Internal and External Consistency of Doppler, Satellite-Triangulation, and Terrestrial Networks

1974 ◽  
Vol 28 (5) ◽  
pp. 474-479
Author(s):  
M. C. Pinch

The geodetic triangulation network in Canada was adjusted to compute results that can be used to relate the triangulation and Doppler satellite networks. The adjustment was run at reasonable cost, using program GALS and a technique for adjusting survey networks in sections.

1974 ◽  
Vol 28 (5) ◽  
pp. 467-473 ◽  
Author(s):  
D. E. Wells ◽  
E. J. Krakiwsky ◽  
D. B. Thomson

Three sample networks in Atlantic Canada are compared: one eight-station Doppler satellite network, one triangle of the North American densification of the USNGS world satellite triangulation network, and one terrestrial triangulation network. The method used to compute the Doppler network is described. The internal consistency of each network is assessed through analysis of covariance matrices. The externa! consistency between the Doppler and satellite triangulation, and between the Doppler and terrestrial networks is assessed by comparing the interstation distances in one network with the appropriate confidence regions in the other.


Author(s):  
Marlyn Kemper Littman

Satellite networks play a vital role in enabling essential critical infrastructure services that include public safety; environmental monitoring; maritime disaster recovery and reconnaissance; electronic surveillance; and intelligence operations for law enforcement, the military, and government agencies (Jamalipour & Tung, 2001). As demonstrated by the events following the terrorist attacks in the U.S. on the Pentagon in Washington, D.C. and the World Trade Center in New York City on September 11, 2001, satellite networks also provide redundant communications services when terrestrial networks are disrupted and/or unavailable. Despite their merits, satellite networks are nonetheless vulnerable to cyber attacks that pose threats to national security and the economy. Satellite networks transport voice, video, images, and data through the air as electromagnetic signals, thereby making these transmissions susceptible to interception. Technical advances enable the interconnectivity of satellite systems to public and private wireless and terrestrial networks including the Internet. These advances, however, amplify the risk of cyber attacks that can compromise critical infrastructure functions dependent on satellite networks in sectors that include information technology (IT) and telecommunications; defense; government; banking and finance; utilities; agriculture; emergency services; public health; and transportation (U.S. Department of Homeland Security (DHS), 2003; U.S. Government Accounting Office (GAO), 2004). As a consequence, satellite networks employ an array of security tools and mechanisms for countering costly and widespread cyber incursions and, thereby, ensuring the continuity of critical infrastructure operations. Those cyber attacks that are politically motivated and specifically designed to disrupt essential services are generally attributed to cyber terrorism. This chapter describes the technical fundamentals of satellite networks; examines security vulnerabilities; and explores initiatives for protecting the integrity of satellite network transmissions and operations from cyber incursions and physical attacks. Standards and protocols that safeguard satellite networks from unauthorized use and intentional disruptions and policies, and legislation that facilitate cyberspace asset protection are described. Capabilities of encryption in supporting secure satellite services and the distinctive attributes of the InterPlanetary Internet (IPN), also called the InterPlanetary Network, are explored.


1974 ◽  
Vol 28 (5) ◽  
pp. 606-615 ◽  
Author(s):  
Edward J. Krakiwsky ◽  
Donald B. Thomson

This paper reviews and analyzes some existing mathematical models used for the combination of terrestrial and satellite networks. They all contain three rotations, three translations and a scale factor, but differ in the choice of the point at which the rotations are made. Also, an alternative model is developed. It contains the above seven parameters and an additional set of rotations to account for systematic errors in the networks. An estimation technique is proposed for the separation of system and network rotations. Finally, an adjustment technique for the combination of pairs of satellite and terrestrial networks to yield a solution from all possible data is outlined.


2018 ◽  
Vol 25 (8) ◽  
pp. 1166-1170 ◽  
Author(s):  
Zhi Lin ◽  
Min Lin ◽  
Jian Ouyang ◽  
Wei-Ping Zhu ◽  
Symeon Chatzinotas

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6199
Author(s):  
Yanjun Yan ◽  
Huihui Xu ◽  
Ning Zhang ◽  
Guangjie Han ◽  
Mingliu Liu

Non-orthogonal multiple access (NOMA) has been extensively studied to improve the performance of the Terrestrial-Satellite Integrated Network (TSIN) on account of the shortage of frequency band resources. In this paper, the terrestrial network and satellite network synergistically provide complete coverage for ground users, and based on the architecture, we first formulate a constrained optimization problem to maximize the sum rate of the TSIN under the limited spectrum resources. As the terrestrial networks and the satellite network will cause interference to each other, we first investigate the capacity performance of the terrestrial networks and the satellite networks separately, in which the optimal power control factor expression is derived. Then, by constructing the relationship model between user elevation angle, beam angle and distance, we develop a dynamic group pairing schemes to ensure the effective pairing of NOMA users. Based on the user pairing, to obtain the optimal resource allocation, a joint optimization algorithm of power allocation, beam channel and base station channel resource is proposed. Finally, simulation results are provided to evaluate the user paring scheme as well as the total system performance, in comparison with the existing works.


2018 ◽  
Vol 1 (2) ◽  
pp. 1-10
Author(s):  
Nano Suyatna

In an effort to improve electricity services to customers, there needs to be a balance between the supply of electricity and revenue. Payment methods made by the Perusahaan Listrik Negara (PLN) use Postpaid and Prepaid methods. Because services with postpaid methods better meet customer satisfaction, this method is chosen. Sales Accounting Information System is an information technology-based accounting application to support financial transactions in a company to run faster, more precisely and accurately at a reasonable cost. In its operation, it takes competent human resources to not be a source of problems (human error) and adequate infrastructure. To overcome the obstacles that will arise, whether triggered by the application or by the human resources themselves, it is necessary to control both aspects. Based on this research it shows that the application  of  Sales Accounting Information Systems and existing human resources is sufficiently supportive  and  reliable  in  supporting the creation of good control as it is proven that the level of acceptance of sales targets is realized effectively and efficiently.    


2015 ◽  
Vol E98.B (8) ◽  
pp. 1715-1724 ◽  
Author(s):  
Zhu TANG ◽  
Chunqing WU ◽  
Zhenqian FENG ◽  
Wanrong YU ◽  
Baokang ZHAO ◽  
...  

Alloy Digest ◽  
1985 ◽  
Vol 34 (12) ◽  

Abstract ALCOA 6009 ALLOY offers the potential for lighter weight panels than steel or other aluminum alloy auto body sheet. It provides comparable performance, compatibility with existing production processes and a reasonable cost per unit of weight saved. It provides better dent resistance than most other aluminum body sheet alloys. Alloy 6009 has formability close to Aluminum 5182 with significantly higher weight savings. Scrap compatibility eliminates the segregation problems of mixed 2xxx and 5xxx scrap. Alloy 6009 scrap is readily recycled into itself or into casting alloys. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: Al-262. Producer or source: Aluminum Company of America.


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