In this paper, implementation of real-time FKP-DGPS algorithm for L1 single-frequency GPS receiver has been carried out by using FKP correction message. One of the typical augmentation systems for L1 singlefrequency GPS receiver is Differential GPS (DGPS). However, in the DGPS, the correlation of the errors experienced at the reference station and the user location is dependent on the distance between them. As the separation of the user from the reference station increases so does the probability of significant differing ionospheric and tropospheric conditions at the two sites. Therefore, bias error is caused by it in DGPS and it is commonly referred to as "Spatial Decorrelation". Up to now, there are Regional Area Augmentation System (RAAS) and WADGPS (Wide Area Differential GPS) as a typical research for L1 single-frequency GPS receiver considering this spatial decorrelation. But, they are not complete system, are developing in KOREA. In other words, there is no way to eliminate spatial decorrelation for single-frequency GPS receiver. FKP is 'Flacchen Korrektur Parameter' in German. It is one of Network-RTK (Network-Real Time Kinematic) methods such as VRS (Virtual Reference Station), MAC (Master-Auxiliary Concept) and it means 'Area Correction Parameters'. It is an information to deal with spatial decorrelation in CDGPS. According to RTCM standard, it can be easily modified to the correction for pseudorange measurements. In Korea, FKP has been being broadcasted in RTCM V3.1 from National Geographic Information Institute since 2012. Thus, to use FKP correction for single-frequency GPS receiver, it is not necessary to add more hardware system and to construct infrastructure. Utilizing the broadcasted FKP correction message, we have constructed real-time FKP-DGPS algorithm and have done static and dynamic tests to verify its performance. In the results, we have confirmed the real-time FKP-DGPS algorithm improves DGPS positioning accuracy. In the case of static, FKP-DGPS has 21% better positioning accuracy (1CEP) than DGPS along with 76% less bias error. In the case of dynamic, FKP-DGPS has 19% better positioning accuracy (1CEP) than DGPS along with 31% less bias error.