Challenge:
To develop a field usable test & evaluation system to perform the functional checks and measurements on integrated airborne Radar.
The Solution:
Using the NI PXIe platform & custom application with algorithms implemented in LabVIEW, a compact & portable Radar Test & Evaluation System has been materialized.
Description:
Radars are designed to detect aircraft, ships and vehicles at long ranges and also multiple targets. Radar allows the operators to distinguish between friendly and hostile aircraft hundreds of miles away.
Using LabVIEW, LabVIEW FPGA and 1553B Communication at Digilogic System Pvt. Ltd we developed and tested the test system called Radar Test and Evaluation System (RTES), which uses NI Modular Instruments and TES (Target Echo Simulator) to simulate a microwave signal as a Target Reflection for the Radar to detect the target and test the functionalities of the Radar.
Initially RTES takes the carrier signal of Ku-band range from Radar and the reference pulse waveform from Radar. Control words like Target Range, Relative Velocity, Acceleration and Initial Attenuation are given to the Radar through 1553B Communication.
The Doppler Frequencies, two different frequencies at 50MHz±fd and 50MHz are generated from the NI PXI 5641R Analog Output. Doppler Frequency (50MHz±fd) has to be calculated based on the control word Relative Velocity () given to the Radar. Doppler Frequency varies at a range in the Kilo Hertz’s.
Doppler Frequency = Where Relative Velocity t=1mSc (Update period)
By taking the reference pulse waveform from Radar, measure the ‘pulse width’ and ‘pulse repetition frequency’ and Doppler Frequency, calculates the initial Delay using NI PXI 5641R DIO module.
Delay = Range, Where time (t) =1mSc (Update period)
Based on the Delay, Current Attenuation is calculated, and the attenuation values are fed to TES through NI PXI 6704 Analog Output Module. Based on the attenuation the Carrier signal attenuation is given to simulated signal for the Radar.
To generate Doppler Shifted Carrier Signal, this Doppler Frequency (fd) should be added to the Radar carrier signal which is at Ku-band range. So a three stage filter configuration has been used to convert the Doppler Frequency of kHz to selected Ku -band. This carrier signal is fed to antenna as a simulated signal of the target.
The Doppler Frequency, Delay and Relative Velocity has to be calculated based on the current delay, the calculated values has to be written to Radar through 1553 communication. Calculated control word are written to Radar using 1553 Communication and also read from the Radar Continuously.
All control word and current Doppler Frequency, current Relative Velocity and current Delay are calculated regularly based on the update rate (t) until the Current Range becomes zero.
This system has capability to simulate multiple targets simultaneous to test the performance of the Radar.
MIL-STD-1553 Communication SW:
