VARIATION OF METEOR ECHO RATES WITH RADAR SYSTEM PARAMETERS

Observations made with crossed-polarization radar system systems do not support the suggestion that the ionized meteor trail may act as a strong filter–polarizer of the incident radio wave. Experiments have been carried out to determine the variation of normal meteor echo rates with transmitter power, antenna gain, and radio wave length, and all confirm Lovell's scattering formula, provided that account is taken of the effective broadening of the scattering pattern of the meteor trail with increasing wave length. The limiting sensitivity of the 9.22 m. 200 kw. radar is determined to be about 9th magnitude. During a strong visual shower the observed increase in visual rates and low-power radar rates, compared to high-power radar rates, is explained by assuming that the magnitude distribution of the shower meteors differs from the normal nonshower distribution.

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Probabilistic analysis of ambiguities in radar echo direction of arrival from meteors

10.5194/amt-2020-157 ◽

2020 ◽

Author(s):

Daniel Kastinen ◽

Johan Kero

Keyword(s):

Bayesian Method ◽

Direction Of Arrival ◽

Radar System ◽

Stable Region ◽

Radar Signal ◽

Ambient Atmosphere ◽

Radar Systems ◽

Mu Radar ◽

Meteor Trail ◽

The Antarctic

Abstract. Meteors and hard targets produce coherent radar echoes. If measured with an interferometric radar system, these echoes can be used to determine the position of the target through finding the Direction Of Arrival (DOA) of the incoming echo onto the radar. If the DOA of meteor trail plasma drifting with the ambient atmosphere is determined, the neutral wind at the observation altitude can be calculated. Specular meteor trail radars have become widespread scientific instruments to study atmospheric dynamics. Meteor head echo measurements also contribute to studies of the atmosphere as the meteoroid input of extraterrestrial material is relevant for a plethora of atmospheric phenomena. Depending on the spatial configuration of radar receiving antennas and their individual gain patterns, there may be an ambiguity problem when determining the DOA of an echo. Radars that are theoretically ambiguity free are known to still have ambiguities that depend on the total radar Signal to Noise Ratio (SNR). In this study we investigate robust methods which are easy to implement to determine the effect of ambiguities on any hard target DOA determination by interferometric radar systems. We apply these methods specifically to simulate four different radar systems measuring meteor head and trail echoes using the multiple signal classification (MUSIC) DOA determination algorithm. The four radar systems are the middle and upper atmosphere (MU) radar in Japan, a generic Jones 2.5λ specular meteor trail radar configuration, the Middle Atmosphere Alomar Radar System (MAARSY) radar in Norway and the The Program of the Antarctic Syowa Mesosphere Stratosphere Troposphere Incoherent Scatter (PANSY) radar in the Antarctic. We also examined a slightly perturbed Jones 2.5λ configuration used as a meteor trail echo receiver for the PANSY radar. All the results are derived from simulations and their purpose is to grant understanding of the behaviour of DOA determination. General results are: there may be a region of SNRs where ambiguities are relevant; Monte Carlo simulation determines this region and if it exists; the MUSIC function peak value is directly correlated with the ambiguous region; a Bayesian method is presented that may be able to analyse echoes from this region; the DOA of echoes with SNRs larger then this region are perfectly determined; the DOA of echoes with SNRs smaller then this region completely fail to be determined; the location of this region is shifted based on the total SNR versus the channel SNR in the direction of the target; asymmetric subgroups can cause ambiguities even for ambiguity free radars. For a DOA located at the zenith, the end of the ambiguous region is located at 17 dB SNR for the MU radar and 3 dB SNR for the PANSY radar. The Jones radars are usually used to measure specular trail echoes far from zenith. The ambiguous region for a DOA at 75.5° elevation and 0° azimuth ends at 12 dB SNR. Using the Bayesian method it may be possible to analyse echoes down to 4 dB SNR for the Jones configuration, given enough data points from the same target. The PANSY meteor trail echo receiver did not deviate significantly from the generic Jones configuration. The MAARSY radar could not resolve arbitrary DOAs sufficiently well to determine a stable region. However, if the DOA search is restricted to 70° elevation or above by assumption, stable DOA determination occurs above 15 dB SNR.

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Solar Radiations in the 4–6 Metre Radio Wave-Length Band

Classics in Radio Astronomy ◽

10.1007/978-94-009-7752-5_16 ◽

1946 ◽

pp. 166-167

Author(s):

J. S. Hey

Keyword(s):

Radio Wave ◽

Wave Length

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METEOR ECHO DURATION AND RADIO WAVE LENGTH

Canadian Journal of Physics ◽

10.1139/p53-097 ◽

1953 ◽

Vol 31 (7) ◽

pp. 1121-1135 ◽

Cited By ~ 5

Author(s):

D. W. R. McKinley

Keyword(s):

Radio Wave ◽

Short Duration ◽

Wave Length ◽

The Other ◽

Radar Echoes ◽

Radio Equipment ◽

Straight Lines

The durations of radar echoes from meteors have been observed simultaneously on 9.22 m. and 5.35 m., and also on 9.22 m. and 2.83 m. The ratio of durations on two wave lengths decreases with increasing duration by a factor of two over the observed range, deviating significantly from the accepted square law of wave length. Plotting the log of the ratio against the log of the duration yields two straight lines of different slopes, one in the short-duration range and the other applying to the longer echoes. General empirical formulae are developed to predict the echo duration on one radio equipment in terms of the duration of the same echo recorded by another apparatus of different sensitivity and wave length.

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Adaptive Management of System Parameters of Maintenance, As Well As Repair and Optimization of Spare Parts, Tools and Accessories of the Integrated Radar System on the Basis of Reliability Model and Control Data

Proceedings of the International Scientific Conference "Far East Con" (ISCFEC 2018) ◽

10.2991/iscfec-18.2019.145 ◽

2019 ◽

Cited By ~ 2

Author(s):

S. Boev ◽

D. Kiryanov ◽

S. Matveeva

Keyword(s):

Adaptive Management ◽

Spare Parts ◽

Radar System ◽

Reliability Model ◽

Control Data ◽

System Parameters ◽

And Control

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Design and Comparative Study Among Antennas of GCS for Telemetry Communication System of UAV

IJITEE (International Journal of Information Technology and Electrical Engineering) ◽

10.22146/ijitee.50866 ◽

2020 ◽

Vol 3 (4) ◽

pp. 99

Author(s):

Iswandi Iswandi ◽

Aria Rangga Suryamanggala ◽

Dewanto Wicaksono ◽

Eny Sukani Rahayu

Keyword(s):

Communication System ◽

Antenna Gain ◽

Power Budget ◽

Transmitter Power ◽

Communication Links ◽

Aerial Vehicle ◽

Basic Parameters ◽

Link Budget ◽

Parameters Measurement ◽

Transmission Test

Recently, Unmanned Aerial Vehicle (UAV) becomes a popular and interesting technology for researchers and academics because it has high potential to be implemented in various fields. The UAV operation is managed by a Ground Control Station (GCS) on which requires a communication system to send control signals and acquire data collected by sensors on UAV. The longer the UAV's flying distance needs a higher transmission power budget that can be achieved by increasing transmitter power, increasing receiver sensitivity, or increasing antenna gain. However, the design of communications systems on a flying platform is limited by the following constraints. The transmitter, receiver, and antenna must be compact, lightweight, and energy-efficient to save battery on the vehicle. Although the antenna does not directly influence the energy consumption from the battery, an increase in antenna gain usually requires an increase of the antenna dimension that causes higher weight and or reduces the aerodynamics. Therefore, the most efficient way to increase the link budget is by modifying the antenna on the GCS. This paper describes the analysis of antennas commonly used in GCSs for UAV communication links, namely the Yagi-Uda, bi-quad, and double bi-quad antennas. The antenna is designed to work at a frequency of 433.5 MHz following the transceiver device used. The antenna designs are numerically simulated then fabricated for evaluating their performance. The testing is done on the following issues, i.e. the antenna's basic parameters measurement, the ground-to-ground transmission test, and the ground to air transmission test. The test results show that the double bi-quad gives better performance than the other two other testing antennas.

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