A model of the vertical distribution of the electron concentration in the ionosphere and its application to oblique propagation studies

Dyson, P. L.; Bennett, J. A.

doi:10.1016/0021-9169(88)90074-8

Cited by 130 publications

(79 citation statements)

References 12 publications

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“…A current model for electron density, called multiquasi-parabolic (MQP) profile, considers its variations as a succession of parabolic portions [7]. Despite possible continuity defaults when deriving the corresponding refractive index, this representation is known as effective.…”

Section: Ionospheric Channel Simulationmentioning

confidence: 99%

Development and test of a trans-horizon communication system based on a MIMO architecture

Ndao

Erhel

Lemur

et al. 2013

J Wireless Com Network

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A multiple-input multiple-output (MIMO) system for trans-horizon radio communications within the high-frequency (HF) band (3 to 30 MHz) is presented. The diversity of transmitted polarizations is proposed as an alternative to spatial diversity in order to limit the aperture of antenna arrays at both ends of the radio link. In a theoretical step providing the estimation of capacity gain for different MIMO architectures, a 2 × 2 MIMO solution transmitting two complementary circular polarizations is identified as a balanced trade-off between performance increase and complexity. The design of the corresponding system is described with a focus on antenna arrays and the kind of signal processing that should be implemented. This novel communication system has been tested on a 280-km-long radio link. The first results underline a data transfer rate reaching a value of 24.09 kbps (in a 4.2-kHz bandwidth) that significantly exceeds the current standards for HF modems.

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Section: Ionospheric Channel Simulationmentioning

confidence: 99%

Development and test of a trans-horizon communication system based on a MIMO architecture

Ndao

Erhel

Lemur

et al. 2013

J Wireless Com Network

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“…Assume the signal bounces off from the target and arrives at the nth receiver along L mn backward propagation paths, where the reflection height of the lth (l = 1, · · · , L mn ) backward propagation path is h mnl . Note that the number of forward and backward paths as well as the reflection heights can be computed based on the MQP model [3] based on the known antenna position, signal frequency, and given cell-under-test. The received signal at receiver n due to the transmission of transmitter m is a superposition of the signals from all K m L mn paths, which is…”

Section: Assumptions and Received Signal Modelmentioning

confidence: 99%

“…τ Fmk (x Tm , y Tm , γ, β), the time delay of the signal propagating from the mth transmitter to the scatter located at (γ, β) via the kth forward path, and τ Bmnl (x Rn , y Rn , γ, β), the time delay of the mth transmitted signal propagating from the scatter at (γ, β) to the nth receiver via the lth backward path, can be computed via the MQP model [3]. This interesting but complicated computation is documented in [21] but omitted here for brevity.…”

Section: Assumptions and Received Signal Modelmentioning

confidence: 99%

“…The commonly used models for describing the ionospheric state usually divide the ionosphere into several layers. These models include the international reference ionosphere (IRI) model [1], the Chapman ionosphere model [2], and the multi-quasi-parabolic (MQP) ionospheric model [3], etc. In OTH radar, transmit signals can travel through different ionospheric layers to reach the target depending on their frequencies, and the signal which bounces off the target can also travel through different ionospheric layers before reaching the receivers, leading to multiple propagation paths, a phenomenon called multipath ionospheric propagation (MIP).…”

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confidence: 99%

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Signal model and detection performance for MIMO-OTH radar with multipath ionospheric propagation and non-point targets

et al. 2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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Taking into account the existence of multipath ionospheric propagation (MIP), this paper develops the received signal model for a non-point target for multiple-input multipleoutput skywave over-the-horizon (MIMO-OTH) radar for the first time. The model describes the ionospheric state, the number of propagation paths between a radar antenna and the target center, as well as the statistics of the reflection coefficients. It is shown that varying system parameters, such as antenna positions and signal frequencies, can result in causing the model to change from a case with highly correlated reflection coefficients to a case with virtually uncorrelated reflection coefficients. The proposed model is used to solve a target detection problem. It is shown that it is possible to exploit the MIP to improve the detection performance of the MIMO-OTH radar.Index Terms-Detection, multipath, non-point target.1. INTRODUCTION Skywave over-the-horizon (OTH) radar employs ionospheric reflection of signals to detect targets beyond visual range. The performance of the OTH radar system relies heavily on the state of the ionosphere. The commonly used models for describing the ionospheric state usually divide the ionosphere into several layers. These models include the international reference ionosphere (IRI) model [1], the Chapman ionosphere model [2], and the multi-quasi-parabolic (MQP) ionospheric model [3], etc. In OTH radar, transmit signals can travel through different ionospheric layers to reach the target depending on their frequencies, and the signal which bounces off the target can also travel through different ionospheric layers before reaching the receivers, leading to multiple propagation paths, a phenomenon called multipath ionospheric propagation (MIP). In traditional OTH radar systems, approaches have been proposed to attempt to eliminate MIP, for example, by selectively choosing the operational frequency, employing a transmit/receive array with higher angular reso-

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“…Bertel et al (1987) found that this method with three data points appeared to be unstable in the iterative calculation, and consequently increased the number of data points to 15 or more to improve the stability. Norman (2003) further improved this method by using the quasi-parabolic segment (QPS) model derived by Dyson and Bennett (1988). The QPS model uses five QPSs to represent the E, F1, and F2 ionospheric layers.…”

Section: Introductionmentioning

confidence: 99%

A new inversion algorithm for backscatter ionogram and its experimental validation

et al. 2014

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Abstract.Oblique backscatter sounding is a powerful tool for detecting and monitoring the ionosphere continuously at a remote distance. High-frequency (HF) backscatter ionograms provide the amplitudes of backscatter signals with respect to group path or time delay against operating frequency. Application of inversion algorithm to a backscatter ionogram can extract useful information regarding the ionospheric electron density along the propagation paths. The present study proposes a new inversion algorithm on basis of simulated annealing method to acquire the leading edge of sweep-frequency ionogram, which is subsequently validated by ionospheric vertical sounding data. Quantitative comparisons between the vertical sounding measurements and the inversion results obtained from oblique backscatter sounding indicate that the new algorithm enables us to overcome the instability issue that traditional inversion algorithm faces and output reliable information of ionospheric inversion with satisfactory efficiency, thus providing a robust alternative for ionospheric detection based on oblique backscatter ionograms especially when the ionosphere is calm with slow changes.

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A model of the vertical distribution of the electron concentration in the ionosphere and its application to oblique propagation studies

Cited by 130 publications

References 12 publications

Development and test of a trans-horizon communication system based on a MIMO architecture

Development and test of a trans-horizon communication system based on a MIMO architecture

Signal model and detection performance for MIMO-OTH radar with multipath ionospheric propagation and non-point targets

A new inversion algorithm for backscatter ionogram and its experimental validation

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