This paper presents a research work to develop a navigation technique for a class of nano-micro space rocket. Onboard MEMS inertial sensors are used in view of post-flight trajectory estimation. Combined with synchronized measurements of the combustion engine which is of hybrid type and uses N 2 O and PE, we show how the relative redundancy of the data can be used to calibrate a thrust model. Experimental results are presented and stress the numerous difficulties needed to be resolved. Quantitative results are provided along with estimates of the obtained accuracy.