Due to Auction 97 frequency sell off and anticipated higher usage of C-Band, space time code (STC) and low-density parity-check (LDPC) code were evaluated for latency, characterization, and performance during flight. The benefit of an STC path can be observed by measuring the channel power of a dual antenna and comparing it to the contributions from each antenna independently. The STC provides a benefit only when both antennas are visible to a receiver and when the combined result of a dual antenna system would destructively add. The Eglin Spectrum Reallocation Fund (SRF) Project transitions the United States Air Force (USAF) aeronautical mobile telemetry (AMT) from operations in frequencies auctioned by the Department of Commerce (DOC) as part of Auction 97. This paper describes the AMT test methods used and upgrades accomplished by the 96th Test Wing in order to meet requirements of Auction 97.

In this paper, an algorithm for distance aware energy efficient Base Stations (BSs) is proposed, which exploits the knowledge of the distance between the Mobile User (MUs) and the BS. The proposed algorithm changes the cell radius depending on user distribution in the cell. In this case adaptive (dynamically changing) concentric circles are virtually drawn so that the UEs in the same concentric circle can get constant power from the BS. It means that the mobile users(MUs) are clustered based on the distance from the BS. The energy consumption has been evaluated without sacrificing significant offered Quality of Service (QoS) on the cellular networks. The proposed scheme aids to achieve energy saving as a result of reduced transmit power based on reducing the radius of the concentric. As the radius reduces the transmit power is also reduced logarithmically. The system uses Omni directional antenna which covers all 360 degree of the cell at once. The simulation result shows that as the distance from the BS decreases, the transmission power decreases and the energy also decreases. The distance or the radius variation dynamically is based on the number of users in that track comparing to the minimum required number of threshold users. The result shows that an average of 0.1762 dB or 1.04 Watt which is 9.45% of the maximum transmit power can be saved by dynamically varying the base station the radius at the area of low traffic load for a single scan.

Cellular based Range Telemetry provides a lot of benefits over legacy Aeronautical Mobile Telemetry, such as: • Higher capacity, allowing multiple test articles (i.e. telemetry radio links) which have active telemetry data measurements exchanged in near real time. • Bi-directional radio links, that can allow new signaling with the avionics equipment on the test articles. • Higher performance provided by spectrally efficient OFDMA waveform used in LTE and the dynamic link adaptation that is built into the LTE waveform. With the CRTM cellular approach, the overall range coverage area is broken into multiple coverage areas, each served by a single cell. To maintain seamless service throughout the test flight, CRTM must support seamless mobility as the aircraft moves between the coverage areas of these cells. This is achieved using the connected mode handover procedures supported by LTE technology. Traditional LTE networks rely on signal strength measurements made by the User Equipment (UE) to make handover decisions. The measurement system and handover procedures have been designed to support mobility at speeds under 500 km/hr. To support mobility at higher speeds, the following need to be taken into account: - LTE User Equipment (UE) RF Signal Measurements: Accuracy of measurements depends on UE’s capability to measure the signal strength of a neighbor cell while synchronized to its serving cell. The higher Doppler shifts expected in an AMT environment due to the higher test article speeds and the higher frequency of operation along with the difference in Doppler shifts between the serving cell and neighbor cells complicates cell measurements. - Handover Processing Time: The serving eNodeB needs to process the measurements from the UE and initiate handover in a timely manner. Delays in handover processing can result in radio link failures. The higher speeds of test articles in the AMT environment reduces the time available to the eNodeB for handover processing. This paper explains the handover procedure in 4G LTE, with the focus on: Measurement reports that support handover decisions Decisions impacting data service delays during handover impacts to the handover processing when the UE (i.e. test article in CRTM) is moving at very high speed.

The objective of this paper is to describe the tools that have been developed to ease the Flight Test Engineers (FTE) the execution of Flight Test and ensure the highest quality of the final product. This first product is mainly devoted to Production Flight Test (PATM), where the profile and the tests to be performed are almost the same for all flights. As during the PATM there are many checks to do and many data to gather, the idea was to execute in an automatic way as many test points as could be possible. To cope with this requirement we have to develop an Automatic Flight Phase Detection in order to start some applications in the FTE Computer without any human intervention. So, we need a smart assistant to predict the following test points that will be executed. In addition of the previous point, it was also needed to send the results of the data gathering and calculation to a “Digital Flight Test Card” to avoid the use of paper. With both aids, Automatic Flight Phase Detection and Digital Flight Test Card, the efficiency of the execution of tests has been highly improved.

Advances in planning and controls algorithms for Unmanned Autonomous Vehicles (UAVs) have led to a substantial increase in a wide variety of applications. An important task for UAVs is au-tomated high-precision homing-and-docking. This requires the UAV to autonomously estimate its relative bearing to the home docking station and plan its optimal approach accordingly. This paper presents the design of homing and navigation system for UAVs that can operate in near-field scenarios. The system incorporates a dual-transmitter/receiver design and through a modified angle of arrival and motion estimation routine, the UAV can determine its relative bearing to the homing station while simultaneously planning the optimal approach. The approach planning algorithm will be described, along with theoretical analysis and simulated results documenting its performance in comparison to other techniques.

The growth of network and distributed technologies in flight test instrumentation (FTI) has provided the benefits of flexibility, scalability, and compatibility with prevalent computing capabilities. However, to achieve these capabilities, the complexity of each piece of FTI and the overall system has increased dramatically. Even with systems composed of equipment from a single vendor, it is important to have management systems that provide the flexibility to adapt quickly to various system configurations and present unified information to the flight test users. The growth of network technologies and then standardized approaches such as iNET standards becoming accepted IRIG 106 standards is leading to the growth of multi-vendor systems. These multi-vendor systems further increase the need for rapidly reconfigurable management systems. This paper describes a constraints engine we have developed to enable flexible system management systems and reflects on how these techniques have been used successfully in the iNET System Manager.

This paper presents the performance of capacity-approaching low-density parity check (LDPC) coded amplitude phase shift keying (APSK) over aeronautical telemetry channels. We show the bit-error rate results for code-rates of 1/2, 2/3, 3/4, and 4/5 with 16 and 32 point constellations. Results are presented and compared between an optimal and sub-optimal reduced-complexity demodulating system. We also compare the results with SOQPSK-TG under similar channel conditions and provide an estimate of backoff needed for implemention with power amplifiers.

In previous work, we presented a link quality metric for adaptive modulation and coding of two standard telemetry waveforms, orthogonal frequency-division multiplexing (OFDM) and shaped-offset quadrature phase shift keying (SOQPSK). That metric unified error vector magnitude (EVM) and Godard dispersion, for OFDM and SOQPSK, respectively, in the contexts of additive white Gaussian noise (AWGN) channels. In this paper, we present an alternative metric based on low density parity check (LDPC) decoding iterations. We show this new metric to be an equally effective substitute for AWGN channels but also to be applicable to a wider variety of channels, including those with multipath and interference. Furthermore, we show the metric to be robust within sub-optimal, lower complexity receiver architectures.

This paper summarizes the design of a discrete-time quadrature downconversion and resampling processor that operates on samples of a 70 MHz IF signal. The unique properties of discrete-time processing—aliasing due to resampling bandpass signals and polyphase filter decompositions—are applied to create a low-complexity approach that does not require any arithmetic operations at the IF sample rate. The required tasks are performed in two stages: a downsample-by-2 operation followed by a more traditional resampler based on a polyphase filterbank.

This paper investigates the application of 16-APSK modulation to aeronautical mobile telemetry. The peak-to-average power ratio vs. code rate tradeoff is mapped to an optimization problem involving spectral efficiency and the constellation parameters. The optimization results produce a theoretically optimum solution that is 3.95 times more spectrally efficient as uncoded SOQPSK-TG. When implementation losses and the available IRIG 106 LDPC code rates are factored in, the advantage drops to 3.20 times the spectral efficiency of SOQPSK-TG.