dc.contributor |
Universitat Politècnica de Catalunya. Departament de Física Aplicada |
dc.contributor |
Universitat Politècnica de Catalunya. Departament de Matemàtica Aplicada IV |
dc.contributor |
Universitat Politècnica de Catalunya. gAGE - Grup d'Astronomia i Geomàtica |
dc.contributor.author |
Jofre, Martí |
dc.contributor.author |
Ramos Bosch, Pedro |
dc.contributor.author |
Feng, S. |
dc.contributor.author |
Ochieng, W. |
dc.contributor.author |
Samson, J |
dc.contributor.author |
Tossaint, M |
dc.contributor.author |
Hernández Pajares, Manuel |
dc.contributor.author |
Juan Zornoza, José Miguel |
dc.contributor.author |
Sanz Subirana, Jaume |
dc.contributor.author |
Aragón Ángel, María Ángeles |
dc.date |
2012-01 |
dc.identifier.citation |
Feng, S. [et al.]. Integrity monitoring for carrier phase ambiguities. "Journal of navigation", Gener 2012, vol. 65, núm. 1, p. 41-58. |
dc.identifier.citation |
0373-4633 |
dc.identifier.citation |
10.1017/S037346331100052X |
dc.identifier.uri |
http://hdl.handle.net/2117/14276 |
dc.language.iso |
eng |
dc.relation |
http://www.rairo-ita.org/action/displayFulltext?type=1&fid=8440674&jid=NAV&volumeId=65&issueId=01&aid=8440672&bodyId=&membershipNumber=&societyETOCSession= |
dc.rights |
Attribution-NonCommercial-NoDerivs 3.0 Spain |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.rights |
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
dc.subject |
Àrees temàtiques de la UPC::Enginyeria de la telecomunicació::Radiocomunicació i exploració electromagnètica::Satèl·lits i ràdioenllaços |
dc.subject |
Àrees temàtiques de la UPC::Matemàtiques i estadística::Geometria::Geometria computacional |
dc.subject |
Geometry, Algebraic |
dc.subject |
Satèl·lits artificials |
dc.subject |
Geometria computacional |
dc.subject |
14Q Computational aspects in algebraic geometry |
dc.title |
Integrity monitoring for carrier phase ambiguities |
dc.type |
info:eu-repo/semantics/publishedVersion |
dc.type |
info:eu-repo/semantics/article |
dc.description.abstract |
The determination of the correct integer number of carrier cycles (integer ambiguity) is
the key to high accuracy positioning with carrier phase measurements from Global
Navigation Satellite Systems (GNSS). There are a number of current methods for resolving
ambiguities including the Least-squares AMBiguity Decorrelation Adjustment (LAMBDA)
method, which is a combination of least-squares and a transformation to reduce the search
space. The current techniques to determine the level of confidence (integrity) of the resolved
ambiguities (i.e. ambiguity validation), usually involve the construction of test statistics,
characterisation of their distribution and definition of thresholds. Example tests applied
include ratio, F-distribution, t-distribution and Chi-square distribution. However, the
assumptions that underpin these tests have weaknesses. These include the application of a
fixed threshold for all scenarios, and therefore, not always able to provide an acceptable
integrity level in the computed ambiguities. A relatively recent technique referred to as Integer
Aperture (IA) based on the ratio test with a large number of simulated samples of float
ambiguities requires significant computational resources. This precludes the application of IA
in real time.
This paper proposes and demonstrates the power of an integrity monitoring technique that
is applied at the ambiguity resolution and positioning stages. The technique has the important
benefit of facilitating early detection of any potential threat to the position solution, originating
in the ambiguity space, while at the same time giving overall protection in the position
domain based on the required navigation performance. The proposed method uses the
conventional test statistic for ratio testing together with a doubly non-central F distribution to
compute the level of confidence (integrity) of the ambiguities. Specifically, this is determined
as a function of geometry and the ambiguity residuals from least squares based ambiguity
resolution algorithms including LAMBDA. A numerical method is implemented to compute
the level of confidence in real time.
The results for Precise Point Positioning (PPP) with simulated and real data demonstrate
the power and efficiency of the proposed method in monitoring both the integrity
of the ambiguity computation and position solution processes. Furthermore, due to the fact that the method only requires information from least squares based ambiguity resolution
algorithms, it is easily transferable to conventional Real Time Kinematic (RTK)
positioning. |
dc.description.abstract |
Peer Reviewed |