1 INTRODUCTION
2 LIGER
2.1 Updates and improvements
2.2 Simulations
2.3 Mock Euclid-like catalogues
2.4 Validation
3 MONOPOLE MOMENT OF THE POWER SPECTRUM
3.1 The galaxy power spectrum in real space
3.2 Definition of the monopole moment in redshift space
3.3 Application to mock surveys
3.4 Bias and scatter of $\hat{P}_{0}(k)$
4 RESULTS
4.1 Real space
4.2 Wide-angle effects: accuracy of the Kaiser factor
4.3 Gravitational lensing and other relativistic effects
4.4 Are these effects measurable?
4.5 The finger of the observer effect
5 SUMMARY