• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.737-745
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• 2010

This paper describes the operation results of the GPS receiver system for KSLV (Korea Space Launch Vehicle)-I on the launch site at Naro Space Center that is the first spaceport of South Korea located at Goheung. All equipments of KSLV-I including the GPS receiver system should be monitored and controlled through hard-wired interface during KSLV-I is on standby at the launch pad. The GPS receiver for KSLV-I is connected to triple almost omni-directional patch antennas mounted on the cylindrical surface of KSLV-I that should be erected vertically on the launch pad until lift-off. Signal interference and multipath effects observed in the GPS receiver on the launch site are analyzed in this paper based on the GPS signals received from each GPS antenna.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.152-157
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• 2013

In this paper, we represent the implementation and performance analysis of vector tracking loop based GPS receiver for jamming environment. The vector tracking loop navigation performance is compared by simulation with conventional tracking loop. The simulation results shows that vector tracking loop is more robust than conventional tracking loop in jamming environment. The vector tracking loop can gain 2dB in jamming performance capability over a conventional GPS receiver. Also, Anti-jamming performance of INS Doppler aiding and deep integration method are compared.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.10
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• pp.1073-1080
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• 2008

A GPS receiver platform has been developed to design an interference rejection filter and the platform is also able to evaluate performance of those filters. This platform consists of RF/IF part, data acquisition part and PC part. The RF/IF part converts RF signals to IF signals, the data acquisition part transmits the IF signals to PC using USB device. The PC part rejects the interferences with a filter and then it does navigation with GPS software receiver. The RF/IF part and data acquisition part had been validated with signal spectrum, and the PC part had been validated with the navigation results of GPS receiver. Finally, the entire platform including interference rejection filter has been confirmed with the navigation results in case that the GPS signals and interference entered this platform. As a result, the GPS receiver operated well against interference with 45dB JSR.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.158-165
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• 1990

We have developed a L1 band (1575.42 MHz), C/A (Coarse/Acquisition) code GPS (Global Positioning System) receiver for precise time comparison and evaluated the performance of the receiver. The GPS measurements have been carried out between cesium clocks onboard the GPS satellites and the master clock of Korea Standards Research Institute (KSRI) using the GPS receiver. An accuracy of time transfer better than 100ns was obtained.

• Journal of Advanced Navigation Technology
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• v.1 no.1
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• pp.11-22
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• 1997

Determination of position, velocity and time from the satellite signals is the central problem of the GPS receiver. Generally, GPS receiver uses least square method for navigation filter algorithm. The Kalman filter has known as an optimal linear estimator, which uses the knowledge of the system dynamics and the statistical characteristics of the system noises and measurement error. In this paper, we design an 8 state Kalman filter for GPS navigation and employ some techniques that can reduce computational burden, increase numerical stability, and improve filtering performance. To show its effectiveness, the designed filter is implemented in a GPS receiver and tested in real-time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.101-108
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• 2005

The GPS(Global Positioning System) receiver for satellite launch vehicles which will be mounted on a launch vehicle can be applied to the flight safety system with its accurately calculated position and velocity data during vehicle's flight. This paper analyzes the performance of the GPS receiver such as SNR(Signal to Noise Ratio), fix mode, position and velocity error, number of visible and tracking satellites, and PDOP(Position Dilution of Precision) under temperature variation which is changed from -34$^{\circ}C$ to +71$^{\circ}C$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.329-337
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• 2007

This paper deals with electromagnetic tests of the GPS receiver system that should be developed to satisfy emission and susceptibility requirements for a satellite launch vehicle. Performance of the GPS receiver system against electromagnetic environment that is improved through several tests satisfies all requirements about electromagnetic tests. The outline of the electromagnetic tests and emission test results of CE102, CE106 and RE102 on MIL-STD-461E are described in Part I.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.338-346
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• 2007

This paper deals with electromagnetic tests of the GPS receiver system that should be developed to satisfy emission and susceptibility requirements for a satellite launch vehicle. The performance of the GPS receiver system against electromagnetic environment that is improved through several tests satisfies all requirements about electromagnetic tests. The susceptibility test results of CS101, CS114, CS115, CS116 and RS103 on MIL-STD-461E are described in Part II.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.793-800
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• 2010

GPS spoofing is an intentional interference which uses the mimic GPS signals to fake the receivers. The generic GPS receiver is hard to recognize the spoofing signal because the spoofer generates the fake signals as close as possible to the GPS signal. So the spoofer can do critical damage to public operations. This paper introduces a basic concept of spoofing and analyzes the effect of the spoofing signal to the GPS receiver. Also for stand-alone GPS receivers, two anti-spoofing methods are implemented : RAIM based method and the SQM based method. To evaluate the performance of anti-spoofing method, the software based spoofing signal generator and GPS signal generator are implemented. The performance of the anti-spoofing methods obtained using the output of the software based GPS receiver shows that SQM based method is more effective when multiple spoofing signals exist.

• Journal of Power System Engineering
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• v.14 no.1
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• pp.5-10
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• 2010

Both the accuracy and stability of the clock get from the GPS receiver are considered in the range of pps. And we verified the system clock stability of a micro-controller system using the pps pulse supplied by the GPS receiver. In complex system of digital processing, the rack of precise timing signal may cause the serious problem or breakdown accident. To get rid of these undesirable problems, we introduced VCXO circuit to a micro-controller system to preserve high accurate clock stability.