Reliable gold code generators for GPS receivers

Abstract

This paper 1 examines five strategies for upset protection in Gold sequence generators used to maintain signal acquisition in GPS receivers. This work is motivated by the increased prevalence of single-event upsets in ultra low-power GPS receivers. If any upset occurs in the Linear Feedback Shift Register (LFSR) modules, then the corresponding satellite signal must be re-acquired, resulting in high energy expenditure and time delay. We evaluate the performance and complexity of methods based on error correction and modular redundancy.

Improving the Performance of the Carrier Tracking Loop for GPS Receivers in Presence of Transient Errors due to PVT Variations

“…Using expressions (10) and (14), the tracking error variance of the carrier loop, when transient errors appear in the frequency discriminator (i.e N θ = 0), can be estimated for different values of carrier filter bandwidths. Both simulated results (markers) and theoretical estimates (solid lines) are shown in Fig.…”

“…This power spectral density is used in conjunction with (10) to find the tracking error variance when the frequency discriminator is faulty. The variance of δω, denoted δ 2 δω , is given by…”

“…GPS receivers are widely used in mobile context, and there is motivation to minimise power consumption and maximise battery life in these devices. In [10] and [11], strategies have been proposed and evaluated for upset protection in the Gold sequence generators and the Numerically Controlled Oscillator (NCO) respectively. The authors of [12] presents two approaches to deal with internal logic upsets inside correlation process used in the tracking process of GPS receivers.…”

Demo: Localisation in a faulty digital GPS receiver

“…Position given by a noiseless GPS receiver X(t) (color orange), by a faulty GPS receiver without adding the fault tolerant technique (color red), by a faulty GPS receiver when using the fault tolerant technique (color blue), displayed using Google earth in order to have a complete GPS receiver (Radio Frequency and digital processes). Although, fault tolerant techniques that have been proposed in [5], [6] and [7] to protect, respectively, the Gold code generator, the the Numerically Controlled Oscillator and the correlation will be implemented in the noisy receiver to evaluate the robustness of the complete GPS receiver against transient errors. An ASIC will replace the FPGA target once the study of the trade-off between the complexity and the performance of the GPS receiver is achieved.…”

Interference Mitigation for 5G Millimeter-Wave Communications

“…Popular communication systems typically use code domain for interference cancellation. For instance, Wi-Fi, CDMA2000, and Global Positioning System (GPS) use Barker codes [22], a combination of Walsh and Gold codes [23], and long Gold codes [24], respectively. The key advantage of spread spectrum modulation is immunity to noise and multipath distortion, including interference mitigation.…”