times and increase the confidence in the final test program. Unfortunately, test requirements are seldom captured in a consistent format that may be processed by a computer, thus eliminating the possibility of using such requirements in an engineering application. Additionally, such an approach disallows test requirements captured in one segment of the product life cycle to be reused in subsequent life cycle stages. This paper describes a model-based methodology, specifically the Test Requirements Model (TeRM), which can be shown to facilitate the transfer of test-related product information between various stages of the life cycle. This transportability, in conjunction with an exchange format that can be processed by a computer, permits test requirement information to support value-added applications in the engineering process throughout the life cycle of a product     

Characteristics of a successful space system engineer

The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite was launched on June 24, 1999, on a three-year mission to explore the universe using the technique of high-resolution spectroscopy in the far-ultraviolet spectral region. The FUSE instrument comprises many subsystems, each of which contributes in an essential way to the success of the mission. The instrument system engineer oversees the engineering of all elements in such a complex technical project. In performing system engineering for the FUSE instrument's command, telemetry, data processing and data storage functions, and in leading the engineering efforts for the development of the FUSE instrument on-board computer, the author has learned valuable lessons about the characteristics that are prerequisite to success for a space system engineer. These characteristics fall under various categories of acquired, practical know-how. These categories are described with illustrations drawn from the development of the FUSE instrument. In addition to these practical skills and the concomitant knowledge, the system engineer needs personal integrity, which is the link that connects knowledge with know-how and makes them work together to motivate a team of subsystem engineers. This, too, will be discussed     

Methodology of construction and models of informative signals for a stationary miltichannel flow aerometric receiver of the helicopter air data system

Methodology of constructing a stationary multichannel flow aerometric receiver using the effects of deceleration and throttling of an incoming airflow and their circular transformation in the yaw plane is considered. The mathematical models and algorithms for processing primary informative signals entering along the channels of speed, altitude, angles of attack and slip of the helicopter air data system constructed on the basis of the aerometric receiver being proposed are obtained.