Satellite Broadcasting Research Articles

Simulation Platform for SINS/GPS Integrated Navigation System of Hypersonic Vehicles Based on Flight Mechanics.

In this study, a simulation platform for an integrated navigation algorithm for hypersonic vehicles based on flight mechanics is designed. In addition, the generation method of inertial measurement unit data and satellite receiver data is introduced. First, the interface relationship between a high-precision six-degree-of-freedom (6DoF) model and the simulation platform in the launch-centered Earth-fixed frame is introduced. Three-axis theoretical specific force and angular velocity are output by the 6DoF model. Accelerometer and gyroscope error models are added, and integral processing of the specific force and angular velocity is performed to obtain velocity increment of the accelerometer and the angular increment of the gyroscope. These data are quantified to obtain the accelerometer and gyroscope pulses. The satellite’s pseudo-range and pseudo-range rate as well as its position and velocity are obtained from the theoretical position, velocity, the attitude of the hypersonic vehicle’s 6DoF model output, and the global positioning system (GPS) satellite broadcast ephemeris. The simulation data can be used for the verification of the loose and tight coupling integrated navigation algorithms. The simulation test verifies the accuracy of the designed method.

Quantum secrecy in thermal states II

In this paper we consider a scheme for cryptographic key distribution based on a variation of continuous variable quantum key distribution called central broadcast. In the continuous variable central broadcast scheme, security arises from discord present in the Hanbury Brown and Twiss effect from a thermal source. The benefit of this scheme is that it expands the range of frequencies into the microwave regime. Longer wavelengths—where the thermal photon number is higher and correlations remain robust over long distances—may even be preferable to optical wavelengths. Assuming that Alice controls the source but not the distribution of the light (e.g. satellite broadcasts), then we demonstrate that the central broadcast scheme is robust to an entangling cloner attack. We establish the security of the protocol both experimentally and theoretically.

A Bandwidth Statistical Multiplexing and Control Method for Satellite Broadcasting

In the field of satellite data broadcasting, the management quality of data broadcasting bandwidth is directly related to the throughput of the broadcasting system and plays an important role in the performance of satellites. In this paper, for the sun-synchronous orbit meteorological satellite broadcasting which has the conventional product files and emergency information, a broadcast bandwidth statistical multiplexing and control method is designed for bandwidth management. It can be used for the management of broadcasting between regular products and emergency information, as well as internal broadcasting among regular products. This paper is the first to apply common multiplexing of PID and channel mode (CMPCM) to satellite broadcasting. The test verified that the broadcast channel of the parameters and the broadcast schedule management channel resources achieved statistical multiplexing of bandwidth, ratio of channel management functions, and data broadcast control. Broadcasting occupation ratio (BOR) and broadcasting file error ratio (BER) improved significantly. This is significant for improving the efficiency of satellite uplink broadcasting.

Hierarchical Classification Method for Radio Frequency Interference Recognition and Characterization in Satcom

The Quality of Service (QoS) and security of Satellite Communication (Satcom) are crucial as Satcom plays a significant role in a wide range of applications, such as direct broadcast satellite, earth observation, navigation, and government/military systems. Therefore, it is necessary to ensure that transmissions are incorruptible, particularly in the presence of challenges such as Radio Frequency Interference (RFI), which is of primary concern for the efficiency of communications. The security of a wireless communication system can be improved using a robust RFI detection method, which could, in turn, lead to an effective mitigation process. This paper presents a new method to recognize received signal characteristics using a hierarchical classification in a multi-layer perceptron (MLP) neural network. The considered characteristics are signal modulation and the type of RFI. In the experiments, a real-time video stream transmitted in the direct broadcast satellite is utilized with four modulation types, namely, QPSK, 8APSK, 16APSK, and 32APSK. Moreover, it is assumed that the communication signal can be combined with one of the three significant types of interference, namely, Continuous Wave Interference (CWI), Multiple CWI (MCWI), and Chirp Interference (CI). In addition, two robust feature selection techniques have been developed to select more informative features, which leads to improving the classification precision. Furthermore, the robustness of the trained techniques is assessed to predict unknown signals at different Signal to Noise Ratios (SNRs).

Development of New UHD-1 (4K)/UHD-2 (8K) UHDTV Satellite Broadcasting System in Japan

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">UHD-1/4K and UHD-2/8K satellite broadcasts were launched on 1 December 2018 in Japan. One of these services, the broadcast of UHD-2/8K was the first of its kind in the world. This broadcasting system adopts high-efficiency video coding (HEVC) with highly efficient compression performance, a newly developed (Integrated Services Digital Broadcasting) ISDB-S3 transmission system, which uses the 16APSK modulation scheme and other new technologies. In this paper, we provide details of the new UHD-1/4K and UHD-2/8K services, focusing on standardizing technical specifications and practical ways to introduce new reception systems into households</i> .

Intelligent Optimization of Availability and Communication Cost in Satellite-UAV Mobile Edge Caching System With Fault-Tolerant Codes

Mobile computing provides storage and computation resources of proximal devices to satisfy the real-time and low-energy communication demands of the Internet of Things (IoT). However, in the areas without terrestrial base station infrastructures, the IoT sensors have trouble implementing reliable and stable connections, which results in the difficulties of data gathering and data caching. In this paper, we consider a space-air-ground integrated mobile edge caching IoT system composed of satellite and unmanned aerial vehicles (UAVs), where LEO satellite broadcasts data, and UAVs collect the data from decentralized ground sensors. Since the sensors’ low-power property leads data loss, fault-tolerant codes are employed for availability protection. We first derive the exact expressions of system availability and communication cost for data repair and collection. Then, to address the problems of the lower availability, we exploit an intelligent optimization to determine the erasure coding parameters. Lastly, we further optimize the system parameters, i.e., communication ranges and unit power costs of UAV and decentralized sensors, to minimize the total communication cost. Simulation results show that, compared to MDS codes and regenerating codes, adaptive minimum storage regenerating (AMSR) codes with optimized parameters can significantly reduce total communication cost and maintain availability of the system.

Analysis and Assessment of BDS-2 and BDS-3 Broadcast Ephemeris: Accuracy, the Datum of Broadcast Clocks and Its Impact on Single Point Positioning

For the global ordinary users, the broadcast ephemeris plays important roles in positioning, navigation and timing (PNT) services. With the construction of a new generation of the BeiDou navigation satellite system (BDS), the development of BDS has entered the era of globalization. It is meaningful for global users to analyze and assess the BDS-2 and BDS-3 broadcast ephemeris. Therefore, the satellite orbits and clock offsets calculated by broadcast ephemeris are compared with the precise orbit and clock offset products provided by three analysis centers (i.e., Helmholtz Centre Potsdam German Research Center for Geosciences (GFZ), Wuhan University (WHU) and Shanghai Astronomical Observatory (SHA)), and the corresponding signal-in-space range error (SISRE) and the orbit-only SISRE are analyzed to assess the accuracy of BDS broadcast ephemeris. Due to the upgrade of BDS-3 satellite hardware technology and inter-satellite links payload and the development of satellite orbit determination algorithm, the accuracy of broadcast orbit and clock offsets has been greatly improved. The root mean square (RMS) of BDS-3 broadcast orbit errors is improved by 86.30%, 89.47% and 76.86%, and the standard deviation (STD) is improved by 79.41%, 77.00% and 76.78% compared with BDS-2 in the radial, along-track and cross-track directions. The corresponding RMS and STD of all BDS-3 satellite clock offsets are improved by 40.34% and 52.49% than that of BDS-2, respectively. Meanwhile, the mean RMS and STD are 1.78 m and 0.40 m for BDS-2 SISRE, 1.72 m and 0.34 m for BDS-2 orbit-only SISRE, 0.50 m and 0.14 m for BDS-3 SISRE, and 0.17 m and 0.04 m for BDS-3 orbit-only SISRE. It is noteworthy that the average broadcast-minus-precise (BMP) clock values of BDS-2 and BDS-3 are inconsistent, which can indirectly prove that the datum of broadcast clock offsets for BDS-2 and BDS-3 are inconsistent. The inconsistency of the datum of satellite clock offsets and receiver hardware delay bias between BDS-2 and BDS-3 will result in the inter-system bias (ISB) on the receiver segment. For JAVAD TRE_3 receivers, the ISB is relatively small and thus can be ignored. However, for the TRIMBLE ALLOY, SEPT POLARX5, CETC-54-GMR-4016, CETC-54-GMR-4011, GNSS-GGR and UB4B0-13478 receivers, estimating ISB can improve the positioning accuracy of single point positioning (SPP) by 20.15%, 19.81% and 12.76% in north, east and up directions, respectively.

Assessment of BDS-3 global positioning service: ephemeris, SPP, PPP, RTK, and new signal

The BDS-3 preliminary system was declared functional on December 27, 2018. It enables positioning service on a global scale. This study conducts a comprehensive investigation of the BDS-3 global service from the perspective of positioning, including satellite ephemeris, benefits of the new BDS-3 satellites, and the new signal effect on three positioning modes: single-point positioning (SPP), precise-point positioning (PPP) and real-time kinematic (RTK). First, the broadcast and precise ephemeris availabilities of 18 BDS-3 Medium Earth orbit (MEO) satellites from January to June 2019 are investigated. Due to the shorter operational timespans of BDS-3 satellites, their broadcast and precise ephemeris files retrieved from Multi-GNSS Experiment (MGEX) have 1.2–19.4% and 10.9–13.77% discontinuities, respectively, while the discontinuities of BDS-2 satellite broadcast and precise ephemeris are only 0.1 and 2.1%. Second, the BDS-3 satellite orbit accuracies and clock precisions are significantly improved, i.e., below 0.5 m and 1.82 ns compared to 2 m and 2.91 ns for BDS-2 because of the inter-satellite links of BDS-3 satellites. Third, an average of 4.4–5.7 BDS satellites can be observed at stations located in North/South America, and 8.9 for the European station FFMJ located in Germany after the BDS-3 global system announcement. As a result, continuous positioning is feasible in these regions. As to four Asia–Pacific stations, their SPP accuracies are improved by 12.1–60.2% compared to those of the BDS-2-only solution. Meanwhile, the PPP and RTK convergence times of Asia–Pacific stations are also shortened. Last but not least, the new B1C signal does not bring convincing improvement to PPP and RTK positioning accuracies in this study, due to the limited number of available B1C new signals at this time.

Design of a wideband right‐handed circularly polarized array of miniaturized mushroom‐shaped antennas for direct broadcast satellite application

AbstractIn this study, a wideband right‐handed circularly polarized (RHCP) array of microstrip patch antennas, for direct broadcast satellite (DBS, 12.2‐12.7 GHz) services have been presented. The single element of the array is a two‐dimensional mushroom‐shaped fractal antenna of resonating frequency 12.49 GHz and an impedance bandwidth of 1.12 GHz. The proposed single element is designed by etching a pair of Minkowski square boxes in one of the two opposite sides of a regular octagon. Furthermore, a thin slot of length equal to one side of the regular octagon is placed in‐between the two Minkowski boxes, which results in the proposed mushroom‐shaped radiating element. The proposed four‐element linear array resonates at 12.47 GHz and gives an impedance bandwidth of 1.04 GHz. The feed network of the array is designed in such a manner to make the array structure very compact. The fabricated single element gives an RHCP gain of 5.25 dBic and its corresponding circular Polarization (CP) bandwidth of 200 MHz. The array gives an RHCP gain of 11.59 dBic and a CP bandwidth of 460 MHz. The measured CP bandwidth of the fabricated array prototype ensures 92% coverage of the entire DBS band with circularly polarized wave, and hence can be used for its related applications.

Estimation of the DCB for the BDS-3 new signals based on BDGIM constraints

The hardware delay difference for different navigation signals in satellite or receiver channels is called Differential Code Bias (DCB). DCB is a major error of global navigation satellite system (GNSS), which may lead to tens of Total Electron Content unit (TECu) ionospheric delay errors or several-meter ranging errors. The basic system of BeiDou Navigation Satellite System has opened services and three new navigation signals, namely B1C, B2a at the end of 2018, and B2b at the end of 2019. As the BeiDou satellite broadcast clock difference is based on the phase center of the B3I signal antenna, it is necessary to estimated the DCB values of the new navigation signals relative to B3I. Considering that BDS broadcasts the BeiDou global ionospheric delay correction model (BDGIM) parameters with the highest precision, the method of solving satellite or receiver DCB based on the BDS-3 BDGIM parameter constraint is proposed and verified. Theoretical analysis shows that the mean square error of daily solution is about 0.63–1.96 ns. The measured data of 25 iGMAS stations from January 1 to 30, 2019, are used for verification. The results show that the solution precision of satellite DCB is better than 1.0 ns and that of receiver DCB is slightly worse. This method does not need the support of external ionospheric products and provides a possibility for online real-time estimating of the satellite and receiver DCB.

An off‐center‐fed compact wideband antenna with truncated corners and parasitic patches for circular polarization

A novel single-fed circularly polarized wideband, compact and lightweight microstrip patch antenna (MPA) is proposed. The antenna is designed in a simple two-phase procedure to achieve wideband and circular polarization. In the first phase, an off-centered L-shaped feeding arrangement is employed to obtain wideband (|S11| < −10 dB) over 10.6 GHz to 14.7 GHz with an improved peak gain of 5.25 dBi. In the second phase, the radiating patch is symmetrically truncated and two modified-parasitic patches are added to ensure <3 dB axial ratio over 11.4 GHz to 12.8 GHz. A prototype has been fabricated and the measured results show close agreement with the simulation. The proposed antenna is suitable for fixed satellite and broadcast satellite communication in Ku-band range.

Generation of DFMC SBAS corrections for BDS-3 satellites and improved positioning performances

The next-generation satellite-based augmentation system (SBAS) will follow the dual-frequency multi-constellation (DFMC) protocol and broadcast satellite clock-ephemeris corrections and integrity information via GPS L5-like signals to improve the accuracy and integrity for GNSS dual-frequency users. BeiDou Navigation Satellite System (BDS)-3 B1C/B2a dual-frequency users will obtain a higher positioning accuracy using DFMC clock-ephemeris corrections. This paper focuses on an approach for the generation of DFMC SBAS corrections and its preliminary results. Analyzing the signal-in-space ranging error characteristics of BDS-3 satellites reveals that it is impossible to obtain orbits that are more accurate than the broadcast orbits using regionally distributed SBAS monitoring stations. Therefore, a novel DFMC SBAS correction generation approach for BDS-3 satellites is proposed in which only clock offset corrections are calculated. The effectiveness of the proposed approach is validated using measurements from mainland China. By using clock corrections only, B1C/B2a dual-frequency users can obtain the best accuracy. The results of the BDS-3 B1C/B2a dual-frequency positioning experiment show that the user equivalent ranging error is reduced from 0.59 m to 0.37 m with clock corrections but is reduced to only 0.43 m with the addition of clock-ephemeris corrections. With clock corrections only, the 95% positioning errors are reduced from 3.57 m to 1.53 m and from 3.79 m to 2.24 m in the horizontal and vertical directions, respectively, indicating a 48% reduction in positioning errors compared to users without SBAS corrections; however, the error reduction is only 40% with clock-ephemeris corrections.

Transmission System of 4K/8K UHDTV Satellite Broadcasting

Transmission System of 4K/8K UHDTV Satellite Broadcasting

A tie-point zone group compaction schema for the geolocation data of S-NPP and NOAA-20 VIIRS SDRs to reduce file sizes in memory-sensitive environments

The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) disseminates weather and climate-related satellite data to its users via satellite broadcast. As part of this, the EUMETSAT Advanced Retransmission Service (EARS) provides Sensor Data Records (SDR) from the United States satellites Suomi National Polar-orbiting Partnership (S-NPP) and NOAA-20. Due to bandwidth constraints and for cost-reduction reasons for the upload to the disseminating satellite, a near-lossless compaction method has been developed for the geolocation data of the data capturing satellites’ Visible Infrared Imager Radiometer Suite (VIIRS) instrument. The geolocation data are compacted by storing only the data representation for so called tie-points which form tie-point zones and are grouped in tie-point zone groups. Compression factors of 120 for M-Band, 479 for I-Band, and 154 for Day/Night Band, not using HDF5 internal compression on neither the input nor the output, and 56 for M-Band, 210 for I-Band, and 89 for Day/Night Band, using HDF5 internal compression on both the input and output, respectively, are reached. The compaction process introduces an error of about 1 ​m RMSE for the position in latitude/longitude and of about 0.001° RMSE for the angular data. The concept of the tie-point zones and the quadratic interpolation schema with coefficients analytically derived from the scanning geometry forms the main elements of the method presented. The full algorithm and mathematical background needed are presented, and the algorithm can be highly parallelized. The method can likely be applied to any cross-track scanning sensor.

Design of a compact high gain printed octagonal array of spiral-based fractal antennas for DBS application

AbstractThis paper presents a compact octagonal array of microstrip patch antennas for direct broadcast satellite (DBS) (12.2–12.7 GHz) services. The proposed single element of this array is a new fractal antenna, having considerably high gain and can heavily suppress cross polarization along the main beam direction. The single element is derived from a 2D spiral geometry. The corporate feed network of the array is designed in such a manner to make the structure very compact. The fabricated single element resonates at 12.51 GHz and gives a gain and bandwidth of 9.32 dBi and 280 MHz, respectively. The array resonates at 12.46 GHz and gives gain of 17.67 dBi and a bandwidth of 506 MHz, which ensures a 100% coverage of the entire DBS service band. The measured cross polarization of single element and array along the direction of main beam are −45.50 and −43.35 dB, respectively. Both the single element as well as the array maintains a reasonably good radiation efficiency of 86.70 and 82.20%, respectively.

Passive Bistatic Sea Clutter Statistics From Spaceborne Illuminators

The ability to use external illuminators of opportunity will be an important feature for future maritime radar systems. This article considers passive bistatic radar operation using the Sirius-XM and Optus-D3 broadcast satellites. These operate in different frequency bands and with different bistatic geometries and bandwidths. In order to evaluate radar detection performance, generate realistic sea clutter, and develop suitable detection schemes, we require an understanding of the sea clutter statistics. For the data studied here, we consider both the delay-Doppler and time-Doppler domains and include an analysis of the amplitude distribution, temporal correlation, and Doppler spectrum.

A two-individual based path-relinking algorithm for the satellite broadcast scheduling problem

Population-based metaheuristic algorithms normally manage a large number of ‘individuals’ to achieve diversity in the search process, which in turn lead to good quality solutions. Although the quality of the solutions produced by these algorithms is observed to be good for a variety of combinatorial optimization problems, managing a large number of individuals within the algorithm is often complex and time-consuming. In this paper, we develop a two-individual based path relinking (TPR) algorithmic framework harnessing the power of the solution-based tabu search and that of a distance-controlled relinking operator to solve the satellite broadcast scheduling problem (SBSP). The results of extensive computational experiments carried out demonstrate that our TPR algorithm outperforms state-of-the-art heuristic algorithms for SBSP with respect to various performance metrics, in a statistically significant way. The aim of this study is to compare the two-individual based search algorithm with the traditional population-based metaheuristic methods in the literature for the SBSP (i.e., ant colony optimization and differential evolution variant algorithms) to provide a highly competitive algorithm for solving this important practical problem with numerous applications, and to promote research on two-individual based search method, which received very little attention in the literature. Our results underscore that the two-individual based search algorithmic framework is a viable alternative for solving complex optimization problems and reconfirm the validity of analogous observations made by other researchers in the context of graph coloring and flexible job shop scheduling.

Low-Cost and Low-Profile Phased Array Antenna for Satellite Reception Using Optimized Tracking Algorithm

In this paper, a stair-planar phased array antenna system for mobile broadcast satellite reception in Ku-band is proposed. The hybrid electromechanical tracking algorithm of this antenna system is designed for properly steering the antenna beam into the target satellite. The antenna sub-array elements are designed by using FR-4 epoxy and RO4003 to reduce the fabrication cost without considerable drop in the array efficiency. The genetic algorithm optimization is used to achieve the optimum values for the element spacing and feed positions, also. This array is fabricated, tested and compared with the simulation results to prove the idea. After that, the selected array is expanded to the main sub-array (2 × 32) and the main antenna array composed of 640 microstrip elements (10 main sub-arrays with 64 elements in each sub-array) with 32.5-dB gain at operating frequency, 11.9 GHz. This system can cover 30°–70° in elevation and 360° in azimuth planes by using the hybrid tracking algorithm to track different target satellites. This system serves as an excellent low-cost and simple candidate for Ku-band satellite reception in steady and smoothly moving platforms such as trains.

Delivering Standards to Industries: The MPEG Case [Standards in a Nutshell

Delivering products, services, and applications to the masses is a problem that more companies face every day in a globalized economy. Imagine what the problem was like 30 years ago when the delivery of media content was a reality but had been achieved by providing solutions that applied to specific media types, delivery methods, countries, regions, industries, and companies. Telecommunication companies distributed music; cable operators distributed TV via cable; terrestrial and satellite broadcasters did the same through terrestrial and satellite networks; and different types of businesses distributed all sorts of recorded media on physical support (film, laser discs, compact cassettes, Video Home System/Betamax cassettes, and so forth).

Competition between Cable Television and Direct Broadcast Satellite - It's More Complicated than You Think

Direct Broadcast Satellite (DBS) is often considered a substitute for basic cable service, but current cable subscribers may face substantial switching costs to move from cable to DBS services. We use aggregate firm-level price data and other related demographic variables to examine the cost of switching from cable to DBS and vice versa. We find some firm-specific attributes and demographic variables that influence consumer choice and switching costs that appear to affect consumers' desire to switch from one service to another. We then use observation-specific dummy variables that stratify cable price based on changes in the level of cable prices between two periods to examine whether consumer behavior varies depending on the size of price change. We find that when quality-adjusted prices for basic cable services increase substantially, subscribers will switch from cable to DBS, presumably at the point at which the price change is larger than the cost of switching.