rus
Issue #9/2018
Kuznetsov Alexander S., Grishin Alexander G., Tatarchyk Ivan A., Grigoryev Ilya D.
Test Bench for LSN Navigation Modules
Test Bench for LSN Navigation Modules
The article gives a detailed description of the test bench for navigation modules of the local navigation system, as well as the design of the nodes of the test bench. Test scenarios for LSN navigation modules have been described.
Теги: base stations fpga global navigation satellite systems (gnss) local navigation system prototype of local navigation system transceiver modules базовые станции глобальные навигационные спутниковые системы (гнсс) локальная система навигации макет системы лсн плис приемопередающие модули
While developing navigation modules and local navigation system’s reference stations, there arises an issue of testing their operation within a completed system, processing software, inspecting their accuracy and operational characteristics, as well as new techniques of navigational system synchronization and self organization. For solving these problems a test bench for navigation modules of LNS system has been developed.
The bench includes units of LNS radio-navigation field formation, synchronization and subscriber unit. Each of the units includes transmit/receive modules (TRM). TRM are based on pairing units from the computing unit: evaluation kit using FPGA Zynq-7000 AP SoC ZC706 Evaluation Kit FPGA of Xilinx and TRM radio frequency microcircuit AD9361 installed on mezzanine card extension for FPGA AD-FMCOMMS3-EBZ. To increase the level of emitted signal, to switch radio links AD9361 to the antenna and to filter signals received, the mezzanine card extension for FPGA AD-FMCOMMS3-EBZ is connected with the card that filters, magnifies and switches radio frequency LNS signal, the latter card has been developed by JSC “NIIMA “Progress”. FPGA Zynq-7000 of Xilinx with connected microcircuit AD9361 installed on the mezzanine card and the card performing filtering, magnification and radio frequency LNS signal switching, are placed into aluminium package for shielding them from external electromagnetic interference and weather impacts.
To supply test bench elements with power in the field environment and to provide high stable clock signal generation, corresponding power supply and clocking modules have been developed. Lead-acid accumulators Delta series DT with 7Ah capacity and 12V voltage were used as power supply elements, enabling TRM to work in stand-alone mode up to 10 hours. Operation from mains supply 220V with automatic battery charging has also been provided. As a highly stable clock generator, temperature controlled “Morion” GK-142ТС oscillators have been used. Power supply and clocking modules are installed in packages of IP65 standard by dust- and moisture protection.
For FPGA Zynq-7000 of Xilinx an IP-core has been designed, which describes VLSI of TRM digital tract in local navigation system К1917ВС014, developed by JSC “NIIMA “Progress”, which is the base for all navigation modules in LNS, with due account of operation with radio frequency microcircuit AD9361 and software used for navigation modules and reference stations. The developed software enables organizing LNS operation in various variants of the system design. Thus complete test bench identity with navigation module has been attained at separate VLSIs produced by JSC “NIIMA “Progress”.
For bench assemblies accommodation we have made a geodetic tie of 5 points on the field of Moscow К. А.Timiryaziev Agricultural Academy: 4 points by rectangular corners for reference stations accommodation and one point in the centre for receiving module accommodation. Points have been tied by means of high precision Trimble geodetic receivers.
For inspecting navigation modules of LNS and reference stations one of the bench assemblies is substituted by the tested device, and simulation of LNS operation is carried out. For inspecting navigation modules of LNS the tested device is placed near the bench subscriber unit and measured coordinates of the subscriber unit are compared with the known coordinates. For inspecting reference stations one of the assemblies in the LNS module of radio navigation field formation is substituted by the tested device and signals receipt at the subscriber unit and the accuracy of determining its own coordinates are checked.
The paper provides a detailed description of test bench components and the results of LNS modules experimental investigations.
The bench includes units of LNS radio-navigation field formation, synchronization and subscriber unit. Each of the units includes transmit/receive modules (TRM). TRM are based on pairing units from the computing unit: evaluation kit using FPGA Zynq-7000 AP SoC ZC706 Evaluation Kit FPGA of Xilinx and TRM radio frequency microcircuit AD9361 installed on mezzanine card extension for FPGA AD-FMCOMMS3-EBZ. To increase the level of emitted signal, to switch radio links AD9361 to the antenna and to filter signals received, the mezzanine card extension for FPGA AD-FMCOMMS3-EBZ is connected with the card that filters, magnifies and switches radio frequency LNS signal, the latter card has been developed by JSC “NIIMA “Progress”. FPGA Zynq-7000 of Xilinx with connected microcircuit AD9361 installed on the mezzanine card and the card performing filtering, magnification and radio frequency LNS signal switching, are placed into aluminium package for shielding them from external electromagnetic interference and weather impacts.
To supply test bench elements with power in the field environment and to provide high stable clock signal generation, corresponding power supply and clocking modules have been developed. Lead-acid accumulators Delta series DT with 7Ah capacity and 12V voltage were used as power supply elements, enabling TRM to work in stand-alone mode up to 10 hours. Operation from mains supply 220V with automatic battery charging has also been provided. As a highly stable clock generator, temperature controlled “Morion” GK-142ТС oscillators have been used. Power supply and clocking modules are installed in packages of IP65 standard by dust- and moisture protection.
For FPGA Zynq-7000 of Xilinx an IP-core has been designed, which describes VLSI of TRM digital tract in local navigation system К1917ВС014, developed by JSC “NIIMA “Progress”, which is the base for all navigation modules in LNS, with due account of operation with radio frequency microcircuit AD9361 and software used for navigation modules and reference stations. The developed software enables organizing LNS operation in various variants of the system design. Thus complete test bench identity with navigation module has been attained at separate VLSIs produced by JSC “NIIMA “Progress”.
For bench assemblies accommodation we have made a geodetic tie of 5 points on the field of Moscow К. А.Timiryaziev Agricultural Academy: 4 points by rectangular corners for reference stations accommodation and one point in the centre for receiving module accommodation. Points have been tied by means of high precision Trimble geodetic receivers.
For inspecting navigation modules of LNS and reference stations one of the bench assemblies is substituted by the tested device, and simulation of LNS operation is carried out. For inspecting navigation modules of LNS the tested device is placed near the bench subscriber unit and measured coordinates of the subscriber unit are compared with the known coordinates. For inspecting reference stations one of the assemblies in the LNS module of radio navigation field formation is substituted by the tested device and signals receipt at the subscriber unit and the accuracy of determining its own coordinates are checked.
The paper provides a detailed description of test bench components and the results of LNS modules experimental investigations.
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