Sensitivity of Track Accuracy to Navigation, Sensor, and Time Errors Within a Distributed System
Abstract
The success of achieving a Single Integrated Air Picture (SIAP) is a function of the accuracy with which the positional estimates of aerospace objects can be made. This report presents a detailed analysis of how track accuracy is affected by navigation, sensor, and time errors, which include errors due to time synchronization, time stamping, time latency, etc. Although the analysis assumes a shipborne sensor system for illustrative purposes, the analysis is general and can be applied to all sensing systems that comprise the distributed system that develops and maintains the SIAP. Navigation errors are the result of errors in the accelerometers and gyroscopes forming the inertial navigation system. The focus here is not on the errors in the individual inertial instruments but on their performance as they affect the uncertainty in the position of the inertial navigation system and the orientation of the navigation reference frame. Navigation positional uncertainty or error is described by error in the north position, east position, and height of the navigation system. Error in the orientation of the navigation reference frame is described by three misalignments that represent the cumulative effect of the gyroscopes' inability to maintain a perfect inertial reference. Errors in navigation position translate directly into errors in track measurement. A 300 m east position error results in a 300 m track error. Navigation misalignments also have a significant effect on track accuracy. A I mrad misalignment about all three navigation reference axes results in a track error of 260 m for objects 100 nm away. The misalignment contribution is proportional to range to the object. Thus, for an object 10 nm from the ship, the 1 mrad misalignment contribution is 26 m.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2004
- Accession Number
- ADA425204