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Discretionary access control equipment for differential subsystems


Discretionary access control (DAC) equipment (DAC-E – encoding, DAC-D – decoding) is designed for implementation of discretionary access to differential correction data (protection from unauthorized use) of GNSS (Global Navigational Satellite Systems) differential subsystems.

Discretionary access control equipment

Correction data (CD) security is ensured by their encoding before being transferred to Control & Correction Station (CCS) of GNSS differential subsystem with further decoding upon their receipt by consumer navigation equipment (CNE).

Scheme of GNSS Differential Subsystems

The structural scheme of DAC equipment CCS & CNE installation is given below.

Scheme of DAC equipment CCS installation 

Scheme of DAC equipment CNE installation

DAC-E encodes correction data transferred from Control & Correction Station in a form of binary sequence frames and transfers the encoded data to the transmitter through the modulator.

Consumer navigation equipment receives encoded correction signals and decodes them with the use of DAC-D.
Discretionary access mode is achieved through various code numbers (access levels) assigned to each DAC-D product.

Technical Characteristics

Microcontroller AT89S8252 or AT89S8253
Consumed power 5 W
Supply voltage AC ~220 V
DC – 10 - 30 V
Interface RS-232
Data encoding algorithm GOST 28147-89
Data rate up to 9600 bps
Construction stand alone unit
Size 115*90*55 mm
115*65*55 mm
125*80*40 mm
Weight 400 - 700 g

Contact information:
Information Security Department
phone: +7 (495) 784 - 63 - 77