The LMRs' Role
The Critical Factor: Communications Systems
The various benefits of the "family" LMR system expressed so far still rely on one critical factor: communication. Direct line of sight is not an option for the LMR "family" as a whole. However, within the LMR system, direct line of sight offers an excellent means of maintaining a constant link between medium and small LMRs.
The limited range of direct line of sight implies that the small and medium LMRs cannot be separated by too great of a distance. Although this is not a significant probelm given the mobility of the medium LMR, it may be more efficient to spread the small LMRs over a greater distance at particular large sites of interest. To achieve this, it the small LMRs will form a radio-based network, and bounce their data off each other to the medium LMR. This multiplies the maximum distance between the farthest LMR from the medium LMR by an approximate factor of five. It is important to note that the limits of communication would not be pushed too far by such a network system. The medium LMR would still need to have an autonomous control system capable of monitoring the small LMRs to ensure that they do not fall out of range at any time.
Long range communication with the base can be achieved through relays which are deposited by the medium LMR to maintain a constant link between the "family" and base. This system has many disadvantages, one of which is the need to design relays small enough to fit on the medium LMR and to be easily deployed at regular intervals.
The solution is to equip the medium sized LMRs with a communication system capable of forming a satellite link with one of the communication satellites installed over Mars for Mission 2004. This would offer a high-bandwidth link to the base and, more importantly, to Earth. As research into radio-modems evolves, it is probable that the radio links between small and medium LMRs will also attain high-bandwidth capacities. The limits on the flow of data from small to medium LMRs could be quite effectively reduced given time and research. This would allow our "family" system to communicate effectively with the humans at conceivably any distance from the base. The satellite system intended for Mission 2004 will be capable of maintaining such a communications link.Continue
Copyright © 2000 Massachusetts Institute of Technology
Comments and questions to firstname.lastname@example.org Last updated: 10 December, 2000