Context : TheassessmentofthefrequencyofplanetarysystemsreproducingtheSolarSystem ’ sarchitectureisstillanopenprobleminexoplanetaryscience.Detailedstudyofmultiplicityandarchitectureisgenerallyhamperedbylimitationsinquality , temporalextensionandobservingstrategy , causingdifficultiesindetectinglow-massinnerplanetsinthepresenceofoutergiantplanetarybodies .

Aims : Wepresenttheresultsofhigh-cadenceandhigh-precisionHARPSobservationson20solar-typestarsknowntohostasinglelong-periodgiantplanetinordertosearchforadditionalinnercompanionsandestimatetheoccurencerate f _ { p } ofscaledSolarSystemanalogs , i.e.systemsfeaturinglower-massinnerplanetsinthepresenceoflong-periodgiantplanets .

Methods : WecarryoutcombinedfitsofourHARPSdatawithliteratureradialvelocitiesusingdifferentialevolutionMCMCtorefinetheliteratureorbitalsolutionsandsearchforadditionalinnerplanets.Wethenderivethesurveydetectionlimitstoprovidepreliminaryestimatesof f _ { p } .

Results : Wegenerallyfindbetterconstrainedorbitalparametersfortheknownplanetsthanthosefoundintheliterature ; significantupdatescanbeespeciallyappreciatedonhalfoftheselectedplanetarysystems.Whilenoadditionalinnerplanetisdetected , wefindevidenceforpreviouslyunreportedlong-periodmassivecompanionsinsystemsHD50499andHD73267.Wefinallyestimatethefrequencyofinnerlowmass ( 10-30M _ { \oplus } ) planetsinthepresenceofoutergiantplanetsas f _ { p } < 9.84 \% forP¡150days .

Conclusions : Ourpreliminaryestimateof f _ { p } issignificantlylowerthanthevaluesfoundintheliteratureforsimilarlydefinedmassandperiodranges ; thelackofinnercandidateplanetsfoundinoursamplecanalsobeseenasevidencecorroboratingtheinwardmigrationformationmodelforsuper-Earthsandmini-Neptunes.Ourresultsalsounderlinetheneedforhigh-cadenceandhigh-precisionfollow-upobservationsasthekeytopreciselydeterminetheoccurenceofSolarSystemanalogs .