Combining multiple GPS receivers to enhance relative distance measurements

2013 ◽  
Author(s):  
E. Trinklein ◽  
G. Parker
Keyword(s):  
Relative Distance ◽  
Distance Measurements ◽  
Gps Receivers

Regulating a Formation of a Large Number of Vehicles

2005 ◽  
Author(s):  
Akira Okamoto ◽  
Dean B. Edwards
Keyword(s):  
Control Problem ◽  
Coordinate System ◽  
Formation Control ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Relative Distance ◽  
Control Algorithms ◽  
Distance Measurements ◽  
Six Degree Of Freedom

Various control algorithms have been developed for fleets of autonomous vehicles. Many of the successful control algorithms in practice are behavior-based control or nonlinear control algorithms, which makes analyzing their stability difficult. At the same time, many system theoretic approaches for controlling a fleet of vehicles have also been developed. These approaches usually use very simple vehicle models such as particles or point-mass systems and have only one coordinate system which allows stability to be proven. Since most of the practical vehicle models are six-degree-of-freedom systems defined relative to a body-fixed coordinate system, it is difficult to apply these algorithms in practice. In this paper, we consider a formation regulation problem as opposed to a formation control problem. In a formation control problem, convergence of a formation from random positions and orientations is considered, and it may need a scheme to integrate multiple moving coordinates. On the contrary, in a formation regulation problem, it is not necessary since small perturbations from the nominal condition, in which the vehicles are in formation, are considered. A common origin is also not necessary if the relative distance to neighbors or a leader is used for regulation. Under these circumstances, the system theoretic control algorithms are applicable to a formation regulation problem where the vehicle models have six degrees of freedom. We will use a realistic six-degree-of-freedom model and investigate stability of a fleet using results from decentralized control theory. We will show that the leader-follower control algorithm does not have any unstable fixed modes if the followers are able to measure distance to the leader. We also show that the leader-follower control algorithm has fixed modes at the origin, indicating that the formation is marginally stable, when the relative distance measurements are not available. Multi-vehicle simulations are performed using a hybrid leader-follower control algorithm where each vehicle is given a desired trajectory to follow and adjusts its velocity to maintain a prescribed distance to the leader. Each vehicle is modeled as a three-degree-of-freedom system to investigate the vehicle’s motion in a horizontal plane. The examples show efficacy of the analysis.

scholarly journals Improved GPS-based Satellite Relative Navigation Using Femtosecond Laser Relative Distance Measurements

2016 ◽  
Vol 33 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Hyungjik Oh ◽  
Han-Earl Park ◽  
Kwangwon Lee ◽  
Sang-Young Park ◽  
Chandeok Park
Keyword(s):  
Femtosecond Laser ◽  
Relative Distance ◽  
Relative Navigation ◽  
Distance Measurements

The sensing of relative distance.

1956 ◽  
Author(s):  
Walter C. Gogel
Keyword(s):  
Relative Distance

Perceived size-distance measurements for a moving stimulus

1997 ◽  
Author(s):  
Maurice Hershenson ◽  
Orit Markowitz
Keyword(s):  
Distance Measurements ◽  
Moving Stimulus

Searching in the Center: Do Guinea-Pigs Encode Relative Distance?

2006 ◽  
Author(s):  
Sylvain Fiset
Keyword(s):  
Guinea Pigs ◽  
Relative Distance
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