Analyse the Integrate and Dump (I&D) values with GOOSE

• This page explains how to get I&D values from GOOSE and analyze it.

Follow the page Getting started with the GOOSE Embedded Platform Version3 till check if everything works fine

Start the receiver program with I&D option (--log-iq) enabled

• As an example: Type ogre_console --gps-l1 --galileo-e1 --cold-start --log-iq

  • Let the program run for the required time.

• Stop the program. Hereby, the IQ logging files are saved in the directory where the receiver program is started. Make sure that the 3D position fix was reached, e.g. the last pvt_calculation message shall contain "precision":"3D" as shown here:

  • {"sw_version":"ogre-1.23.0-32-g5957dcc","timestamp":1580984243.0,"hw_timestamp":1143892528,"protocol":"OGRP1_2","time_status":"GPS_SYNCED","time_reference":"GPST","id":"pvt_calculation","pvt_calculation":{"number_of_satellites":11,"clock_bias":-1.0760544714296045e-8,"clock_drift":-1.8517944230802876e-9,"vdop":1.7236504051508619,"hdop":1.2943215834432318,"pdop":2.155513646568661,"tdop":1.4150871120292908,"gdop":2.578509378531543,"ggto":0.0,"coordinate_system":"WGS84","precision":"3D","position":{"x":49.48652375447037,"y":11.128518776409067,"z":390.3327189888805},"velocity":{"x":-0.03059991071132162,"y":0.016238697572242227,"z":0.04240383307568105}}}

• Note: If no 3D fix is reached, IQ values don't have a Gaussian distribution.

• IQ data is saved in the directory where the receiver program is started i.e.

  • Write IQ data: 20200206_111705_channel_1.ogrp
  • Write IQ data: 20200206_111705_channel_2.ogrp
  • Write IQ data: 20200206_111705_channel_3.ogrp
  • Write IQ data: 20200206_111705_channel_4.ogrp
  • Write IQ data: 20200206_111705_channel_5.ogrp
  • Write IQ data: 20200206_111705_channel_6.ogrp
  • Write IQ data: 20200206_111705_channel_7.ogrp
  • Write IQ data: 20200206_111705_channel_8.ogrp
  • Write IQ data: 20200206_111705_channel_9.ogrp
  • Write IQ data: 20200206_111705_channel_10.ogrp
  • Write IQ data: 20200206_111705_channel_11.ogrp

• Analyze each channel (satellite) by plotting Early Prompt Late replicas and their corresponding histogram i.e. ./plot_iq.py 20200206_111705_channel_1.ogrp

Analyse the results

• Early replica

• Prompt replica

• Late replica

• Energy of Early, Prompt and Late replicas

• Code and Carrier Doppler

• Histogram of Early

• Histogram of Prompt

• Histogram of Late

• Above result shows stable tracking, energy of prompt is high and energy of early is equal to that of late. The distribution of correlation values are Gaussian.