A high-speed and high-temperature calorimetric solid-state thermal mass flow sensor (TMFS) design was proposed and its sensitivity to temperature and airflow speed were numerically assessed. The sensor operates at 573.15 Kelvin (300 °C), measuring speeds up to 265 m/s, and is customized to be a transducer for an aircraft Air Data System (ADS). The aim was to enhance the system reliability against ice accretion on pitot tubes’ pressure intakes, which causes the system to be inoperative and the aircraft to lose protections that ensure its safe operation. In this paper, the authors assess how the distance between heater and thermal sensors affects the overall TMFS sensitivity and how it can benefit from the inclusion of a thermal barrier between these elements. The results show that, by increasing the distance between the heater and temperature sensors from 0.1 to 0.6 mm, the sensitivity to temperature variation is improved by up to 80%, and that to airspeed variation is improved by up to 100%. In addition, adding a thermal barrier made of Parylene-N improves it even further, by nearly 6 times, for both temperature and air speed variations.

The importance of Time synchronization for distributed applications is growing. The most currently used synchronization protocol is NTP [1]. NTP and GPS satisfy the majority of the world's time synchronization needs, although, GPS have limitations [2]. GPS cannot function inside buildings, or in places where there are physical obstructions and high amounts of electromagnetic noise. In addition, GPS is a costly solution. This work proposes a new approach to synchronize time among machines interconnected by computer networks, which minimizes the disturbance introduced by the network with no extra hardware cost. The methodology employs high-resolution clocks and stochastic methods to minimize the error introduced in time measurement carried out across the network. It also uses an adaptive approach to continuously tune the synchronization mechanism to the network traffic characteristics. An increase of time synchronization accuracy of two orders of magnitude, in comparison with traditional estimation methods was obtained as a result.

This article analyzes the use of Remotely Piloted Aircrafts (RPA) in VOR (Very High Frequency Omnidirectional Range) flight inspection. Initially, tests were performed to check whether the Autopilot Positioning System (APS) met the regulatory requirements. The results of these tests indicated that the APS provided information within the standard regulations. A Hardware in the Loop (HIL) platform was implemented to perform flight tests following the waypoints generated by a mission automation routine. One test was performed without introducing disturbance into the proposed test platform. The other four tests were performed introducing errors in latitude and longitude in the APS into the platform. The errors introduced had the same characteristics as those measured in the initial tests, in order for the simulation tests to be as similar as possible to the real situation. The tests performed with positioning errors only did not lead to false misalignment detection. However, introducing positioning errors and a 4° VOR misalignment error, a misalignment of 3.99° was observed during the flight test. This is a value greater than the maximum one allowed by the regulations, and the system indicates the VOR misalignment. Five flight inspection tests were performed. In addition to the APS errors, tests with a modulation error were also conducted. Introducing a 4° VOR misalignment in conjunction with modulation error, a misalignment of 4.02° was observed, resulting in successful misalignment detection.

With an increasing demand for nanosatellites to perform accurate pointing, such as on Earth observation missions, the availability and accuracy of the orbital position and velocity information on board the satellite’s computer become indispensable, as, for instance, when the determination of the attitude is based on star sensor for an Earth pointing satellite. The conventional way of providing this information is to run an orbit propagator, which is a high-order integrator algorithm such as the Simplified General Perturbations Satellite Orbit Model 4 (SGP4), onboard the satellite, supplied with the position and velocity uploaded from the ground station on a regular basis, e.g., every one or two days, depending on the required orbit accuracy. For a satellite mission with a more stringent requirement, an onboard Global Positioning System (GPS) receiver is desirable to get higher accuracy. Additionally, the GPS receiver can be used for time synchronization in-orbit and for accurate process tag timing. This operation requires a great computational cost and high memory resources. Since most cubesats are limited by the available processing power and usually on-board computers do not use multi-core processing, they suffer long computing times in forced mode. This work presents a new autonomous method to determine satellite position without orbit propagation, GPS, or the necessity of receiving velocity and position from a ground. The proposed system relies on a set of a star Sensor and a horizon Sensor to perform autonomous geocentric attitude and orbit (if desired) determination. A ground device platform composed of two cameras to simulate the star and horizon sensors, together with two portable projectors to depict images of a star field and the Earth limb was created to validate the attitude determination algorithms. An open-source code for detecting the inertial orientation of the star sensor through the astronomical imaging of the sky was employed, whereas the horizon sensor attitude was computed using standard image processing methods. The hardware and software requirements are presented, and their performances are discussed. Results have shown that a significant improvement in attitude knowledge can be achieved with this strategy, even without onboard orbit propagation. In fact, it can be shown that some orbit ephemeris can also be computed by this arrangement as a side effect.

A reliable telemetry link is a key element to reduce reflies and to enhance test flight efficiency (i.e., real-time test point validation) and safety in flight test campaigns. However, the telemetry link undergoes losses owing to radio frequency noise and flight test maneuvers. In addition, the telemetry community has been facing a reduction of the available bandwidth owing to electromagnetic spectrum auctions. Many methods have been presented to solve these problems; however, no conclusive solution has been obtained. In view of these issues and by focusing on flight test requirements, IPEV, an Air Force Flight Test Center, proposed an iPCM Telemetry protocol as a potential solution to vital matters regarding the reliability and bandwidth of telemetry links. This paper presents the iPCM architecture and the ground and flight test results. Test results demonstrated the iPCM's capability to recover corrupted data and ensure data integrity and reliability. In a flight test, 100% of the data was successfully retrieved by iPCM without any noise and loss compared with the 98.24% received by PCM IRIG-106. Similarly, for the ground test results, 100% of the data was retrieved successfully by iPCM, and only 88.45% by PCM. In addition, the iPCM protocol provides an option to dynamically select an FTI parameter list to be transmitted. In a typical test scenario, this feature of frame changing in the parameter list can achieve a 65% reduction in the bandwidth usage in comparison with PCM IRIG-106