Hermeus

Last summer, I interned with Hermeus in Atlanta, GA, as an Avionics Engineering Intern on Mk2, a supersonic aircraft. Over the course of the internship, I led four main projects: developing a low-power MIL-STD-704 test rack for power simulation, testing an LVDT simulator module and conducting environmental testing, performing GPS antenna tests, and building DC-DC converters. I also supported thermal testing for the RF tray and conducted post-thermal functional tests. 

Through this work, I gained hands-on experience with programmable lab equipment, SCPI/PyVISA, Linux, Ethernet, PCIe, and SSH, PCB design, and assembly. I also supported multiple environmental tests, from vibration to thermal, on avionics and RF systems.

Project 1 - MIL-STD-704F Power Simulation

For this project, I worked on building a MIL-STD-704 test rack to simulate aircraft electrical power conditions. MIL-STD-704 is a U.S. military standard that establishes the electrical power characteristics for aircraft systems, defining normal and abnormal power conditions to ensure compatibility and reliability for onboard equipment. The standard specifies requirements for voltage, frequency, phase, ripple, and abnormal conditions such as overvoltage and undervoltage, ensuring that onboard equipment performs reliably even during power fluctuations and other abnormal conditions encountered in flight.

At the start, I had no experience working with programmable power supplies, SCPI or PyVISA. I began by learning the basics of SCPI and wrote simple Python scripts that communicated with a digital multimeter, measuring the output voltage from the power supply. I also wrote a Python script to generate a simple binary waveform on the Waveform Generator to familiarize myself with programmable lab equipment. In this process, I became familiar with Ethernet, USB communication with lab equipment. 

Once I was comfortable, I developed 8+ Python scripts using SCPI and PYVISA to automate MIL-STD-704 compliance tests, verifying avionics hardware tolerance to brownouts and voltage drops while streaming time-series data to Nominal. 

I then built a low-voltage MIL-STD-704 test rack with programmable power supply, oscilloscope, and configured a Raspberry Pi (PoE) with SSH access to remotely simulate aircraft power conditions (spikes, ripple, and undervoltage). The ultimate goal is to provide a universal test rack for all hardware then can run on their own without the need of laptop or close supervision. 

Through this project, I gained hands-on experience with Linux, GitHub, and full-system integration, as well as the end-to-end process of hardware testing and automation.

Project 2 - LVDT

In this project, I worked on simulating and testing an LVDT (Linear Variable Differential Transformer) module used to control actuators on aircraft. 

To verify module functionality, I performed Hardware-in-the-Loop (HIL) testing for LVDT modules by simulating sensor signals with a PXIe chassis and displaying real-time waveforms on an oscilloscope. To connect the simulator to a laptop for internal excitation, I also assembled a custom DB-to-Ethernet breakout board. and created wiring harness documentation to support system integration.

Once the simulation setup was complete, I created wiring harnesses and integrated a full environmental test system with a military-grade Remote Interface Unit (RIU). I then developed Python scripts to automate thermal and vibration testing, enabling reliable verification of the LVDT’s performance under extreme conditions. Through this project, I gained hands-on experience with PXIe/PCIe systems, environmental testing, and system-level test planning.

Project 3 - Antenna Testing

In this project, I tested the performance of GPS flight antennas with different LNAs (filtered vs. unfiltered) by evaluating Carrier-to-Noise ratio (C/N₀) and Dilution of Precision (DOP). I began by designing and building wiring harnesses for the antenna test setups to collect raw GPS data from the INS and NovAtel systems. Next, I developed Python scripts to process the data: converting GPS time, filtering, and streaming time-series data to Nominal for visualization and direct performance comparison. Finally, I documented my methods and findings in a slide deck, clearly outlining the data processing steps and performance results.

Project 4 - DC-DC Converter

In this project, I get to learn how to design PCB using Altium Designer, from drawing a schematic to routing board, doing design rule check, and generating BOM and Gerber file. I designed a DC-DC converter for RF system on Altium Designer with common noise rejection and reverse polarity protection.