Multi-Receiver GPS-based Direct Time Estimation for PMUs

Bhamidipati, S.R., Ng, Y., Gao, G.X.


29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016), Portland, Oregon, September 2016, pp. 833-837.


Modern power distribution systems are incorporating Phasor Measurement Units (PMUs) to measure the instantaneous voltage and current phasors at different nodes in the power grid. These PMU devices depend on GPS for precise time and synchronization. However, GPS L1 C/A signals are vulnerable because of its low power and unencrypted signal structure. Therefore, there is a need for the development of robust time transfer techniques to ensure power grid stability. We propose a novel multi-receiver direct time estimation (MRDTE) algorithm by utilizing the measurements from multiple receivers triggered by a common clock. We first implement a novel signal processing technique known as the Direct Time Estimation (DTE) that directly correlates the received GPS signal with the corresponding signal replica for each of the pre-generated set of clock states. The most optimal set of clock candidates is then estimated based on the principle of maximum likelihood estimation. By leveraging upon the known geographical diversity of multiple receiver positions, we employ a overall Kalman Filter to obtain a robust corrected clock bias and clock drift at any instant. We demonstrate the increased resilience of our MRDTE algorithm against malicious timing attacks that include jamming and meaconing through outdoor field experiments.

Received Best Presentation of the Session Award.

Related Technologies

Copyright Notice

This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

  1. The following copyright notice applies to all of the above items that appear in IEEE publications: "Personal use of this material is permitted. However, permission to reprint/publish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from IEEE."

  2. The following copyright notice applies to all of the above items that appear in ACM publications: "© ACM, effective the year of publication shown in the bibliographic information. This file is the authorís version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in the journal or proceedings indicated in the bibliographic data for each item."

  3. The following copyright notice applies to all of the above items that appear in IFAC publications: "Document is being reproduced under permission of the Copyright Holder. Use or reproduction of the Document is for informational or personal use only."