Tracking And Data Relay Satellite Research Articles

An on‐orbit calibration method for time delay of inter‐satellite link transponder in tracking and data relay satellite

AbstractThe tracking and data relay satellite (TDRS) in geosynchronous orbit (GEO) can provide ranging and communication services for user spacecraft in low Earth orbit (LEO) through the inter‐satellite link (ISL). The time delay of TDRS ISL transponder in orbit differs from its pre‐launch state and changes due to the complex space environment, adding significant errors to the user spacecraft's orbit determination based on four‐way ranging data. The authors have developed a calibration system and proposed an efficient on‐orbit calibration method for the ISL transponder's time delay in TDRS. Experimental results demonstrate the effectiveness of the authors’ method, and the RMS of calibration residuals is less than 0.5 m.

Unlocking higher data volumes from space to Earth: A boost to scientific experiments on board space stations

This paper presents a novel strategy to download higher data volumes from space stations. To demonstrate this approach, the communication link between the international space station (ISS) and the U.S. tracking and data relay satellite (TDRS) system is considered. The proposed solution relies on multiple-antenna technology, so-called multiple-input multiple-output, that can provide added capacity gain if the antenna elements match a precise geometry. The analysis shows that two colocated TDRSs can lead to a capacity increase by a factor of 1.8 per polarization per satellite. We compare this approach to other enhancement strategies. This study shows that the proposed solution presents the best trade-off in terms of capacity increase, link availability, redundancy and system changes. Thus, this paper provides a novel perspective on potential future space data relay, which leads to high benefits in the near term to customers like the ISS and the high data volume required from the on-board scientific experiments.

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Task Scheduling Method for Data Relay Satellite Network Considering Breakpoint Transmission

The increasing demands for space-based data transmission pose a great challenge to task scheduling of tracking and data relay satellites (TDRSs). In order to improve the working efficiency and task completion rate of the data relay satellite network (DRSN), for the first time, we propose a novel application mode for DRSN, in which data breakpoint transmission is considered. In the mode of data breakpoint transmission, a single task can be reasonably split into multiple subtasks and thus scheduled in multiple time windows. At first, the task scheduling model of DRSN considering breakpoint transmission is defined. In addition, a two-stage method is designed to generate a high-quality initial solution. Moreover, we propose an adaptive variable neighborhood descent combined with a tabu list (AVND-TL) to iteratively improve the initial solution. In AVND-TL, two task reallocation neighborhood structures are incorporated and adaptively selected during the solution search process, which effectively prevent the algorithm from falling into local optimum. Finally, extensive experiments are carried out to verify that the proposed breakpoint transmission mode and AVND-TL together can significantly improve the task completion rate and resource utilization rate.

Communications satellites: Time expanded graph exploration of a tradespace of architectures

The choice of architecture in the design of large-scale complex systems has an enormous bearing on the cost, performance and adaptability of the system. It is often the case that the operational environment of the system changes over time, necessitating evolution of the architecture. In this paper, tradespace graphs of candidate space-based relay networks for NASA׳s Space Communication and Navigation (SCaN) program, focusing on the Tracking and Data Relay Satellite (TDRS) system, are analyzed in order to examine the potential pathways through the tradespace for a specified planning horizon. We utilize a method that enumerates architectures as vertices in a tradespace graph, taking into account both the fixed properties of the architecture and the variable ages of its assets. We then examine what real options can be put in place to enable future flexibility given uncertainty about the lifespan of existing TDRS assets. In a separate set of analysis, these time-expanded graphs are used to price the potential inclusion of hosted payloads against a range of possible architectural decisions.

Adaptive subsequence adjustment with evolutionary asymmetric path-relinking for TDRSS scheduling

Due to the limited transmission resources for data relay in the tracking and data relay satellite system (TDRSS), there are many job requirements in busy days which will be discarded in the conventional job scheduling model. Therefore, the improvement of scheduling efficiency in the TDRSS can not only help to increase the resource utilities, but also to reduce the scheduling failure ratio. A model of nonhomogeneous parallel machines scheduling problems with time window (NPM-TW) is firstly built up for the TDRSS, considering the distinct features of the variable preparation time and the nonhomogeneous transmission rates for different types of antennas on each tracking and data relay satellite (TDRS). Then, an adaptive subsequence adjustment (ASA) framework with evolutionary asymmetric path-relinking (EvAPR) is proposed to solve this problem, in which an asymmetric progressive crossover operation is involved to overcome the local optima by the conventional job inserting methods. The numerical results show that, compared with the classical greedy randomized adaptive search procedure (GRASP) algorithm, the scheduling failure ratio of jobs can be reduced over 11% on average by the proposed ASA with EvAPR.

A hybrid multiuser detector based on MMSE and AFSA for TDRS system forward link.

This study mainly focuses on multiuser detection in tracking and data relay satellite (TDRS) system forward link. Minimum mean square error (MMSE) is a low complexity multiuser detection method, but MMSE detector cannot achieve satisfactory bit error ratio and near-far resistance, whereas artificial fish swarm algorithm (AFSA) is expert in optimization and it can realize the global convergence efficiently. Therefore, a hybrid multiuser detector based on MMSE and AFSA (MMSE-AFSA) is proposed in this paper. The result of MMSE and its modified formations are used as the initial values of artificial fishes to accelerate the speed of global convergence and reduce the iteration times for AFSA. The simulation results show that the bit error ratio and near-far resistance performances of the proposed detector are much better, compared with MF, DEC, and MMSE, and are quite close to OMD. Furthermore, the proposed MMSE-AFSA detector also has a large system capacity.

Zenith Pass Problem of Inter-satellite Linkage Antenna Based on Program Guidance Method

While adopting an elevation-over-azimuth architecture by an inter-satellite linkage antenna of a user satellite, a zenith pass problem always occurs when the antenna is tracing the tracking and data relay satellite (TDRS). This paper deals with this problem by way of, firstly, introducing movement laws of the inter-satellite linkage to predict the movement of the user satellite antenna followed by analyzing the potential pass moment and the actual one of the zenith pass in detail. A number of specific orbit altitudes for the user satellite that can remove the blindness zone are obtained. Finally, on the base of the predicted results from the movement laws of the inter-satellite linkage, the zenith pass tracing strategies for the user satellite antenna are designed under the program guidance using a trajectory preprocessor. Simulations have confirmed the reasonability and feasibility of the strategies in dealing with the zenith pass problem.

Coordinated attitude control for a tracking and data relay satellite with mobile antennas

In this paper, a coordinated attitude control law for a tracking and data relay satellite (TDRS) with mobile antennas is proposed. To track or point the target spacecraft with median/law orbit, the large mobile antennas have to move in a wide range, the movement of such mobile antennas disturbing the satellite attitude. Conventionally, the main body of the satellite and the mobile antennas are controlled independently. The proposed controller first estimates the TDRS's angular momentum which the mobile antennas will produce, based on the momentum conservation equation, then adds the estimated angular momentum as a feedforward signal to the conventional control law. The proposed controller is demonstrated using mathematical simulation, the results of which coincide well with analytical results.

Multimedia satellite communications experiments to the international space station

AbstractIn the present concept of the International Space Station ISS, it is planned to provide the communication services between the European Columbus module of the ISS and the ground equipment via the TDRS (tracking and data relay satellite) network provided by the American NASA (National Aeronautics and Space Agency). Especially because of its low uplink data rate, an unacceptable limitation of the communication services with Columbus is to be expected.In order to investigate possible improvements to this situation, the MEDIS proposal studies the feasibility of a 150 Mbps full duplex communication system to the Columbus Module on via two MEO satellites. A mixed topology with optical inter satellite links and Ka‐band up/down‐links shall be employed. Also possible liaisons with the Artemis mission will be considered.The MEDIS project is a collaboration of Astrium GmbH, which is project manager, Bosch SatCom, GMD‐Fokus and the German Aerospace Center (DLR). The preparation phase of the project will investigate the concept of the communications infrastructure and the experiments that could be realized when the MEOs are launched. This stage has been completed in February 2001. An additional study phase followed, which will be completed with a presentation in July 2002.Briefly the following aspects have been studied by DLR in the preparation phase: the overall concept of experimental communication services for Columbus, the system requirements and network topology, the relevant protocol and hardware architectures, useful satellite constellations and link scenarios. Two phases could follow the preparation phase, in phase one the satellite will be launched and the link will be tested. In phase two the satellites will be connected to the ISS. Copyright © 2002 John Wiley & Sons, Ltd.

Result of Remote Pilot Rendezvous Experiment by ETS-VII.

Engineering Test Satellite-VII (ETS-VII) is the test satellite to demonstrate and verify rendezvous docking technology. After success in an autonomous rendezvous docking in the 1st and 2nd experiment flights in 1998, we performed remote pilot rendezvous experiment by ETS-VII in Oct. 1999. In the experiment, ETS-VII was controlled by a ground pilot via Tracking and Data Relay Satellite (TDRS). To overcome long time delay and poor information on thruster acceleration, the ground pilot predicted the changes of position and velocity after thruster firing, and controlled the Chaser satellite. In this paper, we present the result and evaluation of the remote pilot experiment. It could be shown that remote pilot was very useful to control rendezvous spacecraft with long time delay and/or with unknown control characteristics.

Analysis of solar degradation to TDRS S-band phased array antenna

A study of the distribution of gain-to-noise-temperature (G/T) values for the Tracking and Data Relay Satellite (TDRS) satellite is described. The statistics of the G/T values are determined by a Monte Carlo simulation of the orbital geometry of the Sun and Moon, and the gain and noise temperature calculations is included. The results and their underlying assumptions are described.

Enhanced Radiative Force Modeling of the Tracking and Data Relay Satellites

Orbit determination (OD) approaches operationally model the Tracking and Data Relay Satellites (TDRS) as homogenous spheres for nonconservative force modeling. To improve definitive orbit determination and prediction accuracies, and to employ TDRSS tracking of user satellites within various geophysical investigations, a detailed TDRS spacecraft model has been developed. The enhanced TDRS model represents the spacecraft as a combination of twenty-four flat plates. The radiative forces acting on each plate are computed and vector summed to produce the overall acceleration on the spacecraft center of mass. An initial model, based on pre-launch engineering information, has been refined to better fit observed spacecraft accelerations. The Goddard TDRS-5 Model 3 (GT5M3) improves orbit accuracy, yields better fits to the tracking data, significantly reduces residual accelerations, and improves orbit prediction capability.

Space Shuttle Precision Orbit Determination in Support of SLA-1 Using TDRSS and GPS Tracking Data

On January 11, 1996, the Space Shuttle Endeavor, mission STS-72, was launched, carrying aboard the first of four Shuttle Laser Altimeter (SLA) experiments. In support of SLA-1, precise orbits have been computed from Tracking and Data Relay Satellite System (TDRSS) Doppler observations. In some cases, these data were combined with Global Positioning System (GPS) pseudorange observations. Traditionally, the Tracking and Data Relay Satellite (TDRS) orbits themselves have been the dominant source of error in Shuttle orbit determination during quiescent attitude periods. However, a new technique utilizing TOPEX/Poseidon’s (T/P) precise orbit knowledge plus the TDRSS-T/P Doppler tracking is used to significantly reduce the TDRS orbit errors. That approach, along with improved modeling and parameterization have allowed us to compute precise Shuttle orbits from TDRSS-Shuttle Doppler tracking data. Orbit overlap comparisons indicate these Doppler-derived orbits have a meter level (1σ) radial precision, and they agree radially with the combined Doppler and GPS derived orbits at the 1.5 m level (1σ).

Orbit determination of TOPEX/POSEIDON and TDRSS satellites using TDRSS and BRTS tracking

TOPEX/POSEIDON (TP) orbits were computed from measurements taken by the US Tracking and Data Relay Satellite (TDRS) System (TDRSS). TP orbits can be computed from TDRSS tracking with an accuracy on the order of 10 cm in the radial direction and 20 cm in absolute position if the orbits of the TDRSs are known with high accuracy. Orbits of TDRSs can be determined with an estimated accuracy significantly better than 10 m in the radial direction, and 20 m in absolute position, if the high-accuracy TP orbits from SLR/DORIS tracking are used as constraints in orbit computations of the TDRSs, and use is made of TP tracking data by TDRSS. If the orbits of TP and the TDRSs are estimated together from both TDRSS tracking data and data acquired by the Bilateration Ranging Transponder (BRT) System (BRTS) and no a priori information is used, these accuracy levels are 25 cm and 2–5 m for TP, and 10 m and 20–30 m for the TDRSs, respectively. Orbits of the TDRSs can be computed with an accuracy of 10 m in the radial direction and 30–40 m in absolute position if only BRTS tracking data is used. Finally, maneuvers of TDRSs and TP have been estimated with high accuracy from BRTS and TDRSS tracking data.

Potential future applications for the Tracking and Data Relay Satellite II (TDRS II) system

During the conceptual design phases of the tracking and data relay satellite (TDRS) II system provision was made for a future service growth (FSG) payload with an undefined mission. The intent of the FSG was to provide a resource for TDRS II applications which would be available to meet a change in requirements for the operational TDRS II system. This paper summarizes the effect of the consideration of potential FSG applications imposed on the tracking and data relay satellite (TDRS) II system.The following applications were considered as FSG candidates: • • An optical 650 Mbps space-to-space link (SSL) coupled to an optical or RF downlink [1] • • An RF or optical crosslink to extend the baseline TDRS II system coverage —zone of exclusion (ZOE) closure [1] • • Relay for lunar communications either RF or optically • • Relay for Martian communications either RF or optically This paper summarizes work done in the 1990 time frame on the above stated applications. Since then, NASA has sponsored several studies (during phase B of the TDRS II development cycle) of the ZOE closure application of the FSG. The purpose of this paper is to report on the efforts previously considered for the FSG. A previous paper was presented at the 1991 Congress related to the second application above. This paper extends this effort to the four stated applications.

Overview of TDRSS

The National Aeronautics and Space Administration (NASA) has developed the Tracking and Data Relay Satellite (TDRS) System (TDRSS) for operational tracking and communications support of low Earth-orbiting satellites. TDRSS currently consists of five geosynchronous spacecraft and the White Sands Complex (WSC) at White Sands, New Mexico. The Bilateration Ranging Transponder (BRT) System (BRTS) supports range and Doppler measurements for each TDRS using standard user tracking services. These measurements are used to generate well-determined ephemerides for the TDRSs. TDRSS provides S-band and Ku-band services through the single access (SA) antennas and S-band services through the S-band multiple access (SMA) phased array. TDRSS is capable of supporting coherent range and two-way Doppler tracking as well as noncoherent one-way return-link and one-way forward-link Doppler tracking of user spacecraft. Accurate one-way return-link tracking, which can use SMA, the most available TDRSS resource, requires a stable oscillator onboard the user spacecraft as the source of frequency. Two-way and one-way return-link tracking measurements are used for ground orbit determination for navigation and precise positioning; one-way forward-link tracking is used for autonomous onboard navigation with achievable accuracies better than those of the Global Positioning System (GPS) Precise Positioning System (PPS). This overview will discuss the various tracking and navigation capabilities of TDRSS, as well as many of the operational and research applications that have been conducted for missions such as Landsat-4, Ocean Topography Experiment (TOPEX)/Poseidon (T/P), Cosmic Background Explorer (COBE), and Extreme Ultraviolet Explorer (EUVE).

Landsat-4 orbit determination using TDRSS

This paper presents the results of a study to compare the orbit determination accuracy for a Tracking and Data Relay Satellite (TDRS) System (TDRSS)-user spacecraft, Landsat-4, obtained using a Prototype Filter Smoother (PFS), with the accuracy of an established batch-least-squares system, the Goddard Trajectory Determination System (GTDS). The results of Landsat-4 orbit determination provide useful experience for the Earth Observing System (EOS) series of satellites. The filtered and smoothed PFS orbit solutions were compared with the definitive GTDS orbit solutions for Landsat-4; the root-mean-square (RMS) solution difference was 6.6 meters.

Autonomous navigation using the TDRSS Onboard Navigation System (TONS)

The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) is currently developing a Tracking and Data Relay Satellite (TDRS) System (TDRSS) Onboard Navigation System (TONS) to provide onboard knowledge of highly accurate navigation products autonomously to users of TDRSS. The TONS I operational system processes Doppler data derived from scheduled forward-link S-band services to provide onboard orbit and frequency determination and time maintenance. TONS I is implemented using a stable onboard frequency reference, a Doppler measurement capability in the user transponder, and onboard navigation/signal acquisition software. The success of the TONS experiment (1992/1993), which was implemented on the Explorer Platform/Extreme Ultraviolet Explorer (EP/EUVE) spacecraft, demonstrated the flight readiness of TONS I. TONS II-A provides the user with additional Doppler data derived from an S-band beacon signal, available approximately 80 percent of the time. This paper describes the TONS operational capabilities, configurations, and expected performance.

Accuracy assessment of TDRSS-based TOPEX/Poseidon orbit determination

Orbit determination results are obtained for the Ocean Topography Experiment (TOPEX)/Poseidon spacecraft by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) using a batch-least-squares estimator available in the Goddard Trajector Determination System (GTDS) to process Tracking and Data Relay Satellite (TDRS) System (TDRSS) measurements. The GTDS orbit solutions are compared with the definitive Precision Orbit Determination (POD) orbit solutions. The root-mean-square (RMS) solution difference in the radial component is 28 centimeters.