Communications: directive radio wave systems and devices (e.g. – Directive – Including a satellite
Reexamination Certificate
1999-08-09
2001-07-10
Tarcza, Thomas H. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a satellite
Reexamination Certificate
active
06259403
ABSTRACT:
BACKGROUND
The three dimensional position coordinates of a mobile object can be determined in a variety of ways. In recent years, the global positioning satellite (GPS) receivers and the receivers that use the alternative satellite systems, like GLONASS system, came of age and began to proliferate widely. An autonomous navigational system that includes a satellite receiver and a navigational computer can achieve the 10-meter level of accuracy in the position determination of a mobile object.
The differential navigation systems that utilize the differential corrections in addition to the satellite signals can determine the positional information with the meter-range accuracy. The real-time kinematic (RTK) GPS systems that are capable of utilizing in real time not only code but also carrier information transmitted from satellites can achieve the centimeter level of accuracy in the position determination of a mobile object.
Recently, the alternative laser based navigational systems were developed by a number of companies. For instance, the IBEO Lasertechnik, based in Hamburg, Germany, developed a Ladar 2D navigational sensor system that is capable of navigating a mobile unit equipped with a scanning and rotating laser beam and a navigational computer. The laser beam is reflected by a number of laser reflectors placed in positions with known coordinates. The Ladar 2D navigational system determines the ranges between the mobile unit and the laser reflectors that reflect the laser beam illuminating them. By solving the simple geometric equations, the navigational computer can determine the mobile unit 2D position coordinates and navigate the mobile unit in real time with accuracy up to 2 cm.
However, the laser reflectors have to be placed in the locations with known coordinates for the laser positioning system to become operational. This requires that the survey of the laser reflectors be performed independently from the navigation of the mobile unit.
What is needed is a satellite navigational system augmented by a laser positioning system that is capable of surveying the laser reflectors and navigation of the mobile unit at the same time.
SUMMARY
The current patent application is novel and unique because it discloses a satellite navigational system augmented by a laser positioning system that is capable of surveying the laser reflectors and navigation of the mobile unit at the same time.
One aspect of the present invention is directed to a positioning system comprising a mobile unit and a plurality of targets further comprising a plurality of visible targets. The mobile unit detects a range information between the mobile unit and each of the visible targets and utilizes the range information to calculate its positional information.
In one embodiment, the mobile unit further comprises: (a) a scanning and rotating laser beacon generating a laser beam; and (b) a satellite positional system (SATPS) further comprising a SATPS receiver; and an integrated laser/SATPS navigational computer.
In one embodiment, the plurality of targets further comprises a plurality of visible GPS satellites, and a plurality of visible laser reflectors placed in locations with known coordinates.
In one embodiment, the plurality of GPS satellites further comprises at least two visible GPS satellites, and the plurality of laser reflectors further comprises at least two visible stationary laser reflectors located in known and fixed positions. The integrated laser/GPS navigational computer utilizes range information between the mobile unit and each visible GPS satellite, and range information between the mobile unit and each visible laser reflector to obtain the mobile unit three-dimensional positional information.
The integrated laser/GPS navigational computer further comprises a database system capable of storing the coordinates of each laser reflector which is used by the integrated laser/GPS navigational computer for identifying each visible laser reflector.
In one embodiment, the plurality of laser reflectors further comprises at least two visible laser reflectors located in known and fixed positions (“known visible laser reflector”) and at least one visible laser reflector located in a position with unknown position coordinates (“unknown visible laser reflector”).
The mobile unit utilizes the range data between the mobile unit and each visible GPS satellite, and between the mobile unit and each visible known laser reflector obtained in at least three consecutive measurements to perform surveying operation of each visible unknown laser reflector and to obtain the mobile unit position coordinates. This allows the user of mobile unit to add each surveyed laser reflector to the set of laser reflectors used for navigation purposes.
In another embodiment of the present invention, each visible laser reflector placed in a position with known coordinates further comprises a laser reflector identification information (ID), and an intelligent reflector (IR) capable of providing its ID upon reflecting the laser beam. The integrated navigational computer utilizes the stored coordinates of each visible laser reflector, the reflector ID information, and the obtained range data between the mobile unit and each visible laser reflector to identify each visible laser reflector.
Another aspect of the present invention is directed to a method of navigation of a mobile unit. The method comprises the steps of: (a) obtaining the range information between the mobile unit and a plurality of visible targets placed in locations with known coordinates, and (b) utilizing the range information for navigation of the mobile unit.
In one embodiment, the step of obtaining the range information further includes the steps of: (a) determining the range data between the mobile unit and at least two visible laser reflectors with known position coordinates, and (b) determining the range data between the mobile unit and at least two visible navigational satellites to achieve the three-dimensional navigation of the mobile unit.
In one embodiment, the step of utilizing the range information for three-dimensional navigation of the mobile unit further includes the steps of: (a) placing at least one visible laser reflector in a visible location with unknown coordinates, (b) determining three-dimensional coordinates of the mobile unit in at least three consecutive locations, (c) determining three-dimensional coordinates of each visible unknown laser reflector, (d) making a new set of visible laser reflectors utilized for three-dimensional navigation purposes by replacing one visible known laser reflector by one visible unknown laser reflector, and (e) determining the three-dimensional coordinates of the mobile unit by measuring the range data between the mobile unit and each visible satellite, and by measuring the range data between the mobile unit and each visible laser reflector using the new set of visible laser reflectors.
REFERENCES:
patent: 5949371 (1999-09-01), Nichols
Mull Fred H
Tankhilevich Boris G.
Tarcza Thomas H.
Trimble Navigation Limited
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