Design and Operation of the GPS Receiver Onboard the CanX-2 Nanosatellite

Kahr, Erin; Bradbury, Laura; O’Keefe, Kyle; Skone, S.

doi:10.1002/navi.36

Cited by 4 publications

(12 citation statements)

References 14 publications

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“…Others have taken a New Space approach to GNSS-RO, one characterized by nanosatellites and Commercial-Off-The-Shelf (COTS) components. In 2008, the 3U cubesat known as the Canadian Advanced Nanosatellite eXperiment-2 (CANX-2) mission was launched with a COTS GPS receiver to perform just such an experiment [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

GNSS Radio Occultation on Aerial Platforms with Commercial Off-The-Shelf Receivers

Chan¹,

Goel²,

Kosh³

et al. 2021

Preprint

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In recent decades, GNSS Radio Occultation soundings have proven an invaluable input to global weather forecasting. The success of government-sponsored programs such as COSMIC is now complemented by commercial low-cost cubesat implementations. The result is access to more than 10,000 soundings per day and improved weather forecasting accuracy. This movement towards commercialization has been supported by several agencies, including the National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA) and the U.S. Air Force (USAF) with programs such as the Commercial Weather Data Pilot (CWDP). This has resulted in further interest in commercially deploying GNSS-RO on complementary platforms. Here, we examine a so far underutilized platform: the high-altitude weather balloon. Such meteorological radiosondes are deployed twice daily at over 900 locations globally and form an essential in-situ data source as a long-standing input to weather forecasting models. Adding GNSS-RO capability to existing radiosonde platforms would greatly expand capability, allowing for persistent and local area monitoring, a feature particularly useful for hurricane and other severe weather monitoring. A prohibitive barrier to entry to this inclusion is cost and complexity as GNSS-RO traditionally requires highly specialized and sensitive equipment. This paper describes a multi-year effort to develop a low-cost and scalable approach to balloon GNSS-RO based on Commercial-Off-The-Shelf (COTS) GNSS receivers. We present hardware prototypes and data processing techniques which demonstrate the technical feasibility of the approach through results from several flight testing campaigns.

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Section: Introductionmentioning

confidence: 99%

GNSS Radio Occultation on Aerial Platforms with Commercial Off-The-Shelf Receivers

Chan¹,

Goel²,

Kosh³

et al. 2021

Preprint

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“…In addition to the two-line elements (TLEs), other sensors like sun sensors and magnetometers have been used for orbit determination of CubeSats with relatively low accuracy, i.e., at km-level [19]. In the case of higher positioning accuracy requirements, the GNSS-based processing has been demonstrated as a useful method for the CubeSat POD, for which successful postprocessed position fix was achieved with a meter-level accuracy [20]. While the onboard positioning normally utilizes simplified dynamic models due to the limitation of the computational load [21,22], the data postprocessing allows the usage of comprehensive dynamic models and the estimation of enough additional dynamic parameters to compensate remaining model deficiencies.…”

Section: Introductionmentioning

confidence: 99%

“…The capacity for data tracking, storage, and transfer is thus restricted, which limits the accuracy of orbit determination. The GNSS satellites may not be able to be fully tracked continuously due to these limitations, which could yield a duty-cycle smaller than 100% [20,21,23], and lead to fewer data available for the processing and more ambiguities to be set up. The size of the data collected between each data dump could also be limited [20].…”

Section: Introductionmentioning

confidence: 99%

A Sensitivity Study of POD Using Dual-Frequency GPS for CubeSats Data Limitation and Resources

et al. 2020

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Making use of dual-frequency (DF) global navigation satellite system (GNSS) observations and good dynamic models, the precise orbit determination (POD) for the satellites on low earth orbits has been intensively investigated in the last decades and has achieved an accuracy of centimeters. With the rapidly increasing number of the CubeSat missions in recent years, the POD of CubeSats were also attempted with combined dynamic models and GNSS DF observations. While comprehensive dynamic models are allowed to be used in the postprocessing mode, strong constraints on the data completeness, continuity, and restricted resources due to the power and size limits of CubeSats still hamper the high-accuracy POD. An analysis of these constraints and their impact on the achievable orbital accuracy thus needs to be considered in the planning phase. In this study, with the focus put on the use of DF GNSS data in postprocessing CubeSat POD, a detailed sensitivity analysis of the orbital accuracy was performed w.r.t. the data continuity, completeness, observation sampling interval, latency requirements, availability of the attitude information, and arc length. It is found that the overlapping of several constraints often causes a relatively large degradation in the orbital accuracy, especially when one of the constraints is related to a low duty-cycle of, e.g., below 40% of time. Assuming that the GNSS data is properly tracked except for the assumed constraints, and using the International GNSS Service (IGS) final products or products from the IGS real-time service, the 3D orbital accuracy for arcs of 6 h to 24 h should generally be within or around 1 dm, provided that the limitation on data is not too severe, i.e., with a duty-cycle not lower than 40% and an observation sampling interval not larger than 60 s.

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“…There has been significant progress in the development, space qualification, and flight of miniaturized GPSRO sensors focusing on the ionosphere. In 2008, the first COTS sensor for GPSRO was flown on a nanosatellite, but unfortunately due to spacecraft issues, no occultation products were obtained [27]. The first successful demonstration of a GPSRO sensor on a nanosatellite occurred in 2011 with the launch of the PSSCT-2 mission [28].…”

Section: Mirata Gpsro Sensormentioning

confidence: 99%

Assessment of Radiometer Calibration With GPS Radio Occultation for the MiRaTA CubeSat Mission

Marinan

Cahoy

Bishop

et al. 2016

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Abstract-The microwave radiometer technology acceleration (MiRaTA) is a 3U CubeSat mission sponsored by the NASA Earth Science Technology Office. The science payload on MiRaTA consists of a triband microwave radiometer and global positioning system (GPS) radio occultation (GPSRO) sensor. The microwave radiometer takes measurements of all-weather temperature (Vband, 50-57 GHz), water vapor (G-band, 175-191 GHz), and cloud ice (G-band, 205 GHz) to provide observations used to improve weather forecasting. The Aerospace Corporation's GPSRO experiment, called the compact total electron content and atmospheric GPS sensor (CTAGS), measures profiles of temperature and pressure in the upper troposphere/lower stratosphere (∼20 km) and electron density in the ionosphere (over 100 km). The MiRaTA mission will validate new technologies in both passive microwave radiometry and GPSRO: 1) new ultracompact and low-power technology for multichannel and multiband passive microwave radiometers, 2) the application of a commercial off-the-shelf GPS receiver and custom patch antenna array technology to obtain neutral atmospheric GPSRO retrieval from a nanosatellite, and 3) a new approach to space-borne microwave radiometer calibration using adjacent GPSRO measurements. In this paper, we focus on objective 3, developing operational models to meet a mission goal of 100 concurrent radiometer and GPSRO measurements, and estimating the temperature measurement precision for the CTAGS instrument based on thermal noise Based on an analysis of thermal noise of the CTAGS instrument, the expected temperature retrieval precision is between 0.17 and 1.4 K, which supports the improvement of radiometric calibration to 0.25 K.

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Design and Operation of the GPS Receiver Onboard the CanX-2 Nanosatellite

Cited by 4 publications

References 14 publications

GNSS Radio Occultation on Aerial Platforms with Commercial Off-The-Shelf Receivers

GNSS Radio Occultation on Aerial Platforms with Commercial Off-The-Shelf Receivers

A Sensitivity Study of POD Using Dual-Frequency GPS for CubeSats Data Limitation and Resources

Assessment of Radiometer Calibration With GPS Radio Occultation for the MiRaTA CubeSat Mission

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