An ablation sensor which can measure receded and thermally decomposed fronts of an ablative heatshield is developed by implementing two measurement principles into a single sensor unit. Difficulties in our previously proposed prototype sensor are overcome by fabricating an ablative rod on which optical fibers can be placed, and by producing a resistive circuit composed only of a polymeric material and resistive wire with low temperature coefficients. The present ablation sensor is tested in an arcjet wind tunnel by embedding it into a polyimide impregnated carbon based ablative material. The results demonstrate that the two ablation fronts can be measured simultaneously by using the proposed sensor concept.