Communications: directive radio wave systems and devices (e.g. – With particular circuit – Display
Reexamination Certificate
2000-10-02
2002-06-04
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
With particular circuit
Display
C342S179000, C342S185000, C342S197000, C345S958000
Reexamination Certificate
active
06400313
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a system and method for transforming multi-sensor data from its measurement coordinates into display grids designed for human display and, more particularly, to a system and method for interpreting and analyzing multi-sensor data.
BACKGROUND OF THE INVENTION
Conventional sensors that create 4-dimensional data include radar, sonar, LIDAR, and many types of medical sensors. These sensors collect data as a series of 1-dimensional rays through the environment as a function of time. Typically, in these conventional systems, a series of such arrays of measurements are made at closely-spaced points in time where each array of measurement is made in a coordinate system determined by the position and orientation of the sensor at the time the measurement is made. Such data can be difficult to interpret in its raw form because the data is often collected in a polar or spherical coordinate system, and because, the sensor's position and/or orientation cannot be precisely controlled at the instant of measurement. The problem of data analysis and interpretation is further compounded by the fact that the sensor's position changes with time. Furthermore, multiple sensors in different locations may provide data each having different characteristics.
Because modern sensors have the ability to collect large numbers of observations per second, there currently exists a need for a system and method to filter the large volume of raw data, determine which parts of the data are needed for a particular display, extract only these relevant portions for processing, and, finally, to display data for interpretation in the observer's chosen coordinate system.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a system and method that can enable an operator to specify what data is of interest and use that specification to process only the data required to synthesize the requested display.
It is another object of the invention to allow historic data and data from multiple sensors to be used to satisfy the operator's display requirements thus obviating the need for additional data measurements by the sensors and allowing more of the sensor's duty cycle to be made available for additional uses.
Operationally, the invention described herein and shown in
FIGS. 1-13
has many benefits and advantages over conventional systems. In particular, most sensors in conventional systems lack the ability to measure data in a format that directly suits an operator's needs. For example, radar measures data in a polar or spherical coordinate system with the origin at the radar's current spatial location. Each sweep of the radar antenna is considered to be a frame of data. In one embodiment of this invention, the operator requires a Cartesian PPI (Plan Position Indicator) for use in planning a navigation strategy. Each radar pulse in the sweep produces an array of data corresponding to range gates out to a maximum range along a 1-dimensional line-of-sight. Generally, one frame of data cannot fill a regular Cartesian grid such as horizontal slice at a constant altitude. Even with an electronically scanned antenna, it is difficult and inefficient use of the sensor's time line to measure explicitly vertical or horizontal slices. Using this method and apparatus, multiple polar sweeps would be taken and then transformed into as many independent planar slices as desired.
Continuing with the example of airborne weather radar as the embodiment of this invention, where the returns from individual pulses from the radar are measurements of power as a function of range, where range is quantified into discrete cells. Each individual return corresponds to a line of sight, or ray, along which the antenna's main lobe is assumed to point and along which the measured targets are assumed to lie. Typically, each such ray has a direction specified by the azimuth and elevation of the ray in the coordinate system determined by the position and attitude of the aircraft at the time the measurement was made.
For many sensor systems (i.e., radar), the rays can be considered to follow essentially straight-line paths. However, many propagation media exhibit refraction or diffraction effects that can cause the rays to deviate from straight lines. As long as there is a deterministic way to characterize this bending, the current invention permits even curved ray paths to be used.
A collection of such rays can be grouped into a frame. In the example of a weather radar with a mechanically scanned antenna, the collection of rays taken during a single scan of the radar with a constant measurement basis makes a logical grouping for a frame. In other instances, other groupings may be more appropriate. In grouping a collection of rays into a frame, it is useful to maintain them in a common local coordinate system. In the case of the aforementioned radar, a logical choice is the coordinate system of the first pulse in the scan. Because this is known at the beginning of the scan, the subsequent pulses can be converted to this coordinate system in real time, as they arrive. This coordinate transformation is determined by the position and orientation of the radar at the time of the measurement and is different for each pulse. In the case of fixed (e.g. ground-based) radar, no coordinate transformation may be necessary.
Once the data is collected into frames, the frames may be saved in a frame database from which they may be accessed for subsequent processing and display. Note that while the individual measurements within a frame have been translated to a common coordinate system within the frame, each frame is stored in the database in a coordinate system that is specific to that individual frame.
The user may access the data in the frame database for subsequent processing or to generate displays. In the example of weather radar, one way in which the data may be accessed is in generating a horizontal or vertical planar slice through the 3-dimensional volume of space being measured. Another way in which the data may be accessed is in generating a voxel image of a 3-dimensional volume of space. Such methods may request data along a regular grid of points in a coordinate system that is independent of the coordinate systems in which the individual frames are stored. Note that the regular grid of points may be in any arbitrary orientation and need not be aligned with any horizontal or vertical.
Ray coordinates from each collection system frame are first transformed from their local measurement coordinate system into the planar grid coordinate system. In this common coordinate system, the ray coordinates are then transformed into a grid analysis space such that the image grid plane is in the x-y plane, and distance out of plane is the z dimension. This is implemented using a single coordinate transformation.
In a typical application, data collected over time by one or more sensors is measured in many different spatial coordinate systems. This can be due to the inherent motion of the sensor itself, or an inability to control the sensor's position to within the measurements spatial precision. Also, when studying the evolution of spatial data in a sequence of displays or data extraction operations, the desired output coordinate system changes continuously. To be useful, data from all relevant measurement frames considered by a human operator or computer algorithm in a single analysis must ultimately be transformed into a single spatial coordinate system. This method implements a sequence of transformations which utilize each individual data frame's measurement coordinate systems and the desired output spatial system to efficiently implement the coordinate conversions.
After applying the coordinate transformations and quantization of the data to the analysis grid, the method can utilize the time (history) dimension to analyze short-term time dependent phenomena and suppress measurement noise. The method also produces indications of which
Brinsley James R.
Morici Martin M.
Honeywell International , Inc.
Sotomayor John B.
Yeadon Loria B.
LandOfFree
Projection of multi-sensor ray based data histories onto... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Projection of multi-sensor ray based data histories onto..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Projection of multi-sensor ray based data histories onto... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2963504