Helicopter Ku-band SATCOM On-the-Move

Wilcoxson, Don; Sleight, Brian; O’Neill, J. J.; Chester, Dan

doi:10.1109/milcom.2006.302291

Cited by 12 publications

(7 citation statements)

References 8 publications

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“…from 20° to 90°) and azimuth (e.g. from 0° to 180°) relative to the helicopter heading reference [8] indicates that the link availability can vary between 93% to 75% of the area. A second antenna at the other side of the fuselage may eliminate this problem, especially when receive and transmit diversity technologies are included in the system [10].…”

Section: B Main Rotor Fuselage Blockagesmentioning

confidence: 99%

See 1 more Smart Citation

Helicopter propagation effects and countermeasures for reliable bandwidth efficient communications via satellite

Khan¹,

Febvre²,

Fines³

et al. 2013

31st AIAA International Communications Satellite Systems Conference

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Mobile communications via satellite require an unobstructed path between the user terminal and the satellite. Terminal installations on helicopters result in poor performance because their antennas are installed below the rotating blades and the link suffers from periodic blockages caused by the signal obstruction as well as significant ripples caused by multipath signal reflections. The helicopter propagation model as well as various countermeasures is presented. With the proposed techniques high bandwidth efficiency may be achievable to/from helicopters and at the same time the reliability of the link and service area increases.

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Section: B Main Rotor Fuselage Blockagesmentioning

confidence: 99%

“…After deinterleaving, the forward error correction (FEC) decoder shall be faced with an almost random channel state with sufficiently high average SNR so that data can be detected. This is a very effective technique used in almost all systems [7,8,9]. The FEC blocks must be sufficiently long (e.g.…”

Section: Effects On Link Performance and Countermeasuresmentioning

confidence: 99%

Helicopter propagation effects and countermeasures for reliable bandwidth efficient communications via satellite

Khan¹,

Febvre²,

Fines³

et al. 2013

31st AIAA International Communications Satellite Systems Conference

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“…To enable the use of the system with train or helicoptermounted terminals, an efficient means of dispersing energy to mitigate the effect of blockage/fading was devised [4]. In one of the example systems (see section IV.A), a rail channel application has periodic blockages due to electrical bridges (~5 ms every 636 ms) [5].…”

Section: S/2-bpskmentioning

confidence: 99%

“…This has been described for helicopter applications in [4]. In that application, the terminal's received forward link was used to track the blockage events and then predict when the next blockage event would occur.…”

Section: A Return Link Waveform Architecturementioning

confidence: 99%

Increased dynamic range multi-rate waveform for mobile satellite communications: Adaptive Coding Spreading and Modulation (ACSM)

O’Neill

Loh

Velayudhan

et al. 2010

2010 - Milcom 2010 Military Communications Conference

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For time-division multiplexed satellite communications links, a multi-rate waveform can enable substantial capacity gains over waveforms employing static coding and modulation. Using a multi-rate waveform such as DVB-S2 with adaptive coding and modulation (ACM), a user's data is transported with the most efficient modulation and forward error correction coding point that specific user can reliably receive.Many mobile satellite communication applications require a substantially smaller aperture or a lowerprofile antenna as compared to typical fixed-site very small aperture terminals (VSATs) for which DVB-S2 was designed. Over a wide area of operation, these smaller mobile terminals often cannot establish a link that observes regulatory powerspectral density limits using even the most robust modulation and code point that the DVB-S2 waveform offers.By adding the concept of adaptive direct sequence spreading to the adaptive coding and modulation, a more capable multi-rate waveform emerges that addresses a comprehensive set of mobile terminal platform types and scenarios. In this paper, the Adaptive Coding Spreading and Modulation (ACSM) concept is described and the capacity gains are quantified for several case studies. Also, a blockage mitigation technique employed within the ACSM concept that enables communications on train or helicopter mounted platforms is discussed.

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“…Communication of conventional systems becomes unstable because of the influence of mountains and tall buildings and even becomes impossible when roads are cut. Some earlier approaches have attempted to transmit burst signals during blockagefree periods based on synchronization with the blades [4] . However, pilot symbols and receiver synchronization make these approaches sensitive to the dynamics of platform movement.…”

Section: Introductionmentioning

confidence: 99%

Efficient helicopter−satellite communication scheme based on check-hybrid LDPC coding

Wang

Yin

2018

Tinshhua Sci. Technol.

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When implementing helicopter−satellite communications, periodical interruption of the received signal is a challenging problem because the communication antenna is intermittently blocked by the rotating blades of the helicopter. The helicopter−satellite channel model and the Forward Error Control (FEC) coding countermeasure are presented in this paper. On the basis of this model, Check-Hybrid (CH) Low-Density Parity-Check (LDPC)codes are designed to mitigate the periodical blockage over the helicopter−satellite channels. The CH-LDPC code is derived by replacing part of single parity-check code constraints in a Quasi-Cyclic LDPC (QC-LDPC) code by using more powerful linear block code constraints. In particular, a method of optimizing the CH-LDPC code ensemble by searching the best matching component code among a variety of linear block codes using extrinsic information transfer charts is proposed. Simulation results show that, the CH-LDPC coding scheme designed for the helicopter−satellite channels in this paper achieves more than 25% bandwidth efficiency improvement, compared with the FEC scheme that uses QC-LDPC codes.

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Helicopter Ku-band SATCOM On-the-Move

Cited by 12 publications

References 8 publications

Helicopter propagation effects and countermeasures for reliable bandwidth efficient communications via satellite

Helicopter propagation effects and countermeasures for reliable bandwidth efficient communications via satellite

Increased dynamic range multi-rate waveform for mobile satellite communications: Adaptive Coding Spreading and Modulation (ACSM)

Efficient helicopter−satellite communication scheme based on check-hybrid LDPC coding

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