MWE Presentation on navigation system.pptx

Microwave engineering navigation system overview

1. NAVIGATION SYSTEMS 10.11.22

2. About Navigation System https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf Navigation System is defined as a system providing useful information to determine the position of a boat, a car or an airplane, etc. As there are different ways to describe location, there are also different ways to navigate places.: Celestial Navigation: Celestial navigation is the art and science of navigating by the stars, sun, moon, and planets. GPS (global positioning system): GPS is a satellite based navigation system which allows ground users to determine their exact location, velocity, and time 24 hours a day, in all weather conditions, all over the world. Orienteering: Orienteering is finding your way through a defined course with checkpoints, using only a map and compass.

3. Types of Navigation System: https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf Radio Navigation : It uses radio waves to determine position by either radio direction finding systems or hyperbolic systems. Radar Navigation : It uses radar to determine the distance from or bearing of objects whose position is known. This process is separate from radar's use as a collision avoidance system. Satellite Navigation : It uses a Global Navigation Satellite System (GNSS) to determine position.

4. Landing Systems: https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf Instrument Landing System : The oldest and still most precise form of instrument approach is the ILS. It involves a glideslope antenna, transmitting a signal giving the aircraft vertical guidance, and a localizer, giving lateral guidance. By following these signals, aircraft can descend to almost the runway threshold before gaining visual sight of the field for landing. Microwave Landing System : The Microwave Landing System (MLS) provides precision navigation guidance for exact alignment and descent of aircraft on approach to a runway. It provides azimuth, elevation, and distance.

5. There was a need for a system that improved upon the ILS. The system required can be defined as follow: Reduction in the sensitive area i.e. the area near the antenna responsible for beam interference Enhancement of the region of coverage so that guidance can be provided along curved paths and in three dimensions. Aircraft can then control their own separations and landing procedure in accordance with routine stipulation. Provision for the receiver for course selection in the aircraft by the pilot. This means that wider coverage is not used merely as a gathering zone for the aircraft to finally settle on a single predetermined path, but that almost any path, straight or curved within the sector can be defined by the pilot as his desired approach path. Such paths may be selected depending on what is considered best for the current situation based on factors such as forward speed, rate of descent, angle of attack etc. Development of Microwave Landing System P. Mahapatra, N. Balakrishnan - Microwave landing system - A favourite alternative to current ILS - IETE Technical Review, Vol. 2, No. 11, 1985

6. The MLS is based on the principle of converting the two angular positions of the receiver into a time difference between two different pulses. It uses two narrow beams which are scanned in an oscillatory manner in the azimuth and elevation sectors. At every position within the scan sector the aircraft will receive two pulses from each beam corresponding to the to and fro scans. The aircraft derives its position within the coverage volume by measuring the time difference between these pulses pairwise. The azimuth scan uses a fan beam broad in the vertical plane and narrow in the horizontal plane. Similarly the elevation beam scans up and down using a fan beam broad in horizontal plane and narrow in the vertical plane. Each beam scans it assigned sector at constant sweep rate. There is a finite dwell time or beam pause at the end of each stroke. Principle of Operation P. Mahapatra, N. Balakrishnan - Microwave landing system - A favourite alternative to current ILS - IETE Technical Review, Vol. 2, No. 11, 1985

7. Principle of Operation P. Mahapatra, N. Balakrishnan - Microwave landing system - A favourite alternative to current ILS - IETE Technical Review, Vol. 2, No. 11, 1985

8. Principle of Operation https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

9. Approach Azimuth Equipement: This equipment is installed on an extension of the centre line of the runway For generating oscillating fan beams in elevation and azimuth, several schemes have been considered. It consists of a transmitter, an electronically scanning linear phased array, a control unit and a monitoring system. By suitable switching of the phase shifters, it is possible to scan the beam at constant angular speeds in either direction. The radiating elements are slotted waveguides. The beam has a fixed pattern along its wider direction which is vertical. Since this can be achieved with a fixed phased array, a vertical array of slot radiators fits well. It is important to minimise the reflection of RF energy off the ground in front of the antenna; hence the individual slot phases are adjusted so that the vertical pattern presents a sharp cutoff at ground-grazing angles and low sidelobes at negative elevation angles. Slotted waveguide radiators require involved design procedures but are relatively simple and neat to fabricate System Component P. Mahapatra, N. Balakrishnan - Microwave landing system - A favourite alternative to current ILS - IETE Technical Review, Vol. 2, No. 11, 1985

10. System Component https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

11. 2. Elevation Equipment: The elevation antenna is located above the runway The main features of the elevation antenna system ar e similar to those of the azimuth section except that beam is oscillatory in the vertical direction. T he fixed horizontal width of the beam is enough to cover the entire azimuth sector. The sector antenna transmits an out-of-coverage indication (OCI) signal to prevent erroneous indication due to antenna sidelobes. Even when an aircraft is outside the elevation coverage, at close ranges and/or with sensitive equipment, it may receive elevation signals from antenna sidelobes which also scan at the same rate as the main beam. This may produce misleading elevation information. To avoid such possibilities, an OCI signal is transmitted from the sector antenna which is part of the elevation antenna. Sidelobe identification is achieved through amplitude comparison. System Component P. Mahapatra, N. Balakrishnan - Microwave landing system - A favourite alternative to current ILS - IETE Technical Review, Vol. 2, No. 11, 1985

12. Other components of the system are: Flare. Although the standard has been developed to provide for flare elevation, this function is not intended for future implementation Back azimuth. Gives overshoot and departure guidance ± 20° of runway direction up to 15° in elevation. DME Range along the MLS course is provided not by markers but by a DME. For Cat II and III approaches a precision DME (DME/P) that is accurate to within 100 feet must be available. System Component https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

13. Features of Microwave Landing System There is no problem with back-course transmissions; a secondary system is provided to give overshoot and departure guidance ± 20° of runway direction up to 15° in elevation to a range of 10 nm and a height of 10,000 ft. 3 There are 200 channels available worldwide 1 The azimuth coverage is at least ± 40° of the runway on-course line (QDM) and glideslopes from .9° to 20° can be selected. The usable range is 20-30 nm from the MLS site; 20nm in the UK. 2 It operates in the SHF band, 5031 - 5090 MHZ. This enables it to be sited in hilly areas without having to level the site. Course deviation errors (bending) of the localiser and glidepath caused by aircraft, vehicles and buildings are no longer a problem because the MLS scanning beam can be interrupted and therefore avoids the reflections. 4 https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

14. Features of Microwave Landing System MLS gives positive automatic landing indications plus definite and continuous on/off flag indications for the localiser and glideslope needles. 7 Because of its increased azimuth and elevation coverage aircraft can choose their own approaches. This will increase runway utilisation and be beneficial to helicopters and STOL aircraft. 5 MLS is compatible with conventional localiser and glidepath instruments, EFIS, auto- pilot systems and area navigation equipment. 6 The aim is for all MLS equipped aircraft to operate to CAT III criteria. Figures 10.1, 10.2 and 10.3 below show some of these features. 8 https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

15. Features of Microwave Landing System MLS Coverage (The images used above are an example and not actual values) Approach Coverage Volume https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

16. Features of Microwave Landing System Typical MLS Flight Deck and Control Panel https://www.aircraftspruce.com/catalog/pdf/13-08721.pdf

17. Applications 1.Road and Rail navigation 2.Logistics and shipping services 3.Marine application 4.Military and commercial aviation 5.Precision agriculture 6.Autonomous driving (self driving cars) 7.Drone operation 8.Security and surveillance applications 9.Search and rescue operations 10.Medical application (tracking of patients requires special care) 11.Weather prediction and broadcast

18. Advantages & Limitations of Navigation Systems Easy to navigate and learn for all age groups It helps to improve vehicle traffic flow by guiding drivers about possible congested routes. There is no charge or fees to be paid by users to avail this service. The service is available anytime and anywhere. Moreover it is calibrated by its own and easy to be used by anyone. Inaccuracy Lack of Local Knowledge Driving Distraction Signal or Battery Failure Reliance on US Department of Defense Privacy Issues and Crime Commercial Exploitation

19. Advantages of MLS The Advantage of MLS is it can be used at any weather conditions. MLS provides higher range of altitude (20000 ft) and azimuth(60 degrees) comparing to ILS. IMLS can provide 200 channels while ILS provides only 20 channels, making conflicts between airports in the same area easily preventable. Furthermore, MLS can eliminate the service interruption caused by weather accumulation. This provides lower costs preparation, lower repair costs, lower costs for maintenance. Category III landings(blind landings)(as classified by FAA) can easily done. The frequency with the nearby airports will not be interfered. The antennas were much smaller, using a higher frequency signal. They also did not have to be placed at a specific location at the airport, and could "offset" their signals electronically. MLS signals covered a very wide fan-shaped area off the end of the runway, allowing controllers to direct aircraft approaching from a variety of directions or guide aircraft along a segmented approach. In comparison, ILS could only guide the aircraft down a single straight line, requiring controllers to distribute planes along that line. This provides lower costs preparation, lower repair costs, lower costs for maintenance.

20. MLS needs GPS,WAAS which cannot be done to every airports. Since now all the airport operates at ILS and equipped with ILS runways it is harder to change to MLS equipped runway. In ILS equipped runway MLS aircraft cannot be made to touchdown Costly to implement Its major competitor is the GBAS, that is being favoured more due to its cost effective nature over MLS. Along with the 32-element array ILS localiser antenna which is available, the MLS system though effective, must cut down on costs in order to stay relevant IFET-2014 Conference Proceedings Limitations of MLS

21. Conclusions We started our discussion with the various forms of electronic navigation present such as radio, radar and satellite navigation systems Furthermore, we discussed the need to develop an MLS system such as reduction in sensitive area, enhancement of the region of coverage, provision for receiver course selection MLS has the potential to provide significant fuel and time savings as well as flexibility in approach and take-off, compared to the current TLS. It has all the essential features to support the goals of safety, capacity, and economy in the approach and landing functions. Other examples of navigation systems that utilise GPS include: submarine navigation systems (which use inertial navigation and SONAR), Doppler MLS that we can look forward to in the future, along with the GNSS that is being widely used along with LPV approaches based on the EGNOS (WAAS-compatible) satellite system [India’s WAAS implementation: GAGAN]

22. THANK YOU MEMBERS : BOARDING PASS FLIGHT GATE SEAT B345 D8 29E Aditya Trivedi - 60002190010 Adrika Singh - 60002190011 Ajay Jain - 60002190012 Akshat Somani - 60002190013 Anushka Kanabar - 60002190014

23. References [1] IFET-2014 Conference Proceedings, International Journal Of Engineering Research and Technology (IJERT) [2] Poulose, M. & Mahapatra, Pravas & Balakrishnan, Narayanaswamy. (2015). Microwave Landing System—A Favoured Alternative to Current ILS. IETE Technical Review. 2. 375-382. 10.1080/02564602.1985.11437849. [3] Ding Wang, V V Davydov, & V Yu Rud (2021). Prospective directions for the development of microwave frequency standards for satellite navigation systems. Journal of Physics: Conference Series, 2086(1), 012073. 4] The book "Microwaves and Wireless Simplified" by Thomas S. Laverghetta by Artech House [5] https://www.duncanaviation.aero/intelligence/2 015/January/what-is-waas-lpv [6] https://en.wikipedia.org/wiki/Microwave_landing _system