Single-point position estimation in interplanetary trajectories using star trackers

2016 ◽  
Vol 128 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Daniele Mortari ◽  
Dylan Conway
Keyword(s):  
Single Point ◽  
Position Estimation ◽  
Point Position ◽  
Interplanetary Trajectories

The effect of aborting ongoing movements on end point position estimation

2013 ◽  
Vol 231 (3) ◽  
pp. 341-350 ◽  
Author(s):  
Yoshihiro Itaguchi ◽  
Kazuyoshi Fukuzawa
Keyword(s):  
Position Estimation ◽  
Point Position ◽  
End Point

scholarly journals GPS Receiver Position Interpretation using Single Point PVT Estimation Algorithm

2019 ◽  
Vol 9 (2S3) ◽  
pp. 53-57
Keyword(s):  
Nonlinear Equation ◽  
Single Point ◽  
Estimation Algorithm ◽  
Location Information ◽  
Gps Receiver ◽  
Point Position ◽  
Range Observation

In our day-to-day lives, we need to get the correct GPS location information. GPS is based on the calculation of the pseudo-range and four unspecified parameters, but the formula is not linear in navigation observation. A single point position algorithm can solve the nonlinear equation; the algorithm is based on Taylor linearization. This paper provides an overview of the single point PVT algorithm and presents the GPS satellite pseudo-range observation equations, typically over-determined as there are only four unknown satellites, but generally, more than four are monitored and thus more than four pseudo-range observation equations. Single point PVT estimation algorithm is used to solve pseudo range observation equations in order to find position and clock bias solutions are described in detail. In this article, the position of GPS receiver is estimated w.r.t. to X, Y, Z Coordinates, in addition to that clock bias also estimated.

scholarly journals Space State Representation Product Evaluation in Satellite Position and Receiver Position Domain

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3791
Author(s):  
Renata Pelc-Mieczkowska ◽  
Dariusz Tomaszewski
Keyword(s):  
Real Time ◽  
Single Point ◽  
Product Evaluation ◽  
Space Representation ◽  
Satellite Orbits ◽  
Time Service ◽  
Satellite Position ◽  
Point Position ◽  
Broadcast Ephemeris ◽  
The Impact

In Global Navigation Satellite Systems (GNSS) positioning, important terms in error budget are satellite orbits and satellite clocks correction errors. International services are developing and providing models and correction to minimize the influence of these errors both in post-processing and real-time applications. The International GNSS Service (IGS) Real-Time Service (RTS) provides real-time orbits and clock corrections for the broadcast ephemeris. Real-time products provided by IGS are generated by different analysis centres using different algorithms. In this paper, four RTS products—IGC01, CLK01, CLK50, and CLK90—were evaluated and analysed. To evaluate State Space Representation (SSR) products’ GPS satellites, the analyses were made in three variants. In the first approach, geocentric real-time Satellite Vehicle (SV) coordinates and clock corrections were calculated. The obtained results were compared with the final IGS, ESA, GFZ, and GRG ephemerides. The second approach was to use the corrected satellite positions and clock corrections to determine the Precise Point Position (PPP) of the receiver. In the third analysis, the impact of SSR corrections on receiver Single Point Position (SPP) was evaluated. The first part of the research showed that accuracy of the satellite position is better than 10 cm (average 3 to 5 cm), while in the case of clock corrections, mean residuals range from 2 cm to 17 cm. It should be noted that the errors of the satellites positions obtained from one stream differ depending on the reference data used. This shows the need for an evaluation of correction streams in the domain of the receiver position. In the case of PPP in a kinematic mode, the tests allowed to determine the impact that the use of different streams has on the final positioning results. These studies showed differences between specific streams, which could not be seen in the first study. The best results (3D RMS at 0.13 m level) were obtained for the CLK90 stream, while for IGC01, the results were three times worse. The SPP tests clearly indicate that regardless of the selected SSR stream, one can see a significant improvement in positioning accuracy as compared to positioning results using only broadcast ephemeris.

scholarly journals Indoor Positioning Based on Pedestrian Dead Reckoning and Magnetic Field Matching for Smartphones

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4142 ◽  
Author(s):  
Jian Kuang ◽  
Xiaoji Niu ◽  
Peng Zhang ◽  
Xingeng Chen
Keyword(s):  
Magnetic Field ◽  
Estimation Error ◽  
Magnetic Field Gradient ◽  
Single Point ◽  
Dead Reckoning ◽  
Position Estimation ◽  
Shopping Mall ◽  
Mm Algorithm ◽  
Field Matching ◽  
Pedestrian Dead Reckoning

This paper presents an ambient magnetic field map-based matching (MM) positioning algorithm for smartphones in an indoor environment. To improve the low distinguishability of a magnetic field fingerprint at a single point, a magnetic field sequence (MFS) combined with the measured trajectory contour coming from pedestrian dead-reckoning (PDR) is used for MM. Based on the fast approximation of magnetic field gradient, a Gauss-Newton iterative (GNI) method is used to find a rigid transformation that optimally aligns the measured MFS with a reference MFS coming from the magnetic field map. Then, the position of the reference MFS is used to control the position drift error of the inertial navigation system (INS) based PDR by an extended Kalman filter (EKF) and to further improve the accuracy of the trajectory contour. Finally, we conduct several experiments to evaluate the navigation performance of the proposed MM algorithm. The test results show that the position estimation error of the MM algorithm is 0.64 m (RMS) in an office building environment, 1.87 m (RMS) in a typical lobby environment, and 2.34 m (RMS) in a shopping mall environment.

Estimation of the conversion point position in elastic orthorhombic media

Geophysics ◽  
2019 ◽  
Vol 84 (1) ◽  
pp. C15-C25 ◽  
Author(s):  
Shibo Xu ◽  
Alexey Stovas
Keyword(s):  
Real Data ◽  
Processing Parameters ◽  
Position Estimation ◽  
Point Estimation ◽  
Radial Coordinate ◽  
Converted Wave ◽  
Rational Form ◽  
Point Position ◽  
Conversion Point ◽  
Wave Modes

Determination of the conversion point position is very important to carry out seismic processing in the common conversion point gather of converted wave data. The anisotropic effect is very obvious for a converted wave when estimating the physical and processing parameters from real data. To estimate the conversion point in an elastic orthorhombic (ORT) medium, we have defined an explicit rational form approximation for the radial coordinate of the conversion point for converted [Formula: see text], [Formula: see text], and [Formula: see text] waves. To obtain the approximation coefficients, the Taylor series approximation in the corresponding vertical slowness for three pure wave modes is applied. The coefficients in our proposed approximation are computed within two vertical symmetry planes. The difference between the acquisition azimuth and the azimuth of the conversion point position is analyzed for different combinations of the wave modes. The accuracy of the conversion point position estimation for three ORT models is illustrated in the numerical examples. One can see from the results that for converted [Formula: see text] and [Formula: see text] waves, our approximation is very accurate in estimating the conversion point position regardless of the tested ORT model. For a converted [Formula: see text] wave, due to the existence of cusps, triplications, and shear singularities, the error in conversion point estimation is relatively larger compared with PS-waves in the vicinity of the singularity point.

scholarly journals Ego-Lane Index Estimation Based on Lane-Level Map and LiDAR Road Boundary Detection

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7118
Author(s):  
Baoguo Yu ◽  
Hongjuan Zhang ◽  
Wenzhuo Li ◽  
Chuang Qian ◽  
Bijun Li ◽  
...  
Keyword(s):  
Single Point ◽  
Dead Reckoning ◽  
Boundary Detection ◽  
Position Estimation ◽  
Intelligent Vehicles ◽  
Measurement Unit ◽  
Distance Measurements ◽  
Importance Weighting ◽  
Lidar Measurements ◽  
Index Estimation

Correct ego-lane index estimation is essential for lane change and decision making for intelligent vehicles, especially in global navigation satellite system (GNSS)-challenged environments. To achieve this, we propose an ego-lane index estimation approach in an urban scenario based on particle filter (PF). The particles are initialized and propagated by dead reckoning with inertial measurement unit (IMU) and odometry. A lane-level map is used to navigate the particles taking advantage of topologic and geometric information of lanes. GNSS single-point positioning (SPP) can provide position estimation with meter-level accuracy in urban environments, which can limit drift introduced by dead reckoning for updating the weight of each particle. Light detection and ranging (LiDAR) is a common sensor in an intelligent vehicle. A LiDAR-based road boundary detection method provides distance measurements from the vehicle to the left/right road boundaries, which provides a measurement for importance weighting. However, the high precision of the LiDAR measurements may put a tight constraint on the distribution of particles, which can lead to particle degeneration with sparse particle sets. To deal with this problem, we propose a novel step that shifts particles laterally based on LiDAR measurements instead of importance weighting in the traditional PF scheme. We tested our methods on an urban expressway at a low traffic volume period to ensure road boundaries can be detected by LiDAR measurements at most time steps. Experimental results prove that our improved PF scheme can correctly estimate ego-lane index at all time steps, while the traditional PF scheme produces wrong estimations at some time steps.

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