The software involves a GIS(Geographical Information System) with a database. The basic work had though started on Geomedia, but one is free to choose any open GIS software or design his/her own. The database engine also may be any, as per the programmers choice. But the source code is required to be shared.
The software should enable a user to import a map with height information as well, choose a customised "radio frequency transmitter" and place it anywhere on the GIS map. The attributes that may be added to the transmitter are
-Trans and receive frequencies,
-minimum frequency separation required (and the software should check if this separation is maintained while the user enters the trans and receive frequencies or else it throws an error),
-minimum threshold receive power level (if the received power is > minimum threshold power, the receiver will receive/ interfered or else not)
-harmonic suppression level(the multiple harmonics of the transmission frequency are suppressed by this amount from the transmitter power output set by the user)
-any other attributes that may be added at a later stage.
Accordingly, the user has set say 4 transmitters. Lets call them A1, A2 pertaining to link [url removed, login to view] B1, B2 pertaining to link B.
A1 has trans freq as 410 Mhz and receive freq as 450Mhz with 35 Mhz min separation between them. A2 has the freq just the opposite, i.e. Trans freq as 450 and receive freq as 410 Mhz so that A1 can communicate with A2 only and vice versa. So it is a one-to-one radio link, plotted on a GIS platform with the specific location seen.
Now A1 will actually be able to talk to A2 if the following are true
- if the power that is transmitted by the transmitter at a user-set power output is received at the receiver A2(after suffering losses due to travel of the radio waves due to free space travel (this factor is dependant on aerial distance between A1 and A2), or vegetation loss or weather loss etc.) and the received power is more than the threshold power of the receiver A2.
-same calculations from A2 to A1.
The A1- A2 radio link is considered feasible only if A1 to A2 as well as A2 to A1 is feasible. So there has to be a button called "Link feasibility" which when clicked will be able to tell us that which all links are feasible and which all are non feasible, with a color indication (say green for feasible and red for non feasible) marked on the map. So the output will indicate that link A is feasible but link B is, say, not feasible due with receive power at B1 as *** and receive power at B2 as ***. This is requirement one.
There may be a case that there is a mountain or hill feature between A1 and A2 and so the the calculation is not so simple and depends on factors other than distance as in previous case. So the "knife edge refraction losses" (that depends upon the transmission frequency, heights of the transmitter and receiver, height of interfering object and distance from transmitter) adds up to the "total losses" and further reduces the power received at the receiver. If the power received is less than the threshold, then link is not feasible.
The height information and the information of the interfering feature can be automatically obtained from the GIS platform (say by drawing a line between the transmitter and receiver and if any of the contours get cut, then there is an interfering feature. If the slope of the line joining the transmitter and the contour-line intersection point is less than that of the subsequent intersection point and is positive, then there IS an interfering feature). If all these factors are considered then only the link feasibility study is realistic and the requirement one is treatable as complete.
So now that the links are established, it is required to see whether the links interfere with each other or not. So firstly, the trans frequency of A1 in link A has to be the receive frequency of A2 in the same link A, and the same frequency cannot be allotted to another set of transmitters.
Also, the harmonics (double and triple of the freq trans frequency ) also gets radiated from the transmitter station which is infact a spurious transmission. But the power level is suppressed from the user-allotted power output by a factor which is the harmonic suppression level. So if this spurious power radiated by the transmitter is effecting any other receiver in another link, then it is interfering. Hence there has to be a button called "interference study" which when clicked will give the list and pictorial depiction of all those transmitters that are causing interference so that user can change their trans frequency. Whether the transmitter is transmitting of not, can be found out by similar method used in requirement one above but now the transmit frequency is actually the harmonic spurious frequency and the output power in the calculation is the actual transmit power minus the harmonic suppression in decibels. So this runs the same check (including the knife edge refraction) in a loop with each transmitter other than that which has the same link id. This is requirement two.
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We are working in GIS for the past 5 years. we will develope it using arcObjects (preferably) and geodatabase will be used to fullfil the need of database functionality.