PATNA: RITES Ltd had floated a tender for a Drone Survey for the Topographic and Hydrographic Cross Section Survey using Photogrammetric Technique by Unmanned aerial vehicle (UAV)/Drone equipped with DGNSS or similar arrangement with LiDAR technology in connection with the Hydrographic study of a proposed new single 70 Km BG line from Khagaria (Sonpur Division of East Central Railway) to Kusheshwar Asthan (of Samasthipur Divison of East Central Railway) in Bihar.
The work is estimated to cost ₹. 1,19,51,000/- (Rupees One Crore nineteen lakhs fifty-one thousand only). This Estimate, however, is given merely as a rough guide.
Khagaria is a city in Indian state of Bihar and the administrative headquarters of Khagaria district. Khagaria is a part of Munger division. It is located at 25.5°N 86.48°E and has an average elevation of 36 metres (118 feet). Khagaria is well connected with other parts of country by roads and trains. Khagaria can easily be reached from many major cities of India by road via National Highway 31. Khagaria is well connected to many major cities of India by Indian railways. The nearest airport is in Patna. Railways are constructing a 40 km railway line connecting Khagaria to Kusheshwarasthan via Alauli. Railways have assigned RITES to undertake hydraulic / model studies of this rail alignment falling under flood plains of Kosi river, Kamla balan and Kareh between Alauli and Kusheshwarasthan.
In this regard, RITES proposes to conduct Topographic & Hydrographic survey to develop plan & cross sections showing the latest river courses, streams, nalas and any other water bodies showing details of latest position of channels/dykes and other permanent features like bridges, roads, highways, habitation, marginal bunds, vegetation etc in aerial stretch of approx. 28 km along the planned play zone of river Kosi and aerial stretch of approx. 11 km along the planned play zone of river Kareh using Photogrammetric technique by un-manned aerial vehicle (UAV) / Drone equipped with DGNSS or similar arrangement with LIDAR for surveying ground features and Hydrographic survey for water bodies as per technical specifications laid down in the Tender published by RITES.
The scope of work to be performed by the agency under the present tender is:
Master control point (MCP)
MCP survey using DGPS (for horizontal control) and Auto Level (for vertical control) shall be carried out to establish horizontal and vertical accuracy of +5cm or better. The control point locations should be selected so as to be:
- Clear of HT/LT lines
- Free from multi path problems associated with tall features in the vicinity
- Free from foliage
- Open to sky with a clear view of the horizon
- Control points may be located on permanent features such as rock outcrop, bridge abutments, culvert etc. If such features are not available, RCC pillars with nail at centre (Mix 1:2:4, at least four 6mm bars at corners with suitable stirrups) 15cm x 15cm x 60cm, 45cm embedded in ground with CC M10 (5cm wide all around), shall be erected in advance for this purpose. The pillar, with proper indexing & labelling, shall be painted yellow and duly marked for identification with black paint.
- Permanent control point(s) may be fixed for both horizontal and vertical control at the start of work. Horizontal control may be fixed with long hour (12 Hours) GPS continuous observation. For vertical control the agency will carry the level of existing bench marks to the control points using Auto Level/Digital Level with requisite accuracy. Benchmarks for transfer of level shall be provided to the agency.
- Agency shall plan closed loops consisting of a network of triangles, connecting these master control points. The control points shall be adequately spaced with the triangles, formed, preferably not too acute nor obtuse covering the survey area uniformly. The agency shall get the network of master control points finalised in consultation with RITES before DGPS observations.
- Sufficient observations (minimum 2 hours) with DGPS should be done for common period on these point locations using at least five receivers forming five vertices of network triangles. The sets used shall be dual frequency having differential post processed accuracy of at least ± (5mm, +1 ppm length).
- The Surveyor shall download the raw GPS data on a computer at site itself and thereafter apply suitable projection system so as to arrive at grid coordinates (Northing, Easting and Elevation with reference to Mean Sea Level) from geographical coordinates (Latitude, Longitude & Ellipsoidal Height) observed at site. Each day’s work shall be compiled and mapped/documented the same day to be provided to RITES. Baseline check shall be done for every day’s work to ensure accuracy.
- For vertical control the agency will carry the level of existing bench marks to the control points using Auto Level/Digital Level. Auto level/Digital level must be duly calibrated from the manufacturer or his authorized agent before use on the project. The date of calibration certificate shall not be earlier than 03 months from the date of start of work. Contractor shall close levelling work on daily basis and find out closing error. Closing would mean that levelling work shall be started from a known point (first point) and closed at a known point (or the first point where known points are not available) with an accuracy of 12√K mm, where K is the circuit length in km.
- Recorded data of above observations shall be downloaded and processed through software application to establish prime traverse as a whole.
- In addition to the above master control points, adequate network of secondary control points shall be established, if required, to achieve the stipulated accuracy levels for work.
- All teams shall ensure that details in required format are furnished promptly to RITES representative working at the site, in softcopy and hardcopy forms, duly checked and verified, supported with “not to scale” neat sketches.
- Both, the Raw Data (in RINEX as well as proprietary formats of GPS manufacturer) as well as the Transformed Data shall be supplied by the Agency to RITES.
- After submission of list of final control points with values, RITES engineer would carry out a RANDOM CHECK of few control points in the field, as decided by the Engineer. The contractor has to provide all required manpower, equipment, vehicle and other logistical arrangement for this field check. Cost of this checking is included in the rates quoted and no extra payment will be made on this account. This checking can be done in patches also.
- On account of any inaccuracy beyond specified tolerable limits found at this stage, the agency shall be liable to repeat the work at their own cost.
- Final list of all control points, bench marks and reference points with Co-ordinate (X, Y, Z in UTM system) with their location with respect to existing roads/identifiable permanent features for easy identification have to be prepared and submitted to RITES along with Photographs of each master control point pillar after finalizing writing etc. in digital form with proper indexing and labeling. The photographs shall indicate the pillars/points and its surrounding areas clearly. Master Control points establishment report, after completion of above activities, shall be submitted to RITES duly stating the accuracy of work achieved.
- A minimum of 25 check points adequately spaced & uniformly distributed in the survey area should be established.
- The check points shall be identified & duly marked on ground on identifiable permanent features or using as specified RCC pillars, in consultation with RITES engineer, before the commencement of picking up of ground data. The check points should be strictly different
- from any geo-referencing or control network points. The check points shall be measured using similar methodology for establishment of MCPs.
- The coordinate values of check points thus obtained shall be compiled, mapped & documented on the same day to be submitted to RITES. Final list of all control points, bench marks and reference points with Co-ordinate (X, Y, Z in UTM system) with their location with respect to existing roads/identifiable permanent features for easy identification have to be prepared and submitted to RITES along with Photographs of each check point pillar after finalizing writing etc. in digital form with proper indexing and labeling. The photographs shall indicate the pillars/points and its surrounding areas clearly. Check Point Establishment report, after completion of above activities, shall be submitted to RITES duly stating the accuracy of work achieved.
- The Master Control Points & check points established by the agency shall be protected by the agency till the completion of the Consultancy Services.
- A tentative network of master control points and check points covering the survey area is attached at the end of this section, for illustration purpose only, as Fig. 1. The agency shall suitably plan the network to meet the specified accuracy for this work.
Topographic and Hydrographic survey
- The activity involves carrying out Detailed Topographic & Hydrographic Survey to capture the essential ground feature covering the latest planform of river courses, streams, nalas and any other water bodies showing details of latest position of channels/dykes and other permanent features like bridges, roads, highways, habitation, marginal bunds, vegetation etc in stretch of approx. 28 km along the planned play zone of river Kosi and stretch of approx. 11 km along the planned play zone of river Kareh (Refer Section 6 Drawing for survey extent). The survey data shall primarily be represented in the form of Topographic plan, river khadir cross sections showing bed profile and DTM of the survey area.
- The interval of the cross section shall be 300m along the river reach covering the identified extents. A total of 130 nos of cross sections across river khadir having cumulative length of 1250 km has been estimated. The bed levels shall be shown at an interval of not more than 10m in water bodies and 50 m in the remaining section and depicting reduced level with respect to available Bench Mark (BM) to capture the essential ground features along the cross section. The natural and man-made features shall also be surveyed and plotted to reflect the existing features in the survey area with chainages marked starting from left high bank to the right high bank. Any temporary or permanent protection works to be accurately covered and detailed in topographic plan & cross sections. The data on nature of terrain viz. sandy, vegetation, dense vegetation, marshy, grassy, water channels, village boundary, habitation, roads and prominent bridge structures like wells, abutments etc. shall also be covered along with the chainages of change points along the cross section & topographic plan. The sub-consultant shall proceed the work from one end & progress towards the other extent for completion.
- The following accuracy level shall be adopted.
- Horizontal accuracy of +10.0 cm or better;
- Vertical accuracy of +20.0 cm or better;
- Photogrammetric technique by un-manned aerial vehicle (UAV) / Drone equipped with DGNSS or similar arrangement with LIDAR, which can meet the specified accuracy levels shall be employed for surveying ground features.
Planning of flight operations
- The contractor is responsible to obtain necessary clearances as per the latest guidelines from Director General of Civil Aviation, Ministry of Defence, Government of India, and other agencies as may be required to complete the job of flying over the AoI, digital camera data etc. The client would provide necessary documentation; however, getting clearance would be the entirely the responsibility of the contractor
- The flight path shall cover the study area completely including enough cross flight lines to eliminate shadowing and allow for proper quality control. Flight line overlap should be 30% or greater, as required, to ensure that there are no data gaps between the usable portions of the swaths. Data collections in high relief terrain should have greater overlap. Any data with gaps between the geometrically usable portions of the swaths will be rejected. The contractor shall generally avoid missions during inclement weather which have been known to degrade the accuracy of laser return data. The contractor must document mission date, time, flight altitude, airspeed, scan angle, scan rate, laser pulse rates, and other information deemed pertinent.
- All flight trajectories used for the capture of the delivered LiDAR and photograph data will be supplied in KMZ/CAD files. The KMZ/CAD file tables must include the date of capture, local start time, local end time and which reference station was used for each trajectory. The KMZ/CAD file will show photo footprint and its centre.
- Hydrographic survey using Echo-sounder and licensed hydrographic survey softwares like HYPACK for developing under water bed profile in river channels & other water bodies shall be conducted. The hydrographic setup comprising of positioning system and echo-sounder should be of latest specification so as to meet the specified accuracy levels.
- In shadow areas such as dense foliage, shallow ponds etc, where Photogrammetric technique or LIDAR cannot survey accurately, conventional methods of Total Station/ Auto Level/DGPS shall be used to complete the work.
- The data from the topographic surveys shall be available/provided in UTM Co-ordinates (x, y, z) format for preparation of digital terrain model (DTM). All Elevations shall be with reference to Mean Sea Level. The agency would be fully responsible for any inaccuracy in surveys and shall rectify the same at their own cost.
Data Processing & Validation
- The agency shall use latest licensed softwares and qualified personnel for processing of field data. The agency shall provide full support and access to customized or proprietary software or instruments in case of any requirement of the same.
- A close liaison shall be maintained by Survey Engineer / CAD Engineer of Agency with RITES during the period of data processing and be present at RITES Gurgaon office, when required, for clarifications, if any.
- To establish accuracy, the coordinates of check points established during control survey shall be compared with their coordinates obtained after data processing. The validation results shall be documented and submitted to RITES. RITES, if required, may check any other point/features on field for validation of work. The agency has to provide all required manpower, equipment, vehicle and other logistical arrangement for this field check. Cost of this checking is included in the rates quoted and no extra payment will be made on this account.
- Data processing, as above, shall be carried out in parallel with the field activities and processed data shall be submitted to RITES progressively as per payment terms so as to ascertain quality of work and timely resolution of errors.