Recent News

The spring annual meeting of the American Society of Photogrammetry and Remote Sensing (ASPRS) was held in Louisville Kentucky (It took me a few tries to get the local pronunciation Lewa-vul).  I had  the privilege of enjoying a traditional mint julep while touring the historic Churchill Downs, home of the Kentucky Derby, which is the longest running sporting event in North America.

At the convention, a long standing shortcoming for mapping in North America is finally being addressed.  The ASPRS, after resting on the previous mapping standard for nearly 25 years, is modernising the mapping standards for both Photogrammetric and LIDAR mapping.  The draft standards are nicely modern and do away with the archaic accuracy formula and are replacing it with a fairly simple table of pixel sizes and RMS values which we are all familiar with.

The standard is great because in each simple table they represent standards for different accuracy requirements which would be suitable for projects with different needs, such as engineering, mapping, or say forest resource.  Any geospatial organization could consider simplifying their standards by just indicating (ASPRS Class 1, 2, 3… ). Canadians don’t have to worry, our American Brethren have adopted the metric system!

Adoption often does take time but in the meantime having a simple, flexible, and modern standard, should be a great asset to any organization considering procuring geospatial data.

Check out the draft standards:

http://www.asprs.org/PAD-Division/Map-Accuracy-Standards-Working-Group.html

The precise, high quality aerial imaging provided by Airborne Sensing is combined with the latest advances in geodesy and photogrammetry in all our project designs to ensure that our completed projects meet or exceed client specifications. With over 20 years of experience in airborne GNSS post-processing, we boast complete project planning infrastructure, an in-house professional geodetic surveyor, direct georeferencing with our GNSS/IMU Position Orientation System (POS), automated aerial triangulation processes with manual oversight, geodetic ground survey capacities, and the creation of Digital Surface Models (DSMs) and orthophotos. We maintain scanning equipment to bring analog film products into digital image processing and photogrammetric environments.

Precise Positioning Experience
Over 20 years ago, Airborne Sensing conducted one of the first airborne GPS projects in Canada, which required the development of a camera interface that sends the mid-point of an exposure signal to the GNSS event-mark-file with an accuracy of 300 microseconds (2 cm). Eccentricity parameters between the antenna phase centre and the optical centre were measured with mm accuracy. Even with single frequency GNSS (then called GPS) technology, ASC proved that accuracies of less than 2 decimetres could be achieved with receivers as far as 400 kms away from the survey area.

Complete Project Planning
Airborne Sensing has established procedures for project planning to ensure that all delivered materials are consistent with client specifications, and our surveys are designed according to the use of active networks in the area and static GNSS observations. With Geographic Information Systems (GIS), we design project elements such as flight lines, project areas, airport bases, active GNSS stations, and existing geodetic control. GIS maps form the basis of photo control operations, flight operations design, and real-time project weather analysis. In consultation with the client, we use GIS to design the project with appropriate considerations such as targets and photo identifiable control. We consult with control and spatial referencing agencies (at the municipal, provincial and federal levels) to determine levels of accuracy available, and how these relate to the project specifications and we determine what active GNSS networks exist in the area (e.g. CORS, CACS, other Virtual Reference System (VRS) networks), computing transformations as requried. The geodetic and photogrammetric products are processed with the following programs: Applanix: Direct georeferencing Inpho: Aerial Triangulation observations BINGO: Aerial Triangulation Grafnav: Kinematic GNSS processing from airborne sensor with no IMU input Grafnet: Static GNSS network adjustments from GNSS base stations PPP: Precise Point Positioning to compute GNSS base station coordinates TRNX: Federal transformation software to transform reference frames from year to year NTV2: National datum conversion software Global Mapper/AutoCAD/Google Earth: GIS to develop map overlays.

Professional Photogrammetric and Geodetic Surveys
Our geomatics manager has over 20 years experience as a professional surveyor for engineering, geodetic and photogrammetric surveys of projects small and large, through North America, Latin America and the Caribbean. Trained in Germany, Canada and the U.S. and a registered Geodetic Surveyor with the Association of Ontario Land Surveyors (AOLS).

Direct Geo-Referencing and Aerial Triangulation
The GNSS/IMU Position and Orientation System (POS) used by Airborne Sensing was developed by the Applanix Corporation. The GNSS/IMU POS collects GNSS positioning data during flight at 1Hz or 2Hz, and IMU data at 200Hz. It measures the position of the camera relative to the centre of the earth to less than 10 cm, as well as the angle of the camera relative to the mathematical surface of the earth to slightly more than 1/1,000 of a degree. Output from this device is then post-processed using GNSS/IMU post-processing and filtering algorithms to compute the xyz coordinates and opk orientation of the camera at the time of exposure.

During some recent winter testing Airborne installed a LiDAR and Digital camera in a dual-port Piper Navajo to put Lidar and Photogrammetry to a head-to-head test.  As one of the only companies in North America who has aircraft capable of hosting two large format sensors simultaneously, we decided to see what the LIDAR vs MULTI RAY PHOTOGRAMETRY debate was all about first handed.

Some preliminary observations:  While in vegetated areas  LiDAR appears to render the “bare earth” surface better than photogrammetric Digital Surface Modelling (DSM), on hard surfaces we only see 1.5 pixel RMS difference (at this scale approximately 6 cm), when comparing DSM and LiDAR surfaces. While both surfaces performed with similar accuracy characteristics, the traditionally compiled Photogrammetric product still gives the best representation of the terrain when considering feature such as curbs and high-slope hard surfaces.

Putting aside the bundling up in big winter jackets for the cold flights, it was a great adventure and awesome opportunity to get real data to shed light on the performance of these technologies.

As we are rolling out our new and improved website, we are looking forward to engaging our friends in the geospatial community with multiple channels of information.  In our 34^th year of business, we’ve seen a lot of changes in the way products get delivered to our client and the way their requests get to us, but then as now, the basic tenet has always been:  Our clients deserve the best service that can be offered in this field.  By this we mean on time completion of projects we take on, consistent imagery across the project area, delivery on time so you can get on with your mapping needs, all at a competitive price.

In the weeks ahead, we hope to be announcing even more variety in the technology we are capable of using to serve your needs, but regardless of the vehicle we use to deliver land data, the destination remains the same: YOUR SATISFACTION.