# On Sharing Spatial Data with Uncertainty Integration Amongst Multiple Robots Having Different Maps
## 1 Introduction
### Related Works  
There is a plethora of previous works related to sharing information in multi-robot systems. Sharing corresponding matches of an object by two robots to calculate an accurate relative localization over time is proposed in Reference [2]. Work in Reference [3] proposes sharing visual information. In Reference [4], task negotiation between multiple robots by sharing information is proposed to decide the sequence in which the tasks should be performed by different robots. Work in Reference [5; 6] proposes a protocol to share the region of interest between robots for efficient task cooperation. In-fact,  
Figure 1: Robot R1 finds a new obstacle blocking the path and shares this information with other robots (R1, \(\cdots\), R5). The blue and red ellipses represents the robot’s and obstacle’s positional uncertainty, respectively. multi-robot sport activities like Robo-soccer [7; 8] heavily relies on meaningful information sharing between robots to achieve a common goal. Virtual pheromones have been proposed to be used for coordinating master-slave robots in References [9; 10]. Path planning of multiple robots using information from external security cameras is proposed in Reference [11]. In addition, a direct obstacle coordinate information sharing was proposed in our previous work [12] without considering the uncertainty. However, this is a limitation as in practical systems there is always some uncertainty associated with robot's localized information and mapped obstacle's position due to sensor errors. RoboEarth [13; 14; 15] is another platform which heavily uses information exchange through cloud. Such information sharing has huge merits in robot path planning. Path planning is an active area of research and in the context of multi-robot systems path-planning has shown promising advantages through information sharing between robots. Multi-robot collision avoidance has been discussed in Reference [16]. Work in Reference [17] presents a mechanism in which robots share information about their remaining battery power and accordingly avoid collision by giving priority to a robot with less battery power over the shortest path. An interesting approach of collaborative navigation through visual-servoing is presented in Reference [18; 19] which heavily relies on reliable and efficient inter-robot communication to share information. The proposed work focuses on multiple robots sharing information about the dynamic changes in the remote area of the environment. This enables the robots to use updated and timely information to efficiently plan their paths. Information sharing among multiple robots for efficient path planning usually involves a decentralized approach [20] in which each robot calculates its path individually and decisions to change paths or avoid obstacles is done later based on the received messages from other robots. This is unlike centralized path planners [21] in which all the paths of all the robots are calculated simultaneously. In Reference [22], a motion planner is proposed for multiple robots with limited ranges of sensing and communication to reach the goal in dynamic environments. In Reference [23], a navigational technique for multiple service robots in a robotic wireless network (RWN) is presented in which robots download map information from map servers for safe navigation. Semantic information is used among multiple robots for efficient task coordination in Reference [24]. In Reference [25], a practical case of multi-robot navigation in warehouse has been discussed. The proposed work also deals with the positional uncertainty of robots and obstacles. In this context, a decentralized approach for collaboration between multiple robots in presence of uncertainty are considered for robot action in Reference [26]. A review of multi-robot navigation strategies can be found in References [27; 28; 29]. The proposed work is an extension of our previous work [12]. Our previous work proposed the idea of a 'Node-Map' and obstacle's confidence decay mechanism.