diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4c6e396c3..0a21c9461 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -56,7 +56,7 @@ stages:
 # Stage "test"
 
 observables-test-180417100529:
-  image: debian:9.3-slim
+  image: ubuntu:bionic
   stage: test
   tags:
   when: manual
@@ -69,7 +69,9 @@ observables-test-180417100529:
     - cmake -DENABLE_UNIT_TESTING_EXTRA=ON -DENABLE_SYSTEM_TESTING_EXTRA=ON ..
     - NPROC=$(grep -c ^processor /proc/cpuinfo)
     - make -j$(($NPROC+1))
+
     # Execute Unit Tests
+    - export DISPLAY=unknown
     - echo "Running HybridObservablesTest for GPS L1 CA..."
     - ../install/run_tests --gtest_filter=HybridObservablesTest* -PLL_bw_hz_start=25.0 -DLL_bw_hz_start=1.5  -PLL_narrow_bw_hz=10.0 -DLL_narrow_bw_hz=0.75 -disable_generator=1 -enable_external_signal_file=1 -signal_file=/captures/gitlab_test_signals/static/180417100529.A_L1E1_12500000Hz_ichar.dat -fs_gen_sps=12500000 -skip_samples=125000000 -external_signal_acquisition_threshold=4.0 -extend_correlation_symbols=5 -external_signal_acquisition_doppler_step_hz=10 -trk_test_implementation=GPS_L1_CA_DLL_PLL_Tracking --show_plots=0 -filename_rinex_obs=/captures/gitlab_test_signals/static/true_data_180417100529/rinex_obs/rinex-obs_V1_A1-static_vehicle.txt -skip_trk_transitory_s=30 --gtest_output=xml:test_results.xml
 
@@ -83,16 +85,14 @@ observables-test-180417100529:
     - ../install/run_tests --gtest_filter=HybridObservablesTest* --PLL_bw_hz_start=30.0 --DLL_bw_hz_start=1.0 --disable_generator=1 --enable_external_signal_file=1 --show_plots=true --fs_gen_sps=12500000 --skip_samples=125000000 --external_signal_acquisition_threshold=2.2 --trk_test_implementation=Galileo_E5a_DLL_PLL_Tracking --external_signal_acquisition_doppler_step_hz=10  --show_plots=0 --signal_file=/captures/gitlab_test_signals/static/180417100529.A_L5E5_12500000Hz_ichar.dat --filename_rinex_obs=/captures/gitlab_test_signals/static/true_data_180417100529/rinex_obs/rinex-obs_V1_A1-static_vehicle.txt --skip_trk_transitory_s=5 --gtest_output=xml:test_results.xml
 
     - mv *.xml ../build64/
-    - mv position_test*.txt ../build64/
     - cd ..
     - rm -rf build-test
   artifacts:
     paths:
       - build64/*.xml
-      - build64/*.txt
 
 position-test-180417100529:
-  image: debian:9.3-slim
+  image: ubuntu:bionic
   stage: test
   tags:
   when: manual
@@ -106,6 +106,7 @@ position-test-180417100529:
     - NPROC=$(grep -c ^processor /proc/cpuinfo)
     - make -j$(($NPROC+1))
     # Execute System Tests
+    - export DISPLAY=unknown
     - ../install/position_test -config_file_ptest=/captures/gitlab_test_signals/static/gnss-sdr_180417100529.A_L1E1.conf -static_scenario=0 -use_pvt_solver_dump=1 -use_ref_motion_file=1 -ref_motion_filename=/captures/gitlab_test_signals/static/true_data_180417100529/motion_V1.csv -pvt_solver_dump_filename=./PVT_pvt.dat -show_plots=0 
     - mv *.xml ../build64/
     - mv position_test*.txt ../build64/
@@ -117,7 +118,7 @@ position-test-180417100529:
       - build64/*.txt
 
 run-tests-arm:
-  image: debian:9.3-slim
+  image: debian:buster-slim
   stage: test
   tags:
     - arm