 Theoretical discussion and field tests illustrate their feasibility and equivalence in overall positioning performance, which have the maximum horizontal position drifts  less than 2\% of the total travelled distance.
<meaning-changed>  Theoretical discussion and field tests illustrate their feasibility and equivalence in overall positioning performance, which have the maximum horizontal position drifts  less than 2\% of the total travelled distance.
 Theoretical discussion and field tests illustrate their feasibility and equivalence in overall positioning performance, which have the maximum horizontal position drifts are all less than 2\% of the total travelled distance.