H.F. ionospheric radar ground-scatter map showing land-sea boundaries by a spectral-separation technique

Blair, James C.; Melanson, L. L.; Tveten, L. H.

doi:10.1049/el:19690053

Cited by 9 publications

(2 citation statements)

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“…The oblique ionogram is characterized by a with a Hanning window [Harris, 1978] The spectral characteristics of the backscattered amination of the range-Doppler plots reveals weak energy depend upon whether the signal is being scat-but sharply defined Bragg lines over these frequencies tered from land or sea, and upon the propagation ahead of the much stronger F region returns. Typipath through the ionosphere [Blair et al, 1969]. In cally, F region returns are characterized by more the absence of any propagation effects, energy re-severe Doppler broadening than is the case for E turned from land would be characterised by a Dop-region returns, which is interpreted to be a consepier spectrum consisting of a delta function broad-quence of the more turbulent motion of electron denened by the response function of the system.…”

Section: Backscatter Soundermentioning

confidence: 99%

The frequency management system of the Jindalee over‐the‐horizon backscatter HF radar

Earl¹,

Ward²

1987

Radio Science

112

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Real-time frequency management is a vital element in the effective operation of an over-the-horizon backscatter (OTH-B) HF radar. In the case of the Australian project Jindalee OTH-B HF radar, a comprehensive frequency management system has been developed for this purpose. The frequency management system includes subsystems for ionospheric backscatter, vertical and oblique incidence sounding, HF spectral surveillance, and incorporates a low powered backscatter radar. The system is capable of providing real-time frequency management advice to the main radar, and of acquiring synoptic data for off-line analysis. In this paper we describe the hardware architecture and signal processing schemes, together with sample data, for each of the subsystems. We then describe the manipulation of the environmental data in order to provide frequency management advice to the main radar.behavior of the ionosphere can adequately be de-automation, in order that the advice did not require scribed in this manner, the ionosphere is specialist interpretation. The second requirement was characterized by large fluctuations about the for the system to gather data routinely (nominally 24 monthly median [Rush et al., 1974; Paul, 1983]. hours per day) with the objective of building up a Hence, as communicators have sought enhanced per-synoptic data base of the propagation environment, formance from HF circuits (e.g., the transmission of even when the main radar was not in use. In order digital data), it has been recognized that there is a that the data base could be used to provide quantitaneed for real-time frequency management of such cir-tire estimates of radar performance, all data had to cuits [CCIR, 1982]. be calibrated. The operation of an HF radar represents one ofThe purpose of this paper is to describe the design the most demanding applications of the ionosphere and capabilities of the system together with some as a transmission channel for radiowaves. Successful initial results. We also describe the manipulation of operation of such a radar necessitates careful selec-the environmental data to provide operational data tion of the operating frequency, based upon the cur-to the main radar. The statistical analysis of the derent state of the ionosphere, combined with the spe-tailed synoptic measurements will be reported in subsequent papers, while application of the system to the problem of providing frequency management support Copyright 1987 by the American Geophysical Union. to the main radar for the purpose of remote sea state Paper number 6S0553. sensing has already been reported [Earl and Ward, 0048.6604/87/006s-0553508.00 1986'].

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Section: Backscatter Soundermentioning

confidence: 99%

The frequency management system of the Jindalee over‐the‐horizon backscatter HF radar

Earl¹,

Ward²

1987

Radio Science

112

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“…Clearly, additional forms of ionospheric measurement or actual ground truth could help in correcting errors in the models and in refining the position estimates of specific targets. Such forms of truth are midpath vertical soundings, oblique soundings from points downrange in the radar coverage, HF beacon echoes, detections of identified targets with a priori known positions, detection of land-sea transitions by virtue of changes in ground echo Doppler shift between earth and ocean [Blair et al, 1969] with long integration times, and echoes from known terrain features. The latter approach is the subject of this paper.…”

Section: Introductionmentioning

confidence: 99%

Over‐the‐horizon radar target registration improvement by terrain feature localization

Barnum¹,

Simpson²

1998

Radio Science

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Abstract. This paper addresses the problem of over-the-horizon radar (OTHR) target position registration in the presence of ill-defined ionospheric structures. At present, OTHR is subject to frequent position uncertainties due to ionospheric abnormalities, such as tilts and ambiguous multipath propagation modes, that are difficult to model adequately during radar operation. The detection and registration of discrete terrain features in parallel with routine radar operations were studied with the goal of significantly reducing radar target position errors under most circumstances. The Wide Aperture Research Facility (WARF) experimental OTH radar testbed was modified to enable the automatic detection, processing, display, and registration of terrain features and HF repeater (beacon) echoes in parallel with aircraft detection and tracking operations. Many distinct terrain feature locations were studied in significant detail, including cities, mountain peaks, and an island, and the automatically determined position correction offsets were statistically compared with collocated beacons that served as ground truth. It was found that 100% of the offsets had expected errors of less than 5.7 nautical miles (1 nautical mile equals 1.852 km); and 93% of the offsets (with better ionospheric propagation) had expected errors of less than 3.2 nautical miles. We conclude from the research that terrain features can be used to provide coordinate registration benchmarks over an OTHR coverage area in the same way that beacons can be used.

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Ionospheric probing using pulsed radio waves at oblique incidence

Bradley

Eccles

King

1970

Journal of Atmospheric and Terrestrial Physics

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H.F. ionospheric radar ground-scatter map showing land-sea boundaries by a spectral-separation technique

Cited by 9 publications

References 0 publications

The frequency management system of the Jindalee over‐the‐horizon backscatter HF radar

The frequency management system of the Jindalee over‐the‐horizon backscatter HF radar

Over‐the‐horizon radar target registration improvement by terrain feature localization

Ionospheric probing using pulsed radio waves at oblique incidence

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