Difficult Problems for the New Type Onshore Radio Navigation System of High-accuracy

New type onshore radio navigation system has a high precision of location, using production of satellitic radio navigation system similar to GPS. especially pseudo random phasic coding technique. Inevitably, some technically difficult problem must be solved, including the variety of speed about tropospheric propagation, the sky wave disturbance and the near-far problem. Analyzing the theory of these factors, quantificationally numeration is provided. Finally, the approach of the difficult problems will be given.