Buying a mobile mapping from 3D Laser Mapping was a great decision – we have an amazing system that suits our needs perfectly and if you ever need any support – you always get an answer to your problem.Alfred Mulder, Project Leader at Geomaat.
StreetMapper Mobile LiDAR system can be mounted on a variety of vehicles for numerous applications making it the ideal solution for fast, accurate and safe surveying in a number of different environments.
Trains and trams
Trucks and 4x4s
Aircraft and helicopters
- Asset Mapping
- Open Field Surveying
- Engineering Planning
- Topographic Mapping
- City Surveying
- Monitoring and Change
- Surface Maintenance
- Tunnel Mapping
- Civil Engineering
- Rail Mapping
- Coastal Mapping
StreetMapperIV is available in 3 different configurations – all of which can be easily upgraded at a later date if and when your needs change. To help you decide which system is for you – have a look at the table below.
Single Pod Configuration
Available in GIS or Survey Grade
With or without Ladybug5 panoramic camera
Dual Pod Configuration
Survey Grade LiDAR System
With or without Ladybug5 panoramic camera
|StreetMapper IV Single GIS Grade||StreetMapperIV Single Survey Grade||StreetMapperIV Dual Survey Grade|
|Main Sensors||Scanner Units||One||One||Two|
|Accuracy||GIS Grade||Survey Grade||Survey Grade|
|Camera Resolution||6 x 5MP||6 x 5MP||6 x 5MP|
|Suggested Software Package||Company:||Orbit||TerraSolid||TerraSolid|
|Scanner Specifications||Points/Second||1 x 1,000,000||1 x 1,000,000||2 x 1,000,000|
|Scan Lines/ Second||250||250||250|
|Point Cloud Noise||3mm||3mm||3mm|
|Suitable for Common Applications||Asset Mapping||X||X||X|
|High Accuracy City Models||X|
|General Information||Scan Pattern||Regular Distributed point cloud||Regular Distributed point cloud||Regular Distributed and crossing point cloud|
|Navigation Capabilities||Requires good GNSS conditions (Open Sky)||Good accuracy even in challenging GNSS conditions (Suitable for Cities)||Good accuracy even in challenging GNSS conditions (Suitable for Cities)|
|Point density @ 60km/h @ 5m range||2000 p/sqm||2000 p/sqm||4000 p/sqm|
- What Speed Can You Capture At?There is no minimum or maximum speed, only the line scan spacing will change which will result in a higher or lower point density.
- Does Accuracy Improve at lower Speeds?Speed does not really affect accuracy. However, the slower you go the denser the pointcloud will be and hence features can be identified and modelled more accurately. Also, accuracy decreases over time when there is no GNSS, so driving faster through a tunnel for example will reduce the amount of time that the system has no GNSS and therefore accuracy will be increased.
- What is the difference between absolute and relative accuracy?Absolute accuracy is the accuracy of a point in relation to its true position. The performance of the GNSS/INS has the biggest influence on absolute accuracy. Relative accuracy is the point to point accuracy and is determined by the performance of the scanner (repeatability and precision). Relative accuracy becomes important when you need to precisely measure the shape or size of objects such as highway rutting or crack measurement.
- What are the advantages of two scanners?Apart from providing double the point density, a two scanner system provides a crossing (diamond) scan pattern which allows for better feature identification (such as the end of highway paint markings) and less shadowing of features (such as the ground behind parked cars and sides of buildings). The single scanner system with rotating mount enables the same benefits of the dual scanner system except that the road will have to be driven twice with different scanner orientations.
- How long can you capture for?Capture time is only limited by the size of the capture storage device. With two 1TB storage drives the system can log laser and image data all day.
- What is the size of a typical dataset?Per hour, the system will log approximately the following: Scanner – 50GB (At maximum measurement rate) Ladybug3 – 42GB (At 3 frames per second) Navigation data – 100MB.
- What is the recommended specification for a processing computer?Our software is optimised for multi-core CPUs and fast hard drives, so we recommend the latest Intel Core i5 or i7 CPUs together with 32GB RAM and either a large SSD hard drive or a RAID0 (striped) hard disk array. A dedicated mid-end graphics card is also recommended but not necessary.
- How long does it take to process the data to a cleaned geo-referenced pointcloud?For a typical highway scan we would suggest allowing 3 days processing for 1 days capture. For urban areas more care must be taken with GNSS processing and cleaning of reflections so allow 5 days.
- Why do we have to initialise and de-initialise the navigation system (INS) for 5 minutes?In basic terms, initialisation is the process of teaching the INS where North is and determining the internal characteristics (bias) of the IMU (because they change with temperature and each time the IMU is turned on). For a good initialisation the system needs good GNSS visibility and fast speed (imagine we are using the geometry of the GNSS positions to determine North). Additionally the system needs some dynamic movement such as turns for the IMUs gyros and accelerometers to “find themselves”. Because the INS data is processed in forwards and reverse we need an initialisation at the beginning and end (also known as de-initialisation).
- What vehicles can the system be installed onto?The StreetMapper IV POD has been designed to fit onto any vehicle that has cross bars or roof rails. However, the system must be installed far enough back on the roof so that the scanner can see over the edge of the vehicle. For power, the system can either use the 12V vehicle battery, or a secondary 12V battery. We can supply additional batteries on request.
- Why is a base station required?Because of atmospheric error and satellite clock errors raw GNSS is generally only accurate to 1 or 2m. To remove these errors a base station is placed over a known point within 20km of the intended scan route. Because the location of the base station is known we can determine what the errors are and apply these error models to the raw GNSS data from StreetMapper IV. This improves the accuracy of the GNSS to up to 1cm.
- Why do you post-process the GNSS and INS data rather than process in real-time?Post-processing the GNSS and INS data during post-processing has two major advantages. The first is that we have full control over the processing and can optimise the solution. The second reason, which is the most important reason, is that post-processing allows us to process in the forwards direction and the backwards direction and then combine and smooth the two solutions together. This is very important since the INS accuracy drifts exponentially over time when there is no GNSS, so processing in both directions reduces the error significantly.
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