Spaceborne sensors (1983-2000 AD): A forecast of technology

A technical review and forecast of space technology as it applies to spaceborne sensors for future NASA missions is presented. A format for categorization of sensor systems covering the entire electromagnetic spectrum, including particles and fields is developed. Major generic sensor systems are related to their subsystems, components, and to basic research and development. General supporting technologies such as cryogenics, optical design, and data processing electronics are addressed where appropriate. The dependence of many classes of instruments on common components, basic R&D and support technologies is also illustrated. A forecast of important system designs and instrument and component performance parameters is provided for the 1983-2000 AD time frame. Some insight into the scientific and applications capabilities and goals of the sensor systems is also given

Technical approaches, chapter 3, part E

Radar altimeters, scatterometers, and imaging radar are described in terms of their functions, future developments, constraints, and applications

An analysis of a radio frequency sensor as a means to remotely sense selected surface topographies in an agriculture environment

Remote sensing is the science and art of obtaining information about an object, area or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area, or phenomenon under investigation. The remotely sensed data can be of many forms, including variations in force distribution, acoustic wave distribution, or electromagnetic energy distribution.Information thus acquired can be used for observing,monitoring, and studying planetary surfaces and environments. Because there are many ways to acquire data about targets of interest, there are many types of remote sensors that can be used, including visible, infrared, and active and passive microwave radio frequency (RF) sensors. This research specifically addresses active RF remote sensing. When one investigates RF sensors for agriculture (Ag) applications, the investigator finds very limited production use of RF technology. The limited use stems from the fact that RF applications for Ag equipment are usually driven by automotive desires and not by Ag needs. The hypotheses of this exploratory study was to determine the signal return profile (radiated return output power) or Radar Cross Section (RCS) are within the FCC Article 47 guidelines of three surface topographies. The three surfaces are tilled soil, grass, and concrete. Additionally, to a certain extent, this study tried to identify the capability of the radio frequency sensor as a means to measure ground speed of an Ag vehicle. The purpose of this exploratory study was to provide technical data (i.e., RCS) on the three surface topographies of tilled soil, grass, and concrete. Additionally, the purpose of the study was to investigate and provide information on four radio frequency radar principles that could be used in Ag applications, and to determine which of the four radar principles provide the optimum RCS over the selected surface topographies. Based upon the analyses of data, it was concluded that the correlation between multiple faceted surface topographies (e.g., tilled soil and grasses) was more statistically significant as to true ground speed than that of a smooth surface (i.e., concrete). Further, it was concluded that the correlation or feasibility of use between radio frequency technology and agriculture applications was again statistically significant. Given the outcomes of the study, recommendations for further study were warranted and may be utilized to further define the relationship between radio frequency sensor development and agricultural applications. It was recommended that this exploratory study be replicated. In addition, other recommendations for further study were also made

Millimetre-Resolution Photonics-Assisted Radar

Radar is essential in applications such as anti-collision systems for driving, airport security screening, and contactless vital sign detection. The demand for high-resolution and real-time recognition in radar applications is growing, driving the development of electronic radars with increased bandwidth, higher frequency, and improved reconfigurability. However, conventional electronic approaches are challenging due to limitations in synthesising radar signals, limiting performance. In contrast, microwave photonics-enabled radars have gained interest because they offer numerous benefits compared to traditional electronic methods. Photonics-assisted techniques provide a broad fractional bandwidth at the optical carrier frequency and enable spectrum manipulation, producing wideband and high-resolution radar signals in various formats. However, photonic-based methods face limitations like low time-frequency linearity due to the inherent nonlinearity of lasers, restricted RF bandwidth, limited stability of the photonic frequency multipliers, and difficulties in achieving extended sensing with dispersion-based techniques. In response to these challenges, this thesis presents approaches for generating broadband radar signals with high time-frequency linearity using recirculated unidirectional optical frequency-shifted modulation. The photonics-assisted system allows flexible bandwidth tuning from sub-GHz to over 30 GHz and requires only MHz-level electronics. Such a system offers millimetre-level range resolution and a high imaging refresh rate, detecting fast-moving objects using the ISAR technique. With millimetre-level resolution and micrometre accuracy, this system supports contactless vital sign detection, capturing precise respiratory patterns from simulators and a living body using a cane toad. In the end, we highlight the promise of merging radar and LiDAR, foreshadowing future advancements in sensor fusion for enhanced sensing performance and resilience

Earth resources: A continuing bibliography with indexes (issue 59)

This bibliography lists 518 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1 and September 30, 1988. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, oceanography and marine resources, hydrology and water management, data processing and distribution systems, and instrumentation and sensors

Earth resources: A continuing bibliography with indexes

This bibliography lists 579 reports, articles, and other documents introduced into the NASA scientific and technical information system. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economical analysis

Scientific opportunities using satellite surface wind stress measurements over the ocean

Scientific opportunities that would be possible with the ability to collect wind data from space are highlighted. Minimum requirements for the space platform and ground data reduction system are assessed. The operational uses that may develop in government and commercial applications of these data are reviewed. The opportunity to predict the large-scale ocean anomaly called El Nino is highlighted

Goddard Visiting Scientist Program for the Space and Earth Sciences Directorate

Progress reports of the Visiting Scientist Program covering the period from 1 Jul. - 30 Sep. 1992 are included. Topics covered include space science and earth science. Other topics covered include cosmic rays, magnetic clouds, solar wind, satellite data, high resolution radiometer, and microwave scattering

NASA Oceanic Processes Program

An overview of the recent accomplishments, present activities, and future plans is provided. Sections following the introduction provides summaries of current flight projects and definition studies, brief descriptions of individual research activities, and a bibliography of referred Journal Articles appearing within the last three years

Earth Resources: A continuing bibliography with indexes, issue 40

This bibliography lists 423 reports, articles, and other documents introduced into the NASA scientific and technical information system between October 1 and December 31, 1983. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economical analysis