Lecture activities:
1976-1993    Internal education of mathematical assistants, mathematical lectures
1991, 1998:    Internal Lectures on Synthetic Aperture Radar
2004:    Internal Lectures on Moving Target Indication from Airborne Platforms
Since 1992:    Lecture on “Radar signal processing” at the Ruhr Univ. Bo-chum
Since 2005:     Lecture on “Radar techniques” at the Rhineish-Westphalian Technical-University Aachen (RWTH)
Since 2007:    Lecture “Introduction to radar” and “Aerospace radar” at the University of Siegen
Since 2012:    Lecture “Selected topics on radar” at the University of Siegen


Honors and Awards:
1991    Price of the “Informationstechnische Gesellschaft (ITG) in the VDE” (shared with H. Wilden) for the works on the "crow's nest antenna".
2003    Honorary professor at the Ruhr University Bochum
2005    “Radar Prize” of the European Radar Conference (EuRad) Paris, shared with D. Cerutti-Maori, W. Bürger and A. R. Brenner
2007     “GRS-S Transactions Prize Paper Award of the year 2006” together with I. Walterscheid. A. Brenner and O. Loffeld.
2012    “Group Technical Achievement Award of the year 2012 by the Eu-ropean Association for Signal Processing.(EURASIP) -
2012    “Best Paper Award” by the European Association for Signal Processing.(EURASIP) for the journal paper
2014     IEEE-fellow „For contributions to multi-channel synthetic aperture radar and radar array signal processing“.

Past and current working fields:
a)    Nonparametric radar detection for non-Gaussian distributions, development of nonparametric tests for coherent and incoherent pulse trains, derivation of Pitman- and Bahadur efficiencies, simulations with application of the importance sampling technique.
b)    Theory and practice of the crow’s nest antenna (CNA): The CNA which was invented at FHR is a volumetric phased array with statistical distribution of the element positions thought for a 360 degrees radar coverage with-out mechanical rotation. This idea was realized as experimental system by Helmut Wilden and Joachim Ender and investigated with statistical methods in depth and transferred to the German industry.
c)    Development of micro strip components for radar: phase shifters, transmit/receive modules, a 64 x 64 Butler matrix for a multibeam antenna (together with Helmut Wilden) 
d)    ISAR for aircrafts in flight, applied to signals recorded by the ELRA system
e)    SAR imaging algorithms for multi-channel systems: Joachim Ender designed the “Airborne Experimental Radar” (AER) and supervised its building up, developed a command & control and a mission planning & execution software, operated this system in a couple of flight campaigns and investigated various techniques like spotlight SAR with electronically scanned antenna, high-resolution wide-scan mode, azimuth ambiguity suppression, jammer suppression and image generation under jamming conditions, multi-baseline across-track interferometry, along-track interferometry, ground moving target indication via post-Doppler STAP. Joachim Ender designed also the basics of the following-up system PAMIR (Phased Array Multifunctional Imaging Radar) with a 20 % bandwidth phased array antenna, additional modes like sliding mode, scan-MTI and ISAR for ground moving targets, continued and finalized by Andreas Brenner.
f)    Bistatic SAR system aspects and processing: Joachim Ender initiated the experimental investigation of bistatic SAR by operating the two systems AER and PAMIR simultaneously in a Bi-SAR mode. He developed a new algorithm in the frequency domain for the translational invariant geometrical constellation.
g)    Space based MTI systems: Joachim Ender investigated several designs including multistatic radar systems distributed over a cluster of satellites for sensitive GMTI, analyzed the performance in terms of clutter suppression, detection probability and position estimation.
h)    MIMO arrays applied to SAR: Joachim Ender invented the ARTINO principle with a sparse MIMO array distributed along the wings of an unmanned aerial vehicle and investigated different approaches to SAR and MTI via MIMO arrays.
i)    Compressive sensing applied to radar: Compressive sensing (CS) techniques offer a framework for the detection and allocation of sparse signals with a reduced number of samples. Joachim Ender investigated the feasibility of CS based pulse compression, radar imaging, and air space surveillance with array antennas using simulated and real raw data and published the results being the first author from Germany on this field (“Best paper on signal processing” in the year 2012). His current interest is the application of compressive sensing to ISAR autofocusing, MIMO radar systems and sensor data fusion for passive coherent location (PCL).
j)   Co-Investigator of the scientific program “Bistatic exploration” together with the Center for Sensor Systems (ZESS) of the University Siegen