Planning assistance for the 30/20 GHz program, volume 1

Functional requirements for the 30/20 GHz communication system, planning assistance for the 30/20 GHz program, and a review of specified conceptual designs and recommendations are provided

Angular dispersion of radio waves in mobile channels

Multi-antenna techniques are an important solution for significantly increasing the bandwidth efficiency of mobile wireless data transmission systems. Effective and reliable design of these multi-antenna systems requires thorough knowledge of radiowave propagation in the urban environment. The aim of the work presented in this thesis is to obtain a better physical understanding of radiowave propagation in mobile radio channels in order to provide a basis for the improvement of radiowave propagation prediction techniques for urban environments using knowledge from 3-D propagation experiments and simulations combined with space-wave modelling. In particular, the work focusses on: the development of an advanced 3-D mobile channel sounding system, obtaining propagation measurement data from mobile radio propagation experiments, the analysis of measured data and the modelling of angular dispersive scattering effects for the improvement of deterministic propagation prediction models. The first part of the study presents the design, implementation and verification of a wideband high-resolution measurement system for the characterisation of angular dispersion in mobile channels. The system uses complex impulse response data obtained from a novel 3-D tilted-cross switched antenna array as input to an improved version of 3-D Unitary ESPRIT. It is capable of characterising the delay and angular properties of physically-nonstationary radio channels at moderate urban speeds with high resolution in both azimuth and elevation. For the first time, omnidirectional video data that were captured during the measurements are used in combination with the measurement results to accurately identify and relate the received radio waves directly to the actual environment while moving through it. The second part of the study presents the results of experiments in which the highresolution measurement system, described in the first part, is used in several mobile outdoor experiments in different scenarios. The objective of these measurements was to gain more knowledge in order to improve the understanding of radiowave propagation. From these results the dispersive effects in the angular domain, caused by rough building surfaces and other irregular structures was paid particular attention. These effects not only influence the total amount of received power in dense urban environments, but can also have a large impact on the performance and deployment of multi-antenna systems. To improve the data representation and support further data analysis a hierarchical clustering method is presented that can successfully identify clusters of multipath signal components in multidimensional data. By using the data obtained from an omnidirectional video camera the clusters can be related directly to the environment and the scattering effects of specific objects can be isolated. These results are important in order to improve and calibrate deterministic propagation models. In the third part of the study a new method is presented to account for the angular dispersion caused by irregular surfaces in ray-tracing based propagation prediction models. The method is based on assigning an effective roughness to specific surfaces. Unlike the conventional reflection reduction factor for Gaussian surfaces, that only reduces the ray power, the new method also distributes power in the angular domain. The results of clustered measurement data are used to calibrated the model and show that this leads to improved channel representations that are better matched to the real-world channel behavior

Engineering evaluations and studies. Volume 2: Exhibit B, part 1

Ku-band communication system analysis, S-band system investigations, payload communication investigations, shuttle/TDRSS and GSTDN compatibility analysis are discussed

Concepts for Short Range Millimeter-wave Miniaturized Radar Systems with Built-in Self-Test

This work explores short-range millimeter wave radar systems, with emphasis on miniaturization and overall system cost reduction. The designing and implementation processes, starting from the system level design considerations and characterization of the individual components to final implementation of the proposed architecture are described briefly. Several D-band radar systems are developed and their functionality and performances are demonstrated

Deep space communication and navigation study. Volume 2 - Communication technology Final report

Alternative types of communication systems for deep space probes and extent of aid spacecraft can provide for deep space navigatio

Development and Improvement of Airborne Remote Sensing Radar Platforms

With the recent record ice melt in the Arctic as well as the dramatic changes occurring in the Antarctic, the need and urgency to characterize ice sheets in these regions has become a research thrust of both the NSF and NASA. Airborne remote sensing is the most effective way to collect the necessary data on a large scale with fine resolution. Current models for determining the relationship between the world's great ice sheets and global sea-level are limited by the availability of data on bed topography, glacier volume, internal layers, and basal conditions. This need could be satisfied by equipping long range aircraft with an appropriately sensitive suite of sensors. The goal of this work is to enable two new airborne radar installations for use in cryospheric surveying, and improve these systems as well as future systems by addressing aircraft integration effects on antenna-array performance. An aerodynamic fairing is developed to enable a NASA DC-8 to support a 5-element array for CReSIS's MCoRDS radar, and several structures are also developed to enable a NASA P-3 to support a 15-element MCoRDS array, as well as three other radar antenna-arrays used for cryospheric surveying. Together, these aircraft have flown almost 200 missions and collected 550 TB of unique science data. In addition, a compensation method is developed to improve beamforming and clutter suppression on wing-mounted arrays by mitigating phase center errors due to wing-flexure. This compensation method is applied to the MVDR beamforming algorithm to improve clutter suppression by using element displacement information to apply appropriate phase shifts. The compensation demonstrated an average SINR increase of 5-10 dB. The hardware contributions of this work have substantially contributed to the state-of-the-art for polar remotes sensing, as evidenced by new data sets made available to the science community and widespread use and citation of the data. The investigations of aircraft integration effects on antenna-arrays will improve future data sets by characterizing the performance degradation. The wing-flexure compensation will greatly improve beam formation and clutter suppression. Increased clutter suppression in airborne radars is crucial to improving next generation ice sheet models and sea-level rise predictions

The 30/20 GHz communications system functional requirements

The characteristics of 30/20 GHz usage in satellite systems to be used in support of projected communication requirements of the 1990's are defined. A requirements analysis which develops projected market demand for satellite services by general and specialized carriers and an analysis of the impact of propagation and system constraints on 30/20 GHz operation are included. A set of technical performance characteristics for the 30/20 GHz systems which can serve the resulting market demand and the experimental program necessary to verify technical and operational aspects of the proposed systems is also discussed

High-Capacity Communications from Martian Distances

High capacity communications from Martian distances, required for the envisioned human exploration and desirable for data-intensive science missions, is challenging. NASA s Deep Space Network currently requires large antennas to close RF telemetry links operating at kilobit-per-second data rates. To accommodate higher rate communications, NASA is considering means to achieve greater effective aperture at its ground stations. This report, focusing on the return link from Mars to Earth, demonstrates that without excessive research and development expenditure, operational Mars-to-Earth RF communications systems can achieve data rates up to 1 Gbps by 2020 using technology that today is at technology readiness level (TRL) 4-5. Advanced technology to achieve the needed increase in spacecraft power and transmit aperture is feasible at an only moderate increase in spacecraft mass and technology risk. In addition, both power-efficient, near-capacity coding and modulation and greater aperture from the DSN array will be required. In accord with these results and conclusions, investment in the following technologies is recommended:(1) lightweight (1 kg/sq m density) spacecraft antenna systems; (2) a Ka-band receive ground array consisting of relatively small (10-15 m) antennas; (3) coding and modulation technology that reduces spacecraft power by at least 3 dB; and (4) efficient generation of kilowatt-level spacecraft RF power

Design of antenna array and data streaming platform for low-cost smart antenna systems

The wide range of wireless infrastructures such as cellular base stations, wireless hotspots, roadside infrastructures, and wireless mobile infrastructures have been increasing rapidly over the past decades. In the transportation sector, wireless technology refreshes require constantly introducing newer wireless standards into the existing wireless infrastructure. Different wireless standards are expected to co-exist, and the air space congestion worsens if the wireless devices are operating in different wireless standards, where collision avoidance and transmission time synchronisation become complex and almost impossible. Huge challenges are expected such as operation constraints, cross-system interference, and air space congestion. Future proof and scalable smart wireless infrastructures are crucial to harmonise the un-coordinated wireless infrastructures and improve the performance, reliability, and availably of the wireless networks. This thesis presents the detailed design of a novel pre-configurable smart antenna system and its sub-system including antenna element, antenna array, and radio frequency (RF) frontend. Three types of 90° beamforming antenna array (with low, middle and high gain) were designed, simulated, and experimentally evaluated. The RF frontend module or transmit and receive (T/R) module was designed and fabricated. The performance of the T/R module was characterised and calibrated using the recursive calibration method, and drastic sidelobe level (SLL) improvement was achieved using the amplitude distribution technique. Finally, the antenna arrays and T/R modules are integrated into the pre-configurable smart antenna system, the beam steering performance is experimentally evaluated and presented in this thesis. With the combination of practical know-how and theoretical estimation, the thesis highlights how the modern smart antenna techniques that support most cutting-edge wireless technology can be adopted into the existing infrastructure with minimum distraction to the existing systems. This is in line with the global Smart City initiative, where a huge number of Internet of Things (IoT) devices being wired, or wireless are expected to work harmoniously in the same premises. The concept of the pre-configurable smart antenna system presented in this thesis is set to deliver a future-proof and highly scalable and sustainable infrastructure in the transportation market

The Telecommunications and Data Acquisition Report

In space communications, radio navigation, radio science, and ground based radio and radar astronomy, activities of the Deep Space Network and its associated Ground Communications Facility in planning, in supporting research and technology, in implementation, and in operations are reported. Also included is TDA funded activity at JPL on data and information systems and reimbursable DSN work performed for other space agencies through NASA