I am not sure about ERDAS and ecognition, but sure you can import SAR data into ENVI easily 

Ya right. Using ENVI is the best option. Please find more details on the link below.

http://www.exelisvis.com/docs/synthesizingsir-cdata.html

I would like to draw your attention to the NEST DAT 5.0.16, it is free software so you can download from this website https://earth.esa.int/web/nest/home

You should save the SAR data in tiff format and then used it in eCognition software. You can use the ENVI for this format transformation.

@Mehdi Saberion, that's what i thought and did but the data didn't open.

@Mohsen Jafari, i did that but what happened is, after saving in that format the data loses its spatial information.

Thank You people, let me try your suggestions and will get back to you. 

try SARSCAPE software

I agree with Falah. Use NEST and export as TIFF.

Try PolSARPro! (http://earth.eo.esa.int/polsarpro/) It is free and allows you to explore the polarimetric characteristics of the datasets and exporting them to tiff as well. Recognizing that you are based in Joburg, are you interested in the Kruger Park supersite? I already processed this data for my master thesis and there are specific issues with the data format for this site. Contact me in private if this is the case. Cheers, Andreas

I wanted to ask if you managed to open the SIR-C data from EarthExplorer and how. I tried NEST, S1-Toolbox, SNAP, ERDAS, ENVI ect. but none of them worked. The format seems to be very specific and there isn't much information about it.

A- Use the CEOS Header Tool to Find Missing Information

1. From the Toolbox, select Radar > Open/Prepare Radar File > View Generic CEOS Header. The Enter Compressed Data Products Filename dialog appears.

2. Select the SAR leader file and click Open. The CEOS Header Report dialog appears.

3. Note the Processed Scene Range value. Enter this value in the Width (km) field of the SIR-C Header Parameters dialog when you later synthesize the data.

4. Note the Processed Scene Azimuth value. Enter this value in the Length (km) field of the SIR-C Header Parameters dialog when you later synthesize the data.

5. Note the Producttype value. Select the appropriate SAR Channel Type radio button in the SIR-C Header Parameters dialog when you later synthesize the data.

6. Close the CEOS Header Report dialog.

7. From the Toolbox, select Radar > Open/Prepare Radar File > View Generic CEOS Header again. The Enter Compressed Data Products Filename dialog appears.

8. Select the data file and click Open. The CEOS Header Report dialog appears.

9. Note the NumberofSamples and NumberofLines values. Enter these values in the Samples and Lines fields of the SIR-C Header Parameters dialog when you later synthesize the data.

10. Note the RecordInfo value. The last number in the array is the size of the image offset or embedded header. Enter this value in the Offset field of the SIR-C Header Parameters dialog when you later synthesize the data. If there are two fields labeled RecordInfo in the CEOS Header Report, then take the two large numbers at the end of these lines and add them to determine the image offset.

11. Now that you have the information you need, synthesize the SIR-C images. When you enter information in the SIR-C Header Parameters dialog, be sure to click the Yes radio button next to Strip Line Header?

B- Synthesize SIR-C Data

• From the Toolbox, select Radar > SIR-C > Synthesize SIR-C Data.

o The Input Data Products Files dialog appears. Use this dialog to read the SIR-C compressed scattering matrix files.

o Note: Do not open the Stokes matrix files using the File menu selection from the Toolbox.

• Click Open File. The Enter Filename dialog appears.
• Select a SIR-C scattering matrix (.cdp) filename. If the file is a valid ENVI compressed data file with all of the required parameters, ENVI adds it to one of the Selected Files fields in the Input Data Product Files dialog (depending on whether the file is P-, L-, or C-band data). If you followed the suggested file naming convention described previously, ENVI automatically adds the correct filenames for the other two files to the appropriate fields. Otherwise, repeat the file selection process for each of the bands.

o If the input file is not a valid ENVI compressed data file, the SIR-C Header Parameters dialog appears. Enter any missing parameters.

• Click OK. The Synthesize Parameters dialog appears.
• Set the synthesizing parameters.
• Select output to File or Memory.
• Click OK. All synthesized bands are placed in a single output file. ENVI adds the resulting output to the Layer Manager.