Recent content by 9988776655

  1. 9

    I Integrating Discrete Data for Navigation: A Comprehensive Guide

    I followed your link and I think that the trapezoidal rule will be useful. I am a MATLAB beginner so I will have to use Java. I am still confused about the integral though.
  2. 9

    I Integrating Discrete Data for Navigation: A Comprehensive Guide

    I have values for the variables (C, v, g, w at all sample points) but I do not know how to evaluate the integral. This equation is supposed to be implemented on a computer as part of a larger algorithm for navigation purposes. I have a feeling that the gyroscope sensor reading and or the...
  3. 9

    Differentiate trigonometric equation

    Hi, Sorry for not being specific enough. You can write y = (Ua - Ub)' * C * r; then find 1) ∂y/∂θ 2) ∂y/∂Φ 3) ∂y/∂ψ so find three separate derivatives. Yes I see that (Ua - Ub)' is constant.
  4. 9

    Differentiate trigonometric equation

    Homework Statement a) Differentiate the following equation with respect to: 1) θ 2) Φ 3) ψ (Ua - Ub)' * C * r where: C is a 3 x 3 rotation matrix: [ cos θ cos ψ, -cos Φ sin ψ + sin Φ sin θ cos ψ, sin Φ sin ψ + cos Φ sin θ cos ψ] [ cos θ sin ψ, cos Φ cos ψ + sin Φ sin θ sin...
  5. 9

    Finding roll, pitch and yaw angles

    Homework Statement I have three angles that relate the sensory body frame to the Earth centered Earth fixed frame: roll_ecef, pitch_ecef, yaw_ecef I have the longitude and latitude. Find the roll, pitch and yaw angles that relate the sensor body frame to the local North East Down frame...
  6. 9

    Statistics - Finding standard deviation of an angle

    As per the first post: s_e = \sqrt{s_{e1}^2 + s_{e2}^2 – 2*cov_{e1e2}}\\s_n = \sqrt{s_{n1}^2 + s_{n2}^2 – 2*cov_{n1n2}} Where: s_{n1} = North standard deviation of position of point 1 s_{n2} = North standard deviation of position of point 2 s_{e1} = East standard deviation of position of point...
  7. 9

    Statistics - Finding standard deviation of an angle

    If I understand this correctly, because in my example x = -d_n (the distance in the north direction between two points) then dx = -1 We had d(atan2(y/x)) = -y / (x^2 + y^2) dx + x / (x^2+y^2) dy To get the variance, would I just ignore dx and dy in this calculation? how to I combine the rules...
  8. 9

    Statistics - Finding standard deviation of an angle

    According to Wikipedia it is required to use partial derivatives to differentiate atan2(y/x): d(atan2(y/x)) = -y / (x^2 + y^2) dx + x / (x^2+y^2) dy The rules for propagation are here: https://en.wikipedia.org/wiki/Propagation_of_uncertainty I can use the rules to propagate something^2 and...
  9. 9

    Statistics - Finding standard deviation of an angle

    Homework Statement Find the formula for the standard deviation (s_h) of heading angle, given the north and east standard deviation of position of two points (s_n1, s_e2, s_n2, s_e2), each point's north-east covariance (s_cov_ne_1, s_cov_ne_2) and the north and east distance between them (d_n...
  10. 9

    Coordinate transformation - NED and ECEF frames

    R(North East Down frame to Earth Centered Earth Fixed) = [ sinLatitude*cosLongitude; -sinLongitude; -cosLatitude*cosLongitude] [-sinLatitude*sinLongitude; cosLongitude; -cosLatitude*sinLongitude] [cosLatitude; 0...
  11. 9

    Coordinate transformation - NED and ECEF frames

    Hi, I have a reference device that outputs euler angles, which are angles that relate the sensor body frame to the north east down frame. These angles are called pitch roll and yaw. The sensor is an accelerometer. I know how to get the rotation matrix that will put accelerations from the...
  12. 9

    Coordinate transform from sensor to North East Down frame

    I am using an algorithm that transforms from my sensor frame to North West Up and I want to instead use North East Down. I have attached the current algorithm. I also want to skip the first step in my algorithm. Here is the current algorithm: http://www.filedropper.com/transformationalgorithm...
  13. 9

    How Can a Kalman Filter Estimate Distance Using GPS and Velocity Data?

    Yes that is what I want to measure
  14. 9

    How Can a Kalman Filter Estimate Distance Using GPS and Velocity Data?

    Hi. Thanks for your advice. I posted something very similar to this in the general engineering forum where I explained my notation: https://www.physicsforums.com/threads/kalman-filter-help-me-to-set-up-a-state-equation.785573/ My version is slightly different because I assumed constant Jerk. I...
  15. 9

    Kalman filter - help me to set up a state equation

    The distance should just be the best estimation possible, given my observations. I know the GPS can have much error. The accelerometers can't give readings in the NED frame without transformation using Euler angles. Euler angles are available from the system but I will use the magnitude of...
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