Papers by Ismael Colomina
This paper addresses the evolution of sensor orientation and calibration over the past forty year... more This paper addresses the evolution of sensor orientation and calibration over the past forty years with emphasis on their applications to the acquisition of primary data for further mapping and geoinformation generation. The paper identifies some limitations of the current assumptions and illustrates how to overcome them with an example and several ideas that the author and his colleagues at the Institute of Geomatics have developed and published recently. The current performance of direct and integrated sensor orientation is briefly discussed as well as the evolution of the Global Positioning System and Galileo and their impact.
This paper describes an alternative to numerically integrate the differential equations of a stra... more This paper describes an alternative to numerically integrate the differential equations of a strapdown inertial navigation system (INS). The use of predictor-corrector multistep methods with variable step-size is discussed and a fourth-order method of the said type is derived.
INS/GNSS integration is a well known technique in navigation and, in general, in time-Position-Ve... more INS/GNSS integration is a well known technique in navigation and, in general, in time-Position-Velocity-Attitude (tPVA) trajectory determination. It is also known, that INS and GNSS are complementary and that the key to their integration is the correct calibration of the Inertial Measurement Unit (IMU) sensors, of the IMU's Inertial Sensor Assembly (ISA) system parameters (axes misalignments and center of navigation),
Since 1999 the Institute of Geomatics has been involved in research and experimental advanced dev... more Since 1999 the Institute of Geomatics has been involved in research and experimental advanced development in the area of integrated inertial/GPS kinematic positioning, attitude determination and gravity measurement. In this paper, a general description of the related hardware and software systems developed by the Institute is given. The systems deal with inertial/GPS data acquisition and processing. The paper discusses, as
The Institute of Geomatics (IG) operates the experimental hardware TAG (Trajectory, Attitude and ... more The Institute of Geomatics (IG) operates the experimental hardware TAG (Trajectory, Attitude and Gravimetry) for GNSS/IMU data acquisition, developed during several projects in the field of inertial navigation in photogrammetry and remote sensing, sensor orientation and geodesy. The hardware basically consists of commercially available devices. The IG has a set of inertial measurement units (IMU) available that cover the whole range of the quality and price spectrum, in order to be able to give answer to the wide demand in the field of inertial navigation research and development. The software is the result of IG development work and ensures time synchronization of the measurements obtained, data capturing for post-processing and operation in real-time mode.
The ATENEA (Advanced Techniques for Navigation Receivers and Applications) project aims to join d... more The ATENEA (Advanced Techniques for Navigation Receivers and Applications) project aims to join deeply integrated GNSS/INS receiver architectures and LIDAR techniques to provide an advanced navigation solution. The approach is suitable for a wide range of surveying applications in difficult environments, being Urban Mapping selected as reference case. ATENEA tackles the most challenging issues of this type of applications, showing how the use of Galileo signals, integrated positioning and observable processing can in one shot solve the more severe technical issues (robustness and continuity), increase accuracy and drastically reduce the system cost. The goal of the ATENEA project is to develop an advanced technology concept for seamless navigation at the cm-level regardless of the environment.
... GRAVIMETRIA GEOIDE Conques sedimentàries Riscos sísmics Navegació Inercial Òrbites Geodinàmic... more ... GRAVIMETRIA GEOIDE Conques sedimentàries Riscos sísmics Navegació Inercial Òrbites Geodinàmica Unificació dels sistemes d'altitud Prospecció minera Estudis geològics regionals Anivellament GNSS Oceanografia Resolució espacial (km) ...
This paper presents a universal approach to geometric modelling in photogrammetry and remote sens... more This paper presents a universal approach to geometric modelling in photogrammetry and remote sensing and introduces the development of a support tool for image exploitation tasks based on this approach.
GP-IMU-Bench experiment consists of simultaneous acquisition of data from multiple inertial units... more GP-IMU-Bench experiment consists of simultaneous acquisition of data from multiple inertial units under the same dynamic and static conditions. To accomplish those conditions, all the sensors are fixed on a platform that is directly mounted into an airplane. This configuration permits all the inertial units to be able to sense the same movements. The aim of this experiment is to obtain a set of data that allows establishing some comparisons among the IMUs that the IG owns. The results of this experiment are very helpful to evaluate which is the best kind of IMU to be mounted on any remote sensor. In order to get these datasets, a series of HW and SW modifications were applied on IG's TAG system for acquiring the data from the IMUs simultaneously. Therefore, this paper goes through these modifications made on the system with a more detailed description of the experiment. Some preliminary results of the comparison are shown.
Measurement Science & Technology, 2010
This research studies the reduction and the estimation of the noise level within a redundant conf... more This research studies the reduction and the estimation of the noise level within a redundant configuration of low-cost (MEMS-type) inertial measurement units (IMUs). Firstly, independent observations between units and sensors are assumed and the theoretical decrease in the system noise level is analyzed in an experiment with four MEMS-IMU triads. Then, more complex scenarios are presented in which the noise level can vary in time and for each sensor. A statistical method employed for studying the volatility of financial markets (GARCH) is adapted and tested for the usage with inertial data. This paper demonstrates experimentally and through simulations the benefit of direct noise estimation in redundant IMU setups.
Current mobile primary data acquisition systems can be grouped in three main categories: terrestr... more Current mobile primary data acquisition systems can be grouped in three main categories: terrestrial, manned airborne and satellite borne. This paper discusses whether Unmanned Aircraft Systems (UASs) together with the appropriate sensing and navigationorientation payloads can constitute a new, fourth data acquisition paradigm of the high-resolution and low-cost type. For this purpose, and based on practical experience gained at the Institute of Geomatics (IG), some fundamental issues of UAS-based photogrammetry and remote sensing (PRS) are reviewed; from the geomatic aspects of navigation and orientation, to the manifold of already existing applications and to various regulatory initiatives that the main aviation authorities are conducting. The paper identifies technical challenges and advantages specific to UAS-based PRS and concludes that, beyond the technical aspects, one key issue is the integration of UAS in the civilian non-segregated airspace.
Strapdown inertial airborne gravimetry as a practical and feasible tool for local and regional ge... more Strapdown inertial airborne gravimetry as a practical and feasible tool for local and regional geoid determination is under research at the Institute of Geomatics (IG). Within the framework of the Spanish-Bolivian cooperation project TERRA, between the Instituto Geográfico Militar of Bolivia (IGM) and the IG, a feasibility analysis on geoid determination in Bolivia by means of INS/GNSS integration is being carried out. TERRA includes, among other goals, the specification of the geoid model that best fits the needs of Bolivia from a global point of view. Simulations in the spatial and spectral domain for GNSS and INS data will allow for an assessment of the performance of the technology. In addition, an empirical covariance model of the gravity anomalies has been derived from CHAMP-data, so that realistic simulations will be carried out. The contribution of other new satellite gravity missions, such as —GOCE—, will be evaluated as well. Actual gravity data will be obtained from a test flight over various topographic conditions to analyze the system response to a highly variable gravity signal. The data will be also processed to empirically verify the simulation results. The aim of this paper is to introduce the project and present some preliminary results.
A redundant inertial measurement unit (IMU) is an inertial sensing device composed by more than t... more A redundant inertial measurement unit (IMU) is an inertial sensing device composed by more than three accelerometers and three gyroscopes. This paper analyses the performance of redundant IMUs and their potential benefits and applications in airborne remote sensing and photogrammetry. The theory of redundant IMUs is presented through two different algorithmic approaches. The first approach is to combine the inertial observations, in the observation space, to generate a "synthetic" non-redundant IMU. The second approach modifies the INS mechanization equations so that they directly account for the observational redundancy. The paper ends with an empirical assesment of the concept. For this purpose, redundant IMU data was generated by combining two IMUs in a non-orthogonal configuration and flying them. Preliminary results of this flight are presented.
The extraction of gravity anomalies from airborne strapdown INS gravimetry has been mainly based ... more The extraction of gravity anomalies from airborne strapdown INS gravimetry has been mainly based on state-space approach (SSA), which has many advantages but displays a serious disadvantage, namely, its very limited capacity to handle space correlations (like the rigorous treatment of cross-over points). This paper examines an alternative through the well known geodetic approach, where the INS differential mechanization equations are interpreted as a least-squares network parameter estimation problem. The authors believe that the above approach has some potential advantages that are worth exploring. Mainly, that modelling of the Earth gravity field can be more rigorous than with SSA and that external observation equations can be better exploited.
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Papers by Ismael Colomina