Device for automatic documentation of crash scenes
First Claim
1. A portable system for automatically documenting crash scenes comprising:
- a measurement unit for measuring the position of crash scene element points and for collecting and processing raw satellite signal measurement data including a GPS receiver means, a GPS antenna means, a receiver I/O means, a DC/DC power converter means, a power supply means, and a portable computer means; and
a reference unit for collecting, storing, and outputting raw satellite signal measurement data used for removing ranging signal distortions that are common to signals received at both the reference and measurement units, including a GPS receiver means, a GPS antenna means, a receiver I/O means, a data logger means, and a DC/DC power converter means.
1 Assignment
0 Petitions
Accused Products
Abstract
Crash scene measurement, documentation, and analysis is used to determine crash dynamics and causes in order to determine fault, liability, and prevention methods. The device to be patented is a low cost, compact system that significantly enhances the speed and accuracy of crash scene documentation, and it is applicable to aviation, highway, railway, and vessel crashes. The system will use highly accurate, kinematic, Differential Global Positioning System (DGPS) measurements to locate crash scene elements and reference points with a relative measurement error of less than two centimeters (0.79 in.). Using a government DGPS reference signal (National DGPS, US Coast Guard) or locating the reference module on a geodetic marker, allows the absolute location of the scene to be determined with an error of between three to five meters. Once the scene is measured, the device automatically develops accurate dimensions, scene drawing, and a standard report of the crash.
227 Citations
14 Claims
-
1. A portable system for automatically documenting crash scenes comprising:
-
a measurement unit for measuring the position of crash scene element points and for collecting and processing raw satellite signal measurement data including a GPS receiver means, a GPS antenna means, a receiver I/O means, a DC/DC power converter means, a power supply means, and a portable computer means; and
a reference unit for collecting, storing, and outputting raw satellite signal measurement data used for removing ranging signal distortions that are common to signals received at both the reference and measurement units, including a GPS receiver means, a GPS antenna means, a receiver I/O means, a data logger means, and a DC/DC power converter means. - View Dependent Claims (2, 3, 5, 6, 7, 8, 9)
-
-
4. A method, for automatically documenting data from a crash scene using a measurement unit multimedia user interface comprising the steps of:
-
i. guiding a user through the process for measuring crash element points, ii. designating and labeling crash element points and recording information associated with the crash scene, iii. controlling and collecting data from a GPS receiver, iv. collecting and storing GPS measurement data, v. initiating GPS measurement data processing, vi. controlling software for Computer Aided Design (CAD) drawing to develop a drawing of the scaled crash scene, vii. controlling software to develop a crash report consisting of textual data recorded about the crash scene and scene elements. - View Dependent Claims (10, 11, 12, 13)
i. initializing the Kalman Filter with an approximate first solution, ii. calculating satellite orbital positions at measurement times from raw GPS data, iii. selecting satellite signals from all available to achieve the optimum solution, iv. calculating expected ranges between the satellites and trial measurement antenna positions, and the known or assumed reference antenna position, v. determining a model of the carrier phase observables by calculating the expected carrier phase measurement corresponding to the expected satellite-to-antenna ranges, vi. removing measurement errors common to the reference and measurement units'"'"' data by combining the measured carrier phase from each, synchronized by GPS measurement time, vii. modeling the removal of measurement errors common to the reference and measurement units'"'"' data by combining the expected carrier phase from each, viii. calculating the best solution for the observed data using an iterative process of predicting a trial solution based on statistical models and comparing it with the observed data, ix. converting the Earth Centered Earth Fixed (ECEF) position to a position in a local coordinate system centered at the reference unit'"'"'s antenna, x. developing a file of crash element positions in local coordinates that is in a format that can be read by a CAD program to create an accurately scaled representation of the crash scene, xi. refining the statistical models in the Kalman Filter as preparation for the next set of measurements based on the correlation of the actual data with the model at the last measurement time, xii. monitoring of solution characteristics to determine its integrity and level of accuracy, and xiii. reinitializing the Kalman Filter when the solution integrity has been determined to have degraded beyond acceptable levels for the designed system'"'"'s accuracy.
-
-
12. A method for automatically documenting data in accordance with claim 11, further comprising the steps of selecting from visible satellites based on orbital position relative to the scene and any observables or figures-of-merit provided by the GPS receiver indicating the presence or absence of signal distortions.
-
13. A method for automatically documenting data in accordance with claim 4, further comprising the step of augmenting the GPS measurement of the scene elements with measurements made by other means such as a laser range finder, tape measure, or wheel measure by correlating the measurements with any GPS determined position.
-
14. A method for automatically determining a crash scene dimensions from raw GPS data comprising the steps of:
-
i. synchronizing reference and measurement module data from measuring crash element points, ii. checking for inaccurate measurements, iii. scaling and transforming the measurements, iv. determining accurate position solution using Kalman Filter techniques, v. validating and reinitializing the filter, if required, with an independent least square comparison, vi. converting the Earth Centered Fixed positions to local scene dimensions, and vii. formatting a CAD drawing file.
-
Specification