NAV SOL Flashcards
What is the INAV in the KC-130J?
GPS INS EGI NAVAIDS Distributed Air Data System (DADS)
Describe an EGI
All functions of the EGI (GPS, INS) are performed in the H-764G, Honeywell EGI.
Each EGI is a 3-axis navigation system that uses data from its own internal accelerometers, laser ring gyros, and GPS
Each provide independent blended solutions.
Location of EGI’s
Both EGI’s are located at the back of FS 245
3 segments of GPS
Space, Control and User Segment
Describe space segment
consists of actual satellite constellation
Describe control segment
consists of a network of monitoring and control facilities used to manage the satellite constellation and update the satellite navigation data messages
Describe user segment
receivers used to process the GPS signals
What is FOM?
FIGURE OF MERIT
FOM is typically calculated as the root-sum-square of the estimated errors contributing to the solution accuracy.
FOM 1-9, FOM 1 indicates best navigation performance
What is EHE?
Estimated Horizontal Error (0-9.99nm)
A measurement of horizontal position error displayed in NM, based upon a variety of factors including Geometrical Dilution of Precision (GDOP) and satellite signal quality.
FOM 1-9 descriptors
- less than or equal to 25 meters
- 26-50 meters
- 51-75 meters
- 76-100 meters
- 101-200 meters
- 201-500 meters
- 501 to 1000 meters
- 1001 to 5000 meters
- greater than 5000 meters
What is INS?
Internal Navigation System
Contains a 3 axis laser ring gyro assembly, and accelerometers
Not susceptible to mechanical drift, align quickly and have low power demands–drift rate is less than 0.8NM per hour
What is EGI?
EGI solution is the primary navigation solution. The solution is the result of optimal mixing of GPS, INS and DADS using a Kalman Filter
What is the Kalman Filter?
The Kalman Filter is a series of algorithms that recursively estimate the error state vector. It also calculates the uncertainty in its estimate as given by its covariance matrix.
