A Review on Precise Orbit Determination of Various LEO Satellites

The need for precise orbit determination (POD) has grown significantly due to the increased amount of space-based activities appearing at an accelerating pace. POD has a positive contribution in achieving the requirements of Low-Earth Orbit (LEO) satellite mission which includes improved reliability and continuity. In this paper, we will review the POD approaches of various LEO satellites and discuss the accuracy levels obtained as well as the methods and algorithms used to achieve the POD of LEO satellites. With recent advancements in miniature space technology, a greater number of smaller low-cost satellites are launched into the LEO for various purposes. Furthermore, development in the Global Navigation Satellite Systems (GNSS) and chipsets played a vital role in revolutionizing the GNSS receiver technology. Lower-cost, smaller size but yet high performing GNSS receivers need to be implemented also in CubeSats in addition to the various terrestrial applications. POD using onboard GNSS receiver data will benefit the development of several upcoming space applications in the field of navigation systems, telecommunication, remote sensing, and earth observation. In the future, it is anticipated that LEO-based satellites enabled by POD can also offer positioning capabilities that will enhance GNSS and create vast opportunities for users with new features and possibilities to the navigation field.© 2021 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0). CEUR Workshop Proceedings (CEUR-WS.org)fi=vertaisarvioitu|en=peerReviewed

Precise orbit determination of LEO satellites : a systematic review

The need for precise orbit determination (POD) has grown significantly due to the increased amount of space-based activities taking place at an accelerating pace. Accurate POD positively contributes to achieving the requirements of Low-Earth Orbit (LEO) satellite missions, including improved tracking, reliability and continuity. This research aims to systematically analyze the LEO–POD in four aspects: (i) data sources used; (ii) POD technique implemented; (iii) validation method applied; (iv) accuracy level obtained. We also present the most used GNSS systems, satellite missions, processing procedures and ephemeris. The review includes studies on LEO–POD algorithms/methods and software published in the last two decades (2000–2021). To this end, 137 primary studies relevant to achieving the objective of this research were identified. After the investigation of these primary studies, it was found that several types of POD techniques have been employed in the POD of LEO satellites, with a clear trend observed for techniques using reduced-dynamic model, least-squares solvers, dual-frequency signals with undifferenced phase and code observations in post-processing mode. This review provides an understanding of the various POD techniques, dataset utilized, validation techniques, and accuracy level of LEO satellites, which have interest to developers of small satellites, new researchers and practitioners.© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.fi=vertaisarvioitu|en=peerReviewed

Autonomous integrated GPS/INS navigation experiment for OMV. Phase 1: Feasibility study

The phase 1 research focused on the experiment definition. A tightly integrated Global Positioning System/Inertial Navigation System (GPS/INS) navigation filter design was analyzed and was shown, via detailed computer simulation, to provide precise position, velocity, and attitude (alignment) data to support navigation and attitude control requirements of future NASA missions. The application of the integrated filter was also shown to provide the opportunity to calibrate inertial instrument errors which is particularly useful in reducing INS error growth during times of GPS outages. While the Orbital Maneuvering Vehicle (OMV) provides a good target platform for demonstration and for possible flight implementation to provide improved capability, a successful proof-of-concept ground demonstration can be obtained using any simulated mission scenario data, such as Space Transfer Vehicle, Shuttle-C, Space Station

Single-Frequency GPS Relative Navigation in a High Ionosphere Orbital Environment

The Global Positioning System (GPS) provides a convenient source for space vehicle relative navigation measurements, especially for low Earth orbit formation flying and autonomous rendezvous mission concepts. For single-frequency GPS receivers, ionospheric path delay can be a significant error source if not properly mitigated. In particular, ionospheric effects are known to cause significant radial position error bias and add dramatically to relative state estimation error if the onboard navigation software does not force the use of measurements from common or shared GPS space vehicles. Results from GPS navigation simulations are presented for a pair of space vehicles flying in formation and using GPS pseudorange measurements to perform absolute and relative orbit determination. With careful measurement selection techniques relative state estimation accuracy to less than 20 cm with standard GPS pseudorange processing and less than 10 cm with single-differenced pseudorange processing is shown

ORBIT PROPAGATION AND DETERMINATION ALGORITHMS FOR SATELLITE GROUND STATIONS

The satellite orbital parameters are essential for satellite operations. With these parameters, it is possible to estimate the satellite position in the recent past and near future, which is essential to effectively plan satellite operations and associate satellite telemetry with geographical locations.However, for small or medium satellite operators who do not possess the infrastructure required to track their satellites, the problem of determining the satellite orbit is problematic. To access the orbit for their satellites, these organizations have to rely on third parties such as Celestrak. These entities provide the service free of charge but do not provide orbital parameters with the required frequency. Furthermore, another problem may arise during the mission\u27s early phases. Suppose the satellite is launched together with a number of other satellites, as is often done for small satellites. In that case, it is also not known in the first days or weeks of the mission which orbital parameters are from which satellite launched in the group. This project aims to address the problem of orbital parameter determination by using GPS data, Kalman filters and AI (genetic algorithm)

Introduction to Navigation Systems

Navigation is the method for determining position, speed, and direction of the object. That is mainly classified into two groups: physical model-based methods (PMMs) and external data-based methods (EDMs). Examples of PMMs are inertial navigation systems (INS) and dead-reckoning navigation. They determine the existing position of an object by measuring various changes in its state, such as velocity and acceleration. Representative EDMs is the global navigation satellite system (GNSS). In the case of spacecraft, auxiliary navigation systems using data compression were proposed. In the case of low earth orbit satellites, the deviations between nominal and real orbit are compressed in the form of Fourier coefficients by using the periodic characteristics of the trajectory. In the event of Deep space explorer, B-spline based orbit compression and transmission was proposed

Decentralized Control of Electromagnetic ChipSat Swarm Formations

Small satellite formation missions offer new options for space exploration and scientific experiments. Groups of satellites flying within short relative distances allow various important applications, such as spatially distributed instruments for atmospheric sampling or remote sensing systems. The ability to independently control the relative motion of each satellite is crucial to establish a swarm formation, using a large number of satellites moving along bounded relative trajectories. This type of mission poses several constraints on mass, size, and energy consumption; therefore, an autonomous and selfsufficient approach is necessary to assure relative motion control. A novel concept of miniaturized satellites, referred to as ChipSats, consists of a single printed circuit board which can be equipped with different sets of microelectronic components including power and communication systems, a variety of sensors, and a microcontroller. This study considers a swarm of ChipSats equipped with magnetorquers, operating at extremely short relative distances, and using the electromagnetic interaction force for relative motion and attitude control, assuming the absolute position and relative state of each unit is known. Despite the limitations imposed by using magnetorquers as the sole actuators onboard, the dipole interaction between drifting satellites can be used to achieve bounded relative trajectories, and to establish and maintain a compact swarm. Following a decentralized approach, the ChipSats are periodically linked in interchangeable pairs in order to apply the Lyapunov-based control algorithm and prevent relative drift between all satellites in the swarm. The magnetic dipole moments are used for angular velocity damping when orbit control is not required, and a repulsive collision avoidance electromagnetic control force is applied when two ChipSats are within dangerously close proximity to each other. The performance assessment is conducted through Monte Carlo simulations using MATLAB, by analyzing operational parameters and the effect of initial conditions after deployment.Formações de pequenos satélites oferecem novas opções para exploração espacial e experiências científicas. Grupos de satélites, operando a curtas distâncias relativas, possibilitam importantes aplicações tais como instrumentação espacialmente distribuída para amostragem atmosférica ou sistemas de sensoriamento remoto. A capacidade de controlar de forma independente o movimento de cada satélite é crucial para establecer uma formação em enxame, utilizando um grande número de satélites movendo-se ao longo de trajetórias relativas limitadas. Este tipo de missão impõe várias restrições ao nível do consumo de energia, da massa e do tamanho dos satélites, consequentemente, é necessária uma abordagem autónoma e auto-sustentável para assegurar o controlo das trajetórias relativas. Um novo conceito de satélite miniatura, denominado ChipSat, consiste de uma única placa de circuito impresso que pode ser equipada com diferentes conjuntos de componentes microelectrónicos. Este estudo considera um enxame de ChipSats equipados com magnetorquers, operando a distâncias relativas extremamente reduzidas, e usando a força de interação eletromagnética para controlo do movimento relativo e orientação dos satélites, assumindo que a posição absoluta e relativa de cada unidade é conhecida. Apesar das limitações impostas por usar os magnetorquers como únicos atuadores a bordo, a interação magnética dipolar pode ser usada para limitar trajetórias relativas e establecer um enxame compacto. Seguindo uma abordagem descentralizada, os ChipSats são periodicamente ligados em pares intermutáveis de modo a aplicar o algoritmo de control baseado no teorema de Lyapunov, impedindo o aumento da distância relativa entre todos os satélites no enxame. O momento magnético dipolar é usado para amortecimento da velocidade angular quando o control orbital não é necessário, e uma força eletromagnética repulsiva é usada para controlo de colisão quando dois ChipSats estão perigosamente próximos. A análise de performance é feita através de simulações Monte Carlo no MATLAB, estudando os parâmetros operacionais e o efeito das condições iniciais após o lançamento

Absolute and relative POD of LEO satellites in formation flying: Undifferenced and uncombined approach

Absolute or relative precise orbit determination (POD) is an essential prerequisite for many low earth orbit (LEO) missions. The POD of LEO satellites typically relays on processing the onboard global navigation satellite system (GNSS) measurements. The absolute POD is usually based on an ionosphere-free (IF) combination, and currently, integer ambiguity resolution (IAR) can be achieved only when external GNSS satellite phase bias (SPB) products are used. The use of these products is not flexible in multi-frequency/multi-constellation scenarios and is difficult to achieve in real-time missions. For relative POD, the double-differenced (DD) with IAR is the most general method. However, the differencing process amplifies observation noise and loses the opportunity to impose dynamic constraints on some eliminated parameters. In this contribution, based on the use of undifferenced and uncombined (UDUC) observations, a new model for both absolute and relative POD is proposed. In this model, the ambiguities of common-view satellites are constructed into DD form, thus IAR can be achieved without any external SPB products. Working with the UDUC observations, multi-frequency scenarios can be easily applied, and residuals can be separated for each frequency. In addition, with precise GNSS satellite clock/orbit products, both the absolute and relative orbits can be derived, which supports absolute and relative LEO POD. Based on onboard GPS observations of T-A and T-B satellites in formation flying, the performance of the UDUC POD model with DD ambiguity was evaluated. With the UDUC algorithm and IAR, the proposed model presented a consistency of 2.8–3.8 cm in 3D with the reference orbits, and the orbit difference was reduced by 16.3% and 10.6% for T-A and T-B compared with the IF-based POD, respectively. In addition, the relative orbit of the two satellites derived from the proposed model showed a consistency of 1.1–1.5 mm, which proved the feasibility of the UDUC POD model with DD ambiguity for formation flying missions

Orbit Estimation Using a Horizon Detector in the Presence of Uncertain Celestial Body Rotation and Geometry

This paper presents an orbit estimation using non-simultaneous horizon detector measurements in the presence of uncertainties in the celestial body rotational velocity and its geometrical characteristics. The celestial body is modelled as a tri-axial ellipsoid with a three-dimensional force field. The non-simultaneous modelling provides the possibility to consider the time gap between horizon measurements. An unscented Kalman filter is used to estimate the spacecraft motion states and estimate the geometric characteristics as well as the rotational velocity of the celestial body. A Monte-Carlo simulation is implemented to verify the results. Simulations showed that using non-simultaneous horizon vector measurements, the spacecraft state errors converge to zero even in the presence of an uncertain geometry and rotational velocity of the celestial body.Comment: 17 pages, 7 figures, accepted for publication in Acta Astronautic