Lorenzo Simone

On-Board PN Ranging Acquisition Based on Threshold Comparison with Soft-Quantized Correlators

Pseudonoise (PN) regenerative ranging on-board acquisition performance is assessed in terms of the acquisition time for a given probability of acquisition at a reference signal-to-noise ratio (SNR). So far the detection of the correct ranging code phase alignment has been analyzed by a maximum likelihood (ML) estimation with no amplitude quantization at the chip matched filter output. Despite its optimality in an additive white Gaussian noise (AWGN) channel, an ML estimation finds a maximum value also when no ranging signal (i.e., noise-only) is present at the receiver input thus resulting in a false alarm (FA) detection. On the contrary a suboptimum threshold comparison estimation of the correct ranging code phase alignment can overcome such a hindrance. This work reports the on-board PN regenerative ranging acquisition performance based on threshold comparison with 3-bits soft-quantized correlators along with the relevant trade-offs with respect to the ML estimation.

Optimized QPSK modulator for DVB-S applications

In this paper the implementation of a multirate QPSK modulator is presented. The modulator architecture has been optimized to reduce the hardware complexity and maximize the carrier frequency in order to meet the requirements of deep space and satellite applications. Finally, the performance has been evaluated by implementing the modulator on a Xilinx XC2V3000 FPGA

Partial reconfiguration in the implementation of autonomous radio receivers for space

In space mission there are different scenarios where autonomous radio systems are very useful. In this paper we consider one of such scenarios, related to the communication infrastructure for the planet exploration. The basic idea is to obtain significant advantages in autonomous radio receiver implementation by using FPGA dynamic partial reconfiguration. Implementing the most significant part of the radio, we will show as this techniques can be used and what are the advantages we can obtain. In particular, by using this design methodology system complexity and power consumption is reduced improving the overall system reliability (mainly, in relation to possible SEU induced by ions in the configuration memory).

Code detection at Launch and Early Orbit Phase for CDMA TT&C

This paper reports the analysis, simulation and algorithm design of a code detection procedure for CDMA TT&C systems under robust Doppler dynamics at launch and early orbit phase.

On-board DSP techniques for Radio-Science applications

This paper reports recent improvements for range and range rate measurements at Ground Station due to on-board digital signal processing techniques that will be used for radio-science experiments within the framework of the BepiColombo mission to Mercury.

A breadboard receiver for proximity link applications: design and test results

This paper presents a Receiver Breadboard for Proximity Link applications, offering an insight into the digital signal processing techniques and including a detailed analysis of the algorithms. A section of the paper will be devoted to the test results in terms of acquisition performance, tracking range and demodulation capabilities.

Compressive sensing spectrum analysis for space autonomous radio receivers

In space mission there are different scenarios where autonomous radio systems are very useful. In this paper we consider one of such scenarios, related to the communication infrastructure for the planet exploration (where different rovers communicate with an orbiter). One of the most critical functions to implement in autonomous radio is the reconstruction of the electromagnetic scenario, detecting the radio emission of the rovers (with the estimate of the frequency of the carrier, the power level and so on) present on the planet surface. In these deep space missions, it is often necessary to analyze a very large bandwidth signal (often more than 1 GHz) where only few small portions of the spectrum are used by narrow-band transmissions. This spectrum characteristic requires the use of high-resolution spectrum analysis, typically performed using FFT based algorithms. Even if this large bandwidth analysis is possible with actual (terrestrial) ADC technology, the space qualification and the constraints on the power consumption make this ADCs unsuitable for space applications. This paper shows as the new paradigm of Compressive Sensing -or Compressive Sampling- (CS) can be exploited to reduce the performance requirements of the ADC used for the spectrum analysis in autonomous radio.

On-board signal acquisition: system trade-offs and implementation

Aim of this paper is to provide an overview of the on-board signal acquisition techniques suited for Deep Space Transponders addressing also mission aspects and implementation issues.

Digital modulator architectures for satellite and space applications

The present paper aims to define viable strategies for implementing flexible and programmable fully digital modulators, able to cope with multiple symbol rates, signal bandwidths, and modulation schemes, using a single analog section (composed by filters and up-converters). This development is applicable both in the field of broadband multimedia communication payloads, as well as in telemetry tracking and command links and also in deep space communications, for which the topics that need to be addressed are essentially the same. However, when state-of-the-art performance is required, it might be needed to separate the developments on the basis of the specific application. An example of a GMSK modulator architecture is also given.

Digital Architecture of Next Generation Spacecraft Tracker Based on Wideband ∆DOR

Tracking signals of an interplanetary spacecraft are distorted by various deep space noise sources and receiver imperfections. In recent years, a new technique called Wideband Delta Direct One-Way Ranging, based on broadband probe signals, was developed. This research work provides an architecture upgrade for the ESA X/Ka Deep Space Transponder, that supports the generation of Wideband DDOR signals. This implementation is envisaged to greatly improve the spacecraft tracking performance and unlock future missions requiring 1 nrad level of angular position accuracy.