Recently, application of electronics to construction machinery has proceeded rapidly, and various measuring techniques have been required for a large number of electronic control or monitoring systems.Measurement of true velocity notwithstanding the existence of shoe or wheel slips is one of them. Microwave Doppler radar is an ideal measuring method for the purpose and has been used in automotive applications for many years. However, these vehicular radars don’t provide satisfactory results in typical operating conditions of construction machinery. And there remains a lot of problems to be solved. For example, the relative error at low velocity of 1km/h or so must be reduced.In this paper, solutions of these problems based on data of the field computer simulations and mathematical analyses are described. This study led to the conclusion that the radar’s performance can be highly improved.