Implementing the NASA Deep Space LDPC Codes for Defense Applications

In this paper, a low-complexity LDPC decoder structure was proposed by optimizing the confidence propagation algorithm based on the deep space standard LDPC codes developed by the Consultative Committee for Space Data Systems (CCSDS). With the improved decoding algorithm, the structure made full use of the quasi-cyclic structure to reduce the variables in the decoder and the storage unit use for the index position of the check nodes, which saves the hardware resources greatly. Furthermore, the updating of the check nodes takes advantages of the information iterative structure of the JPL-LDPC decoder, which can reduce the computational complexity. By improving the searching methods, the computational complexity and the difficulty in FPGA implementation were reduced. The decoding performance of the decoder is close to that of the floating-point BP algorithm, which can be widely used in deep space communication with low signal-to-noise ratio.performance close to a floating-point the BP algorithm performance, can be widely used in deep space communications suitable for low signal-to-noise ratio transmission.

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A Modified Min-Sum Decoding Algorithm for LDPC Codes Based on Analysis of Overestimating Value

Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016) ◽

10.33012/2016.14808 ◽

2016 ◽

Author(s):

Xiaowen Chen ◽

Hongbo Zhao ◽

Zhijun He ◽

Wenquan Feng

Keyword(s):

Ldpc Codes ◽

Decoding Algorithm

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Performance Analysis of Multi-Constellation and Multi-Frequency GNSS Receivers in Deep Space

Proceedings of the 30th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2017) ◽

10.33012/2017.15138 ◽

2017 ◽

Author(s):

Yohan Park ◽

Jong-Hoon Won ◽

Ki-Ho Kwon

Keyword(s):

Performance Analysis ◽

Deep Space ◽

Gnss Receivers

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C. S. Lewis and the Truth about Angels

Journal of Inklings Studies ◽

10.3366/ink.2013.3.2.6 ◽

2013 ◽

Vol 3 (2) ◽

pp. 97-110

Author(s):

Janice Brown

Keyword(s):

Renaissance Literature ◽

Scholarly Work ◽

Deep Space ◽

The Subject

Lewis’s perspective on angels is apparent in The Discarded Image, his scholarly work on medieval and Renaissance literature. His preface to The Screwtape Letters reveals the seriousness with which he approaches the subject: it proposes that a mistaken view of angelic beings is more dangerous than ignorance of them. The space trilogy seeks to avert that danger. In it we are confronted by angelic eldila—inscrutable and holy beings inhabiting “deep space” who relentlessly accomplish the purposes of the Almighty. Characterized by absolute goodness and archetypal charity, they are serene yet they pulsate with energy. Lewis’s intense interest in angels is further apparent in a number of his poems. Throughout his work he depicts angels as real beings, inhabiting an actual universe, who actually participate our lives. They represent mysterious eternal realities, yet they are part of God’s daily providence.

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