Leonid Savkin FPGA-based Regenerative Electronic Systems in the Spacecrafts Bauman Moscow State Technical University Савкин Леонид Васильевич Памяти моего брата Сергея

Requirements FDIR (Fault Detection, Isolation and Recovery) 1.Hardware redundance -Execution of programs on different hardware modules; -Reservation of software modules. 2.Program redundance 3. Information redundance Three types of redundance: -Exceeding of amount of information over its information entropy; -Application of codes with detection and correction of errors. Fundamental Principle: Redundance -Reservation of onboard hardware subsystems. 2 2

INTEGRATION OF RADIO-ELECTRONIC EQUIPMENT This tendency consists in use of the uniform and centralized methods of digital information processing. The main information processing is carried out in the onboard integrated computing systems which are reserved at the level of subsystems. The number of external modules of information processing is substantially reduced. 3 3 The first tendency: Two tendencies in building onboard equipment of the modern spacecrafts

INCREASE OF HOMOGENEITY OF THE HARDWARE ARCHITECTURES 4 4 The second tendency: Unit of Reliability Support: - determination of existence errors in input data and count of statistics of the errors; - block majority of data; - synchronization of data, processing and controls; - formation of a code of statistics and its transmission to system for operating control; - signal transmission of telemetry in the central onboard computer; - formation of the testing mode. Application of the universal (or unified) the functional modules Two tendencies in building onboard equipment of the modern spacecrafts

RES = transition from high level reconfiguration to low level reconfiguration а) high level reconfiguration b) low level reconfiguration 5 5 What is Regenerative Electronic Systems (RES)?

-Today it isn't enough such FPGA, but development are actively carried. This FPGA technology will allow to realize creation of systems which will partially imitate regeneration process, watched in biological systems. Certainly, it is very rough analog. -This approach in finite approximation allows to speak about implementation of the fault- tolerant systems consisting of two environments interacting among themselves: the functional environment and the controlling environment. Each of these environments can be rebuilt in a deep way in the course of adaptation of main systems to failure of difficult type. What main electronic component basis of RES? 6 6 The main electronic component basis of RES is the programmable logic integrated circuits FPGA class with dynamic reconfiguration+parrying of failures at the level of the configured logic block (for example, as at radiation tolerant FPGA)

1. Island architecture FPGA The inner pattern FPGA is formed on the basis of two types of matrixes which topology of logical and switching inter-element couplings provides an opportunity both involvements of the configurable logic block (CLB) in logic arithmetical process, and a possibility of its switch-off by means of the programmable electronic keys (PEK). 2. Hierarchical architecture FPGA The second FPGA known type is hierarchical FPGA. There is a calculation on the fact that in the diagram there are always sections which interact with each other more tightly, than with the remote modules of the project. Here it is quite simple to connect neighboring CLB, it is necessary not many switches and the turning-out communications work quickly. Here if larger block of calculators is necessary, then the signal shall quit on higher level of hierarchy and then come deep into into the adjacent area. 7 7 Two types of FPGA architecture

8 8 Multi-level reconfiguration in the RES The principle of formation of the conditional hardware levels in a uniform reconfigurable computing field (RCF) of the RES.

9 9 Monitoring of the RES hardware levels Each functional element of RES can be described configuration function of a look: Involvement function: What algorithm for testing of the RES hardware levels to select?

10 Combinative Diagrams and Graphs Separation of a subgraph in the form of a tree from a combinative diagram fragment: The number of subgraphs in the main graph G can vary!!! Digraph of RES Fragment

11 !!! And it is unimportant how value changes : from 0 on 1, or from 1 on 0 !!! Derivative of the Boolean function on a binary variable : Step 1. it is possible to define a Boolean function And let for the digraph Step 2. it is possible to write as Generally By means of the equation it is possible to find such variables (all but ) when in case of value change will change function value Therefore the derivative of the Boolean function is often written as: Step 3. We will take indicator function which allows to localize failure existence in the : а) there is a failure: b) there is no failure: Step 4. The Random test for RES with use of a derivative Boolean function can be written in the form of dependence: Here H – randomization parameter; – random check of digraphs. For the digraph of the RES fragment Algorithm for Testing the RES Fragments (option) (without reviewing ).

1. Regenerative electronic systems are one of the perspective directions in creation of spacecrafts fault-tolerant onboard systems. 2. The principal advantage of these systems is the possibility of restoration and reconfiguration of onboard systems at low hardware level. This circumstance allows to speak about implementation of multi-level reconfiguration of onboard systems. This fact in turn allows to adapt onboard systems to difficult type failures. 3. Difficulty in practical implementation of regenerative electronic systems is connected in very narrow nomenclature of the FPGA with dynamic reconfiguration. But in a number of the countries these researches are actively carried. 4. Prospects of further operation is research the methods of interaction of the functional and controlling environments in the RES. Besides, theoretical and practical interest is represented by development of effective control and diagnostics methods of the RES hardware levels. In this area are also a lot of interesting ways. 12 Conclusions and Prospects

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