Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236938
G. Stienne, S. Reboul, J. Choquel, M. Benjelloun
This paper proposes circular data processing tools dedicated to the tracking of the phase of GNSS signals in a Phase Open Loop, particularly in case of multi-channel signal structure. The objective of processing the phase in an open loop is to avoid time-correlation between two successive measurements. This allows the use of loop filters in order to smooth the measurements without producing unwanted oscillations in the phase estimations. In order to process the angular values produced by the Phase Open Loop, the choice had been made to develop a filter and a fusion operator in a Bayesian framework with circular statistics distributions. The proposed tools are assessed on synthetic and real data.
{"title":"Circular data processing tools applied to a Phase Open Loop architecture for multi-channels signals tracking","authors":"G. Stienne, S. Reboul, J. Choquel, M. Benjelloun","doi":"10.1109/PLANS.2012.6236938","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236938","url":null,"abstract":"This paper proposes circular data processing tools dedicated to the tracking of the phase of GNSS signals in a Phase Open Loop, particularly in case of multi-channel signal structure. The objective of processing the phase in an open loop is to avoid time-correlation between two successive measurements. This allows the use of loop filters in order to smooth the measurements without producing unwanted oscillations in the phase estimations. In order to process the angular values produced by the Phase Open Loop, the choice had been made to develop a filter and a fusion operator in a Bayesian framework with circular statistics distributions. The proposed tools are assessed on synthetic and real data.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132277568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236833
A. Garcia‐Pena, O. Julien, C. Macabiau, A. Emmanuele, M. Luise, J. Won, D. Fontanella, M. Paonni, B. Eissfeller, F. Zanier, G. López-Risueño
Non classical signals, signals not made of rectangular shaped pulses, are being analyzed as possible candidates for the next generation of GNSS signals. One such a signal is the filtered multi-tone (FMT) which is a multi-carrier signal (MC) having a MC-DS-CDMA structure: each subcarrier transports a classical GNSS signal but without using rectangular shaped pulses. Some studies have been conducted on the FMT signal performances such as the out-of-band (OOB) emission and multipath resistance. However, due to its MC nature, the distribution of the transmitted data onto the different subcarriers becomes a relevant factor to take into account on the final signal design. In this paper, different data distributions are proposed in order to enhance different signal performance and the receiver structure associated to each data distribution is also analyzed.
{"title":"FMT signal options and associated receiver architectures for GNSS","authors":"A. Garcia‐Pena, O. Julien, C. Macabiau, A. Emmanuele, M. Luise, J. Won, D. Fontanella, M. Paonni, B. Eissfeller, F. Zanier, G. López-Risueño","doi":"10.1109/PLANS.2012.6236833","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236833","url":null,"abstract":"Non classical signals, signals not made of rectangular shaped pulses, are being analyzed as possible candidates for the next generation of GNSS signals. One such a signal is the filtered multi-tone (FMT) which is a multi-carrier signal (MC) having a MC-DS-CDMA structure: each subcarrier transports a classical GNSS signal but without using rectangular shaped pulses. Some studies have been conducted on the FMT signal performances such as the out-of-band (OOB) emission and multipath resistance. However, due to its MC nature, the distribution of the transmitted data onto the different subcarriers becomes a relevant factor to take into account on the final signal design. In this paper, different data distributions are proposed in order to enhance different signal performance and the receiver structure associated to each data distribution is also analyzed.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115513023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236984
Cheng Chen, W. Chai, Ahmad Kamal Nasir, H. Roth
It is an important and fundamental ability for a mobile robot to know its position and attitude. This article introduces several approaches for solving an indoor mobile robot positioning problem based on recursive estimation algorithm. Sensor information from a low cost inertial measurement unit, wheel mounted encoders and Wi-Fi is fused to get current robot position. Since one cannot ignore the nature properties of robot dynamic constraints, the method purposed in this paper involves incorporation of those constraints. The final results are based on field experiment.
{"title":"Low cost IMU based indoor mobile robot navigation with the assist of odometry and Wi-Fi using dynamic constraints","authors":"Cheng Chen, W. Chai, Ahmad Kamal Nasir, H. Roth","doi":"10.1109/PLANS.2012.6236984","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236984","url":null,"abstract":"It is an important and fundamental ability for a mobile robot to know its position and attitude. This article introduces several approaches for solving an indoor mobile robot positioning problem based on recursive estimation algorithm. Sensor information from a low cost inertial measurement unit, wheel mounted encoders and Wi-Fi is fused to get current robot position. Since one cannot ignore the nature properties of robot dynamic constraints, the method purposed in this paper involves incorporation of those constraints. The final results are based on field experiment.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116232713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236924
D. Zachariah, M. Jansson
We present a navigation system based on a monocular camera and an inertial measurement unit. The system detects visual tags and fuses the measurements on the image plane with inertial signals to perform pose estimation and localization using a Sigma-Point Kalman filter. The tags are detected by edge-based feature extraction and channel codes. During periods in which tags are not visible, epipolar constraints, arising from past views, are exploited to significantly reduce the position error growth rate. The experimental results in an office building indicate capabilities for indoor navigation.
{"title":"Fusing visual tags and inertial information for indoor navigation","authors":"D. Zachariah, M. Jansson","doi":"10.1109/PLANS.2012.6236924","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236924","url":null,"abstract":"We present a navigation system based on a monocular camera and an inertial measurement unit. The system detects visual tags and fuses the measurements on the image plane with inertial signals to perform pose estimation and localization using a Sigma-Point Kalman filter. The tags are detected by edge-based feature extraction and channel codes. During periods in which tags are not visible, epipolar constraints, arising from past views, are exploited to significantly reduce the position error growth rate. The experimental results in an office building indicate capabilities for indoor navigation.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123282303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236954
V. Indelman, P. Gurfil, E. Rivlin, H. Rotstein
One of the hard issues that arises in distributed navigation is keeping an up-to-date and consistent estimation of the dependency between the solutions computed by each one of the involved agents. This issue is critical for the consistent information fusion in distributed cooperative navigation and was recently tackled using a graph-based approach for the on-demand calculation of cross-covariance terms. In particular, the approach was applied to a method for visual aided, distributed cooperative navigation based on three-view geometry constraints, in which a measurement is formulated whenever the same scene is observed by several robots, not necessarily at the same time. The purpose of this paper is twofold. First, the claim that on-demand calculation of cross-covariance terms in three-view-based cooperative navigation is further substantiated, and the difficulties with other existing techniques are emphasized. Second, the efficiency of using the on-demand calculations is validated by comparing the results to those obtained by assuming the three-view multi-robot measurements schedule is known a priori. In this latter method, the required cross-covariance terms are calculated using a fixed-lag centralized smoother. The comparison clearly shows the advantages of using the on-demand scheme.
{"title":"Graph-based cooperative navigation using three-view constraints: Method validation","authors":"V. Indelman, P. Gurfil, E. Rivlin, H. Rotstein","doi":"10.1109/PLANS.2012.6236954","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236954","url":null,"abstract":"One of the hard issues that arises in distributed navigation is keeping an up-to-date and consistent estimation of the dependency between the solutions computed by each one of the involved agents. This issue is critical for the consistent information fusion in distributed cooperative navigation and was recently tackled using a graph-based approach for the on-demand calculation of cross-covariance terms. In particular, the approach was applied to a method for visual aided, distributed cooperative navigation based on three-view geometry constraints, in which a measurement is formulated whenever the same scene is observed by several robots, not necessarily at the same time. The purpose of this paper is twofold. First, the claim that on-demand calculation of cross-covariance terms in three-view-based cooperative navigation is further substantiated, and the difficulties with other existing techniques are emphasized. Second, the efficiency of using the on-demand calculations is validated by comparing the results to those obtained by assuming the three-view multi-robot measurements schedule is known a priori. In this latter method, the required cross-covariance terms are calculated using a fixed-lag centralized smoother. The comparison clearly shows the advantages of using the on-demand scheme.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"206 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122804596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236936
L. Fairfax, F. Fresconi
A state estimation method for gun-launched precision projectiles using affordable technologies is presented. Navigation algorithms were developed to incorporate flight dynamic models with measurements from inertial sensors and, if available, GPS. GPS is used to estimate an inertial sensor bias which can then be used if GPS is lost later in flight. This novel technique allows GPS to continue to benefit the flight after it is unavailable and allows noisy, low cost sensors to provide a useful state estimate. Simulations were conducted to assess algorithm performance over a range of conditions. These results indicated that the algorithm with only 10 seconds of GPS availability yields a position error of less than 35 m over a 30 s flight. This effort shows that navigation error using coupled GPS/INS is sufficient to increase system accuracy for munitions even if GPS should become unavailable during flight.
{"title":"Loosely-coupled GPS/INS state estimation in precision projectiles","authors":"L. Fairfax, F. Fresconi","doi":"10.1109/PLANS.2012.6236936","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236936","url":null,"abstract":"A state estimation method for gun-launched precision projectiles using affordable technologies is presented. Navigation algorithms were developed to incorporate flight dynamic models with measurements from inertial sensors and, if available, GPS. GPS is used to estimate an inertial sensor bias which can then be used if GPS is lost later in flight. This novel technique allows GPS to continue to benefit the flight after it is unavailable and allows noisy, low cost sensors to provide a useful state estimate. Simulations were conducted to assess algorithm performance over a range of conditions. These results indicated that the algorithm with only 10 seconds of GPS availability yields a position error of less than 35 m over a 30 s flight. This effort shows that navigation error using coupled GPS/INS is sufficient to increase system accuracy for munitions even if GPS should become unavailable during flight.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124978672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236935
Chang Liu, Jie Li, Kewei Huang, Fei Liu
This work presents a new method for estimating the initial orientation of one micro air vehicle (MAV) whose navigation system is powered in a dynamic condition, using low cost three-axis magnetometer and three-axis accelerometer. Although the earth's magnetic field offers a steady reference vector to determine the attitude, only one vector is insufficient to get accurate values. To solve this problem, the variation of the MAV's acceleration is added to the reference vector. And our focus is on how to combine the direction of magnetic field and acceleration into an entirety effectively, and use this method in a special dynamic state, parachuting. The challenge is that the whole estimation process must be accomplished in dynamic state and there is no external calibration information. Thus, advanced Gauss-Newton is adopted to improve the efficiency, and a model of parachuting is built to describe the variation of acceleration. The results of simple simulation on computer and experiment show that the method has a good performance in a simple surrounding.
{"title":"A quaternion-based initial orientation estimation system suitable for one special dynamic state Using low cost magnetometer and accelerometer","authors":"Chang Liu, Jie Li, Kewei Huang, Fei Liu","doi":"10.1109/PLANS.2012.6236935","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236935","url":null,"abstract":"This work presents a new method for estimating the initial orientation of one micro air vehicle (MAV) whose navigation system is powered in a dynamic condition, using low cost three-axis magnetometer and three-axis accelerometer. Although the earth's magnetic field offers a steady reference vector to determine the attitude, only one vector is insufficient to get accurate values. To solve this problem, the variation of the MAV's acceleration is added to the reference vector. And our focus is on how to combine the direction of magnetic field and acceleration into an entirety effectively, and use this method in a special dynamic state, parachuting. The challenge is that the whole estimation process must be accomplished in dynamic state and there is no external calibration information. Thus, advanced Gauss-Newton is adopted to improve the efficiency, and a model of parachuting is built to describe the variation of acceleration. The results of simple simulation on computer and experiment show that the method has a good performance in a simple surrounding.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128708264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236864
A. Rugamer, S. Urquijo, M. Eppel, H. Milosiu, J. Gorner, G. Rohmer
This paper presents the overall architecture, first test structure implementations, and measurement results of an integrated GNSS front-end based on intentional path overlay. The front-end ASIC supports simultaneous multiband, multi-system GNSS reception of GPS L5 / Galileo E5 / GLONASS G3 and GPS L1 / Galileo E1 / GLONASS G1 signals with up to 52MHz bandwidth while using only one common baseband path thanks to an intentional analog signal overlay. Test structures of the RF and baseband parts were realized in a 1.8 V, 150nm RF-CMOS technology packaged in a QFN48 housings with full ESD protection. Both chips are described in detail regarding their design and their actual measurement results.
{"title":"An integrated overlay architecture based multi-GNSS front-end","authors":"A. Rugamer, S. Urquijo, M. Eppel, H. Milosiu, J. Gorner, G. Rohmer","doi":"10.1109/PLANS.2012.6236864","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236864","url":null,"abstract":"This paper presents the overall architecture, first test structure implementations, and measurement results of an integrated GNSS front-end based on intentional path overlay. The front-end ASIC supports simultaneous multiband, multi-system GNSS reception of GPS L5 / Galileo E5 / GLONASS G3 and GPS L1 / Galileo E1 / GLONASS G1 signals with up to 52MHz bandwidth while using only one common baseband path thanks to an intentional analog signal overlay. Test structures of the RF and baseband parts were realized in a 1.8 V, 150nm RF-CMOS technology packaged in a QFN48 housings with full ESD protection. Both chips are described in detail regarding their design and their actual measurement results.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128830108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236968
L. Lestarquit, O. Nouvel
This paper will review the necessary conditions for having a code tracking bias due to cross-correlation (XC), focussing on the current C/A code, and show that it will be indeed very unlikely for signals coming from GPS satellites, but it can happen for signals coming from satellites having a low dynamic, such as SBAS or IGSO satellites. Measurement campaigns on SBAS have been made and a surprising result has been found: even though the measured error envelope complies with the theory, the nature of the error is noisy whereas it should have been a bias. The reason for this was explained: this is due to carrier phase jitter on the SBAS ranging signal. The physics of the cross-correltion error will be reviewed. It has many analogies with the multipath effect. The condition for XC errors to happen will be detailed. They are : Doppler collision, data message similitude, and presence of a XC peak. The situation in which XC tracking error happen will be detailed. There are almost impossible for GPS signal due to the satellite high Doppler, but more likely for SBAS satellites with low motion. For WAAS, the message frames of the 2 satellites are most of the time correlated with a correlation index between 0.8 and 1, for EGNOS the messages are sometimes correlated, but most of the timre not, depending on whether the same message type are broadcast at the same time by the satellites. The message symbol have to be received at the same time for the XC error to be maximum. If there is a one symbol shift, that is a 2 ms or a 600km relative code delay, then the received symbols becomes uncorrelated. This explains that XC error can happen only on a very narrow strip, a few hundred km wide only. Additionnaly, within this strip the user must be positioned in a place corresponding to a XC function peak when the Doppler collision happens. A test campaign was made inside this strip. The observed error envelope was found to match the predicted error, but it was noticed an important carrier phase jitter that reached several carrier cycles. This caused the XC error bias to be changed into a random error. This allow to filter out the XC error with carrier smoothing. There is a paradoxal situation : if the carrier phase jitter anomaly was improved, the XC error would become a bias that couln't be filtered with carrier smoothing. If SBAS signal shall be used for ranging, XC error could be taken into account at the receiver level. There are many possibilities, one could be to ignore code measurement in case of Doppler collision, another could be to correct it with an error model.
{"title":"Determining and measuring the true impact of C/A code cross-correlation on tracking—Application to SBAS georanging","authors":"L. Lestarquit, O. Nouvel","doi":"10.1109/PLANS.2012.6236968","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236968","url":null,"abstract":"This paper will review the necessary conditions for having a code tracking bias due to cross-correlation (XC), focussing on the current C/A code, and show that it will be indeed very unlikely for signals coming from GPS satellites, but it can happen for signals coming from satellites having a low dynamic, such as SBAS or IGSO satellites. Measurement campaigns on SBAS have been made and a surprising result has been found: even though the measured error envelope complies with the theory, the nature of the error is noisy whereas it should have been a bias. The reason for this was explained: this is due to carrier phase jitter on the SBAS ranging signal. The physics of the cross-correltion error will be reviewed. It has many analogies with the multipath effect. The condition for XC errors to happen will be detailed. They are : Doppler collision, data message similitude, and presence of a XC peak. The situation in which XC tracking error happen will be detailed. There are almost impossible for GPS signal due to the satellite high Doppler, but more likely for SBAS satellites with low motion. For WAAS, the message frames of the 2 satellites are most of the time correlated with a correlation index between 0.8 and 1, for EGNOS the messages are sometimes correlated, but most of the timre not, depending on whether the same message type are broadcast at the same time by the satellites. The message symbol have to be received at the same time for the XC error to be maximum. If there is a one symbol shift, that is a 2 ms or a 600km relative code delay, then the received symbols becomes uncorrelated. This explains that XC error can happen only on a very narrow strip, a few hundred km wide only. Additionnaly, within this strip the user must be positioned in a place corresponding to a XC function peak when the Doppler collision happens. A test campaign was made inside this strip. The observed error envelope was found to match the predicted error, but it was noticed an important carrier phase jitter that reached several carrier cycles. This caused the XC error bias to be changed into a random error. This allow to filter out the XC error with carrier smoothing. There is a paradoxal situation : if the carrier phase jitter anomaly was improved, the XC error would become a bias that couln't be filtered with carrier smoothing. If SBAS signal shall be used for ranging, XC error could be taken into account at the receiver level. There are many possibilities, one could be to ignore code measurement in case of Doppler collision, another could be to correct it with an error model.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127501853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-04-23DOI: 10.1109/PLANS.2012.6236972
C. Hargreaves, P. Williams, M. Bransby
eLoran has the potential to act as a cross-platform backup radio-navigation system to GPS to provide Position Navigation and Timing. As service providers of differential-eLoran for maritime navigation, the General Lighthouse Authorities of the UK and Ireland (the GLAs) must ensure that the system meets the internationally agreed standards for Accuracy, Availability, Continuity and Integrity. For eLoran to provide accuracy better than 10m (95%), the user must have knowledge of the signal propagation Additional Secondary Factors (ASFs). The GLAs are charged with the measurement, validation and publication of accurate ASF tables for use within users' receivers. To this end an extensive surveying campaign is required in order to measure the ASF tables for the nominated harbours and port approaches for eLoran IOC before 2014. It is important that sufficient survey data is gathered to ensure high-quality ASF tables can be produced, but equally that surveying effort and ship-time are kept to a minimum to reduce costs. Making use of an ASF error-budget, novel processing techniques and an Integrity-based Quality Assurance methodology for ASF surveying have been created. This is designed to give the GLAs a real-time picture of the progress of an on-going survey, so surveying resources can be used effectively to maximise data quality. As an additional benefit, ASF -table Quality figures can be fed into an eLoran Integrity equation to keep the mariner informed of the level of performance they can expect from the eLoran system. This will ensure that eLoran is used with an appropriate degree of trust during the various phases of a voyage for which it is used.
{"title":"ASF quality assurance for eLoran","authors":"C. Hargreaves, P. Williams, M. Bransby","doi":"10.1109/PLANS.2012.6236972","DOIUrl":"https://doi.org/10.1109/PLANS.2012.6236972","url":null,"abstract":"eLoran has the potential to act as a cross-platform backup radio-navigation system to GPS to provide Position Navigation and Timing. As service providers of differential-eLoran for maritime navigation, the General Lighthouse Authorities of the UK and Ireland (the GLAs) must ensure that the system meets the internationally agreed standards for Accuracy, Availability, Continuity and Integrity. For eLoran to provide accuracy better than 10m (95%), the user must have knowledge of the signal propagation Additional Secondary Factors (ASFs). The GLAs are charged with the measurement, validation and publication of accurate ASF tables for use within users' receivers. To this end an extensive surveying campaign is required in order to measure the ASF tables for the nominated harbours and port approaches for eLoran IOC before 2014. It is important that sufficient survey data is gathered to ensure high-quality ASF tables can be produced, but equally that surveying effort and ship-time are kept to a minimum to reduce costs. Making use of an ASF error-budget, novel processing techniques and an Integrity-based Quality Assurance methodology for ASF surveying have been created. This is designed to give the GLAs a real-time picture of the progress of an on-going survey, so surveying resources can be used effectively to maximise data quality. As an additional benefit, ASF -table Quality figures can be fed into an eLoran Integrity equation to keep the mariner informed of the level of performance they can expect from the eLoran system. This will ensure that eLoran is used with an appropriate degree of trust during the various phases of a voyage for which it is used.","PeriodicalId":282304,"journal":{"name":"Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium","volume":"248 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114551153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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