Showing papers on "L band published in 2002"
TL;DR: The new Pleiades concept proposed by CNES is based on a detailed mission analysis taking into account the evolution of the user needs and technical capabilities (smaller satellites), showing the request for 10 space components.
19 citations
TL;DR: To accommodate low-bit correlators in remote sensing STAR, a novel band division correlation (BDC) processor is proposed, which improves the time-coherence of each correlated brightness signal while it also maintains the system bandwidth and noise-equivalent sensitivity of a conventional STAR radiometer.
Abstract: The phase coherence limitations of L-band digital correlation radiometry are investigated for receiver architectures that use low A/D converter resolution (1-3 bits). Statistical models and measurements of a 1.4 GHz digital radiometer system show that coarse quantization can cause excess fringe washing losses which degrade the spatial resolution capabilities in synthetic thinned array radiometry (STAR) implementations. For single-bit STAR, excess fringe washing is discernible immediately away from the boresight direction and, further from the center of the image, can result in as much as 2 dB loss in visibility information. To accommodate low-bit correlators in remote sensing STAR, a novel band division correlation (BDC) processor is proposed. BDC improves the time-coherence of each correlated brightness signal while it also maintains the system bandwidth and noise-equivalent sensitivity of a conventional STAR radiometer. Analytical and numerical solutions are presented for the point spread function of a 27 m L-band STAR sensor to evaluate the band-slicing technique. The results show that with 4 subband channels, BDC improves swath edge resolution from 17.0 to 10.2 km and reduces correlation loss from 2.5 to 0.2 dB.
17 citations
24 Jun 2002
TL;DR: This work explores the use of products from climate model reanalysis projects as ancillary data to exploit the S-194 data for a broad range of soil moisture conditions by employing a radiative transfer approach.
Abstract: In preparing for future L band soil moisture satellite missions, investigators have employed ground, aircraft and satellite sensors. Of the satellite sensors, there has been only one instrument that provides any heritage at L band, the Skylab S-194 instrument that operated in the 1970s. Data from theses missions have been analyzed and reported in a few applications, however, these studies utilized either the linear regression approach or the Antecedent Precipitation Index (API). We explore the use of products from climate model reanalysis projects as ancillary data to exploit the S-194 data for a broad range of soil moisture conditions by employing a radiative transfer approach. The spatial resolution and the accuracy of reanalysis outputs are major limitations to this approach.
16 citations
09 Mar 2002
TL;DR: Satellite broadcasting of radio programs is an effective means of serving large and distributed markets as discussed by the authors, which can provide about 100 high quality music, voice, and data channels to users spread over a vast geographic area.
Abstract: Satellite broadcasting of radio programs is an effective means of serving large and distributed markets. A space-based radio system can provide about 100 high quality music, voice, and data channels to users spread over a vast geographic area. Employing digital technology and an elaborate system design, this approach significantly outperforms traditional AM and FM radio broadcasting in signal quality, program quantity, and service availability. Motorists can enjoy their program of choice uninterrupted driving coast to coast. There are two providers of satellite radio in the USA: Sirius Satellite Radio and XM Satellite Radio. Both systems are expected to be fully operational in 2002. This paper will offer an overview of satellite radio and will introduce the Sirius Satellite Radio network. Field trial results including performance data and propagation characteristics will be discussed. It will be shown that satellite radio seamlessly serves both urban and rural areas.
12 citations
20 May 2002
TL;DR: In this article, an interesting structure of the microwave phase discriminator MPD was described, which has been built in microstrip technique onto a single substrate, and the power splitting network was equipped with additional wideband phase shifter.
Abstract: This article refers to high resolution digital frequency discriminators DFDs. An interesting structure of the microwave phase discriminator MPD was described. It has been built in microstrip technique onto single substrate. The power splitting network was equipped with additional wideband phase shifter. It was done in order to shape DFD characteristics. Thanks to design of each of the discriminator's microwave components and carefully worked out evaluation algorithm, an 11-bit frequency resolution was achieved. The accuracy of the manufactured discriminator is better than /spl plusmn/0.6 MHz over the frequency range of 0.76-1.27 GHz.
6 citations
01 Dec 2002
3 citations
Journal Article•
TL;DR: In this study, the N-modulation waves model and the 3rd order intercept point input level method (IIP3) in [RC Sagers (1983)] was applied by using parameters of direct spread code division multiple access system as WBMR and personal handyphone system (PHS) as a typical NBMR.
Abstract: At starting of the service operation of 2 GHz band IMT-2000 system in Japan, it is important to make clear the mutual interference problem which may occur between IMT-2000 mobile radio systems and existing mobile radio systems, etc. Concerning about this study, Japanese Association of Radio Industries and Businesses established an investigation and examination meeting from fiscal year 1998 to 2001. After this meeting, especially about nonlinear interference that will occur when interfering wave is very high and nonlinearity of interfered receiver amplifier becomes important, specialist team of nonlinear interference is continuing to study this problem. This paper describes the theoretical study result on intermodulation (IM) spectrum generated by a wideband continuous modulation wave and generation of interfering wave caused by IM, on the nonlinear interference by which a narrowband mobile radio system (NBMR) is disturbed by a wideband mobile radio system (WBMR). In this study, the N-modulation waves model and the 3rd order intercept point input level method (IIP3) in [RC Sagers (1983)] was applied by using parameters of direct spread code division multiple access (DS-CDMA) system as WBMR and personal handyphone system (PHS) as a typical NBMR. The bit error rate characteristics (BER) of PHS receiver were estimated through comparison of measured data and theoretical analysis result of the desired signal and undesired signal ratio (D/U) to BER. The comparison result of estimated and measured BER of a NBWR receiver was reported by using a guard band between WBMR and NBWR system receiver as a parameter.
2 citations
Patent•
15 Oct 2002
TL;DR: An integral antenna that receives television and FM radio signals and satellite radio signals includes a multi-element antenna portion having a boom (12), supported by a mast (22) and a plurality of parallel, spaced apart dipole elements (2) supported by the boom and extending perpendicularly to the longitudinal axis of the boom as mentioned in this paper.
Abstract: An integral antenna that receives television and FM radio signals and satellite radio signals includes a multi-element antenna portion having a boom (12) supported by a mast (22) and a plurality of parallel, spaced apart dipole elements (2) supported by the boom (12) and extending perpendicularly to the longitudinal axis of the boom (12), and a helical antenna portion (20) having an element helically wound about a supporting core. The helically wound antenna portion (20) receives satellite radio signals, and the multi-element antenna portion (2) receives television and/or FM radio signals. The satellite radio antenna portion (20) is mounted at one of various 'null-points' (4) situated on the multi-element antenna portion (2) where current flow in the multi-element antenna portion is minimal.
1 citations
24 Jun 2002
TL;DR: Results imposes certain sampling constraints on validation activities planned for 2002-2004 in conjunction with the Advanced Microwave Scanning Radiometer to be deployed from Aqua by mid 2002.
Abstract: In a recent experiment in Huntsville, Alabama in, 1998 involving ground-based L (1.4 GHz), S (2.6 GHz), and C (6.34 GHz) band passive microwave sensors, special attention was given to near surface sampling in an attempt to shed additional light on characterizing emitting depth. Using a forward radiative transfer model with detailed near surface gravimetric observations, 50% of the total energy observed at L band emitting depth was found to be emitted from a depth of 3.5-5.0 cm. Likewise, 50% of the total energy observed at C band was emitted from a depth of 0.8-1.4 cm, depending on moisture and temperature conditions. As such, these results imposes certain sampling constraints on validation activities planned for 2002-2004 in conjunction with the Advanced Microwave Scanning Radiometer to be deployed from Aqua by mid 2002.
Patent•
19 Jun 2002
TL;DR: In this paper, an advanced color filter of a video color camera sensor is provided to fabricate a band filter for transmitting light as dividing an S band and an L band of the first array.
Abstract: PURPOSE: An advanced color filter of a video color camera sensor is provided to fabricate a band filter for transmitting light as dividing an S band and an L band of the first array, and to generate a color signal with 1 set for 2 pixels of an original color composed of a 2-band filter only, thereby reducing a defective proportion and improving resolution CONSTITUTION: A prism(10) receives an incident light to separate the light into a light toward a straight drive and a light toward 90 degrees, and supplies the light of the straight drive to an S filter(20), then supplies the light of 90 degrees to an L filter(30) The S filter transmits the received light through an S band to supply the light to an optical sensor(40) The L filter transmits the received light through an L band to supply the light to an optical sensor(50) The optical sensor(40) supplies an S signal divided as a short wave band to a matrix(60) The optical sensor(50) supplies an L signal divided as a long wave band to the matrix The matrix reproduces R, G, B colors by a variable value combination of a resistor and a transistor by receiving the S and the L signals, and outputs the R, G, B signals through signal output terminals(c, d, e)