Pub Date : 2010-05-04DOI: 10.1109/PLANS.2010.5507322
A. Soloviev, D. Venable
This paper investigates into the feasibility of a combined use of Global Positioning System (GPS) and vision-based measurements for navigation in challenged GPS environments such as urban canyons and indoors. In these environments, a GPS-only navigation solution fix is generally not feasible. However, limited GPS measurements (for example, for two or three satellites) may still be available. These limited measurements can be exploited to enhance the efficacy of alternative navigation aids such as vision-aided inertial. This paper presents a method for the combination of limited GPS carrier phase measurements with features that are extracted from images of a monocular video camera. An integrated GPS/vision solution estimates position changes and orientation of the camera's body-frame; and, initializes ranges to vision-based features. Simulation results and initial experimental results are presented to validate the proposed integration method and demonstrate its performance.
{"title":"Integration of GPS and vision measurements for navigation in GPS challenged environments","authors":"A. Soloviev, D. Venable","doi":"10.1109/PLANS.2010.5507322","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507322","url":null,"abstract":"This paper investigates into the feasibility of a combined use of Global Positioning System (GPS) and vision-based measurements for navigation in challenged GPS environments such as urban canyons and indoors. In these environments, a GPS-only navigation solution fix is generally not feasible. However, limited GPS measurements (for example, for two or three satellites) may still be available. These limited measurements can be exploited to enhance the efficacy of alternative navigation aids such as vision-aided inertial. This paper presents a method for the combination of limited GPS carrier phase measurements with features that are extracted from images of a monocular video camera. An integrated GPS/vision solution estimates position changes and orientation of the camera's body-frame; and, initializes ranges to vision-based features. Simulation results and initial experimental results are presented to validate the proposed integration method and demonstrate its performance.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91287877","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507128
M. De Agostino, A. Manzino, M. Piras
MEMS inertial sensors are widely used for navigation applications where size, weight, power and cost are key sides, such as autonomous vehicular control and pedestrian navigation. Otherwise, if there is no doubt that MEMS technologies represents an interesting turning point for low cost inertial-based sensors and applications, nevertheless it is absolutely true that, in order to obtain good positioning accuracies, it is necessary to investigate very well the behaviour of these MEMS sensors and realize special test calibrations, both in static and kinematic conditions. In order to evaluate the potentialities (and the limits) of these sensors, comparative tests have been realized considering MEMS inertial sensors with different characteristics and different performances, First of all, a static calibration of the sensors has been made, in order to compare the bias values and their stability with respect to the time. In particular, an Allan-variance analysis and a modified six position static test were carried out for each sensor, preserving carefully the same environment conditions for all the tests. After the lab tests, the performances of all the sensors were compared in a field kinematic test, integrating their data with a GPS solution.
{"title":"Performances comparison of different MEMS-based IMUs","authors":"M. De Agostino, A. Manzino, M. Piras","doi":"10.1109/PLANS.2010.5507128","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507128","url":null,"abstract":"MEMS inertial sensors are widely used for navigation applications where size, weight, power and cost are key sides, such as autonomous vehicular control and pedestrian navigation. Otherwise, if there is no doubt that MEMS technologies represents an interesting turning point for low cost inertial-based sensors and applications, nevertheless it is absolutely true that, in order to obtain good positioning accuracies, it is necessary to investigate very well the behaviour of these MEMS sensors and realize special test calibrations, both in static and kinematic conditions. In order to evaluate the potentialities (and the limits) of these sensors, comparative tests have been realized considering MEMS inertial sensors with different characteristics and different performances, First of all, a static calibration of the sensors has been made, in order to compare the bias values and their stability with respect to the time. In particular, an Allan-variance analysis and a modified six position static test were carried out for each sensor, preserving carefully the same environment conditions for all the tests. After the lab tests, the performances of all the sensors were compared in a field kinematic test, integrating their data with a GPS solution.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90293159","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507228
M. Joerger, J. Neale, B. Pervan, S. Datta‐Barua
The integration of ranging signals from multiple satellite constellations opens the possibility for rapid, robust and accurate positioning over wide areas. Algorithms for the simultaneous estimation of carrier phase cycle ambiguities and user position and for the detection of faults over a fixed smoothing time-interval were derived in previous work. For high-integrity precision applications, ensuring the robustness of measurement error and fault-models is an exacting task, especially when considering sequences of observations. In this research, a new RAIM-based approach is established, which aims at directly determining the worst-case single-satellite fault profile. Also, the robustness of newly derived ionospheric error models is experimentally evaluated using dual-frequency GPS data collected over several months at multiple locations. An integrity analysis is devised to quantify the impact of traveling ionospheric disturbances (TIDs) on the final user position solution. Finally, overall navigation system performance is assessed for various combinations of GPS, Galileo and low earth orbiting Iridium satellite signals.
{"title":"Measurement error models and fault-detection algorithms for multi-constellation navigation systems","authors":"M. Joerger, J. Neale, B. Pervan, S. Datta‐Barua","doi":"10.1109/PLANS.2010.5507228","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507228","url":null,"abstract":"The integration of ranging signals from multiple satellite constellations opens the possibility for rapid, robust and accurate positioning over wide areas. Algorithms for the simultaneous estimation of carrier phase cycle ambiguities and user position and for the detection of faults over a fixed smoothing time-interval were derived in previous work. For high-integrity precision applications, ensuring the robustness of measurement error and fault-models is an exacting task, especially when considering sequences of observations. In this research, a new RAIM-based approach is established, which aims at directly determining the worst-case single-satellite fault profile. Also, the robustness of newly derived ionospheric error models is experimentally evaluated using dual-frequency GPS data collected over several months at multiple locations. An integrity analysis is devised to quantify the impact of traveling ionospheric disturbances (TIDs) on the final user position solution. Finally, overall navigation system performance is assessed for various combinations of GPS, Galileo and low earth orbiting Iridium satellite signals.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81373722","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507340
Fang-Cheng Chan, M. Joerger, B. Pervan
In this paper, a validated stochastic clock random error model is used to derive a correct time correlation matrix for a sequence of clock random errors. A batch estimator incorporating the complete time correlation matrix is developed to account for clock random errors. Performance improvement for the proposed receiver clock-aided navigation system is fully investigated. A benchmark application of an aircraft precision approach is used to evaluate the system availability performance with a single satellite failure assumption.
{"title":"High integrity stochastic modeling of GPS receiver clock for improved positioning and fault detection performance","authors":"Fang-Cheng Chan, M. Joerger, B. Pervan","doi":"10.1109/PLANS.2010.5507340","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507340","url":null,"abstract":"In this paper, a validated stochastic clock random error model is used to derive a correct time correlation matrix for a sequence of clock random errors. A batch estimator incorporating the complete time correlation matrix is developed to account for clock random errors. Performance improvement for the proposed receiver clock-aided navigation system is fully investigated. A benchmark application of an aircraft precision approach is used to evaluate the system availability performance with a single satellite failure assumption.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84981264","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507309
Major J. Beich, Col M. Veth
Autonomous navigation in areas where Global Positioning System (GPS) solutions are unavailable continues to be a significant challenge. One example application is the relative targeting and navigation problem for next-generation autonomous vehicles. In this application, refined navigation state information (position, velocity, and attitude) can be determined with the addition of a high-resolution camera to an Inertial Navigation System (INS)-aided navigation system. In the proposed employment scenario, GPS information is not available, the location and structure of a reference landmark is known to a high degree of precision, and the initial navigation states (along with their respective uncertainties) of the vehicle are known to a variable degree of uncertainty. The landmark environment is modeled in advance using commercially available Computer Aided Design (CAD) software and photographs of objects within the scene. This information is intended to be combined with INS data in a statistically-rigorous predictive rendering algorithm to determine error states for implementation in an Unscented Kalman Filter (UKF). The error states are then used to correct the navigation solution. Several methods of exploiting the available information are compared to determine “best performers” in terms of speed, precision, and situational appropriateness. For this research, all methods are based on a proposed Statistical Predictive Rendering (SPR) technique which consists of constructing synthetic views of the scene from the perspective of the vehicle for comparison with actual images from the on-board camera. This predictively-rendered image is then compared to measured images using either feature-based or pixel-based comparison methods which serve to improve the accuracy of the correspondence search technique employed. Vision-aided navigation solutions are an active area of research that incorporates knowledge from the estimation, image processing, and navigation fields of engineering. Past efforts have focused on stochastically constraining feature point correspondence in successive images of the ground from the perspective of an overflying air vehicle using an Extended Kalman Filter (EKF) or UKF, and SPR in the problem of autonomous aerial refueling using an EKF. The proposed algorithm elements are tested using a combination of experimental and simulated data. Currently, the simulated flight profiles show that the navigation solution accuracy and robustness is improved by including SPR-based visual information into the tightly coupled framework. Further experimental tests will be conducted in our laboratory using realistic scenes and in-flight as part of a Test Pilot School project. Conclusions regarding the performance of the tightly-coupled SPR technique will be presented.
{"title":"Tightly-coupled image-aided inertial relative navigation using Statistical Predictive Rendering (SPR) techniques and a priori world Models","authors":"Major J. Beich, Col M. Veth","doi":"10.1109/PLANS.2010.5507309","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507309","url":null,"abstract":"Autonomous navigation in areas where Global Positioning System (GPS) solutions are unavailable continues to be a significant challenge. One example application is the relative targeting and navigation problem for next-generation autonomous vehicles. In this application, refined navigation state information (position, velocity, and attitude) can be determined with the addition of a high-resolution camera to an Inertial Navigation System (INS)-aided navigation system. In the proposed employment scenario, GPS information is not available, the location and structure of a reference landmark is known to a high degree of precision, and the initial navigation states (along with their respective uncertainties) of the vehicle are known to a variable degree of uncertainty. The landmark environment is modeled in advance using commercially available Computer Aided Design (CAD) software and photographs of objects within the scene. This information is intended to be combined with INS data in a statistically-rigorous predictive rendering algorithm to determine error states for implementation in an Unscented Kalman Filter (UKF). The error states are then used to correct the navigation solution. Several methods of exploiting the available information are compared to determine “best performers” in terms of speed, precision, and situational appropriateness. For this research, all methods are based on a proposed Statistical Predictive Rendering (SPR) technique which consists of constructing synthetic views of the scene from the perspective of the vehicle for comparison with actual images from the on-board camera. This predictively-rendered image is then compared to measured images using either feature-based or pixel-based comparison methods which serve to improve the accuracy of the correspondence search technique employed. Vision-aided navigation solutions are an active area of research that incorporates knowledge from the estimation, image processing, and navigation fields of engineering. Past efforts have focused on stochastically constraining feature point correspondence in successive images of the ground from the perspective of an overflying air vehicle using an Extended Kalman Filter (EKF) or UKF, and SPR in the problem of autonomous aerial refueling using an EKF. The proposed algorithm elements are tested using a combination of experimental and simulated data. Currently, the simulated flight profiles show that the navigation solution accuracy and robustness is improved by including SPR-based visual information into the tightly coupled framework. Further experimental tests will be conducted in our laboratory using realistic scenes and in-flight as part of a Test Pilot School project. Conclusions regarding the performance of the tightly-coupled SPR technique will be presented.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85001235","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507343
M. Steen, P. Schachtebeck, Marita Kujawska, P. Hecker
The rapid evolution of inertial Micro-Electro-Mechanical System (MEMS) sensors offers the opportunity to replace expensive conventional Air Data Inertial Reference Units (ADIRU) in future aircraft navigation systems. Particularly with the advent of modernized GNSS and multi-constellation systems, the expected performances of future GNSS-aided Attitude and Heading Reference Systems (G-AHRS) are supposed to satisfy the current requirements. Since MEMS exhibit limitations in their accuracy nowadays, detailed investigations are needed to evaluate the possibility of using them within G-AHRS and also for navigation in the short, mid or long term. This papers deals with the usability of MEMS sensors with current and expected future performance. This evaluation was done based on real flight test data and simulation of future MEMS sensors. While current MEMS cannot completely fulfill all needed requirements, future sensors are expected to satisfy them.
{"title":"Analysis and evaluation of MEMS INS/GNSS hybridization for commercial aircraft and business jets","authors":"M. Steen, P. Schachtebeck, Marita Kujawska, P. Hecker","doi":"10.1109/PLANS.2010.5507343","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507343","url":null,"abstract":"The rapid evolution of inertial Micro-Electro-Mechanical System (MEMS) sensors offers the opportunity to replace expensive conventional Air Data Inertial Reference Units (ADIRU) in future aircraft navigation systems. Particularly with the advent of modernized GNSS and multi-constellation systems, the expected performances of future GNSS-aided Attitude and Heading Reference Systems (G-AHRS) are supposed to satisfy the current requirements. Since MEMS exhibit limitations in their accuracy nowadays, detailed investigations are needed to evaluate the possibility of using them within G-AHRS and also for navigation in the short, mid or long term. This papers deals with the usability of MEMS sensors with current and expected future performance. This evaluation was done based on real flight test data and simulation of future MEMS sensors. While current MEMS cannot completely fulfill all needed requirements, future sensors are expected to satisfy them.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86300249","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507230
Xin Chen, F. Dovis, M. Pini
In this paper a novel multipath mitigation architecture for satellite navigation receiver, named Coupled Amplitude Delay Lock Loops (CADLL) is presented. This architecture exploits the “turbo principle” to separately track the Line Of Sight (LOS) signal and multipath signals in order to mitigate the effects of the multiple reflections. The Delay Lock Loop (DLL) and the Amplitude Lock Loop (ALL) are two basic elements in the structure. DLL is in charge of estimating and tracking the code delay of a specific ray in the incoming signal while ALL is in charge of estimating the corresponding amplitude. A pair of DLL and ALL makes a Unit, devoted to track LOS or a multipath signal. Several Units are incorporated in the CADLL structure, that is then able to track the different component rays from the overall incoming signal, and wiping them off from the received signal. The feedback architecture of the CADLL boosts the performance of the estimation and wipe-off process. CADLL is shown to have good performance in terms of accuracy of estimating and tracking LOS and multipath as well as the robustness to cope with severe multipath scenario.
{"title":"An innovative multipath mitigation method using coupled amplitude delay lock loops in GNSS receivers","authors":"Xin Chen, F. Dovis, M. Pini","doi":"10.1109/PLANS.2010.5507230","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507230","url":null,"abstract":"In this paper a novel multipath mitigation architecture for satellite navigation receiver, named Coupled Amplitude Delay Lock Loops (CADLL) is presented. This architecture exploits the “turbo principle” to separately track the Line Of Sight (LOS) signal and multipath signals in order to mitigate the effects of the multiple reflections. The Delay Lock Loop (DLL) and the Amplitude Lock Loop (ALL) are two basic elements in the structure. DLL is in charge of estimating and tracking the code delay of a specific ray in the incoming signal while ALL is in charge of estimating the corresponding amplitude. A pair of DLL and ALL makes a Unit, devoted to track LOS or a multipath signal. Several Units are incorporated in the CADLL structure, that is then able to track the different component rays from the overall incoming signal, and wiping them off from the received signal. The feedback architecture of the CADLL boosts the performance of the estimation and wipe-off process. CADLL is shown to have good performance in terms of accuracy of estimating and tracking LOS and multipath as well as the robustness to cope with severe multipath scenario.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77752139","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507208
F. Schubert, T. Jost, P. Robertson, R. Prieto-Cerdeira, B. Fleury
Multipath propagation is still one of the main error sources for many GNSS applications. The introduction of new GNSS signals of Galileo and the modernized GPS, for example, will provide higher signal bandwidths which alleviate the disruptive effects of multipath propagation. To study the influences of highly time-variant channels on GNSS tracking performance, simulations of various environments and signal combinations have to be considered. Many signal studies are based on correlation function simulation techniques. Yet to simulate GNSS signal processing with respect to multipath channels, the time-domain simulation approach serves as the most realistic and accurate but also as the most complex and computationally demanding method. This paper presents the further development of the time-domain GNSS simulation tool SNACS and its extension with additional modulations and GNSS coding schemes. Furthermore, a newly developed loss-of-lock detection method is presented and its performance is evaluated using SNACS.
{"title":"Evaluating tracking performance and a new carrier-to-noise estimation method using SNACS","authors":"F. Schubert, T. Jost, P. Robertson, R. Prieto-Cerdeira, B. Fleury","doi":"10.1109/PLANS.2010.5507208","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507208","url":null,"abstract":"Multipath propagation is still one of the main error sources for many GNSS applications. The introduction of new GNSS signals of Galileo and the modernized GPS, for example, will provide higher signal bandwidths which alleviate the disruptive effects of multipath propagation. To study the influences of highly time-variant channels on GNSS tracking performance, simulations of various environments and signal combinations have to be considered. Many signal studies are based on correlation function simulation techniques. Yet to simulate GNSS signal processing with respect to multipath channels, the time-domain simulation approach serves as the most realistic and accurate but also as the most complex and computationally demanding method. This paper presents the further development of the time-domain GNSS simulation tool SNACS and its extension with additional modulations and GNSS coding schemes. Furthermore, a newly developed loss-of-lock detection method is presented and its performance is evaluated using SNACS.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91499733","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507261
K. Sun, L. Presti
In this paper, the problem of acquiring weak Global Navigation Satellite System (GNSS) signals of the next generation systems (such as Galileo and GPS modernization) is addressed and analyzed, focusing the majority of the attention to the problem of managing the higher sign reversal transition rate due to the navigation message in the data channel and to the secondary code in the pilot channel. It must be considered that in case of Galileo E1 Open Service (OS) signals, in each period of the primary spreading code the presence of a potential bit sign reversal can reduce the correlation gain. Moreover, the sign transition occurred on the block of samples being processed produces a Cross Ambiguity Function (CAF) peak splitting along the Doppler shift axis of the search space matrix constructed during the acquisition stage and it may lead to a wrong Doppler estimate. Here, a new two steps acquisition strategy has been proposed in order to mitigate the CAF peak impairments. To circumvent the limitations of the conventional acquisition approaches, differentially coherent detection scheme has been considered to achieve better acquisition sensitivity for a fixed signal-to-noise ratio (SNR). When two steps acquisition strategy is employed in the differentially coherent detection scheme, the bit sign transition problem can be solved and much improved acquisition sensitivity can be obtained specifically in a severe weak signal environment. The validity and effectiveness of the proposed two steps differentially coherent acquisition technique will be deeply assessed with simulation campaigns in terms of detection and false alarm rates, which will be presented by means of Receiver Operating Characteristic (ROC) curves in comparison with the state-of-the-art acquisition approaches.
{"title":"A differential post detection technique for two steps GNSS signal acquisition algorithm","authors":"K. Sun, L. Presti","doi":"10.1109/PLANS.2010.5507261","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507261","url":null,"abstract":"In this paper, the problem of acquiring weak Global Navigation Satellite System (GNSS) signals of the next generation systems (such as Galileo and GPS modernization) is addressed and analyzed, focusing the majority of the attention to the problem of managing the higher sign reversal transition rate due to the navigation message in the data channel and to the secondary code in the pilot channel. It must be considered that in case of Galileo E1 Open Service (OS) signals, in each period of the primary spreading code the presence of a potential bit sign reversal can reduce the correlation gain. Moreover, the sign transition occurred on the block of samples being processed produces a Cross Ambiguity Function (CAF) peak splitting along the Doppler shift axis of the search space matrix constructed during the acquisition stage and it may lead to a wrong Doppler estimate. Here, a new two steps acquisition strategy has been proposed in order to mitigate the CAF peak impairments. To circumvent the limitations of the conventional acquisition approaches, differentially coherent detection scheme has been considered to achieve better acquisition sensitivity for a fixed signal-to-noise ratio (SNR). When two steps acquisition strategy is employed in the differentially coherent detection scheme, the bit sign transition problem can be solved and much improved acquisition sensitivity can be obtained specifically in a severe weak signal environment. The validity and effectiveness of the proposed two steps differentially coherent acquisition technique will be deeply assessed with simulation campaigns in terms of detection and false alarm rates, which will be presented by means of Receiver Operating Characteristic (ROC) curves in comparison with the state-of-the-art acquisition approaches.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84527770","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 : 2010-05-04DOI: 10.1109/PLANS.2010.5507188
Zhen Zhu, S. Bhattacharya, M. Uijt de Haag, W. Pelgrum
This paper focuses on using an image-based optical sensor (e.g. a digital camera) to estimate relative position and attitude without the explicit dependence on Inertial measurement Unit (IMU) gyro measurements, thus, avoiding sensitivities to gyro drift errors. The method uses a priori known point features and is an alternative to existing resection methods used in photogrammetry that can be easily integrated with previously developed tight optical integration (TOI) method. The key principle involved in this approach is the application of geometric constraints derived from multiple point features and multiple views. The envisioned application of this method is cooperative urban navigation, for ground and airborne vehicles.
{"title":"Using single-camera geometry to perform gyro-free navigation and attitude determination","authors":"Zhen Zhu, S. Bhattacharya, M. Uijt de Haag, W. Pelgrum","doi":"10.1109/PLANS.2010.5507188","DOIUrl":"https://doi.org/10.1109/PLANS.2010.5507188","url":null,"abstract":"This paper focuses on using an image-based optical sensor (e.g. a digital camera) to estimate relative position and attitude without the explicit dependence on Inertial measurement Unit (IMU) gyro measurements, thus, avoiding sensitivities to gyro drift errors. The method uses a priori known point features and is an alternative to existing resection methods used in photogrammetry that can be easily integrated with previously developed tight optical integration (TOI) method. The key principle involved in this approach is the application of geometric constraints derived from multiple point features and multiple views. The envisioned application of this method is cooperative urban navigation, for ground and airborne vehicles.","PeriodicalId":94036,"journal":{"name":"IEEE/ION Position Location and Navigation Symposium : [proceedings]. IEEE/ION Position Location and Navigation Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87164353","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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