float solution for LAMBDA

Discussion in 'GPS Technical Discussion' started by venky_vish, Oct 3, 2014.

  1. venky_vish

    venky_vish

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    Hello Everyone

    I am researching on LAMBDA implementation to calculate the integer ambiguity.
    y = Aa + Bb
    y is the observed double difference for each epoch .
    A is the design matrix with normalized LOS vector
    B is a diagonal matrix of the wavelength .

    As a first step I calculate the float solution and I need help with this.
    The model used are popular ones referred by P.J. de Jonge ,CCCJM Tiberius and Teunissen

    This is a sample y vector DD of code and phase
    1.e+5*
    0.0004
    -0.0009
    -0.0007
    -0.0000
    -1.9138
    -1.0779
    0.0778
    0.2645



    Question :
    1. Can I just take y * y' (i,e y * y transpose ) to calculate the variance Qy?
    Else please advice me on the method.

    2.Is there a sample code with numerical examples including actual GPS data that calculate the float ambiguities and variance matrix?

    I tried but covariance matrix Qa had a huge value order of e^10!

    thanks
     
    venky_vish, Oct 3, 2014
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  2. venky_vish

    Jhabindra Khanal

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    Hello sir,
    venky_vish,
    I want to know that how did u use satellites to form single and double difference. I saw in your question there is a DD phase vector. could you provide me the line of mat-lab code for doing double difference . ?? and how to form numerically double difference to find float solution??
    thanks in advance
     
    Jhabindra Khanal, Nov 11, 2015
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