1. A method of processing a signal comprising the steps of: (i) receiving the signal at a set of n loci, (ii) measuring the phase of the signal at each locus to produce a set of n sequential phase values; (iii) calculating the differences between neighboring phase values in the sequence according to: 
 DIFF 1 k =Φmeasured k+1 −Φmeasured k ( k= 1 to n− 1) where Φmeasured k is the kth phase value in the sequence; (iv) calculating the differences between neighboring values of DIFF1 k according to: 
 DIFF2 k =DIFF1 k+1 −DIFF1 k ( k= 1 to n− 2) (v) rounding the values of DIFF2 k to the nearest integral multiple of complete phase cycles to produce the set of rounded values DIFF k ; (vi) summing neighboring values in the set of rounded values DIFF k to provide a set of values, dΦ k , according to: 
 dΦ k+1 =dΦ k +Diff k 
 dΦ 1 =0 (k=1 to n−2) (vii) summing neighboring values of dΦ k to give the set of values Φ k according to: 
 Φ k+1 =Φ k +dΦ k 
 Φ 0 =0 (k=1 to n−1) and (viii) adding the values Φ k to the corresponding values Φmeasured k to produce the unwrapped phase values.