I. INTRODUCTIONThe problem of detec

I. INTRODUCTION
The problem of detecting gases and mapping their con￾centration is relevant to different applications, such as gas
leak detection in industrial areas, surveillance of areas where
hazardous gases might be present and pollution monitoring
in cities. In the past decades, stationary sensor networks
have been largely used to address this problem. Typically,
the sensors used are relatively inexpensive, readily available
and light weight, but they have to be directly exposed to
the target gases (i.e., in-situ sensing), which means that they
provide a point measurement where they are positioned [1].
The nature of the sensors used entails that gas emissions
could go undetected due to sparse measurements and that,
whenever there are changes to the environment where the
network is placed, a new, time-consuming deployment could
be required.
More recently, mobile robots equipped with gas sensors
have proven to be valuable instruments for gas detection
and mapping [2], [3], as they can flexibly adapt to complex
outdoor and indoor environments. Moreover, their use has be￾come even more appealing since the introduction of sensors
which are capable of detecting gases remotely. For instance,
sensors based on tunable diode laser absorption spectroscopy
(TDLAS) [4] allow for ranged sensing up to considerable
distances. However, compared to in-situ sensors, they are
larger and more expensive. Thus, they cannot be distributed
in large numbers in the environment, but they are suitable to
be used on-board a mobile platform

結果 (中文) 3:

一、引言检测气体和映射自己的￾浓度是不同的应用程序相关的问题，如气工业地区的泄漏检测，监测的领域在哪里有害气体可能存在和污染监测在城市。在过去的几十年里，固定传感器网络已在很大程度上用于解决这个问题。通常，所使用的传感器是比较便宜的，现成的重量轻，但他们必须直接接触目标气体（即，原位检测），这意味着他们提供一个点测量，它们被定位[ 1 ]。所使用的传感器的性质，需要的气体排放量可以去未被发现的，由于稀疏的测量和，每当有变化的环境中网络被放置，一个新的，耗时的部署可以被要求。最近，配备了气体传感器的移动机器人已被证明是有价值的气体检测仪器和映射[ 2 ]，[ 3 ]，因为它们可以灵活地适应复杂的室外和室内环境。此外，它们的使用是￾来更有吸引力因为传感器的介绍能远程探测气体。例如,基于可调谐二极管激光吸收光谱的传感器（TDLAS）[ 4 ]允许远程传感到相当距离.然而，相比，在原位传感器，他们更大，更昂贵。因此，他们不能被分配在大量的环境中，但他们是合适的用于车载移动平台