  A novel instantaneous GNSS ambiguity resolution approach which makes use of
only single-frequency carrier phase measurements for ultra-short baseline
attitude determination is proposed. The Monte Carlo sampling method is employed
to obtain the probability density function of ambiguities from a
quaternion-based GNSS-attitude model and the LAMBDA method strengthened with a
screening mechanism is then utilized to fix the integer values. Experimental
results show that 100% success rate could be achieved for ultra-short
baselines.
