Optical Telemetry Ranging

Abstract

Optical Telemetry Ranging is a ranging scheme conceived for space-to-ground links operating at optical frequencies. Its underlying principle is inherited from Radio Frequency (RF) Telemetry Ranging — generalized phase measurements required to estimate the two-way light-time delay are acquired on board the spacecraft and then telemetered back to Earth. However, and unlike the RF Telemetry Ranging, no dedicated uplink ranging signal is required for the system to operate. Instead, the uplink frame structure is used to define and measure the uplink signal phase. This article describes how Optical Telemetry Ranging can be implemented in current space optical communication systems. To that end, it first describes the concept of operation assuming an idealized link and measurement system where all signals are continuous and can be sampled instantaneously. Then, it explains how the system can be adapted to work within the design of discrete-time optical transmitters and receivers currently under development. Finally, we discuss how to encode phase measurements taken on board the spacecraft and show that the bandwidth overhead incurred in the downlink is, in most cases, negligible.

Keywords

Details

Volume

42-221

Published

May 15, 2020

Pages

1–23

File Size

10.4 MB