midgard.gnss
midgard.gnss.solution_validation
comp_quality_indicators()
Full name: midgard.gnss.solution_validation.comp_quality_indicators
Signature: (sol_vc_mat:numpy.ndarray) -> tuple
Compute quality indicators
Following quality indicators are computed 1. compute the standard error ellipse(SEE) 2. compute the distance root mean squared (DRMS) 3. compute the circular error probable (CEP)
Args:
sol_vc_mat
: Variance-covariance matrix of the unknown
Returns:
Tuple with DRMS, CEP and SEE
compute_dops()
Full name: midgard.gnss.solution_validation.compute_dops
Signature: (az:numpy.ndarray, el:numpy.ndarray, el_mask:float=0, min_num_sats:int=4) -> Tuple[numpy.ndarray, ...]
Compute DOP (dilution of precision)
Args:
az
: Satellite azimuth angle (radians)el
: Satellite elevation angle (radians)el_mask
: Elevation cut-off angle (radians)min_num_sats
: Minimum number of satellites for a valid solution
Returns:
Tuple with GDOP, PDOP, HDOP and VDOP
epilog (str)
epilog = '\n**EXAMPLE**\n sol_validation (residuals, alpha_sign_level n_params)\n args:\n residuals (I): postfit residuals \n alpha_sign_level(I): alpha significance level and defines the rejection area.\n possible values of alpha = 0.05 (95%), 0.01 (99%) and 0.001 (99.9%)\n n_params (I): number of estimated parameters (states).\n \n\nKeywords: Chi-square distribution,\n'
get_my_parser()
Full name: midgard.gnss.solution_validation.get_my_parser
Signature: ()
main()
Full name: midgard.gnss.solution_validation.main
Signature: ()
Main program for testing solution validation implementation
TODO: This should be done via midgard/tests/gnss !!!
prolog (str)
prolog = '\n**PROGRAM**\n solution_validation.py\n \n**PURPOSE**\n Perform Chi-square test for residuals. Degrees of freedom (df) refers to the number of values that\n are free to vary df = number of valid satellites (nv) - number of parameters to be estimated (nx) - 1.\n GNSS solution validation based on the argument alpha, the level of significance (e.g. 99%), and\n defines the rejection level of the crossing events. \n Note that this is different from the false alarm rate, which instead refers to error type I\n \n**USAGE**\n'
sol_validation()
Full name: midgard.gnss.solution_validation.sol_validation
Signature: (residuals:numpy.ndarray, alpha_siglev:float, n_params:int=4) -> bool
Validating the GNSS solution is carried out using Chi-square test
Use Chi-square test for outlier detection and rejection.
Args:
residuals
: Postfit residuals for all satellites in each epochalpha_siglev
: Alpha significance leveln_params
: Number of parameters (states), normally 4 parameters for station coordinates and receiver clock
Returns:
Array containing False for observations to throw away.