Lapan-A2 Satellite, also known as LAPAN-ORARI, is the second satellite developed by Indonesian National Institute of Aeronautics and Space (LAPAN) especially Satellite Technology Center. This was launched in 2015 which one payloads for amateur radio communication such VR (Voice Repeater) APRS (Automatic Packet Reporting System). The a method transmitting messages, status positions using certain...

Nominal signal deformations are present in GNSS-GPS and WAAS-GEO satellite signals. They result in pseudorange errors, which in turn cause navigation errors for GNSS users. These navigation errors depend on the userand reference-receiver configuration parameters as well as satellite geometry and user location. Previous papers by the authors focused on obtaining a better understanding of the pse...

We investigate the following problem proposed by Alcatel. A satellite sends information to receivers on earth, each of which is listening on a chosen frequency. Technically, it is impossible for the satellite to precisely focus its signal onto a receiver. Part of the signal will be spread in an area around its destination and this creates noise for nearby receivers on the same frequency. Howeve...

In receiver-initiated MAC protocols for Wireless Sensor Networks (WSNs), communication is initiated by the receiver of the data through beacons containing the receiver’s identity. In this paper, we consider the case of a network intruder that captures and replays such beacons towards legitimate nodes, pretending to have a fake identity within the network. To prevent this attack we propose RAP, ...

Recent advances in the US GPS constellation have resulted in additional signals being made available for both military and civil applications. The modernized GPS signal structure now includes signals broadcast on three frequencies with both the legacy GPS modulation codes, additional civilian codes, and also additional military codes on L1 and L2. In the next few years, GNSS users will also be ...

Rendezvous and Multi-channel Hidden Terminal problems are the two well-known challenges in developing a multi-channel MAC protocol. In literature, the Control Period Based (CPB) approach is proposed to cope with the rendezvous problem. Each channel is partitioned into several beacon intervals and each of which consists of ATIM window and data window. All hosts are asked to stay in every ATIM wi...

The paper proposes a distributed and adaptive algorithm for movement of nodes in a MANET (mobile adhoc network) to maintain the routing path to establish a secure connection between any two nodes at any instant of time. The proposed algorithm assumes the presence of a GPS receiver at each node. Relative position and velocity of each node in the network are measured with respect to its neighbors...