Ionospheric calibration for single frequency altimeter measurements

final report

Publisher: National Aeronautics and Space Administration, Publisher: National Technical Information Service, distributor in [Washington, DC, Springfield, Va

Written in English
Published: Downloads: 552
Share This


  • Ionosphere -- Research.,
  • Altimeter.

Edition Notes

StatementWilliam S. Schreiner, George H. Born.
Series[NASA contractor report] -- NASA CR-195709., NASA contractor report -- NASA CR-195709.
ContributionsBorn, George H., United States. National Aeronautics and Space Administration.
The Physical Object
Pagination1 v.
ID Numbers
Open LibraryOL14707583M

TOPEX/Poseidon makes altimetric sea level measurements using either the dual-frequency NASA ALT or the CNES single frequency SSALT. Since the ALT and the SSALT share a common antenna, they cannot be operated simultaneously. The ALT, the primary mission instrument, is operated about 90% of the time, and the SSALT is operated about 10% of the time. The single instrument frequency is GHz (Ku-band). SSALT is an experimental altimeter (of CNES, built by Alcatel Alenia Space, formerly Alcatel Espace, Toulouse) to demonstrate the concept of low-power, low-mass, low data rate (1/7 the rate ofNRA due to extensive on-board processing) and low-cost altimeter for future Earth observing missions. SENSOR Name: JASON-1 RADAR ALTIMETER (POSEIDON-2) Swath Width: km Description: The Poseidon-2 altimeter, operating at GHz (Ku band) and GHz (C band), is the primary sensor for the JASON-1 mission. The measurements made at the two frequencies are combined to obtain measurements of the altimeter range, wind speed, significant wave height, and the ionospheric . IEEE lntemational Frequency Control Symposium and PDA Exhibition IONOSPHERIC MODELS AND MEASUREMENTS FOR COMMON-VIEW TIME TRANSFER* , , and M. Jensen', E. Powers2, W. Klepczynski3, W. Lewandowski4 ' National Institute of Standards and Technology, Boulder CO, USA U.S. Naval Observatory, Washington, DC, USA Innovative Solutions International .

There is a principal possibility of calculating the ionospheric delay from the measurement data themselves made by the single frequency receiver. The possibility is based on the fact, that the correction for ionosphere in the code and phase measurements has opposite signs. Although such a. Single frequency receivers need to apply a model to remove the ionospheric refraction, which can reach up to few tens of meters, depending on the elevation of rays and the ionospheric conditions.. The models used in GPS and Galileo are described in Klobuchar Ionospheric Model and NeQuick Ionospheric GPS/Galileo satellites broadcast the parameters needed to run these ionospheric . Chen K, Gao Y () Ionospheric effect mitigation for real-time single-frequency precise point positioning. Navigation 55(3): Chen YQ, He XF () Contribution of pseudolite observations to GPS precise surveys. KSCE J. Civil Eng. 12(1): Computation of along-track sea level anomalies. From the raw altimeter measurement until the corrected SSH above a reference ellipsoid or the corresponding sea level anomaly (SLA) with respect to a known mean sea surface (MSS), the most common variable used in sea level studies, a number of corrections have to be applied to data, to account for the interactions with the atmosphere and.

Unlike T/P, the GFO altimeter is single frequency. Therefore, an ionospheric correction must be modeled or computed. Additionally, pre-launch analysis of temperature and voltage dependencies and return waveform effects as well as post-launch determination of corrections for seastate and attitude based on the calibrated waveform are required. The global ionospheric maps (GIMs), generated by Jet Propulsion Laboratory (JPL) and Center for Orbit Determination in Europe (CODE) during a period over 13 years, have been adopted as the primary source of data to provide global ionospheric correction for possible single frequency positioning applications. The investigation aims to assess the performance of new NeQuick model, NeQuick 2, in.

Ionospheric calibration for single frequency altimeter measurements Download PDF EPUB FB2

Ionospheric Calibration for Single Frequency Altimeter Measurements i" 1_ / William S. Schreiner George H. Born./ I # ' i ¢ r i Colorado Center for Astrodynamics Research Department of Aerospace Engineering Sciences University of Colorado, Boulder, CO Aug (NASA-CR) IONOSPHERIC CALIBRATION FOR SINGLE FREQUENCY.

An illustration of an open book. Books. An illustration of two cells of a film strip. Ionospheric calibration for single frequency altimeter measurements of the sub-satellite Total Electron Current (TEC) of the required accuracy (10 TECU rms) for the purpose of calibrating single frequency radar altimeter measurements.

The performance of PRISM is very promising for predicting TEC and will prove useful for calibrating single frequency altimeter height measurements for ionospheric path delay. Abstract. This report investigates the potential of using Global Positioning System (GPS) data and a model of the ionosphere to supply a measure of the sub-satellite Total Electron Current (TEC) of the required accuracy (10 TECU rms) for the purpose of calibrating single frequency radar altimeter by: 2.

The performance of the TOPEX dual-frequency altimeter ionosphere delay measurements has been evaluated by Imel () and Ruffini et al. Most historic altimeters were single-frequency (Ku.

However, the majority of these missions (Seasat, Geosat, ERS-1, ERS-2 and GFO-1) carry single-frequency (Ku band, GHz) altimeters. Consequently, unlike the case of the TOPEX/POSEIDON (T/P) dual-frequency altimeter, the ionospheric path delay for these satellite data cannot be directly removed from the altimeter range measurements.

Unlike with dual frequency altimeters the path delay due to the ionosphere cannot directly be removed from the altimeter range measurements. For a radar altimeter operating at a frequency of GHz, such as the one carried by GFO, this path delay can be greater than 20 cm at solar maximum or during ionospheric storms due to disturbed solar.

Ionospheric calibration for single frequency altimeter measurements. October (10 TECU rms) for the purpose of calibrating single frequency radar altimeter measurements.

The accuracy of single-frequency ocean altimeters benefits from calibration of the total electron content (TEC) of the ionosphere below the satellite. Data from a global network of Global Positioning System (GPS) receivers provides timely, continuous, and globally well-distributed measurements of ionospheric electron content.

product organization called International GNSS Service (IGS), which applications run from single frequency receivers (accurate mitigation of ionospheric delay), calibration of new altimeters (such as the SMOS mission) up to the potential use for increasing the performance of positioning based on carrier phase measurements.

single-site GPS data and is used to correct navigation radiomctric data for media effects. He continues to pursue efforts to improve the calibration system and validate its accuracy by comparisons with independent ionosphere measurements such as Very Long Baseline Interferometry, integrated dual-frequency Doppler, and theTOPEX dual- frequency.

Ionospheric models provide the only recourse short of adding a second frequency to the altimeter. Unfortunately, measurements of the ionosphere are lacking over the oceans or ice sheets where they are most needed.

to extend ionospheric measurements by simply adding a GPS receiver and downward-pointing antenna to satellites carrying single. Ionospheric Systems Development Group atJP1, has been studying the ionospberc using GPS for six years and is a co-developer ofthe GPS-based global ionospheric mapping (GIM) tcchniquc.

His current work is focused on improving and validatingGIM, global ionospheric calibration of single-frequency ocean altimetry missions.

Get this from a library. Ionospheric calibration for single frequency altimeter measurements. [William S Schreiner; George H Born; United States. National Aeronautics and Space Administration.]. We examine the feasibility of using satellite altimeter data to measure the long‐term change of global sea level (estimated from tide gauge data to be a rise of approximately cm yr −1).

Two and one‐half years of collinear Geosat altimeter data (–) are used together with a 17‐day set of Seasat altimetry (July–August Scientific books for more information; Education.

Argonautica educational project; Boardgame; Books & magazines; Altimetry courses; Useful information. Shortcut to Licence and registration; Shortcut to Aviso+ user handbooks; Shortcut to Tools; Shortcut to Validation reports; Shortcut to Mono and multi-mission processing; Shortcut to FAQ.

Because this effect is dispersive, measurement of the range at two frequencies allows it to be estimated. Under typical ocean conditions of 2-metre significant wave height, the Ku band ionospheric range correction that is determined from the dual frequency measurements from the altimeter is expected to have an accuracy of ± cm.

References. Hence, various ionospheric models are employed to eliminate ionospheric delay for single‐frequency users, which can be classified into three kinds. The first is physical models, which is solved by a set of energy and momentum equations for the plasma, including the Time Dependent Ionospheric Model (TDIM) (Schunk et al., ) and Coupled.

Komjathy A, Langley RB, Bilitza D () Ingesting GPS-derived TEC data into the international reference ionosphere for single frequency radar altimeter ionospheric delay correction. Adv Space Res 22(6)– Google Scholar. The multi-frequency receivers used in the GNSS stations are, however, much more expensive than single frequency receivers which are widely distributed as consumer products.

In the present study, an estimation method of ionospheric TEC map from single frequency measurements of. The Ku-band and C-band bandwidth is MHz, with C-band selectable at MHz; the antenna control pointing accuracy is º (1 σ).NRA mass = kg, power = W, altitude measurement accuracy of cm.

Simultaneous measurements at both frequencies so that ionospheric range delay can be directly estimated from the two measurements. The TOPEX dual-frequency altimeter ( GHz, GHz) provides independant global TEC90 measurements with an residual accuracy less than 3 TECU [Yuan et al., ]. Although the orbital parameters of ERS-2 and TOPEX are different (a= resp.

km, i= resp. 66 degrees), it is possible to compare TEC90 data from both missions if the. This study is a preliminary analysis of the accuracy of various ionosphere models to correct single frequency altimeter height measurements for ionospheric path delay. In particular, research focused on adjusting empirical and parameterized ionosphere models in the parameterized real-time ionospheric specification model (PRISM) using total.

measurements that are outside the calibration range will need to be qualified. This SOP requires that the manufacturer’s instruction manual (including the instrument specifications) accompany the instrument into the field.

FREQUENCY OF CALIBRATION. At a minimum, the instrument is calibrated prior to use on the day the measurements are to be. Scale factor mitigating non-compliance of double-frequency altimeter measurements of the ionospheric electron content over the oceans with GPS-TEC maps.

Springer Gulyaeva, T., Arikan, F., Hernandez-Pajares, M., Veselovsky, I. Fitting ocean models to altimeter sea surface height (SSH) measurements requires knowledge of instrument noise (radar noise, sea state bias, path delay corrections, and orbit errors) and “representation” errors related to SSH signals (e.g., tidal or pressure driven) not computed in the models.

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda). We compare TEC measurements from the NASA Radar Altimeter and DORIS instrument on board TOPEX/POSEIDON with GPS TEC estimates, and evaluate different GPS data analysis strategies.

We verify that global tomographic GPS analysis using a voxel grid is well suited for ionospheric calibration of altimeters. In the absence of other external requirements for specific intervals, NIST recommends that calibration and measurement laboratories adopt internal measurement assurance programs that include cross-comparisons of primary and secondary measurement standards.

Recording and analyzing the resulting data in control charts can be used to characterize. We compare TEC measurements from the NASA Radar Altimeter and DORIS instrument on board TOPEX/POSEIDON with GPS TEC estimates, and evaluate different GPS data analysis strategies.

We verify that global tomographic GPS analysis using a voxel grid is well suited for ionospheric calibration of altimeters. We show that a 1‐day fit of 20‐second‐averaged NRA ionospheric correction data. Iijima B. A., Harris I. L., Ho C. M., et al.

Automated daily process for global ionospheric total electron content maps and satellite ocean altimeter ionospheric calibration based on Global Positioning System data. Journal of Atmospheric and Solar-Terrestrial Physics. ; 61 (16)– doi: /S(99)X. frequency measurements (GPS L 1 and L 2).

The following relation for group delay due to propagation through plasma applies when the radio frequency vastly exceeds the plasma frequency (peak ionospheric plasma frequencies are below 10 MHz), TEC f ∆r = • 2(1) where the group delay, ∆r, is measured in meters.instrumental inter-frequency bias estimation capability.

Ionospheric total electroncontcn(is extracted from Gl>S by computing the differencebctwccn satellite-reccivcr measured at the twoGI’S frcquencics, and (see Paper I).T}lc line-of-sight measurements of ionospheric delay arcintcrpo]atcd to form a wide-area.The standalone GPS-based FIS has a single frequency GPS receiver, a radar altimeter and a TVPS (TeleVision Positioning System).

The same kinds of radar altimeter and TVPS being used in the current Inertial-based AFIS are taken in the standalone GPS-based FIS.

The 95% accuracy of the radar altimeter is better than 15cm [4].